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1// SPDX-License-Identifier: GPL-2.02/*3 * remote processor messaging bus4 *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 channel30 * using its name and address info.31 * @rpdev: rpmsg device32 * @chinfo: channel_info to bind33 *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 channel52 * using its name and address info.53 * @rpdev: rpmsg device54 * @chinfo: channel_info to bind55 *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_endpoint74 * @rpdev: rpmsg channel device75 * @cb: rx callback handler76 * @priv: private data for the driver's use77 * @chinfo: channel_info with the local rpmsg address to bind with @cb78 *79 * Every rpmsg address in the system is bound to an rx callback (so when80 * inbound messages arrive, they are dispatched by the rpmsg bus using the81 * 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 address85 * (either one that is known in advance, or one that will be dynamically86 * assigned for them).87 *88 * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint89 * is already created for them when they are probed by the rpmsg bus90 * (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 an93 * endpoint, their rx callback is bound to their rpmsg address, and when94 * relevant inbound messages arrive (i.e. messages which their dst address95 * equals to the src address of their rpmsg channel), the driver's handler96 * is invoked to process it.97 *98 * That said, more complicated drivers might need to allocate99 * 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 belong103 * to the same remote processor their channel belongs to), an rx callback104 * function, an optional private data (which is provided back when the105 * rx callback is invoked), and an address they want to bind with the106 * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will107 * dynamically assign them an available rpmsg address (drivers should have108 * 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 endpoint125 * @ept: endpoing to destroy126 *127 * Should be used by drivers to destroy an rpmsg endpoint previously128 * created with rpmsg_create_ept(). As with other types of "free" NULL129 * 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 processor140 * @ept: the rpmsg endpoint141 * @data: payload of message142 * @len: length of payload143 *144 * This function sends @data of length @len on the @ept endpoint.145 * The message will be sent to the remote processor which the @ept146 * endpoint belongs to, using @ept's address and its associated rpmsg147 * device destination addresses.148 * In case there are no TX buffers available, the function will block until149 * one becomes available, or a timeout of 15 seconds elapses. When the latter150 * 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 dst169 * @ept: the rpmsg endpoint170 * @data: payload of message171 * @len: length of payload172 * @dst: destination address173 *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 @ept176 * endpoint belongs to, using @ept's address as source.177 * In case there are no TX buffers available, the function will block until178 * one becomes available, or a timeout of 15 seconds elapses. When the latter179 * 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 addresses198 * @ept: the rpmsg endpoint199 * @src: source address200 * @dst: destination address201 * @data: payload of message202 * @len: length of payload203 *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 @ept207 * endpoint belongs to.208 * In case there are no TX buffers available, the function will block until209 * one becomes available, or a timeout of 15 seconds elapses. When the latter210 * 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 processor230 * @ept: the rpmsg endpoint231 * @data: payload of message232 * @len: length of payload233 *234 * This function sends @data of length @len on the @ept endpoint.235 * The message will be sent to the remote processor which the @ept236 * endpoint belongs to, using @ept's address as source and its associated237 * rpdev's address as destination.238 * In case there are no TX buffers available, the function will immediately239 * 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 dst258 * @ept: the rpmsg endpoint259 * @data: payload of message260 * @len: length of payload261 * @dst: destination address262 *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 @ept265 * endpoint belongs to, using @ept's address as source.266 * In case there are no TX buffers available, the function will immediately267 * 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 buffers286 * @ept: the rpmsg endpoint287 * @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 buffers291 */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 addresses306 * @ept: the rpmsg endpoint307 * @src: source address308 * @dst: destination address309 * @data: payload of message310 * @len: length of payload311 *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 @ept315 * endpoint belongs to.316 * In case there are no TX buffers available, the function will immediately317 * 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 transmission337 * @ept: the rpmsg endpoint338 * @pause: pause transmission339 * @dst: destination address of the endpoint340 *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 endpoint357 *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 error361 * 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 channels378 * 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 create531 * it an endpoint, binding its rx callback to a unique local rpmsg532 * address.533 *534 * if we need to, we also announce about this channel to the remote535 * 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 it670 */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 bus690 * @rpdrv: pointer to a struct rpmsg_driver691 * @owner: owning module/driver692 *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 bus705 * @rpdrv: pointer to a struct rpmsg_driver706 *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");744