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/err.h>
  41 #include <linux/mod_devicetable.h>
  42 #include <linux/kref.h>
  43 #include <linux/mutex.h>
  44 #include <linux/poll.h>
  45
  46 #define RPMSG_ADDR_ANY          0xFFFFFFFF
  47
  48 struct rpmsg_device;
  49 struct rpmsg_endpoint;
  50 struct rpmsg_device_ops;
  51 struct rpmsg_endpoint_ops;
  52
  53 /**
  54  * struct rpmsg_channel_info - channel info representation
  55  * @name: name of service
  56  * @src: local address
  57  * @dst: destination address
  58  */
  59 struct rpmsg_channel_info {
  60         char name[RPMSG_NAME_SIZE];
  61         u32 src;
  62         u32 dst;
  63 };
  64
  65 /**
  66  * rpmsg_device - device that belong to the rpmsg bus
  67  * @dev: the device struct
  68  * @id: device id (used to match between rpmsg drivers and devices)
  69  * @driver_override: driver name to force a match
  70  * @src: local address
  71  * @dst: destination address
  72  * @ept: the rpmsg endpoint of this channel
  73  * @announce: if set, rpmsg will announce the creation/removal of this channel
  74  */
  75 struct rpmsg_device {
  76         struct device dev;
  77         struct rpmsg_device_id id;
  78         char *driver_override;
  79         u32 src;
  80         u32 dst;
  81         struct rpmsg_endpoint *ept;
  82         bool announce;
  83
  84         const struct rpmsg_device_ops *ops;
  85 };
  86
  87 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
  88
  89 /**
  90  * struct rpmsg_endpoint - binds a local rpmsg address to its user
  91  * @rpdev: rpmsg channel device
  92  * @refcount: when this drops to zero, the ept is deallocated
  93  * @cb: rx callback handler
  94  * @cb_lock: must be taken before accessing/changing @cb
  95  * @addr: local rpmsg address
  96  * @priv: private data for the driver's use
  97  *
  98  * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
  99  * it binds an rpmsg address with an rx callback handler.
 100  *
 101  * Simple rpmsg drivers shouldn't use this struct directly, because
 102  * things just work: every rpmsg driver provides an rx callback upon
 103  * registering to the bus, and that callback is then bound to its rpmsg
 104  * address when the driver is probed. When relevant inbound messages arrive
 105  * (i.e. messages which their dst address equals to the src address of
 106  * the rpmsg channel), the driver's handler is invoked to process it.
 107  *
 108  * More complicated drivers though, that do need to allocate additional rpmsg
 109  * addresses, and bind them to different rx callbacks, must explicitly
 110  * create additional endpoints by themselves (see rpmsg_create_ept()).
 111  */
 112 struct rpmsg_endpoint {
 113         struct rpmsg_device *rpdev;
 114         struct kref refcount;
 115         rpmsg_rx_cb_t cb;
 116         struct mutex cb_lock;
 117         u32 addr;
 118         void *priv;
 119
 120         const struct rpmsg_endpoint_ops *ops;
 121 };
 122
 123 /**
 124  * struct rpmsg_driver - rpmsg driver struct
 125  * @drv: underlying device driver
 126  * @id_table: rpmsg ids serviced by this driver
 127  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
 128  * @remove: invoked when the rpmsg channel is removed
 129  * @callback: invoked when an inbound message is received on the channel
 130  */
 131 struct rpmsg_driver {
 132         struct device_driver drv;
 133         const struct rpmsg_device_id *id_table;
 134         int (*probe)(struct rpmsg_device *dev);
 135         void (*remove)(struct rpmsg_device *dev);
 136         int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 137 };
 138
 139 #if IS_ENABLED(CONFIG_RPMSG)
 140
 141 int register_rpmsg_device(struct rpmsg_device *dev);
 142 void unregister_rpmsg_device(struct rpmsg_device *dev);
 143 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
 144 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 145 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 146 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 147                                         rpmsg_rx_cb_t cb, void *priv,
 148                                         struct rpmsg_channel_info chinfo);
 149
 150 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
 151 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 152 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 153                           void *data, int len);
 154
 155 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
 156 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 157 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 158                              void *data, int len);
 159
 160 unsigned int rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 161                         poll_table *wait);
 162
 163 #else
 164
 165 static inline int register_rpmsg_device(struct rpmsg_device *dev)
 166 {
 167         return -ENXIO;
 168 }
 169
 170 static inline void unregister_rpmsg_device(struct rpmsg_device *dev)
 171 {
 172         /* This shouldn't be possible */
 173         WARN_ON(1);
 174 }
 175
 176 static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
 177                                           struct module *owner)
 178 {
 179         /* This shouldn't be possible */
 180         WARN_ON(1);
 181
 182         return -ENXIO;
 183 }
 184
 185 static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
 186 {
 187         /* This shouldn't be possible */
 188         WARN_ON(1);
 189 }
 190
 191 static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 192 {
 193         /* This shouldn't be possible */
 194         WARN_ON(1);
 195 }
 196
 197 static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
 198                                                       rpmsg_rx_cb_t cb,
 199                                                       void *priv,
 200                                                       struct rpmsg_channel_info chinfo)
 201 {
 202         /* This shouldn't be possible */
 203         WARN_ON(1);
 204
 205         return ERR_PTR(-ENXIO);
 206 }
 207
 208 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 209 {
 210         /* This shouldn't be possible */
 211         WARN_ON(1);
 212
 213         return -ENXIO;
 214 }
 215
 216 static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
 217                                u32 dst)
 218 {
 219         /* This shouldn't be possible */
 220         WARN_ON(1);
 221
 222         return -ENXIO;
 223
 224 }
 225
 226 static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
 227                                         u32 dst, void *data, int len)
 228 {
 229         /* This shouldn't be possible */
 230         WARN_ON(1);
 231
 232         return -ENXIO;
 233 }
 234
 235 static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 236 {
 237         /* This shouldn't be possible */
 238         WARN_ON(1);
 239
 240         return -ENXIO;
 241 }
 242
 243 static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
 244                                   int len, u32 dst)
 245 {
 246         /* This shouldn't be possible */
 247         WARN_ON(1);
 248
 249         return -ENXIO;
 250 }
 251
 252 static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
 253                                            u32 dst, void *data, int len)
 254 {
 255         /* This shouldn't be possible */
 256         WARN_ON(1);
 257
 258         return -ENXIO;
 259 }
 260
 261 static inline unsigned int rpmsg_poll(struct rpmsg_endpoint *ept,
 262                                       struct file *filp, poll_table *wait)
 263 {
 264         /* This shouldn't be possible */
 265         WARN_ON(1);
 266
 267         return 0;
 268 }
 269
 270 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 271
 272 /* use a macro to avoid include chaining to get THIS_MODULE */
 273 #define register_rpmsg_driver(drv) \
 274         __register_rpmsg_driver(drv, THIS_MODULE)
 275
 276 /**
 277  * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
 278  * @__rpmsg_driver: rpmsg_driver struct
 279  *
 280  * Helper macro for rpmsg drivers which do not do anything special in module
 281  * init/exit. This eliminates a lot of boilerplate.  Each module may only
 282  * use this macro once, and calling it replaces module_init() and module_exit()
 283  */
 284 #define module_rpmsg_driver(__rpmsg_driver) \
 285         module_driver(__rpmsg_driver, register_rpmsg_driver, \
 286                         unregister_rpmsg_driver)
 287
 288 #endif /* _LINUX_RPMSG_H */