499 lines
15 KiB
C
499 lines
15 KiB
C
/*
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* remote processor messaging bus
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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* Copyright (C) 2011 Google, Inc.
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*
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* Ohad Ben-Cohen <ohad@wizery.com>
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* Brian Swetland <swetland@google.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) "%s: " fmt, __func__
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/rpmsg.h>
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#include <linux/of_device.h>
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#include <linux/slab.h>
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#include "rpmsg_internal.h"
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/**
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* rpmsg_create_ept() - create a new rpmsg_endpoint
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* @rpdev: rpmsg channel device
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* @cb: rx callback handler
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* @priv: private data for the driver's use
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* @chinfo: channel_info with the local rpmsg address to bind with @cb
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*
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* Every rpmsg address in the system is bound to an rx callback (so when
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* inbound messages arrive, they are dispatched by the rpmsg bus using the
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* appropriate callback handler) by means of an rpmsg_endpoint struct.
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*
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* This function allows drivers to create such an endpoint, and by that,
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* bind a callback, and possibly some private data too, to an rpmsg address
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* (either one that is known in advance, or one that will be dynamically
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* assigned for them).
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*
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* Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
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* is already created for them when they are probed by the rpmsg bus
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* (using the rx callback provided when they registered to the rpmsg bus).
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*
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* So things should just work for simple drivers: they already have an
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* endpoint, their rx callback is bound to their rpmsg address, and when
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* relevant inbound messages arrive (i.e. messages which their dst address
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* equals to the src address of their rpmsg channel), the driver's handler
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* is invoked to process it.
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*
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* That said, more complicated drivers might do need to allocate
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* additional rpmsg addresses, and bind them to different rx callbacks.
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* To accomplish that, those drivers need to call this function.
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*
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* Drivers should provide their @rpdev channel (so the new endpoint would belong
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* to the same remote processor their channel belongs to), an rx callback
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* function, an optional private data (which is provided back when the
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* rx callback is invoked), and an address they want to bind with the
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* callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
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* dynamically assign them an available rpmsg address (drivers should have
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* a very good reason why not to always use RPMSG_ADDR_ANY here).
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*
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* Returns a pointer to the endpoint on success, or NULL on error.
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*/
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struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
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rpmsg_rx_cb_t cb, void *priv,
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struct rpmsg_channel_info chinfo)
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{
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return rpdev->ops->create_ept(rpdev, cb, priv, chinfo);
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}
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EXPORT_SYMBOL(rpmsg_create_ept);
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/**
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* rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
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* @ept: endpoing to destroy
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*
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* Should be used by drivers to destroy an rpmsg endpoint previously
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* created with rpmsg_create_ept().
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*/
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void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
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{
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ept->ops->destroy_ept(ept);
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}
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EXPORT_SYMBOL(rpmsg_destroy_ept);
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/**
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* rpmsg_send() - send a message across to the remote processor
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* @ept: the rpmsg endpoint
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len on the @ept endpoint.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to, using @ept's address and its associated rpmsg
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* device destination addresses.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
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{
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return ept->ops->send(ept, data, len);
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}
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EXPORT_SYMBOL(rpmsg_send);
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/**
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* rpmsg_sendto() - send a message across to the remote processor, specify dst
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* @ept: the rpmsg endpoint
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* @data: payload of message
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* @len: length of payload
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* @dst: destination address
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*
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* This function sends @data of length @len to the remote @dst address.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to, using @ept's address as source.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
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{
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return ept->ops->sendto(ept, data, len, dst);
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}
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EXPORT_SYMBOL(rpmsg_sendto);
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/**
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* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
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* @ept: the rpmsg endpoint
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* @src: source address
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* @dst: destination address
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len to the remote @dst address,
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* and uses @src as the source address.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
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void *data, int len)
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{
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return ept->ops->send_offchannel(ept, src, dst, data, len);
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}
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EXPORT_SYMBOL(rpmsg_send_offchannel);
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/**
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* rpmsg_send() - send a message across to the remote processor
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* @ept: the rpmsg endpoint
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len on the @ept endpoint.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to, using @ept's address as source and its associated
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* rpdev's address as destination.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
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{
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return ept->ops->trysend(ept, data, len);
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}
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EXPORT_SYMBOL(rpmsg_trysend);
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/**
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* rpmsg_sendto() - send a message across to the remote processor, specify dst
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* @ept: the rpmsg endpoint
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* @data: payload of message
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* @len: length of payload
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* @dst: destination address
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*
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* This function sends @data of length @len to the remote @dst address.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to, using @ept's address as source.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
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{
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return ept->ops->trysendto(ept, data, len, dst);
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}
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EXPORT_SYMBOL(rpmsg_trysendto);
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/**
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* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
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* @ept: the rpmsg endpoint
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* @src: source address
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* @dst: destination address
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len to the remote @dst address,
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* and uses @src as the source address.
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* The message will be sent to the remote processor which the @ept
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* endpoint belongs to.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
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void *data, int len)
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{
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return ept->ops->trysend_offchannel(ept, src, dst, data, len);
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}
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EXPORT_SYMBOL(rpmsg_trysend_offchannel);
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/*
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* match an rpmsg channel with a channel info struct.
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* this is used to make sure we're not creating rpmsg devices for channels
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* that already exist.
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*/
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static int rpmsg_device_match(struct device *dev, void *data)
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{
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struct rpmsg_channel_info *chinfo = data;
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
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return 0;
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if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
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return 0;
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if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
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return 0;
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/* found a match ! */
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return 1;
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}
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struct device *rpmsg_find_device(struct device *parent,
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struct rpmsg_channel_info *chinfo)
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{
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return device_find_child(parent, chinfo, rpmsg_device_match);
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}
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EXPORT_SYMBOL(rpmsg_find_device);
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/* sysfs show configuration fields */
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#define rpmsg_show_attr(field, path, format_string) \
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static ssize_t \
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field##_show(struct device *dev, \
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struct device_attribute *attr, char *buf) \
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{ \
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struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
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\
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return sprintf(buf, format_string, rpdev->path); \
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}
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/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
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rpmsg_show_attr(name, id.name, "%s\n");
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rpmsg_show_attr(src, src, "0x%x\n");
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rpmsg_show_attr(dst, dst, "0x%x\n");
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rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
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static ssize_t modalias_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
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}
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static struct device_attribute rpmsg_dev_attrs[] = {
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__ATTR_RO(name),
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__ATTR_RO(modalias),
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__ATTR_RO(dst),
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__ATTR_RO(src),
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__ATTR_RO(announce),
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__ATTR_NULL
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};
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/* rpmsg devices and drivers are matched using the service name */
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static inline int rpmsg_id_match(const struct rpmsg_device *rpdev,
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const struct rpmsg_device_id *id)
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{
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return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
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}
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/* match rpmsg channel and rpmsg driver */
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static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
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const struct rpmsg_device_id *ids = rpdrv->id_table;
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unsigned int i;
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if (ids)
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for (i = 0; ids[i].name[0]; i++)
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if (rpmsg_id_match(rpdev, &ids[i]))
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return 1;
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return of_driver_match_device(dev, drv);
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}
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static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
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rpdev->id.name);
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}
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/*
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* when an rpmsg driver is probed with a channel, we seamlessly create
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* it an endpoint, binding its rx callback to a unique local rpmsg
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* address.
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*
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* if we need to, we also announce about this channel to the remote
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* processor (needed in case the driver is exposing an rpmsg service).
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*/
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static int rpmsg_dev_probe(struct device *dev)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
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struct rpmsg_channel_info chinfo = {};
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struct rpmsg_endpoint *ept;
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int err;
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strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
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chinfo.src = rpdev->src;
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chinfo.dst = RPMSG_ADDR_ANY;
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ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, chinfo);
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if (!ept) {
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dev_err(dev, "failed to create endpoint\n");
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err = -ENOMEM;
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goto out;
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}
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rpdev->ept = ept;
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rpdev->src = ept->addr;
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err = rpdrv->probe(rpdev);
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if (err) {
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dev_err(dev, "%s: failed: %d\n", __func__, err);
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rpmsg_destroy_ept(ept);
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goto out;
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}
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if (rpdev->ops->announce_create)
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err = rpdev->ops->announce_create(rpdev);
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out:
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return err;
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}
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static int rpmsg_dev_remove(struct device *dev)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
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int err = 0;
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if (rpdev->ops->announce_destroy)
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err = rpdev->ops->announce_destroy(rpdev);
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rpdrv->remove(rpdev);
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rpmsg_destroy_ept(rpdev->ept);
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return err;
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}
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static struct bus_type rpmsg_bus = {
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.name = "rpmsg",
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.match = rpmsg_dev_match,
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.dev_attrs = rpmsg_dev_attrs,
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.uevent = rpmsg_uevent,
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.probe = rpmsg_dev_probe,
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.remove = rpmsg_dev_remove,
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};
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static void rpmsg_release_device(struct device *dev)
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{
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struct rpmsg_device *rpdev = to_rpmsg_device(dev);
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kfree(rpdev);
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}
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int rpmsg_register_device(struct rpmsg_device *rpdev)
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{
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struct device *dev = &rpdev->dev;
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int ret;
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dev_set_name(&rpdev->dev, "%s.%s.%d.%d", dev_name(dev->parent),
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rpdev->id.name, rpdev->src, rpdev->dst);
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rpdev->dev.bus = &rpmsg_bus;
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rpdev->dev.release = rpmsg_release_device;
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ret = device_register(&rpdev->dev);
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if (ret) {
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dev_err(dev, "device_register failed: %d\n", ret);
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put_device(&rpdev->dev);
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}
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return ret;
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}
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EXPORT_SYMBOL(rpmsg_register_device);
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/*
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* find an existing channel using its name + address properties,
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* and destroy it
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*/
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int rpmsg_unregister_device(struct device *parent,
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struct rpmsg_channel_info *chinfo)
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{
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struct device *dev;
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dev = rpmsg_find_device(parent, chinfo);
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if (!dev)
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return -EINVAL;
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device_unregister(dev);
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put_device(dev);
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return 0;
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}
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EXPORT_SYMBOL(rpmsg_unregister_device);
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/**
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* __register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
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* @rpdrv: pointer to a struct rpmsg_driver
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* @owner: owning module/driver
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*
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* Returns 0 on success, and an appropriate error value on failure.
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*/
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int __register_rpmsg_driver(struct rpmsg_driver *rpdrv, struct module *owner)
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{
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rpdrv->drv.bus = &rpmsg_bus;
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rpdrv->drv.owner = owner;
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return driver_register(&rpdrv->drv);
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}
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EXPORT_SYMBOL(__register_rpmsg_driver);
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/**
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* unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
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* @rpdrv: pointer to a struct rpmsg_driver
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*
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* Returns 0 on success, and an appropriate error value on failure.
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*/
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void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
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{
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driver_unregister(&rpdrv->drv);
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}
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EXPORT_SYMBOL(unregister_rpmsg_driver);
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static int __init rpmsg_init(void)
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{
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int ret;
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ret = bus_register(&rpmsg_bus);
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if (ret)
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pr_err("failed to register rpmsg bus: %d\n", ret);
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return ret;
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}
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postcore_initcall(rpmsg_init);
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static void __exit rpmsg_fini(void)
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{
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bus_unregister(&rpmsg_bus);
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}
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module_exit(rpmsg_fini);
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MODULE_DESCRIPTION("remote processor messaging bus");
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MODULE_LICENSE("GPL v2");
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