xref: /linux/drivers/tty/serdev/core.c (revision 667ca1ec7c9eb7ac3b80590b6597151b4c2a750b) 
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 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
256 {
257 	struct serdev_controller *ctrl = serdev->ctrl;
258 
259 	if (!ctrl || !ctrl->ops->wait_until_sent)
260 		return;
261 
262 	ctrl->ops->wait_until_sent(ctrl, timeout);
263 }
264 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
265 
266 int serdev_device_get_tiocm(struct serdev_device *serdev)
267 {
268 	struct serdev_controller *ctrl = serdev->ctrl;
269 
270 	if (!ctrl || !ctrl->ops->get_tiocm)
271 		return -ENOTSUPP;
272 
273 	return ctrl->ops->get_tiocm(ctrl);
274 }
275 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
276 
277 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
278 {
279 	struct serdev_controller *ctrl = serdev->ctrl;
280 
281 	if (!ctrl || !ctrl->ops->set_tiocm)
282 		return -ENOTSUPP;
283 
284 	return ctrl->ops->set_tiocm(ctrl, set, clear);
285 }
286 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
287 
288 static int serdev_drv_probe(struct device *dev)
289 {
290 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
291 
292 	return sdrv->probe(to_serdev_device(dev));
293 }
294 
295 static int serdev_drv_remove(struct device *dev)
296 {
297 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
298 	if (sdrv->remove)
299 		sdrv->remove(to_serdev_device(dev));
300 	return 0;
301 }
302 
303 static ssize_t modalias_show(struct device *dev,
304 			     struct device_attribute *attr, char *buf)
305 {
306 	int len;
307 
308 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
309 	if (len != -ENODEV)
310 		return len;
311 
312 	return of_device_modalias(dev, buf, PAGE_SIZE);
313 }
314 DEVICE_ATTR_RO(modalias);
315 
316 static struct attribute *serdev_device_attrs[] = {
317 	&dev_attr_modalias.attr,
318 	NULL,
319 };
320 ATTRIBUTE_GROUPS(serdev_device);
321 
322 static struct bus_type serdev_bus_type = {
323 	.name		= "serial",
324 	.match		= serdev_device_match,
325 	.probe		= serdev_drv_probe,
326 	.remove		= serdev_drv_remove,
327 	.uevent		= serdev_uevent,
328 	.dev_groups	= serdev_device_groups,
329 };
330 
331 /**
332  * serdev_controller_alloc() - Allocate a new serdev device
333  * @ctrl:	associated controller
334  *
335  * Caller is responsible for either calling serdev_device_add() to add the
336  * newly allocated controller, or calling serdev_device_put() to discard it.
337  */
338 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
339 {
340 	struct serdev_device *serdev;
341 
342 	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
343 	if (!serdev)
344 		return NULL;
345 
346 	serdev->ctrl = ctrl;
347 	device_initialize(&serdev->dev);
348 	serdev->dev.parent = &ctrl->dev;
349 	serdev->dev.bus = &serdev_bus_type;
350 	serdev->dev.type = &serdev_device_type;
351 	init_completion(&serdev->write_comp);
352 	mutex_init(&serdev->write_lock);
353 	return serdev;
354 }
355 EXPORT_SYMBOL_GPL(serdev_device_alloc);
356 
357 /**
358  * serdev_controller_alloc() - Allocate a new serdev controller
359  * @parent:	parent device
360  * @size:	size of private data
361  *
362  * Caller is responsible for either calling serdev_controller_add() to add the
363  * newly allocated controller, or calling serdev_controller_put() to discard it.
364  * The allocated private data region may be accessed via
365  * serdev_controller_get_drvdata()
366  */
367 struct serdev_controller *serdev_controller_alloc(struct device *parent,
368 					      size_t size)
369 {
370 	struct serdev_controller *ctrl;
371 	int id;
372 
373 	if (WARN_ON(!parent))
374 		return NULL;
375 
376 	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
377 	if (!ctrl)
378 		return NULL;
379 
380 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
381 	if (id < 0) {
382 		dev_err(parent,
383 			"unable to allocate serdev controller identifier.\n");
384 		goto err_free;
385 	}
386 
387 	ctrl->nr = id;
388 
389 	device_initialize(&ctrl->dev);
390 	ctrl->dev.type = &serdev_ctrl_type;
391 	ctrl->dev.bus = &serdev_bus_type;
392 	ctrl->dev.parent = parent;
393 	ctrl->dev.of_node = parent->of_node;
394 	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
395 
396 	dev_set_name(&ctrl->dev, "serial%d", id);
397 
398 	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
399 	return ctrl;
400 
401 err_free:
402 	kfree(ctrl);
403 
404 	return NULL;
405 }
406 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
407 
408 static int of_serdev_register_devices(struct serdev_controller *ctrl)
409 {
410 	struct device_node *node;
411 	struct serdev_device *serdev = NULL;
412 	int err;
413 	bool found = false;
414 
415 	for_each_available_child_of_node(ctrl->dev.of_node, node) {
416 		if (!of_get_property(node, "compatible", NULL))
417 			continue;
418 
419 		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
420 
421 		serdev = serdev_device_alloc(ctrl);
422 		if (!serdev)
423 			continue;
424 
425 		serdev->dev.of_node = node;
426 
427 		err = serdev_device_add(serdev);
428 		if (err) {
429 			dev_err(&serdev->dev,
430 				"failure adding device. status %d\n", err);
431 			serdev_device_put(serdev);
432 		} else
433 			found = true;
434 	}
435 	if (!found)
436 		return -ENODEV;
437 
438 	return 0;
439 }
440 
441 #ifdef CONFIG_ACPI
442 static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
443 					    struct acpi_device *adev)
444 {
445 	struct serdev_device *serdev = NULL;
446 	int err;
447 
448 	if (acpi_bus_get_status(adev) || !adev->status.present ||
449 	    acpi_device_enumerated(adev))
450 		return AE_OK;
451 
452 	serdev = serdev_device_alloc(ctrl);
453 	if (!serdev) {
454 		dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
455 			dev_name(&adev->dev));
456 		return AE_NO_MEMORY;
457 	}
458 
459 	ACPI_COMPANION_SET(&serdev->dev, adev);
460 	acpi_device_set_enumerated(adev);
461 
462 	err = serdev_device_add(serdev);
463 	if (err) {
464 		dev_err(&serdev->dev,
465 			"failure adding ACPI serdev device. status %d\n", err);
466 		serdev_device_put(serdev);
467 	}
468 
469 	return AE_OK;
470 }
471 
472 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
473 				       void *data, void **return_value)
474 {
475 	struct serdev_controller *ctrl = data;
476 	struct acpi_device *adev;
477 
478 	if (acpi_bus_get_device(handle, &adev))
479 		return AE_OK;
480 
481 	return acpi_serdev_register_device(ctrl, adev);
482 }
483 
484 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
485 {
486 	acpi_status status;
487 	acpi_handle handle;
488 
489 	handle = ACPI_HANDLE(ctrl->dev.parent);
490 	if (!handle)
491 		return -ENODEV;
492 
493 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
494 				     acpi_serdev_add_device, NULL, ctrl, NULL);
495 	if (ACPI_FAILURE(status))
496 		dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
497 
498 	if (!ctrl->serdev)
499 		return -ENODEV;
500 
501 	return 0;
502 }
503 #else
504 static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
505 {
506 	return -ENODEV;
507 }
508 #endif /* CONFIG_ACPI */
509 
510 /**
511  * serdev_controller_add() - Add an serdev controller
512  * @ctrl:	controller to be registered.
513  *
514  * Register a controller previously allocated via serdev_controller_alloc() with
515  * the serdev core.
516  */
517 int serdev_controller_add(struct serdev_controller *ctrl)
518 {
519 	int ret_of, ret_acpi, ret;
520 
521 	/* Can't register until after driver model init */
522 	if (WARN_ON(!is_registered))
523 		return -EAGAIN;
524 
525 	ret = device_add(&ctrl->dev);
526 	if (ret)
527 		return ret;
528 
529 	ret_of = of_serdev_register_devices(ctrl);
530 	ret_acpi = acpi_serdev_register_devices(ctrl);
531 	if (ret_of && ret_acpi) {
532 		dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d\n",
533 			ret_of, ret_acpi);
534 		ret = -ENODEV;
535 		goto out_dev_del;
536 	}
537 
538 	dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
539 		ctrl->nr, &ctrl->dev);
540 	return 0;
541 
542 out_dev_del:
543 	device_del(&ctrl->dev);
544 	return ret;
545 };
546 EXPORT_SYMBOL_GPL(serdev_controller_add);
547 
548 /* Remove a device associated with a controller */
549 static int serdev_remove_device(struct device *dev, void *data)
550 {
551 	struct serdev_device *serdev = to_serdev_device(dev);
552 	if (dev->type == &serdev_device_type)
553 		serdev_device_remove(serdev);
554 	return 0;
555 }
556 
557 /**
558  * serdev_controller_remove(): remove an serdev controller
559  * @ctrl:	controller to remove
560  *
561  * Remove a serdev controller.  Caller is responsible for calling
562  * serdev_controller_put() to discard the allocated controller.
563  */
564 void serdev_controller_remove(struct serdev_controller *ctrl)
565 {
566 	int dummy;
567 
568 	if (!ctrl)
569 		return;
570 
571 	dummy = device_for_each_child(&ctrl->dev, NULL,
572 				      serdev_remove_device);
573 	device_del(&ctrl->dev);
574 }
575 EXPORT_SYMBOL_GPL(serdev_controller_remove);
576 
577 /**
578  * serdev_driver_register() - Register client driver with serdev core
579  * @sdrv:	client driver to be associated with client-device.
580  *
581  * This API will register the client driver with the serdev framework.
582  * It is typically called from the driver's module-init function.
583  */
584 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
585 {
586 	sdrv->driver.bus = &serdev_bus_type;
587 	sdrv->driver.owner = owner;
588 
589 	/* force drivers to async probe so I/O is possible in probe */
590         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
591 
592 	return driver_register(&sdrv->driver);
593 }
594 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
595 
596 static void __exit serdev_exit(void)
597 {
598 	bus_unregister(&serdev_bus_type);
599 }
600 module_exit(serdev_exit);
601 
602 static int __init serdev_init(void)
603 {
604 	int ret;
605 
606 	ret = bus_register(&serdev_bus_type);
607 	if (ret)
608 		return ret;
609 
610 	is_registered = true;
611 	return 0;
612 }
613 /* Must be before serial drivers register */
614 postcore_initcall(serdev_init);
615 
616 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
617 MODULE_LICENSE("GPL v2");
618 MODULE_DESCRIPTION("Serial attached device bus");
619