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
  42 /* The feature bitmap for virtio rpmsg */
  43 #define VIRTIO_RPMSG_F_NS       0 /* RP supports name service notifications */
  44
  45 /**
  46  * struct rpmsg_hdr - common header for all rpmsg messages
  47  * @src: source address
  48  * @dst: destination address
  49  * @reserved: reserved for future use
  50  * @len: length of payload (in bytes)
  51  * @flags: message flags
  52  * @data: @len bytes of message payload data
  53  *
  54  * Every message sent(/received) on the rpmsg bus begins with this header.
  55  */
  56 struct rpmsg_hdr {
  57         u32 src;
  58         u32 dst;
  59         u32 reserved;
  60         u16 len;
  61         u16 flags;
  62         u8 data[0];
  63 } __packed;
  64
  65 /**
  66  * struct rpmsg_ns_msg - dynamic name service announcement message
  67  * @name: name of remote service that is published
  68  * @addr: address of remote service that is published
  69  * @flags: indicates whether service is created or destroyed
  70  *
  71  * This message is sent across to publish a new service, or announce
  72  * about its removal. When we receive these messages, an appropriate
  73  * rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
  74  * or ->remove() handler of the appropriate rpmsg driver will be invoked
  75  * (if/as-soon-as one is registered).
  76  */
  77 struct rpmsg_ns_msg {
  78         char name[RPMSG_NAME_SIZE];
  79         u32 addr;
  80         u32 flags;
  81 } __packed;
  82
  83 /**
  84  * enum rpmsg_ns_flags - dynamic name service announcement flags
  85  *
  86  * @RPMSG_NS_CREATE: a new remote service was just created
  87  * @RPMSG_NS_DESTROY: a known remote service was just destroyed
  88  */
  89 enum rpmsg_ns_flags {
  90         RPMSG_NS_CREATE         = 0,
  91         RPMSG_NS_DESTROY        = 1,
  92 };
  93
  94 #define RPMSG_ADDR_ANY          0xFFFFFFFF
  95
  96 struct virtproc_info;
  97
  98 /**
  99  * rpmsg_channel - devices that belong to the rpmsg bus are called channels
 100  * @vrp: the remote processor this channel belongs to
 101  * @dev: the device struct
 102  * @id: device id (used to match between rpmsg drivers and devices)
 103  * @src: local address
 104  * @dst: destination address
 105  * @ept: the rpmsg endpoint of this channel
 106  * @announce: if set, rpmsg will announce the creation/removal of this channel
 107  */
 108 struct rpmsg_channel {
 109         struct virtproc_info *vrp;
 110         struct device dev;
 111         struct rpmsg_device_id id;
 112         u32 src;
 113         u32 dst;
 114         struct rpmsg_endpoint *ept;
 115         bool announce;
 116 };
 117
 118 typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
 119
 120 /**
 121  * struct rpmsg_endpoint - binds a local rpmsg address to its user
 122  * @rpdev: rpmsg channel device
 123  * @cb: rx callback handler
 124  * @addr: local rpmsg address
 125  * @priv: private data for the driver's use
 126  *
 127  * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
 128  * it binds an rpmsg address with an rx callback handler.
 129  *
 130  * Simple rpmsg drivers shouldn't use this struct directly, because
 131  * things just work: every rpmsg driver provides an rx callback upon
 132  * registering to the bus, and that callback is then bound to its rpmsg
 133  * address when the driver is probed. When relevant inbound messages arrive
 134  * (i.e. messages which their dst address equals to the src address of
 135  * the rpmsg channel), the driver's handler is invoked to process it.
 136  *
 137  * More complicated drivers though, that do need to allocate additional rpmsg
 138  * addresses, and bind them to different rx callbacks, must explicitly
 139  * create additional endpoints by themselves (see rpmsg_create_ept()).
 140  */
 141 struct rpmsg_endpoint {
 142         struct rpmsg_channel *rpdev;
 143         rpmsg_rx_cb_t cb;
 144         u32 addr;
 145         void *priv;
 146 };
 147
 148 /**
 149  * struct rpmsg_driver - rpmsg driver struct
 150  * @drv: underlying device driver
 151  * @id_table: rpmsg ids serviced by this driver
 152  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
 153  * @remove: invoked when the rpmsg channel is removed
 154  * @callback: invoked when an inbound message is received on the channel
 155  */
 156 struct rpmsg_driver {
 157         struct device_driver drv;
 158         const struct rpmsg_device_id *id_table;
 159         int (*probe)(struct rpmsg_channel *dev);
 160         void (*remove)(struct rpmsg_channel *dev);
 161         void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
 162 };
 163
 164 int register_rpmsg_device(struct rpmsg_channel *dev);
 165 void unregister_rpmsg_device(struct rpmsg_channel *dev);
 166 int register_rpmsg_driver(struct rpmsg_driver *drv);
 167 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 168 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 169 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
 170                                 rpmsg_rx_cb_t cb, void *priv, u32 addr);
 171 int
 172 rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
 173
 174 /**
 175  * rpmsg_send() - send a message across to the remote processor
 176  * @rpdev: the rpmsg channel
 177  * @data: payload of message
 178  * @len: length of payload
 179  *
 180  * This function sends @data of length @len on the @rpdev channel.
 181  * The message will be sent to the remote processor which the @rpdev
 182  * channel belongs to, using @rpdev's source and destination addresses.
 183  * In case there are no TX buffers available, the function will block until
 184  * one becomes available, or a timeout of 15 seconds elapses. When the latter
 185  * happens, -ERESTARTSYS is returned.
 186  *
 187  * Can only be called from process context (for now).
 188  *
 189  * Returns 0 on success and an appropriate error value on failure.
 190  */
 191 static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
 192 {
 193         u32 src = rpdev->src, dst = rpdev->dst;
 194
 195         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 196 }
 197
 198 /**
 199  * rpmsg_sendto() - send a message across to the remote processor, specify dst
 200  * @rpdev: the rpmsg channel
 201  * @data: payload of message
 202  * @len: length of payload
 203  * @dst: destination address
 204  *
 205  * This function sends @data of length @len to the remote @dst address.
 206  * The message will be sent to the remote processor which the @rpdev
 207  * channel belongs to, using @rpdev's source address.
 208  * In case there are no TX buffers available, the function will block until
 209  * one becomes available, or a timeout of 15 seconds elapses. When the latter
 210  * happens, -ERESTARTSYS is returned.
 211  *
 212  * Can only be called from process context (for now).
 213  *
 214  * Returns 0 on success and an appropriate error value on failure.
 215  */
 216 static inline
 217 int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
 218 {
 219         u32 src = rpdev->src;
 220
 221         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 222 }
 223
 224 /**
 225  * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 226  * @rpdev: the rpmsg channel
 227  * @src: source address
 228  * @dst: destination address
 229  * @data: payload of message
 230  * @len: length of payload
 231  *
 232  * This function sends @data of length @len to the remote @dst address,
 233  * and uses @src as the source address.
 234  * The message will be sent to the remote processor which the @rpdev
 235  * channel belongs to.
 236  * In case there are no TX buffers available, the function will block until
 237  * one becomes available, or a timeout of 15 seconds elapses. When the latter
 238  * happens, -ERESTARTSYS is returned.
 239  *
 240  * Can only be called from process context (for now).
 241  *
 242  * Returns 0 on success and an appropriate error value on failure.
 243  */
 244 static inline
 245 int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
 246                                                         void *data, int len)
 247 {
 248         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
 249 }
 250
 251 /**
 252  * rpmsg_send() - send a message across to the remote processor
 253  * @rpdev: the rpmsg channel
 254  * @data: payload of message
 255  * @len: length of payload
 256  *
 257  * This function sends @data of length @len on the @rpdev channel.
 258  * The message will be sent to the remote processor which the @rpdev
 259  * channel belongs to, using @rpdev's source and destination addresses.
 260  * In case there are no TX buffers available, the function will immediately
 261  * return -ENOMEM without waiting until one becomes available.
 262  *
 263  * Can only be called from process context (for now).
 264  *
 265  * Returns 0 on success and an appropriate error value on failure.
 266  */
 267 static inline
 268 int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
 269 {
 270         u32 src = rpdev->src, dst = rpdev->dst;
 271
 272         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 273 }
 274
 275 /**
 276  * rpmsg_sendto() - send a message across to the remote processor, specify dst
 277  * @rpdev: the rpmsg channel
 278  * @data: payload of message
 279  * @len: length of payload
 280  * @dst: destination address
 281  *
 282  * This function sends @data of length @len to the remote @dst address.
 283  * The message will be sent to the remote processor which the @rpdev
 284  * channel belongs to, using @rpdev's source address.
 285  * In case there are no TX buffers available, the function will immediately
 286  * return -ENOMEM without waiting until one becomes available.
 287  *
 288  * Can only be called from process context (for now).
 289  *
 290  * Returns 0 on success and an appropriate error value on failure.
 291  */
 292 static inline
 293 int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
 294 {
 295         u32 src = rpdev->src;
 296
 297         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 298 }
 299
 300 /**
 301  * rpmsg_send_offchannel() - send a message using explicit src/dst addresses
 302  * @rpdev: the rpmsg channel
 303  * @src: source address
 304  * @dst: destination address
 305  * @data: payload of message
 306  * @len: length of payload
 307  *
 308  * This function sends @data of length @len to the remote @dst address,
 309  * and uses @src as the source address.
 310  * The message will be sent to the remote processor which the @rpdev
 311  * channel belongs to.
 312  * In case there are no TX buffers available, the function will immediately
 313  * return -ENOMEM without waiting until one becomes available.
 314  *
 315  * Can only be called from process context (for now).
 316  *
 317  * Returns 0 on success and an appropriate error value on failure.
 318  */
 319 static inline
 320 int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
 321                                                         void *data, int len)
 322 {
 323         return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
 324 }
 325
 326 #endif /* _LINUX_RPMSG_H */