xref: /linux/drivers/tty/serdev/core.c (revision 255442c93843f52b6891b21d0b485bf2c97f93c3) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
4  *
5  * Based on drivers/spmi/spmi.c:
6  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
7  */
8 
9 #include <linux/acpi.h>
10 #include <linux/errno.h>
11 #include <linux/idr.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/serdev.h>
17 #include <linux/slab.h>
18 
19 static bool is_registered;
20 static DEFINE_IDA(ctrl_ida);
21 
22 static void serdev_device_release(struct device *dev)
23 {
24 	struct serdev_device *serdev = to_serdev_device(dev);
25 	kfree(serdev);
26 }
27 
28 static const struct device_type serdev_device_type = {
29 	.release	= serdev_device_release,
30 };
31 
32 static void serdev_ctrl_release(struct device *dev)
33 {
34 	struct serdev_controller *ctrl = to_serdev_controller(dev);
35 	ida_simple_remove(&ctrl_ida, ctrl->nr);
36 	kfree(ctrl);
37 }
38 
39 static const struct device_type serdev_ctrl_type = {
40 	.release	= serdev_ctrl_release,
41 };
42 
43 static int serdev_device_match(struct device *dev, struct device_driver *drv)
44 {
45 	/* TODO: platform matching */
46 	if (acpi_driver_match_device(dev, drv))
47 		return 1;
48 
49 	return of_driver_match_device(dev, drv);
50 }
51 
52 static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
53 {
54 	int rc;
55 
56 	/* TODO: platform modalias */
57 	rc = acpi_device_uevent_modalias(dev, env);
58 	if (rc != -ENODEV)
59 		return rc;
60 
61 	return of_device_uevent_modalias(dev, env);
62 }
63 
64 /**
65  * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
66  * @serdev:	serdev_device to be added
67  */
68 int serdev_device_add(struct serdev_device *serdev)
69 {
70 	struct serdev_controller *ctrl = serdev->ctrl;
71 	struct device *parent = serdev->dev.parent;
72 	int err;
73 
74 	dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
75 
76 	/* Only a single slave device is currently supported. */
77 	if (ctrl->serdev) {
78 		dev_err(&serdev->dev, "controller busy\n");
79 		return -EBUSY;
80 	}
81 	ctrl->serdev = serdev;
82 
83 	err = device_add(&serdev->dev);
84 	if (err < 0) {
85 		dev_err(&serdev->dev, "Can't add %s, status %d\n",
86 			dev_name(&serdev->dev), err);
87 		goto err_clear_serdev;
88 	}
89 
90 	dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
91 
92 	return 0;
93 
94 err_clear_serdev:
95 	ctrl->serdev = NULL;
96 	return err;
97 }
98 EXPORT_SYMBOL_GPL(serdev_device_add);
99 
100 /**
101  * serdev_device_remove(): remove an serdev device
102  * @serdev:	serdev_device to be removed
103  */
104 void serdev_device_remove(struct serdev_device *serdev)
105 {
106 	struct serdev_controller *ctrl = serdev->ctrl;
107 
108 	device_unregister(&serdev->dev);
109 	ctrl->serdev = NULL;
110 }
111 EXPORT_SYMBOL_GPL(serdev_device_remove);
112 
113 int serdev_device_open(struct serdev_device *serdev)
114 {
115 	struct serdev_controller *ctrl = serdev->ctrl;
116 
117 	if (!ctrl || !ctrl->ops->open)
118 		return -EINVAL;
119 
120 	return ctrl->ops->open(ctrl);
121 }
122 EXPORT_SYMBOL_GPL(serdev_device_open);
123 
124 void serdev_device_close(struct serdev_device *serdev)
125 {
126 	struct serdev_controller *ctrl = serdev->ctrl;
127 
128 	if (!ctrl || !ctrl->ops->close)
129 		return;
130 
131 	ctrl->ops->close(ctrl);
132 }
133 EXPORT_SYMBOL_GPL(serdev_device_close);
134 
135 static void devm_serdev_device_release(struct device *dev, void *dr)
136 {
137 	serdev_device_close(*(struct serdev_device **)dr);
138 }
139 
140 int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
141 {
142 	struct serdev_device **dr;
143 	int ret;
144 
145 	dr = devres_alloc(devm_serdev_device_release, sizeof(*dr), GFP_KERNEL);
146 	if (!dr)
147 		return -ENOMEM;
148 
149 	ret = serdev_device_open(serdev);
150 	if (ret) {
151 		devres_free(dr);
152 		return ret;
153 	}
154 
155 	*dr = serdev;
156 	devres_add(dev, dr);
157 
158 	return 0;
159 }
160 EXPORT_SYMBOL_GPL(devm_serdev_device_open);
161 
162 void serdev_device_write_wakeup(struct serdev_device *serdev)
163 {
164 	complete(&serdev->write_comp);
165 }
166 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
167 
168 int serdev_device_write_buf(struct serdev_device *serdev,
169 			    const unsigned char *buf, size_t count)
170 {
171 	struct serdev_controller *ctrl = serdev->ctrl;
172 
173 	if (!ctrl || !ctrl->ops->write_buf)
174 		return -EINVAL;
175 
176 	return ctrl->ops->write_buf(ctrl, buf, count);
177 }
178 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
179 
180 int serdev_device_write(struct serdev_device *serdev,
181 			const unsigned char *buf, size_t count,
182 			unsigned long timeout)
183 {
184 	struct serdev_controller *ctrl = serdev->ctrl;
185 	int ret;
186 
187 	if (!ctrl || !ctrl->ops->write_buf ||
188 	    (timeout && !serdev->ops->write_wakeup))
189 		return -EINVAL;
190 
191 	mutex_lock(&serdev->write_lock);
192 	do {
193 		reinit_completion(&serdev->write_comp);
194 
195 		ret = ctrl->ops->write_buf(ctrl, buf, count);
196 		if (ret < 0)
197 			break;
198 
199 		buf += ret;
200 		count -= ret;
201 
202 	} while (count &&
203 		 (timeout = wait_for_completion_timeout(&serdev->write_comp,
204 							timeout)));
205 	mutex_unlock(&serdev->write_lock);
206 	return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
207 }
208 EXPORT_SYMBOL_GPL(serdev_device_write);
209 
210 void serdev_device_write_flush(struct serdev_device *serdev)
211 {
212 	struct serdev_controller *ctrl = serdev->ctrl;
213 
214 	if (!ctrl || !ctrl->ops->write_flush)
215 		return;
216 
217 	ctrl->ops->write_flush(ctrl);
218 }
219 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
220 
221 int serdev_device_write_room(struct serdev_device *serdev)
222 {
223 	struct serdev_controller *ctrl = serdev->ctrl;
224 
225 	if (!ctrl || !ctrl->ops->write_room)
226 		return 0;
227 
228 	return serdev->ctrl->ops->write_room(ctrl);
229 }
230 EXPORT_SYMBOL_GPL(serdev_device_write_room);
231 
232 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
233 {
234 	struct serdev_controller *ctrl = serdev->ctrl;
235 
236 	if (!ctrl || !ctrl->ops->set_baudrate)
237 		return 0;
238 
239 	return ctrl->ops->set_baudrate(ctrl, speed);
240 
241 }
242 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
243 
244 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
245 {
246 	struct serdev_controller *ctrl = serdev->ctrl;
247 
248 	if (!ctrl || !ctrl->ops->set_flow_control)
249 		return;
250 
251 	ctrl->ops->set_flow_control(ctrl, enable);
252 }
253 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
254 
255 int serdev_device_set_parity(struct serdev_device *serdev,
256 			     enum serdev_parity parity)
257 {
258 	struct serdev_controller *ctrl = serdev->ctrl;
259 
260 	if (!ctrl || !ctrl->ops->set_parity)
261 		return -ENOTSUPP;
262 
263 	return ctrl->ops->set_parity(ctrl, parity);
264 }
265 EXPORT_SYMBOL_GPL(serdev_device_set_parity);
266 
267 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
268 {
269 	struct serdev_controller *ctrl = serdev->ctrl;
270 
271 	if (!ctrl || !ctrl->ops->wait_until_sent)
272 		return;
273 
274 	ctrl->ops->wait_until_sent(ctrl, timeout);
275 }
276 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
277 
278 int serdev_device_get_tiocm(struct serdev_device *serdev)
279 {
280 	struct serdev_controller *ctrl = serdev->ctrl;
281 
282 	if (!ctrl || !ctrl->ops->get_tiocm)
283 		return -ENOTSUPP;
284 
285 	return ctrl->ops->get_tiocm(ctrl);
286 }
287 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
288 
289 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
290 {
291 	struct serdev_controller *ctrl = serdev->ctrl;
292 
293 	if (!ctrl || !ctrl->ops->set_tiocm)
294 		return -ENOTSUPP;
295 
296 	return ctrl->ops->set_tiocm(ctrl, set, clear);
297 }
298 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
299 
300 static int serdev_drv_probe(struct device *dev)
301 {
302 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
303 
304 	return sdrv->probe(to_serdev_device(dev));
305 }
306 
307 static int serdev_drv_remove(struct device *dev)
308 {
309 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
310 	if (sdrv->remove)
311 		sdrv->remove(to_serdev_device(dev));
312 	return 0;
313 }
314 
315 static ssize_t modalias_show(struct device *dev,
316 			     struct device_attribute *attr, char *buf)
317 {
318 	int len;
319 
320 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
321 	if (len != -ENODEV)
322 		return len;
323 
324 	return of_device_modalias(dev, buf, PAGE_SIZE);
325 }
326 DEVICE_ATTR_RO(modalias);
327 
328 static struct attribute *serdev_device_attrs[] = {
329 	&dev_attr_modalias.attr,
330 	NULL,
331 };
332 ATTRIBUTE_GROUPS(serdev_device);
333 
334 static struct bus_type serdev_bus_type = {
335 	.name		= "serial",
336 	.match		= serdev_device_match,
337 	.probe		= serdev_drv_probe,
338 	.remove		= serdev_drv_remove,
339 	.uevent		= serdev_uevent,
340 	.dev_groups	= serdev_device_groups,
341 };
342 
343 /**
344  * serdev_controller_alloc() - Allocate a new serdev device
345  * @ctrl:	associated controller
346  *
347  * Caller is responsible for either calling serdev_device_add() to add the
348  * newly allocated controller, or calling serdev_device_put() to discard it.
349  */
350 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
351 {
352 	struct serdev_device *serdev;
353 
354 	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
355 	if (!serdev)
356 		return NULL;
357 
358 	serdev->ctrl = ctrl;
359 	device_initialize(&serdev->dev);
360 	serdev->dev.parent = &ctrl->dev;
361 	serdev->dev.bus = &serdev_bus_type;
362 	serdev->dev.type = &serdev_device_type;
363 	init_completion(&serdev->write_comp);
364 	mutex_init(&serdev->write_lock);
365 	return serdev;
366 }
367 EXPORT_SYMBOL_GPL(serdev_device_alloc);
368 
369 /**
370  * serdev_controller_alloc() - Allocate a new serdev controller
371  * @parent:	parent device
372  * @size:	size of private data
373  *
374  * Caller is responsible for either calling serdev_controller_add() to add the
375  * newly allocated controller, or calling serdev_controller_put() to discard it.
376  * The allocated private data region may be accessed via
377  * serdev_controller_get_drvdata()
378  */
379 struct serdev_controller *serdev_controller_alloc(struct device *parent,
380 					      size_t size)
381 {
382 	struct serdev_controller *ctrl;
383 	int id;
384 
385 	if (WARN_ON(!parent))
386 		return NULL;
387 
388 	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
389 	if (!ctrl)
390 		return NULL;
391 
392 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
393 	if (id < 0) {
394 		dev_err(parent,
395 			"unable to allocate serdev controller identifier.\n");
396 		goto err_free;
397 	}
398 
399 	ctrl->nr = id;
400 
401 	device_initialize(&ctrl->dev);
402 	ctrl->dev.type = &serdev_ctrl_type;
403 	ctrl->dev.bus = &serdev_bus_type;
404 	ctrl->dev.parent = parent;
405 	ctrl->dev.of_node = parent->of_node;
406 	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
407 
408 	dev_set_name(&ctrl->dev, "serial%d", id);
409 
410 	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
411 	return ctrl;
412 
413 err_free:
414 	kfree(ctrl);
415 
416 	return NULL;
417 }
418 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
419 
420 static int of_serdev_register_devices(struct serdev_controller *ctrl)
421 {
422 	struct device_node *node;
423 	struct serdev_device *serdev = NULL;
424 	int err;
425 	bool found = false;
426 
427 	for_each_available_child_of_node(ctrl->dev.of_node, node) {
428 		if (!of_get_property(node, "compatible", NULL))
429 			continue;
430 
431 		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
432 
433 		serdev = serdev_device_alloc(ctrl);
434 		if (!serdev)
435 			continue;
436 
437 		serdev->dev.of_node = node;
438 
439 		err = serdev_device_add(serdev);
440 		if (err) {
441 			dev_err(&serdev->dev,
442 				"failure adding device. status %d\n", err);
443 			serdev_device_put(serdev);
444 		} else
445 			found = true;
446 	}
447 	if (!found)
448 		return -ENODEV;
449 
450 	return 0;
451 }
452 
453 #ifdef CONFIG_ACPI
454 static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
455 					    struct acpi_device *adev)
456 {
457 	struct serdev_device *serdev = NULL;
458 	int err;
459 
460 	if (acpi_bus_get_status(adev) || !adev->status.present ||
461 	    acpi_device_enumerated(adev))
462 		return AE_OK;
463 
464 	serdev = serdev_device_alloc(ctrl);
465 	if (!serdev) {
466 		dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
467 			dev_name(&adev->dev));
468 		return AE_NO_MEMORY;
469 	}
470 
471 	ACPI_COMPANION_SET(&serdev->dev, adev);
472 	acpi_device_set_enumerated(adev);
473 
474 	err = serdev_device_add(serdev);
475 	if (err) {
476 		dev_err(&serdev->dev,
477 			"failure adding ACPI serdev device. status %d\n", err);
478 		serdev_device_put(serdev);
479 	}
480 
481 	return AE_OK;
482 }
483 
484 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
485 				       void *data, void **return_value)
486 {
487 	struct serdev_controller *ctrl = data;
488 	struct acpi_device *adev;
489 
490 	if (acpi_bus_get_device(handle, &adev))
491 		return AE_OK;
492 
493 	return acpi_serdev_register_device(ctrl, adev);
494 }
495 
496 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
497 {
498 	acpi_status status;
499 	acpi_handle handle;
500 
501 	handle = ACPI_HANDLE(ctrl->dev.parent);
502 	if (!handle)
503 		return -ENODEV;
504 
505 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
506 				     acpi_serdev_add_device, NULL, ctrl, NULL);
507 	if (ACPI_FAILURE(status))
508 		dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
509 
510 	if (!ctrl->serdev)
511 		return -ENODEV;
512 
513 	return 0;
514 }
515 #else
516 static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
517 {
518 	return -ENODEV;
519 }
520 #endif /* CONFIG_ACPI */
521 
522 /**
523  * serdev_controller_add() - Add an serdev controller
524  * @ctrl:	controller to be registered.
525  *
526  * Register a controller previously allocated via serdev_controller_alloc() with
527  * the serdev core.
528  */
529 int serdev_controller_add(struct serdev_controller *ctrl)
530 {
531 	int ret_of, ret_acpi, ret;
532 
533 	/* Can't register until after driver model init */
534 	if (WARN_ON(!is_registered))
535 		return -EAGAIN;
536 
537 	ret = device_add(&ctrl->dev);
538 	if (ret)
539 		return ret;
540 
541 	ret_of = of_serdev_register_devices(ctrl);
542 	ret_acpi = acpi_serdev_register_devices(ctrl);
543 	if (ret_of && ret_acpi) {
544 		dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d\n",
545 			ret_of, ret_acpi);
546 		ret = -ENODEV;
547 		goto out_dev_del;
548 	}
549 
550 	dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
551 		ctrl->nr, &ctrl->dev);
552 	return 0;
553 
554 out_dev_del:
555 	device_del(&ctrl->dev);
556 	return ret;
557 };
558 EXPORT_SYMBOL_GPL(serdev_controller_add);
559 
560 /* Remove a device associated with a controller */
561 static int serdev_remove_device(struct device *dev, void *data)
562 {
563 	struct serdev_device *serdev = to_serdev_device(dev);
564 	if (dev->type == &serdev_device_type)
565 		serdev_device_remove(serdev);
566 	return 0;
567 }
568 
569 /**
570  * serdev_controller_remove(): remove an serdev controller
571  * @ctrl:	controller to remove
572  *
573  * Remove a serdev controller.  Caller is responsible for calling
574  * serdev_controller_put() to discard the allocated controller.
575  */
576 void serdev_controller_remove(struct serdev_controller *ctrl)
577 {
578 	int dummy;
579 
580 	if (!ctrl)
581 		return;
582 
583 	dummy = device_for_each_child(&ctrl->dev, NULL,
584 				      serdev_remove_device);
585 	device_del(&ctrl->dev);
586 }
587 EXPORT_SYMBOL_GPL(serdev_controller_remove);
588 
589 /**
590  * serdev_driver_register() - Register client driver with serdev core
591  * @sdrv:	client driver to be associated with client-device.
592  *
593  * This API will register the client driver with the serdev framework.
594  * It is typically called from the driver's module-init function.
595  */
596 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
597 {
598 	sdrv->driver.bus = &serdev_bus_type;
599 	sdrv->driver.owner = owner;
600 
601 	/* force drivers to async probe so I/O is possible in probe */
602         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
603 
604 	return driver_register(&sdrv->driver);
605 }
606 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
607 
608 static void __exit serdev_exit(void)
609 {
610 	bus_unregister(&serdev_bus_type);
611 }
612 module_exit(serdev_exit);
613 
614 static int __init serdev_init(void)
615 {
616 	int ret;
617 
618 	ret = bus_register(&serdev_bus_type);
619 	if (ret)
620 		return ret;
621 
622 	is_registered = true;
623 	return 0;
624 }
625 /* Must be before serial drivers register */
626 postcore_initcall(serdev_init);
627 
628 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
629 MODULE_LICENSE("GPL v2");
630 MODULE_DESCRIPTION("Serial attached device bus");
631