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