1 // SPDX-License-Identifier: GPL-2.0-or-later
2 // SPI init/core code
3 //
4 // Copyright (C) 2005 David Brownell
5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
6
7 #include <linux/acpi.h>
8 #include <linux/cache.h>
9 #include <linux/clk/clk-conf.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/dmaengine.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/export.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/highmem.h>
17 #include <linux/idr.h>
18 #include <linux/init.h>
19 #include <linux/ioport.h>
20 #include <linux/kernel.h>
21 #include <linux/kthread.h>
22 #include <linux/mod_devicetable.h>
23 #include <linux/mutex.h>
24 #include <linux/of_device.h>
25 #include <linux/of_irq.h>
26 #include <linux/percpu.h>
27 #include <linux/platform_data/x86/apple.h>
28 #include <linux/pm_domain.h>
29 #include <linux/pm_runtime.h>
30 #include <linux/property.h>
31 #include <linux/ptp_clock_kernel.h>
32 #include <linux/sched/rt.h>
33 #include <linux/slab.h>
34 #include <linux/spi/spi.h>
35 #include <linux/spi/spi-mem.h>
36 #include <uapi/linux/sched/types.h>
37
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/spi.h>
40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
42
43 #include "internals.h"
44
45 static DEFINE_IDR(spi_master_idr);
46
spidev_release(struct device * dev)47 static void spidev_release(struct device *dev)
48 {
49 struct spi_device *spi = to_spi_device(dev);
50
51 spi_controller_put(spi->controller);
52 kfree(spi->driver_override);
53 free_percpu(spi->pcpu_statistics);
54 kfree(spi);
55 }
56
57 static ssize_t
modalias_show(struct device * dev,struct device_attribute * a,char * buf)58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 {
60 const struct spi_device *spi = to_spi_device(dev);
61 int len;
62
63 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
64 if (len != -ENODEV)
65 return len;
66
67 return sysfs_emit(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 }
69 static DEVICE_ATTR_RO(modalias);
70
driver_override_store(struct device * dev,struct device_attribute * a,const char * buf,size_t count)71 static ssize_t driver_override_store(struct device *dev,
72 struct device_attribute *a,
73 const char *buf, size_t count)
74 {
75 struct spi_device *spi = to_spi_device(dev);
76 int ret;
77
78 ret = driver_set_override(dev, &spi->driver_override, buf, count);
79 if (ret)
80 return ret;
81
82 return count;
83 }
84
driver_override_show(struct device * dev,struct device_attribute * a,char * buf)85 static ssize_t driver_override_show(struct device *dev,
86 struct device_attribute *a, char *buf)
87 {
88 const struct spi_device *spi = to_spi_device(dev);
89 ssize_t len;
90
91 device_lock(dev);
92 len = sysfs_emit(buf, "%s\n", spi->driver_override ? : "");
93 device_unlock(dev);
94 return len;
95 }
96 static DEVICE_ATTR_RW(driver_override);
97
spi_alloc_pcpu_stats(struct device * dev)98 static struct spi_statistics __percpu *spi_alloc_pcpu_stats(struct device *dev)
99 {
100 struct spi_statistics __percpu *pcpu_stats;
101
102 if (dev)
103 pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
104 else
105 pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
106
107 if (pcpu_stats) {
108 int cpu;
109
110 for_each_possible_cpu(cpu) {
111 struct spi_statistics *stat;
112
113 stat = per_cpu_ptr(pcpu_stats, cpu);
114 u64_stats_init(&stat->syncp);
115 }
116 }
117 return pcpu_stats;
118 }
119
spi_emit_pcpu_stats(struct spi_statistics __percpu * stat,char * buf,size_t offset)120 static ssize_t spi_emit_pcpu_stats(struct spi_statistics __percpu *stat,
121 char *buf, size_t offset)
122 {
123 u64 val = 0;
124 int i;
125
126 for_each_possible_cpu(i) {
127 const struct spi_statistics *pcpu_stats;
128 u64_stats_t *field;
129 unsigned int start;
130 u64 inc;
131
132 pcpu_stats = per_cpu_ptr(stat, i);
133 field = (void *)pcpu_stats + offset;
134 do {
135 start = u64_stats_fetch_begin(&pcpu_stats->syncp);
136 inc = u64_stats_read(field);
137 } while (u64_stats_fetch_retry(&pcpu_stats->syncp, start));
138 val += inc;
139 }
140 return sysfs_emit(buf, "%llu\n", val);
141 }
142
143 #define SPI_STATISTICS_ATTRS(field, file) \
144 static ssize_t spi_controller_##field##_show(struct device *dev, \
145 struct device_attribute *attr, \
146 char *buf) \
147 { \
148 struct spi_controller *ctlr = container_of(dev, \
149 struct spi_controller, dev); \
150 return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
151 } \
152 static struct device_attribute dev_attr_spi_controller_##field = { \
153 .attr = { .name = file, .mode = 0444 }, \
154 .show = spi_controller_##field##_show, \
155 }; \
156 static ssize_t spi_device_##field##_show(struct device *dev, \
157 struct device_attribute *attr, \
158 char *buf) \
159 { \
160 struct spi_device *spi = to_spi_device(dev); \
161 return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
162 } \
163 static struct device_attribute dev_attr_spi_device_##field = { \
164 .attr = { .name = file, .mode = 0444 }, \
165 .show = spi_device_##field##_show, \
166 }
167
168 #define SPI_STATISTICS_SHOW_NAME(name, file, field) \
169 static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
170 char *buf) \
171 { \
172 return spi_emit_pcpu_stats(stat, buf, \
173 offsetof(struct spi_statistics, field)); \
174 } \
175 SPI_STATISTICS_ATTRS(name, file)
176
177 #define SPI_STATISTICS_SHOW(field) \
178 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
179 field)
180
181 SPI_STATISTICS_SHOW(messages);
182 SPI_STATISTICS_SHOW(transfers);
183 SPI_STATISTICS_SHOW(errors);
184 SPI_STATISTICS_SHOW(timedout);
185
186 SPI_STATISTICS_SHOW(spi_sync);
187 SPI_STATISTICS_SHOW(spi_sync_immediate);
188 SPI_STATISTICS_SHOW(spi_async);
189
190 SPI_STATISTICS_SHOW(bytes);
191 SPI_STATISTICS_SHOW(bytes_rx);
192 SPI_STATISTICS_SHOW(bytes_tx);
193
194 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
195 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
196 "transfer_bytes_histo_" number, \
197 transfer_bytes_histo[index])
198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
214 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
215
216 SPI_STATISTICS_SHOW(transfers_split_maxsize);
217
218 static struct attribute *spi_dev_attrs[] = {
219 &dev_attr_modalias.attr,
220 &dev_attr_driver_override.attr,
221 NULL,
222 };
223
224 static const struct attribute_group spi_dev_group = {
225 .attrs = spi_dev_attrs,
226 };
227
228 static struct attribute *spi_device_statistics_attrs[] = {
229 &dev_attr_spi_device_messages.attr,
230 &dev_attr_spi_device_transfers.attr,
231 &dev_attr_spi_device_errors.attr,
232 &dev_attr_spi_device_timedout.attr,
233 &dev_attr_spi_device_spi_sync.attr,
234 &dev_attr_spi_device_spi_sync_immediate.attr,
235 &dev_attr_spi_device_spi_async.attr,
236 &dev_attr_spi_device_bytes.attr,
237 &dev_attr_spi_device_bytes_rx.attr,
238 &dev_attr_spi_device_bytes_tx.attr,
239 &dev_attr_spi_device_transfer_bytes_histo0.attr,
240 &dev_attr_spi_device_transfer_bytes_histo1.attr,
241 &dev_attr_spi_device_transfer_bytes_histo2.attr,
242 &dev_attr_spi_device_transfer_bytes_histo3.attr,
243 &dev_attr_spi_device_transfer_bytes_histo4.attr,
244 &dev_attr_spi_device_transfer_bytes_histo5.attr,
245 &dev_attr_spi_device_transfer_bytes_histo6.attr,
246 &dev_attr_spi_device_transfer_bytes_histo7.attr,
247 &dev_attr_spi_device_transfer_bytes_histo8.attr,
248 &dev_attr_spi_device_transfer_bytes_histo9.attr,
249 &dev_attr_spi_device_transfer_bytes_histo10.attr,
250 &dev_attr_spi_device_transfer_bytes_histo11.attr,
251 &dev_attr_spi_device_transfer_bytes_histo12.attr,
252 &dev_attr_spi_device_transfer_bytes_histo13.attr,
253 &dev_attr_spi_device_transfer_bytes_histo14.attr,
254 &dev_attr_spi_device_transfer_bytes_histo15.attr,
255 &dev_attr_spi_device_transfer_bytes_histo16.attr,
256 &dev_attr_spi_device_transfers_split_maxsize.attr,
257 NULL,
258 };
259
260 static const struct attribute_group spi_device_statistics_group = {
261 .name = "statistics",
262 .attrs = spi_device_statistics_attrs,
263 };
264
265 static const struct attribute_group *spi_dev_groups[] = {
266 &spi_dev_group,
267 &spi_device_statistics_group,
268 NULL,
269 };
270
271 static struct attribute *spi_controller_statistics_attrs[] = {
272 &dev_attr_spi_controller_messages.attr,
273 &dev_attr_spi_controller_transfers.attr,
274 &dev_attr_spi_controller_errors.attr,
275 &dev_attr_spi_controller_timedout.attr,
276 &dev_attr_spi_controller_spi_sync.attr,
277 &dev_attr_spi_controller_spi_sync_immediate.attr,
278 &dev_attr_spi_controller_spi_async.attr,
279 &dev_attr_spi_controller_bytes.attr,
280 &dev_attr_spi_controller_bytes_rx.attr,
281 &dev_attr_spi_controller_bytes_tx.attr,
282 &dev_attr_spi_controller_transfer_bytes_histo0.attr,
283 &dev_attr_spi_controller_transfer_bytes_histo1.attr,
284 &dev_attr_spi_controller_transfer_bytes_histo2.attr,
285 &dev_attr_spi_controller_transfer_bytes_histo3.attr,
286 &dev_attr_spi_controller_transfer_bytes_histo4.attr,
287 &dev_attr_spi_controller_transfer_bytes_histo5.attr,
288 &dev_attr_spi_controller_transfer_bytes_histo6.attr,
289 &dev_attr_spi_controller_transfer_bytes_histo7.attr,
290 &dev_attr_spi_controller_transfer_bytes_histo8.attr,
291 &dev_attr_spi_controller_transfer_bytes_histo9.attr,
292 &dev_attr_spi_controller_transfer_bytes_histo10.attr,
293 &dev_attr_spi_controller_transfer_bytes_histo11.attr,
294 &dev_attr_spi_controller_transfer_bytes_histo12.attr,
295 &dev_attr_spi_controller_transfer_bytes_histo13.attr,
296 &dev_attr_spi_controller_transfer_bytes_histo14.attr,
297 &dev_attr_spi_controller_transfer_bytes_histo15.attr,
298 &dev_attr_spi_controller_transfer_bytes_histo16.attr,
299 &dev_attr_spi_controller_transfers_split_maxsize.attr,
300 NULL,
301 };
302
303 static const struct attribute_group spi_controller_statistics_group = {
304 .name = "statistics",
305 .attrs = spi_controller_statistics_attrs,
306 };
307
308 static const struct attribute_group *spi_master_groups[] = {
309 &spi_controller_statistics_group,
310 NULL,
311 };
312
spi_statistics_add_transfer_stats(struct spi_statistics __percpu * pcpu_stats,struct spi_transfer * xfer,struct spi_message * msg)313 static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
314 struct spi_transfer *xfer,
315 struct spi_message *msg)
316 {
317 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
318 struct spi_statistics *stats;
319
320 if (l2len < 0)
321 l2len = 0;
322
323 get_cpu();
324 stats = this_cpu_ptr(pcpu_stats);
325 u64_stats_update_begin(&stats->syncp);
326
327 u64_stats_inc(&stats->transfers);
328 u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
329
330 u64_stats_add(&stats->bytes, xfer->len);
331 if (spi_valid_txbuf(msg, xfer))
332 u64_stats_add(&stats->bytes_tx, xfer->len);
333 if (spi_valid_rxbuf(msg, xfer))
334 u64_stats_add(&stats->bytes_rx, xfer->len);
335
336 u64_stats_update_end(&stats->syncp);
337 put_cpu();
338 }
339
340 /*
341 * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
342 * and the sysfs version makes coldplug work too.
343 */
spi_match_id(const struct spi_device_id * id,const char * name)344 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
345 {
346 while (id->name[0]) {
347 if (!strcmp(name, id->name))
348 return id;
349 id++;
350 }
351 return NULL;
352 }
353
spi_get_device_id(const struct spi_device * sdev)354 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
355 {
356 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
357
358 return spi_match_id(sdrv->id_table, sdev->modalias);
359 }
360 EXPORT_SYMBOL_GPL(spi_get_device_id);
361
spi_get_device_match_data(const struct spi_device * sdev)362 const void *spi_get_device_match_data(const struct spi_device *sdev)
363 {
364 const void *match;
365
366 match = device_get_match_data(&sdev->dev);
367 if (match)
368 return match;
369
370 return (const void *)spi_get_device_id(sdev)->driver_data;
371 }
372 EXPORT_SYMBOL_GPL(spi_get_device_match_data);
373
spi_match_device(struct device * dev,const struct device_driver * drv)374 static int spi_match_device(struct device *dev, const struct device_driver *drv)
375 {
376 const struct spi_device *spi = to_spi_device(dev);
377 const struct spi_driver *sdrv = to_spi_driver(drv);
378
379 /* Check override first, and if set, only use the named driver */
380 if (spi->driver_override)
381 return strcmp(spi->driver_override, drv->name) == 0;
382
383 /* Attempt an OF style match */
384 if (of_driver_match_device(dev, drv))
385 return 1;
386
387 /* Then try ACPI */
388 if (acpi_driver_match_device(dev, drv))
389 return 1;
390
391 if (sdrv->id_table)
392 return !!spi_match_id(sdrv->id_table, spi->modalias);
393
394 return strcmp(spi->modalias, drv->name) == 0;
395 }
396
spi_uevent(const struct device * dev,struct kobj_uevent_env * env)397 static int spi_uevent(const struct device *dev, struct kobj_uevent_env *env)
398 {
399 const struct spi_device *spi = to_spi_device(dev);
400 int rc;
401
402 rc = acpi_device_uevent_modalias(dev, env);
403 if (rc != -ENODEV)
404 return rc;
405
406 return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
407 }
408
spi_probe(struct device * dev)409 static int spi_probe(struct device *dev)
410 {
411 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
412 struct spi_device *spi = to_spi_device(dev);
413 struct fwnode_handle *fwnode = dev_fwnode(dev);
414 int ret;
415
416 ret = of_clk_set_defaults(dev->of_node, false);
417 if (ret)
418 return ret;
419
420 if (is_of_node(fwnode))
421 spi->irq = of_irq_get(dev->of_node, 0);
422 else if (is_acpi_device_node(fwnode) && spi->irq < 0)
423 spi->irq = acpi_dev_gpio_irq_get(to_acpi_device_node(fwnode), 0);
424 if (spi->irq == -EPROBE_DEFER)
425 return dev_err_probe(dev, spi->irq, "Failed to get irq\n");
426 if (spi->irq < 0)
427 spi->irq = 0;
428
429 ret = dev_pm_domain_attach(dev, true);
430 if (ret)
431 return ret;
432
433 if (sdrv->probe) {
434 ret = sdrv->probe(spi);
435 if (ret)
436 dev_pm_domain_detach(dev, true);
437 }
438
439 return ret;
440 }
441
spi_remove(struct device * dev)442 static void spi_remove(struct device *dev)
443 {
444 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
445
446 if (sdrv->remove)
447 sdrv->remove(to_spi_device(dev));
448
449 dev_pm_domain_detach(dev, true);
450 }
451
spi_shutdown(struct device * dev)452 static void spi_shutdown(struct device *dev)
453 {
454 if (dev->driver) {
455 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
456
457 if (sdrv->shutdown)
458 sdrv->shutdown(to_spi_device(dev));
459 }
460 }
461
462 const struct bus_type spi_bus_type = {
463 .name = "spi",
464 .dev_groups = spi_dev_groups,
465 .match = spi_match_device,
466 .uevent = spi_uevent,
467 .probe = spi_probe,
468 .remove = spi_remove,
469 .shutdown = spi_shutdown,
470 };
471 EXPORT_SYMBOL_GPL(spi_bus_type);
472
473 /**
474 * __spi_register_driver - register a SPI driver
475 * @owner: owner module of the driver to register
476 * @sdrv: the driver to register
477 * Context: can sleep
478 *
479 * Return: zero on success, else a negative error code.
480 */
__spi_register_driver(struct module * owner,struct spi_driver * sdrv)481 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
482 {
483 sdrv->driver.owner = owner;
484 sdrv->driver.bus = &spi_bus_type;
485
486 /*
487 * For Really Good Reasons we use spi: modaliases not of:
488 * modaliases for DT so module autoloading won't work if we
489 * don't have a spi_device_id as well as a compatible string.
490 */
491 if (sdrv->driver.of_match_table) {
492 const struct of_device_id *of_id;
493
494 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
495 of_id++) {
496 const char *of_name;
497
498 /* Strip off any vendor prefix */
499 of_name = strnchr(of_id->compatible,
500 sizeof(of_id->compatible), ',');
501 if (of_name)
502 of_name++;
503 else
504 of_name = of_id->compatible;
505
506 if (sdrv->id_table) {
507 const struct spi_device_id *spi_id;
508
509 spi_id = spi_match_id(sdrv->id_table, of_name);
510 if (spi_id)
511 continue;
512 } else {
513 if (strcmp(sdrv->driver.name, of_name) == 0)
514 continue;
515 }
516
517 pr_warn("SPI driver %s has no spi_device_id for %s\n",
518 sdrv->driver.name, of_id->compatible);
519 }
520 }
521
522 return driver_register(&sdrv->driver);
523 }
524 EXPORT_SYMBOL_GPL(__spi_register_driver);
525
526 /*-------------------------------------------------------------------------*/
527
528 /*
529 * SPI devices should normally not be created by SPI device drivers; that
530 * would make them board-specific. Similarly with SPI controller drivers.
531 * Device registration normally goes into like arch/.../mach.../board-YYY.c
532 * with other readonly (flashable) information about mainboard devices.
533 */
534
535 struct boardinfo {
536 struct list_head list;
537 struct spi_board_info board_info;
538 };
539
540 static LIST_HEAD(board_list);
541 static LIST_HEAD(spi_controller_list);
542
543 /*
544 * Used to protect add/del operation for board_info list and
545 * spi_controller list, and their matching process also used
546 * to protect object of type struct idr.
547 */
548 static DEFINE_MUTEX(board_lock);
549
550 /**
551 * spi_alloc_device - Allocate a new SPI device
552 * @ctlr: Controller to which device is connected
553 * Context: can sleep
554 *
555 * Allows a driver to allocate and initialize a spi_device without
556 * registering it immediately. This allows a driver to directly
557 * fill the spi_device with device parameters before calling
558 * spi_add_device() on it.
559 *
560 * Caller is responsible to call spi_add_device() on the returned
561 * spi_device structure to add it to the SPI controller. If the caller
562 * needs to discard the spi_device without adding it, then it should
563 * call spi_dev_put() on it.
564 *
565 * Return: a pointer to the new device, or NULL.
566 */
spi_alloc_device(struct spi_controller * ctlr)567 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
568 {
569 struct spi_device *spi;
570
571 if (!spi_controller_get(ctlr))
572 return NULL;
573
574 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
575 if (!spi) {
576 spi_controller_put(ctlr);
577 return NULL;
578 }
579
580 spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
581 if (!spi->pcpu_statistics) {
582 kfree(spi);
583 spi_controller_put(ctlr);
584 return NULL;
585 }
586
587 spi->controller = ctlr;
588 spi->dev.parent = &ctlr->dev;
589 spi->dev.bus = &spi_bus_type;
590 spi->dev.release = spidev_release;
591 spi->mode = ctlr->buswidth_override_bits;
592
593 device_initialize(&spi->dev);
594 return spi;
595 }
596 EXPORT_SYMBOL_GPL(spi_alloc_device);
597
spi_dev_set_name(struct spi_device * spi)598 static void spi_dev_set_name(struct spi_device *spi)
599 {
600 struct device *dev = &spi->dev;
601 struct fwnode_handle *fwnode = dev_fwnode(dev);
602
603 if (is_acpi_device_node(fwnode)) {
604 dev_set_name(dev, "spi-%s", acpi_dev_name(to_acpi_device_node(fwnode)));
605 return;
606 }
607
608 if (is_software_node(fwnode)) {
609 dev_set_name(dev, "spi-%pfwP", fwnode);
610 return;
611 }
612
613 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
614 spi_get_chipselect(spi, 0));
615 }
616
617 /*
618 * Zero(0) is a valid physical CS value and can be located at any
619 * logical CS in the spi->chip_select[]. If all the physical CS
620 * are initialized to 0 then It would be difficult to differentiate
621 * between a valid physical CS 0 & an unused logical CS whose physical
622 * CS can be 0. As a solution to this issue initialize all the CS to -1.
623 * Now all the unused logical CS will have -1 physical CS value & can be
624 * ignored while performing physical CS validity checks.
625 */
626 #define SPI_INVALID_CS ((s8)-1)
627
is_valid_cs(s8 chip_select)628 static inline bool is_valid_cs(s8 chip_select)
629 {
630 return chip_select != SPI_INVALID_CS;
631 }
632
spi_dev_check_cs(struct device * dev,struct spi_device * spi,u8 idx,struct spi_device * new_spi,u8 new_idx)633 static inline int spi_dev_check_cs(struct device *dev,
634 struct spi_device *spi, u8 idx,
635 struct spi_device *new_spi, u8 new_idx)
636 {
637 u8 cs, cs_new;
638 u8 idx_new;
639
640 cs = spi_get_chipselect(spi, idx);
641 for (idx_new = new_idx; idx_new < SPI_CS_CNT_MAX; idx_new++) {
642 cs_new = spi_get_chipselect(new_spi, idx_new);
643 if (is_valid_cs(cs) && is_valid_cs(cs_new) && cs == cs_new) {
644 dev_err(dev, "chipselect %u already in use\n", cs_new);
645 return -EBUSY;
646 }
647 }
648 return 0;
649 }
650
spi_dev_check(struct device * dev,void * data)651 static int spi_dev_check(struct device *dev, void *data)
652 {
653 struct spi_device *spi = to_spi_device(dev);
654 struct spi_device *new_spi = data;
655 int status, idx;
656
657 if (spi->controller == new_spi->controller) {
658 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
659 status = spi_dev_check_cs(dev, spi, idx, new_spi, 0);
660 if (status)
661 return status;
662 }
663 }
664 return 0;
665 }
666
spi_cleanup(struct spi_device * spi)667 static void spi_cleanup(struct spi_device *spi)
668 {
669 if (spi->controller->cleanup)
670 spi->controller->cleanup(spi);
671 }
672
__spi_add_device(struct spi_device * spi)673 static int __spi_add_device(struct spi_device *spi)
674 {
675 struct spi_controller *ctlr = spi->controller;
676 struct device *dev = ctlr->dev.parent;
677 int status, idx;
678 u8 cs;
679
680 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
681 /* Chipselects are numbered 0..max; validate. */
682 cs = spi_get_chipselect(spi, idx);
683 if (is_valid_cs(cs) && cs >= ctlr->num_chipselect) {
684 dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
685 ctlr->num_chipselect);
686 return -EINVAL;
687 }
688 }
689
690 /*
691 * Make sure that multiple logical CS doesn't map to the same physical CS.
692 * For example, spi->chip_select[0] != spi->chip_select[1] and so on.
693 */
694 if (!spi_controller_is_target(ctlr)) {
695 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
696 status = spi_dev_check_cs(dev, spi, idx, spi, idx + 1);
697 if (status)
698 return status;
699 }
700 }
701
702 /* Set the bus ID string */
703 spi_dev_set_name(spi);
704
705 /*
706 * We need to make sure there's no other device with this
707 * chipselect **BEFORE** we call setup(), else we'll trash
708 * its configuration.
709 */
710 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
711 if (status)
712 return status;
713
714 /* Controller may unregister concurrently */
715 if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
716 !device_is_registered(&ctlr->dev)) {
717 return -ENODEV;
718 }
719
720 if (ctlr->cs_gpiods) {
721 u8 cs;
722
723 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
724 cs = spi_get_chipselect(spi, idx);
725 if (is_valid_cs(cs))
726 spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]);
727 }
728 }
729
730 /*
731 * Drivers may modify this initial i/o setup, but will
732 * normally rely on the device being setup. Devices
733 * using SPI_CS_HIGH can't coexist well otherwise...
734 */
735 status = spi_setup(spi);
736 if (status < 0) {
737 dev_err(dev, "can't setup %s, status %d\n",
738 dev_name(&spi->dev), status);
739 return status;
740 }
741
742 /* Device may be bound to an active driver when this returns */
743 status = device_add(&spi->dev);
744 if (status < 0) {
745 dev_err(dev, "can't add %s, status %d\n",
746 dev_name(&spi->dev), status);
747 spi_cleanup(spi);
748 } else {
749 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
750 }
751
752 return status;
753 }
754
755 /**
756 * spi_add_device - Add spi_device allocated with spi_alloc_device
757 * @spi: spi_device to register
758 *
759 * Companion function to spi_alloc_device. Devices allocated with
760 * spi_alloc_device can be added onto the SPI bus with this function.
761 *
762 * Return: 0 on success; negative errno on failure
763 */
spi_add_device(struct spi_device * spi)764 int spi_add_device(struct spi_device *spi)
765 {
766 struct spi_controller *ctlr = spi->controller;
767 int status;
768
769 /* Set the bus ID string */
770 spi_dev_set_name(spi);
771
772 mutex_lock(&ctlr->add_lock);
773 status = __spi_add_device(spi);
774 mutex_unlock(&ctlr->add_lock);
775 return status;
776 }
777 EXPORT_SYMBOL_GPL(spi_add_device);
778
spi_set_all_cs_unused(struct spi_device * spi)779 static void spi_set_all_cs_unused(struct spi_device *spi)
780 {
781 u8 idx;
782
783 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
784 spi_set_chipselect(spi, idx, SPI_INVALID_CS);
785 }
786
787 /**
788 * spi_new_device - instantiate one new SPI device
789 * @ctlr: Controller to which device is connected
790 * @chip: Describes the SPI device
791 * Context: can sleep
792 *
793 * On typical mainboards, this is purely internal; and it's not needed
794 * after board init creates the hard-wired devices. Some development
795 * platforms may not be able to use spi_register_board_info though, and
796 * this is exported so that for example a USB or parport based adapter
797 * driver could add devices (which it would learn about out-of-band).
798 *
799 * Return: the new device, or NULL.
800 */
spi_new_device(struct spi_controller * ctlr,struct spi_board_info * chip)801 struct spi_device *spi_new_device(struct spi_controller *ctlr,
802 struct spi_board_info *chip)
803 {
804 struct spi_device *proxy;
805 int status;
806
807 /*
808 * NOTE: caller did any chip->bus_num checks necessary.
809 *
810 * Also, unless we change the return value convention to use
811 * error-or-pointer (not NULL-or-pointer), troubleshootability
812 * suggests syslogged diagnostics are best here (ugh).
813 */
814
815 proxy = spi_alloc_device(ctlr);
816 if (!proxy)
817 return NULL;
818
819 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
820
821 /* Use provided chip-select for proxy device */
822 spi_set_all_cs_unused(proxy);
823 spi_set_chipselect(proxy, 0, chip->chip_select);
824
825 proxy->max_speed_hz = chip->max_speed_hz;
826 proxy->mode = chip->mode;
827 proxy->irq = chip->irq;
828 strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
829 proxy->dev.platform_data = (void *) chip->platform_data;
830 proxy->controller_data = chip->controller_data;
831 proxy->controller_state = NULL;
832 /*
833 * By default spi->chip_select[0] will hold the physical CS number,
834 * so set bit 0 in spi->cs_index_mask.
835 */
836 proxy->cs_index_mask = BIT(0);
837
838 if (chip->swnode) {
839 status = device_add_software_node(&proxy->dev, chip->swnode);
840 if (status) {
841 dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
842 chip->modalias, status);
843 goto err_dev_put;
844 }
845 }
846
847 status = spi_add_device(proxy);
848 if (status < 0)
849 goto err_dev_put;
850
851 return proxy;
852
853 err_dev_put:
854 device_remove_software_node(&proxy->dev);
855 spi_dev_put(proxy);
856 return NULL;
857 }
858 EXPORT_SYMBOL_GPL(spi_new_device);
859
860 /**
861 * spi_unregister_device - unregister a single SPI device
862 * @spi: spi_device to unregister
863 *
864 * Start making the passed SPI device vanish. Normally this would be handled
865 * by spi_unregister_controller().
866 */
spi_unregister_device(struct spi_device * spi)867 void spi_unregister_device(struct spi_device *spi)
868 {
869 struct fwnode_handle *fwnode;
870
871 if (!spi)
872 return;
873
874 fwnode = dev_fwnode(&spi->dev);
875 if (is_of_node(fwnode)) {
876 of_node_clear_flag(to_of_node(fwnode), OF_POPULATED);
877 of_node_put(to_of_node(fwnode));
878 } else if (is_acpi_device_node(fwnode)) {
879 acpi_device_clear_enumerated(to_acpi_device_node(fwnode));
880 }
881 device_remove_software_node(&spi->dev);
882 device_del(&spi->dev);
883 spi_cleanup(spi);
884 put_device(&spi->dev);
885 }
886 EXPORT_SYMBOL_GPL(spi_unregister_device);
887
spi_match_controller_to_boardinfo(struct spi_controller * ctlr,struct spi_board_info * bi)888 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
889 struct spi_board_info *bi)
890 {
891 struct spi_device *dev;
892
893 if (ctlr->bus_num != bi->bus_num)
894 return;
895
896 dev = spi_new_device(ctlr, bi);
897 if (!dev)
898 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
899 bi->modalias);
900 }
901
902 /**
903 * spi_register_board_info - register SPI devices for a given board
904 * @info: array of chip descriptors
905 * @n: how many descriptors are provided
906 * Context: can sleep
907 *
908 * Board-specific early init code calls this (probably during arch_initcall)
909 * with segments of the SPI device table. Any device nodes are created later,
910 * after the relevant parent SPI controller (bus_num) is defined. We keep
911 * this table of devices forever, so that reloading a controller driver will
912 * not make Linux forget about these hard-wired devices.
913 *
914 * Other code can also call this, e.g. a particular add-on board might provide
915 * SPI devices through its expansion connector, so code initializing that board
916 * would naturally declare its SPI devices.
917 *
918 * The board info passed can safely be __initdata ... but be careful of
919 * any embedded pointers (platform_data, etc), they're copied as-is.
920 *
921 * Return: zero on success, else a negative error code.
922 */
spi_register_board_info(struct spi_board_info const * info,unsigned n)923 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
924 {
925 struct boardinfo *bi;
926 int i;
927
928 if (!n)
929 return 0;
930
931 bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
932 if (!bi)
933 return -ENOMEM;
934
935 for (i = 0; i < n; i++, bi++, info++) {
936 struct spi_controller *ctlr;
937
938 memcpy(&bi->board_info, info, sizeof(*info));
939
940 mutex_lock(&board_lock);
941 list_add_tail(&bi->list, &board_list);
942 list_for_each_entry(ctlr, &spi_controller_list, list)
943 spi_match_controller_to_boardinfo(ctlr,
944 &bi->board_info);
945 mutex_unlock(&board_lock);
946 }
947
948 return 0;
949 }
950
951 /*-------------------------------------------------------------------------*/
952
953 /* Core methods for SPI resource management */
954
955 /**
956 * spi_res_alloc - allocate a spi resource that is life-cycle managed
957 * during the processing of a spi_message while using
958 * spi_transfer_one
959 * @spi: the SPI device for which we allocate memory
960 * @release: the release code to execute for this resource
961 * @size: size to alloc and return
962 * @gfp: GFP allocation flags
963 *
964 * Return: the pointer to the allocated data
965 *
966 * This may get enhanced in the future to allocate from a memory pool
967 * of the @spi_device or @spi_controller to avoid repeated allocations.
968 */
spi_res_alloc(struct spi_device * spi,spi_res_release_t release,size_t size,gfp_t gfp)969 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
970 size_t size, gfp_t gfp)
971 {
972 struct spi_res *sres;
973
974 sres = kzalloc(sizeof(*sres) + size, gfp);
975 if (!sres)
976 return NULL;
977
978 INIT_LIST_HEAD(&sres->entry);
979 sres->release = release;
980
981 return sres->data;
982 }
983
984 /**
985 * spi_res_free - free an SPI resource
986 * @res: pointer to the custom data of a resource
987 */
spi_res_free(void * res)988 static void spi_res_free(void *res)
989 {
990 struct spi_res *sres = container_of(res, struct spi_res, data);
991
992 WARN_ON(!list_empty(&sres->entry));
993 kfree(sres);
994 }
995
996 /**
997 * spi_res_add - add a spi_res to the spi_message
998 * @message: the SPI message
999 * @res: the spi_resource
1000 */
spi_res_add(struct spi_message * message,void * res)1001 static void spi_res_add(struct spi_message *message, void *res)
1002 {
1003 struct spi_res *sres = container_of(res, struct spi_res, data);
1004
1005 WARN_ON(!list_empty(&sres->entry));
1006 list_add_tail(&sres->entry, &message->resources);
1007 }
1008
1009 /**
1010 * spi_res_release - release all SPI resources for this message
1011 * @ctlr: the @spi_controller
1012 * @message: the @spi_message
1013 */
spi_res_release(struct spi_controller * ctlr,struct spi_message * message)1014 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
1015 {
1016 struct spi_res *res, *tmp;
1017
1018 list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
1019 if (res->release)
1020 res->release(ctlr, message, res->data);
1021
1022 list_del(&res->entry);
1023
1024 kfree(res);
1025 }
1026 }
1027
1028 /*-------------------------------------------------------------------------*/
1029 #define spi_for_each_valid_cs(spi, idx) \
1030 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) \
1031 if (!(spi->cs_index_mask & BIT(idx))) {} else
1032
spi_is_last_cs(struct spi_device * spi)1033 static inline bool spi_is_last_cs(struct spi_device *spi)
1034 {
1035 u8 idx;
1036 bool last = false;
1037
1038 spi_for_each_valid_cs(spi, idx) {
1039 if (spi->controller->last_cs[idx] == spi_get_chipselect(spi, idx))
1040 last = true;
1041 }
1042 return last;
1043 }
1044
spi_toggle_csgpiod(struct spi_device * spi,u8 idx,bool enable,bool activate)1045 static void spi_toggle_csgpiod(struct spi_device *spi, u8 idx, bool enable, bool activate)
1046 {
1047 /*
1048 * Historically ACPI has no means of the GPIO polarity and
1049 * thus the SPISerialBus() resource defines it on the per-chip
1050 * basis. In order to avoid a chain of negations, the GPIO
1051 * polarity is considered being Active High. Even for the cases
1052 * when _DSD() is involved (in the updated versions of ACPI)
1053 * the GPIO CS polarity must be defined Active High to avoid
1054 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
1055 * into account.
1056 */
1057 if (is_acpi_device_node(dev_fwnode(&spi->dev)))
1058 gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx), !enable);
1059 else
1060 /* Polarity handled by GPIO library */
1061 gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx), activate);
1062
1063 if (activate)
1064 spi_delay_exec(&spi->cs_setup, NULL);
1065 else
1066 spi_delay_exec(&spi->cs_inactive, NULL);
1067 }
1068
spi_set_cs(struct spi_device * spi,bool enable,bool force)1069 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
1070 {
1071 bool activate = enable;
1072 u8 idx;
1073
1074 /*
1075 * Avoid calling into the driver (or doing delays) if the chip select
1076 * isn't actually changing from the last time this was called.
1077 */
1078 if (!force && ((enable && spi->controller->last_cs_index_mask == spi->cs_index_mask &&
1079 spi_is_last_cs(spi)) ||
1080 (!enable && spi->controller->last_cs_index_mask == spi->cs_index_mask &&
1081 !spi_is_last_cs(spi))) &&
1082 (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
1083 return;
1084
1085 trace_spi_set_cs(spi, activate);
1086
1087 spi->controller->last_cs_index_mask = spi->cs_index_mask;
1088 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
1089 spi->controller->last_cs[idx] = enable ? spi_get_chipselect(spi, 0) : SPI_INVALID_CS;
1090 spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
1091
1092 if (spi->mode & SPI_CS_HIGH)
1093 enable = !enable;
1094
1095 /*
1096 * Handle chip select delays for GPIO based CS or controllers without
1097 * programmable chip select timing.
1098 */
1099 if ((spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) && !activate)
1100 spi_delay_exec(&spi->cs_hold, NULL);
1101
1102 if (spi_is_csgpiod(spi)) {
1103 if (!(spi->mode & SPI_NO_CS)) {
1104 spi_for_each_valid_cs(spi, idx) {
1105 if (spi_get_csgpiod(spi, idx))
1106 spi_toggle_csgpiod(spi, idx, enable, activate);
1107 }
1108 }
1109 /* Some SPI masters need both GPIO CS & slave_select */
1110 if ((spi->controller->flags & SPI_CONTROLLER_GPIO_SS) &&
1111 spi->controller->set_cs)
1112 spi->controller->set_cs(spi, !enable);
1113 } else if (spi->controller->set_cs) {
1114 spi->controller->set_cs(spi, !enable);
1115 }
1116
1117 if (spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) {
1118 if (activate)
1119 spi_delay_exec(&spi->cs_setup, NULL);
1120 else
1121 spi_delay_exec(&spi->cs_inactive, NULL);
1122 }
1123 }
1124
1125 #ifdef CONFIG_HAS_DMA
spi_map_buf_attrs(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir,unsigned long attrs)1126 static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
1127 struct sg_table *sgt, void *buf, size_t len,
1128 enum dma_data_direction dir, unsigned long attrs)
1129 {
1130 const bool vmalloced_buf = is_vmalloc_addr(buf);
1131 unsigned int max_seg_size = dma_get_max_seg_size(dev);
1132 #ifdef CONFIG_HIGHMEM
1133 const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1134 (unsigned long)buf < (PKMAP_BASE +
1135 (LAST_PKMAP * PAGE_SIZE)));
1136 #else
1137 const bool kmap_buf = false;
1138 #endif
1139 int desc_len;
1140 int sgs;
1141 struct page *vm_page;
1142 struct scatterlist *sg;
1143 void *sg_buf;
1144 size_t min;
1145 int i, ret;
1146
1147 if (vmalloced_buf || kmap_buf) {
1148 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1149 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1150 } else if (virt_addr_valid(buf)) {
1151 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1152 sgs = DIV_ROUND_UP(len, desc_len);
1153 } else {
1154 return -EINVAL;
1155 }
1156
1157 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1158 if (ret != 0)
1159 return ret;
1160
1161 sg = &sgt->sgl[0];
1162 for (i = 0; i < sgs; i++) {
1163
1164 if (vmalloced_buf || kmap_buf) {
1165 /*
1166 * Next scatterlist entry size is the minimum between
1167 * the desc_len and the remaining buffer length that
1168 * fits in a page.
1169 */
1170 min = min_t(size_t, desc_len,
1171 min_t(size_t, len,
1172 PAGE_SIZE - offset_in_page(buf)));
1173 if (vmalloced_buf)
1174 vm_page = vmalloc_to_page(buf);
1175 else
1176 vm_page = kmap_to_page(buf);
1177 if (!vm_page) {
1178 sg_free_table(sgt);
1179 return -ENOMEM;
1180 }
1181 sg_set_page(sg, vm_page,
1182 min, offset_in_page(buf));
1183 } else {
1184 min = min_t(size_t, len, desc_len);
1185 sg_buf = buf;
1186 sg_set_buf(sg, sg_buf, min);
1187 }
1188
1189 buf += min;
1190 len -= min;
1191 sg = sg_next(sg);
1192 }
1193
1194 ret = dma_map_sgtable(dev, sgt, dir, attrs);
1195 if (ret < 0) {
1196 sg_free_table(sgt);
1197 return ret;
1198 }
1199
1200 return 0;
1201 }
1202
spi_map_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,void * buf,size_t len,enum dma_data_direction dir)1203 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1204 struct sg_table *sgt, void *buf, size_t len,
1205 enum dma_data_direction dir)
1206 {
1207 return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
1208 }
1209
spi_unmap_buf_attrs(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir,unsigned long attrs)1210 static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
1211 struct device *dev, struct sg_table *sgt,
1212 enum dma_data_direction dir,
1213 unsigned long attrs)
1214 {
1215 dma_unmap_sgtable(dev, sgt, dir, attrs);
1216 sg_free_table(sgt);
1217 sgt->orig_nents = 0;
1218 sgt->nents = 0;
1219 }
1220
spi_unmap_buf(struct spi_controller * ctlr,struct device * dev,struct sg_table * sgt,enum dma_data_direction dir)1221 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1222 struct sg_table *sgt, enum dma_data_direction dir)
1223 {
1224 spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
1225 }
1226
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1227 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1228 {
1229 struct device *tx_dev, *rx_dev;
1230 struct spi_transfer *xfer;
1231 int ret;
1232
1233 if (!ctlr->can_dma)
1234 return 0;
1235
1236 if (ctlr->dma_tx)
1237 tx_dev = ctlr->dma_tx->device->dev;
1238 else if (ctlr->dma_map_dev)
1239 tx_dev = ctlr->dma_map_dev;
1240 else
1241 tx_dev = ctlr->dev.parent;
1242
1243 if (ctlr->dma_rx)
1244 rx_dev = ctlr->dma_rx->device->dev;
1245 else if (ctlr->dma_map_dev)
1246 rx_dev = ctlr->dma_map_dev;
1247 else
1248 rx_dev = ctlr->dev.parent;
1249
1250 ret = -ENOMSG;
1251 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1252 /* The sync is done before each transfer. */
1253 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1254
1255 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1256 continue;
1257
1258 if (xfer->tx_buf != NULL) {
1259 ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1260 (void *)xfer->tx_buf,
1261 xfer->len, DMA_TO_DEVICE,
1262 attrs);
1263 if (ret != 0)
1264 return ret;
1265
1266 xfer->tx_sg_mapped = true;
1267 }
1268
1269 if (xfer->rx_buf != NULL) {
1270 ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1271 xfer->rx_buf, xfer->len,
1272 DMA_FROM_DEVICE, attrs);
1273 if (ret != 0) {
1274 spi_unmap_buf_attrs(ctlr, tx_dev,
1275 &xfer->tx_sg, DMA_TO_DEVICE,
1276 attrs);
1277
1278 return ret;
1279 }
1280
1281 xfer->rx_sg_mapped = true;
1282 }
1283 }
1284 /* No transfer has been mapped, bail out with success */
1285 if (ret)
1286 return 0;
1287
1288 ctlr->cur_rx_dma_dev = rx_dev;
1289 ctlr->cur_tx_dma_dev = tx_dev;
1290
1291 return 0;
1292 }
1293
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1294 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1295 {
1296 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1297 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1298 struct spi_transfer *xfer;
1299
1300 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1301 /* The sync has already been done after each transfer. */
1302 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1303
1304 if (xfer->rx_sg_mapped)
1305 spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1306 DMA_FROM_DEVICE, attrs);
1307 xfer->rx_sg_mapped = false;
1308
1309 if (xfer->tx_sg_mapped)
1310 spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1311 DMA_TO_DEVICE, attrs);
1312 xfer->tx_sg_mapped = false;
1313 }
1314
1315 return 0;
1316 }
1317
spi_dma_sync_for_device(struct spi_controller * ctlr,struct spi_transfer * xfer)1318 static void spi_dma_sync_for_device(struct spi_controller *ctlr,
1319 struct spi_transfer *xfer)
1320 {
1321 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1322 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1323
1324 if (xfer->tx_sg_mapped)
1325 dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1326 if (xfer->rx_sg_mapped)
1327 dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1328 }
1329
spi_dma_sync_for_cpu(struct spi_controller * ctlr,struct spi_transfer * xfer)1330 static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
1331 struct spi_transfer *xfer)
1332 {
1333 struct device *rx_dev = ctlr->cur_rx_dma_dev;
1334 struct device *tx_dev = ctlr->cur_tx_dma_dev;
1335
1336 if (xfer->rx_sg_mapped)
1337 dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1338 if (xfer->tx_sg_mapped)
1339 dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1340 }
1341 #else /* !CONFIG_HAS_DMA */
__spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1342 static inline int __spi_map_msg(struct spi_controller *ctlr,
1343 struct spi_message *msg)
1344 {
1345 return 0;
1346 }
1347
__spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1348 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1349 struct spi_message *msg)
1350 {
1351 return 0;
1352 }
1353
spi_dma_sync_for_device(struct spi_controller * ctrl,struct spi_transfer * xfer)1354 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
1355 struct spi_transfer *xfer)
1356 {
1357 }
1358
spi_dma_sync_for_cpu(struct spi_controller * ctrl,struct spi_transfer * xfer)1359 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
1360 struct spi_transfer *xfer)
1361 {
1362 }
1363 #endif /* !CONFIG_HAS_DMA */
1364
spi_unmap_msg(struct spi_controller * ctlr,struct spi_message * msg)1365 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1366 struct spi_message *msg)
1367 {
1368 struct spi_transfer *xfer;
1369
1370 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1371 /*
1372 * Restore the original value of tx_buf or rx_buf if they are
1373 * NULL.
1374 */
1375 if (xfer->tx_buf == ctlr->dummy_tx)
1376 xfer->tx_buf = NULL;
1377 if (xfer->rx_buf == ctlr->dummy_rx)
1378 xfer->rx_buf = NULL;
1379 }
1380
1381 return __spi_unmap_msg(ctlr, msg);
1382 }
1383
spi_map_msg(struct spi_controller * ctlr,struct spi_message * msg)1384 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1385 {
1386 struct spi_transfer *xfer;
1387 void *tmp;
1388 unsigned int max_tx, max_rx;
1389
1390 if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1391 && !(msg->spi->mode & SPI_3WIRE)) {
1392 max_tx = 0;
1393 max_rx = 0;
1394
1395 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1396 if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1397 !xfer->tx_buf)
1398 max_tx = max(xfer->len, max_tx);
1399 if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1400 !xfer->rx_buf)
1401 max_rx = max(xfer->len, max_rx);
1402 }
1403
1404 if (max_tx) {
1405 tmp = krealloc(ctlr->dummy_tx, max_tx,
1406 GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1407 if (!tmp)
1408 return -ENOMEM;
1409 ctlr->dummy_tx = tmp;
1410 }
1411
1412 if (max_rx) {
1413 tmp = krealloc(ctlr->dummy_rx, max_rx,
1414 GFP_KERNEL | GFP_DMA);
1415 if (!tmp)
1416 return -ENOMEM;
1417 ctlr->dummy_rx = tmp;
1418 }
1419
1420 if (max_tx || max_rx) {
1421 list_for_each_entry(xfer, &msg->transfers,
1422 transfer_list) {
1423 if (!xfer->len)
1424 continue;
1425 if (!xfer->tx_buf)
1426 xfer->tx_buf = ctlr->dummy_tx;
1427 if (!xfer->rx_buf)
1428 xfer->rx_buf = ctlr->dummy_rx;
1429 }
1430 }
1431 }
1432
1433 return __spi_map_msg(ctlr, msg);
1434 }
1435
spi_transfer_wait(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer * xfer)1436 static int spi_transfer_wait(struct spi_controller *ctlr,
1437 struct spi_message *msg,
1438 struct spi_transfer *xfer)
1439 {
1440 struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1441 struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1442 u32 speed_hz = xfer->speed_hz;
1443 unsigned long long ms;
1444
1445 if (spi_controller_is_target(ctlr)) {
1446 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1447 dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1448 return -EINTR;
1449 }
1450 } else {
1451 if (!speed_hz)
1452 speed_hz = 100000;
1453
1454 /*
1455 * For each byte we wait for 8 cycles of the SPI clock.
1456 * Since speed is defined in Hz and we want milliseconds,
1457 * use respective multiplier, but before the division,
1458 * otherwise we may get 0 for short transfers.
1459 */
1460 ms = 8LL * MSEC_PER_SEC * xfer->len;
1461 do_div(ms, speed_hz);
1462
1463 /*
1464 * Increase it twice and add 200 ms tolerance, use
1465 * predefined maximum in case of overflow.
1466 */
1467 ms += ms + 200;
1468 if (ms > UINT_MAX)
1469 ms = UINT_MAX;
1470
1471 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1472 msecs_to_jiffies(ms));
1473
1474 if (ms == 0) {
1475 SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1476 SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1477 dev_err(&msg->spi->dev,
1478 "SPI transfer timed out\n");
1479 return -ETIMEDOUT;
1480 }
1481
1482 if (xfer->error & SPI_TRANS_FAIL_IO)
1483 return -EIO;
1484 }
1485
1486 return 0;
1487 }
1488
_spi_transfer_delay_ns(u32 ns)1489 static void _spi_transfer_delay_ns(u32 ns)
1490 {
1491 if (!ns)
1492 return;
1493 if (ns <= NSEC_PER_USEC) {
1494 ndelay(ns);
1495 } else {
1496 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1497
1498 if (us <= 10)
1499 udelay(us);
1500 else
1501 usleep_range(us, us + DIV_ROUND_UP(us, 10));
1502 }
1503 }
1504
spi_delay_to_ns(struct spi_delay * _delay,struct spi_transfer * xfer)1505 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1506 {
1507 u32 delay = _delay->value;
1508 u32 unit = _delay->unit;
1509 u32 hz;
1510
1511 if (!delay)
1512 return 0;
1513
1514 switch (unit) {
1515 case SPI_DELAY_UNIT_USECS:
1516 delay *= NSEC_PER_USEC;
1517 break;
1518 case SPI_DELAY_UNIT_NSECS:
1519 /* Nothing to do here */
1520 break;
1521 case SPI_DELAY_UNIT_SCK:
1522 /* Clock cycles need to be obtained from spi_transfer */
1523 if (!xfer)
1524 return -EINVAL;
1525 /*
1526 * If there is unknown effective speed, approximate it
1527 * by underestimating with half of the requested Hz.
1528 */
1529 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1530 if (!hz)
1531 return -EINVAL;
1532
1533 /* Convert delay to nanoseconds */
1534 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1535 break;
1536 default:
1537 return -EINVAL;
1538 }
1539
1540 return delay;
1541 }
1542 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1543
spi_delay_exec(struct spi_delay * _delay,struct spi_transfer * xfer)1544 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1545 {
1546 int delay;
1547
1548 might_sleep();
1549
1550 if (!_delay)
1551 return -EINVAL;
1552
1553 delay = spi_delay_to_ns(_delay, xfer);
1554 if (delay < 0)
1555 return delay;
1556
1557 _spi_transfer_delay_ns(delay);
1558
1559 return 0;
1560 }
1561 EXPORT_SYMBOL_GPL(spi_delay_exec);
1562
_spi_transfer_cs_change_delay(struct spi_message * msg,struct spi_transfer * xfer)1563 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1564 struct spi_transfer *xfer)
1565 {
1566 u32 default_delay_ns = 10 * NSEC_PER_USEC;
1567 u32 delay = xfer->cs_change_delay.value;
1568 u32 unit = xfer->cs_change_delay.unit;
1569 int ret;
1570
1571 /* Return early on "fast" mode - for everything but USECS */
1572 if (!delay) {
1573 if (unit == SPI_DELAY_UNIT_USECS)
1574 _spi_transfer_delay_ns(default_delay_ns);
1575 return;
1576 }
1577
1578 ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1579 if (ret) {
1580 dev_err_once(&msg->spi->dev,
1581 "Use of unsupported delay unit %i, using default of %luus\n",
1582 unit, default_delay_ns / NSEC_PER_USEC);
1583 _spi_transfer_delay_ns(default_delay_ns);
1584 }
1585 }
1586
spi_transfer_cs_change_delay_exec(struct spi_message * msg,struct spi_transfer * xfer)1587 void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
1588 struct spi_transfer *xfer)
1589 {
1590 _spi_transfer_cs_change_delay(msg, xfer);
1591 }
1592 EXPORT_SYMBOL_GPL(spi_transfer_cs_change_delay_exec);
1593
1594 /*
1595 * spi_transfer_one_message - Default implementation of transfer_one_message()
1596 *
1597 * This is a standard implementation of transfer_one_message() for
1598 * drivers which implement a transfer_one() operation. It provides
1599 * standard handling of delays and chip select management.
1600 */
spi_transfer_one_message(struct spi_controller * ctlr,struct spi_message * msg)1601 static int spi_transfer_one_message(struct spi_controller *ctlr,
1602 struct spi_message *msg)
1603 {
1604 struct spi_transfer *xfer;
1605 bool keep_cs = false;
1606 int ret = 0;
1607 struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1608 struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1609
1610 xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
1611 spi_set_cs(msg->spi, !xfer->cs_off, false);
1612
1613 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1614 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1615
1616 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1617 trace_spi_transfer_start(msg, xfer);
1618
1619 spi_statistics_add_transfer_stats(statm, xfer, msg);
1620 spi_statistics_add_transfer_stats(stats, xfer, msg);
1621
1622 if (!ctlr->ptp_sts_supported) {
1623 xfer->ptp_sts_word_pre = 0;
1624 ptp_read_system_prets(xfer->ptp_sts);
1625 }
1626
1627 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1628 reinit_completion(&ctlr->xfer_completion);
1629
1630 fallback_pio:
1631 spi_dma_sync_for_device(ctlr, xfer);
1632 ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1633 if (ret < 0) {
1634 spi_dma_sync_for_cpu(ctlr, xfer);
1635
1636 if ((xfer->tx_sg_mapped || xfer->rx_sg_mapped) &&
1637 (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1638 __spi_unmap_msg(ctlr, msg);
1639 ctlr->fallback = true;
1640 xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1641 goto fallback_pio;
1642 }
1643
1644 SPI_STATISTICS_INCREMENT_FIELD(statm,
1645 errors);
1646 SPI_STATISTICS_INCREMENT_FIELD(stats,
1647 errors);
1648 dev_err(&msg->spi->dev,
1649 "SPI transfer failed: %d\n", ret);
1650 goto out;
1651 }
1652
1653 if (ret > 0) {
1654 ret = spi_transfer_wait(ctlr, msg, xfer);
1655 if (ret < 0)
1656 msg->status = ret;
1657 }
1658
1659 spi_dma_sync_for_cpu(ctlr, xfer);
1660 } else {
1661 if (xfer->len)
1662 dev_err(&msg->spi->dev,
1663 "Bufferless transfer has length %u\n",
1664 xfer->len);
1665 }
1666
1667 if (!ctlr->ptp_sts_supported) {
1668 ptp_read_system_postts(xfer->ptp_sts);
1669 xfer->ptp_sts_word_post = xfer->len;
1670 }
1671
1672 trace_spi_transfer_stop(msg, xfer);
1673
1674 if (msg->status != -EINPROGRESS)
1675 goto out;
1676
1677 spi_transfer_delay_exec(xfer);
1678
1679 if (xfer->cs_change) {
1680 if (list_is_last(&xfer->transfer_list,
1681 &msg->transfers)) {
1682 keep_cs = true;
1683 } else {
1684 if (!xfer->cs_off)
1685 spi_set_cs(msg->spi, false, false);
1686 _spi_transfer_cs_change_delay(msg, xfer);
1687 if (!list_next_entry(xfer, transfer_list)->cs_off)
1688 spi_set_cs(msg->spi, true, false);
1689 }
1690 } else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
1691 xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
1692 spi_set_cs(msg->spi, xfer->cs_off, false);
1693 }
1694
1695 msg->actual_length += xfer->len;
1696 }
1697
1698 out:
1699 if (ret != 0 || !keep_cs)
1700 spi_set_cs(msg->spi, false, false);
1701
1702 if (msg->status == -EINPROGRESS)
1703 msg->status = ret;
1704
1705 if (msg->status && ctlr->handle_err)
1706 ctlr->handle_err(ctlr, msg);
1707
1708 spi_finalize_current_message(ctlr);
1709
1710 return ret;
1711 }
1712
1713 /**
1714 * spi_finalize_current_transfer - report completion of a transfer
1715 * @ctlr: the controller reporting completion
1716 *
1717 * Called by SPI drivers using the core transfer_one_message()
1718 * implementation to notify it that the current interrupt driven
1719 * transfer has finished and the next one may be scheduled.
1720 */
spi_finalize_current_transfer(struct spi_controller * ctlr)1721 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1722 {
1723 complete(&ctlr->xfer_completion);
1724 }
1725 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1726
spi_idle_runtime_pm(struct spi_controller * ctlr)1727 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1728 {
1729 if (ctlr->auto_runtime_pm) {
1730 pm_runtime_mark_last_busy(ctlr->dev.parent);
1731 pm_runtime_put_autosuspend(ctlr->dev.parent);
1732 }
1733 }
1734
__spi_pump_transfer_message(struct spi_controller * ctlr,struct spi_message * msg,bool was_busy)1735 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1736 struct spi_message *msg, bool was_busy)
1737 {
1738 struct spi_transfer *xfer;
1739 int ret;
1740
1741 if (!was_busy && ctlr->auto_runtime_pm) {
1742 ret = pm_runtime_get_sync(ctlr->dev.parent);
1743 if (ret < 0) {
1744 pm_runtime_put_noidle(ctlr->dev.parent);
1745 dev_err(&ctlr->dev, "Failed to power device: %d\n",
1746 ret);
1747
1748 msg->status = ret;
1749 spi_finalize_current_message(ctlr);
1750
1751 return ret;
1752 }
1753 }
1754
1755 if (!was_busy)
1756 trace_spi_controller_busy(ctlr);
1757
1758 if (!was_busy && ctlr->prepare_transfer_hardware) {
1759 ret = ctlr->prepare_transfer_hardware(ctlr);
1760 if (ret) {
1761 dev_err(&ctlr->dev,
1762 "failed to prepare transfer hardware: %d\n",
1763 ret);
1764
1765 if (ctlr->auto_runtime_pm)
1766 pm_runtime_put(ctlr->dev.parent);
1767
1768 msg->status = ret;
1769 spi_finalize_current_message(ctlr);
1770
1771 return ret;
1772 }
1773 }
1774
1775 trace_spi_message_start(msg);
1776
1777 if (ctlr->prepare_message) {
1778 ret = ctlr->prepare_message(ctlr, msg);
1779 if (ret) {
1780 dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1781 ret);
1782 msg->status = ret;
1783 spi_finalize_current_message(ctlr);
1784 return ret;
1785 }
1786 msg->prepared = true;
1787 }
1788
1789 ret = spi_map_msg(ctlr, msg);
1790 if (ret) {
1791 msg->status = ret;
1792 spi_finalize_current_message(ctlr);
1793 return ret;
1794 }
1795
1796 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1797 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1798 xfer->ptp_sts_word_pre = 0;
1799 ptp_read_system_prets(xfer->ptp_sts);
1800 }
1801 }
1802
1803 /*
1804 * Drivers implementation of transfer_one_message() must arrange for
1805 * spi_finalize_current_message() to get called. Most drivers will do
1806 * this in the calling context, but some don't. For those cases, a
1807 * completion is used to guarantee that this function does not return
1808 * until spi_finalize_current_message() is done accessing
1809 * ctlr->cur_msg.
1810 * Use of the following two flags enable to opportunistically skip the
1811 * use of the completion since its use involves expensive spin locks.
1812 * In case of a race with the context that calls
1813 * spi_finalize_current_message() the completion will always be used,
1814 * due to strict ordering of these flags using barriers.
1815 */
1816 WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1817 WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1818 reinit_completion(&ctlr->cur_msg_completion);
1819 smp_wmb(); /* Make these available to spi_finalize_current_message() */
1820
1821 ret = ctlr->transfer_one_message(ctlr, msg);
1822 if (ret) {
1823 dev_err(&ctlr->dev,
1824 "failed to transfer one message from queue\n");
1825 return ret;
1826 }
1827
1828 WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1829 smp_mb(); /* See spi_finalize_current_message()... */
1830 if (READ_ONCE(ctlr->cur_msg_incomplete))
1831 wait_for_completion(&ctlr->cur_msg_completion);
1832
1833 return 0;
1834 }
1835
1836 /**
1837 * __spi_pump_messages - function which processes SPI message queue
1838 * @ctlr: controller to process queue for
1839 * @in_kthread: true if we are in the context of the message pump thread
1840 *
1841 * This function checks if there is any SPI message in the queue that
1842 * needs processing and if so call out to the driver to initialize hardware
1843 * and transfer each message.
1844 *
1845 * Note that it is called both from the kthread itself and also from
1846 * inside spi_sync(); the queue extraction handling at the top of the
1847 * function should deal with this safely.
1848 */
__spi_pump_messages(struct spi_controller * ctlr,bool in_kthread)1849 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1850 {
1851 struct spi_message *msg;
1852 bool was_busy = false;
1853 unsigned long flags;
1854 int ret;
1855
1856 /* Take the I/O mutex */
1857 mutex_lock(&ctlr->io_mutex);
1858
1859 /* Lock queue */
1860 spin_lock_irqsave(&ctlr->queue_lock, flags);
1861
1862 /* Make sure we are not already running a message */
1863 if (ctlr->cur_msg)
1864 goto out_unlock;
1865
1866 /* Check if the queue is idle */
1867 if (list_empty(&ctlr->queue) || !ctlr->running) {
1868 if (!ctlr->busy)
1869 goto out_unlock;
1870
1871 /* Defer any non-atomic teardown to the thread */
1872 if (!in_kthread) {
1873 if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1874 !ctlr->unprepare_transfer_hardware) {
1875 spi_idle_runtime_pm(ctlr);
1876 ctlr->busy = false;
1877 ctlr->queue_empty = true;
1878 trace_spi_controller_idle(ctlr);
1879 } else {
1880 kthread_queue_work(ctlr->kworker,
1881 &ctlr->pump_messages);
1882 }
1883 goto out_unlock;
1884 }
1885
1886 ctlr->busy = false;
1887 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1888
1889 kfree(ctlr->dummy_rx);
1890 ctlr->dummy_rx = NULL;
1891 kfree(ctlr->dummy_tx);
1892 ctlr->dummy_tx = NULL;
1893 if (ctlr->unprepare_transfer_hardware &&
1894 ctlr->unprepare_transfer_hardware(ctlr))
1895 dev_err(&ctlr->dev,
1896 "failed to unprepare transfer hardware\n");
1897 spi_idle_runtime_pm(ctlr);
1898 trace_spi_controller_idle(ctlr);
1899
1900 spin_lock_irqsave(&ctlr->queue_lock, flags);
1901 ctlr->queue_empty = true;
1902 goto out_unlock;
1903 }
1904
1905 /* Extract head of queue */
1906 msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1907 ctlr->cur_msg = msg;
1908
1909 list_del_init(&msg->queue);
1910 if (ctlr->busy)
1911 was_busy = true;
1912 else
1913 ctlr->busy = true;
1914 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1915
1916 ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1917 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1918
1919 ctlr->cur_msg = NULL;
1920 ctlr->fallback = false;
1921
1922 mutex_unlock(&ctlr->io_mutex);
1923
1924 /* Prod the scheduler in case transfer_one() was busy waiting */
1925 if (!ret)
1926 cond_resched();
1927 return;
1928
1929 out_unlock:
1930 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1931 mutex_unlock(&ctlr->io_mutex);
1932 }
1933
1934 /**
1935 * spi_pump_messages - kthread work function which processes spi message queue
1936 * @work: pointer to kthread work struct contained in the controller struct
1937 */
spi_pump_messages(struct kthread_work * work)1938 static void spi_pump_messages(struct kthread_work *work)
1939 {
1940 struct spi_controller *ctlr =
1941 container_of(work, struct spi_controller, pump_messages);
1942
1943 __spi_pump_messages(ctlr, true);
1944 }
1945
1946 /**
1947 * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1948 * @ctlr: Pointer to the spi_controller structure of the driver
1949 * @xfer: Pointer to the transfer being timestamped
1950 * @progress: How many words (not bytes) have been transferred so far
1951 * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1952 * transfer, for less jitter in time measurement. Only compatible
1953 * with PIO drivers. If true, must follow up with
1954 * spi_take_timestamp_post or otherwise system will crash.
1955 * WARNING: for fully predictable results, the CPU frequency must
1956 * also be under control (governor).
1957 *
1958 * This is a helper for drivers to collect the beginning of the TX timestamp
1959 * for the requested byte from the SPI transfer. The frequency with which this
1960 * function must be called (once per word, once for the whole transfer, once
1961 * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1962 * greater than or equal to the requested byte at the time of the call. The
1963 * timestamp is only taken once, at the first such call. It is assumed that
1964 * the driver advances its @tx buffer pointer monotonically.
1965 */
spi_take_timestamp_pre(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)1966 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1967 struct spi_transfer *xfer,
1968 size_t progress, bool irqs_off)
1969 {
1970 if (!xfer->ptp_sts)
1971 return;
1972
1973 if (xfer->timestamped)
1974 return;
1975
1976 if (progress > xfer->ptp_sts_word_pre)
1977 return;
1978
1979 /* Capture the resolution of the timestamp */
1980 xfer->ptp_sts_word_pre = progress;
1981
1982 if (irqs_off) {
1983 local_irq_save(ctlr->irq_flags);
1984 preempt_disable();
1985 }
1986
1987 ptp_read_system_prets(xfer->ptp_sts);
1988 }
1989 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1990
1991 /**
1992 * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1993 * @ctlr: Pointer to the spi_controller structure of the driver
1994 * @xfer: Pointer to the transfer being timestamped
1995 * @progress: How many words (not bytes) have been transferred so far
1996 * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1997 *
1998 * This is a helper for drivers to collect the end of the TX timestamp for
1999 * the requested byte from the SPI transfer. Can be called with an arbitrary
2000 * frequency: only the first call where @tx exceeds or is equal to the
2001 * requested word will be timestamped.
2002 */
spi_take_timestamp_post(struct spi_controller * ctlr,struct spi_transfer * xfer,size_t progress,bool irqs_off)2003 void spi_take_timestamp_post(struct spi_controller *ctlr,
2004 struct spi_transfer *xfer,
2005 size_t progress, bool irqs_off)
2006 {
2007 if (!xfer->ptp_sts)
2008 return;
2009
2010 if (xfer->timestamped)
2011 return;
2012
2013 if (progress < xfer->ptp_sts_word_post)
2014 return;
2015
2016 ptp_read_system_postts(xfer->ptp_sts);
2017
2018 if (irqs_off) {
2019 local_irq_restore(ctlr->irq_flags);
2020 preempt_enable();
2021 }
2022
2023 /* Capture the resolution of the timestamp */
2024 xfer->ptp_sts_word_post = progress;
2025
2026 xfer->timestamped = 1;
2027 }
2028 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
2029
2030 /**
2031 * spi_set_thread_rt - set the controller to pump at realtime priority
2032 * @ctlr: controller to boost priority of
2033 *
2034 * This can be called because the controller requested realtime priority
2035 * (by setting the ->rt value before calling spi_register_controller()) or
2036 * because a device on the bus said that its transfers needed realtime
2037 * priority.
2038 *
2039 * NOTE: at the moment if any device on a bus says it needs realtime then
2040 * the thread will be at realtime priority for all transfers on that
2041 * controller. If this eventually becomes a problem we may see if we can
2042 * find a way to boost the priority only temporarily during relevant
2043 * transfers.
2044 */
spi_set_thread_rt(struct spi_controller * ctlr)2045 static void spi_set_thread_rt(struct spi_controller *ctlr)
2046 {
2047 dev_info(&ctlr->dev,
2048 "will run message pump with realtime priority\n");
2049 sched_set_fifo(ctlr->kworker->task);
2050 }
2051
spi_init_queue(struct spi_controller * ctlr)2052 static int spi_init_queue(struct spi_controller *ctlr)
2053 {
2054 ctlr->running = false;
2055 ctlr->busy = false;
2056 ctlr->queue_empty = true;
2057
2058 ctlr->kworker = kthread_run_worker(0, dev_name(&ctlr->dev));
2059 if (IS_ERR(ctlr->kworker)) {
2060 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
2061 return PTR_ERR(ctlr->kworker);
2062 }
2063
2064 kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
2065
2066 /*
2067 * Controller config will indicate if this controller should run the
2068 * message pump with high (realtime) priority to reduce the transfer
2069 * latency on the bus by minimising the delay between a transfer
2070 * request and the scheduling of the message pump thread. Without this
2071 * setting the message pump thread will remain at default priority.
2072 */
2073 if (ctlr->rt)
2074 spi_set_thread_rt(ctlr);
2075
2076 return 0;
2077 }
2078
2079 /**
2080 * spi_get_next_queued_message() - called by driver to check for queued
2081 * messages
2082 * @ctlr: the controller to check for queued messages
2083 *
2084 * If there are more messages in the queue, the next message is returned from
2085 * this call.
2086 *
2087 * Return: the next message in the queue, else NULL if the queue is empty.
2088 */
spi_get_next_queued_message(struct spi_controller * ctlr)2089 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
2090 {
2091 struct spi_message *next;
2092 unsigned long flags;
2093
2094 /* Get a pointer to the next message, if any */
2095 spin_lock_irqsave(&ctlr->queue_lock, flags);
2096 next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
2097 queue);
2098 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2099
2100 return next;
2101 }
2102 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
2103
2104 /*
2105 * __spi_unoptimize_message - shared implementation of spi_unoptimize_message()
2106 * and spi_maybe_unoptimize_message()
2107 * @msg: the message to unoptimize
2108 *
2109 * Peripheral drivers should use spi_unoptimize_message() and callers inside
2110 * core should use spi_maybe_unoptimize_message() rather than calling this
2111 * function directly.
2112 *
2113 * It is not valid to call this on a message that is not currently optimized.
2114 */
__spi_unoptimize_message(struct spi_message * msg)2115 static void __spi_unoptimize_message(struct spi_message *msg)
2116 {
2117 struct spi_controller *ctlr = msg->spi->controller;
2118
2119 if (ctlr->unoptimize_message)
2120 ctlr->unoptimize_message(msg);
2121
2122 spi_res_release(ctlr, msg);
2123
2124 msg->optimized = false;
2125 msg->opt_state = NULL;
2126 }
2127
2128 /*
2129 * spi_maybe_unoptimize_message - unoptimize msg not managed by a peripheral
2130 * @msg: the message to unoptimize
2131 *
2132 * This function is used to unoptimize a message if and only if it was
2133 * optimized by the core (via spi_maybe_optimize_message()).
2134 */
spi_maybe_unoptimize_message(struct spi_message * msg)2135 static void spi_maybe_unoptimize_message(struct spi_message *msg)
2136 {
2137 if (!msg->pre_optimized && msg->optimized &&
2138 !msg->spi->controller->defer_optimize_message)
2139 __spi_unoptimize_message(msg);
2140 }
2141
2142 /**
2143 * spi_finalize_current_message() - the current message is complete
2144 * @ctlr: the controller to return the message to
2145 *
2146 * Called by the driver to notify the core that the message in the front of the
2147 * queue is complete and can be removed from the queue.
2148 */
spi_finalize_current_message(struct spi_controller * ctlr)2149 void spi_finalize_current_message(struct spi_controller *ctlr)
2150 {
2151 struct spi_transfer *xfer;
2152 struct spi_message *mesg;
2153 int ret;
2154
2155 mesg = ctlr->cur_msg;
2156
2157 if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
2158 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
2159 ptp_read_system_postts(xfer->ptp_sts);
2160 xfer->ptp_sts_word_post = xfer->len;
2161 }
2162 }
2163
2164 if (unlikely(ctlr->ptp_sts_supported))
2165 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
2166 WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
2167
2168 spi_unmap_msg(ctlr, mesg);
2169
2170 if (mesg->prepared && ctlr->unprepare_message) {
2171 ret = ctlr->unprepare_message(ctlr, mesg);
2172 if (ret) {
2173 dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
2174 ret);
2175 }
2176 }
2177
2178 mesg->prepared = false;
2179
2180 spi_maybe_unoptimize_message(mesg);
2181
2182 WRITE_ONCE(ctlr->cur_msg_incomplete, false);
2183 smp_mb(); /* See __spi_pump_transfer_message()... */
2184 if (READ_ONCE(ctlr->cur_msg_need_completion))
2185 complete(&ctlr->cur_msg_completion);
2186
2187 trace_spi_message_done(mesg);
2188
2189 mesg->state = NULL;
2190 if (mesg->complete)
2191 mesg->complete(mesg->context);
2192 }
2193 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
2194
spi_start_queue(struct spi_controller * ctlr)2195 static int spi_start_queue(struct spi_controller *ctlr)
2196 {
2197 unsigned long flags;
2198
2199 spin_lock_irqsave(&ctlr->queue_lock, flags);
2200
2201 if (ctlr->running || ctlr->busy) {
2202 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2203 return -EBUSY;
2204 }
2205
2206 ctlr->running = true;
2207 ctlr->cur_msg = NULL;
2208 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2209
2210 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2211
2212 return 0;
2213 }
2214
spi_stop_queue(struct spi_controller * ctlr)2215 static int spi_stop_queue(struct spi_controller *ctlr)
2216 {
2217 unsigned int limit = 500;
2218 unsigned long flags;
2219
2220 /*
2221 * This is a bit lame, but is optimized for the common execution path.
2222 * A wait_queue on the ctlr->busy could be used, but then the common
2223 * execution path (pump_messages) would be required to call wake_up or
2224 * friends on every SPI message. Do this instead.
2225 */
2226 do {
2227 spin_lock_irqsave(&ctlr->queue_lock, flags);
2228 if (list_empty(&ctlr->queue) && !ctlr->busy) {
2229 ctlr->running = false;
2230 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2231 return 0;
2232 }
2233 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2234 usleep_range(10000, 11000);
2235 } while (--limit);
2236
2237 return -EBUSY;
2238 }
2239
spi_destroy_queue(struct spi_controller * ctlr)2240 static int spi_destroy_queue(struct spi_controller *ctlr)
2241 {
2242 int ret;
2243
2244 ret = spi_stop_queue(ctlr);
2245
2246 /*
2247 * kthread_flush_worker will block until all work is done.
2248 * If the reason that stop_queue timed out is that the work will never
2249 * finish, then it does no good to call flush/stop thread, so
2250 * return anyway.
2251 */
2252 if (ret) {
2253 dev_err(&ctlr->dev, "problem destroying queue\n");
2254 return ret;
2255 }
2256
2257 kthread_destroy_worker(ctlr->kworker);
2258
2259 return 0;
2260 }
2261
__spi_queued_transfer(struct spi_device * spi,struct spi_message * msg,bool need_pump)2262 static int __spi_queued_transfer(struct spi_device *spi,
2263 struct spi_message *msg,
2264 bool need_pump)
2265 {
2266 struct spi_controller *ctlr = spi->controller;
2267 unsigned long flags;
2268
2269 spin_lock_irqsave(&ctlr->queue_lock, flags);
2270
2271 if (!ctlr->running) {
2272 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2273 return -ESHUTDOWN;
2274 }
2275 msg->actual_length = 0;
2276 msg->status = -EINPROGRESS;
2277
2278 list_add_tail(&msg->queue, &ctlr->queue);
2279 ctlr->queue_empty = false;
2280 if (!ctlr->busy && need_pump)
2281 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2282
2283 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2284 return 0;
2285 }
2286
2287 /**
2288 * spi_queued_transfer - transfer function for queued transfers
2289 * @spi: SPI device which is requesting transfer
2290 * @msg: SPI message which is to handled is queued to driver queue
2291 *
2292 * Return: zero on success, else a negative error code.
2293 */
spi_queued_transfer(struct spi_device * spi,struct spi_message * msg)2294 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2295 {
2296 return __spi_queued_transfer(spi, msg, true);
2297 }
2298
spi_controller_initialize_queue(struct spi_controller * ctlr)2299 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2300 {
2301 int ret;
2302
2303 ctlr->transfer = spi_queued_transfer;
2304 if (!ctlr->transfer_one_message)
2305 ctlr->transfer_one_message = spi_transfer_one_message;
2306
2307 /* Initialize and start queue */
2308 ret = spi_init_queue(ctlr);
2309 if (ret) {
2310 dev_err(&ctlr->dev, "problem initializing queue\n");
2311 goto err_init_queue;
2312 }
2313 ctlr->queued = true;
2314 ret = spi_start_queue(ctlr);
2315 if (ret) {
2316 dev_err(&ctlr->dev, "problem starting queue\n");
2317 goto err_start_queue;
2318 }
2319
2320 return 0;
2321
2322 err_start_queue:
2323 spi_destroy_queue(ctlr);
2324 err_init_queue:
2325 return ret;
2326 }
2327
2328 /**
2329 * spi_flush_queue - Send all pending messages in the queue from the callers'
2330 * context
2331 * @ctlr: controller to process queue for
2332 *
2333 * This should be used when one wants to ensure all pending messages have been
2334 * sent before doing something. Is used by the spi-mem code to make sure SPI
2335 * memory operations do not preempt regular SPI transfers that have been queued
2336 * before the spi-mem operation.
2337 */
spi_flush_queue(struct spi_controller * ctlr)2338 void spi_flush_queue(struct spi_controller *ctlr)
2339 {
2340 if (ctlr->transfer == spi_queued_transfer)
2341 __spi_pump_messages(ctlr, false);
2342 }
2343
2344 /*-------------------------------------------------------------------------*/
2345
2346 #if defined(CONFIG_OF)
of_spi_parse_dt_cs_delay(struct device_node * nc,struct spi_delay * delay,const char * prop)2347 static void of_spi_parse_dt_cs_delay(struct device_node *nc,
2348 struct spi_delay *delay, const char *prop)
2349 {
2350 u32 value;
2351
2352 if (!of_property_read_u32(nc, prop, &value)) {
2353 if (value > U16_MAX) {
2354 delay->value = DIV_ROUND_UP(value, 1000);
2355 delay->unit = SPI_DELAY_UNIT_USECS;
2356 } else {
2357 delay->value = value;
2358 delay->unit = SPI_DELAY_UNIT_NSECS;
2359 }
2360 }
2361 }
2362
of_spi_parse_dt(struct spi_controller * ctlr,struct spi_device * spi,struct device_node * nc)2363 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2364 struct device_node *nc)
2365 {
2366 u32 value, cs[SPI_CS_CNT_MAX];
2367 int rc, idx;
2368
2369 /* Mode (clock phase/polarity/etc.) */
2370 if (of_property_read_bool(nc, "spi-cpha"))
2371 spi->mode |= SPI_CPHA;
2372 if (of_property_read_bool(nc, "spi-cpol"))
2373 spi->mode |= SPI_CPOL;
2374 if (of_property_read_bool(nc, "spi-3wire"))
2375 spi->mode |= SPI_3WIRE;
2376 if (of_property_read_bool(nc, "spi-lsb-first"))
2377 spi->mode |= SPI_LSB_FIRST;
2378 if (of_property_read_bool(nc, "spi-cs-high"))
2379 spi->mode |= SPI_CS_HIGH;
2380
2381 /* Device DUAL/QUAD mode */
2382 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2383 switch (value) {
2384 case 0:
2385 spi->mode |= SPI_NO_TX;
2386 break;
2387 case 1:
2388 break;
2389 case 2:
2390 spi->mode |= SPI_TX_DUAL;
2391 break;
2392 case 4:
2393 spi->mode |= SPI_TX_QUAD;
2394 break;
2395 case 8:
2396 spi->mode |= SPI_TX_OCTAL;
2397 break;
2398 default:
2399 dev_warn(&ctlr->dev,
2400 "spi-tx-bus-width %d not supported\n",
2401 value);
2402 break;
2403 }
2404 }
2405
2406 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2407 switch (value) {
2408 case 0:
2409 spi->mode |= SPI_NO_RX;
2410 break;
2411 case 1:
2412 break;
2413 case 2:
2414 spi->mode |= SPI_RX_DUAL;
2415 break;
2416 case 4:
2417 spi->mode |= SPI_RX_QUAD;
2418 break;
2419 case 8:
2420 spi->mode |= SPI_RX_OCTAL;
2421 break;
2422 default:
2423 dev_warn(&ctlr->dev,
2424 "spi-rx-bus-width %d not supported\n",
2425 value);
2426 break;
2427 }
2428 }
2429
2430 if (spi_controller_is_target(ctlr)) {
2431 if (!of_node_name_eq(nc, "slave")) {
2432 dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2433 nc);
2434 return -EINVAL;
2435 }
2436 return 0;
2437 }
2438
2439 if (ctlr->num_chipselect > SPI_CS_CNT_MAX) {
2440 dev_err(&ctlr->dev, "No. of CS is more than max. no. of supported CS\n");
2441 return -EINVAL;
2442 }
2443
2444 spi_set_all_cs_unused(spi);
2445
2446 /* Device address */
2447 rc = of_property_read_variable_u32_array(nc, "reg", &cs[0], 1,
2448 SPI_CS_CNT_MAX);
2449 if (rc < 0) {
2450 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2451 nc, rc);
2452 return rc;
2453 }
2454 if (rc > ctlr->num_chipselect) {
2455 dev_err(&ctlr->dev, "%pOF has number of CS > ctlr->num_chipselect (%d)\n",
2456 nc, rc);
2457 return rc;
2458 }
2459 if ((of_property_present(nc, "parallel-memories")) &&
2460 (!(ctlr->flags & SPI_CONTROLLER_MULTI_CS))) {
2461 dev_err(&ctlr->dev, "SPI controller doesn't support multi CS\n");
2462 return -EINVAL;
2463 }
2464 for (idx = 0; idx < rc; idx++)
2465 spi_set_chipselect(spi, idx, cs[idx]);
2466
2467 /*
2468 * By default spi->chip_select[0] will hold the physical CS number,
2469 * so set bit 0 in spi->cs_index_mask.
2470 */
2471 spi->cs_index_mask = BIT(0);
2472
2473 /* Device speed */
2474 if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2475 spi->max_speed_hz = value;
2476
2477 /* Device CS delays */
2478 of_spi_parse_dt_cs_delay(nc, &spi->cs_setup, "spi-cs-setup-delay-ns");
2479 of_spi_parse_dt_cs_delay(nc, &spi->cs_hold, "spi-cs-hold-delay-ns");
2480 of_spi_parse_dt_cs_delay(nc, &spi->cs_inactive, "spi-cs-inactive-delay-ns");
2481
2482 return 0;
2483 }
2484
2485 static struct spi_device *
of_register_spi_device(struct spi_controller * ctlr,struct device_node * nc)2486 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2487 {
2488 struct spi_device *spi;
2489 int rc;
2490
2491 /* Alloc an spi_device */
2492 spi = spi_alloc_device(ctlr);
2493 if (!spi) {
2494 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2495 rc = -ENOMEM;
2496 goto err_out;
2497 }
2498
2499 /* Select device driver */
2500 rc = of_alias_from_compatible(nc, spi->modalias,
2501 sizeof(spi->modalias));
2502 if (rc < 0) {
2503 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2504 goto err_out;
2505 }
2506
2507 rc = of_spi_parse_dt(ctlr, spi, nc);
2508 if (rc)
2509 goto err_out;
2510
2511 /* Store a pointer to the node in the device structure */
2512 of_node_get(nc);
2513
2514 device_set_node(&spi->dev, of_fwnode_handle(nc));
2515
2516 /* Register the new device */
2517 rc = spi_add_device(spi);
2518 if (rc) {
2519 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2520 goto err_of_node_put;
2521 }
2522
2523 return spi;
2524
2525 err_of_node_put:
2526 of_node_put(nc);
2527 err_out:
2528 spi_dev_put(spi);
2529 return ERR_PTR(rc);
2530 }
2531
2532 /**
2533 * of_register_spi_devices() - Register child devices onto the SPI bus
2534 * @ctlr: Pointer to spi_controller device
2535 *
2536 * Registers an spi_device for each child node of controller node which
2537 * represents a valid SPI slave.
2538 */
of_register_spi_devices(struct spi_controller * ctlr)2539 static void of_register_spi_devices(struct spi_controller *ctlr)
2540 {
2541 struct spi_device *spi;
2542 struct device_node *nc;
2543
2544 for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2545 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2546 continue;
2547 spi = of_register_spi_device(ctlr, nc);
2548 if (IS_ERR(spi)) {
2549 dev_warn(&ctlr->dev,
2550 "Failed to create SPI device for %pOF\n", nc);
2551 of_node_clear_flag(nc, OF_POPULATED);
2552 }
2553 }
2554 }
2555 #else
of_register_spi_devices(struct spi_controller * ctlr)2556 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2557 #endif
2558
2559 /**
2560 * spi_new_ancillary_device() - Register ancillary SPI device
2561 * @spi: Pointer to the main SPI device registering the ancillary device
2562 * @chip_select: Chip Select of the ancillary device
2563 *
2564 * Register an ancillary SPI device; for example some chips have a chip-select
2565 * for normal device usage and another one for setup/firmware upload.
2566 *
2567 * This may only be called from main SPI device's probe routine.
2568 *
2569 * Return: 0 on success; negative errno on failure
2570 */
spi_new_ancillary_device(struct spi_device * spi,u8 chip_select)2571 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2572 u8 chip_select)
2573 {
2574 struct spi_controller *ctlr = spi->controller;
2575 struct spi_device *ancillary;
2576 int rc;
2577
2578 /* Alloc an spi_device */
2579 ancillary = spi_alloc_device(ctlr);
2580 if (!ancillary) {
2581 rc = -ENOMEM;
2582 goto err_out;
2583 }
2584
2585 strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2586
2587 /* Use provided chip-select for ancillary device */
2588 spi_set_all_cs_unused(ancillary);
2589 spi_set_chipselect(ancillary, 0, chip_select);
2590
2591 /* Take over SPI mode/speed from SPI main device */
2592 ancillary->max_speed_hz = spi->max_speed_hz;
2593 ancillary->mode = spi->mode;
2594 /*
2595 * By default spi->chip_select[0] will hold the physical CS number,
2596 * so set bit 0 in spi->cs_index_mask.
2597 */
2598 ancillary->cs_index_mask = BIT(0);
2599
2600 WARN_ON(!mutex_is_locked(&ctlr->add_lock));
2601
2602 /* Register the new device */
2603 rc = __spi_add_device(ancillary);
2604 if (rc) {
2605 dev_err(&spi->dev, "failed to register ancillary device\n");
2606 goto err_out;
2607 }
2608
2609 return ancillary;
2610
2611 err_out:
2612 spi_dev_put(ancillary);
2613 return ERR_PTR(rc);
2614 }
2615 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2616
2617 #ifdef CONFIG_ACPI
2618 struct acpi_spi_lookup {
2619 struct spi_controller *ctlr;
2620 u32 max_speed_hz;
2621 u32 mode;
2622 int irq;
2623 u8 bits_per_word;
2624 u8 chip_select;
2625 int n;
2626 int index;
2627 };
2628
acpi_spi_count(struct acpi_resource * ares,void * data)2629 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2630 {
2631 struct acpi_resource_spi_serialbus *sb;
2632 int *count = data;
2633
2634 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2635 return 1;
2636
2637 sb = &ares->data.spi_serial_bus;
2638 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2639 return 1;
2640
2641 *count = *count + 1;
2642
2643 return 1;
2644 }
2645
2646 /**
2647 * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2648 * @adev: ACPI device
2649 *
2650 * Return: the number of SpiSerialBus resources in the ACPI-device's
2651 * resource-list; or a negative error code.
2652 */
acpi_spi_count_resources(struct acpi_device * adev)2653 int acpi_spi_count_resources(struct acpi_device *adev)
2654 {
2655 LIST_HEAD(r);
2656 int count = 0;
2657 int ret;
2658
2659 ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2660 if (ret < 0)
2661 return ret;
2662
2663 acpi_dev_free_resource_list(&r);
2664
2665 return count;
2666 }
2667 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2668
acpi_spi_parse_apple_properties(struct acpi_device * dev,struct acpi_spi_lookup * lookup)2669 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2670 struct acpi_spi_lookup *lookup)
2671 {
2672 const union acpi_object *obj;
2673
2674 if (!x86_apple_machine)
2675 return;
2676
2677 if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2678 && obj->buffer.length >= 4)
2679 lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2680
2681 if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2682 && obj->buffer.length == 8)
2683 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2684
2685 if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2686 && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2687 lookup->mode |= SPI_LSB_FIRST;
2688
2689 if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2690 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2691 lookup->mode |= SPI_CPOL;
2692
2693 if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2694 && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
2695 lookup->mode |= SPI_CPHA;
2696 }
2697
acpi_spi_add_resource(struct acpi_resource * ares,void * data)2698 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2699 {
2700 struct acpi_spi_lookup *lookup = data;
2701 struct spi_controller *ctlr = lookup->ctlr;
2702
2703 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2704 struct acpi_resource_spi_serialbus *sb;
2705 acpi_handle parent_handle;
2706 acpi_status status;
2707
2708 sb = &ares->data.spi_serial_bus;
2709 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2710
2711 if (lookup->index != -1 && lookup->n++ != lookup->index)
2712 return 1;
2713
2714 status = acpi_get_handle(NULL,
2715 sb->resource_source.string_ptr,
2716 &parent_handle);
2717
2718 if (ACPI_FAILURE(status))
2719 return -ENODEV;
2720
2721 if (ctlr) {
2722 if (!device_match_acpi_handle(ctlr->dev.parent, parent_handle))
2723 return -ENODEV;
2724 } else {
2725 struct acpi_device *adev;
2726
2727 adev = acpi_fetch_acpi_dev(parent_handle);
2728 if (!adev)
2729 return -ENODEV;
2730
2731 ctlr = acpi_spi_find_controller_by_adev(adev);
2732 if (!ctlr)
2733 return -EPROBE_DEFER;
2734
2735 lookup->ctlr = ctlr;
2736 }
2737
2738 /*
2739 * ACPI DeviceSelection numbering is handled by the
2740 * host controller driver in Windows and can vary
2741 * from driver to driver. In Linux we always expect
2742 * 0 .. max - 1 so we need to ask the driver to
2743 * translate between the two schemes.
2744 */
2745 if (ctlr->fw_translate_cs) {
2746 int cs = ctlr->fw_translate_cs(ctlr,
2747 sb->device_selection);
2748 if (cs < 0)
2749 return cs;
2750 lookup->chip_select = cs;
2751 } else {
2752 lookup->chip_select = sb->device_selection;
2753 }
2754
2755 lookup->max_speed_hz = sb->connection_speed;
2756 lookup->bits_per_word = sb->data_bit_length;
2757
2758 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2759 lookup->mode |= SPI_CPHA;
2760 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2761 lookup->mode |= SPI_CPOL;
2762 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2763 lookup->mode |= SPI_CS_HIGH;
2764 }
2765 } else if (lookup->irq < 0) {
2766 struct resource r;
2767
2768 if (acpi_dev_resource_interrupt(ares, 0, &r))
2769 lookup->irq = r.start;
2770 }
2771
2772 /* Always tell the ACPI core to skip this resource */
2773 return 1;
2774 }
2775
2776 /**
2777 * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2778 * @ctlr: controller to which the spi device belongs
2779 * @adev: ACPI Device for the spi device
2780 * @index: Index of the spi resource inside the ACPI Node
2781 *
2782 * This should be used to allocate a new SPI device from and ACPI Device node.
2783 * The caller is responsible for calling spi_add_device to register the SPI device.
2784 *
2785 * If ctlr is set to NULL, the Controller for the SPI device will be looked up
2786 * using the resource.
2787 * If index is set to -1, index is not used.
2788 * Note: If index is -1, ctlr must be set.
2789 *
2790 * Return: a pointer to the new device, or ERR_PTR on error.
2791 */
acpi_spi_device_alloc(struct spi_controller * ctlr,struct acpi_device * adev,int index)2792 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2793 struct acpi_device *adev,
2794 int index)
2795 {
2796 acpi_handle parent_handle = NULL;
2797 struct list_head resource_list;
2798 struct acpi_spi_lookup lookup = {};
2799 struct spi_device *spi;
2800 int ret;
2801
2802 if (!ctlr && index == -1)
2803 return ERR_PTR(-EINVAL);
2804
2805 lookup.ctlr = ctlr;
2806 lookup.irq = -1;
2807 lookup.index = index;
2808 lookup.n = 0;
2809
2810 INIT_LIST_HEAD(&resource_list);
2811 ret = acpi_dev_get_resources(adev, &resource_list,
2812 acpi_spi_add_resource, &lookup);
2813 acpi_dev_free_resource_list(&resource_list);
2814
2815 if (ret < 0)
2816 /* Found SPI in _CRS but it points to another controller */
2817 return ERR_PTR(ret);
2818
2819 if (!lookup.max_speed_hz &&
2820 ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2821 device_match_acpi_handle(lookup.ctlr->dev.parent, parent_handle)) {
2822 /* Apple does not use _CRS but nested devices for SPI slaves */
2823 acpi_spi_parse_apple_properties(adev, &lookup);
2824 }
2825
2826 if (!lookup.max_speed_hz)
2827 return ERR_PTR(-ENODEV);
2828
2829 spi = spi_alloc_device(lookup.ctlr);
2830 if (!spi) {
2831 dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2832 dev_name(&adev->dev));
2833 return ERR_PTR(-ENOMEM);
2834 }
2835
2836 spi_set_all_cs_unused(spi);
2837 spi_set_chipselect(spi, 0, lookup.chip_select);
2838
2839 ACPI_COMPANION_SET(&spi->dev, adev);
2840 spi->max_speed_hz = lookup.max_speed_hz;
2841 spi->mode |= lookup.mode;
2842 spi->irq = lookup.irq;
2843 spi->bits_per_word = lookup.bits_per_word;
2844 /*
2845 * By default spi->chip_select[0] will hold the physical CS number,
2846 * so set bit 0 in spi->cs_index_mask.
2847 */
2848 spi->cs_index_mask = BIT(0);
2849
2850 return spi;
2851 }
2852 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2853
acpi_register_spi_device(struct spi_controller * ctlr,struct acpi_device * adev)2854 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2855 struct acpi_device *adev)
2856 {
2857 struct spi_device *spi;
2858
2859 if (acpi_bus_get_status(adev) || !adev->status.present ||
2860 acpi_device_enumerated(adev))
2861 return AE_OK;
2862
2863 spi = acpi_spi_device_alloc(ctlr, adev, -1);
2864 if (IS_ERR(spi)) {
2865 if (PTR_ERR(spi) == -ENOMEM)
2866 return AE_NO_MEMORY;
2867 else
2868 return AE_OK;
2869 }
2870
2871 acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2872 sizeof(spi->modalias));
2873
2874 acpi_device_set_enumerated(adev);
2875
2876 adev->power.flags.ignore_parent = true;
2877 if (spi_add_device(spi)) {
2878 adev->power.flags.ignore_parent = false;
2879 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2880 dev_name(&adev->dev));
2881 spi_dev_put(spi);
2882 }
2883
2884 return AE_OK;
2885 }
2886
acpi_spi_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)2887 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2888 void *data, void **return_value)
2889 {
2890 struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2891 struct spi_controller *ctlr = data;
2892
2893 if (!adev)
2894 return AE_OK;
2895
2896 return acpi_register_spi_device(ctlr, adev);
2897 }
2898
2899 #define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
2900
acpi_register_spi_devices(struct spi_controller * ctlr)2901 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2902 {
2903 acpi_status status;
2904 acpi_handle handle;
2905
2906 handle = ACPI_HANDLE(ctlr->dev.parent);
2907 if (!handle)
2908 return;
2909
2910 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2911 SPI_ACPI_ENUMERATE_MAX_DEPTH,
2912 acpi_spi_add_device, NULL, ctlr, NULL);
2913 if (ACPI_FAILURE(status))
2914 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2915 }
2916 #else
acpi_register_spi_devices(struct spi_controller * ctlr)2917 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2918 #endif /* CONFIG_ACPI */
2919
spi_controller_release(struct device * dev)2920 static void spi_controller_release(struct device *dev)
2921 {
2922 struct spi_controller *ctlr;
2923
2924 ctlr = container_of(dev, struct spi_controller, dev);
2925 kfree(ctlr);
2926 }
2927
2928 static const struct class spi_master_class = {
2929 .name = "spi_master",
2930 .dev_release = spi_controller_release,
2931 .dev_groups = spi_master_groups,
2932 };
2933
2934 #ifdef CONFIG_SPI_SLAVE
2935 /**
2936 * spi_target_abort - abort the ongoing transfer request on an SPI slave
2937 * controller
2938 * @spi: device used for the current transfer
2939 */
spi_target_abort(struct spi_device * spi)2940 int spi_target_abort(struct spi_device *spi)
2941 {
2942 struct spi_controller *ctlr = spi->controller;
2943
2944 if (spi_controller_is_target(ctlr) && ctlr->target_abort)
2945 return ctlr->target_abort(ctlr);
2946
2947 return -ENOTSUPP;
2948 }
2949 EXPORT_SYMBOL_GPL(spi_target_abort);
2950
slave_show(struct device * dev,struct device_attribute * attr,char * buf)2951 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2952 char *buf)
2953 {
2954 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2955 dev);
2956 struct device *child;
2957 int ret;
2958
2959 child = device_find_any_child(&ctlr->dev);
2960 ret = sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias : NULL);
2961 put_device(child);
2962
2963 return ret;
2964 }
2965
slave_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2966 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2967 const char *buf, size_t count)
2968 {
2969 struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2970 dev);
2971 struct spi_device *spi;
2972 struct device *child;
2973 char name[32];
2974 int rc;
2975
2976 rc = sscanf(buf, "%31s", name);
2977 if (rc != 1 || !name[0])
2978 return -EINVAL;
2979
2980 child = device_find_any_child(&ctlr->dev);
2981 if (child) {
2982 /* Remove registered slave */
2983 device_unregister(child);
2984 put_device(child);
2985 }
2986
2987 if (strcmp(name, "(null)")) {
2988 /* Register new slave */
2989 spi = spi_alloc_device(ctlr);
2990 if (!spi)
2991 return -ENOMEM;
2992
2993 strscpy(spi->modalias, name, sizeof(spi->modalias));
2994
2995 rc = spi_add_device(spi);
2996 if (rc) {
2997 spi_dev_put(spi);
2998 return rc;
2999 }
3000 }
3001
3002 return count;
3003 }
3004
3005 static DEVICE_ATTR_RW(slave);
3006
3007 static struct attribute *spi_slave_attrs[] = {
3008 &dev_attr_slave.attr,
3009 NULL,
3010 };
3011
3012 static const struct attribute_group spi_slave_group = {
3013 .attrs = spi_slave_attrs,
3014 };
3015
3016 static const struct attribute_group *spi_slave_groups[] = {
3017 &spi_controller_statistics_group,
3018 &spi_slave_group,
3019 NULL,
3020 };
3021
3022 static const struct class spi_slave_class = {
3023 .name = "spi_slave",
3024 .dev_release = spi_controller_release,
3025 .dev_groups = spi_slave_groups,
3026 };
3027 #else
3028 extern struct class spi_slave_class; /* dummy */
3029 #endif
3030
3031 /**
3032 * __spi_alloc_controller - allocate an SPI master or slave controller
3033 * @dev: the controller, possibly using the platform_bus
3034 * @size: how much zeroed driver-private data to allocate; the pointer to this
3035 * memory is in the driver_data field of the returned device, accessible
3036 * with spi_controller_get_devdata(); the memory is cacheline aligned;
3037 * drivers granting DMA access to portions of their private data need to
3038 * round up @size using ALIGN(size, dma_get_cache_alignment()).
3039 * @slave: flag indicating whether to allocate an SPI master (false) or SPI
3040 * slave (true) controller
3041 * Context: can sleep
3042 *
3043 * This call is used only by SPI controller drivers, which are the
3044 * only ones directly touching chip registers. It's how they allocate
3045 * an spi_controller structure, prior to calling spi_register_controller().
3046 *
3047 * This must be called from context that can sleep.
3048 *
3049 * The caller is responsible for assigning the bus number and initializing the
3050 * controller's methods before calling spi_register_controller(); and (after
3051 * errors adding the device) calling spi_controller_put() to prevent a memory
3052 * leak.
3053 *
3054 * Return: the SPI controller structure on success, else NULL.
3055 */
__spi_alloc_controller(struct device * dev,unsigned int size,bool slave)3056 struct spi_controller *__spi_alloc_controller(struct device *dev,
3057 unsigned int size, bool slave)
3058 {
3059 struct spi_controller *ctlr;
3060 size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
3061
3062 if (!dev)
3063 return NULL;
3064
3065 ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
3066 if (!ctlr)
3067 return NULL;
3068
3069 device_initialize(&ctlr->dev);
3070 INIT_LIST_HEAD(&ctlr->queue);
3071 spin_lock_init(&ctlr->queue_lock);
3072 spin_lock_init(&ctlr->bus_lock_spinlock);
3073 mutex_init(&ctlr->bus_lock_mutex);
3074 mutex_init(&ctlr->io_mutex);
3075 mutex_init(&ctlr->add_lock);
3076 ctlr->bus_num = -1;
3077 ctlr->num_chipselect = 1;
3078 ctlr->slave = slave;
3079 if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
3080 ctlr->dev.class = &spi_slave_class;
3081 else
3082 ctlr->dev.class = &spi_master_class;
3083 ctlr->dev.parent = dev;
3084 pm_suspend_ignore_children(&ctlr->dev, true);
3085 spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
3086
3087 return ctlr;
3088 }
3089 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
3090
devm_spi_release_controller(struct device * dev,void * ctlr)3091 static void devm_spi_release_controller(struct device *dev, void *ctlr)
3092 {
3093 spi_controller_put(*(struct spi_controller **)ctlr);
3094 }
3095
3096 /**
3097 * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
3098 * @dev: physical device of SPI controller
3099 * @size: how much zeroed driver-private data to allocate
3100 * @slave: whether to allocate an SPI master (false) or SPI slave (true)
3101 * Context: can sleep
3102 *
3103 * Allocate an SPI controller and automatically release a reference on it
3104 * when @dev is unbound from its driver. Drivers are thus relieved from
3105 * having to call spi_controller_put().
3106 *
3107 * The arguments to this function are identical to __spi_alloc_controller().
3108 *
3109 * Return: the SPI controller structure on success, else NULL.
3110 */
__devm_spi_alloc_controller(struct device * dev,unsigned int size,bool slave)3111 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
3112 unsigned int size,
3113 bool slave)
3114 {
3115 struct spi_controller **ptr, *ctlr;
3116
3117 ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
3118 GFP_KERNEL);
3119 if (!ptr)
3120 return NULL;
3121
3122 ctlr = __spi_alloc_controller(dev, size, slave);
3123 if (ctlr) {
3124 ctlr->devm_allocated = true;
3125 *ptr = ctlr;
3126 devres_add(dev, ptr);
3127 } else {
3128 devres_free(ptr);
3129 }
3130
3131 return ctlr;
3132 }
3133 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
3134
3135 /**
3136 * spi_get_gpio_descs() - grab chip select GPIOs for the master
3137 * @ctlr: The SPI master to grab GPIO descriptors for
3138 */
spi_get_gpio_descs(struct spi_controller * ctlr)3139 static int spi_get_gpio_descs(struct spi_controller *ctlr)
3140 {
3141 int nb, i;
3142 struct gpio_desc **cs;
3143 struct device *dev = &ctlr->dev;
3144 unsigned long native_cs_mask = 0;
3145 unsigned int num_cs_gpios = 0;
3146
3147 nb = gpiod_count(dev, "cs");
3148 if (nb < 0) {
3149 /* No GPIOs at all is fine, else return the error */
3150 if (nb == -ENOENT)
3151 return 0;
3152 return nb;
3153 }
3154
3155 ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
3156
3157 cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
3158 GFP_KERNEL);
3159 if (!cs)
3160 return -ENOMEM;
3161 ctlr->cs_gpiods = cs;
3162
3163 for (i = 0; i < nb; i++) {
3164 /*
3165 * Most chipselects are active low, the inverted
3166 * semantics are handled by special quirks in gpiolib,
3167 * so initializing them GPIOD_OUT_LOW here means
3168 * "unasserted", in most cases this will drive the physical
3169 * line high.
3170 */
3171 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
3172 GPIOD_OUT_LOW);
3173 if (IS_ERR(cs[i]))
3174 return PTR_ERR(cs[i]);
3175
3176 if (cs[i]) {
3177 /*
3178 * If we find a CS GPIO, name it after the device and
3179 * chip select line.
3180 */
3181 char *gpioname;
3182
3183 gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
3184 dev_name(dev), i);
3185 if (!gpioname)
3186 return -ENOMEM;
3187 gpiod_set_consumer_name(cs[i], gpioname);
3188 num_cs_gpios++;
3189 continue;
3190 }
3191
3192 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
3193 dev_err(dev, "Invalid native chip select %d\n", i);
3194 return -EINVAL;
3195 }
3196 native_cs_mask |= BIT(i);
3197 }
3198
3199 ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
3200
3201 if ((ctlr->flags & SPI_CONTROLLER_GPIO_SS) && num_cs_gpios &&
3202 ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
3203 dev_err(dev, "No unused native chip select available\n");
3204 return -EINVAL;
3205 }
3206
3207 return 0;
3208 }
3209
spi_controller_check_ops(struct spi_controller * ctlr)3210 static int spi_controller_check_ops(struct spi_controller *ctlr)
3211 {
3212 /*
3213 * The controller may implement only the high-level SPI-memory like
3214 * operations if it does not support regular SPI transfers, and this is
3215 * valid use case.
3216 * If ->mem_ops or ->mem_ops->exec_op is NULL, we request that at least
3217 * one of the ->transfer_xxx() method be implemented.
3218 */
3219 if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
3220 if (!ctlr->transfer && !ctlr->transfer_one &&
3221 !ctlr->transfer_one_message) {
3222 return -EINVAL;
3223 }
3224 }
3225
3226 return 0;
3227 }
3228
3229 /* Allocate dynamic bus number using Linux idr */
spi_controller_id_alloc(struct spi_controller * ctlr,int start,int end)3230 static int spi_controller_id_alloc(struct spi_controller *ctlr, int start, int end)
3231 {
3232 int id;
3233
3234 mutex_lock(&board_lock);
3235 id = idr_alloc(&spi_master_idr, ctlr, start, end, GFP_KERNEL);
3236 mutex_unlock(&board_lock);
3237 if (WARN(id < 0, "couldn't get idr"))
3238 return id == -ENOSPC ? -EBUSY : id;
3239 ctlr->bus_num = id;
3240 return 0;
3241 }
3242
3243 /**
3244 * spi_register_controller - register SPI host or target controller
3245 * @ctlr: initialized controller, originally from spi_alloc_host() or
3246 * spi_alloc_target()
3247 * Context: can sleep
3248 *
3249 * SPI controllers connect to their drivers using some non-SPI bus,
3250 * such as the platform bus. The final stage of probe() in that code
3251 * includes calling spi_register_controller() to hook up to this SPI bus glue.
3252 *
3253 * SPI controllers use board specific (often SOC specific) bus numbers,
3254 * and board-specific addressing for SPI devices combines those numbers
3255 * with chip select numbers. Since SPI does not directly support dynamic
3256 * device identification, boards need configuration tables telling which
3257 * chip is at which address.
3258 *
3259 * This must be called from context that can sleep. It returns zero on
3260 * success, else a negative error code (dropping the controller's refcount).
3261 * After a successful return, the caller is responsible for calling
3262 * spi_unregister_controller().
3263 *
3264 * Return: zero on success, else a negative error code.
3265 */
spi_register_controller(struct spi_controller * ctlr)3266 int spi_register_controller(struct spi_controller *ctlr)
3267 {
3268 struct device *dev = ctlr->dev.parent;
3269 struct boardinfo *bi;
3270 int first_dynamic;
3271 int status;
3272 int idx;
3273
3274 if (!dev)
3275 return -ENODEV;
3276
3277 /*
3278 * Make sure all necessary hooks are implemented before registering
3279 * the SPI controller.
3280 */
3281 status = spi_controller_check_ops(ctlr);
3282 if (status)
3283 return status;
3284
3285 if (ctlr->bus_num < 0)
3286 ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi");
3287 if (ctlr->bus_num >= 0) {
3288 /* Devices with a fixed bus num must check-in with the num */
3289 status = spi_controller_id_alloc(ctlr, ctlr->bus_num, ctlr->bus_num + 1);
3290 if (status)
3291 return status;
3292 }
3293 if (ctlr->bus_num < 0) {
3294 first_dynamic = of_alias_get_highest_id("spi");
3295 if (first_dynamic < 0)
3296 first_dynamic = 0;
3297 else
3298 first_dynamic++;
3299
3300 status = spi_controller_id_alloc(ctlr, first_dynamic, 0);
3301 if (status)
3302 return status;
3303 }
3304 ctlr->bus_lock_flag = 0;
3305 init_completion(&ctlr->xfer_completion);
3306 init_completion(&ctlr->cur_msg_completion);
3307 if (!ctlr->max_dma_len)
3308 ctlr->max_dma_len = INT_MAX;
3309
3310 /*
3311 * Register the device, then userspace will see it.
3312 * Registration fails if the bus ID is in use.
3313 */
3314 dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3315
3316 if (!spi_controller_is_target(ctlr) && ctlr->use_gpio_descriptors) {
3317 status = spi_get_gpio_descs(ctlr);
3318 if (status)
3319 goto free_bus_id;
3320 /*
3321 * A controller using GPIO descriptors always
3322 * supports SPI_CS_HIGH if need be.
3323 */
3324 ctlr->mode_bits |= SPI_CS_HIGH;
3325 }
3326
3327 /*
3328 * Even if it's just one always-selected device, there must
3329 * be at least one chipselect.
3330 */
3331 if (!ctlr->num_chipselect) {
3332 status = -EINVAL;
3333 goto free_bus_id;
3334 }
3335
3336 /* Setting last_cs to SPI_INVALID_CS means no chip selected */
3337 for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
3338 ctlr->last_cs[idx] = SPI_INVALID_CS;
3339
3340 status = device_add(&ctlr->dev);
3341 if (status < 0)
3342 goto free_bus_id;
3343 dev_dbg(dev, "registered %s %s\n",
3344 spi_controller_is_target(ctlr) ? "target" : "host",
3345 dev_name(&ctlr->dev));
3346
3347 /*
3348 * If we're using a queued driver, start the queue. Note that we don't
3349 * need the queueing logic if the driver is only supporting high-level
3350 * memory operations.
3351 */
3352 if (ctlr->transfer) {
3353 dev_info(dev, "controller is unqueued, this is deprecated\n");
3354 } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3355 status = spi_controller_initialize_queue(ctlr);
3356 if (status) {
3357 device_del(&ctlr->dev);
3358 goto free_bus_id;
3359 }
3360 }
3361 /* Add statistics */
3362 ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3363 if (!ctlr->pcpu_statistics) {
3364 dev_err(dev, "Error allocating per-cpu statistics\n");
3365 status = -ENOMEM;
3366 goto destroy_queue;
3367 }
3368
3369 mutex_lock(&board_lock);
3370 list_add_tail(&ctlr->list, &spi_controller_list);
3371 list_for_each_entry(bi, &board_list, list)
3372 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3373 mutex_unlock(&board_lock);
3374
3375 /* Register devices from the device tree and ACPI */
3376 of_register_spi_devices(ctlr);
3377 acpi_register_spi_devices(ctlr);
3378 return status;
3379
3380 destroy_queue:
3381 spi_destroy_queue(ctlr);
3382 free_bus_id:
3383 mutex_lock(&board_lock);
3384 idr_remove(&spi_master_idr, ctlr->bus_num);
3385 mutex_unlock(&board_lock);
3386 return status;
3387 }
3388 EXPORT_SYMBOL_GPL(spi_register_controller);
3389
devm_spi_unregister(struct device * dev,void * res)3390 static void devm_spi_unregister(struct device *dev, void *res)
3391 {
3392 spi_unregister_controller(*(struct spi_controller **)res);
3393 }
3394
3395 /**
3396 * devm_spi_register_controller - register managed SPI host or target
3397 * controller
3398 * @dev: device managing SPI controller
3399 * @ctlr: initialized controller, originally from spi_alloc_host() or
3400 * spi_alloc_target()
3401 * Context: can sleep
3402 *
3403 * Register a SPI device as with spi_register_controller() which will
3404 * automatically be unregistered and freed.
3405 *
3406 * Return: zero on success, else a negative error code.
3407 */
devm_spi_register_controller(struct device * dev,struct spi_controller * ctlr)3408 int devm_spi_register_controller(struct device *dev,
3409 struct spi_controller *ctlr)
3410 {
3411 struct spi_controller **ptr;
3412 int ret;
3413
3414 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3415 if (!ptr)
3416 return -ENOMEM;
3417
3418 ret = spi_register_controller(ctlr);
3419 if (!ret) {
3420 *ptr = ctlr;
3421 devres_add(dev, ptr);
3422 } else {
3423 devres_free(ptr);
3424 }
3425
3426 return ret;
3427 }
3428 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3429
__unregister(struct device * dev,void * null)3430 static int __unregister(struct device *dev, void *null)
3431 {
3432 spi_unregister_device(to_spi_device(dev));
3433 return 0;
3434 }
3435
3436 /**
3437 * spi_unregister_controller - unregister SPI master or slave controller
3438 * @ctlr: the controller being unregistered
3439 * Context: can sleep
3440 *
3441 * This call is used only by SPI controller drivers, which are the
3442 * only ones directly touching chip registers.
3443 *
3444 * This must be called from context that can sleep.
3445 *
3446 * Note that this function also drops a reference to the controller.
3447 */
spi_unregister_controller(struct spi_controller * ctlr)3448 void spi_unregister_controller(struct spi_controller *ctlr)
3449 {
3450 struct spi_controller *found;
3451 int id = ctlr->bus_num;
3452
3453 /* Prevent addition of new devices, unregister existing ones */
3454 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3455 mutex_lock(&ctlr->add_lock);
3456
3457 device_for_each_child(&ctlr->dev, NULL, __unregister);
3458
3459 /* First make sure that this controller was ever added */
3460 mutex_lock(&board_lock);
3461 found = idr_find(&spi_master_idr, id);
3462 mutex_unlock(&board_lock);
3463 if (ctlr->queued) {
3464 if (spi_destroy_queue(ctlr))
3465 dev_err(&ctlr->dev, "queue remove failed\n");
3466 }
3467 mutex_lock(&board_lock);
3468 list_del(&ctlr->list);
3469 mutex_unlock(&board_lock);
3470
3471 device_del(&ctlr->dev);
3472
3473 /* Free bus id */
3474 mutex_lock(&board_lock);
3475 if (found == ctlr)
3476 idr_remove(&spi_master_idr, id);
3477 mutex_unlock(&board_lock);
3478
3479 if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3480 mutex_unlock(&ctlr->add_lock);
3481
3482 /*
3483 * Release the last reference on the controller if its driver
3484 * has not yet been converted to devm_spi_alloc_host/target().
3485 */
3486 if (!ctlr->devm_allocated)
3487 put_device(&ctlr->dev);
3488 }
3489 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3490
__spi_check_suspended(const struct spi_controller * ctlr)3491 static inline int __spi_check_suspended(const struct spi_controller *ctlr)
3492 {
3493 return ctlr->flags & SPI_CONTROLLER_SUSPENDED ? -ESHUTDOWN : 0;
3494 }
3495
__spi_mark_suspended(struct spi_controller * ctlr)3496 static inline void __spi_mark_suspended(struct spi_controller *ctlr)
3497 {
3498 mutex_lock(&ctlr->bus_lock_mutex);
3499 ctlr->flags |= SPI_CONTROLLER_SUSPENDED;
3500 mutex_unlock(&ctlr->bus_lock_mutex);
3501 }
3502
__spi_mark_resumed(struct spi_controller * ctlr)3503 static inline void __spi_mark_resumed(struct spi_controller *ctlr)
3504 {
3505 mutex_lock(&ctlr->bus_lock_mutex);
3506 ctlr->flags &= ~SPI_CONTROLLER_SUSPENDED;
3507 mutex_unlock(&ctlr->bus_lock_mutex);
3508 }
3509
spi_controller_suspend(struct spi_controller * ctlr)3510 int spi_controller_suspend(struct spi_controller *ctlr)
3511 {
3512 int ret = 0;
3513
3514 /* Basically no-ops for non-queued controllers */
3515 if (ctlr->queued) {
3516 ret = spi_stop_queue(ctlr);
3517 if (ret)
3518 dev_err(&ctlr->dev, "queue stop failed\n");
3519 }
3520
3521 __spi_mark_suspended(ctlr);
3522 return ret;
3523 }
3524 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3525
spi_controller_resume(struct spi_controller * ctlr)3526 int spi_controller_resume(struct spi_controller *ctlr)
3527 {
3528 int ret = 0;
3529
3530 __spi_mark_resumed(ctlr);
3531
3532 if (ctlr->queued) {
3533 ret = spi_start_queue(ctlr);
3534 if (ret)
3535 dev_err(&ctlr->dev, "queue restart failed\n");
3536 }
3537 return ret;
3538 }
3539 EXPORT_SYMBOL_GPL(spi_controller_resume);
3540
3541 /*-------------------------------------------------------------------------*/
3542
3543 /* Core methods for spi_message alterations */
3544
__spi_replace_transfers_release(struct spi_controller * ctlr,struct spi_message * msg,void * res)3545 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3546 struct spi_message *msg,
3547 void *res)
3548 {
3549 struct spi_replaced_transfers *rxfer = res;
3550 size_t i;
3551
3552 /* Call extra callback if requested */
3553 if (rxfer->release)
3554 rxfer->release(ctlr, msg, res);
3555
3556 /* Insert replaced transfers back into the message */
3557 list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3558
3559 /* Remove the formerly inserted entries */
3560 for (i = 0; i < rxfer->inserted; i++)
3561 list_del(&rxfer->inserted_transfers[i].transfer_list);
3562 }
3563
3564 /**
3565 * spi_replace_transfers - replace transfers with several transfers
3566 * and register change with spi_message.resources
3567 * @msg: the spi_message we work upon
3568 * @xfer_first: the first spi_transfer we want to replace
3569 * @remove: number of transfers to remove
3570 * @insert: the number of transfers we want to insert instead
3571 * @release: extra release code necessary in some circumstances
3572 * @extradatasize: extra data to allocate (with alignment guarantees
3573 * of struct @spi_transfer)
3574 * @gfp: gfp flags
3575 *
3576 * Returns: pointer to @spi_replaced_transfers,
3577 * PTR_ERR(...) in case of errors.
3578 */
spi_replace_transfers(struct spi_message * msg,struct spi_transfer * xfer_first,size_t remove,size_t insert,spi_replaced_release_t release,size_t extradatasize,gfp_t gfp)3579 static struct spi_replaced_transfers *spi_replace_transfers(
3580 struct spi_message *msg,
3581 struct spi_transfer *xfer_first,
3582 size_t remove,
3583 size_t insert,
3584 spi_replaced_release_t release,
3585 size_t extradatasize,
3586 gfp_t gfp)
3587 {
3588 struct spi_replaced_transfers *rxfer;
3589 struct spi_transfer *xfer;
3590 size_t i;
3591
3592 /* Allocate the structure using spi_res */
3593 rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3594 struct_size(rxfer, inserted_transfers, insert)
3595 + extradatasize,
3596 gfp);
3597 if (!rxfer)
3598 return ERR_PTR(-ENOMEM);
3599
3600 /* The release code to invoke before running the generic release */
3601 rxfer->release = release;
3602
3603 /* Assign extradata */
3604 if (extradatasize)
3605 rxfer->extradata =
3606 &rxfer->inserted_transfers[insert];
3607
3608 /* Init the replaced_transfers list */
3609 INIT_LIST_HEAD(&rxfer->replaced_transfers);
3610
3611 /*
3612 * Assign the list_entry after which we should reinsert
3613 * the @replaced_transfers - it may be spi_message.messages!
3614 */
3615 rxfer->replaced_after = xfer_first->transfer_list.prev;
3616
3617 /* Remove the requested number of transfers */
3618 for (i = 0; i < remove; i++) {
3619 /*
3620 * If the entry after replaced_after it is msg->transfers
3621 * then we have been requested to remove more transfers
3622 * than are in the list.
3623 */
3624 if (rxfer->replaced_after->next == &msg->transfers) {
3625 dev_err(&msg->spi->dev,
3626 "requested to remove more spi_transfers than are available\n");
3627 /* Insert replaced transfers back into the message */
3628 list_splice(&rxfer->replaced_transfers,
3629 rxfer->replaced_after);
3630
3631 /* Free the spi_replace_transfer structure... */
3632 spi_res_free(rxfer);
3633
3634 /* ...and return with an error */
3635 return ERR_PTR(-EINVAL);
3636 }
3637
3638 /*
3639 * Remove the entry after replaced_after from list of
3640 * transfers and add it to list of replaced_transfers.
3641 */
3642 list_move_tail(rxfer->replaced_after->next,
3643 &rxfer->replaced_transfers);
3644 }
3645
3646 /*
3647 * Create copy of the given xfer with identical settings
3648 * based on the first transfer to get removed.
3649 */
3650 for (i = 0; i < insert; i++) {
3651 /* We need to run in reverse order */
3652 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3653
3654 /* Copy all spi_transfer data */
3655 memcpy(xfer, xfer_first, sizeof(*xfer));
3656
3657 /* Add to list */
3658 list_add(&xfer->transfer_list, rxfer->replaced_after);
3659
3660 /* Clear cs_change and delay for all but the last */
3661 if (i) {
3662 xfer->cs_change = false;
3663 xfer->delay.value = 0;
3664 }
3665 }
3666
3667 /* Set up inserted... */
3668 rxfer->inserted = insert;
3669
3670 /* ...and register it with spi_res/spi_message */
3671 spi_res_add(msg, rxfer);
3672
3673 return rxfer;
3674 }
3675
__spi_split_transfer_maxsize(struct spi_controller * ctlr,struct spi_message * msg,struct spi_transfer ** xferp,size_t maxsize)3676 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3677 struct spi_message *msg,
3678 struct spi_transfer **xferp,
3679 size_t maxsize)
3680 {
3681 struct spi_transfer *xfer = *xferp, *xfers;
3682 struct spi_replaced_transfers *srt;
3683 size_t offset;
3684 size_t count, i;
3685
3686 /* Calculate how many we have to replace */
3687 count = DIV_ROUND_UP(xfer->len, maxsize);
3688
3689 /* Create replacement */
3690 srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, GFP_KERNEL);
3691 if (IS_ERR(srt))
3692 return PTR_ERR(srt);
3693 xfers = srt->inserted_transfers;
3694
3695 /*
3696 * Now handle each of those newly inserted spi_transfers.
3697 * Note that the replacements spi_transfers all are preset
3698 * to the same values as *xferp, so tx_buf, rx_buf and len
3699 * are all identical (as well as most others)
3700 * so we just have to fix up len and the pointers.
3701 */
3702
3703 /*
3704 * The first transfer just needs the length modified, so we
3705 * run it outside the loop.
3706 */
3707 xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3708
3709 /* All the others need rx_buf/tx_buf also set */
3710 for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3711 /* Update rx_buf, tx_buf and DMA */
3712 if (xfers[i].rx_buf)
3713 xfers[i].rx_buf += offset;
3714 if (xfers[i].tx_buf)
3715 xfers[i].tx_buf += offset;
3716
3717 /* Update length */
3718 xfers[i].len = min(maxsize, xfers[i].len - offset);
3719 }
3720
3721 /*
3722 * We set up xferp to the last entry we have inserted,
3723 * so that we skip those already split transfers.
3724 */
3725 *xferp = &xfers[count - 1];
3726
3727 /* Increment statistics counters */
3728 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3729 transfers_split_maxsize);
3730 SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3731 transfers_split_maxsize);
3732
3733 return 0;
3734 }
3735
3736 /**
3737 * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3738 * when an individual transfer exceeds a
3739 * certain size
3740 * @ctlr: the @spi_controller for this transfer
3741 * @msg: the @spi_message to transform
3742 * @maxsize: the maximum when to apply this
3743 *
3744 * This function allocates resources that are automatically freed during the
3745 * spi message unoptimize phase so this function should only be called from
3746 * optimize_message callbacks.
3747 *
3748 * Return: status of transformation
3749 */
spi_split_transfers_maxsize(struct spi_controller * ctlr,struct spi_message * msg,size_t maxsize)3750 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3751 struct spi_message *msg,
3752 size_t maxsize)
3753 {
3754 struct spi_transfer *xfer;
3755 int ret;
3756
3757 /*
3758 * Iterate over the transfer_list,
3759 * but note that xfer is advanced to the last transfer inserted
3760 * to avoid checking sizes again unnecessarily (also xfer does
3761 * potentially belong to a different list by the time the
3762 * replacement has happened).
3763 */
3764 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3765 if (xfer->len > maxsize) {
3766 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3767 maxsize);
3768 if (ret)
3769 return ret;
3770 }
3771 }
3772
3773 return 0;
3774 }
3775 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3776
3777
3778 /**
3779 * spi_split_transfers_maxwords - split SPI transfers into multiple transfers
3780 * when an individual transfer exceeds a
3781 * certain number of SPI words
3782 * @ctlr: the @spi_controller for this transfer
3783 * @msg: the @spi_message to transform
3784 * @maxwords: the number of words to limit each transfer to
3785 *
3786 * This function allocates resources that are automatically freed during the
3787 * spi message unoptimize phase so this function should only be called from
3788 * optimize_message callbacks.
3789 *
3790 * Return: status of transformation
3791 */
spi_split_transfers_maxwords(struct spi_controller * ctlr,struct spi_message * msg,size_t maxwords)3792 int spi_split_transfers_maxwords(struct spi_controller *ctlr,
3793 struct spi_message *msg,
3794 size_t maxwords)
3795 {
3796 struct spi_transfer *xfer;
3797
3798 /*
3799 * Iterate over the transfer_list,
3800 * but note that xfer is advanced to the last transfer inserted
3801 * to avoid checking sizes again unnecessarily (also xfer does
3802 * potentially belong to a different list by the time the
3803 * replacement has happened).
3804 */
3805 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3806 size_t maxsize;
3807 int ret;
3808
3809 maxsize = maxwords * roundup_pow_of_two(BITS_TO_BYTES(xfer->bits_per_word));
3810 if (xfer->len > maxsize) {
3811 ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3812 maxsize);
3813 if (ret)
3814 return ret;
3815 }
3816 }
3817
3818 return 0;
3819 }
3820 EXPORT_SYMBOL_GPL(spi_split_transfers_maxwords);
3821
3822 /*-------------------------------------------------------------------------*/
3823
3824 /*
3825 * Core methods for SPI controller protocol drivers. Some of the
3826 * other core methods are currently defined as inline functions.
3827 */
3828
__spi_validate_bits_per_word(struct spi_controller * ctlr,u8 bits_per_word)3829 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3830 u8 bits_per_word)
3831 {
3832 if (ctlr->bits_per_word_mask) {
3833 /* Only 32 bits fit in the mask */
3834 if (bits_per_word > 32)
3835 return -EINVAL;
3836 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3837 return -EINVAL;
3838 }
3839
3840 return 0;
3841 }
3842
3843 /**
3844 * spi_set_cs_timing - configure CS setup, hold, and inactive delays
3845 * @spi: the device that requires specific CS timing configuration
3846 *
3847 * Return: zero on success, else a negative error code.
3848 */
spi_set_cs_timing(struct spi_device * spi)3849 static int spi_set_cs_timing(struct spi_device *spi)
3850 {
3851 struct device *parent = spi->controller->dev.parent;
3852 int status = 0;
3853
3854 if (spi->controller->set_cs_timing && !spi_get_csgpiod(spi, 0)) {
3855 if (spi->controller->auto_runtime_pm) {
3856 status = pm_runtime_get_sync(parent);
3857 if (status < 0) {
3858 pm_runtime_put_noidle(parent);
3859 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3860 status);
3861 return status;
3862 }
3863
3864 status = spi->controller->set_cs_timing(spi);
3865 pm_runtime_mark_last_busy(parent);
3866 pm_runtime_put_autosuspend(parent);
3867 } else {
3868 status = spi->controller->set_cs_timing(spi);
3869 }
3870 }
3871 return status;
3872 }
3873
3874 /**
3875 * spi_setup - setup SPI mode and clock rate
3876 * @spi: the device whose settings are being modified
3877 * Context: can sleep, and no requests are queued to the device
3878 *
3879 * SPI protocol drivers may need to update the transfer mode if the
3880 * device doesn't work with its default. They may likewise need
3881 * to update clock rates or word sizes from initial values. This function
3882 * changes those settings, and must be called from a context that can sleep.
3883 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3884 * effect the next time the device is selected and data is transferred to
3885 * or from it. When this function returns, the SPI device is deselected.
3886 *
3887 * Note that this call will fail if the protocol driver specifies an option
3888 * that the underlying controller or its driver does not support. For
3889 * example, not all hardware supports wire transfers using nine bit words,
3890 * LSB-first wire encoding, or active-high chipselects.
3891 *
3892 * Return: zero on success, else a negative error code.
3893 */
spi_setup(struct spi_device * spi)3894 int spi_setup(struct spi_device *spi)
3895 {
3896 unsigned bad_bits, ugly_bits;
3897 int status;
3898
3899 /*
3900 * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3901 * are set at the same time.
3902 */
3903 if ((hweight_long(spi->mode &
3904 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3905 (hweight_long(spi->mode &
3906 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3907 dev_err(&spi->dev,
3908 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3909 return -EINVAL;
3910 }
3911 /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3912 if ((spi->mode & SPI_3WIRE) && (spi->mode &
3913 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3914 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3915 return -EINVAL;
3916 /* Check against conflicting MOSI idle configuration */
3917 if ((spi->mode & SPI_MOSI_IDLE_LOW) && (spi->mode & SPI_MOSI_IDLE_HIGH)) {
3918 dev_err(&spi->dev,
3919 "setup: MOSI configured to idle low and high at the same time.\n");
3920 return -EINVAL;
3921 }
3922 /*
3923 * Help drivers fail *cleanly* when they need options
3924 * that aren't supported with their current controller.
3925 * SPI_CS_WORD has a fallback software implementation,
3926 * so it is ignored here.
3927 */
3928 bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3929 SPI_NO_TX | SPI_NO_RX);
3930 ugly_bits = bad_bits &
3931 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3932 SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3933 if (ugly_bits) {
3934 dev_warn(&spi->dev,
3935 "setup: ignoring unsupported mode bits %x\n",
3936 ugly_bits);
3937 spi->mode &= ~ugly_bits;
3938 bad_bits &= ~ugly_bits;
3939 }
3940 if (bad_bits) {
3941 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3942 bad_bits);
3943 return -EINVAL;
3944 }
3945
3946 if (!spi->bits_per_word) {
3947 spi->bits_per_word = 8;
3948 } else {
3949 /*
3950 * Some controllers may not support the default 8 bits-per-word
3951 * so only perform the check when this is explicitly provided.
3952 */
3953 status = __spi_validate_bits_per_word(spi->controller,
3954 spi->bits_per_word);
3955 if (status)
3956 return status;
3957 }
3958
3959 if (spi->controller->max_speed_hz &&
3960 (!spi->max_speed_hz ||
3961 spi->max_speed_hz > spi->controller->max_speed_hz))
3962 spi->max_speed_hz = spi->controller->max_speed_hz;
3963
3964 mutex_lock(&spi->controller->io_mutex);
3965
3966 if (spi->controller->setup) {
3967 status = spi->controller->setup(spi);
3968 if (status) {
3969 mutex_unlock(&spi->controller->io_mutex);
3970 dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3971 status);
3972 return status;
3973 }
3974 }
3975
3976 status = spi_set_cs_timing(spi);
3977 if (status) {
3978 mutex_unlock(&spi->controller->io_mutex);
3979 return status;
3980 }
3981
3982 if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3983 status = pm_runtime_resume_and_get(spi->controller->dev.parent);
3984 if (status < 0) {
3985 mutex_unlock(&spi->controller->io_mutex);
3986 dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3987 status);
3988 return status;
3989 }
3990
3991 /*
3992 * We do not want to return positive value from pm_runtime_get,
3993 * there are many instances of devices calling spi_setup() and
3994 * checking for a non-zero return value instead of a negative
3995 * return value.
3996 */
3997 status = 0;
3998
3999 spi_set_cs(spi, false, true);
4000 pm_runtime_mark_last_busy(spi->controller->dev.parent);
4001 pm_runtime_put_autosuspend(spi->controller->dev.parent);
4002 } else {
4003 spi_set_cs(spi, false, true);
4004 }
4005
4006 mutex_unlock(&spi->controller->io_mutex);
4007
4008 if (spi->rt && !spi->controller->rt) {
4009 spi->controller->rt = true;
4010 spi_set_thread_rt(spi->controller);
4011 }
4012
4013 trace_spi_setup(spi, status);
4014
4015 dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
4016 spi->mode & SPI_MODE_X_MASK,
4017 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
4018 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
4019 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
4020 (spi->mode & SPI_LOOP) ? "loopback, " : "",
4021 spi->bits_per_word, spi->max_speed_hz,
4022 status);
4023
4024 return status;
4025 }
4026 EXPORT_SYMBOL_GPL(spi_setup);
4027
_spi_xfer_word_delay_update(struct spi_transfer * xfer,struct spi_device * spi)4028 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
4029 struct spi_device *spi)
4030 {
4031 int delay1, delay2;
4032
4033 delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
4034 if (delay1 < 0)
4035 return delay1;
4036
4037 delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
4038 if (delay2 < 0)
4039 return delay2;
4040
4041 if (delay1 < delay2)
4042 memcpy(&xfer->word_delay, &spi->word_delay,
4043 sizeof(xfer->word_delay));
4044
4045 return 0;
4046 }
4047
__spi_validate(struct spi_device * spi,struct spi_message * message)4048 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
4049 {
4050 struct spi_controller *ctlr = spi->controller;
4051 struct spi_transfer *xfer;
4052 int w_size;
4053
4054 if (list_empty(&message->transfers))
4055 return -EINVAL;
4056
4057 message->spi = spi;
4058
4059 /*
4060 * Half-duplex links include original MicroWire, and ones with
4061 * only one data pin like SPI_3WIRE (switches direction) or where
4062 * either MOSI or MISO is missing. They can also be caused by
4063 * software limitations.
4064 */
4065 if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
4066 (spi->mode & SPI_3WIRE)) {
4067 unsigned flags = ctlr->flags;
4068
4069 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4070 if (xfer->rx_buf && xfer->tx_buf)
4071 return -EINVAL;
4072 if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
4073 return -EINVAL;
4074 if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
4075 return -EINVAL;
4076 }
4077 }
4078
4079 /*
4080 * Set transfer bits_per_word and max speed as spi device default if
4081 * it is not set for this transfer.
4082 * Set transfer tx_nbits and rx_nbits as single transfer default
4083 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
4084 * Ensure transfer word_delay is at least as long as that required by
4085 * device itself.
4086 */
4087 message->frame_length = 0;
4088 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4089 xfer->effective_speed_hz = 0;
4090 message->frame_length += xfer->len;
4091 if (!xfer->bits_per_word)
4092 xfer->bits_per_word = spi->bits_per_word;
4093
4094 if (!xfer->speed_hz)
4095 xfer->speed_hz = spi->max_speed_hz;
4096
4097 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
4098 xfer->speed_hz = ctlr->max_speed_hz;
4099
4100 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
4101 return -EINVAL;
4102
4103 /*
4104 * SPI transfer length should be multiple of SPI word size
4105 * where SPI word size should be power-of-two multiple.
4106 */
4107 if (xfer->bits_per_word <= 8)
4108 w_size = 1;
4109 else if (xfer->bits_per_word <= 16)
4110 w_size = 2;
4111 else
4112 w_size = 4;
4113
4114 /* No partial transfers accepted */
4115 if (xfer->len % w_size)
4116 return -EINVAL;
4117
4118 if (xfer->speed_hz && ctlr->min_speed_hz &&
4119 xfer->speed_hz < ctlr->min_speed_hz)
4120 return -EINVAL;
4121
4122 if (xfer->tx_buf && !xfer->tx_nbits)
4123 xfer->tx_nbits = SPI_NBITS_SINGLE;
4124 if (xfer->rx_buf && !xfer->rx_nbits)
4125 xfer->rx_nbits = SPI_NBITS_SINGLE;
4126 /*
4127 * Check transfer tx/rx_nbits:
4128 * 1. check the value matches one of single, dual and quad
4129 * 2. check tx/rx_nbits match the mode in spi_device
4130 */
4131 if (xfer->tx_buf) {
4132 if (spi->mode & SPI_NO_TX)
4133 return -EINVAL;
4134 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
4135 xfer->tx_nbits != SPI_NBITS_DUAL &&
4136 xfer->tx_nbits != SPI_NBITS_QUAD &&
4137 xfer->tx_nbits != SPI_NBITS_OCTAL)
4138 return -EINVAL;
4139 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
4140 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
4141 return -EINVAL;
4142 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
4143 !(spi->mode & SPI_TX_QUAD))
4144 return -EINVAL;
4145 }
4146 /* Check transfer rx_nbits */
4147 if (xfer->rx_buf) {
4148 if (spi->mode & SPI_NO_RX)
4149 return -EINVAL;
4150 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
4151 xfer->rx_nbits != SPI_NBITS_DUAL &&
4152 xfer->rx_nbits != SPI_NBITS_QUAD &&
4153 xfer->rx_nbits != SPI_NBITS_OCTAL)
4154 return -EINVAL;
4155 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
4156 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
4157 return -EINVAL;
4158 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
4159 !(spi->mode & SPI_RX_QUAD))
4160 return -EINVAL;
4161 }
4162
4163 if (_spi_xfer_word_delay_update(xfer, spi))
4164 return -EINVAL;
4165 }
4166
4167 message->status = -EINPROGRESS;
4168
4169 return 0;
4170 }
4171
4172 /*
4173 * spi_split_transfers - generic handling of transfer splitting
4174 * @msg: the message to split
4175 *
4176 * Under certain conditions, a SPI controller may not support arbitrary
4177 * transfer sizes or other features required by a peripheral. This function
4178 * will split the transfers in the message into smaller transfers that are
4179 * supported by the controller.
4180 *
4181 * Controllers with special requirements not covered here can also split
4182 * transfers in the optimize_message() callback.
4183 *
4184 * Context: can sleep
4185 * Return: zero on success, else a negative error code
4186 */
spi_split_transfers(struct spi_message * msg)4187 static int spi_split_transfers(struct spi_message *msg)
4188 {
4189 struct spi_controller *ctlr = msg->spi->controller;
4190 struct spi_transfer *xfer;
4191 int ret;
4192
4193 /*
4194 * If an SPI controller does not support toggling the CS line on each
4195 * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
4196 * for the CS line, we can emulate the CS-per-word hardware function by
4197 * splitting transfers into one-word transfers and ensuring that
4198 * cs_change is set for each transfer.
4199 */
4200 if ((msg->spi->mode & SPI_CS_WORD) &&
4201 (!(ctlr->mode_bits & SPI_CS_WORD) || spi_is_csgpiod(msg->spi))) {
4202 ret = spi_split_transfers_maxwords(ctlr, msg, 1);
4203 if (ret)
4204 return ret;
4205
4206 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
4207 /* Don't change cs_change on the last entry in the list */
4208 if (list_is_last(&xfer->transfer_list, &msg->transfers))
4209 break;
4210
4211 xfer->cs_change = 1;
4212 }
4213 } else {
4214 ret = spi_split_transfers_maxsize(ctlr, msg,
4215 spi_max_transfer_size(msg->spi));
4216 if (ret)
4217 return ret;
4218 }
4219
4220 return 0;
4221 }
4222
4223 /*
4224 * __spi_optimize_message - shared implementation for spi_optimize_message()
4225 * and spi_maybe_optimize_message()
4226 * @spi: the device that will be used for the message
4227 * @msg: the message to optimize
4228 *
4229 * Peripheral drivers will call spi_optimize_message() and the spi core will
4230 * call spi_maybe_optimize_message() instead of calling this directly.
4231 *
4232 * It is not valid to call this on a message that has already been optimized.
4233 *
4234 * Return: zero on success, else a negative error code
4235 */
__spi_optimize_message(struct spi_device * spi,struct spi_message * msg)4236 static int __spi_optimize_message(struct spi_device *spi,
4237 struct spi_message *msg)
4238 {
4239 struct spi_controller *ctlr = spi->controller;
4240 int ret;
4241
4242 ret = __spi_validate(spi, msg);
4243 if (ret)
4244 return ret;
4245
4246 ret = spi_split_transfers(msg);
4247 if (ret)
4248 return ret;
4249
4250 if (ctlr->optimize_message) {
4251 ret = ctlr->optimize_message(msg);
4252 if (ret) {
4253 spi_res_release(ctlr, msg);
4254 return ret;
4255 }
4256 }
4257
4258 msg->optimized = true;
4259
4260 return 0;
4261 }
4262
4263 /*
4264 * spi_maybe_optimize_message - optimize message if it isn't already pre-optimized
4265 * @spi: the device that will be used for the message
4266 * @msg: the message to optimize
4267 * Return: zero on success, else a negative error code
4268 */
spi_maybe_optimize_message(struct spi_device * spi,struct spi_message * msg)4269 static int spi_maybe_optimize_message(struct spi_device *spi,
4270 struct spi_message *msg)
4271 {
4272 if (spi->controller->defer_optimize_message) {
4273 msg->spi = spi;
4274 return 0;
4275 }
4276
4277 if (msg->pre_optimized)
4278 return 0;
4279
4280 return __spi_optimize_message(spi, msg);
4281 }
4282
4283 /**
4284 * spi_optimize_message - do any one-time validation and setup for a SPI message
4285 * @spi: the device that will be used for the message
4286 * @msg: the message to optimize
4287 *
4288 * Peripheral drivers that reuse the same message repeatedly may call this to
4289 * perform as much message prep as possible once, rather than repeating it each
4290 * time a message transfer is performed to improve throughput and reduce CPU
4291 * usage.
4292 *
4293 * Once a message has been optimized, it cannot be modified with the exception
4294 * of updating the contents of any xfer->tx_buf (the pointer can't be changed,
4295 * only the data in the memory it points to).
4296 *
4297 * Calls to this function must be balanced with calls to spi_unoptimize_message()
4298 * to avoid leaking resources.
4299 *
4300 * Context: can sleep
4301 * Return: zero on success, else a negative error code
4302 */
spi_optimize_message(struct spi_device * spi,struct spi_message * msg)4303 int spi_optimize_message(struct spi_device *spi, struct spi_message *msg)
4304 {
4305 int ret;
4306
4307 /*
4308 * Pre-optimization is not supported and optimization is deferred e.g.
4309 * when using spi-mux.
4310 */
4311 if (spi->controller->defer_optimize_message)
4312 return 0;
4313
4314 ret = __spi_optimize_message(spi, msg);
4315 if (ret)
4316 return ret;
4317
4318 /*
4319 * This flag indicates that the peripheral driver called spi_optimize_message()
4320 * and therefore we shouldn't unoptimize message automatically when finalizing
4321 * the message but rather wait until spi_unoptimize_message() is called
4322 * by the peripheral driver.
4323 */
4324 msg->pre_optimized = true;
4325
4326 return 0;
4327 }
4328 EXPORT_SYMBOL_GPL(spi_optimize_message);
4329
4330 /**
4331 * spi_unoptimize_message - releases any resources allocated by spi_optimize_message()
4332 * @msg: the message to unoptimize
4333 *
4334 * Calls to this function must be balanced with calls to spi_optimize_message().
4335 *
4336 * Context: can sleep
4337 */
spi_unoptimize_message(struct spi_message * msg)4338 void spi_unoptimize_message(struct spi_message *msg)
4339 {
4340 if (msg->spi->controller->defer_optimize_message)
4341 return;
4342
4343 __spi_unoptimize_message(msg);
4344 msg->pre_optimized = false;
4345 }
4346 EXPORT_SYMBOL_GPL(spi_unoptimize_message);
4347
__spi_async(struct spi_device * spi,struct spi_message * message)4348 static int __spi_async(struct spi_device *spi, struct spi_message *message)
4349 {
4350 struct spi_controller *ctlr = spi->controller;
4351 struct spi_transfer *xfer;
4352
4353 /*
4354 * Some controllers do not support doing regular SPI transfers. Return
4355 * ENOTSUPP when this is the case.
4356 */
4357 if (!ctlr->transfer)
4358 return -ENOTSUPP;
4359
4360 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
4361 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
4362
4363 trace_spi_message_submit(message);
4364
4365 if (!ctlr->ptp_sts_supported) {
4366 list_for_each_entry(xfer, &message->transfers, transfer_list) {
4367 xfer->ptp_sts_word_pre = 0;
4368 ptp_read_system_prets(xfer->ptp_sts);
4369 }
4370 }
4371
4372 return ctlr->transfer(spi, message);
4373 }
4374
devm_spi_unoptimize_message(void * msg)4375 static void devm_spi_unoptimize_message(void *msg)
4376 {
4377 spi_unoptimize_message(msg);
4378 }
4379
4380 /**
4381 * devm_spi_optimize_message - managed version of spi_optimize_message()
4382 * @dev: the device that manages @msg (usually @spi->dev)
4383 * @spi: the device that will be used for the message
4384 * @msg: the message to optimize
4385 * Return: zero on success, else a negative error code
4386 *
4387 * spi_unoptimize_message() will automatically be called when the device is
4388 * removed.
4389 */
devm_spi_optimize_message(struct device * dev,struct spi_device * spi,struct spi_message * msg)4390 int devm_spi_optimize_message(struct device *dev, struct spi_device *spi,
4391 struct spi_message *msg)
4392 {
4393 int ret;
4394
4395 ret = spi_optimize_message(spi, msg);
4396 if (ret)
4397 return ret;
4398
4399 return devm_add_action_or_reset(dev, devm_spi_unoptimize_message, msg);
4400 }
4401 EXPORT_SYMBOL_GPL(devm_spi_optimize_message);
4402
4403 /**
4404 * spi_async - asynchronous SPI transfer
4405 * @spi: device with which data will be exchanged
4406 * @message: describes the data transfers, including completion callback
4407 * Context: any (IRQs may be blocked, etc)
4408 *
4409 * This call may be used in_irq and other contexts which can't sleep,
4410 * as well as from task contexts which can sleep.
4411 *
4412 * The completion callback is invoked in a context which can't sleep.
4413 * Before that invocation, the value of message->status is undefined.
4414 * When the callback is issued, message->status holds either zero (to
4415 * indicate complete success) or a negative error code. After that
4416 * callback returns, the driver which issued the transfer request may
4417 * deallocate the associated memory; it's no longer in use by any SPI
4418 * core or controller driver code.
4419 *
4420 * Note that although all messages to a spi_device are handled in
4421 * FIFO order, messages may go to different devices in other orders.
4422 * Some device might be higher priority, or have various "hard" access
4423 * time requirements, for example.
4424 *
4425 * On detection of any fault during the transfer, processing of
4426 * the entire message is aborted, and the device is deselected.
4427 * Until returning from the associated message completion callback,
4428 * no other spi_message queued to that device will be processed.
4429 * (This rule applies equally to all the synchronous transfer calls,
4430 * which are wrappers around this core asynchronous primitive.)
4431 *
4432 * Return: zero on success, else a negative error code.
4433 */
spi_async(struct spi_device * spi,struct spi_message * message)4434 int spi_async(struct spi_device *spi, struct spi_message *message)
4435 {
4436 struct spi_controller *ctlr = spi->controller;
4437 int ret;
4438 unsigned long flags;
4439
4440 ret = spi_maybe_optimize_message(spi, message);
4441 if (ret)
4442 return ret;
4443
4444 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4445
4446 if (ctlr->bus_lock_flag)
4447 ret = -EBUSY;
4448 else
4449 ret = __spi_async(spi, message);
4450
4451 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4452
4453 return ret;
4454 }
4455 EXPORT_SYMBOL_GPL(spi_async);
4456
__spi_transfer_message_noqueue(struct spi_controller * ctlr,struct spi_message * msg)4457 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
4458 {
4459 bool was_busy;
4460 int ret;
4461
4462 mutex_lock(&ctlr->io_mutex);
4463
4464 was_busy = ctlr->busy;
4465
4466 ctlr->cur_msg = msg;
4467 ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
4468 if (ret)
4469 dev_err(&ctlr->dev, "noqueue transfer failed\n");
4470 ctlr->cur_msg = NULL;
4471 ctlr->fallback = false;
4472
4473 if (!was_busy) {
4474 kfree(ctlr->dummy_rx);
4475 ctlr->dummy_rx = NULL;
4476 kfree(ctlr->dummy_tx);
4477 ctlr->dummy_tx = NULL;
4478 if (ctlr->unprepare_transfer_hardware &&
4479 ctlr->unprepare_transfer_hardware(ctlr))
4480 dev_err(&ctlr->dev,
4481 "failed to unprepare transfer hardware\n");
4482 spi_idle_runtime_pm(ctlr);
4483 }
4484
4485 mutex_unlock(&ctlr->io_mutex);
4486 }
4487
4488 /*-------------------------------------------------------------------------*/
4489
4490 /*
4491 * Utility methods for SPI protocol drivers, layered on
4492 * top of the core. Some other utility methods are defined as
4493 * inline functions.
4494 */
4495
spi_complete(void * arg)4496 static void spi_complete(void *arg)
4497 {
4498 complete(arg);
4499 }
4500
__spi_sync(struct spi_device * spi,struct spi_message * message)4501 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4502 {
4503 DECLARE_COMPLETION_ONSTACK(done);
4504 unsigned long flags;
4505 int status;
4506 struct spi_controller *ctlr = spi->controller;
4507
4508 if (__spi_check_suspended(ctlr)) {
4509 dev_warn_once(&spi->dev, "Attempted to sync while suspend\n");
4510 return -ESHUTDOWN;
4511 }
4512
4513 status = spi_maybe_optimize_message(spi, message);
4514 if (status)
4515 return status;
4516
4517 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4518 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4519
4520 /*
4521 * Checking queue_empty here only guarantees async/sync message
4522 * ordering when coming from the same context. It does not need to
4523 * guard against reentrancy from a different context. The io_mutex
4524 * will catch those cases.
4525 */
4526 if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
4527 message->actual_length = 0;
4528 message->status = -EINPROGRESS;
4529
4530 trace_spi_message_submit(message);
4531
4532 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4533 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4534
4535 __spi_transfer_message_noqueue(ctlr, message);
4536
4537 return message->status;
4538 }
4539
4540 /*
4541 * There are messages in the async queue that could have originated
4542 * from the same context, so we need to preserve ordering.
4543 * Therefor we send the message to the async queue and wait until they
4544 * are completed.
4545 */
4546 message->complete = spi_complete;
4547 message->context = &done;
4548
4549 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4550 status = __spi_async(spi, message);
4551 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4552
4553 if (status == 0) {
4554 wait_for_completion(&done);
4555 status = message->status;
4556 }
4557 message->complete = NULL;
4558 message->context = NULL;
4559
4560 return status;
4561 }
4562
4563 /**
4564 * spi_sync - blocking/synchronous SPI data transfers
4565 * @spi: device with which data will be exchanged
4566 * @message: describes the data transfers
4567 * Context: can sleep
4568 *
4569 * This call may only be used from a context that may sleep. The sleep
4570 * is non-interruptible, and has no timeout. Low-overhead controller
4571 * drivers may DMA directly into and out of the message buffers.
4572 *
4573 * Note that the SPI device's chip select is active during the message,
4574 * and then is normally disabled between messages. Drivers for some
4575 * frequently-used devices may want to minimize costs of selecting a chip,
4576 * by leaving it selected in anticipation that the next message will go
4577 * to the same chip. (That may increase power usage.)
4578 *
4579 * Also, the caller is guaranteeing that the memory associated with the
4580 * message will not be freed before this call returns.
4581 *
4582 * Return: zero on success, else a negative error code.
4583 */
spi_sync(struct spi_device * spi,struct spi_message * message)4584 int spi_sync(struct spi_device *spi, struct spi_message *message)
4585 {
4586 int ret;
4587
4588 mutex_lock(&spi->controller->bus_lock_mutex);
4589 ret = __spi_sync(spi, message);
4590 mutex_unlock(&spi->controller->bus_lock_mutex);
4591
4592 return ret;
4593 }
4594 EXPORT_SYMBOL_GPL(spi_sync);
4595
4596 /**
4597 * spi_sync_locked - version of spi_sync with exclusive bus usage
4598 * @spi: device with which data will be exchanged
4599 * @message: describes the data transfers
4600 * Context: can sleep
4601 *
4602 * This call may only be used from a context that may sleep. The sleep
4603 * is non-interruptible, and has no timeout. Low-overhead controller
4604 * drivers may DMA directly into and out of the message buffers.
4605 *
4606 * This call should be used by drivers that require exclusive access to the
4607 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4608 * be released by a spi_bus_unlock call when the exclusive access is over.
4609 *
4610 * Return: zero on success, else a negative error code.
4611 */
spi_sync_locked(struct spi_device * spi,struct spi_message * message)4612 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4613 {
4614 return __spi_sync(spi, message);
4615 }
4616 EXPORT_SYMBOL_GPL(spi_sync_locked);
4617
4618 /**
4619 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4620 * @ctlr: SPI bus master that should be locked for exclusive bus access
4621 * Context: can sleep
4622 *
4623 * This call may only be used from a context that may sleep. The sleep
4624 * is non-interruptible, and has no timeout.
4625 *
4626 * This call should be used by drivers that require exclusive access to the
4627 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4628 * exclusive access is over. Data transfer must be done by spi_sync_locked
4629 * and spi_async_locked calls when the SPI bus lock is held.
4630 *
4631 * Return: always zero.
4632 */
spi_bus_lock(struct spi_controller * ctlr)4633 int spi_bus_lock(struct spi_controller *ctlr)
4634 {
4635 unsigned long flags;
4636
4637 mutex_lock(&ctlr->bus_lock_mutex);
4638
4639 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4640 ctlr->bus_lock_flag = 1;
4641 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4642
4643 /* Mutex remains locked until spi_bus_unlock() is called */
4644
4645 return 0;
4646 }
4647 EXPORT_SYMBOL_GPL(spi_bus_lock);
4648
4649 /**
4650 * spi_bus_unlock - release the lock for exclusive SPI bus usage
4651 * @ctlr: SPI bus master that was locked for exclusive bus access
4652 * Context: can sleep
4653 *
4654 * This call may only be used from a context that may sleep. The sleep
4655 * is non-interruptible, and has no timeout.
4656 *
4657 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4658 * call.
4659 *
4660 * Return: always zero.
4661 */
spi_bus_unlock(struct spi_controller * ctlr)4662 int spi_bus_unlock(struct spi_controller *ctlr)
4663 {
4664 ctlr->bus_lock_flag = 0;
4665
4666 mutex_unlock(&ctlr->bus_lock_mutex);
4667
4668 return 0;
4669 }
4670 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4671
4672 /* Portable code must never pass more than 32 bytes */
4673 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
4674
4675 static u8 *buf;
4676
4677 /**
4678 * spi_write_then_read - SPI synchronous write followed by read
4679 * @spi: device with which data will be exchanged
4680 * @txbuf: data to be written (need not be DMA-safe)
4681 * @n_tx: size of txbuf, in bytes
4682 * @rxbuf: buffer into which data will be read (need not be DMA-safe)
4683 * @n_rx: size of rxbuf, in bytes
4684 * Context: can sleep
4685 *
4686 * This performs a half duplex MicroWire style transaction with the
4687 * device, sending txbuf and then reading rxbuf. The return value
4688 * is zero for success, else a negative errno status code.
4689 * This call may only be used from a context that may sleep.
4690 *
4691 * Parameters to this routine are always copied using a small buffer.
4692 * Performance-sensitive or bulk transfer code should instead use
4693 * spi_{async,sync}() calls with DMA-safe buffers.
4694 *
4695 * Return: zero on success, else a negative error code.
4696 */
spi_write_then_read(struct spi_device * spi,const void * txbuf,unsigned n_tx,void * rxbuf,unsigned n_rx)4697 int spi_write_then_read(struct spi_device *spi,
4698 const void *txbuf, unsigned n_tx,
4699 void *rxbuf, unsigned n_rx)
4700 {
4701 static DEFINE_MUTEX(lock);
4702
4703 int status;
4704 struct spi_message message;
4705 struct spi_transfer x[2];
4706 u8 *local_buf;
4707
4708 /*
4709 * Use preallocated DMA-safe buffer if we can. We can't avoid
4710 * copying here, (as a pure convenience thing), but we can
4711 * keep heap costs out of the hot path unless someone else is
4712 * using the pre-allocated buffer or the transfer is too large.
4713 */
4714 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4715 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4716 GFP_KERNEL | GFP_DMA);
4717 if (!local_buf)
4718 return -ENOMEM;
4719 } else {
4720 local_buf = buf;
4721 }
4722
4723 spi_message_init(&message);
4724 memset(x, 0, sizeof(x));
4725 if (n_tx) {
4726 x[0].len = n_tx;
4727 spi_message_add_tail(&x[0], &message);
4728 }
4729 if (n_rx) {
4730 x[1].len = n_rx;
4731 spi_message_add_tail(&x[1], &message);
4732 }
4733
4734 memcpy(local_buf, txbuf, n_tx);
4735 x[0].tx_buf = local_buf;
4736 x[1].rx_buf = local_buf + n_tx;
4737
4738 /* Do the I/O */
4739 status = spi_sync(spi, &message);
4740 if (status == 0)
4741 memcpy(rxbuf, x[1].rx_buf, n_rx);
4742
4743 if (x[0].tx_buf == buf)
4744 mutex_unlock(&lock);
4745 else
4746 kfree(local_buf);
4747
4748 return status;
4749 }
4750 EXPORT_SYMBOL_GPL(spi_write_then_read);
4751
4752 /*-------------------------------------------------------------------------*/
4753
4754 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4755 /* Must call put_device() when done with returned spi_device device */
of_find_spi_device_by_node(struct device_node * node)4756 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4757 {
4758 struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4759
4760 return dev ? to_spi_device(dev) : NULL;
4761 }
4762
4763 /* The spi controllers are not using spi_bus, so we find it with another way */
of_find_spi_controller_by_node(struct device_node * node)4764 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4765 {
4766 struct device *dev;
4767
4768 dev = class_find_device_by_of_node(&spi_master_class, node);
4769 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4770 dev = class_find_device_by_of_node(&spi_slave_class, node);
4771 if (!dev)
4772 return NULL;
4773
4774 /* Reference got in class_find_device */
4775 return container_of(dev, struct spi_controller, dev);
4776 }
4777
of_spi_notify(struct notifier_block * nb,unsigned long action,void * arg)4778 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4779 void *arg)
4780 {
4781 struct of_reconfig_data *rd = arg;
4782 struct spi_controller *ctlr;
4783 struct spi_device *spi;
4784
4785 switch (of_reconfig_get_state_change(action, arg)) {
4786 case OF_RECONFIG_CHANGE_ADD:
4787 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4788 if (ctlr == NULL)
4789 return NOTIFY_OK; /* Not for us */
4790
4791 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4792 put_device(&ctlr->dev);
4793 return NOTIFY_OK;
4794 }
4795
4796 /*
4797 * Clear the flag before adding the device so that fw_devlink
4798 * doesn't skip adding consumers to this device.
4799 */
4800 rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
4801 spi = of_register_spi_device(ctlr, rd->dn);
4802 put_device(&ctlr->dev);
4803
4804 if (IS_ERR(spi)) {
4805 pr_err("%s: failed to create for '%pOF'\n",
4806 __func__, rd->dn);
4807 of_node_clear_flag(rd->dn, OF_POPULATED);
4808 return notifier_from_errno(PTR_ERR(spi));
4809 }
4810 break;
4811
4812 case OF_RECONFIG_CHANGE_REMOVE:
4813 /* Already depopulated? */
4814 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4815 return NOTIFY_OK;
4816
4817 /* Find our device by node */
4818 spi = of_find_spi_device_by_node(rd->dn);
4819 if (spi == NULL)
4820 return NOTIFY_OK; /* No? not meant for us */
4821
4822 /* Unregister takes one ref away */
4823 spi_unregister_device(spi);
4824
4825 /* And put the reference of the find */
4826 put_device(&spi->dev);
4827 break;
4828 }
4829
4830 return NOTIFY_OK;
4831 }
4832
4833 static struct notifier_block spi_of_notifier = {
4834 .notifier_call = of_spi_notify,
4835 };
4836 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4837 extern struct notifier_block spi_of_notifier;
4838 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4839
4840 #if IS_ENABLED(CONFIG_ACPI)
spi_acpi_controller_match(struct device * dev,const void * data)4841 static int spi_acpi_controller_match(struct device *dev, const void *data)
4842 {
4843 return device_match_acpi_dev(dev->parent, data);
4844 }
4845
acpi_spi_find_controller_by_adev(struct acpi_device * adev)4846 struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4847 {
4848 struct device *dev;
4849
4850 dev = class_find_device(&spi_master_class, NULL, adev,
4851 spi_acpi_controller_match);
4852 if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4853 dev = class_find_device(&spi_slave_class, NULL, adev,
4854 spi_acpi_controller_match);
4855 if (!dev)
4856 return NULL;
4857
4858 return container_of(dev, struct spi_controller, dev);
4859 }
4860 EXPORT_SYMBOL_GPL(acpi_spi_find_controller_by_adev);
4861
acpi_spi_find_device_by_adev(struct acpi_device * adev)4862 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4863 {
4864 struct device *dev;
4865
4866 dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4867 return to_spi_device(dev);
4868 }
4869
acpi_spi_notify(struct notifier_block * nb,unsigned long value,void * arg)4870 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4871 void *arg)
4872 {
4873 struct acpi_device *adev = arg;
4874 struct spi_controller *ctlr;
4875 struct spi_device *spi;
4876
4877 switch (value) {
4878 case ACPI_RECONFIG_DEVICE_ADD:
4879 ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
4880 if (!ctlr)
4881 break;
4882
4883 acpi_register_spi_device(ctlr, adev);
4884 put_device(&ctlr->dev);
4885 break;
4886 case ACPI_RECONFIG_DEVICE_REMOVE:
4887 if (!acpi_device_enumerated(adev))
4888 break;
4889
4890 spi = acpi_spi_find_device_by_adev(adev);
4891 if (!spi)
4892 break;
4893
4894 spi_unregister_device(spi);
4895 put_device(&spi->dev);
4896 break;
4897 }
4898
4899 return NOTIFY_OK;
4900 }
4901
4902 static struct notifier_block spi_acpi_notifier = {
4903 .notifier_call = acpi_spi_notify,
4904 };
4905 #else
4906 extern struct notifier_block spi_acpi_notifier;
4907 #endif
4908
spi_init(void)4909 static int __init spi_init(void)
4910 {
4911 int status;
4912
4913 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4914 if (!buf) {
4915 status = -ENOMEM;
4916 goto err0;
4917 }
4918
4919 status = bus_register(&spi_bus_type);
4920 if (status < 0)
4921 goto err1;
4922
4923 status = class_register(&spi_master_class);
4924 if (status < 0)
4925 goto err2;
4926
4927 if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4928 status = class_register(&spi_slave_class);
4929 if (status < 0)
4930 goto err3;
4931 }
4932
4933 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4934 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4935 if (IS_ENABLED(CONFIG_ACPI))
4936 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4937
4938 return 0;
4939
4940 err3:
4941 class_unregister(&spi_master_class);
4942 err2:
4943 bus_unregister(&spi_bus_type);
4944 err1:
4945 kfree(buf);
4946 buf = NULL;
4947 err0:
4948 return status;
4949 }
4950
4951 /*
4952 * A board_info is normally registered in arch_initcall(),
4953 * but even essential drivers wait till later.
4954 *
4955 * REVISIT only boardinfo really needs static linking. The rest (device and
4956 * driver registration) _could_ be dynamically linked (modular) ... Costs
4957 * include needing to have boardinfo data structures be much more public.
4958 */
4959 postcore_initcall(spi_init);
4960