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 * struct rpmsg_channel_info - channel info representation 102 * @name: name of service 103 * @src: local address 104 * @dst: destination address 105 */ 106 struct rpmsg_channel_info { 107 char name[RPMSG_NAME_SIZE]; 108 u32 src; 109 u32 dst; 110 }; 111 112 /** 113 * rpmsg_channel - devices that belong to the rpmsg bus are called channels 114 * @vrp: the remote processor this channel belongs to 115 * @dev: the device struct 116 * @id: device id (used to match between rpmsg drivers and devices) 117 * @src: local address 118 * @dst: destination address 119 * @ept: the rpmsg endpoint of this channel 120 * @announce: if set, rpmsg will announce the creation/removal of this channel 121 */ 122 struct rpmsg_channel { 123 struct virtproc_info *vrp; 124 struct device dev; 125 struct rpmsg_device_id id; 126 u32 src; 127 u32 dst; 128 struct rpmsg_endpoint *ept; 129 bool announce; 130 }; 131 132 typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32); 133 134 /** 135 * struct rpmsg_endpoint - binds a local rpmsg address to its user 136 * @rpdev: rpmsg channel device 137 * @refcount: when this drops to zero, the ept is deallocated 138 * @cb: rx callback handler 139 * @cb_lock: must be taken before accessing/changing @cb 140 * @addr: local rpmsg address 141 * @priv: private data for the driver's use 142 * 143 * In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as 144 * it binds an rpmsg address with an rx callback handler. 145 * 146 * Simple rpmsg drivers shouldn't use this struct directly, because 147 * things just work: every rpmsg driver provides an rx callback upon 148 * registering to the bus, and that callback is then bound to its rpmsg 149 * address when the driver is probed. When relevant inbound messages arrive 150 * (i.e. messages which their dst address equals to the src address of 151 * the rpmsg channel), the driver's handler is invoked to process it. 152 * 153 * More complicated drivers though, that do need to allocate additional rpmsg 154 * addresses, and bind them to different rx callbacks, must explicitly 155 * create additional endpoints by themselves (see rpmsg_create_ept()). 156 */ 157 struct rpmsg_endpoint { 158 struct rpmsg_channel *rpdev; 159 struct kref refcount; 160 rpmsg_rx_cb_t cb; 161 struct mutex cb_lock; 162 u32 addr; 163 void *priv; 164 }; 165 166 /** 167 * struct rpmsg_driver - rpmsg driver struct 168 * @drv: underlying device driver 169 * @id_table: rpmsg ids serviced by this driver 170 * @probe: invoked when a matching rpmsg channel (i.e. device) is found 171 * @remove: invoked when the rpmsg channel is removed 172 * @callback: invoked when an inbound message is received on the channel 173 */ 174 struct rpmsg_driver { 175 struct device_driver drv; 176 const struct rpmsg_device_id *id_table; 177 int (*probe)(struct rpmsg_channel *dev); 178 void (*remove)(struct rpmsg_channel *dev); 179 void (*callback)(struct rpmsg_channel *, void *, int, void *, u32); 180 }; 181 182 int __register_rpmsg_driver(struct rpmsg_driver *drv, struct module *owner); 183 void unregister_rpmsg_driver(struct rpmsg_driver *drv); 184 void rpmsg_destroy_ept(struct rpmsg_endpoint *); 185 struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *, 186 rpmsg_rx_cb_t cb, void *priv, 187 struct rpmsg_channel_info chinfo); 188 int 189 rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool); 190 191 /* use a macro to avoid include chaining to get THIS_MODULE */ 192 #define register_rpmsg_driver(drv) \ 193 __register_rpmsg_driver(drv, THIS_MODULE) 194 195 /** 196 * module_rpmsg_driver() - Helper macro for registering an rpmsg driver 197 * @__rpmsg_driver: rpmsg_driver struct 198 * 199 * Helper macro for rpmsg drivers which do not do anything special in module 200 * init/exit. This eliminates a lot of boilerplate. Each module may only 201 * use this macro once, and calling it replaces module_init() and module_exit() 202 */ 203 #define module_rpmsg_driver(__rpmsg_driver) \ 204 module_driver(__rpmsg_driver, register_rpmsg_driver, \ 205 unregister_rpmsg_driver) 206 207 /** 208 * rpmsg_send() - send a message across to the remote processor 209 * @ept: the rpmsg endpoint 210 * @data: payload of message 211 * @len: length of payload 212 * 213 * This function sends @data of length @len on the @ept endpoint. 214 * The message will be sent to the remote processor which the @ept 215 * endpoint belongs to, using @ept's address and its associated rpmsg 216 * device destination addresses. 217 * In case there are no TX buffers available, the function will block until 218 * one becomes available, or a timeout of 15 seconds elapses. When the latter 219 * happens, -ERESTARTSYS is returned. 220 * 221 * Can only be called from process context (for now). 222 * 223 * Returns 0 on success and an appropriate error value on failure. 224 */ 225 static inline int rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len) 226 { 227 struct rpmsg_channel *rpdev = ept->rpdev; 228 u32 src = ept->addr, dst = rpdev->dst; 229 230 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); 231 } 232 233 /** 234 * rpmsg_sendto() - send a message across to the remote processor, specify dst 235 * @ept: the rpmsg endpoint 236 * @data: payload of message 237 * @len: length of payload 238 * @dst: destination address 239 * 240 * This function sends @data of length @len to the remote @dst address. 241 * The message will be sent to the remote processor which the @ept 242 * endpoint belongs to, using @ept's address as source. 243 * In case there are no TX buffers available, the function will block until 244 * one becomes available, or a timeout of 15 seconds elapses. When the latter 245 * happens, -ERESTARTSYS is returned. 246 * 247 * Can only be called from process context (for now). 248 * 249 * Returns 0 on success and an appropriate error value on failure. 250 */ 251 static inline 252 int rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) 253 { 254 struct rpmsg_channel *rpdev = ept->rpdev; 255 u32 src = ept->addr; 256 257 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); 258 } 259 260 /** 261 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses 262 * @ept: the rpmsg endpoint 263 * @src: source address 264 * @dst: destination address 265 * @data: payload of message 266 * @len: length of payload 267 * 268 * This function sends @data of length @len to the remote @dst address, 269 * and uses @src as the source address. 270 * The message will be sent to the remote processor which the @ept 271 * endpoint belongs to. 272 * In case there are no TX buffers available, the function will block until 273 * one becomes available, or a timeout of 15 seconds elapses. When the latter 274 * happens, -ERESTARTSYS is returned. 275 * 276 * Can only be called from process context (for now). 277 * 278 * Returns 0 on success and an appropriate error value on failure. 279 */ 280 static inline 281 int rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, 282 void *data, int len) 283 { 284 struct rpmsg_channel *rpdev = ept->rpdev; 285 286 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true); 287 } 288 289 /** 290 * rpmsg_send() - send a message across to the remote processor 291 * @ept: the rpmsg endpoint 292 * @data: payload of message 293 * @len: length of payload 294 * 295 * This function sends @data of length @len on the @ept endpoint. 296 * The message will be sent to the remote processor which the @ept 297 * endpoint belongs to, using @ept's address as source and its associated 298 * rpdev's address as destination. 299 * In case there are no TX buffers available, the function will immediately 300 * return -ENOMEM without waiting until one becomes available. 301 * 302 * Can only be called from process context (for now). 303 * 304 * Returns 0 on success and an appropriate error value on failure. 305 */ 306 static inline 307 int rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len) 308 { 309 struct rpmsg_channel *rpdev = ept->rpdev; 310 u32 src = ept->addr, dst = rpdev->dst; 311 312 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); 313 } 314 315 /** 316 * rpmsg_sendto() - send a message across to the remote processor, specify dst 317 * @ept: the rpmsg endpoint 318 * @data: payload of message 319 * @len: length of payload 320 * @dst: destination address 321 * 322 * This function sends @data of length @len to the remote @dst address. 323 * The message will be sent to the remote processor which the @ept 324 * endpoint belongs to, using @ept's address as source. 325 * In case there are no TX buffers available, the function will immediately 326 * return -ENOMEM without waiting until one becomes available. 327 * 328 * Can only be called from process context (for now). 329 * 330 * Returns 0 on success and an appropriate error value on failure. 331 */ 332 static inline 333 int rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst) 334 { 335 struct rpmsg_channel *rpdev = ept->rpdev; 336 u32 src = ept->addr; 337 338 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); 339 } 340 341 /** 342 * rpmsg_send_offchannel() - send a message using explicit src/dst addresses 343 * @ept: the rpmsg endpoint 344 * @src: source address 345 * @dst: destination address 346 * @data: payload of message 347 * @len: length of payload 348 * 349 * This function sends @data of length @len to the remote @dst address, 350 * and uses @src as the source address. 351 * The message will be sent to the remote processor which the @ept 352 * endpoint belongs to. 353 * In case there are no TX buffers available, the function will immediately 354 * return -ENOMEM without waiting until one becomes available. 355 * 356 * Can only be called from process context (for now). 357 * 358 * Returns 0 on success and an appropriate error value on failure. 359 */ 360 static inline 361 int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst, 362 void *data, int len) 363 { 364 struct rpmsg_channel *rpdev = ept->rpdev; 365 366 return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false); 367 } 368 369 #endif /* _LINUX_RPMSG_H */ 370