Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * remote processor messaging bus
4 *
5 * Copyright (C) 2011 Texas Instruments, Inc.
6 * Copyright (C) 2011 Google, Inc.
7 *
8 * Ohad Ben-Cohen <ohad@wizery.com>
9 * Brian Swetland <swetland@google.com>
10 */
11
12#define pr_fmt(fmt) "%s: " fmt, __func__
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/rpmsg.h>
17#include <linux/of_device.h>
18#include <linux/pm_domain.h>
19#include <linux/slab.h>
20
21#include "rpmsg_internal.h"
22
23const struct class rpmsg_class = {
24 .name = "rpmsg",
25};
26EXPORT_SYMBOL(rpmsg_class);
27
28/**
29 * rpmsg_create_channel() - create a new rpmsg channel
30 * using its name and address info.
31 * @rpdev: rpmsg device
32 * @chinfo: channel_info to bind
33 *
34 * Return: a pointer to the new rpmsg device on success, or NULL on error.
35 */
36struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev,
37 struct rpmsg_channel_info *chinfo)
38{
39 if (WARN_ON(!rpdev))
40 return NULL;
41 if (!rpdev->ops || !rpdev->ops->create_channel) {
42 dev_err(&rpdev->dev, "no create_channel ops found\n");
43 return NULL;
44 }
45
46 return rpdev->ops->create_channel(rpdev, chinfo);
47}
48EXPORT_SYMBOL(rpmsg_create_channel);
49
50/**
51 * rpmsg_release_channel() - release a rpmsg channel
52 * using its name and address info.
53 * @rpdev: rpmsg device
54 * @chinfo: channel_info to bind
55 *
56 * Return: 0 on success or an appropriate error value.
57 */
58int rpmsg_release_channel(struct rpmsg_device *rpdev,
59 struct rpmsg_channel_info *chinfo)
60{
61 if (WARN_ON(!rpdev))
62 return -EINVAL;
63 if (!rpdev->ops || !rpdev->ops->release_channel) {
64 dev_err(&rpdev->dev, "no release_channel ops found\n");
65 return -ENXIO;
66 }
67
68 return rpdev->ops->release_channel(rpdev, chinfo);
69}
70EXPORT_SYMBOL(rpmsg_release_channel);
71
72/**
73 * rpmsg_create_ept() - create a new rpmsg_endpoint
74 * @rpdev: rpmsg channel device
75 * @cb: rx callback handler
76 * @priv: private data for the driver's use
77 * @chinfo: channel_info with the local rpmsg address to bind with @cb
78 *
79 * Every rpmsg address in the system is bound to an rx callback (so when
80 * inbound messages arrive, they are dispatched by the rpmsg bus using the
81 * appropriate callback handler) by means of an rpmsg_endpoint struct.
82 *
83 * This function allows drivers to create such an endpoint, and by that,
84 * bind a callback, and possibly some private data too, to an rpmsg address
85 * (either one that is known in advance, or one that will be dynamically
86 * assigned for them).
87 *
88 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
89 * is already created for them when they are probed by the rpmsg bus
90 * (using the rx callback provided when they registered to the rpmsg bus).
91 *
92 * So things should just work for simple drivers: they already have an
93 * endpoint, their rx callback is bound to their rpmsg address, and when
94 * relevant inbound messages arrive (i.e. messages which their dst address
95 * equals to the src address of their rpmsg channel), the driver's handler
96 * is invoked to process it.
97 *
98 * That said, more complicated drivers might need to allocate
99 * additional rpmsg addresses, and bind them to different rx callbacks.
100 * To accomplish that, those drivers need to call this function.
101 *
102 * Drivers should provide their @rpdev channel (so the new endpoint would belong
103 * to the same remote processor their channel belongs to), an rx callback
104 * function, an optional private data (which is provided back when the
105 * rx callback is invoked), and an address they want to bind with the
106 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
107 * dynamically assign them an available rpmsg address (drivers should have
108 * a very good reason why not to always use RPMSG_ADDR_ANY here).
109 *
110 * Return: a pointer to the endpoint on success, or NULL on error.
111 */
112struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
113 rpmsg_rx_cb_t cb, void *priv,
114 struct rpmsg_channel_info chinfo)
115{
116 if (WARN_ON(!rpdev))
117 return NULL;
118
119 return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
120}
121EXPORT_SYMBOL(rpmsg_create_ept);
122
123/**
124 * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
125 * @ept: endpoing to destroy
126 *
127 * Should be used by drivers to destroy an rpmsg endpoint previously
128 * created with rpmsg_create_ept(). As with other types of "free" NULL
129 * is a valid parameter.
130 */
131void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
132{
133 if (ept && ept->ops)
134 ept->ops->destroy_ept(ept);
135}
136EXPORT_SYMBOL(rpmsg_destroy_ept);
137
138/**
139 * rpmsg_send() - send a message across to the remote processor
140 * @ept: the rpmsg endpoint
141 * @data: payload of message
142 * @len: length of payload
143 *
144 * This function sends @data of length @len on the @ept endpoint.
145 * The message will be sent to the remote processor which the @ept
146 * endpoint belongs to, using @ept's address and its associated rpmsg
147 * device destination addresses.
148 * In case there are no TX buffers available, the function will block until
149 * one becomes available, or a timeout of 15 seconds elapses. When the latter
150 * happens, -ERESTARTSYS is returned.
151 *
152 * Can only be called from process context (for now).
153 *
154 * Return: 0 on success and an appropriate error value on failure.
155 */
156int rpmsg_send(struct rpmsg_endpoint *ept, const void *data, int len)
157{
158 if (WARN_ON(!ept))
159 return -EINVAL;
160 if (!ept->ops->send)
161 return -ENXIO;
162
163 return ept->ops->send(ept, data, len);
164}
165EXPORT_SYMBOL(rpmsg_send);
166
167/**
168 * rpmsg_sendto() - send a message across to the remote processor, specify dst
169 * @ept: the rpmsg endpoint
170 * @data: payload of message
171 * @len: length of payload
172 * @dst: destination address
173 *
174 * This function sends @data of length @len to the remote @dst address.
175 * The message will be sent to the remote processor which the @ept
176 * endpoint belongs to, using @ept's address as source.
177 * In case there are no TX buffers available, the function will block until
178 * one becomes available, or a timeout of 15 seconds elapses. When the latter
179 * happens, -ERESTARTSYS is returned.
180 *
181 * Can only be called from process context (for now).
182 *
183 * Return: 0 on success and an appropriate error value on failure.
184 */
185int rpmsg_sendto(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst)
186{
187 if (WARN_ON(!ept))
188 return -EINVAL;
189 if (!ept->ops->sendto)
190 return -ENXIO;
191
192 return ept->ops->sendto(ept, data, len, dst);
193}
194EXPORT_SYMBOL(rpmsg_sendto);
195
196/**
197 * rpmsg_trysend() - send a message across to the remote processor
198 * @ept: the rpmsg endpoint
199 * @data: payload of message
200 * @len: length of payload
201 *
202 * This function sends @data of length @len on the @ept endpoint.
203 * The message will be sent to the remote processor which the @ept
204 * endpoint belongs to, using @ept's address as source and its associated
205 * rpdev's address as destination.
206 * In case there are no TX buffers available, the function will immediately
207 * return -ENOMEM without waiting until one becomes available.
208 *
209 * Can only be called from process context (for now).
210 *
211 * Return: 0 on success and an appropriate error value on failure.
212 */
213int rpmsg_trysend(struct rpmsg_endpoint *ept, const void *data, int len)
214{
215 if (WARN_ON(!ept))
216 return -EINVAL;
217 if (!ept->ops->trysend)
218 return -ENXIO;
219
220 return ept->ops->trysend(ept, data, len);
221}
222EXPORT_SYMBOL(rpmsg_trysend);
223
224/**
225 * rpmsg_trysendto() - send a message across to the remote processor, specify dst
226 * @ept: the rpmsg endpoint
227 * @data: payload of message
228 * @len: length of payload
229 * @dst: destination address
230 *
231 * This function sends @data of length @len to the remote @dst address.
232 * The message will be sent to the remote processor which the @ept
233 * endpoint belongs to, using @ept's address as source.
234 * In case there are no TX buffers available, the function will immediately
235 * return -ENOMEM without waiting until one becomes available.
236 *
237 * Can only be called from process context (for now).
238 *
239 * Return: 0 on success and an appropriate error value on failure.
240 */
241int rpmsg_trysendto(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst)
242{
243 if (WARN_ON(!ept))
244 return -EINVAL;
245 if (!ept->ops->trysendto)
246 return -ENXIO;
247
248 return ept->ops->trysendto(ept, data, len, dst);
249}
250EXPORT_SYMBOL(rpmsg_trysendto);
251
252/**
253 * rpmsg_poll() - poll the endpoint's send buffers
254 * @ept: the rpmsg endpoint
255 * @filp: file for poll_wait()
256 * @wait: poll_table for poll_wait()
257 *
258 * Return: mask representing the current state of the endpoint's send buffers
259 */
260__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
261 poll_table *wait)
262{
263 if (WARN_ON(!ept))
264 return 0;
265 if (!ept->ops->poll)
266 return 0;
267
268 return ept->ops->poll(ept, filp, wait);
269}
270EXPORT_SYMBOL(rpmsg_poll);
271
272/**
273 * rpmsg_set_flow_control() - request remote to pause/resume transmission
274 * @ept: the rpmsg endpoint
275 * @pause: pause transmission
276 * @dst: destination address of the endpoint
277 *
278 * Return: 0 on success and an appropriate error value on failure.
279 */
280int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
281{
282 if (WARN_ON(!ept))
283 return -EINVAL;
284 if (!ept->ops->set_flow_control)
285 return -EOPNOTSUPP;
286
287 return ept->ops->set_flow_control(ept, pause, dst);
288}
289EXPORT_SYMBOL_GPL(rpmsg_set_flow_control);
290
291/**
292 * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
293 * @ept: the rpmsg endpoint
294 *
295 * This function returns maximum buffer size available for a single outgoing message.
296 *
297 * Return: the maximum transmission size on success and an appropriate error
298 * value on failure.
299 */
300
301ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
302{
303 if (WARN_ON(!ept))
304 return -EINVAL;
305 if (!ept->ops->get_mtu)
306 return -ENOTSUPP;
307
308 return ept->ops->get_mtu(ept);
309}
310EXPORT_SYMBOL(rpmsg_get_mtu);
311
312/*
313 * match a rpmsg channel with a channel info struct.
314 * this is used to make sure we're not creating rpmsg devices for channels
315 * that already exist.
316 */
317static int rpmsg_device_match(struct device *dev, const void *data)
318{
319 const struct rpmsg_channel_info *chinfo = data;
320 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
321
322 if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
323 return 0;
324
325 if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
326 return 0;
327
328 if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
329 return 0;
330
331 /* found a match ! */
332 return 1;
333}
334
335struct device *rpmsg_find_device(struct device *parent,
336 struct rpmsg_channel_info *chinfo)
337{
338 return device_find_child(parent, chinfo, rpmsg_device_match);
339
340}
341EXPORT_SYMBOL(rpmsg_find_device);
342
343/* sysfs show configuration fields */
344#define rpmsg_show_attr(field, path, format_string) \
345static ssize_t \
346field##_show(struct device *dev, \
347 struct device_attribute *attr, char *buf) \
348{ \
349 struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
350 \
351 return sprintf(buf, format_string, rpdev->path); \
352} \
353static DEVICE_ATTR_RO(field);
354
355/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
356rpmsg_show_attr(name, id.name, "%s\n");
357rpmsg_show_attr(src, src, "0x%x\n");
358rpmsg_show_attr(dst, dst, "0x%x\n");
359rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
360
361static ssize_t driver_override_store(struct device *dev,
362 struct device_attribute *attr,
363 const char *buf, size_t count)
364{
365 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
366 int ret;
367
368 ret = driver_set_override(dev, &rpdev->driver_override, buf, count);
369 if (ret)
370 return ret;
371
372 return count;
373}
374
375static ssize_t driver_override_show(struct device *dev,
376 struct device_attribute *attr, char *buf)
377{
378 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
379 ssize_t len;
380
381 device_lock(dev);
382 len = sysfs_emit(buf, "%s\n", rpdev->driver_override);
383 device_unlock(dev);
384 return len;
385}
386static DEVICE_ATTR_RW(driver_override);
387
388static ssize_t modalias_show(struct device *dev,
389 struct device_attribute *attr, char *buf)
390{
391 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
392 ssize_t len;
393
394 len = of_device_modalias(dev, buf, PAGE_SIZE);
395 if (len != -ENODEV)
396 return len;
397
398 return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
399}
400static DEVICE_ATTR_RO(modalias);
401
402static struct attribute *rpmsg_dev_attrs[] = {
403 &dev_attr_name.attr,
404 &dev_attr_modalias.attr,
405 &dev_attr_dst.attr,
406 &dev_attr_src.attr,
407 &dev_attr_announce.attr,
408 &dev_attr_driver_override.attr,
409 NULL,
410};
411ATTRIBUTE_GROUPS(rpmsg_dev);
412
413/* rpmsg devices and drivers are matched using the service name */
414static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
415 const struct rpmsg_device_id *id)
416{
417 return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
418}
419
420/* match rpmsg channel and rpmsg driver */
421static int rpmsg_dev_match(struct device *dev, const struct device_driver *drv)
422{
423 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
424 const struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
425 const struct rpmsg_device_id *ids = rpdrv->id_table;
426 unsigned int i;
427
428 if (rpdev->driver_override)
429 return !strcmp(rpdev->driver_override, drv->name);
430
431 if (ids)
432 for (i = 0; ids[i].name[0]; i++)
433 if (rpmsg_id_match(rpdev, &ids[i])) {
434 rpdev->id.driver_data = ids[i].driver_data;
435 return 1;
436 }
437
438 return of_driver_match_device(dev, drv);
439}
440
441static int rpmsg_uevent(const struct device *dev, struct kobj_uevent_env *env)
442{
443 const struct rpmsg_device *rpdev = to_rpmsg_device(dev);
444 int ret;
445
446 ret = of_device_uevent_modalias(dev, env);
447 if (ret != -ENODEV)
448 return ret;
449
450 return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
451 rpdev->id.name);
452}
453
454/*
455 * when an rpmsg driver is probed with a channel, we seamlessly create
456 * it an endpoint, binding its rx callback to a unique local rpmsg
457 * address.
458 *
459 * if we need to, we also announce about this channel to the remote
460 * processor (needed in case the driver is exposing an rpmsg service).
461 */
462static int rpmsg_dev_probe(struct device *dev)
463{
464 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
465 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
466 struct rpmsg_channel_info chinfo = {};
467 struct rpmsg_endpoint *ept = NULL;
468 int err;
469
470 err = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON |
471 PD_FLAG_DETACH_POWER_OFF);
472 if (err)
473 goto out;
474
475 if (rpdrv->callback) {
476 strscpy(chinfo.name, rpdev->id.name, sizeof(chinfo.name));
477 chinfo.src = rpdev->src;
478 chinfo.dst = RPMSG_ADDR_ANY;
479
480 ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
481 if (!ept) {
482 dev_err(dev, "failed to create endpoint\n");
483 err = -ENOMEM;
484 goto out;
485 }
486
487 rpdev->ept = ept;
488 rpdev->src = ept->addr;
489
490 ept->flow_cb = rpdrv->flowcontrol;
491 }
492
493 err = rpdrv->probe(rpdev);
494 if (err) {
495 dev_err(dev, "%s: failed: %d\n", __func__, err);
496 goto destroy_ept;
497 }
498
499 if (ept && rpdev->ops->announce_create) {
500 err = rpdev->ops->announce_create(rpdev);
501 if (err) {
502 dev_err(dev, "failed to announce creation\n");
503 goto remove_rpdev;
504 }
505 }
506
507 return 0;
508
509remove_rpdev:
510 if (rpdrv->remove)
511 rpdrv->remove(rpdev);
512destroy_ept:
513 if (ept)
514 rpmsg_destroy_ept(ept);
515out:
516 return err;
517}
518
519static void rpmsg_dev_remove(struct device *dev)
520{
521 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
522 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
523
524 if (rpdev->ops->announce_destroy)
525 rpdev->ops->announce_destroy(rpdev);
526
527 if (rpdrv->remove)
528 rpdrv->remove(rpdev);
529
530 if (rpdev->ept)
531 rpmsg_destroy_ept(rpdev->ept);
532}
533
534static const struct bus_type rpmsg_bus = {
535 .name = "rpmsg",
536 .match = rpmsg_dev_match,
537 .dev_groups = rpmsg_dev_groups,
538 .uevent = rpmsg_uevent,
539 .probe = rpmsg_dev_probe,
540 .remove = rpmsg_dev_remove,
541};
542
543/*
544 * A helper for registering rpmsg device with driver override and name.
545 * Drivers should not be using it, but instead rpmsg_register_device().
546 */
547int rpmsg_register_device_override(struct rpmsg_device *rpdev,
548 const char *driver_override)
549{
550 struct device *dev = &rpdev->dev;
551 int ret;
552
553 if (driver_override)
554 strscpy_pad(rpdev->id.name, driver_override, RPMSG_NAME_SIZE);
555
556 dev_set_name(dev, "%s.%s.%d.%d", dev_name(dev->parent),
557 rpdev->id.name, rpdev->src, rpdev->dst);
558
559 dev->bus = &rpmsg_bus;
560
561 device_initialize(dev);
562 if (driver_override) {
563 ret = driver_set_override(dev, &rpdev->driver_override,
564 driver_override,
565 strlen(driver_override));
566 if (ret) {
567 dev_err(dev, "device_set_override failed: %d\n", ret);
568 put_device(dev);
569 return ret;
570 }
571 }
572
573 ret = device_add(dev);
574 if (ret) {
575 dev_err(dev, "device_add failed: %d\n", ret);
576 kfree(rpdev->driver_override);
577 rpdev->driver_override = NULL;
578 put_device(dev);
579 }
580
581 return ret;
582}
583EXPORT_SYMBOL(rpmsg_register_device_override);
584
585int rpmsg_register_device(struct rpmsg_device *rpdev)
586{
587 return rpmsg_register_device_override(rpdev, NULL);
588}
589EXPORT_SYMBOL(rpmsg_register_device);
590
591/*
592 * find an existing channel using its name + address properties,
593 * and destroy it
594 */
595int rpmsg_unregister_device(struct device *parent,
596 struct rpmsg_channel_info *chinfo)
597{
598 struct device *dev;
599
600 dev = rpmsg_find_device(parent, chinfo);
601 if (!dev)
602 return -EINVAL;
603
604 device_unregister(dev);
605
606 put_device(dev);
607
608 return 0;
609}
610EXPORT_SYMBOL(rpmsg_unregister_device);
611
612/**
613 * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
614 * @rpdrv: pointer to a struct rpmsg_driver
615 * @owner: owning module/driver
616 *
617 * Return: 0 on success, and an appropriate error value on failure.
618 */
619int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
620{
621 rpdrv->drv.bus = &rpmsg_bus;
622 rpdrv->drv.owner = owner;
623 return driver_register(&rpdrv->drv);
624}
625EXPORT_SYMBOL(__register_rpmsg_driver);
626
627/**
628 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
629 * @rpdrv: pointer to a struct rpmsg_driver
630 *
631 * Return: 0 on success, and an appropriate error value on failure.
632 */
633void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
634{
635 driver_unregister(&rpdrv->drv);
636}
637EXPORT_SYMBOL(unregister_rpmsg_driver);
638
639
640static int __init rpmsg_init(void)
641{
642 int ret;
643
644 ret = class_register(&rpmsg_class);
645 if (ret) {
646 pr_err("failed to register rpmsg class\n");
647 return ret;
648 }
649
650 ret = bus_register(&rpmsg_bus);
651 if (ret) {
652 pr_err("failed to register rpmsg bus: %d\n", ret);
653 class_unregister(&rpmsg_class);
654 }
655 return ret;
656}
657postcore_initcall(rpmsg_init);
658
659static void __exit rpmsg_fini(void)
660{
661 bus_unregister(&rpmsg_bus);
662 class_unregister(&rpmsg_class);
663}
664module_exit(rpmsg_fini);
665
666MODULE_DESCRIPTION("remote processor messaging bus");
667MODULE_LICENSE("GPL v2");