// 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);
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);
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");
