// SPDX-License-Identifier: GPL-2.0 /* * remote processor messaging bus * * Copyright (C) 2011 Texas Instruments, Inc. * Copyright (C) 2011 Google, Inc. * * Ohad Ben-Cohen * Brian Swetland */ #define pr_fmt(fmt) "%s: " fmt, __func__ #include #include #include #include #include #include #include "rpmsg_internal.h" /** * rpmsg_create_ept() - create a new rpmsg_endpoint * @rpdev: rpmsg channel device * @cb: rx callback handler * @priv: private data for the driver's use * @chinfo: channel_info with the local rpmsg address to bind with @cb * * Every rpmsg address in the system is bound to an rx callback (so when * inbound messages arrive, they are dispatched by the rpmsg bus using the * appropriate callback handler) by means of an rpmsg_endpoint struct. * * This function allows drivers to create such an endpoint, and by that, * bind a callback, and possibly some private data too, to an rpmsg address * (either one that is known in advance, or one that will be dynamically * assigned for them). * * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint * is already created for them when they are probed by the rpmsg bus * (using the rx callback provided when they registered to the rpmsg bus). * * So things should just work for simple drivers: they already have an * endpoint, their rx callback is bound to their rpmsg address, and when * relevant inbound messages arrive (i.e. messages which their dst address * equals to the src address of their rpmsg channel), the driver's handler * is invoked to process it. * * That said, more complicated drivers might need to allocate * additional rpmsg addresses, and bind them to different rx callbacks. * To accomplish that, those drivers need to call this function. * * Drivers should provide their @rpdev channel (so the new endpoint would belong * to the same remote processor their channel belongs to), an rx callback * function, an optional private data (which is provided back when the * rx callback is invoked), and an address they want to bind with the * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will * dynamically assign them an available rpmsg address (drivers should have * a very good reason why not to always use RPMSG_ADDR_ANY here). * * Returns a pointer to the endpoint on success, or NULL on error. */ struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev, rpmsg_rx_cb_t cb, void *priv, struct rpmsg_channel_info chinfo) { if (WARN_ON(!rpdev)) return NULL; return rpdev->ops->create_ept(rpdev, cb, priv, chinfo); } EXPORT_SYMBOL(rpmsg_create_ept); /** * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint * @ept: endpoing to destroy * * Should be used by drivers to destroy an rpmsg endpoint previously * created with rpmsg_create_ept(). As with other types of "free" NULL * is a valid parameter. */ void rpmsg_destroy_ept(struct rpmsg_endpoint *ept) { if (ept) ept->ops->destroy_ept(ept); } EXPORT_SYMBOL(rpmsg_destroy_ept); /** * rpmsg_send() - send a message across to the remote processor * @ept: the rpmsg endpoint * @data: payload of message * @len: length of payload * * This function sends @data of length @len on the @ept endpoint. * The message will be sent to the remote processor which the @ept * endpoint belongs to, using @ept's address and its associated rpmsg * device destination addresses. * In case there are no TX buffers available, the function will block until * one becomes available, or a timeout of 15 seconds elapses. When the latter * happens, -ERESTARTSYS is returned. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->send) return -ENXIO; return ept->ops->send(ept, data, len); } EXPORT_SYMBOL(rpmsg_send); /** * rpmsg_sendto() - send a message across to the remote processor, specify dst * @ept: the rpmsg endpoint * @data: payload of message * @len: length of payload * @dst: destination address * * This function sends @data of length @len to the remote @dst address. * The message will be sent to the remote processor which the @ept * endpoint belongs to, using @ept's address as source. * In case there are no TX buffers available, the function will block until * one becomes available, or a timeout of 15 seconds elapses. When the latter * happens, -ERESTARTSYS is returned. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->sendto) return -ENXIO; return ept->ops->sendto(ept, data, len, dst); } EXPORT_SYMBOL(rpmsg_sendto); /** * rpmsg_send_offchannel() - send a message using explicit src/dst addresses * @ept: the rpmsg endpoint * @src: source address * @dst: destination address * @data: payload of message * @len: length of payload * * This function sends @data of length @len to the remote @dst address, * and uses @src as the source address. * The message will be sent to the remote processor which the @ept * endpoint belongs to. * In case there are no TX buffers available, the function will block until * one becomes available, or a timeout of 15 seconds elapses. When the latter * happens, -ERESTARTSYS is returned. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->send_offchannel) return -ENXIO; return ept->ops->send_offchannel(ept, src, dst, data, len); } EXPORT_SYMBOL(rpmsg_send_offchannel); /** * rpmsg_trysend() - send a message across to the remote processor * @ept: the rpmsg endpoint * @data: payload of message * @len: length of payload * * This function sends @data of length @len on the @ept endpoint. * The message will be sent to the remote processor which the @ept * endpoint belongs to, using @ept's address as source and its associated * rpdev's address as destination. * In case there are no TX buffers available, the function will immediately * return -ENOMEM without waiting until one becomes available. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->trysend) return -ENXIO; return ept->ops->trysend(ept, data, len); } EXPORT_SYMBOL(rpmsg_trysend); /** * rpmsg_trysendto() - send a message across to the remote processor, specify dst * @ept: the rpmsg endpoint * @data: payload of message * @len: length of payload * @dst: destination address * * This function sends @data of length @len to the remote @dst address. * The message will be sent to the remote processor which the @ept * endpoint belongs to, using @ept's address as source. * In case there are no TX buffers available, the function will immediately * return -ENOMEM without waiting until one becomes available. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->trysendto) return -ENXIO; return ept->ops->trysendto(ept, data, len, dst); } EXPORT_SYMBOL(rpmsg_trysendto); /** * rpmsg_poll() - poll the endpoint's send buffers * @ept: the rpmsg endpoint * @filp: file for poll_wait() * @wait: poll_table for poll_wait() * * Returns mask representing the current state of the endpoint's send buffers */ __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp, poll_table *wait) { if (WARN_ON(!ept)) return 0; if (!ept->ops->poll) return 0; return ept->ops->poll(ept, filp, wait); } EXPORT_SYMBOL(rpmsg_poll); /** * rpmsg_trysend_offchannel() - send a message using explicit src/dst addresses * @ept: the rpmsg endpoint * @src: source address * @dst: destination address * @data: payload of message * @len: length of payload * * This function sends @data of length @len to the remote @dst address, * and uses @src as the source address. * The message will be sent to the remote processor which the @ept * endpoint belongs to. * In case there are no TX buffers available, the function will immediately * return -ENOMEM without waiting until one becomes available. * * Can only be called from process context (for now). * * Returns 0 on success and an appropriate error value on failure. */ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, void *data, int len) { if (WARN_ON(!ept)) return -EINVAL; if (!ept->ops->trysend_offchannel) return -ENXIO; return ept->ops->trysend_offchannel(ept, src, dst, data, len); } EXPORT_SYMBOL(rpmsg_trysend_offchannel); /* * match an rpmsg channel with a channel info struct. * this is used to make sure we're not creating rpmsg devices for channels * that already exist. */ static int rpmsg_device_match(struct device *dev, void *data) { struct rpmsg_channel_info *chinfo = data; struct rpmsg_device *rpdev = to_rpmsg_device(dev); if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src) return 0; if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst) return 0; if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE)) return 0; /* found a match ! */ return 1; } struct device *rpmsg_find_device(struct device *parent, struct rpmsg_channel_info *chinfo) { return device_find_child(parent, chinfo, rpmsg_device_match); } EXPORT_SYMBOL(rpmsg_find_device); /* sysfs show configuration fields */ #define rpmsg_show_attr(field, path, format_string) \ static ssize_t \ field##_show(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \ \ return sprintf(buf, format_string, rpdev->path); \ } \ static DEVICE_ATTR_RO(field); #define rpmsg_string_attr(field, member) \ static ssize_t \ field##_store(struct device *dev, struct device_attribute *attr, \ const char *buf, size_t sz) \ { \ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \ char *new, *old; \ \ new = kstrndup(buf, sz, GFP_KERNEL); \ if (!new) \ return -ENOMEM; \ new[strcspn(new, "\n")] = '\0'; \ \ device_lock(dev); \ old = rpdev->member; \ if (strlen(new)) { \ rpdev->member = new; \ } else { \ kfree(new); \ rpdev->member = NULL; \ } \ device_unlock(dev); \ \ kfree(old); \ \ return sz; \ } \ static ssize_t \ field##_show(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \ \ return sprintf(buf, "%s\n", rpdev->member); \ } \ static DEVICE_ATTR_RW(field) /* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */ rpmsg_show_attr(name, id.name, "%s\n"); rpmsg_show_attr(src, src, "0x%x\n"); rpmsg_show_attr(dst, dst, "0x%x\n"); rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n"); rpmsg_string_attr(driver_override, driver_override); static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); ssize_t len; len = of_device_modalias(dev, buf, PAGE_SIZE); if (len != -ENODEV) return len; return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name); } static DEVICE_ATTR_RO(modalias); static struct attribute *rpmsg_dev_attrs[] = { &dev_attr_name.attr, &dev_attr_modalias.attr, &dev_attr_dst.attr, &dev_attr_src.attr, &dev_attr_announce.attr, &dev_attr_driver_override.attr, NULL, }; ATTRIBUTE_GROUPS(rpmsg_dev); /* rpmsg devices and drivers are matched using the service name */ static inline int rpmsg_id_match(const struct rpmsg_device *rpdev, const struct rpmsg_device_id *id) { return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0; } /* match rpmsg channel and rpmsg driver */ static int rpmsg_dev_match(struct device *dev, struct device_driver *drv) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv); const struct rpmsg_device_id *ids = rpdrv->id_table; unsigned int i; if (rpdev->driver_override) return !strcmp(rpdev->driver_override, drv->name); if (ids) for (i = 0; ids[i].name[0]; i++) if (rpmsg_id_match(rpdev, &ids[i])) return 1; return of_driver_match_device(dev, drv); } static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); int ret; ret = of_device_uevent_modalias(dev, env); if (ret != -ENODEV) return ret; return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT, rpdev->id.name); } /* * when an rpmsg driver is probed with a channel, we seamlessly create * it an endpoint, binding its rx callback to a unique local rpmsg * address. * * if we need to, we also announce about this channel to the remote * processor (needed in case the driver is exposing an rpmsg service). */ static int rpmsg_dev_probe(struct device *dev) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); struct rpmsg_channel_info chinfo = {}; struct rpmsg_endpoint *ept = NULL; int err; err = dev_pm_domain_attach(dev, true); if (err) goto out; if (rpdrv->callback) { strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); chinfo.src = rpdev->src; chinfo.dst = RPMSG_ADDR_ANY; ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo); if (!ept) { dev_err(dev, "failed to create endpoint\n"); err = -ENOMEM; goto out; } rpdev->ept = ept; rpdev->src = ept->addr; } err = rpdrv->probe(rpdev); if (err) { dev_err(dev, "%s: failed: %d\n", __func__, err); if (ept) rpmsg_destroy_ept(ept); goto out; } if (ept && rpdev->ops->announce_create) err = rpdev->ops->announce_create(rpdev); out: return err; } static int rpmsg_dev_remove(struct device *dev) { struct rpmsg_device *rpdev = to_rpmsg_device(dev); struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); int err = 0; if (rpdev->ops->announce_destroy) err = rpdev->ops->announce_destroy(rpdev); if (rpdrv->remove) rpdrv->remove(rpdev); dev_pm_domain_detach(dev, true); if (rpdev->ept) rpmsg_destroy_ept(rpdev->ept); return err; } static struct bus_type rpmsg_bus = { .name = "rpmsg", .match = rpmsg_dev_match, .dev_groups = rpmsg_dev_groups, .uevent = rpmsg_uevent, .probe = rpmsg_dev_probe, .remove = rpmsg_dev_remove, }; int rpmsg_register_device(struct rpmsg_device *rpdev) { struct device *dev = &rpdev->dev; int ret; dev_set_name(&rpdev->dev, "%s.%s.%d.%d", dev_name(dev->parent), rpdev->id.name, rpdev->src, rpdev->dst); rpdev->dev.bus = &rpmsg_bus; ret = device_register(&rpdev->dev); if (ret) { dev_err(dev, "device_register failed: %d\n", ret); put_device(&rpdev->dev); } return ret; } EXPORT_SYMBOL(rpmsg_register_device); /* * find an existing channel using its name + address properties, * and destroy it */ int rpmsg_unregister_device(struct device *parent, struct rpmsg_channel_info *chinfo) { struct device *dev; dev = rpmsg_find_device(parent, chinfo); if (!dev) return -EINVAL; device_unregister(dev); put_device(dev); return 0; } EXPORT_SYMBOL(rpmsg_unregister_device); /** * __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus * @rpdrv: pointer to a struct rpmsg_driver * @owner: owning module/driver * * Returns 0 on success, and an appropriate error value on failure. */ int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner) { rpdrv->drv.bus = &rpmsg_bus; rpdrv->drv.owner = owner; return driver_register(&rpdrv->drv); } EXPORT_SYMBOL(__register_rpmsg_driver); /** * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus * @rpdrv: pointer to a struct rpmsg_driver * * Returns 0 on success, and an appropriate error value on failure. */ void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv) { driver_unregister(&rpdrv->drv); } EXPORT_SYMBOL(unregister_rpmsg_driver); static int __init rpmsg_init(void) { int ret; ret = bus_register(&rpmsg_bus); if (ret) pr_err("failed to register rpmsg bus: %d\n", ret); return ret; } postcore_initcall(rpmsg_init); static void __exit rpmsg_fini(void) { bus_unregister(&rpmsg_bus); } module_exit(rpmsg_fini); MODULE_DESCRIPTION("remote processor messaging bus"); MODULE_LICENSE("GPL v2");