1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/anon_inodes.h>
4 #include <linux/atomic.h>
5 #include <linux/bitmap.h>
6 #include <linux/build_bug.h>
7 #include <linux/cdev.h>
8 #include <linux/cleanup.h>
9 #include <linux/compat.h>
10 #include <linux/compiler.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/file.h>
14 #include <linux/gpio.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/hte.h>
17 #include <linux/interrupt.h>
18 #include <linux/irqreturn.h>
19 #include <linux/kfifo.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/overflow.h>
23 #include <linux/pinctrl/consumer.h>
24 #include <linux/poll.h>
25 #include <linux/seq_file.h>
26 #include <linux/spinlock.h>
27 #include <linux/string.h>
28 #include <linux/timekeeping.h>
29 #include <linux/uaccess.h>
30 #include <linux/workqueue.h>
31
32 #include <uapi/linux/gpio.h>
33
34 #include "gpiolib.h"
35 #include "gpiolib-cdev.h"
36
37 /*
38 * Array sizes must ensure 64-bit alignment and not create holes in the
39 * struct packing.
40 */
41 static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
42 static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));
43
44 /*
45 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
46 */
47 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
48 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
49 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
50 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
51 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
52 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
53 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
54 static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));
55
56 /* Character device interface to GPIO.
57 *
58 * The GPIO character device, /dev/gpiochipN, provides userspace an
59 * interface to gpiolib GPIOs via ioctl()s.
60 */
61
62 /*
63 * GPIO line handle management
64 */
65
66 #ifdef CONFIG_GPIO_CDEV_V1
67 /**
68 * struct linehandle_state - contains the state of a userspace handle
69 * @gdev: the GPIO device the handle pertains to
70 * @label: consumer label used to tag descriptors
71 * @descs: the GPIO descriptors held by this handle
72 * @num_descs: the number of descriptors held in the descs array
73 */
74 struct linehandle_state {
75 struct gpio_device *gdev;
76 const char *label;
77 struct gpio_desc *descs[GPIOHANDLES_MAX];
78 u32 num_descs;
79 };
80
81 #define GPIOHANDLE_REQUEST_VALID_FLAGS \
82 (GPIOHANDLE_REQUEST_INPUT | \
83 GPIOHANDLE_REQUEST_OUTPUT | \
84 GPIOHANDLE_REQUEST_ACTIVE_LOW | \
85 GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
86 GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
87 GPIOHANDLE_REQUEST_BIAS_DISABLE | \
88 GPIOHANDLE_REQUEST_OPEN_DRAIN | \
89 GPIOHANDLE_REQUEST_OPEN_SOURCE)
90
91 #define GPIOHANDLE_REQUEST_DIRECTION_FLAGS \
92 (GPIOHANDLE_REQUEST_INPUT | \
93 GPIOHANDLE_REQUEST_OUTPUT)
94
linehandle_validate_flags(u32 flags)95 static int linehandle_validate_flags(u32 flags)
96 {
97 /* Return an error if an unknown flag is set */
98 if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
99 return -EINVAL;
100
101 /*
102 * Do not allow both INPUT & OUTPUT flags to be set as they are
103 * contradictory.
104 */
105 if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
106 (flags & GPIOHANDLE_REQUEST_OUTPUT))
107 return -EINVAL;
108
109 /*
110 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
111 * the hardware actually supports enabling both at the same time the
112 * electrical result would be disastrous.
113 */
114 if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
115 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
116 return -EINVAL;
117
118 /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
119 if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
120 ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
121 (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
122 return -EINVAL;
123
124 /* Bias flags only allowed for input or output mode. */
125 if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
126 (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
127 ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
128 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
129 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
130 return -EINVAL;
131
132 /* Only one bias flag can be set. */
133 if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
134 (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
135 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
136 ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
137 (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
138 return -EINVAL;
139
140 return 0;
141 }
142
linehandle_flags_to_desc_flags(u32 lflags,unsigned long * flagsp)143 static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
144 {
145 unsigned long flags = READ_ONCE(*flagsp);
146
147 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags,
148 lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
149 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags,
150 lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
151 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags,
152 lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
153 assign_bit(GPIOD_FLAG_PULL_UP, &flags,
154 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
155 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags,
156 lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
157 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags,
158 lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
159
160 WRITE_ONCE(*flagsp, flags);
161 }
162
linehandle_set_config(struct linehandle_state * lh,void __user * ip)163 static long linehandle_set_config(struct linehandle_state *lh,
164 void __user *ip)
165 {
166 struct gpiohandle_config gcnf;
167 struct gpio_desc *desc;
168 int i, ret;
169 u32 lflags;
170
171 if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
172 return -EFAULT;
173
174 lflags = gcnf.flags;
175 ret = linehandle_validate_flags(lflags);
176 if (ret)
177 return ret;
178
179 /* Lines must be reconfigured explicitly as input or output. */
180 if (!(lflags & GPIOHANDLE_REQUEST_DIRECTION_FLAGS))
181 return -EINVAL;
182
183 for (i = 0; i < lh->num_descs; i++) {
184 desc = lh->descs[i];
185 linehandle_flags_to_desc_flags(lflags, &desc->flags);
186
187 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
188 int val = !!gcnf.default_values[i];
189
190 ret = gpiod_direction_output_nonotify(desc, val);
191 if (ret)
192 return ret;
193 } else {
194 ret = gpiod_direction_input_nonotify(desc);
195 if (ret)
196 return ret;
197 }
198
199 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
200 }
201 return 0;
202 }
203
linehandle_ioctl(struct file * file,unsigned int cmd,unsigned long arg)204 static long linehandle_ioctl(struct file *file, unsigned int cmd,
205 unsigned long arg)
206 {
207 struct linehandle_state *lh = file->private_data;
208 void __user *ip = (void __user *)arg;
209 struct gpiohandle_data ghd;
210 DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
211 unsigned int i;
212 int ret;
213
214 guard(srcu)(&lh->gdev->srcu);
215
216 if (!rcu_access_pointer(lh->gdev->chip))
217 return -ENODEV;
218
219 switch (cmd) {
220 case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
221 /* NOTE: It's okay to read values of output lines */
222 ret = gpiod_get_array_value_complex(false, true,
223 lh->num_descs, lh->descs,
224 NULL, vals);
225 if (ret)
226 return ret;
227
228 memset(&ghd, 0, sizeof(ghd));
229 for (i = 0; i < lh->num_descs; i++)
230 ghd.values[i] = test_bit(i, vals);
231
232 if (copy_to_user(ip, &ghd, sizeof(ghd)))
233 return -EFAULT;
234
235 return 0;
236 case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
237 /*
238 * All line descriptors were created at once with the same
239 * flags so just check if the first one is really output.
240 */
241 if (!test_bit(GPIOD_FLAG_IS_OUT, &lh->descs[0]->flags))
242 return -EPERM;
243
244 if (copy_from_user(&ghd, ip, sizeof(ghd)))
245 return -EFAULT;
246
247 /* Clamp all values to [0,1] */
248 for (i = 0; i < lh->num_descs; i++)
249 __assign_bit(i, vals, ghd.values[i]);
250
251 /* Reuse the array setting function */
252 return gpiod_set_array_value_complex(false,
253 true,
254 lh->num_descs,
255 lh->descs,
256 NULL,
257 vals);
258 case GPIOHANDLE_SET_CONFIG_IOCTL:
259 return linehandle_set_config(lh, ip);
260 default:
261 return -EINVAL;
262 }
263 }
264
265 #ifdef CONFIG_COMPAT
linehandle_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)266 static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
267 unsigned long arg)
268 {
269 return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
270 }
271 #endif
272
linehandle_free(struct linehandle_state * lh)273 static void linehandle_free(struct linehandle_state *lh)
274 {
275 int i;
276
277 for (i = 0; i < lh->num_descs; i++)
278 if (lh->descs[i])
279 gpiod_free(lh->descs[i]);
280 kfree(lh->label);
281 gpio_device_put(lh->gdev);
282 kfree(lh);
283 }
284
linehandle_release(struct inode * inode,struct file * file)285 static int linehandle_release(struct inode *inode, struct file *file)
286 {
287 linehandle_free(file->private_data);
288 return 0;
289 }
290
291 static const struct file_operations linehandle_fileops = {
292 .release = linehandle_release,
293 .owner = THIS_MODULE,
294 .llseek = noop_llseek,
295 .unlocked_ioctl = linehandle_ioctl,
296 #ifdef CONFIG_COMPAT
297 .compat_ioctl = linehandle_ioctl_compat,
298 #endif
299 };
300
301 DEFINE_FREE(linehandle_free, struct linehandle_state *, if (!IS_ERR_OR_NULL(_T)) linehandle_free(_T))
302
linehandle_create(struct gpio_device * gdev,void __user * ip)303 static int linehandle_create(struct gpio_device *gdev, void __user *ip)
304 {
305 struct gpiohandle_request handlereq;
306 struct linehandle_state *lh __free(linehandle_free) = NULL;
307 int i, ret;
308 u32 lflags;
309
310 if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
311 return -EFAULT;
312 if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
313 return -EINVAL;
314
315 lflags = handlereq.flags;
316
317 ret = linehandle_validate_flags(lflags);
318 if (ret)
319 return ret;
320
321 lh = kzalloc_obj(*lh);
322 if (!lh)
323 return -ENOMEM;
324 lh->gdev = gpio_device_get(gdev);
325
326 if (handlereq.consumer_label[0] != '\0') {
327 /* label is only initialized if consumer_label is set */
328 lh->label = kstrndup(handlereq.consumer_label,
329 sizeof(handlereq.consumer_label) - 1,
330 GFP_KERNEL);
331 if (!lh->label)
332 return -ENOMEM;
333 }
334
335 lh->num_descs = handlereq.lines;
336
337 /* Request each GPIO */
338 for (i = 0; i < handlereq.lines; i++) {
339 u32 offset = handlereq.lineoffsets[i];
340 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
341
342 if (IS_ERR(desc))
343 return PTR_ERR(desc);
344
345 ret = gpiod_request_user(desc, lh->label);
346 if (ret)
347 return ret;
348 lh->descs[i] = desc;
349 linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
350
351 ret = gpiod_set_transitory(desc, false);
352 if (ret < 0)
353 return ret;
354
355 /*
356 * Lines have to be requested explicitly for input
357 * or output, else the line will be treated "as is".
358 */
359 if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
360 int val = !!handlereq.default_values[i];
361
362 ret = gpiod_direction_output_nonotify(desc, val);
363 if (ret)
364 return ret;
365 } else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
366 ret = gpiod_direction_input_nonotify(desc);
367 if (ret)
368 return ret;
369 }
370
371 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
372
373 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
374 offset);
375 }
376
377 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
378 anon_inode_getfile("gpio-linehandle", &linehandle_fileops,
379 lh, O_RDONLY | O_CLOEXEC));
380 if (fdf.err)
381 return fdf.err;
382 retain_and_null_ptr(lh);
383
384 handlereq.fd = fd_prepare_fd(fdf);
385 if (copy_to_user(ip, &handlereq, sizeof(handlereq)))
386 return -EFAULT;
387
388 fd_publish(fdf);
389
390 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
391 handlereq.lines);
392
393 return 0;
394 }
395 #endif /* CONFIG_GPIO_CDEV_V1 */
396
397 /**
398 * struct line - contains the state of a requested line
399 * @desc: the GPIO descriptor for this line.
400 * @req: the corresponding line request
401 * @irq: the interrupt triggered in response to events on this GPIO
402 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
403 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
404 * @timestamp_ns: cache for the timestamp storing it between hardirq and
405 * IRQ thread, used to bring the timestamp close to the actual event
406 * @req_seqno: the seqno for the current edge event in the sequence of
407 * events for the corresponding line request. This is drawn from the @req.
408 * @line_seqno: the seqno for the current edge event in the sequence of
409 * events for this line.
410 * @work: the worker that implements software debouncing
411 * @sw_debounced: flag indicating if the software debouncer is active
412 * @level: the current debounced physical level of the line
413 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
414 * @raw_level: the line level at the time of event
415 * @total_discard_seq: the running counter of the discarded events
416 * @last_seqno: the last sequence number before debounce period expires
417 */
418 struct line {
419 struct gpio_desc *desc;
420 /*
421 * -- edge detector specific fields --
422 */
423 struct linereq *req;
424 unsigned int irq;
425 /*
426 * The flags for the active edge detector configuration.
427 *
428 * edflags is set by linereq_create(), linereq_free(), and
429 * linereq_set_config(), which are themselves mutually
430 * exclusive, and is accessed by edge_irq_thread(),
431 * process_hw_ts_thread() and debounce_work_func(),
432 * which can all live with a slightly stale value.
433 */
434 u64 edflags;
435 /*
436 * timestamp_ns and req_seqno are accessed only by
437 * edge_irq_handler() and edge_irq_thread(), which are themselves
438 * mutually exclusive, so no additional protection is necessary.
439 */
440 u64 timestamp_ns;
441 u32 req_seqno;
442 /*
443 * line_seqno is accessed by either edge_irq_thread() or
444 * debounce_work_func(), which are themselves mutually exclusive,
445 * so no additional protection is necessary.
446 */
447 u32 line_seqno;
448 /*
449 * -- debouncer specific fields --
450 */
451 struct delayed_work work;
452 /*
453 * sw_debounce is accessed by linereq_set_config(), which is the
454 * only setter, and linereq_get_values(), which can live with a
455 * slightly stale value.
456 */
457 unsigned int sw_debounced;
458 /*
459 * level is accessed by debounce_work_func(), which is the only
460 * setter, and linereq_get_values() which can live with a slightly
461 * stale value.
462 */
463 unsigned int level;
464 #ifdef CONFIG_HTE
465 struct hte_ts_desc hdesc;
466 /*
467 * HTE provider sets line level at the time of event. The valid
468 * value is 0 or 1 and negative value for an error.
469 */
470 int raw_level;
471 /*
472 * when sw_debounce is set on HTE enabled line, this is running
473 * counter of the discarded events.
474 */
475 u32 total_discard_seq;
476 /*
477 * when sw_debounce is set on HTE enabled line, this variable records
478 * last sequence number before debounce period expires.
479 */
480 u32 last_seqno;
481 #endif /* CONFIG_HTE */
482 };
483
484 /**
485 * struct linereq - contains the state of a userspace line request
486 * @gdev: the GPIO device the line request pertains to
487 * @label: consumer label used to tag GPIO descriptors
488 * @num_lines: the number of lines in the lines array
489 * @wait: wait queue that handles blocking reads of events
490 * @device_unregistered_nb: notifier block for receiving gdev unregister events
491 * @event_buffer_size: the number of elements allocated in @events
492 * @events: KFIFO for the GPIO events
493 * @seqno: the sequence number for edge events generated on all lines in
494 * this line request. Note that this is not used when @num_lines is 1, as
495 * the line_seqno is then the same and is cheaper to calculate.
496 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
497 * of configuration, particularly multi-step accesses to desc flags.
498 * @lines: the lines held by this line request, with @num_lines elements.
499 */
500 struct linereq {
501 struct gpio_device *gdev;
502 const char *label;
503 u32 num_lines;
504 wait_queue_head_t wait;
505 struct notifier_block device_unregistered_nb;
506 u32 event_buffer_size;
507 DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
508 atomic_t seqno;
509 struct mutex config_mutex;
510 struct line lines[] __counted_by(num_lines);
511 };
512
513 #define GPIO_V2_LINE_BIAS_FLAGS \
514 (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
515 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
516 GPIO_V2_LINE_FLAG_BIAS_DISABLED)
517
518 #define GPIO_V2_LINE_DIRECTION_FLAGS \
519 (GPIO_V2_LINE_FLAG_INPUT | \
520 GPIO_V2_LINE_FLAG_OUTPUT)
521
522 #define GPIO_V2_LINE_DRIVE_FLAGS \
523 (GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
524 GPIO_V2_LINE_FLAG_OPEN_SOURCE)
525
526 #define GPIO_V2_LINE_EDGE_FLAGS \
527 (GPIO_V2_LINE_FLAG_EDGE_RISING | \
528 GPIO_V2_LINE_FLAG_EDGE_FALLING)
529
530 #define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS
531
532 #define GPIO_V2_LINE_VALID_FLAGS \
533 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
534 GPIO_V2_LINE_DIRECTION_FLAGS | \
535 GPIO_V2_LINE_DRIVE_FLAGS | \
536 GPIO_V2_LINE_EDGE_FLAGS | \
537 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
538 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
539 GPIO_V2_LINE_BIAS_FLAGS)
540
541 /* subset of flags relevant for edge detector configuration */
542 #define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
543 (GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
544 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
545 GPIO_V2_LINE_EDGE_FLAGS)
546
linereq_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)547 static int linereq_unregistered_notify(struct notifier_block *nb,
548 unsigned long action, void *data)
549 {
550 struct linereq *lr = container_of(nb, struct linereq,
551 device_unregistered_nb);
552
553 wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);
554
555 return NOTIFY_OK;
556 }
557
linereq_put_event(struct linereq * lr,struct gpio_v2_line_event * le)558 static void linereq_put_event(struct linereq *lr,
559 struct gpio_v2_line_event *le)
560 {
561 bool overflow = false;
562
563 scoped_guard(spinlock, &lr->wait.lock) {
564 if (kfifo_is_full(&lr->events)) {
565 overflow = true;
566 kfifo_skip(&lr->events);
567 }
568 kfifo_in(&lr->events, le, 1);
569 }
570 if (!overflow)
571 wake_up_poll(&lr->wait, EPOLLIN);
572 else
573 pr_debug_ratelimited("event FIFO is full - event dropped\n");
574 }
575
line_event_timestamp(struct line * line)576 static u64 line_event_timestamp(struct line *line)
577 {
578 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
579 return ktime_get_real_ns();
580 else if (IS_ENABLED(CONFIG_HTE) &&
581 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
582 return line->timestamp_ns;
583
584 return ktime_get_ns();
585 }
586
line_event_id(int level)587 static u32 line_event_id(int level)
588 {
589 return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
590 GPIO_V2_LINE_EVENT_FALLING_EDGE;
591 }
592
make_irq_label(const char * orig)593 static inline char *make_irq_label(const char *orig)
594 {
595 char *new;
596
597 if (!orig)
598 return NULL;
599
600 new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
601 if (!new)
602 return ERR_PTR(-ENOMEM);
603
604 return new;
605 }
606
free_irq_label(const char * label)607 static inline void free_irq_label(const char *label)
608 {
609 kfree(label);
610 }
611
612 #ifdef CONFIG_HTE
613
process_hw_ts_thread(void * p)614 static enum hte_return process_hw_ts_thread(void *p)
615 {
616 struct line *line;
617 struct linereq *lr;
618 struct gpio_v2_line_event le;
619 u64 edflags;
620 int level;
621
622 if (!p)
623 return HTE_CB_HANDLED;
624
625 line = p;
626 lr = line->req;
627
628 memset(&le, 0, sizeof(le));
629
630 le.timestamp_ns = line->timestamp_ns;
631 edflags = READ_ONCE(line->edflags);
632
633 switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
634 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
635 level = (line->raw_level >= 0) ?
636 line->raw_level :
637 gpiod_get_raw_value_cansleep(line->desc);
638
639 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
640 level = !level;
641
642 le.id = line_event_id(level);
643 break;
644 case GPIO_V2_LINE_FLAG_EDGE_RISING:
645 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
646 break;
647 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
648 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
649 break;
650 default:
651 return HTE_CB_HANDLED;
652 }
653 le.line_seqno = line->line_seqno;
654 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
655 le.offset = gpiod_hwgpio(line->desc);
656
657 linereq_put_event(lr, &le);
658
659 return HTE_CB_HANDLED;
660 }
661
process_hw_ts(struct hte_ts_data * ts,void * p)662 static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
663 {
664 struct line *line;
665 struct linereq *lr;
666 int diff_seqno = 0;
667
668 if (!ts || !p)
669 return HTE_CB_HANDLED;
670
671 line = p;
672 line->timestamp_ns = ts->tsc;
673 line->raw_level = ts->raw_level;
674 lr = line->req;
675
676 if (READ_ONCE(line->sw_debounced)) {
677 line->total_discard_seq++;
678 line->last_seqno = ts->seq;
679 mod_delayed_work(system_percpu_wq, &line->work,
680 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
681 } else {
682 if (unlikely(ts->seq < line->line_seqno))
683 return HTE_CB_HANDLED;
684
685 diff_seqno = ts->seq - line->line_seqno;
686 line->line_seqno = ts->seq;
687 if (lr->num_lines != 1)
688 line->req_seqno = atomic_add_return(diff_seqno,
689 &lr->seqno);
690
691 return HTE_RUN_SECOND_CB;
692 }
693
694 return HTE_CB_HANDLED;
695 }
696
hte_edge_setup(struct line * line,u64 eflags)697 static int hte_edge_setup(struct line *line, u64 eflags)
698 {
699 int ret;
700 unsigned long flags = 0;
701 struct hte_ts_desc *hdesc = &line->hdesc;
702
703 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
704 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
705 HTE_FALLING_EDGE_TS :
706 HTE_RISING_EDGE_TS;
707 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
708 flags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
709 HTE_RISING_EDGE_TS :
710 HTE_FALLING_EDGE_TS;
711
712 line->total_discard_seq = 0;
713
714 hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
715 line->desc);
716
717 ret = hte_ts_get(NULL, hdesc, 0);
718 if (ret)
719 return ret;
720
721 return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
722 line);
723 }
724
725 #else
726
hte_edge_setup(struct line * line,u64 eflags)727 static int hte_edge_setup(struct line *line, u64 eflags)
728 {
729 return 0;
730 }
731 #endif /* CONFIG_HTE */
732
edge_irq_thread(int irq,void * p)733 static irqreturn_t edge_irq_thread(int irq, void *p)
734 {
735 struct line *line = p;
736 struct linereq *lr = line->req;
737 struct gpio_v2_line_event le;
738
739 /* Do not leak kernel stack to userspace */
740 memset(&le, 0, sizeof(le));
741
742 if (line->timestamp_ns) {
743 le.timestamp_ns = line->timestamp_ns;
744 } else {
745 /*
746 * We may be running from a nested threaded interrupt in
747 * which case we didn't get the timestamp from
748 * edge_irq_handler().
749 */
750 le.timestamp_ns = line_event_timestamp(line);
751 if (lr->num_lines != 1)
752 line->req_seqno = atomic_inc_return(&lr->seqno);
753 }
754 line->timestamp_ns = 0;
755
756 switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
757 case GPIO_V2_LINE_FLAG_EDGE_BOTH:
758 le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
759 break;
760 case GPIO_V2_LINE_FLAG_EDGE_RISING:
761 le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
762 break;
763 case GPIO_V2_LINE_FLAG_EDGE_FALLING:
764 le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
765 break;
766 default:
767 return IRQ_NONE;
768 }
769 line->line_seqno++;
770 le.line_seqno = line->line_seqno;
771 le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
772 le.offset = gpiod_hwgpio(line->desc);
773
774 linereq_put_event(lr, &le);
775
776 return IRQ_HANDLED;
777 }
778
edge_irq_handler(int irq,void * p)779 static irqreturn_t edge_irq_handler(int irq, void *p)
780 {
781 struct line *line = p;
782 struct linereq *lr = line->req;
783
784 /*
785 * Just store the timestamp in hardirq context so we get it as
786 * close in time as possible to the actual event.
787 */
788 line->timestamp_ns = line_event_timestamp(line);
789
790 if (lr->num_lines != 1)
791 line->req_seqno = atomic_inc_return(&lr->seqno);
792
793 return IRQ_WAKE_THREAD;
794 }
795
796 /*
797 * returns the current debounced logical value.
798 */
debounced_value(struct line * line)799 static bool debounced_value(struct line *line)
800 {
801 bool value;
802
803 /*
804 * minor race - debouncer may be stopped here, so edge_detector_stop()
805 * must leave the value unchanged so the following will read the level
806 * from when the debouncer was last running.
807 */
808 value = READ_ONCE(line->level);
809
810 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags))
811 value = !value;
812
813 return value;
814 }
815
debounce_irq_handler(int irq,void * p)816 static irqreturn_t debounce_irq_handler(int irq, void *p)
817 {
818 struct line *line = p;
819
820 mod_delayed_work(system_percpu_wq, &line->work,
821 usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us)));
822
823 return IRQ_HANDLED;
824 }
825
debounce_work_func(struct work_struct * work)826 static void debounce_work_func(struct work_struct *work)
827 {
828 struct gpio_v2_line_event le;
829 struct line *line = container_of(work, struct line, work.work);
830 struct linereq *lr;
831 u64 eflags, edflags = READ_ONCE(line->edflags);
832 int level = -1;
833 #ifdef CONFIG_HTE
834 int diff_seqno;
835
836 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
837 level = line->raw_level;
838 #endif
839 if (level < 0)
840 level = gpiod_get_raw_value_cansleep(line->desc);
841 if (level < 0) {
842 pr_debug_ratelimited("debouncer failed to read line value\n");
843 return;
844 }
845
846 if (READ_ONCE(line->level) == level)
847 return;
848
849 WRITE_ONCE(line->level, level);
850
851 /* -- edge detection -- */
852 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
853 if (!eflags)
854 return;
855
856 /* switch from physical level to logical - if they differ */
857 if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
858 level = !level;
859
860 /* ignore edges that are not being monitored */
861 if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
862 ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
863 return;
864
865 /* Do not leak kernel stack to userspace */
866 memset(&le, 0, sizeof(le));
867
868 lr = line->req;
869 le.timestamp_ns = line_event_timestamp(line);
870 le.offset = gpiod_hwgpio(line->desc);
871 #ifdef CONFIG_HTE
872 if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
873 /* discard events except the last one */
874 line->total_discard_seq -= 1;
875 diff_seqno = line->last_seqno - line->total_discard_seq -
876 line->line_seqno;
877 line->line_seqno = line->last_seqno - line->total_discard_seq;
878 le.line_seqno = line->line_seqno;
879 le.seqno = (lr->num_lines == 1) ?
880 le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
881 } else
882 #endif /* CONFIG_HTE */
883 {
884 line->line_seqno++;
885 le.line_seqno = line->line_seqno;
886 le.seqno = (lr->num_lines == 1) ?
887 le.line_seqno : atomic_inc_return(&lr->seqno);
888 }
889
890 le.id = line_event_id(level);
891
892 linereq_put_event(lr, &le);
893 }
894
debounce_setup(struct line * line,unsigned int debounce_period_us)895 static int debounce_setup(struct line *line, unsigned int debounce_period_us)
896 {
897 unsigned long irqflags;
898 int ret, level, irq;
899 char *label;
900
901 /*
902 * Try hardware. Skip gpiod_set_config() to avoid emitting two
903 * CHANGED_CONFIG line state events.
904 */
905 ret = gpio_do_set_config(line->desc,
906 pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE,
907 debounce_period_us));
908 if (ret != -ENOTSUPP)
909 return ret;
910
911 if (debounce_period_us) {
912 /* setup software debounce */
913 level = gpiod_get_raw_value_cansleep(line->desc);
914 if (level < 0)
915 return level;
916
917 if (!(IS_ENABLED(CONFIG_HTE) &&
918 test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
919 irq = gpiod_to_irq(line->desc);
920 if (irq < 0)
921 return -ENXIO;
922
923 label = make_irq_label(line->req->label);
924 if (IS_ERR(label))
925 return -ENOMEM;
926
927 irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
928 ret = request_irq(irq, debounce_irq_handler, irqflags,
929 label, line);
930 if (ret) {
931 free_irq_label(label);
932 return ret;
933 }
934 line->irq = irq;
935 } else {
936 ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
937 if (ret)
938 return ret;
939 }
940
941 WRITE_ONCE(line->level, level);
942 WRITE_ONCE(line->sw_debounced, 1);
943 }
944 return 0;
945 }
946
gpio_v2_line_config_debounced(struct gpio_v2_line_config * lc,unsigned int line_idx)947 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
948 unsigned int line_idx)
949 {
950 unsigned int i;
951 u64 mask = BIT_ULL(line_idx);
952
953 for (i = 0; i < lc->num_attrs; i++) {
954 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
955 (lc->attrs[i].mask & mask))
956 return true;
957 }
958 return false;
959 }
960
gpio_v2_line_config_debounce_period(struct gpio_v2_line_config * lc,unsigned int line_idx)961 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
962 unsigned int line_idx)
963 {
964 unsigned int i;
965 u64 mask = BIT_ULL(line_idx);
966
967 for (i = 0; i < lc->num_attrs; i++) {
968 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
969 (lc->attrs[i].mask & mask))
970 return lc->attrs[i].attr.debounce_period_us;
971 }
972 return 0;
973 }
974
edge_detector_stop(struct line * line)975 static void edge_detector_stop(struct line *line)
976 {
977 if (line->irq) {
978 free_irq_label(free_irq(line->irq, line));
979 line->irq = 0;
980 }
981
982 #ifdef CONFIG_HTE
983 if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
984 hte_ts_put(&line->hdesc);
985 #endif
986
987 cancel_delayed_work_sync(&line->work);
988 WRITE_ONCE(line->sw_debounced, 0);
989 WRITE_ONCE(line->edflags, 0);
990 if (line->desc)
991 WRITE_ONCE(line->desc->debounce_period_us, 0);
992 /* do not change line->level - see comment in debounced_value() */
993 }
994
edge_detector_fifo_init(struct linereq * req)995 static int edge_detector_fifo_init(struct linereq *req)
996 {
997 if (kfifo_initialized(&req->events))
998 return 0;
999
1000 return kfifo_alloc(&req->events, req->event_buffer_size, GFP_KERNEL);
1001 }
1002
edge_detector_setup(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 edflags)1003 static int edge_detector_setup(struct line *line,
1004 struct gpio_v2_line_config *lc,
1005 unsigned int line_idx, u64 edflags)
1006 {
1007 u32 debounce_period_us;
1008 unsigned long irqflags = 0;
1009 u64 eflags;
1010 int irq, ret;
1011 char *label;
1012
1013 eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
1014 if (eflags) {
1015 ret = edge_detector_fifo_init(line->req);
1016 if (ret)
1017 return ret;
1018 }
1019 if (gpio_v2_line_config_debounced(lc, line_idx)) {
1020 debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
1021 ret = debounce_setup(line, debounce_period_us);
1022 if (ret)
1023 return ret;
1024 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1025 }
1026
1027 /* detection disabled or sw debouncer will provide edge detection */
1028 if (!eflags || READ_ONCE(line->sw_debounced))
1029 return 0;
1030
1031 if (IS_ENABLED(CONFIG_HTE) &&
1032 (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1033 return hte_edge_setup(line, edflags);
1034
1035 irq = gpiod_to_irq(line->desc);
1036 if (irq < 0)
1037 return -ENXIO;
1038
1039 if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
1040 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
1041 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
1042 if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
1043 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &line->desc->flags) ?
1044 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
1045 irqflags |= IRQF_ONESHOT;
1046
1047 label = make_irq_label(line->req->label);
1048 if (IS_ERR(label))
1049 return PTR_ERR(label);
1050
1051 /* Request a thread to read the events */
1052 ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
1053 irqflags, label, line);
1054 if (ret) {
1055 free_irq_label(label);
1056 return ret;
1057 }
1058
1059 line->irq = irq;
1060 return 0;
1061 }
1062
edge_detector_update(struct line * line,struct gpio_v2_line_config * lc,unsigned int line_idx,u64 edflags)1063 static int edge_detector_update(struct line *line,
1064 struct gpio_v2_line_config *lc,
1065 unsigned int line_idx, u64 edflags)
1066 {
1067 u64 active_edflags = READ_ONCE(line->edflags);
1068 unsigned int debounce_period_us =
1069 gpio_v2_line_config_debounce_period(lc, line_idx);
1070
1071 if ((active_edflags == edflags) &&
1072 (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us))
1073 return 0;
1074
1075 /* sw debounced and still will be...*/
1076 if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
1077 WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us);
1078 /*
1079 * ensure event fifo is initialised if edge detection
1080 * is now enabled.
1081 */
1082 if (edflags & GPIO_V2_LINE_EDGE_FLAGS)
1083 return edge_detector_fifo_init(line->req);
1084
1085 return 0;
1086 }
1087
1088 /* reconfiguring edge detection or sw debounce being disabled */
1089 if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
1090 (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
1091 (!debounce_period_us && READ_ONCE(line->sw_debounced)))
1092 edge_detector_stop(line);
1093
1094 return edge_detector_setup(line, lc, line_idx, edflags);
1095 }
1096
gpio_v2_line_config_flags(struct gpio_v2_line_config * lc,unsigned int line_idx)1097 static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
1098 unsigned int line_idx)
1099 {
1100 unsigned int i;
1101 u64 mask = BIT_ULL(line_idx);
1102
1103 for (i = 0; i < lc->num_attrs; i++) {
1104 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
1105 (lc->attrs[i].mask & mask))
1106 return lc->attrs[i].attr.flags;
1107 }
1108 return lc->flags;
1109 }
1110
gpio_v2_line_config_output_value(struct gpio_v2_line_config * lc,unsigned int line_idx)1111 static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
1112 unsigned int line_idx)
1113 {
1114 unsigned int i;
1115 u64 mask = BIT_ULL(line_idx);
1116
1117 for (i = 0; i < lc->num_attrs; i++) {
1118 if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
1119 (lc->attrs[i].mask & mask))
1120 return !!(lc->attrs[i].attr.values & mask);
1121 }
1122 return 0;
1123 }
1124
gpio_v2_line_flags_validate(u64 flags)1125 static int gpio_v2_line_flags_validate(u64 flags)
1126 {
1127 /* Return an error if an unknown flag is set */
1128 if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
1129 return -EINVAL;
1130
1131 if (!IS_ENABLED(CONFIG_HTE) &&
1132 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1133 return -EOPNOTSUPP;
1134
1135 /*
1136 * Do not allow both INPUT and OUTPUT flags to be set as they are
1137 * contradictory.
1138 */
1139 if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
1140 (flags & GPIO_V2_LINE_FLAG_OUTPUT))
1141 return -EINVAL;
1142
1143 /* Only allow one event clock source */
1144 if (IS_ENABLED(CONFIG_HTE) &&
1145 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
1146 (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
1147 return -EINVAL;
1148
1149 /* Edge detection requires explicit input. */
1150 if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
1151 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1152 return -EINVAL;
1153
1154 /*
1155 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
1156 * request. If the hardware actually supports enabling both at the
1157 * same time the electrical result would be disastrous.
1158 */
1159 if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
1160 (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
1161 return -EINVAL;
1162
1163 /* Drive requires explicit output direction. */
1164 if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
1165 !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
1166 return -EINVAL;
1167
1168 /* Bias requires explicit direction. */
1169 if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
1170 !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1171 return -EINVAL;
1172
1173 /* Only one bias flag can be set. */
1174 if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
1175 (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
1176 GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
1177 ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
1178 (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
1179 return -EINVAL;
1180
1181 return 0;
1182 }
1183
gpio_v2_line_config_validate(struct gpio_v2_line_config * lc,unsigned int num_lines)1184 static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
1185 unsigned int num_lines)
1186 {
1187 size_t unused_attrs;
1188 unsigned int i;
1189 u64 flags;
1190 int ret;
1191
1192 if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
1193 return -EINVAL;
1194
1195 unused_attrs = GPIO_V2_LINE_NUM_ATTRS_MAX - lc->num_attrs;
1196
1197 if (!mem_is_zero(lc->padding, sizeof(lc->padding)))
1198 return -EINVAL;
1199
1200 for (i = 0; i < lc->num_attrs; i++) {
1201 if (lc->attrs[i].attr.padding != 0)
1202 return -EINVAL;
1203 }
1204
1205 if (unused_attrs) {
1206 if (!mem_is_zero(&lc->attrs[lc->num_attrs], unused_attrs * sizeof(*lc->attrs)))
1207 return -EINVAL;
1208 }
1209
1210 for (i = 0; i < num_lines; i++) {
1211 flags = gpio_v2_line_config_flags(lc, i);
1212 ret = gpio_v2_line_flags_validate(flags);
1213 if (ret)
1214 return ret;
1215
1216 /* debounce requires explicit input */
1217 if (gpio_v2_line_config_debounced(lc, i) &&
1218 !(flags & GPIO_V2_LINE_FLAG_INPUT))
1219 return -EINVAL;
1220 }
1221 return 0;
1222 }
1223
gpio_v2_line_config_flags_to_desc_flags(u64 lflags,unsigned long * flagsp)1224 static void gpio_v2_line_config_flags_to_desc_flags(u64 lflags,
1225 unsigned long *flagsp)
1226 {
1227 unsigned long flags = READ_ONCE(*flagsp);
1228
1229 assign_bit(GPIOD_FLAG_ACTIVE_LOW, &flags,
1230 lflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);
1231
1232 if (lflags & GPIO_V2_LINE_FLAG_OUTPUT)
1233 set_bit(GPIOD_FLAG_IS_OUT, &flags);
1234 else if (lflags & GPIO_V2_LINE_FLAG_INPUT)
1235 clear_bit(GPIOD_FLAG_IS_OUT, &flags);
1236
1237 assign_bit(GPIOD_FLAG_EDGE_RISING, &flags,
1238 lflags & GPIO_V2_LINE_FLAG_EDGE_RISING);
1239 assign_bit(GPIOD_FLAG_EDGE_FALLING, &flags,
1240 lflags & GPIO_V2_LINE_FLAG_EDGE_FALLING);
1241
1242 assign_bit(GPIOD_FLAG_OPEN_DRAIN, &flags,
1243 lflags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
1244 assign_bit(GPIOD_FLAG_OPEN_SOURCE, &flags,
1245 lflags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);
1246
1247 assign_bit(GPIOD_FLAG_PULL_UP, &flags,
1248 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
1249 assign_bit(GPIOD_FLAG_PULL_DOWN, &flags,
1250 lflags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
1251 assign_bit(GPIOD_FLAG_BIAS_DISABLE, &flags,
1252 lflags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);
1253
1254 assign_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &flags,
1255 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
1256 assign_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &flags,
1257 lflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
1258
1259 WRITE_ONCE(*flagsp, flags);
1260 }
1261
linereq_get_values(struct linereq * lr,void __user * ip)1262 static long linereq_get_values(struct linereq *lr, void __user *ip)
1263 {
1264 struct gpio_v2_line_values lv;
1265 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1266 struct gpio_desc **descs;
1267 unsigned int i, didx, num_get;
1268 bool val;
1269 int ret;
1270
1271 /* NOTE: It's ok to read values of output lines. */
1272 if (copy_from_user(&lv, ip, sizeof(lv)))
1273 return -EFAULT;
1274
1275 /*
1276 * gpiod_get_array_value_complex() requires compacted desc and val
1277 * arrays, rather than the sparse ones in lv.
1278 * Calculation of num_get and construction of the desc array is
1279 * optimized to avoid allocation for the desc array for the common
1280 * num_get == 1 case.
1281 */
1282 /* scan requested lines to calculate the subset to get */
1283 for (num_get = 0, i = 0; i < lr->num_lines; i++) {
1284 if (lv.mask & BIT_ULL(i)) {
1285 num_get++;
1286 /* capture desc for the num_get == 1 case */
1287 descs = &lr->lines[i].desc;
1288 }
1289 }
1290
1291 if (num_get == 0)
1292 return -EINVAL;
1293
1294 if (num_get != 1) {
1295 /* build compacted desc array */
1296 descs = kmalloc_objs(*descs, num_get);
1297 if (!descs)
1298 return -ENOMEM;
1299 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1300 if (lv.mask & BIT_ULL(i)) {
1301 descs[didx] = lr->lines[i].desc;
1302 didx++;
1303 }
1304 }
1305 }
1306 ret = gpiod_get_array_value_complex(false, true, num_get,
1307 descs, NULL, vals);
1308
1309 if (num_get != 1)
1310 kfree(descs);
1311 if (ret)
1312 return ret;
1313
1314 lv.bits = 0;
1315 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1316 /* unpack compacted vals for the response */
1317 if (lv.mask & BIT_ULL(i)) {
1318 if (lr->lines[i].sw_debounced)
1319 val = debounced_value(&lr->lines[i]);
1320 else
1321 val = test_bit(didx, vals);
1322 if (val)
1323 lv.bits |= BIT_ULL(i);
1324 didx++;
1325 }
1326 }
1327
1328 if (copy_to_user(ip, &lv, sizeof(lv)))
1329 return -EFAULT;
1330
1331 return 0;
1332 }
1333
linereq_set_values(struct linereq * lr,void __user * ip)1334 static long linereq_set_values(struct linereq *lr, void __user *ip)
1335 {
1336 DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
1337 struct gpio_v2_line_values lv;
1338 struct gpio_desc **descs;
1339 unsigned int i, didx, num_set;
1340 int ret;
1341
1342 if (copy_from_user(&lv, ip, sizeof(lv)))
1343 return -EFAULT;
1344
1345 guard(mutex)(&lr->config_mutex);
1346
1347 /*
1348 * gpiod_set_array_value_complex() requires compacted desc and val
1349 * arrays, rather than the sparse ones in lv.
1350 * Calculation of num_set and construction of the descs and vals arrays
1351 * is optimized to minimize scanning the lv->mask, and to avoid
1352 * allocation for the desc array for the common num_set == 1 case.
1353 */
1354 bitmap_zero(vals, GPIO_V2_LINES_MAX);
1355 /* scan requested lines to determine the subset to be set */
1356 for (num_set = 0, i = 0; i < lr->num_lines; i++) {
1357 if (lv.mask & BIT_ULL(i)) {
1358 /* add to compacted values */
1359 if (lv.bits & BIT_ULL(i))
1360 __set_bit(num_set, vals);
1361 num_set++;
1362 /* capture desc for the num_set == 1 case */
1363 descs = &lr->lines[i].desc;
1364 }
1365 }
1366 if (num_set == 0)
1367 return -EINVAL;
1368
1369 if (num_set != 1) {
1370 /* build compacted desc array */
1371 descs = kmalloc_objs(*descs, num_set);
1372 if (!descs)
1373 return -ENOMEM;
1374 for (didx = 0, i = 0; i < lr->num_lines; i++) {
1375 if (lv.mask & BIT_ULL(i)) {
1376 descs[didx] = lr->lines[i].desc;
1377 didx++;
1378 }
1379 }
1380 }
1381 ret = gpiod_set_array_value_complex(false, true, num_set,
1382 descs, NULL, vals);
1383
1384 if (num_set != 1)
1385 kfree(descs);
1386 return ret;
1387 }
1388
linereq_set_config(struct linereq * lr,void __user * ip)1389 static long linereq_set_config(struct linereq *lr, void __user *ip)
1390 {
1391 struct gpio_v2_line_config lc;
1392 struct gpio_desc *desc;
1393 struct line *line;
1394 unsigned int i;
1395 u64 flags, edflags;
1396 int ret;
1397
1398 if (copy_from_user(&lc, ip, sizeof(lc)))
1399 return -EFAULT;
1400
1401 ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
1402 if (ret)
1403 return ret;
1404
1405 guard(mutex)(&lr->config_mutex);
1406
1407 for (i = 0; i < lr->num_lines; i++) {
1408 line = &lr->lines[i];
1409 desc = lr->lines[i].desc;
1410 flags = gpio_v2_line_config_flags(&lc, i);
1411 /*
1412 * Lines not explicitly reconfigured as input or output
1413 * are left unchanged.
1414 */
1415 if (!(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
1416 continue;
1417 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1418 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1419 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1420 int val = gpio_v2_line_config_output_value(&lc, i);
1421
1422 edge_detector_stop(line);
1423 ret = gpiod_direction_output_nonotify(desc, val);
1424 if (ret)
1425 return ret;
1426 } else {
1427 ret = gpiod_direction_input_nonotify(desc);
1428 if (ret)
1429 return ret;
1430
1431 ret = edge_detector_update(line, &lc, i, edflags);
1432 if (ret)
1433 return ret;
1434 }
1435
1436 WRITE_ONCE(line->edflags, edflags);
1437
1438 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
1439 }
1440 return 0;
1441 }
1442
linereq_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1443 static long linereq_ioctl(struct file *file, unsigned int cmd,
1444 unsigned long arg)
1445 {
1446 struct linereq *lr = file->private_data;
1447 void __user *ip = (void __user *)arg;
1448
1449 guard(srcu)(&lr->gdev->srcu);
1450
1451 if (!rcu_access_pointer(lr->gdev->chip))
1452 return -ENODEV;
1453
1454 switch (cmd) {
1455 case GPIO_V2_LINE_GET_VALUES_IOCTL:
1456 return linereq_get_values(lr, ip);
1457 case GPIO_V2_LINE_SET_VALUES_IOCTL:
1458 return linereq_set_values(lr, ip);
1459 case GPIO_V2_LINE_SET_CONFIG_IOCTL:
1460 return linereq_set_config(lr, ip);
1461 default:
1462 return -EINVAL;
1463 }
1464 }
1465
1466 #ifdef CONFIG_COMPAT
linereq_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1467 static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
1468 unsigned long arg)
1469 {
1470 return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1471 }
1472 #endif
1473
linereq_poll(struct file * file,struct poll_table_struct * wait)1474 static __poll_t linereq_poll(struct file *file,
1475 struct poll_table_struct *wait)
1476 {
1477 struct linereq *lr = file->private_data;
1478 __poll_t events = 0;
1479
1480 guard(srcu)(&lr->gdev->srcu);
1481
1482 if (!rcu_access_pointer(lr->gdev->chip))
1483 return EPOLLHUP | EPOLLERR;
1484
1485 poll_wait(file, &lr->wait, wait);
1486
1487 if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
1488 &lr->wait.lock))
1489 events = EPOLLIN | EPOLLRDNORM;
1490
1491 return events;
1492 }
1493
linereq_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1494 static ssize_t linereq_read(struct file *file, char __user *buf,
1495 size_t count, loff_t *f_ps)
1496 {
1497 struct linereq *lr = file->private_data;
1498 struct gpio_v2_line_event le;
1499 ssize_t bytes_read = 0;
1500 int ret;
1501
1502 guard(srcu)(&lr->gdev->srcu);
1503
1504 if (!rcu_access_pointer(lr->gdev->chip))
1505 return -ENODEV;
1506
1507 if (count < sizeof(le))
1508 return -EINVAL;
1509
1510 do {
1511 scoped_guard(spinlock, &lr->wait.lock) {
1512 if (kfifo_is_empty(&lr->events)) {
1513 if (bytes_read)
1514 return bytes_read;
1515
1516 if (file->f_flags & O_NONBLOCK)
1517 return -EAGAIN;
1518
1519 ret = wait_event_interruptible_locked(lr->wait,
1520 !kfifo_is_empty(&lr->events));
1521 if (ret)
1522 return ret;
1523 }
1524
1525 if (kfifo_out(&lr->events, &le, 1) != 1) {
1526 /*
1527 * This should never happen - we hold the
1528 * lock from the moment we learned the fifo
1529 * is no longer empty until now.
1530 */
1531 WARN(1, "failed to read from non-empty kfifo");
1532 return -EIO;
1533 }
1534 }
1535
1536 if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
1537 return -EFAULT;
1538 bytes_read += sizeof(le);
1539 } while (count >= bytes_read + sizeof(le));
1540
1541 return bytes_read;
1542 }
1543
linereq_free(struct linereq * lr)1544 static void linereq_free(struct linereq *lr)
1545 {
1546 unsigned int i;
1547
1548 if (lr->device_unregistered_nb.notifier_call)
1549 blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
1550 &lr->device_unregistered_nb);
1551
1552 for (i = 0; i < lr->num_lines; i++) {
1553 if (lr->lines[i].desc) {
1554 edge_detector_stop(&lr->lines[i]);
1555 gpiod_free(lr->lines[i].desc);
1556 }
1557 }
1558 kfifo_free(&lr->events);
1559 kfree(lr->label);
1560 gpio_device_put(lr->gdev);
1561 kvfree(lr);
1562 }
1563
linereq_release(struct inode * inode,struct file * file)1564 static int linereq_release(struct inode *inode, struct file *file)
1565 {
1566 struct linereq *lr = file->private_data;
1567
1568 linereq_free(lr);
1569 return 0;
1570 }
1571
1572 #ifdef CONFIG_PROC_FS
linereq_show_fdinfo(struct seq_file * out,struct file * file)1573 static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
1574 {
1575 struct linereq *lr = file->private_data;
1576 struct device *dev = &lr->gdev->dev;
1577 u16 i;
1578
1579 seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));
1580
1581 for (i = 0; i < lr->num_lines; i++)
1582 seq_printf(out, "gpio-line:\t%d\n",
1583 gpiod_hwgpio(lr->lines[i].desc));
1584 }
1585 #endif
1586
1587 static const struct file_operations line_fileops = {
1588 .release = linereq_release,
1589 .read = linereq_read,
1590 .poll = linereq_poll,
1591 .owner = THIS_MODULE,
1592 .llseek = noop_llseek,
1593 .unlocked_ioctl = linereq_ioctl,
1594 #ifdef CONFIG_COMPAT
1595 .compat_ioctl = linereq_ioctl_compat,
1596 #endif
1597 #ifdef CONFIG_PROC_FS
1598 .show_fdinfo = linereq_show_fdinfo,
1599 #endif
1600 };
1601
1602 DEFINE_FREE(linereq_free, struct linereq *, if (!IS_ERR_OR_NULL(_T)) linereq_free(_T))
1603
linereq_create(struct gpio_device * gdev,void __user * ip)1604 static int linereq_create(struct gpio_device *gdev, void __user *ip)
1605 {
1606 struct gpio_v2_line_request ulr;
1607 struct gpio_v2_line_config *lc;
1608 struct linereq *lr __free(linereq_free) = NULL;
1609 u64 flags, edflags;
1610 unsigned int i;
1611 int ret;
1612
1613 if (copy_from_user(&ulr, ip, sizeof(ulr)))
1614 return -EFAULT;
1615
1616 if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
1617 return -EINVAL;
1618
1619 if (!mem_is_zero(ulr.padding, sizeof(ulr.padding)))
1620 return -EINVAL;
1621
1622 lc = &ulr.config;
1623 ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
1624 if (ret)
1625 return ret;
1626
1627 lr = kvzalloc_flex(*lr, lines, ulr.num_lines);
1628 if (!lr)
1629 return -ENOMEM;
1630 lr->num_lines = ulr.num_lines;
1631
1632 lr->gdev = gpio_device_get(gdev);
1633
1634 for (i = 0; i < ulr.num_lines; i++) {
1635 lr->lines[i].req = lr;
1636 WRITE_ONCE(lr->lines[i].sw_debounced, 0);
1637 INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
1638 }
1639
1640 if (ulr.consumer[0] != '\0') {
1641 /* label is only initialized if consumer is set */
1642 lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
1643 GFP_KERNEL);
1644 if (!lr->label)
1645 return -ENOMEM;
1646 }
1647
1648 mutex_init(&lr->config_mutex);
1649 init_waitqueue_head(&lr->wait);
1650 INIT_KFIFO(lr->events);
1651 lr->event_buffer_size = ulr.event_buffer_size;
1652 if (lr->event_buffer_size == 0)
1653 lr->event_buffer_size = ulr.num_lines * 16;
1654 else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
1655 lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;
1656
1657 atomic_set(&lr->seqno, 0);
1658
1659 /* Request each GPIO */
1660 for (i = 0; i < ulr.num_lines; i++) {
1661 u32 offset = ulr.offsets[i];
1662 struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);
1663
1664 if (IS_ERR(desc))
1665 return PTR_ERR(desc);
1666
1667 ret = gpiod_request_user(desc, lr->label);
1668 if (ret)
1669 return ret;
1670
1671 lr->lines[i].desc = desc;
1672 flags = gpio_v2_line_config_flags(lc, i);
1673 gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
1674
1675 ret = gpiod_set_transitory(desc, false);
1676 if (ret < 0)
1677 return ret;
1678
1679 edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
1680 /*
1681 * Lines have to be requested explicitly for input
1682 * or output, else the line will be treated "as is".
1683 */
1684 if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
1685 int val = gpio_v2_line_config_output_value(lc, i);
1686
1687 ret = gpiod_direction_output_nonotify(desc, val);
1688 if (ret)
1689 return ret;
1690 } else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
1691 ret = gpiod_direction_input_nonotify(desc);
1692 if (ret)
1693 return ret;
1694
1695 ret = edge_detector_setup(&lr->lines[i], lc, i,
1696 edflags);
1697 if (ret)
1698 return ret;
1699 }
1700
1701 lr->lines[i].edflags = edflags;
1702
1703 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
1704
1705 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
1706 offset);
1707 }
1708
1709 lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
1710 ret = blocking_notifier_chain_register(&gdev->device_notifier,
1711 &lr->device_unregistered_nb);
1712 if (ret)
1713 return ret;
1714
1715 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
1716 anon_inode_getfile("gpio-line", &line_fileops, lr,
1717 O_RDONLY | O_CLOEXEC));
1718 if (fdf.err)
1719 return fdf.err;
1720 retain_and_null_ptr(lr);
1721
1722 ulr.fd = fd_prepare_fd(fdf);
1723 if (copy_to_user(ip, &ulr, sizeof(ulr)))
1724 return -EFAULT;
1725
1726 fd_publish(fdf);
1727
1728 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
1729 ulr.num_lines);
1730
1731 return 0;
1732 }
1733
1734 #ifdef CONFIG_GPIO_CDEV_V1
1735
1736 /*
1737 * GPIO line event management
1738 */
1739
1740 /**
1741 * struct lineevent_state - contains the state of a userspace event
1742 * @gdev: the GPIO device the event pertains to
1743 * @label: consumer label used to tag descriptors
1744 * @desc: the GPIO descriptor held by this event
1745 * @eflags: the event flags this line was requested with
1746 * @irq: the interrupt that trigger in response to events on this GPIO
1747 * @wait: wait queue that handles blocking reads of events
1748 * @device_unregistered_nb: notifier block for receiving gdev unregister events
1749 * @events: KFIFO for the GPIO events
1750 * @timestamp: cache for the timestamp storing it between hardirq
1751 * and IRQ thread, used to bring the timestamp close to the actual
1752 * event
1753 */
1754 struct lineevent_state {
1755 struct gpio_device *gdev;
1756 const char *label;
1757 struct gpio_desc *desc;
1758 u32 eflags;
1759 int irq;
1760 wait_queue_head_t wait;
1761 struct notifier_block device_unregistered_nb;
1762 DECLARE_KFIFO(events, struct gpioevent_data, 16);
1763 u64 timestamp;
1764 };
1765
1766 #define GPIOEVENT_REQUEST_VALID_FLAGS \
1767 (GPIOEVENT_REQUEST_RISING_EDGE | \
1768 GPIOEVENT_REQUEST_FALLING_EDGE)
1769
lineevent_poll(struct file * file,struct poll_table_struct * wait)1770 static __poll_t lineevent_poll(struct file *file,
1771 struct poll_table_struct *wait)
1772 {
1773 struct lineevent_state *le = file->private_data;
1774 __poll_t events = 0;
1775
1776 guard(srcu)(&le->gdev->srcu);
1777
1778 if (!rcu_access_pointer(le->gdev->chip))
1779 return EPOLLHUP | EPOLLERR;
1780
1781 poll_wait(file, &le->wait, wait);
1782
1783 if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
1784 events = EPOLLIN | EPOLLRDNORM;
1785
1786 return events;
1787 }
1788
lineevent_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)1789 static int lineevent_unregistered_notify(struct notifier_block *nb,
1790 unsigned long action, void *data)
1791 {
1792 struct lineevent_state *le = container_of(nb, struct lineevent_state,
1793 device_unregistered_nb);
1794
1795 wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);
1796
1797 return NOTIFY_OK;
1798 }
1799
1800 struct compat_gpioeevent_data {
1801 compat_u64 timestamp;
1802 u32 id;
1803 };
1804
lineevent_read(struct file * file,char __user * buf,size_t count,loff_t * f_ps)1805 static ssize_t lineevent_read(struct file *file, char __user *buf,
1806 size_t count, loff_t *f_ps)
1807 {
1808 struct lineevent_state *le = file->private_data;
1809 struct gpioevent_data ge;
1810 ssize_t bytes_read = 0;
1811 ssize_t ge_size;
1812 int ret;
1813
1814 guard(srcu)(&le->gdev->srcu);
1815
1816 if (!rcu_access_pointer(le->gdev->chip))
1817 return -ENODEV;
1818
1819 /*
1820 * When compatible system call is being used the struct gpioevent_data,
1821 * in case of at least ia32, has different size due to the alignment
1822 * differences. Because we have first member 64 bits followed by one of
1823 * 32 bits there is no gap between them. The only difference is the
1824 * padding at the end of the data structure. Hence, we calculate the
1825 * actual sizeof() and pass this as an argument to copy_to_user() to
1826 * drop unneeded bytes from the output.
1827 */
1828 if (compat_need_64bit_alignment_fixup())
1829 ge_size = sizeof(struct compat_gpioeevent_data);
1830 else
1831 ge_size = sizeof(struct gpioevent_data);
1832 if (count < ge_size)
1833 return -EINVAL;
1834
1835 do {
1836 scoped_guard(spinlock, &le->wait.lock) {
1837 if (kfifo_is_empty(&le->events)) {
1838 if (bytes_read)
1839 return bytes_read;
1840
1841 if (file->f_flags & O_NONBLOCK)
1842 return -EAGAIN;
1843
1844 ret = wait_event_interruptible_locked(le->wait,
1845 !kfifo_is_empty(&le->events));
1846 if (ret)
1847 return ret;
1848 }
1849
1850 if (kfifo_out(&le->events, &ge, 1) != 1) {
1851 /*
1852 * This should never happen - we hold the
1853 * lock from the moment we learned the fifo
1854 * is no longer empty until now.
1855 */
1856 WARN(1, "failed to read from non-empty kfifo");
1857 return -EIO;
1858 }
1859 }
1860
1861 if (copy_to_user(buf + bytes_read, &ge, ge_size))
1862 return -EFAULT;
1863 bytes_read += ge_size;
1864 } while (count >= bytes_read + ge_size);
1865
1866 return bytes_read;
1867 }
1868
lineevent_free(struct lineevent_state * le)1869 static void lineevent_free(struct lineevent_state *le)
1870 {
1871 if (le->device_unregistered_nb.notifier_call)
1872 blocking_notifier_chain_unregister(&le->gdev->device_notifier,
1873 &le->device_unregistered_nb);
1874 if (le->irq)
1875 free_irq_label(free_irq(le->irq, le));
1876 if (le->desc)
1877 gpiod_free(le->desc);
1878 kfree(le->label);
1879 gpio_device_put(le->gdev);
1880 kfree(le);
1881 }
1882
lineevent_release(struct inode * inode,struct file * file)1883 static int lineevent_release(struct inode *inode, struct file *file)
1884 {
1885 lineevent_free(file->private_data);
1886 return 0;
1887 }
1888
lineevent_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1889 static long lineevent_ioctl(struct file *file, unsigned int cmd,
1890 unsigned long arg)
1891 {
1892 struct lineevent_state *le = file->private_data;
1893 void __user *ip = (void __user *)arg;
1894 struct gpiohandle_data ghd;
1895
1896 guard(srcu)(&le->gdev->srcu);
1897
1898 if (!rcu_access_pointer(le->gdev->chip))
1899 return -ENODEV;
1900
1901 /*
1902 * We can get the value for an event line but not set it,
1903 * because it is input by definition.
1904 */
1905 if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
1906 int val;
1907
1908 memset(&ghd, 0, sizeof(ghd));
1909
1910 val = gpiod_get_value_cansleep(le->desc);
1911 if (val < 0)
1912 return val;
1913 ghd.values[0] = val;
1914
1915 if (copy_to_user(ip, &ghd, sizeof(ghd)))
1916 return -EFAULT;
1917
1918 return 0;
1919 }
1920 return -EINVAL;
1921 }
1922
1923 #ifdef CONFIG_COMPAT
lineevent_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)1924 static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
1925 unsigned long arg)
1926 {
1927 return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1928 }
1929 #endif
1930
1931 static const struct file_operations lineevent_fileops = {
1932 .release = lineevent_release,
1933 .read = lineevent_read,
1934 .poll = lineevent_poll,
1935 .owner = THIS_MODULE,
1936 .llseek = noop_llseek,
1937 .unlocked_ioctl = lineevent_ioctl,
1938 #ifdef CONFIG_COMPAT
1939 .compat_ioctl = lineevent_ioctl_compat,
1940 #endif
1941 };
1942
lineevent_irq_thread(int irq,void * p)1943 static irqreturn_t lineevent_irq_thread(int irq, void *p)
1944 {
1945 struct lineevent_state *le = p;
1946 struct gpioevent_data ge;
1947 int ret;
1948
1949 /* Do not leak kernel stack to userspace */
1950 memset(&ge, 0, sizeof(ge));
1951
1952 /*
1953 * We may be running from a nested threaded interrupt in which case
1954 * we didn't get the timestamp from lineevent_irq_handler().
1955 */
1956 if (!le->timestamp)
1957 ge.timestamp = ktime_get_ns();
1958 else
1959 ge.timestamp = le->timestamp;
1960
1961 if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
1962 && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1963 int level = gpiod_get_value_cansleep(le->desc);
1964
1965 if (level)
1966 /* Emit low-to-high event */
1967 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1968 else
1969 /* Emit high-to-low event */
1970 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1971 } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
1972 /* Emit low-to-high event */
1973 ge.id = GPIOEVENT_EVENT_RISING_EDGE;
1974 } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
1975 /* Emit high-to-low event */
1976 ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
1977 } else {
1978 return IRQ_NONE;
1979 }
1980
1981 ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
1982 1, &le->wait.lock);
1983 if (ret)
1984 wake_up_poll(&le->wait, EPOLLIN);
1985 else
1986 pr_debug_ratelimited("event FIFO is full - event dropped\n");
1987
1988 return IRQ_HANDLED;
1989 }
1990
lineevent_irq_handler(int irq,void * p)1991 static irqreturn_t lineevent_irq_handler(int irq, void *p)
1992 {
1993 struct lineevent_state *le = p;
1994
1995 /*
1996 * Just store the timestamp in hardirq context so we get it as
1997 * close in time as possible to the actual event.
1998 */
1999 le->timestamp = ktime_get_ns();
2000
2001 return IRQ_WAKE_THREAD;
2002 }
2003
2004 DEFINE_FREE(lineevent_free, struct lineevent_state *, if (!IS_ERR_OR_NULL(_T)) lineevent_free(_T))
2005
lineevent_create(struct gpio_device * gdev,void __user * ip)2006 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
2007 {
2008 struct gpioevent_request eventreq;
2009 struct lineevent_state *le __free(lineevent_free) = NULL;
2010 struct gpio_desc *desc;
2011 u32 offset;
2012 u32 lflags;
2013 u32 eflags;
2014 int ret;
2015 int irq, irqflags = 0;
2016 char *label;
2017
2018 if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
2019 return -EFAULT;
2020
2021 offset = eventreq.lineoffset;
2022 lflags = eventreq.handleflags;
2023 eflags = eventreq.eventflags;
2024
2025 desc = gpio_device_get_desc(gdev, offset);
2026 if (IS_ERR(desc))
2027 return PTR_ERR(desc);
2028
2029 /* Return an error if a unknown flag is set */
2030 if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
2031 (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
2032 return -EINVAL;
2033
2034 /* This is just wrong: we don't look for events on output lines */
2035 if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
2036 (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
2037 (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
2038 return -EINVAL;
2039
2040 /* Only one bias flag can be set. */
2041 if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
2042 (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
2043 GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
2044 ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
2045 (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
2046 return -EINVAL;
2047
2048 le = kzalloc_obj(*le);
2049 if (!le)
2050 return -ENOMEM;
2051 le->gdev = gpio_device_get(gdev);
2052
2053 if (eventreq.consumer_label[0] != '\0') {
2054 /* label is only initialized if consumer_label is set */
2055 le->label = kstrndup(eventreq.consumer_label,
2056 sizeof(eventreq.consumer_label) - 1,
2057 GFP_KERNEL);
2058 if (!le->label)
2059 return -ENOMEM;
2060 }
2061
2062 ret = gpiod_request_user(desc, le->label);
2063 if (ret)
2064 return ret;
2065 le->desc = desc;
2066 le->eflags = eflags;
2067
2068 linehandle_flags_to_desc_flags(lflags, &desc->flags);
2069
2070 ret = gpiod_direction_input(desc);
2071 if (ret)
2072 return ret;
2073
2074 gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);
2075
2076 irq = gpiod_to_irq(desc);
2077 if (irq <= 0)
2078 return -ENODEV;
2079
2080 if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
2081 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ?
2082 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
2083 if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
2084 irqflags |= test_bit(GPIOD_FLAG_ACTIVE_LOW, &desc->flags) ?
2085 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
2086 irqflags |= IRQF_ONESHOT;
2087
2088 INIT_KFIFO(le->events);
2089 init_waitqueue_head(&le->wait);
2090
2091 le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
2092 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2093 &le->device_unregistered_nb);
2094 if (ret)
2095 return ret;
2096
2097 label = make_irq_label(le->label);
2098 if (IS_ERR(label))
2099 return PTR_ERR(label);
2100
2101 /* Request a thread to read the events */
2102 ret = request_threaded_irq(irq,
2103 lineevent_irq_handler,
2104 lineevent_irq_thread,
2105 irqflags,
2106 label,
2107 le);
2108 if (ret) {
2109 free_irq_label(label);
2110 return ret;
2111 }
2112
2113 le->irq = irq;
2114
2115 FD_PREPARE(fdf, O_RDONLY | O_CLOEXEC,
2116 anon_inode_getfile("gpio-event", &lineevent_fileops, le,
2117 O_RDONLY | O_CLOEXEC));
2118 if (fdf.err)
2119 return fdf.err;
2120 retain_and_null_ptr(le);
2121
2122 eventreq.fd = fd_prepare_fd(fdf);
2123 if (copy_to_user(ip, &eventreq, sizeof(eventreq)))
2124 return -EFAULT;
2125
2126 fd_publish(fdf);
2127
2128 return 0;
2129 }
2130
gpio_v2_line_info_to_v1(struct gpio_v2_line_info * info_v2,struct gpioline_info * info_v1)2131 static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
2132 struct gpioline_info *info_v1)
2133 {
2134 u64 flagsv2 = info_v2->flags;
2135
2136 memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
2137 memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
2138 info_v1->line_offset = info_v2->offset;
2139 info_v1->flags = 0;
2140
2141 if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
2142 info_v1->flags |= GPIOLINE_FLAG_KERNEL;
2143
2144 if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
2145 info_v1->flags |= GPIOLINE_FLAG_IS_OUT;
2146
2147 if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
2148 info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;
2149
2150 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
2151 info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
2152 if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
2153 info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;
2154
2155 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
2156 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
2157 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
2158 info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
2159 if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
2160 info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
2161 }
2162
gpio_v2_line_info_changed_to_v1(struct gpio_v2_line_info_changed * lic_v2,struct gpioline_info_changed * lic_v1)2163 static void gpio_v2_line_info_changed_to_v1(
2164 struct gpio_v2_line_info_changed *lic_v2,
2165 struct gpioline_info_changed *lic_v1)
2166 {
2167 memset(lic_v1, 0, sizeof(*lic_v1));
2168 gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
2169 lic_v1->timestamp = lic_v2->timestamp_ns;
2170 lic_v1->event_type = lic_v2->event_type;
2171 }
2172
2173 #endif /* CONFIG_GPIO_CDEV_V1 */
2174
gpio_desc_to_lineinfo(struct gpio_desc * desc,struct gpio_v2_line_info * info,bool atomic)2175 static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
2176 struct gpio_v2_line_info *info, bool atomic)
2177 {
2178 u32 debounce_period_us;
2179 unsigned long dflags;
2180 const char *label;
2181
2182 CLASS(gpio_chip_guard, guard)(desc);
2183 if (!guard.gc)
2184 return;
2185
2186 memset(info, 0, sizeof(*info));
2187 info->offset = gpiod_hwgpio(desc);
2188
2189 if (desc->name)
2190 strscpy(info->name, desc->name, sizeof(info->name));
2191
2192 dflags = READ_ONCE(desc->flags);
2193
2194 scoped_guard(srcu, &desc->gdev->desc_srcu) {
2195 label = gpiod_get_label(desc);
2196 if (label && test_bit(GPIOD_FLAG_REQUESTED, &dflags))
2197 strscpy(info->consumer, label,
2198 sizeof(info->consumer));
2199 }
2200
2201 /*
2202 * Userspace only need know that the kernel is using this GPIO so it
2203 * can't use it.
2204 * The calculation of the used flag is slightly racy, as it may read
2205 * desc, gc and pinctrl state without a lock covering all three at
2206 * once. Worst case if the line is in transition and the calculation
2207 * is inconsistent then it looks to the user like they performed the
2208 * read on the other side of the transition - but that can always
2209 * happen.
2210 * The definitive test that a line is available to userspace is to
2211 * request it.
2212 */
2213 if (test_bit(GPIOD_FLAG_REQUESTED, &dflags) ||
2214 test_bit(GPIOD_FLAG_IS_HOGGED, &dflags) ||
2215 test_bit(GPIOD_FLAG_EXPORT, &dflags) ||
2216 test_bit(GPIOD_FLAG_SYSFS, &dflags) ||
2217 !gpiochip_line_is_valid(guard.gc, info->offset)) {
2218 info->flags |= GPIO_V2_LINE_FLAG_USED;
2219 } else if (!atomic) {
2220 if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
2221 info->flags |= GPIO_V2_LINE_FLAG_USED;
2222 }
2223
2224 if (test_bit(GPIOD_FLAG_IS_OUT, &dflags))
2225 info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
2226 else
2227 info->flags |= GPIO_V2_LINE_FLAG_INPUT;
2228
2229 if (test_bit(GPIOD_FLAG_ACTIVE_LOW, &dflags))
2230 info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
2231
2232 if (test_bit(GPIOD_FLAG_OPEN_DRAIN, &dflags))
2233 info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
2234 if (test_bit(GPIOD_FLAG_OPEN_SOURCE, &dflags))
2235 info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
2236
2237 if (test_bit(GPIOD_FLAG_BIAS_DISABLE, &dflags))
2238 info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
2239 if (test_bit(GPIOD_FLAG_PULL_DOWN, &dflags))
2240 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
2241 if (test_bit(GPIOD_FLAG_PULL_UP, &dflags))
2242 info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
2243
2244 if (test_bit(GPIOD_FLAG_EDGE_RISING, &dflags))
2245 info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
2246 if (test_bit(GPIOD_FLAG_EDGE_FALLING, &dflags))
2247 info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
2248
2249 if (test_bit(GPIOD_FLAG_EVENT_CLOCK_REALTIME, &dflags))
2250 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
2251 else if (test_bit(GPIOD_FLAG_EVENT_CLOCK_HTE, &dflags))
2252 info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
2253
2254 debounce_period_us = READ_ONCE(desc->debounce_period_us);
2255 if (debounce_period_us) {
2256 info->attrs[info->num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
2257 info->attrs[info->num_attrs].debounce_period_us =
2258 debounce_period_us;
2259 info->num_attrs++;
2260 }
2261 }
2262
2263 struct gpio_chardev_data {
2264 struct gpio_device *gdev;
2265 wait_queue_head_t wait;
2266 DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
2267 struct notifier_block lineinfo_changed_nb;
2268 struct notifier_block device_unregistered_nb;
2269 unsigned long *watched_lines;
2270 #ifdef CONFIG_GPIO_CDEV_V1
2271 atomic_t watch_abi_version;
2272 #endif
2273 struct file *fp;
2274 };
2275
chipinfo_get(struct gpio_chardev_data * cdev,void __user * ip)2276 static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
2277 {
2278 struct gpio_device *gdev = cdev->gdev;
2279 struct gpiochip_info chipinfo;
2280
2281 memset(&chipinfo, 0, sizeof(chipinfo));
2282
2283 strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
2284 strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
2285 chipinfo.lines = gdev->ngpio;
2286 if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
2287 return -EFAULT;
2288 return 0;
2289 }
2290
2291 #ifdef CONFIG_GPIO_CDEV_V1
2292 /*
2293 * returns 0 if the versions match, else the previously selected ABI version
2294 */
lineinfo_ensure_abi_version(struct gpio_chardev_data * cdata,unsigned int version)2295 static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
2296 unsigned int version)
2297 {
2298 int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);
2299
2300 if (abiv == version)
2301 return 0;
2302
2303 return abiv;
2304 }
2305
lineinfo_get_v1(struct gpio_chardev_data * cdev,void __user * ip,bool watch)2306 static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
2307 bool watch)
2308 {
2309 struct gpio_desc *desc;
2310 struct gpioline_info lineinfo;
2311 struct gpio_v2_line_info lineinfo_v2;
2312
2313 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2314 return -EFAULT;
2315
2316 /* this doubles as a range check on line_offset */
2317 desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset);
2318 if (IS_ERR(desc))
2319 return PTR_ERR(desc);
2320
2321 if (watch) {
2322 if (lineinfo_ensure_abi_version(cdev, 1))
2323 return -EPERM;
2324
2325 if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
2326 return -EBUSY;
2327 }
2328
2329 gpio_desc_to_lineinfo(desc, &lineinfo_v2, false);
2330 gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
2331
2332 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2333 if (watch)
2334 clear_bit(lineinfo.line_offset, cdev->watched_lines);
2335 return -EFAULT;
2336 }
2337
2338 return 0;
2339 }
2340 #endif
2341
lineinfo_get(struct gpio_chardev_data * cdev,void __user * ip,bool watch)2342 static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
2343 bool watch)
2344 {
2345 struct gpio_desc *desc;
2346 struct gpio_v2_line_info lineinfo;
2347
2348 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
2349 return -EFAULT;
2350
2351 if (!mem_is_zero(lineinfo.padding, sizeof(lineinfo.padding)))
2352 return -EINVAL;
2353
2354 desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset);
2355 if (IS_ERR(desc))
2356 return PTR_ERR(desc);
2357
2358 if (watch) {
2359 #ifdef CONFIG_GPIO_CDEV_V1
2360 if (lineinfo_ensure_abi_version(cdev, 2))
2361 return -EPERM;
2362 #endif
2363 if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
2364 return -EBUSY;
2365 }
2366 gpio_desc_to_lineinfo(desc, &lineinfo, false);
2367
2368 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
2369 if (watch)
2370 clear_bit(lineinfo.offset, cdev->watched_lines);
2371 return -EFAULT;
2372 }
2373
2374 return 0;
2375 }
2376
lineinfo_unwatch(struct gpio_chardev_data * cdev,void __user * ip)2377 static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
2378 {
2379 __u32 offset;
2380
2381 if (copy_from_user(&offset, ip, sizeof(offset)))
2382 return -EFAULT;
2383
2384 if (offset >= cdev->gdev->ngpio)
2385 return -EINVAL;
2386
2387 if (!test_and_clear_bit(offset, cdev->watched_lines))
2388 return -EBUSY;
2389
2390 return 0;
2391 }
2392
2393 /*
2394 * gpio_ioctl() - ioctl handler for the GPIO chardev
2395 */
gpio_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2396 static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2397 {
2398 struct gpio_chardev_data *cdev = file->private_data;
2399 struct gpio_device *gdev = cdev->gdev;
2400 void __user *ip = (void __user *)arg;
2401
2402 guard(srcu)(&gdev->srcu);
2403
2404 /* We fail any subsequent ioctl():s when the chip is gone */
2405 if (!rcu_access_pointer(gdev->chip))
2406 return -ENODEV;
2407
2408 /* Fill in the struct and pass to userspace */
2409 switch (cmd) {
2410 case GPIO_GET_CHIPINFO_IOCTL:
2411 return chipinfo_get(cdev, ip);
2412 #ifdef CONFIG_GPIO_CDEV_V1
2413 case GPIO_GET_LINEHANDLE_IOCTL:
2414 return linehandle_create(gdev, ip);
2415 case GPIO_GET_LINEEVENT_IOCTL:
2416 return lineevent_create(gdev, ip);
2417 case GPIO_GET_LINEINFO_IOCTL:
2418 return lineinfo_get_v1(cdev, ip, false);
2419 case GPIO_GET_LINEINFO_WATCH_IOCTL:
2420 return lineinfo_get_v1(cdev, ip, true);
2421 #endif /* CONFIG_GPIO_CDEV_V1 */
2422 case GPIO_V2_GET_LINEINFO_IOCTL:
2423 return lineinfo_get(cdev, ip, false);
2424 case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
2425 return lineinfo_get(cdev, ip, true);
2426 case GPIO_V2_GET_LINE_IOCTL:
2427 return linereq_create(gdev, ip);
2428 case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
2429 return lineinfo_unwatch(cdev, ip);
2430 default:
2431 return -EINVAL;
2432 }
2433 }
2434
2435 #ifdef CONFIG_COMPAT
gpio_ioctl_compat(struct file * file,unsigned int cmd,unsigned long arg)2436 static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
2437 unsigned long arg)
2438 {
2439 return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2440 }
2441 #endif
2442
2443 struct lineinfo_changed_ctx {
2444 struct work_struct work;
2445 struct gpio_v2_line_info_changed chg;
2446 struct gpio_device *gdev;
2447 struct gpio_chardev_data *cdev;
2448 };
2449
lineinfo_changed_func(struct work_struct * work)2450 static void lineinfo_changed_func(struct work_struct *work)
2451 {
2452 struct lineinfo_changed_ctx *ctx =
2453 container_of(work, struct lineinfo_changed_ctx, work);
2454 struct gpio_chip *gc;
2455 int ret;
2456
2457 if (!(ctx->chg.info.flags & GPIO_V2_LINE_FLAG_USED)) {
2458 /*
2459 * If nobody set the USED flag earlier, let's see with pinctrl
2460 * now. We're doing this late because it's a sleeping function.
2461 * Pin functions are in general much more static and while it's
2462 * not 100% bullet-proof, it's good enough for most cases.
2463 */
2464 scoped_guard(srcu, &ctx->gdev->srcu) {
2465 gc = srcu_dereference(ctx->gdev->chip, &ctx->gdev->srcu);
2466 if (gc &&
2467 !pinctrl_gpio_can_use_line(gc, ctx->chg.info.offset))
2468 ctx->chg.info.flags |= GPIO_V2_LINE_FLAG_USED;
2469 }
2470 }
2471
2472 ret = kfifo_in_spinlocked(&ctx->cdev->events, &ctx->chg, 1,
2473 &ctx->cdev->wait.lock);
2474 if (ret)
2475 wake_up_poll(&ctx->cdev->wait, EPOLLIN);
2476 else
2477 pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");
2478
2479 gpio_device_put(ctx->gdev);
2480 fput(ctx->cdev->fp);
2481 kfree(ctx);
2482 }
2483
lineinfo_changed_notify(struct notifier_block * nb,unsigned long action,void * data)2484 static int lineinfo_changed_notify(struct notifier_block *nb,
2485 unsigned long action, void *data)
2486 {
2487 struct gpio_chardev_data *cdev =
2488 container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
2489 struct lineinfo_changed_ctx *ctx;
2490 struct gpio_desc *desc = data;
2491 struct file *fp;
2492
2493 if (!test_bit(gpiod_hwgpio(desc), cdev->watched_lines))
2494 return NOTIFY_DONE;
2495
2496 /* Keep the file descriptor alive for the duration of the notification. */
2497 fp = get_file_active(&cdev->fp);
2498 if (!fp)
2499 /* Chardev file descriptor was or is being released. */
2500 return NOTIFY_DONE;
2501
2502 /*
2503 * If this is called from atomic context (for instance: with a spinlock
2504 * taken by the atomic notifier chain), any sleeping calls must be done
2505 * outside of this function in process context of the dedicated
2506 * workqueue.
2507 *
2508 * Let's gather as much info as possible from the descriptor and
2509 * postpone just the call to pinctrl_gpio_can_use_line() until the work
2510 * is executed.
2511 */
2512
2513 ctx = kzalloc_obj(*ctx, GFP_ATOMIC);
2514 if (!ctx) {
2515 pr_err("Failed to allocate memory for line info notification\n");
2516 fput(fp);
2517 return NOTIFY_DONE;
2518 }
2519
2520 ctx->chg.event_type = action;
2521 ctx->chg.timestamp_ns = ktime_get_ns();
2522 gpio_desc_to_lineinfo(desc, &ctx->chg.info, true);
2523 /* Keep the GPIO device alive until we emit the event. */
2524 ctx->gdev = gpio_device_get(desc->gdev);
2525 ctx->cdev = cdev;
2526
2527 INIT_WORK(&ctx->work, lineinfo_changed_func);
2528 queue_work(ctx->gdev->line_state_wq, &ctx->work);
2529
2530 return NOTIFY_OK;
2531 }
2532
gpio_device_unregistered_notify(struct notifier_block * nb,unsigned long action,void * data)2533 static int gpio_device_unregistered_notify(struct notifier_block *nb,
2534 unsigned long action, void *data)
2535 {
2536 struct gpio_chardev_data *cdev = container_of(nb,
2537 struct gpio_chardev_data,
2538 device_unregistered_nb);
2539
2540 wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);
2541
2542 return NOTIFY_OK;
2543 }
2544
lineinfo_watch_poll(struct file * file,struct poll_table_struct * pollt)2545 static __poll_t lineinfo_watch_poll(struct file *file,
2546 struct poll_table_struct *pollt)
2547 {
2548 struct gpio_chardev_data *cdev = file->private_data;
2549 __poll_t events = 0;
2550
2551 guard(srcu)(&cdev->gdev->srcu);
2552
2553 if (!rcu_access_pointer(cdev->gdev->chip))
2554 return EPOLLHUP | EPOLLERR;
2555
2556 poll_wait(file, &cdev->wait, pollt);
2557
2558 if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
2559 &cdev->wait.lock))
2560 events = EPOLLIN | EPOLLRDNORM;
2561
2562 return events;
2563 }
2564
lineinfo_watch_read(struct file * file,char __user * buf,size_t count,loff_t * off)2565 static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
2566 size_t count, loff_t *off)
2567 {
2568 struct gpio_chardev_data *cdev = file->private_data;
2569 struct gpio_v2_line_info_changed event;
2570 ssize_t bytes_read = 0;
2571 int ret;
2572 size_t event_size;
2573
2574 guard(srcu)(&cdev->gdev->srcu);
2575
2576 if (!rcu_access_pointer(cdev->gdev->chip))
2577 return -ENODEV;
2578
2579 #ifndef CONFIG_GPIO_CDEV_V1
2580 event_size = sizeof(struct gpio_v2_line_info_changed);
2581 if (count < event_size)
2582 return -EINVAL;
2583 #endif
2584
2585 do {
2586 scoped_guard(spinlock, &cdev->wait.lock) {
2587 if (kfifo_is_empty(&cdev->events)) {
2588 if (bytes_read)
2589 return bytes_read;
2590
2591 if (file->f_flags & O_NONBLOCK)
2592 return -EAGAIN;
2593
2594 ret = wait_event_interruptible_locked(cdev->wait,
2595 !kfifo_is_empty(&cdev->events));
2596 if (ret)
2597 return ret;
2598 }
2599 #ifdef CONFIG_GPIO_CDEV_V1
2600 /* must be after kfifo check so watch_abi_version is set */
2601 if (atomic_read(&cdev->watch_abi_version) == 2)
2602 event_size = sizeof(struct gpio_v2_line_info_changed);
2603 else
2604 event_size = sizeof(struct gpioline_info_changed);
2605 if (count < event_size)
2606 return -EINVAL;
2607 #endif
2608 if (kfifo_out(&cdev->events, &event, 1) != 1) {
2609 /*
2610 * This should never happen - we hold the
2611 * lock from the moment we learned the fifo
2612 * is no longer empty until now.
2613 */
2614 WARN(1, "failed to read from non-empty kfifo");
2615 return -EIO;
2616 }
2617 }
2618
2619 #ifdef CONFIG_GPIO_CDEV_V1
2620 if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
2621 if (copy_to_user(buf + bytes_read, &event, event_size))
2622 return -EFAULT;
2623 } else {
2624 struct gpioline_info_changed event_v1;
2625
2626 gpio_v2_line_info_changed_to_v1(&event, &event_v1);
2627 if (copy_to_user(buf + bytes_read, &event_v1,
2628 event_size))
2629 return -EFAULT;
2630 }
2631 #else
2632 if (copy_to_user(buf + bytes_read, &event, event_size))
2633 return -EFAULT;
2634 #endif
2635 bytes_read += event_size;
2636 } while (count >= bytes_read + sizeof(event));
2637
2638 return bytes_read;
2639 }
2640
2641 /**
2642 * gpio_chrdev_open() - open the chardev for ioctl operations
2643 * @inode: inode for this chardev
2644 * @file: file struct for storing private data
2645 *
2646 * Returns:
2647 * 0 on success, or negative errno on failure.
2648 */
gpio_chrdev_open(struct inode * inode,struct file * file)2649 static int gpio_chrdev_open(struct inode *inode, struct file *file)
2650 {
2651 struct gpio_device *gdev = container_of(inode->i_cdev,
2652 struct gpio_device, chrdev);
2653 struct gpio_chardev_data *cdev;
2654 int ret = -ENOMEM;
2655
2656 cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
2657 if (!cdev)
2658 return -ENOMEM;
2659
2660 cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
2661 if (!cdev->watched_lines)
2662 goto out_free_cdev;
2663
2664 init_waitqueue_head(&cdev->wait);
2665 INIT_KFIFO(cdev->events);
2666 cdev->gdev = gpio_device_get(gdev);
2667
2668 cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
2669 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2670 ret = raw_notifier_chain_register(&gdev->line_state_notifier,
2671 &cdev->lineinfo_changed_nb);
2672 if (ret)
2673 goto out_free_bitmap;
2674
2675 cdev->device_unregistered_nb.notifier_call =
2676 gpio_device_unregistered_notify;
2677 ret = blocking_notifier_chain_register(&gdev->device_notifier,
2678 &cdev->device_unregistered_nb);
2679 if (ret)
2680 goto out_unregister_line_notifier;
2681
2682 file->private_data = cdev;
2683 cdev->fp = file;
2684
2685 ret = nonseekable_open(inode, file);
2686 if (ret)
2687 goto out_unregister_device_notifier;
2688
2689 return ret;
2690
2691 out_unregister_device_notifier:
2692 blocking_notifier_chain_unregister(&gdev->device_notifier,
2693 &cdev->device_unregistered_nb);
2694 out_unregister_line_notifier:
2695 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2696 raw_notifier_chain_unregister(&gdev->line_state_notifier,
2697 &cdev->lineinfo_changed_nb);
2698 out_free_bitmap:
2699 gpio_device_put(gdev);
2700 bitmap_free(cdev->watched_lines);
2701 out_free_cdev:
2702 kfree(cdev);
2703 return ret;
2704 }
2705
2706 /**
2707 * gpio_chrdev_release() - close chardev after ioctl operations
2708 * @inode: inode for this chardev
2709 * @file: file struct for storing private data
2710 *
2711 * Returns:
2712 * 0 on success, or negative errno on failure.
2713 */
gpio_chrdev_release(struct inode * inode,struct file * file)2714 static int gpio_chrdev_release(struct inode *inode, struct file *file)
2715 {
2716 struct gpio_chardev_data *cdev = file->private_data;
2717 struct gpio_device *gdev = cdev->gdev;
2718
2719 blocking_notifier_chain_unregister(&gdev->device_notifier,
2720 &cdev->device_unregistered_nb);
2721 scoped_guard(write_lock_irqsave, &gdev->line_state_lock)
2722 raw_notifier_chain_unregister(&gdev->line_state_notifier,
2723 &cdev->lineinfo_changed_nb);
2724 bitmap_free(cdev->watched_lines);
2725 gpio_device_put(gdev);
2726 kfree(cdev);
2727
2728 return 0;
2729 }
2730
2731 static const struct file_operations gpio_fileops = {
2732 .release = gpio_chrdev_release,
2733 .open = gpio_chrdev_open,
2734 .poll = lineinfo_watch_poll,
2735 .read = lineinfo_watch_read,
2736 .owner = THIS_MODULE,
2737 .unlocked_ioctl = gpio_ioctl,
2738 #ifdef CONFIG_COMPAT
2739 .compat_ioctl = gpio_ioctl_compat,
2740 #endif
2741 };
2742
gpiolib_cdev_register(struct gpio_chip * gc,dev_t devt)2743 int gpiolib_cdev_register(struct gpio_chip *gc, dev_t devt)
2744 {
2745 struct gpio_device *gdev = gc->gpiodev;
2746 int ret;
2747
2748 cdev_init(&gdev->chrdev, &gpio_fileops);
2749 gdev->chrdev.owner = THIS_MODULE;
2750 gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
2751
2752 gdev->line_state_wq = alloc_ordered_workqueue("%s", WQ_HIGHPRI,
2753 dev_name(&gdev->dev));
2754 if (!gdev->line_state_wq)
2755 return -ENOMEM;
2756
2757 ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
2758 if (ret) {
2759 destroy_workqueue(gdev->line_state_wq);
2760 return ret;
2761 }
2762
2763 gpiochip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);
2764
2765 return 0;
2766 }
2767
gpiolib_cdev_unregister(struct gpio_device * gdev)2768 void gpiolib_cdev_unregister(struct gpio_device *gdev)
2769 {
2770 destroy_workqueue(gdev->line_state_wq);
2771 cdev_device_del(&gdev->chrdev, &gdev->dev);
2772 blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
2773 }
2774