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