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