/*
* Remote processor messaging
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name Texas Instruments nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _LINUX_RPMSG_H
#define _LINUX_RPMSG_H
#include <linux/types.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/kref.h>
#include <linux/mutex.h>
/* The feature bitmap for virtio rpmsg */
#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
/**
* struct rpmsg_hdr - common header for all rpmsg messages
* @src: source address
* @dst: destination address
* @reserved: reserved for future use
* @len: length of payload (in bytes)
* @flags: message flags
* @data: @len bytes of message payload data
*
* Every message sent(/received) on the rpmsg bus begins with this header.
*/
struct rpmsg_hdr {
u32 src;
u32 dst;
u32 reserved;
u16 len;
u16 flags;
u8 data[0];
} __packed;
/**
* struct rpmsg_ns_msg - dynamic name service announcement message
* @name: name of remote service that is published
* @addr: address of remote service that is published
* @flags: indicates whether service is created or destroyed
*
* This message is sent across to publish a new service, or announce
* about its removal. When we receive these messages, an appropriate
* rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
* or ->remove() handler of the appropriate rpmsg driver will be invoked
* (if/as-soon-as one is registered).
*/
struct rpmsg_ns_msg {
char name[RPMSG_NAME_SIZE];
u32 addr;
u32 flags;
} __packed;
/**
* enum rpmsg_ns_flags - dynamic name service announcement flags
*
* @RPMSG_NS_CREATE: a new remote service was just created
* @RPMSG_NS_DESTROY: a known remote service was just destroyed
*/
enum rpmsg_ns_flags {
RPMSG_NS_CREATE = 0,
RPMSG_NS_DESTROY = 1,
};
#define RPMSG_ADDR_ANY 0xFFFFFFFF
struct virtproc_info;
/**
* rpmsg_channel - devices that belong to the rpmsg bus are called channels
* @vrp: the remote processor this channel belongs to
* @dev: the device struct
* @id: device id (used to match between rpmsg drivers and devices)
* @src: local address
* @dst: destination address
* @ept: the rpmsg endpoint of this channel
* @announce: if set, rpmsg will announce the creation/removal of this channel
*/
struct rpmsg_channel {
struct virtproc_info *vrp;
struct device dev;
struct rpmsg_device_id id;
u32 src;
u32 dst;
struct rpmsg_endpoint *ept;
bool announce;
};
typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
/**
* struct rpmsg_endpoint - binds a local rpmsg address to its user
* @rpdev: rpmsg channel device
* @refcount: when this drops to zero, the ept is deallocated
* @cb: rx callback handler
* @cb_lock: must be taken before accessing/changing @cb
* @addr: local rpmsg address
* @priv: private data for the driver's use
*
* In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
* it binds an rpmsg address with an rx callback handler.
*
* Simple rpmsg drivers shouldn't use this struct directly, because
* things just work: every rpmsg driver provides an rx callback upon
* registering to the bus, and that callback is then bound to its rpmsg
* address when the driver is probed. When relevant inbound messages arrive
* (i.e. messages which their dst address equals to the src address of
* the rpmsg channel), the driver's handler is invoked to process it.
*
* More complicated drivers though, that do need to allocate additional rpmsg
* addresses, and bind them to different rx callbacks, must explicitly
* create additional endpoints by themselves (see rpmsg_create_ept()).
*/
struct rpmsg_endpoint {
struct rpmsg_channel *rpdev;
struct kref refcount;
rpmsg_rx_cb_t cb;
struct mutex cb_lock;
u32 addr;
void *priv;
};
/**
* struct rpmsg_driver - rpmsg driver struct
* @drv: underlying device driver
* @id_table: rpmsg ids serviced by this driver
* @probe: invoked when a matching rpmsg channel (i.e. device) is found
* @remove: invoked when the rpmsg channel is removed
* @callback: invoked when an inbound message is received on the channel
*/
struct rpmsg_driver {
struct device_driver drv;
const struct rpmsg_device_id *id_table;
int (*probe)(struct rpmsg_channel *dev);
void (*remove)(struct rpmsg_channel *dev);
void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
};
int register_rpmsg_device(struct rpmsg_channel *dev);
void unregister_rpmsg_device(struct rpmsg_channel *dev);
int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
void unregister_rpmsg_driver(struct rpmsg_driver *drv);
void rpmsg_destroy_ept(struct rpmsg_endpoint *);
struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
rpmsg_rx_cb_t cb, void *priv, u32 addr);
int
rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
/* use a macro to avoid include chaining to get THIS_MODULE */
#define register_rpmsg_driver(drv) \
__register_rpmsg_driver(drv, THIS_MODULE)
/**
* module_rpmsg_driver() - Helper macro for registering an rpmsg driver
* @__rpmsg_driver: rpmsg_driver struct
*
* Helper macro for rpmsg drivers which do not do anything special in module
* init/exit. This eliminates a lot of boilerplate. Each module may only
* use this macro once, and calling it replaces module_init() and module_exit()
*/
#define module_rpmsg_driver(__rpmsg_driver) \
module_driver(__rpmsg_driver, register_rpmsg_driver, \
unregister_rpmsg_driver)
/**
* rpmsg_send() - send a message across to the remote processor
* @rpdev: the rpmsg channel
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len on the @rpdev channel.
* The message will be sent to the remote processor which the @rpdev
* channel belongs to, using @rpdev's source and 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.
*/
static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
{
u32 src = rpdev->src, dst = rpdev->dst;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
/**
* rpmsg_sendto() - send a message across to the remote processor, specify dst
* @rpdev: the rpmsg channel
* @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 @rpdev
* channel belongs to, using @rpdev's source address.
* 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.
*/
static inline
int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
{
u32 src = rpdev->src;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
/**
* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
* @rpdev: the rpmsg channel
* @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 @rpdev
* channel 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.
*/
static inline
int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
void *data, int len)
{
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
/**
* rpmsg_send() - send a message across to the remote processor
* @rpdev: the rpmsg channel
* @data: payload of message
* @len: length of payload
*
* This function sends @data of length @len on the @rpdev channel.
* The message will be sent to the remote processor which the @rpdev
* channel belongs to, using @rpdev's source and destination addresses.
* 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.
*/
static inline
int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
{
u32 src = rpdev->src, dst = rpdev->dst;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
/**
* rpmsg_sendto() - send a message across to the remote processor, specify dst
* @rpdev: the rpmsg channel
* @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 @rpdev
* channel belongs to, using @rpdev's source address.
* 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.
*/
static inline
int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
{
u32 src = rpdev->src;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
/**
* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
* @rpdev: the rpmsg channel
* @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 @rpdev
* channel 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.
*/
static inline
int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
void *data, int len)
{
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
#endif /* _LINUX_RPMSG_H */
