include/linux/rpmsg.h

   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  */
  58 struct 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  */
  79 struct 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  */
  91 enum rpmsg_ns_flags {
  92         RPMSG_NS_CREATE         = 0,
  93         RPMSG_NS_DESTROY        = 1,
  94 };
  95
  96 #define RPMSG_ADDR_ANY          0xFFFFFFFF
  97
  98 struct 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  */
 110 struct 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
 120 typedef 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  */
 145 struct 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  */
 162 struct 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
 170 int register_rpmsg_device(struct rpmsg_channel *dev);
 171 void unregister_rpmsg_device(struct rpmsg_channel *dev);
 172 int register_rpmsg_driver(struct rpmsg_driver *drv);
 173 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 174 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 175 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
 176                                 rpmsg_rx_cb_t cb, void *priv, u32 addr);
 177 int
 178 rpmsg_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  */
 197 static 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  */
 222 static inline
 223 int 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  */
 250 static inline
 251 int 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  */
 273 static inline
 274 int 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  */
 298 static inline
 299 int 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  */
 325 static inline
 326 int 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 */