include/linux/rpmsg.h

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2 /*
   3  * Remote processor messaging
   4  *
   5  * Copyright (C) 2011 Texas Instruments, Inc.
   6  * Copyright (C) 2011 Google, Inc.
   7  * All rights reserved.
   8  */
   9
  10 #ifndef _LINUX_RPMSG_H
  11 #define _LINUX_RPMSG_H
  12
  13 #include <linux/types.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/mod_devicetable.h>
  17 #include <linux/kref.h>
  18 #include <linux/mutex.h>
  19 #include <linux/poll.h>
  20
  21 #define RPMSG_ADDR_ANY          0xFFFFFFFF
  22
  23 struct rpmsg_device;
  24 struct rpmsg_endpoint;
  25 struct rpmsg_device_ops;
  26 struct rpmsg_endpoint_ops;
  27
  28 /**
  29  * struct rpmsg_channel_info - channel info representation
  30  * @name: name of service
  31  * @src: local address
  32  * @dst: destination address
  33  */
  34 struct rpmsg_channel_info {
  35         char name[RPMSG_NAME_SIZE];
  36         u32 src;
  37         u32 dst;
  38 };
  39
  40 /**
  41  * rpmsg_device - device that belong to the rpmsg bus
  42  * @dev: the device struct
  43  * @id: device id (used to match between rpmsg drivers and devices)
  44  * @driver_override: driver name to force a match
  45  * @src: local address
  46  * @dst: destination address
  47  * @ept: the rpmsg endpoint of this channel
  48  * @announce: if set, rpmsg will announce the creation/removal of this channel
  49  */
  50 struct rpmsg_device {
  51         struct device dev;
  52         struct rpmsg_device_id id;
  53         char *driver_override;
  54         u32 src;
  55         u32 dst;
  56         struct rpmsg_endpoint *ept;
  57         bool announce;
  58
  59         const struct rpmsg_device_ops *ops;
  60 };
  61
  62 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
  63
  64 /**
  65  * struct rpmsg_endpoint - binds a local rpmsg address to its user
  66  * @rpdev: rpmsg channel device
  67  * @refcount: when this drops to zero, the ept is deallocated
  68  * @cb: rx callback handler
  69  * @cb_lock: must be taken before accessing/changing @cb
  70  * @addr: local rpmsg address
  71  * @priv: private data for the driver's use
  72  *
  73  * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
  74  * it binds an rpmsg address with an rx callback handler.
  75  *
  76  * Simple rpmsg drivers shouldn't use this struct directly, because
  77  * things just work: every rpmsg driver provides an rx callback upon
  78  * registering to the bus, and that callback is then bound to its rpmsg
  79  * address when the driver is probed. When relevant inbound messages arrive
  80  * (i.e. messages which their dst address equals to the src address of
  81  * the rpmsg channel), the driver's handler is invoked to process it.
  82  *
  83  * More complicated drivers though, that do need to allocate additional rpmsg
  84  * addresses, and bind them to different rx callbacks, must explicitly
  85  * create additional endpoints by themselves (see rpmsg_create_ept()).
  86  */
  87 struct rpmsg_endpoint {
  88         struct rpmsg_device *rpdev;
  89         struct kref refcount;
  90         rpmsg_rx_cb_t cb;
  91         struct mutex cb_lock;
  92         u32 addr;
  93         void *priv;
  94
  95         const struct rpmsg_endpoint_ops *ops;
  96 };
  97
  98 /**
  99  * struct rpmsg_driver - rpmsg driver struct
 100  * @drv: underlying device driver
 101  * @id_table: rpmsg ids serviced by this driver
 102  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
 103  * @remove: invoked when the rpmsg channel is removed
 104  * @callback: invoked when an inbound message is received on the channel
 105  */
 106 struct rpmsg_driver {
 107         struct device_driver drv;
 108         const struct rpmsg_device_id *id_table;
 109         int (*probe)(struct rpmsg_device *dev);
 110         void (*remove)(struct rpmsg_device *dev);
 111         int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
 112 };
 113
 114 #if IS_ENABLED(CONFIG_RPMSG)
 115
 116 int register_rpmsg_device(struct rpmsg_device *dev);
 117 void unregister_rpmsg_device(struct rpmsg_device *dev);
 118 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner);
 119 void unregister_rpmsg_driver(struct rpmsg_driver *drv);
 120 void rpmsg_destroy_ept(struct rpmsg_endpoint *);
 121 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *,
 122                                         rpmsg_rx_cb_t cb, void *priv,
 123                                         struct rpmsg_channel_info chinfo);
 124
 125 int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
 126 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 127 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 128                           void *data, int len);
 129
 130 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
 131 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst);
 132 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 133                              void *data, int len);
 134
 135 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 136                         poll_table *wait);
 137
 138 #else
 139
 140 static inline int register_rpmsg_device(struct rpmsg_device *dev)
 141 {
 142         return -ENXIO;
 143 }
 144
 145 static inline void unregister_rpmsg_device(struct rpmsg_device *dev)
 146 {
 147         /* This shouldn't be possible */
 148         WARN_ON(1);
 149 }
 150
 151 static inline int __register_rpmsg_driver(struct rpmsg_driver *drv,
 152                                           struct module *owner)
 153 {
 154         /* This shouldn't be possible */
 155         WARN_ON(1);
 156
 157         return -ENXIO;
 158 }
 159
 160 static inline void unregister_rpmsg_driver(struct rpmsg_driver *drv)
 161 {
 162         /* This shouldn't be possible */
 163         WARN_ON(1);
 164 }
 165
 166 static inline void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 167 {
 168         /* This shouldn't be possible */
 169         WARN_ON(1);
 170 }
 171
 172 static inline struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_device *rpdev,
 173                                                       rpmsg_rx_cb_t cb,
 174                                                       void *priv,
 175                                                       struct rpmsg_channel_info chinfo)
 176 {
 177         /* This shouldn't be possible */
 178         WARN_ON(1);
 179
 180         return ERR_PTR(-ENXIO);
 181 }
 182
 183 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
 184 {
 185         /* This shouldn't be possible */
 186         WARN_ON(1);
 187
 188         return -ENXIO;
 189 }
 190
 191 static inline int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
 192                                u32 dst)
 193 {
 194         /* This shouldn't be possible */
 195         WARN_ON(1);
 196
 197         return -ENXIO;
 198
 199 }
 200
 201 static inline int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
 202                                         u32 dst, void *data, int len)
 203 {
 204         /* This shouldn't be possible */
 205         WARN_ON(1);
 206
 207         return -ENXIO;
 208 }
 209
 210 static inline int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 211 {
 212         /* This shouldn't be possible */
 213         WARN_ON(1);
 214
 215         return -ENXIO;
 216 }
 217
 218 static inline int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
 219                                   int len, u32 dst)
 220 {
 221         /* This shouldn't be possible */
 222         WARN_ON(1);
 223
 224         return -ENXIO;
 225 }
 226
 227 static inline int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
 228                                            u32 dst, void *data, int len)
 229 {
 230         /* This shouldn't be possible */
 231         WARN_ON(1);
 232
 233         return -ENXIO;
 234 }
 235
 236 static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
 237                                       struct file *filp, poll_table *wait)
 238 {
 239         /* This shouldn't be possible */
 240         WARN_ON(1);
 241
 242         return 0;
 243 }
 244
 245 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 246
 247 /* use a macro to avoid include chaining to get THIS_MODULE */
 248 #define register_rpmsg_driver(drv) \
 249         __register_rpmsg_driver(drv, THIS_MODULE)
 250
 251 /**
 252  * module_rpmsg_driver() - Helper macro for registering an rpmsg driver
 253  * @__rpmsg_driver: rpmsg_driver struct
 254  *
 255  * Helper macro for rpmsg drivers which do not do anything special in module
 256  * init/exit. This eliminates a lot of boilerplate.  Each module may only
 257  * use this macro once, and calling it replaces module_init() and module_exit()
 258  */
 259 #define module_rpmsg_driver(__rpmsg_driver) \
 260         module_driver(__rpmsg_driver, register_rpmsg_driver, \
 261                         unregister_rpmsg_driver)
 262
 263 #endif /* _LINUX_RPMSG_H */