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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, 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, 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_send_offchannel() - send a message using explicit src/dst addresses
198 * @ept: the rpmsg endpoint
199 * @src: source address
200 * @dst: destination address
201 * @data: payload of message
202 * @len: length of payload
203 *
204 * This function sends @data of length @len to the remote @dst address,
205 * and uses @src as the source address.
206 * The message will be sent to the remote processor which the @ept
207 * endpoint belongs to.
208 * In case there are no TX buffers available, the function will block until
209 * one becomes available, or a timeout of 15 seconds elapses. When the latter
210 * happens, -ERESTARTSYS is returned.
211 *
212 * Can only be called from process context (for now).
213 *
214 * Return: 0 on success and an appropriate error value on failure.
215 */
216int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
217 void *data, int len)
218{
219 if (WARN_ON(!ept))
220 return -EINVAL;
221 if (!ept->ops->send_offchannel)
222 return -ENXIO;
223
224 return ept->ops->send_offchannel(ept, src, dst, data, len);
225}
226EXPORT_SYMBOL(rpmsg_send_offchannel);
227
228/**
229 * rpmsg_trysend() - send a message across to the remote processor
230 * @ept: the rpmsg endpoint
231 * @data: payload of message
232 * @len: length of payload
233 *
234 * This function sends @data of length @len on the @ept endpoint.
235 * The message will be sent to the remote processor which the @ept
236 * endpoint belongs to, using @ept's address as source and its associated
237 * rpdev's address as destination.
238 * In case there are no TX buffers available, the function will immediately
239 * return -ENOMEM without waiting until one becomes available.
240 *
241 * Can only be called from process context (for now).
242 *
243 * Return: 0 on success and an appropriate error value on failure.
244 */
245int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
246{
247 if (WARN_ON(!ept))
248 return -EINVAL;
249 if (!ept->ops->trysend)
250 return -ENXIO;
251
252 return ept->ops->trysend(ept, data, len);
253}
254EXPORT_SYMBOL(rpmsg_trysend);
255
256/**
257 * rpmsg_trysendto() - send a message across to the remote processor, specify dst
258 * @ept: the rpmsg endpoint
259 * @data: payload of message
260 * @len: length of payload
261 * @dst: destination address
262 *
263 * This function sends @data of length @len to the remote @dst address.
264 * The message will be sent to the remote processor which the @ept
265 * endpoint belongs to, using @ept's address as source.
266 * In case there are no TX buffers available, the function will immediately
267 * return -ENOMEM without waiting until one becomes available.
268 *
269 * Can only be called from process context (for now).
270 *
271 * Return: 0 on success and an appropriate error value on failure.
272 */
273int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
274{
275 if (WARN_ON(!ept))
276 return -EINVAL;
277 if (!ept->ops->trysendto)
278 return -ENXIO;
279
280 return ept->ops->trysendto(ept, data, len, dst);
281}
282EXPORT_SYMBOL(rpmsg_trysendto);
283
284/**
285 * rpmsg_poll() - poll the endpoint's send buffers
286 * @ept: the rpmsg endpoint
287 * @filp: file for poll_wait()
288 * @wait: poll_table for poll_wait()
289 *
290 * Return: mask representing the current state of the endpoint's send buffers
291 */
292__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
293 poll_table *wait)
294{
295 if (WARN_ON(!ept))
296 return 0;
297 if (!ept->ops->poll)
298 return 0;
299
300 return ept->ops->poll(ept, filp, wait);
301}
302EXPORT_SYMBOL(rpmsg_poll);
303
304/**
305 * rpmsg_trysend_offchannel() - send a message using explicit src/dst addresses
306 * @ept: the rpmsg endpoint
307 * @src: source address
308 * @dst: destination address
309 * @data: payload of message
310 * @len: length of payload
311 *
312 * This function sends @data of length @len to the remote @dst address,
313 * and uses @src as the source address.
314 * The message will be sent to the remote processor which the @ept
315 * endpoint belongs to.
316 * In case there are no TX buffers available, the function will immediately
317 * return -ENOMEM without waiting until one becomes available.
318 *
319 * Can only be called from process context (for now).
320 *
321 * Return: 0 on success and an appropriate error value on failure.
322 */
323int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
324 void *data, int len)
325{
326 if (WARN_ON(!ept))
327 return -EINVAL;
328 if (!ept->ops->trysend_offchannel)
329 return -ENXIO;
330
331 return ept->ops->trysend_offchannel(ept, src, dst, data, len);
332}
333EXPORT_SYMBOL(rpmsg_trysend_offchannel);
334
335/**
336 * rpmsg_set_flow_control() - request remote to pause/resume transmission
337 * @ept: the rpmsg endpoint
338 * @pause: pause transmission
339 * @dst: destination address of the endpoint
340 *
341 * Return: 0 on success and an appropriate error value on failure.
342 */
343int rpmsg_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
344{
345 if (WARN_ON(!ept))
346 return -EINVAL;
347 if (!ept->ops->set_flow_control)
348 return -EOPNOTSUPP;
349
350 return ept->ops->set_flow_control(ept, pause, dst);
351}
352EXPORT_SYMBOL_GPL(rpmsg_set_flow_control);
353
354/**
355 * rpmsg_get_mtu() - get maximum transmission buffer size for sending message.
356 * @ept: the rpmsg endpoint
357 *
358 * This function returns maximum buffer size available for a single outgoing message.
359 *
360 * Return: the maximum transmission size on success and an appropriate error
361 * value on failure.
362 */
363
364ssize_t rpmsg_get_mtu(struct rpmsg_endpoint *ept)
365{
366 if (WARN_ON(!ept))
367 return -EINVAL;
368 if (!ept->ops->get_mtu)
369 return -ENOTSUPP;
370
371 return ept->ops->get_mtu(ept);
372}
373EXPORT_SYMBOL(rpmsg_get_mtu);
374
375/*
376 * match a rpmsg channel with a channel info struct.
377 * this is used to make sure we're not creating rpmsg devices for channels
378 * that already exist.
379 */
380static int rpmsg_device_match(struct device *dev, void *data)
381{
382 struct rpmsg_channel_info *chinfo = data;
383 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
384
385 if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
386 return 0;
387
388 if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
389 return 0;
390
391 if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
392 return 0;
393
394 /* found a match ! */
395 return 1;
396}
397
398struct device *rpmsg_find_device(struct device *parent,
399 struct rpmsg_channel_info *chinfo)
400{
401 return device_find_child(parent, chinfo, rpmsg_device_match);
402
403}
404EXPORT_SYMBOL(rpmsg_find_device);
405
406/* sysfs show configuration fields */
407#define rpmsg_show_attr(field, path, format_string) \
408static ssize_t \
409field##_show(struct device *dev, \
410 struct device_attribute *attr, char *buf) \
411{ \
412 struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
413 \
414 return sprintf(buf, format_string, rpdev->path); \
415} \
416static DEVICE_ATTR_RO(field);
417
418#define rpmsg_string_attr(field, member) \
419static ssize_t \
420field##_store(struct device *dev, struct device_attribute *attr, \
421 const char *buf, size_t sz) \
422{ \
423 struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
424 const char *old; \
425 char *new; \
426 \
427 new = kstrndup(buf, sz, GFP_KERNEL); \
428 if (!new) \
429 return -ENOMEM; \
430 new[strcspn(new, "\n")] = '\0'; \
431 \
432 device_lock(dev); \
433 old = rpdev->member; \
434 if (strlen(new)) { \
435 rpdev->member = new; \
436 } else { \
437 kfree(new); \
438 rpdev->member = NULL; \
439 } \
440 device_unlock(dev); \
441 \
442 kfree(old); \
443 \
444 return sz; \
445} \
446static ssize_t \
447field##_show(struct device *dev, \
448 struct device_attribute *attr, char *buf) \
449{ \
450 struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
451 \
452 return sprintf(buf, "%s\n", rpdev->member); \
453} \
454static DEVICE_ATTR_RW(field)
455
456/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
457rpmsg_show_attr(name, id.name, "%s\n");
458rpmsg_show_attr(src, src, "0x%x\n");
459rpmsg_show_attr(dst, dst, "0x%x\n");
460rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
461rpmsg_string_attr(driver_override, driver_override);
462
463static ssize_t modalias_show(struct device *dev,
464 struct device_attribute *attr, char *buf)
465{
466 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
467 ssize_t len;
468
469 len = of_device_modalias(dev, buf, PAGE_SIZE);
470 if (len != -ENODEV)
471 return len;
472
473 return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
474}
475static DEVICE_ATTR_RO(modalias);
476
477static struct attribute *rpmsg_dev_attrs[] = {
478 &dev_attr_name.attr,
479 &dev_attr_modalias.attr,
480 &dev_attr_dst.attr,
481 &dev_attr_src.attr,
482 &dev_attr_announce.attr,
483 &dev_attr_driver_override.attr,
484 NULL,
485};
486ATTRIBUTE_GROUPS(rpmsg_dev);
487
488/* rpmsg devices and drivers are matched using the service name */
489static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
490 const struct rpmsg_device_id *id)
491{
492 return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
493}
494
495/* match rpmsg channel and rpmsg driver */
496static int rpmsg_dev_match(struct device *dev, const struct device_driver *drv)
497{
498 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
499 const struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
500 const struct rpmsg_device_id *ids = rpdrv->id_table;
501 unsigned int i;
502
503 if (rpdev->driver_override)
504 return !strcmp(rpdev->driver_override, drv->name);
505
506 if (ids)
507 for (i = 0; ids[i].name[0]; i++)
508 if (rpmsg_id_match(rpdev, &ids[i])) {
509 rpdev->id.driver_data = ids[i].driver_data;
510 return 1;
511 }
512
513 return of_driver_match_device(dev, drv);
514}
515
516static int rpmsg_uevent(const struct device *dev, struct kobj_uevent_env *env)
517{
518 const struct rpmsg_device *rpdev = to_rpmsg_device(dev);
519 int ret;
520
521 ret = of_device_uevent_modalias(dev, env);
522 if (ret != -ENODEV)
523 return ret;
524
525 return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
526 rpdev->id.name);
527}
528
529/*
530 * when an rpmsg driver is probed with a channel, we seamlessly create
531 * it an endpoint, binding its rx callback to a unique local rpmsg
532 * address.
533 *
534 * if we need to, we also announce about this channel to the remote
535 * processor (needed in case the driver is exposing an rpmsg service).
536 */
537static int rpmsg_dev_probe(struct device *dev)
538{
539 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
540 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
541 struct rpmsg_channel_info chinfo = {};
542 struct rpmsg_endpoint *ept = NULL;
543 int err;
544
545 err = dev_pm_domain_attach(dev, true);
546 if (err)
547 goto out;
548
549 if (rpdrv->callback) {
550 strscpy(chinfo.name, rpdev->id.name, sizeof(chinfo.name));
551 chinfo.src = rpdev->src;
552 chinfo.dst = RPMSG_ADDR_ANY;
553
554 ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
555 if (!ept) {
556 dev_err(dev, "failed to create endpoint\n");
557 err = -ENOMEM;
558 goto out;
559 }
560
561 rpdev->ept = ept;
562 rpdev->src = ept->addr;
563
564 ept->flow_cb = rpdrv->flowcontrol;
565 }
566
567 err = rpdrv->probe(rpdev);
568 if (err) {
569 dev_err(dev, "%s: failed: %d\n", __func__, err);
570 goto destroy_ept;
571 }
572
573 if (ept && rpdev->ops->announce_create) {
574 err = rpdev->ops->announce_create(rpdev);
575 if (err) {
576 dev_err(dev, "failed to announce creation\n");
577 goto remove_rpdev;
578 }
579 }
580
581 return 0;
582
583remove_rpdev:
584 if (rpdrv->remove)
585 rpdrv->remove(rpdev);
586destroy_ept:
587 if (ept)
588 rpmsg_destroy_ept(ept);
589out:
590 return err;
591}
592
593static void rpmsg_dev_remove(struct device *dev)
594{
595 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
596 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
597
598 if (rpdev->ops->announce_destroy)
599 rpdev->ops->announce_destroy(rpdev);
600
601 if (rpdrv->remove)
602 rpdrv->remove(rpdev);
603
604 dev_pm_domain_detach(dev, true);
605
606 if (rpdev->ept)
607 rpmsg_destroy_ept(rpdev->ept);
608}
609
610static const struct bus_type rpmsg_bus = {
611 .name = "rpmsg",
612 .match = rpmsg_dev_match,
613 .dev_groups = rpmsg_dev_groups,
614 .uevent = rpmsg_uevent,
615 .probe = rpmsg_dev_probe,
616 .remove = rpmsg_dev_remove,
617};
618
619/*
620 * A helper for registering rpmsg device with driver override and name.
621 * Drivers should not be using it, but instead rpmsg_register_device().
622 */
623int rpmsg_register_device_override(struct rpmsg_device *rpdev,
624 const char *driver_override)
625{
626 struct device *dev = &rpdev->dev;
627 int ret;
628
629 if (driver_override)
630 strscpy_pad(rpdev->id.name, driver_override, RPMSG_NAME_SIZE);
631
632 dev_set_name(dev, "%s.%s.%d.%d", dev_name(dev->parent),
633 rpdev->id.name, rpdev->src, rpdev->dst);
634
635 dev->bus = &rpmsg_bus;
636
637 device_initialize(dev);
638 if (driver_override) {
639 ret = driver_set_override(dev, &rpdev->driver_override,
640 driver_override,
641 strlen(driver_override));
642 if (ret) {
643 dev_err(dev, "device_set_override failed: %d\n", ret);
644 put_device(dev);
645 return ret;
646 }
647 }
648
649 ret = device_add(dev);
650 if (ret) {
651 dev_err(dev, "device_add failed: %d\n", ret);
652 kfree(rpdev->driver_override);
653 rpdev->driver_override = NULL;
654 put_device(dev);
655 }
656
657 return ret;
658}
659EXPORT_SYMBOL(rpmsg_register_device_override);
660
661int rpmsg_register_device(struct rpmsg_device *rpdev)
662{
663 return rpmsg_register_device_override(rpdev, NULL);
664}
665EXPORT_SYMBOL(rpmsg_register_device);
666
667/*
668 * find an existing channel using its name + address properties,
669 * and destroy it
670 */
671int rpmsg_unregister_device(struct device *parent,
672 struct rpmsg_channel_info *chinfo)
673{
674 struct device *dev;
675
676 dev = rpmsg_find_device(parent, chinfo);
677 if (!dev)
678 return -EINVAL;
679
680 device_unregister(dev);
681
682 put_device(dev);
683
684 return 0;
685}
686EXPORT_SYMBOL(rpmsg_unregister_device);
687
688/**
689 * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
690 * @rpdrv: pointer to a struct rpmsg_driver
691 * @owner: owning module/driver
692 *
693 * Return: 0 on success, and an appropriate error value on failure.
694 */
695int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
696{
697 rpdrv->drv.bus = &rpmsg_bus;
698 rpdrv->drv.owner = owner;
699 return driver_register(&rpdrv->drv);
700}
701EXPORT_SYMBOL(__register_rpmsg_driver);
702
703/**
704 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
705 * @rpdrv: pointer to a struct rpmsg_driver
706 *
707 * Return: 0 on success, and an appropriate error value on failure.
708 */
709void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
710{
711 driver_unregister(&rpdrv->drv);
712}
713EXPORT_SYMBOL(unregister_rpmsg_driver);
714
715
716static int __init rpmsg_init(void)
717{
718 int ret;
719
720 ret = class_register(&rpmsg_class);
721 if (ret) {
722 pr_err("failed to register rpmsg class\n");
723 return ret;
724 }
725
726 ret = bus_register(&rpmsg_bus);
727 if (ret) {
728 pr_err("failed to register rpmsg bus: %d\n", ret);
729 class_destroy(&rpmsg_class);
730 }
731 return ret;
732}
733postcore_initcall(rpmsg_init);
734
735static void __exit rpmsg_fini(void)
736{
737 bus_unregister(&rpmsg_bus);
738 class_destroy(&rpmsg_class);
739}
740module_exit(rpmsg_fini);
741
742MODULE_DESCRIPTION("remote processor messaging bus");
743MODULE_LICENSE("GPL v2");
1/*
2 * remote processor messaging bus
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
6 *
7 * Ohad Ben-Cohen <ohad@wizery.com>
8 * Brian Swetland <swetland@google.com>
9 *
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 */
19
20#define pr_fmt(fmt) "%s: " fmt, __func__
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/rpmsg.h>
25#include <linux/of_device.h>
26#include <linux/slab.h>
27
28#include "rpmsg_internal.h"
29
30/**
31 * rpmsg_create_ept() - create a new rpmsg_endpoint
32 * @rpdev: rpmsg channel device
33 * @cb: rx callback handler
34 * @priv: private data for the driver's use
35 * @chinfo: channel_info with the local rpmsg address to bind with @cb
36 *
37 * Every rpmsg address in the system is bound to an rx callback (so when
38 * inbound messages arrive, they are dispatched by the rpmsg bus using the
39 * appropriate callback handler) by means of an rpmsg_endpoint struct.
40 *
41 * This function allows drivers to create such an endpoint, and by that,
42 * bind a callback, and possibly some private data too, to an rpmsg address
43 * (either one that is known in advance, or one that will be dynamically
44 * assigned for them).
45 *
46 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
47 * is already created for them when they are probed by the rpmsg bus
48 * (using the rx callback provided when they registered to the rpmsg bus).
49 *
50 * So things should just work for simple drivers: they already have an
51 * endpoint, their rx callback is bound to their rpmsg address, and when
52 * relevant inbound messages arrive (i.e. messages which their dst address
53 * equals to the src address of their rpmsg channel), the driver's handler
54 * is invoked to process it.
55 *
56 * That said, more complicated drivers might do need to allocate
57 * additional rpmsg addresses, and bind them to different rx callbacks.
58 * To accomplish that, those drivers need to call this function.
59 *
60 * Drivers should provide their @rpdev channel (so the new endpoint would belong
61 * to the same remote processor their channel belongs to), an rx callback
62 * function, an optional private data (which is provided back when the
63 * rx callback is invoked), and an address they want to bind with the
64 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
65 * dynamically assign them an available rpmsg address (drivers should have
66 * a very good reason why not to always use RPMSG_ADDR_ANY here).
67 *
68 * Returns a pointer to the endpoint on success, or NULL on error.
69 */
70struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
71 rpmsg_rx_cb_t cb, void *priv,
72 struct rpmsg_channel_info chinfo)
73{
74 if (WARN_ON(!rpdev))
75 return NULL;
76
77 return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
78}
79EXPORT_SYMBOL(rpmsg_create_ept);
80
81/**
82 * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
83 * @ept: endpoing to destroy
84 *
85 * Should be used by drivers to destroy an rpmsg endpoint previously
86 * created with rpmsg_create_ept(). As with other types of "free" NULL
87 * is a valid parameter.
88 */
89void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
90{
91 if (ept)
92 ept->ops->destroy_ept(ept);
93}
94EXPORT_SYMBOL(rpmsg_destroy_ept);
95
96/**
97 * rpmsg_send() - send a message across to the remote processor
98 * @ept: the rpmsg endpoint
99 * @data: payload of message
100 * @len: length of payload
101 *
102 * This function sends @data of length @len on the @ept endpoint.
103 * The message will be sent to the remote processor which the @ept
104 * endpoint belongs to, using @ept's address and its associated rpmsg
105 * device destination addresses.
106 * In case there are no TX buffers available, the function will block until
107 * one becomes available, or a timeout of 15 seconds elapses. When the latter
108 * happens, -ERESTARTSYS is returned.
109 *
110 * Can only be called from process context (for now).
111 *
112 * Returns 0 on success and an appropriate error value on failure.
113 */
114int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
115{
116 if (WARN_ON(!ept))
117 return -EINVAL;
118 if (!ept->ops->send)
119 return -ENXIO;
120
121 return ept->ops->send(ept, data, len);
122}
123EXPORT_SYMBOL(rpmsg_send);
124
125/**
126 * rpmsg_sendto() - send a message across to the remote processor, specify dst
127 * @ept: the rpmsg endpoint
128 * @data: payload of message
129 * @len: length of payload
130 * @dst: destination address
131 *
132 * This function sends @data of length @len to the remote @dst address.
133 * The message will be sent to the remote processor which the @ept
134 * endpoint belongs to, using @ept's address as source.
135 * In case there are no TX buffers available, the function will block until
136 * one becomes available, or a timeout of 15 seconds elapses. When the latter
137 * happens, -ERESTARTSYS is returned.
138 *
139 * Can only be called from process context (for now).
140 *
141 * Returns 0 on success and an appropriate error value on failure.
142 */
143int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
144{
145 if (WARN_ON(!ept))
146 return -EINVAL;
147 if (!ept->ops->sendto)
148 return -ENXIO;
149
150 return ept->ops->sendto(ept, data, len, dst);
151}
152EXPORT_SYMBOL(rpmsg_sendto);
153
154/**
155 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
156 * @ept: the rpmsg endpoint
157 * @src: source address
158 * @dst: destination address
159 * @data: payload of message
160 * @len: length of payload
161 *
162 * This function sends @data of length @len to the remote @dst address,
163 * and uses @src as the source address.
164 * The message will be sent to the remote processor which the @ept
165 * endpoint belongs to.
166 * In case there are no TX buffers available, the function will block until
167 * one becomes available, or a timeout of 15 seconds elapses. When the latter
168 * happens, -ERESTARTSYS is returned.
169 *
170 * Can only be called from process context (for now).
171 *
172 * Returns 0 on success and an appropriate error value on failure.
173 */
174int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
175 void *data, int len)
176{
177 if (WARN_ON(!ept))
178 return -EINVAL;
179 if (!ept->ops->send_offchannel)
180 return -ENXIO;
181
182 return ept->ops->send_offchannel(ept, src, dst, data, len);
183}
184EXPORT_SYMBOL(rpmsg_send_offchannel);
185
186/**
187 * rpmsg_send() - send a message across to the remote processor
188 * @ept: the rpmsg endpoint
189 * @data: payload of message
190 * @len: length of payload
191 *
192 * This function sends @data of length @len on the @ept endpoint.
193 * The message will be sent to the remote processor which the @ept
194 * endpoint belongs to, using @ept's address as source and its associated
195 * rpdev's address as destination.
196 * In case there are no TX buffers available, the function will immediately
197 * return -ENOMEM without waiting until one becomes available.
198 *
199 * Can only be called from process context (for now).
200 *
201 * Returns 0 on success and an appropriate error value on failure.
202 */
203int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
204{
205 if (WARN_ON(!ept))
206 return -EINVAL;
207 if (!ept->ops->trysend)
208 return -ENXIO;
209
210 return ept->ops->trysend(ept, data, len);
211}
212EXPORT_SYMBOL(rpmsg_trysend);
213
214/**
215 * rpmsg_sendto() - send a message across to the remote processor, specify dst
216 * @ept: the rpmsg endpoint
217 * @data: payload of message
218 * @len: length of payload
219 * @dst: destination address
220 *
221 * This function sends @data of length @len to the remote @dst address.
222 * The message will be sent to the remote processor which the @ept
223 * endpoint belongs to, using @ept's address as source.
224 * In case there are no TX buffers available, the function will immediately
225 * return -ENOMEM without waiting until one becomes available.
226 *
227 * Can only be called from process context (for now).
228 *
229 * Returns 0 on success and an appropriate error value on failure.
230 */
231int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
232{
233 if (WARN_ON(!ept))
234 return -EINVAL;
235 if (!ept->ops->trysendto)
236 return -ENXIO;
237
238 return ept->ops->trysendto(ept, data, len, dst);
239}
240EXPORT_SYMBOL(rpmsg_trysendto);
241
242/**
243 * rpmsg_poll() - poll the endpoint's send buffers
244 * @ept: the rpmsg endpoint
245 * @filp: file for poll_wait()
246 * @wait: poll_table for poll_wait()
247 *
248 * Returns mask representing the current state of the endpoint's send buffers
249 */
250__poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
251 poll_table *wait)
252{
253 if (WARN_ON(!ept))
254 return 0;
255 if (!ept->ops->poll)
256 return 0;
257
258 return ept->ops->poll(ept, filp, wait);
259}
260EXPORT_SYMBOL(rpmsg_poll);
261
262/**
263 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
264 * @ept: the rpmsg endpoint
265 * @src: source address
266 * @dst: destination address
267 * @data: payload of message
268 * @len: length of payload
269 *
270 * This function sends @data of length @len to the remote @dst address,
271 * and uses @src as the source address.
272 * The message will be sent to the remote processor which the @ept
273 * endpoint belongs to.
274 * In case there are no TX buffers available, the function will immediately
275 * return -ENOMEM without waiting until one becomes available.
276 *
277 * Can only be called from process context (for now).
278 *
279 * Returns 0 on success and an appropriate error value on failure.
280 */
281int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
282 void *data, int len)
283{
284 if (WARN_ON(!ept))
285 return -EINVAL;
286 if (!ept->ops->trysend_offchannel)
287 return -ENXIO;
288
289 return ept->ops->trysend_offchannel(ept, src, dst, data, len);
290}
291EXPORT_SYMBOL(rpmsg_trysend_offchannel);
292
293/*
294 * match an rpmsg channel with a channel info struct.
295 * this is used to make sure we're not creating rpmsg devices for channels
296 * that already exist.
297 */
298static int rpmsg_device_match(struct device *dev, void *data)
299{
300 struct rpmsg_channel_info *chinfo = data;
301 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
302
303 if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
304 return 0;
305
306 if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
307 return 0;
308
309 if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
310 return 0;
311
312 /* found a match ! */
313 return 1;
314}
315
316struct device *rpmsg_find_device(struct device *parent,
317 struct rpmsg_channel_info *chinfo)
318{
319 return device_find_child(parent, chinfo, rpmsg_device_match);
320
321}
322EXPORT_SYMBOL(rpmsg_find_device);
323
324/* sysfs show configuration fields */
325#define rpmsg_show_attr(field, path, format_string) \
326static ssize_t \
327field##_show(struct device *dev, \
328 struct device_attribute *attr, char *buf) \
329{ \
330 struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
331 \
332 return sprintf(buf, format_string, rpdev->path); \
333} \
334static DEVICE_ATTR_RO(field);
335
336/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
337rpmsg_show_attr(name, id.name, "%s\n");
338rpmsg_show_attr(src, src, "0x%x\n");
339rpmsg_show_attr(dst, dst, "0x%x\n");
340rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
341
342static ssize_t modalias_show(struct device *dev,
343 struct device_attribute *attr, char *buf)
344{
345 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
346 ssize_t len;
347
348 len = of_device_modalias(dev, buf, PAGE_SIZE);
349 if (len != -ENODEV)
350 return len;
351
352 return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
353}
354static DEVICE_ATTR_RO(modalias);
355
356static struct attribute *rpmsg_dev_attrs[] = {
357 &dev_attr_name.attr,
358 &dev_attr_modalias.attr,
359 &dev_attr_dst.attr,
360 &dev_attr_src.attr,
361 &dev_attr_announce.attr,
362 NULL,
363};
364ATTRIBUTE_GROUPS(rpmsg_dev);
365
366/* rpmsg devices and drivers are matched using the service name */
367static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
368 const struct rpmsg_device_id *id)
369{
370 return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
371}
372
373/* match rpmsg channel and rpmsg driver */
374static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
375{
376 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
377 struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
378 const struct rpmsg_device_id *ids = rpdrv->id_table;
379 unsigned int i;
380
381 if (rpdev->driver_override)
382 return !strcmp(rpdev->driver_override, drv->name);
383
384 if (ids)
385 for (i = 0; ids[i].name[0]; i++)
386 if (rpmsg_id_match(rpdev, &ids[i]))
387 return 1;
388
389 return of_driver_match_device(dev, drv);
390}
391
392static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
393{
394 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
395 int ret;
396
397 ret = of_device_uevent_modalias(dev, env);
398 if (ret != -ENODEV)
399 return ret;
400
401 return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
402 rpdev->id.name);
403}
404
405/*
406 * when an rpmsg driver is probed with a channel, we seamlessly create
407 * it an endpoint, binding its rx callback to a unique local rpmsg
408 * address.
409 *
410 * if we need to, we also announce about this channel to the remote
411 * processor (needed in case the driver is exposing an rpmsg service).
412 */
413static int rpmsg_dev_probe(struct device *dev)
414{
415 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
416 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
417 struct rpmsg_channel_info chinfo = {};
418 struct rpmsg_endpoint *ept = NULL;
419 int err;
420
421 if (rpdrv->callback) {
422 strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
423 chinfo.src = rpdev->src;
424 chinfo.dst = RPMSG_ADDR_ANY;
425
426 ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
427 if (!ept) {
428 dev_err(dev, "failed to create endpoint\n");
429 err = -ENOMEM;
430 goto out;
431 }
432
433 rpdev->ept = ept;
434 rpdev->src = ept->addr;
435 }
436
437 err = rpdrv->probe(rpdev);
438 if (err) {
439 dev_err(dev, "%s: failed: %d\n", __func__, err);
440 if (ept)
441 rpmsg_destroy_ept(ept);
442 goto out;
443 }
444
445 if (ept && rpdev->ops->announce_create)
446 err = rpdev->ops->announce_create(rpdev);
447out:
448 return err;
449}
450
451static int rpmsg_dev_remove(struct device *dev)
452{
453 struct rpmsg_device *rpdev = to_rpmsg_device(dev);
454 struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
455 int err = 0;
456
457 if (rpdev->ops->announce_destroy)
458 err = rpdev->ops->announce_destroy(rpdev);
459
460 rpdrv->remove(rpdev);
461
462 if (rpdev->ept)
463 rpmsg_destroy_ept(rpdev->ept);
464
465 return err;
466}
467
468static struct bus_type rpmsg_bus = {
469 .name = "rpmsg",
470 .match = rpmsg_dev_match,
471 .dev_groups = rpmsg_dev_groups,
472 .uevent = rpmsg_uevent,
473 .probe = rpmsg_dev_probe,
474 .remove = rpmsg_dev_remove,
475};
476
477int rpmsg_register_device(struct rpmsg_device *rpdev)
478{
479 struct device *dev = &rpdev->dev;
480 int ret;
481
482 dev_set_name(&rpdev->dev, "%s.%s.%d.%d", dev_name(dev->parent),
483 rpdev->id.name, rpdev->src, rpdev->dst);
484
485 rpdev->dev.bus = &rpmsg_bus;
486
487 ret = device_register(&rpdev->dev);
488 if (ret) {
489 dev_err(dev, "device_register failed: %d\n", ret);
490 put_device(&rpdev->dev);
491 }
492
493 return ret;
494}
495EXPORT_SYMBOL(rpmsg_register_device);
496
497/*
498 * find an existing channel using its name + address properties,
499 * and destroy it
500 */
501int rpmsg_unregister_device(struct device *parent,
502 struct rpmsg_channel_info *chinfo)
503{
504 struct device *dev;
505
506 dev = rpmsg_find_device(parent, chinfo);
507 if (!dev)
508 return -EINVAL;
509
510 device_unregister(dev);
511
512 put_device(dev);
513
514 return 0;
515}
516EXPORT_SYMBOL(rpmsg_unregister_device);
517
518/**
519 * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
520 * @rpdrv: pointer to a struct rpmsg_driver
521 * @owner: owning module/driver
522 *
523 * Returns 0 on success, and an appropriate error value on failure.
524 */
525int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
526{
527 rpdrv->drv.bus = &rpmsg_bus;
528 rpdrv->drv.owner = owner;
529 return driver_register(&rpdrv->drv);
530}
531EXPORT_SYMBOL(__register_rpmsg_driver);
532
533/**
534 * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
535 * @rpdrv: pointer to a struct rpmsg_driver
536 *
537 * Returns 0 on success, and an appropriate error value on failure.
538 */
539void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
540{
541 driver_unregister(&rpdrv->drv);
542}
543EXPORT_SYMBOL(unregister_rpmsg_driver);
544
545
546static int __init rpmsg_init(void)
547{
548 int ret;
549
550 ret = bus_register(&rpmsg_bus);
551 if (ret)
552 pr_err("failed to register rpmsg bus: %d\n", ret);
553
554 return ret;
555}
556postcore_initcall(rpmsg_init);
557
558static void __exit rpmsg_fini(void)
559{
560 bus_unregister(&rpmsg_bus);
561}
562module_exit(rpmsg_fini);
563
564MODULE_DESCRIPTION("remote processor messaging bus");
565MODULE_LICENSE("GPL v2");