diff options
Diffstat (limited to 'drivers/rpmsg/rpmsg_core.c')
| -rw-r--r-- | drivers/rpmsg/rpmsg_core.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c new file mode 100644 index 000000000..65834153b --- /dev/null +++ b/drivers/rpmsg/rpmsg_core.c @@ -0,0 +1,615 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * remote processor messaging bus + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Copyright (C) 2011 Google, Inc. + * + * Ohad Ben-Cohen <ohad@wizery.com> + * Brian Swetland <swetland@google.com> + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/rpmsg.h> +#include <linux/of_device.h> +#include <linux/pm_domain.h> +#include <linux/slab.h> + +#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 do 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_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 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_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 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_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 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); + goto destroy_ept; + } + + if (ept && rpdev->ops->announce_create) { + err = rpdev->ops->announce_create(rpdev); + if (err) { + dev_err(dev, "failed to announce creation\n"); + goto remove_rpdev; + } + } + + return 0; + +remove_rpdev: + if (rpdrv->remove) + rpdrv->remove(rpdev); +destroy_ept: + if (ept) + rpmsg_destroy_ept(ept); +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); + + 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"); |