xref: /linux/drivers/tty/serdev/core.c (revision 30f1d370744cc35f26d78a1dd31aeb0e4be93c38) 
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 void serdev_device_write_wakeup(struct serdev_device *serdev)
136 {
137 	complete(&serdev->write_comp);
138 }
139 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
140 
141 int serdev_device_write_buf(struct serdev_device *serdev,
142 			    const unsigned char *buf, size_t count)
143 {
144 	struct serdev_controller *ctrl = serdev->ctrl;
145 
146 	if (!ctrl || !ctrl->ops->write_buf)
147 		return -EINVAL;
148 
149 	return ctrl->ops->write_buf(ctrl, buf, count);
150 }
151 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
152 
153 int serdev_device_write(struct serdev_device *serdev,
154 			const unsigned char *buf, size_t count,
155 			unsigned long timeout)
156 {
157 	struct serdev_controller *ctrl = serdev->ctrl;
158 	int ret;
159 
160 	if (!ctrl || !ctrl->ops->write_buf ||
161 	    (timeout && !serdev->ops->write_wakeup))
162 		return -EINVAL;
163 
164 	mutex_lock(&serdev->write_lock);
165 	do {
166 		reinit_completion(&serdev->write_comp);
167 
168 		ret = ctrl->ops->write_buf(ctrl, buf, count);
169 		if (ret < 0)
170 			break;
171 
172 		buf += ret;
173 		count -= ret;
174 
175 	} while (count &&
176 		 (timeout = wait_for_completion_timeout(&serdev->write_comp,
177 							timeout)));
178 	mutex_unlock(&serdev->write_lock);
179 	return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
180 }
181 EXPORT_SYMBOL_GPL(serdev_device_write);
182 
183 void serdev_device_write_flush(struct serdev_device *serdev)
184 {
185 	struct serdev_controller *ctrl = serdev->ctrl;
186 
187 	if (!ctrl || !ctrl->ops->write_flush)
188 		return;
189 
190 	ctrl->ops->write_flush(ctrl);
191 }
192 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
193 
194 int serdev_device_write_room(struct serdev_device *serdev)
195 {
196 	struct serdev_controller *ctrl = serdev->ctrl;
197 
198 	if (!ctrl || !ctrl->ops->write_room)
199 		return 0;
200 
201 	return serdev->ctrl->ops->write_room(ctrl);
202 }
203 EXPORT_SYMBOL_GPL(serdev_device_write_room);
204 
205 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
206 {
207 	struct serdev_controller *ctrl = serdev->ctrl;
208 
209 	if (!ctrl || !ctrl->ops->set_baudrate)
210 		return 0;
211 
212 	return ctrl->ops->set_baudrate(ctrl, speed);
213 
214 }
215 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
216 
217 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
218 {
219 	struct serdev_controller *ctrl = serdev->ctrl;
220 
221 	if (!ctrl || !ctrl->ops->set_flow_control)
222 		return;
223 
224 	ctrl->ops->set_flow_control(ctrl, enable);
225 }
226 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
227 
228 int serdev_device_set_parity(struct serdev_device *serdev,
229 			     enum serdev_parity parity)
230 {
231 	struct serdev_controller *ctrl = serdev->ctrl;
232 
233 	if (!ctrl || !ctrl->ops->set_parity)
234 		return -ENOTSUPP;
235 
236 	return ctrl->ops->set_parity(ctrl, parity);
237 }
238 EXPORT_SYMBOL_GPL(serdev_device_set_parity);
239 
240 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
241 {
242 	struct serdev_controller *ctrl = serdev->ctrl;
243 
244 	if (!ctrl || !ctrl->ops->wait_until_sent)
245 		return;
246 
247 	ctrl->ops->wait_until_sent(ctrl, timeout);
248 }
249 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
250 
251 int serdev_device_get_tiocm(struct serdev_device *serdev)
252 {
253 	struct serdev_controller *ctrl = serdev->ctrl;
254 
255 	if (!ctrl || !ctrl->ops->get_tiocm)
256 		return -ENOTSUPP;
257 
258 	return ctrl->ops->get_tiocm(ctrl);
259 }
260 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
261 
262 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
263 {
264 	struct serdev_controller *ctrl = serdev->ctrl;
265 
266 	if (!ctrl || !ctrl->ops->set_tiocm)
267 		return -ENOTSUPP;
268 
269 	return ctrl->ops->set_tiocm(ctrl, set, clear);
270 }
271 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
272 
273 static int serdev_drv_probe(struct device *dev)
274 {
275 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
276 
277 	return sdrv->probe(to_serdev_device(dev));
278 }
279 
280 static int serdev_drv_remove(struct device *dev)
281 {
282 	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
283 
284 	sdrv->remove(to_serdev_device(dev));
285 	return 0;
286 }
287 
288 static ssize_t modalias_show(struct device *dev,
289 			     struct device_attribute *attr, char *buf)
290 {
291 	int len;
292 
293 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
294 	if (len != -ENODEV)
295 		return len;
296 
297 	return of_device_modalias(dev, buf, PAGE_SIZE);
298 }
299 DEVICE_ATTR_RO(modalias);
300 
301 static struct attribute *serdev_device_attrs[] = {
302 	&dev_attr_modalias.attr,
303 	NULL,
304 };
305 ATTRIBUTE_GROUPS(serdev_device);
306 
307 static struct bus_type serdev_bus_type = {
308 	.name		= "serial",
309 	.match		= serdev_device_match,
310 	.probe		= serdev_drv_probe,
311 	.remove		= serdev_drv_remove,
312 	.uevent		= serdev_uevent,
313 	.dev_groups	= serdev_device_groups,
314 };
315 
316 /**
317  * serdev_controller_alloc() - Allocate a new serdev device
318  * @ctrl:	associated controller
319  *
320  * Caller is responsible for either calling serdev_device_add() to add the
321  * newly allocated controller, or calling serdev_device_put() to discard it.
322  */
323 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
324 {
325 	struct serdev_device *serdev;
326 
327 	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
328 	if (!serdev)
329 		return NULL;
330 
331 	serdev->ctrl = ctrl;
332 	device_initialize(&serdev->dev);
333 	serdev->dev.parent = &ctrl->dev;
334 	serdev->dev.bus = &serdev_bus_type;
335 	serdev->dev.type = &serdev_device_type;
336 	init_completion(&serdev->write_comp);
337 	mutex_init(&serdev->write_lock);
338 	return serdev;
339 }
340 EXPORT_SYMBOL_GPL(serdev_device_alloc);
341 
342 /**
343  * serdev_controller_alloc() - Allocate a new serdev controller
344  * @parent:	parent device
345  * @size:	size of private data
346  *
347  * Caller is responsible for either calling serdev_controller_add() to add the
348  * newly allocated controller, or calling serdev_controller_put() to discard it.
349  * The allocated private data region may be accessed via
350  * serdev_controller_get_drvdata()
351  */
352 struct serdev_controller *serdev_controller_alloc(struct device *parent,
353 					      size_t size)
354 {
355 	struct serdev_controller *ctrl;
356 	int id;
357 
358 	if (WARN_ON(!parent))
359 		return NULL;
360 
361 	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
362 	if (!ctrl)
363 		return NULL;
364 
365 	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
366 	if (id < 0) {
367 		dev_err(parent,
368 			"unable to allocate serdev controller identifier.\n");
369 		goto err_free;
370 	}
371 
372 	ctrl->nr = id;
373 
374 	device_initialize(&ctrl->dev);
375 	ctrl->dev.type = &serdev_ctrl_type;
376 	ctrl->dev.bus = &serdev_bus_type;
377 	ctrl->dev.parent = parent;
378 	ctrl->dev.of_node = parent->of_node;
379 	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
380 
381 	dev_set_name(&ctrl->dev, "serial%d", id);
382 
383 	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
384 	return ctrl;
385 
386 err_free:
387 	kfree(ctrl);
388 
389 	return NULL;
390 }
391 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
392 
393 static int of_serdev_register_devices(struct serdev_controller *ctrl)
394 {
395 	struct device_node *node;
396 	struct serdev_device *serdev = NULL;
397 	int err;
398 	bool found = false;
399 
400 	for_each_available_child_of_node(ctrl->dev.of_node, node) {
401 		if (!of_get_property(node, "compatible", NULL))
402 			continue;
403 
404 		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
405 
406 		serdev = serdev_device_alloc(ctrl);
407 		if (!serdev)
408 			continue;
409 
410 		serdev->dev.of_node = node;
411 
412 		err = serdev_device_add(serdev);
413 		if (err) {
414 			dev_err(&serdev->dev,
415 				"failure adding device. status %d\n", err);
416 			serdev_device_put(serdev);
417 		} else
418 			found = true;
419 	}
420 	if (!found)
421 		return -ENODEV;
422 
423 	return 0;
424 }
425 
426 #ifdef CONFIG_ACPI
427 static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
428 					    struct acpi_device *adev)
429 {
430 	struct serdev_device *serdev = NULL;
431 	int err;
432 
433 	if (acpi_bus_get_status(adev) || !adev->status.present ||
434 	    acpi_device_enumerated(adev))
435 		return AE_OK;
436 
437 	serdev = serdev_device_alloc(ctrl);
438 	if (!serdev) {
439 		dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
440 			dev_name(&adev->dev));
441 		return AE_NO_MEMORY;
442 	}
443 
444 	ACPI_COMPANION_SET(&serdev->dev, adev);
445 	acpi_device_set_enumerated(adev);
446 
447 	err = serdev_device_add(serdev);
448 	if (err) {
449 		dev_err(&serdev->dev,
450 			"failure adding ACPI serdev device. status %d\n", err);
451 		serdev_device_put(serdev);
452 	}
453 
454 	return AE_OK;
455 }
456 
457 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
458 				       void *data, void **return_value)
459 {
460 	struct serdev_controller *ctrl = data;
461 	struct acpi_device *adev;
462 
463 	if (acpi_bus_get_device(handle, &adev))
464 		return AE_OK;
465 
466 	return acpi_serdev_register_device(ctrl, adev);
467 }
468 
469 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
470 {
471 	acpi_status status;
472 	acpi_handle handle;
473 
474 	handle = ACPI_HANDLE(ctrl->dev.parent);
475 	if (!handle)
476 		return -ENODEV;
477 
478 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
479 				     acpi_serdev_add_device, NULL, ctrl, NULL);
480 	if (ACPI_FAILURE(status))
481 		dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
482 
483 	if (!ctrl->serdev)
484 		return -ENODEV;
485 
486 	return 0;
487 }
488 #else
489 static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
490 {
491 	return -ENODEV;
492 }
493 #endif /* CONFIG_ACPI */
494 
495 /**
496  * serdev_controller_add() - Add an serdev controller
497  * @ctrl:	controller to be registered.
498  *
499  * Register a controller previously allocated via serdev_controller_alloc() with
500  * the serdev core.
501  */
502 int serdev_controller_add(struct serdev_controller *ctrl)
503 {
504 	int ret_of, ret_acpi, ret;
505 
506 	/* Can't register until after driver model init */
507 	if (WARN_ON(!is_registered))
508 		return -EAGAIN;
509 
510 	ret = device_add(&ctrl->dev);
511 	if (ret)
512 		return ret;
513 
514 	ret_of = of_serdev_register_devices(ctrl);
515 	ret_acpi = acpi_serdev_register_devices(ctrl);
516 	if (ret_of && ret_acpi) {
517 		dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d\n",
518 			ret_of, ret_acpi);
519 		ret = -ENODEV;
520 		goto out_dev_del;
521 	}
522 
523 	dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
524 		ctrl->nr, &ctrl->dev);
525 	return 0;
526 
527 out_dev_del:
528 	device_del(&ctrl->dev);
529 	return ret;
530 };
531 EXPORT_SYMBOL_GPL(serdev_controller_add);
532 
533 /* Remove a device associated with a controller */
534 static int serdev_remove_device(struct device *dev, void *data)
535 {
536 	struct serdev_device *serdev = to_serdev_device(dev);
537 	if (dev->type == &serdev_device_type)
538 		serdev_device_remove(serdev);
539 	return 0;
540 }
541 
542 /**
543  * serdev_controller_remove(): remove an serdev controller
544  * @ctrl:	controller to remove
545  *
546  * Remove a serdev controller.  Caller is responsible for calling
547  * serdev_controller_put() to discard the allocated controller.
548  */
549 void serdev_controller_remove(struct serdev_controller *ctrl)
550 {
551 	int dummy;
552 
553 	if (!ctrl)
554 		return;
555 
556 	dummy = device_for_each_child(&ctrl->dev, NULL,
557 				      serdev_remove_device);
558 	device_del(&ctrl->dev);
559 }
560 EXPORT_SYMBOL_GPL(serdev_controller_remove);
561 
562 /**
563  * serdev_driver_register() - Register client driver with serdev core
564  * @sdrv:	client driver to be associated with client-device.
565  *
566  * This API will register the client driver with the serdev framework.
567  * It is typically called from the driver's module-init function.
568  */
569 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
570 {
571 	sdrv->driver.bus = &serdev_bus_type;
572 	sdrv->driver.owner = owner;
573 
574 	/* force drivers to async probe so I/O is possible in probe */
575         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
576 
577 	return driver_register(&sdrv->driver);
578 }
579 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
580 
581 static void __exit serdev_exit(void)
582 {
583 	bus_unregister(&serdev_bus_type);
584 }
585 module_exit(serdev_exit);
586 
587 static int __init serdev_init(void)
588 {
589 	int ret;
590 
591 	ret = bus_register(&serdev_bus_type);
592 	if (ret)
593 		return ret;
594 
595 	is_registered = true;
596 	return 0;
597 }
598 /* Must be before serial drivers register */
599 postcore_initcall(serdev_init);
600 
601 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
602 MODULE_LICENSE("GPL v2");
603 MODULE_DESCRIPTION("Serial attached device bus");
604