linux/include/linux/rpmsg.h
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   1/*
   2 * Remote processor messaging
   3 *
   4 * Copyright (C) 2011 Texas Instruments, Inc.
   5 * Copyright (C) 2011 Google, Inc.
   6 * All rights reserved.
   7 *
   8 * Redistribution and use in source and binary forms, with or without
   9 * modification, are permitted provided that the following conditions
  10 * are met:
  11 *
  12 * * Redistributions of source code must retain the above copyright
  13 *   notice, this list of conditions and the following disclaimer.
  14 * * Redistributions in binary form must reproduce the above copyright
  15 *   notice, this list of conditions and the following disclaimer in
  16 *   the documentation and/or other materials provided with the
  17 *   distribution.
  18 * * Neither the name Texas Instruments nor the names of its
  19 *   contributors may be used to endorse or promote products derived
  20 *   from this software without specific prior written permission.
  21 *
  22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33 */
  34
  35#ifndef _LINUX_RPMSG_H
  36#define _LINUX_RPMSG_H
  37
  38#include <linux/types.h>
  39#include <linux/device.h>
  40#include <linux/mod_devicetable.h>
  41#include <linux/kref.h>
  42#include <linux/mutex.h>
  43
  44/* The feature bitmap for virtio rpmsg */
  45#define VIRTIO_RPMSG_F_NS       0 /* RP supports name service notifications */
  46
  47/**
  48 * struct rpmsg_hdr - common header for all rpmsg messages
  49 * @src: source address
  50 * @dst: destination address
  51 * @reserved: reserved for future use
  52 * @len: length of payload (in bytes)
  53 * @flags: message flags
  54 * @data: @len bytes of message payload data
  55 *
  56 * Every message sent(/received) on the rpmsg bus begins with this header.
  57 */
  58struct rpmsg_hdr {
  59        u32 src;
  60        u32 dst;
  61        u32 reserved;
  62        u16 len;
  63        u16 flags;
  64        u8 data[0];
  65} __packed;
  66
  67/**
  68 * struct rpmsg_ns_msg - dynamic name service announcement message
  69 * @name: name of remote service that is published
  70 * @addr: address of remote service that is published
  71 * @flags: indicates whether service is created or destroyed
  72 *
  73 * This message is sent across to publish a new service, or announce
  74 * about its removal. When we receive these messages, an appropriate
  75 * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
  76 * or ->remove() handler of the appropriate rpmsg driver will be invoked
  77 * (if/as-soon-as one is registered).
  78 */
  79struct rpmsg_ns_msg {
  80        char name[RPMSG_NAME_SIZE];
  81        u32 addr;
  82        u32 flags;
  83} __packed;
  84
  85/**
  86 * enum rpmsg_ns_flags - dynamic name service announcement flags
  87 *
  88 * @RPMSG_NS_CREATE: a new remote service was just created
  89 * @RPMSG_NS_DESTROY: a known remote service was just destroyed
  90 */
  91enum rpmsg_ns_flags {
  92        RPMSG_NS_CREATE         = 0,
  93        RPMSG_NS_DESTROY        = 1,
  94};
  95
  96#define RPMSG_ADDR_ANY          0xFFFFFFFF
  97
  98struct virtproc_info;
  99
 100/**
 101 * rpmsg_channel - devices that belong to the rpmsg bus are called channels
 102 * @vrp: the remote processor this channel belongs to
 103 * @dev: the device struct
 104 * @id: device id (used to match between rpmsg drivers and devices)
 105 * @src: local address
 106 * @dst: destination address
 107 * @ept: the rpmsg endpoint of this channel
 108 * @announce: if set, rpmsg will announce the creation/removal of this channel
 109 */
 110struct rpmsg_channel {
 111        struct virtproc_info *vrp;
 112        struct device dev;
 113        struct rpmsg_device_id id;
 114        u32 src;
 115        u32 dst;
 116        struct rpmsg_endpoint *ept;
 117        bool announce;
 118};
 119
 120typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
 121
 122/**
 123 * struct rpmsg_endpoint - binds a local rpmsg address to its user
 124 * @rpdev: rpmsg channel device
 125 * @refcount: when this drops to zero, the ept is deallocated
 126 * @cb: rx callback handler
 127 * @cb_lock: must be taken before accessing/changing @cb
 128 * @addr: local rpmsg address
 129 * @priv: private data for the driver's use
 130 *
 131 * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
 132 * it binds an rpmsg address with an rx callback handler.
 133 *
 134 * Simple rpmsg drivers shouldn't use this struct directly, because
 135 * things just work: every rpmsg driver provides an rx callback upon
 136 * registering to the bus, and that callback is then bound to its rpmsg
 137 * address when the driver is probed. When relevant inbound messages arrive
 138 * (i.e. messages which their dst address equals to the src address of
 139 * the rpmsg channel), the driver's handler is invoked to process it.
 140 *
 141 * More complicated drivers though, that do need to allocate additional rpmsg
 142 * addresses, and bind them to different rx callbacks, must explicitly
 143 * create additional endpoints by themselves (see rpmsg_create_ept()).
 144 */
 145struct rpmsg_endpoint {
 146        struct rpmsg_channel *rpdev;
 147        struct kref refcount;
 148        rpmsg_rx_cb_t cb;
 149        struct mutex cb_lock;
 150        u32 addr;
 151        void *priv;
 152};
 153
 154/**
 155 * struct rpmsg_driver - rpmsg driver struct
 156 * @drv: underlying device driver
 157 * @id_table: rpmsg ids serviced by this driver
 158 * @probe: invoked when a matching rpmsg channel (i.e. device) is found
 159 * @remove: invoked when the rpmsg channel is removed
 160 * @callback: invoked when an inbound message is received on the channel
 161 */
 162struct rpmsg_driver {
 163        struct device_driver drv;
 164        const struct rpmsg_device_id *id_table;
 165        int (*probe)(struct rpmsg_channel *dev);
 166        void (*remove)(struct rpmsg_channel *dev);
 167        void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
 168};
 169
 170int register_rpmsg_device(struct rpmsg_channel *dev);
 171void unregister_rpmsg_device(struct rpmsg_channel *dev);
 172int register_rpmsg_driver(struct rpmsg_driver *drv);
 173void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 174void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 175struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
 176                                rpmsg_rx_cb_t cb, void *priv, u32 addr);
 177int
 178rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
 179
 180/**
 181 * rpmsg_send() - send a message across to the remote processor
 182 * @rpdev: the rpmsg channel
 183 * @data: payload of message
 184 * @len: length of payload
 185 *
 186 * This function sends @data of length @len on the @rpdev channel.
 187 * The message will be sent to the remote processor which the @rpdev
 188 * channel belongs to, using @rpdev's source and destination addresses.
 189 * In case there are no TX buffers available, the function will block until
 190 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 191 * happens, -ERESTARTSYS is returned.
 192 *
 193 * Can only be called from process context (for now).
 194 *
 195 * Returns 0 on success and an appropriate error value on failure.
 196 */
 197static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
 198{
 199        u32 src = rpdev->src, dst = rpdev->dst;
 200
 201        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 202}
 203
 204/**
 205 * rpmsg_sendto() - send a message across to the remote processor, specify dst
 206 * @rpdev: the rpmsg channel
 207 * @data: payload of message
 208 * @len: length of payload
 209 * @dst: destination address
 210 *
 211 * This function sends @data of length @len to the remote @dst address.
 212 * The message will be sent to the remote processor which the @rpdev
 213 * channel belongs to, using @rpdev's source address.
 214 * In case there are no TX buffers available, the function will block until
 215 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 216 * happens, -ERESTARTSYS is returned.
 217 *
 218 * Can only be called from process context (for now).
 219 *
 220 * Returns 0 on success and an appropriate error value on failure.
 221 */
 222static inline
 223int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
 224{
 225        u32 src = rpdev->src;
 226
 227        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 228}
 229
 230/**
 231 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 232 * @rpdev: the rpmsg channel
 233 * @src: source address
 234 * @dst: destination address
 235 * @data: payload of message
 236 * @len: length of payload
 237 *
 238 * This function sends @data of length @len to the remote @dst address,
 239 * and uses @src as the source address.
 240 * The message will be sent to the remote processor which the @rpdev
 241 * channel belongs to.
 242 * In case there are no TX buffers available, the function will block until
 243 * one becomes available, or a timeout of 15 seconds elapses. When the latter
 244 * happens, -ERESTARTSYS is returned.
 245 *
 246 * Can only be called from process context (for now).
 247 *
 248 * Returns 0 on success and an appropriate error value on failure.
 249 */
 250static inline
 251int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
 252                                                        void *data, int len)
 253{
 254        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 255}
 256
 257/**
 258 * rpmsg_send() - send a message across to the remote processor
 259 * @rpdev: the rpmsg channel
 260 * @data: payload of message
 261 * @len: length of payload
 262 *
 263 * This function sends @data of length @len on the @rpdev channel.
 264 * The message will be sent to the remote processor which the @rpdev
 265 * channel belongs to, using @rpdev's source and destination addresses.
 266 * In case there are no TX buffers available, the function will immediately
 267 * return -ENOMEM without waiting until one becomes available.
 268 *
 269 * Can only be called from process context (for now).
 270 *
 271 * Returns 0 on success and an appropriate error value on failure.
 272 */
 273static inline
 274int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
 275{
 276        u32 src = rpdev->src, dst = rpdev->dst;
 277
 278        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 279}
 280
 281/**
 282 * rpmsg_sendto() - send a message across to the remote processor, specify dst
 283 * @rpdev: the rpmsg channel
 284 * @data: payload of message
 285 * @len: length of payload
 286 * @dst: destination address
 287 *
 288 * This function sends @data of length @len to the remote @dst address.
 289 * The message will be sent to the remote processor which the @rpdev
 290 * channel belongs to, using @rpdev's source address.
 291 * In case there are no TX buffers available, the function will immediately
 292 * return -ENOMEM without waiting until one becomes available.
 293 *
 294 * Can only be called from process context (for now).
 295 *
 296 * Returns 0 on success and an appropriate error value on failure.
 297 */
 298static inline
 299int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
 300{
 301        u32 src = rpdev->src;
 302
 303        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 304}
 305
 306/**
 307 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 308 * @rpdev: the rpmsg channel
 309 * @src: source address
 310 * @dst: destination address
 311 * @data: payload of message
 312 * @len: length of payload
 313 *
 314 * This function sends @data of length @len to the remote @dst address,
 315 * and uses @src as the source address.
 316 * The message will be sent to the remote processor which the @rpdev
 317 * channel belongs to.
 318 * In case there are no TX buffers available, the function will immediately
 319 * return -ENOMEM without waiting until one becomes available.
 320 *
 321 * Can only be called from process context (for now).
 322 *
 323 * Returns 0 on success and an appropriate error value on failure.
 324 */
 325static inline
 326int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
 327                                                        void *data, int len)
 328{
 329        return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 330}
 331
 332#endif /* _LINUX_RPMSG_H */
 333
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