1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef _CHRE_EVENT_H_ 18 #define _CHRE_EVENT_H_ 19 20 /** 21 * @file 22 * Context Hub Runtime Environment API dealing with events and messages. 23 */ 24 25 #include <stdbool.h> 26 #include <stdint.h> 27 #include <stdlib.h> 28 29 #ifdef __cplusplus 30 extern "C" { 31 #endif 32 33 /** 34 * The CHRE implementation is required to provide the following 35 * preprocessor defines via the build system. 36 * 37 * CHRE_MESSAGE_TO_HOST_MAX_SIZE: The maximum size, in bytes, allowed for 38 * a message sent to chreSendMessageToHost(). This must be at least 39 * CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE. 40 */ 41 42 #ifndef CHRE_MESSAGE_TO_HOST_MAX_SIZE 43 #error CHRE_MESSAGE_TO_HOST_MAX_SIZE must be defined by the Context Hub Runtime Environment implementation 44 #endif 45 46 /** 47 * The minimum size, in bytes, any CHRE implementation will 48 * use for CHRE_MESSAGE_TO_HOST_MAX_SIZE. 49 */ 50 #define CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE 128 51 52 #if CHRE_MESSAGE_TO_HOST_MAX_SIZE < CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE 53 #error CHRE_MESSAGE_TO_HOST_MAX_SIZE is too small. 54 #endif 55 56 /** 57 * The lowest numerical value legal for a user-defined event. 58 * 59 * The system reserves all event values from 0 to 0x7FFF, inclusive. 60 * User events may use any value in the range 0x8000 to 0xFFFF, inclusive. 61 * 62 * Note that the same event values might be used by different nanoapps 63 * for different meanings. This is not a concern, as these values only 64 * have meaning when paired with the originating nanoapp. 65 */ 66 #define CHRE_EVENT_FIRST_USER_VALUE UINT16_C(0x8000) 67 68 /** 69 * nanoappHandleEvent argument: struct chreMessageFromHostData 70 * 71 * The format of the 'message' part of this structure is left undefined, 72 * and it's up to the nanoapp and host to have an established protocol 73 * beforehand. 74 */ 75 #define CHRE_EVENT_MESSAGE_FROM_HOST UINT16_C(0x0001) 76 77 /** 78 * nanoappHandleEvent argument: 'cookie' given to chreTimerSet() method. 79 * 80 * Indicates that a timer has elapsed, in accordance with how chreTimerSet() was 81 * invoked. 82 */ 83 #define CHRE_EVENT_TIMER UINT16_C(0x0002) 84 85 /** 86 * nanoappHandleEvent argument: struct chreNanoappInfo 87 * 88 * Indicates that a nanoapp has successfully started (its nanoappStart() 89 * function has been called, and it returned true) and is able to receive events 90 * sent via chreSendEvent(). Note that this event is not sent for nanoapps that 91 * were started prior to the current nanoapp - use chreGetNanoappInfo() to 92 * determine if another nanoapp is already running. 93 * 94 * @see chreConfigureNanoappInfoEvents 95 * @since v1.1 96 */ 97 #define CHRE_EVENT_NANOAPP_STARTED UINT16_C(0x0003) 98 99 /** 100 * nanoappHandleEvent argument: struct chreNanoappInfo 101 * 102 * Indicates that a nanoapp has stopped executing and is no longer able to 103 * receive events sent via chreSendEvent(). Any events sent prior to receiving 104 * this event are not guaranteed to have been delivered. 105 * 106 * @see chreConfigureNanoappInfoEvents 107 * @since v1.1 108 */ 109 #define CHRE_EVENT_NANOAPP_STOPPED UINT16_C(0x0004) 110 111 /** 112 * First possible value for CHRE_EVENT_SENSOR events. 113 * 114 * This allows us to separately define our CHRE_EVENT_SENSOR_* events in 115 * chre/sensor.h, without fear of collision with other event values. 116 */ 117 #define CHRE_EVENT_SENSOR_FIRST_EVENT UINT16_C(0x0100) 118 119 /** 120 * Last possible value for CHRE_EVENT_SENSOR events. 121 * 122 * This allows us to separately define our CHRE_EVENT_SENSOR_* events in 123 * chre/sensor.h, without fear of collision with other event values. 124 */ 125 #define CHRE_EVENT_SENSOR_LAST_EVENT UINT16_C(0x02FF) 126 127 /** 128 * First event in the block reserved for GNSS. These events are defined in 129 * chre/gnss.h. 130 */ 131 #define CHRE_EVENT_GNSS_FIRST_EVENT UINT16_C(0x0300) 132 #define CHRE_EVENT_GNSS_LAST_EVENT UINT16_C(0x030F) 133 134 /** 135 * First event in the block reserved for WiFi. These events are defined in 136 * chre/wifi.h. 137 */ 138 #define CHRE_EVENT_WIFI_FIRST_EVENT UINT16_C(0x0310) 139 #define CHRE_EVENT_WIFI_LAST_EVENT UINT16_C(0x031F) 140 141 /** 142 * First event in the block reserved for WWAN. These events are defined in 143 * chre/wwan.h. 144 */ 145 #define CHRE_EVENT_WWAN_FIRST_EVENT UINT16_C(0x0320) 146 #define CHRE_EVENT_WWAN_LAST_EVENT UINT16_C(0x032F) 147 148 /** 149 * First in the extended range of values dedicated for internal CHRE 150 * implementation usage. 151 * 152 * This range is semantically the same as the internal event range defined 153 * below, but has been extended to allow for more implementation-specific events 154 * to be used. 155 * 156 * @since v1.1 157 */ 158 #define CHRE_EVENT_INTERNAL_EXTENDED_FIRST_EVENT UINT16_C(0x7000) 159 160 /** 161 * First in a range of values dedicated for internal CHRE implementation usage. 162 * 163 * If a CHRE wishes to use events internally, any values within this range 164 * are assured not to be taken by future CHRE API additions. 165 */ 166 #define CHRE_EVENT_INTERNAL_FIRST_EVENT UINT16_C(0x7E00) 167 168 /** 169 * Last in a range of values dedicated for internal CHRE implementation usage. 170 * 171 * If a CHRE wishes to use events internally, any values within this range 172 * are assured not to be taken by future CHRE API additions. 173 */ 174 #define CHRE_EVENT_INTERNAL_LAST_EVENT UINT16_C(0x7FFF) 175 176 /** 177 * A special value for the hostEndpoint argument in 178 * chreSendMessageToHostEndpoint() that indicates that the message should be 179 * delivered to all host endpoints. This value will not be used in the 180 * hostEndpoint field of struct chreMessageFromHostData supplied with 181 * CHRE_EVENT_MESSAGE_FROM_HOST. 182 * 183 * @since v1.1 184 */ 185 #define CHRE_HOST_ENDPOINT_BROADCAST UINT16_C(0xFFFF) 186 187 /** 188 * A special value for hostEndpoint in struct chreMessageFromHostData that 189 * indicates that a host endpoint is unknown or otherwise unspecified. This 190 * value may be received in CHRE_EVENT_MESSAGE_FROM_HOST, but it is not valid to 191 * provide it to chreSendMessageToHostEndpoint(). 192 * 193 * @since v1.1 194 */ 195 #define CHRE_HOST_ENDPOINT_UNSPECIFIED UINT16_C(0xFFFE) 196 197 198 /** 199 * Data provided with CHRE_EVENT_MESSAGE_FROM_HOST. 200 */ 201 struct chreMessageFromHostData { 202 /** 203 * Message type supplied by the host. 204 * 205 * @note In CHRE API v1.0, support for forwarding this field from the host 206 * was not strictly required, and some implementations did not support it. 207 * However, its support is mandatory as of v1.1. 208 */ 209 union { 210 /** 211 * The preferred name to use when referencing this field. 212 * 213 * @since v1.1 214 */ 215 uint32_t messageType; 216 217 /** 218 * @deprecated This is the name for the messageType field used in v1.0. 219 * Left to allow code to compile against both v1.0 and v1.1 of the API 220 * definition without needing to use #ifdefs. This will be removed in a 221 * future API update - use messageType instead. 222 */ 223 uint32_t reservedMessageType; 224 }; 225 226 /** 227 * The size, in bytes of the following 'message'. 228 * 229 * This can be 0. 230 */ 231 uint32_t messageSize; 232 233 /** 234 * The message from the host. 235 * 236 * These contents are of a format that the host and nanoapp must have 237 * established beforehand. 238 * 239 * This data is 'messageSize' bytes in length. Note that if 'messageSize' 240 * is 0, this might be NULL. 241 */ 242 const void *message; 243 244 /** 245 * An identifier for the host-side entity that sent this message. Unless 246 * this is set to CHRE_HOST_ENDPOINT_UNSPECIFIED, it can be used in 247 * chreSendMessageToHostEndpoint() to send a directed reply that will only 248 * be received by the given entity on the host. Endpoint identifiers are 249 * opaque values assigned at runtime, so they cannot be assumed to always 250 * describe a specific entity across restarts. 251 * 252 * If running on a CHRE API v1.0 implementation, this field will always be 253 * set to CHRE_HOST_ENDPOINT_UNSPECIFIED. 254 * 255 * @since v1.1 256 */ 257 uint16_t hostEndpoint; 258 }; 259 260 /** 261 * Provides metadata for a nanoapp in the system. 262 */ 263 struct chreNanoappInfo { 264 /** 265 * Nanoapp identifier. The convention for populating this value is to set 266 * the most significant 5 bytes to a value that uniquely identifies the 267 * vendor, and the lower 3 bytes identify the nanoapp. 268 */ 269 uint64_t appId; 270 271 /** 272 * Nanoapp version. The semantics of this field are defined by the nanoapp, 273 * however nanoapps are recommended to follow the same scheme used for the 274 * CHRE version exposed in chreGetVersion(). That is, the most significant 275 * byte represents the major version, the next byte the minor version, and 276 * the lower two bytes the patch version. 277 */ 278 uint32_t version; 279 280 /** 281 * The instance ID of this nanoapp, which can be used in chreSendEvent() to 282 * address an event specifically to this nanoapp. This identifier is 283 * guaranteed to be unique among all nanoapps in the system. 284 */ 285 uint32_t instanceId; 286 }; 287 288 /** 289 * Callback which frees data associated with an event. 290 * 291 * This callback is (optionally) provided to the chreSendEvent() method as 292 * a means for freeing the event data and performing any other cleanup 293 * necessary when the event is completed. When this callback is invoked, 294 * 'eventData' is no longer needed and can be released. 295 * 296 * @param eventType The 'eventType' argument from chreSendEvent(). 297 * @param eventData The 'eventData' argument from chreSendEvent(). 298 * 299 * @see chreSendEvent 300 */ 301 typedef void (chreEventCompleteFunction)(uint16_t eventType, void *eventData); 302 303 /** 304 * Callback which frees a message. 305 * 306 * This callback is (optionally) provided to the chreSendMessageToHost() method 307 * as a means for freeing the message. When this callback is invoked, 308 * 'message' is no longer needed and can be released. Note that this in 309 * no way assures that said message did or did not make it to the host, simply 310 * that this memory is no longer needed. 311 * 312 * @param message The 'message' argument from chreSendMessageToHost(). 313 * @param messageSize The 'messageSize' argument from chreSendMessageToHost(). 314 * 315 * @see chreSendMessageToHost 316 */ 317 typedef void (chreMessageFreeFunction)(void *message, size_t messageSize); 318 319 320 /** 321 * Enqueue an event to be sent to another nanoapp. 322 * 323 * Note: This version of the API does not give an easy means to discover 324 * another nanoapp's instance ID. For now, events will need to be sent to/from 325 * the host to initially discover these IDs. 326 * 327 * @param eventType This is a user-defined event type, of at least the 328 * value CHRE_EVENT_FIRST_USER_VALUE. It is illegal to attempt to use any 329 * of the CHRE_EVENT_* values reserved for the CHRE. 330 * @param eventData A pointer value that will be understood by the receiving 331 * app. Note that NULL is perfectly acceptable. It also is not required 332 * that this be a valid pointer, although if this nanoapp is intended to 333 * work on arbitrary CHRE implementations, then the size of a 334 * pointer cannot be assumed to be a certain size. Note that the caller 335 * no longer owns this memory after the call. 336 * @param freeCallback A pointer to a callback function. After the lifetime 337 * of 'eventData' is over (either through successful delivery or the event 338 * being dropped), this callback will be invoked. This argument is allowed 339 * to be NULL, in which case no callback will be invoked. 340 * @param targetInstanceId The ID of the instance we're delivering this event 341 * to. Note that this is allowed to be our own instance. 342 * @returns true if the event was enqueued, false otherwise. Note that even 343 * if this method returns 'false', the 'freeCallback' will be invoked, 344 * if non-NULL. Note in the 'false' case, the 'freeCallback' may be 345 * invoked directly from within chreSendEvent(), so it's necessary 346 * for nanoapp authors to avoid possible recursion with this. 347 * 348 * @see chreEventDataFreeFunction 349 */ 350 bool chreSendEvent(uint16_t eventType, void *eventData, 351 chreEventCompleteFunction *freeCallback, 352 uint32_t targetInstanceId); 353 354 /** 355 * Send a message to the host, using the broadcast endpoint 356 * CHRE_HOST_ENDPOINT_BROADCAST. Refer to chreSendMessageToHostEndpoint() for 357 * further details. 358 * 359 * @see chreSendMessageToHostEndpoint 360 * 361 * @deprecated New code should use chreSendMessageToHostEndpoint() instead of 362 * this function. A future update to the API may cause references to this 363 * function to produce a compiler warning. 364 */ 365 bool chreSendMessageToHost(void *message, uint32_t messageSize, 366 uint32_t messageType, 367 chreMessageFreeFunction *freeCallback); 368 369 /** 370 * Send a message to the host. 371 * 372 * This message is by definition arbitrarily defined. Since we're not 373 * just a passing a pointer to memory around the system, but need to copy 374 * this into various buffers to send it to the host, the CHRE 375 * implementation cannot be asked to support an arbitrarily large message 376 * size. As a result, we have the CHRE implementation define 377 * CHRE_MESSAGE_TO_HOST_MAX_SIZE. 378 * 379 * CHRE_MESSAGE_TO_HOST_MAX_SIZE is not given a value by the Platform API. The 380 * Platform API does define CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, and requires 381 * that CHRE_MESSAGE_TO_HOST_MAX_SIZE is at least that value. 382 * 383 * As a result, if your message sizes are all less than 384 * CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, then you have no concerns on any 385 * CHRE implementation. If your message sizes are larger, you'll need to 386 * come up with a strategy for splitting your message across several calls 387 * to this method. As long as that strategy works for 388 * CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, it will work across all CHRE 389 * implementations (although on some implementations less calls to this 390 * method may be necessary). 391 * 392 * @param message Pointer to a block of memory to send to the host. 393 * NULL is acceptable only if messageSize is 0. If non-NULL, this 394 * must be a legitimate pointer (that is, unlike chreSendEvent(), a small 395 * integral value cannot be cast to a pointer for this). Note that the 396 * caller no longer owns this memory after the call. 397 * @param messageSize The size, in bytes, of the given message. 398 * This cannot exceed CHRE_MESSAGE_TO_HOST_MAX_SIZE. 399 * @param messageType Message type sent to the app on the host. 400 * NOTE: In CHRE API v1.0, support for forwarding this field to the host was 401 * not strictly required, and some implementations did not support it. 402 * However, its support is mandatory as of v1.1. 403 * @param hostEndpoint An identifier for the intended recipient of the message, 404 * or CHRE_HOST_ENDPOINT_BROADCAST if all registered endpoints on the host 405 * should receive the message. Endpoint identifiers are assigned on the 406 * host side, and nanoapps may learn of the host endpoint ID of an intended 407 * recipient via an initial message sent by the host. This parameter is 408 * always treated as CHRE_HOST_ENDPOINT_BROADCAST if running on a CHRE API 409 * v1.0 implementation. 410 * @param freeCallback A pointer to a callback function. After the lifetime 411 * of 'message' is over (which does not assure that 'message' made it to 412 * the host, just that the transport layer no longer needs this memory), 413 * this callback will be invoked. This argument is allowed 414 * to be NULL, in which case no callback will be invoked. 415 * @returns true if the message was accepted for transmission, false otherwise. 416 * Note that even if this method returns 'false', the 'freeCallback' will 417 * be invoked, if non-NULL. In either case, the 'freeCallback' may be 418 * invoked directly from within chreSendMessageToHost(), so it's necessary 419 * for nanoapp authors to avoid possible recursion with this. 420 * 421 * @see chreMessageFreeFunction 422 * 423 * @since v1.1 424 */ 425 bool chreSendMessageToHostEndpoint(void *message, size_t messageSize, 426 uint32_t messageType, uint16_t hostEndpoint, 427 chreMessageFreeFunction *freeCallback); 428 429 /** 430 * Queries for information about a nanoapp running in the system. 431 * 432 * In the current API, appId is required to be unique, i.e. there cannot be two 433 * nanoapps running concurrently with the same appId. If this restriction is 434 * removed in a future API version and multiple instances of the same appId are 435 * present, this function must always return the first app to start. 436 * 437 * @param appId Identifier for the nanoapp that the caller is requesting 438 * information about. 439 * @param info Output parameter. If this function returns true, this structure 440 * will be populated with details of the specified nanoapp. 441 * @returns true if a nanoapp with the given ID is currently running, and the 442 * supplied info parameter was populated with its information. 443 * 444 * @since v1.1 445 */ 446 bool chreGetNanoappInfoByAppId(uint64_t appId, struct chreNanoappInfo *info); 447 448 /** 449 * Queries for information about a nanoapp running in the system, using the 450 * runtime unique identifier. This method can be used to get information about 451 * the sender of an event. 452 * 453 * @param instanceId 454 * @param info Output parameter. If this function returns true, this structure 455 * will be populated with details of the specified nanoapp. 456 * @returns true if a nanoapp with the given instance ID is currently running, 457 * and the supplied info parameter was populated with its information. 458 * 459 * @since v1.1 460 */ 461 bool chreGetNanoappInfoByInstanceId(uint32_t instanceId, 462 struct chreNanoappInfo *info); 463 464 /** 465 * Configures whether this nanoapp will be notified when other nanoapps in the 466 * system start and stop, via CHRE_EVENT_NANOAPP_STARTED and 467 * CHRE_EVENT_NANOAPP_STOPPED. These events are disabled by default, and if a 468 * nanoapp is not interested in interacting with other nanoapps, then it does 469 * not need to register for them. However, if inter-nanoapp communication is 470 * desired, nanoapps are recommended to call this function from nanoappStart(). 471 * 472 * If running on a CHRE platform that only supports v1.0 of the CHRE API, this 473 * function has no effect. 474 * 475 * @param enable true to enable these events, false to disable 476 * 477 * @see CHRE_EVENT_NANOAPP_STARTED 478 * @see CHRE_EVENT_NANOAPP_STOPPED 479 * 480 * @since v1.1 481 */ 482 void chreConfigureNanoappInfoEvents(bool enable); 483 484 #ifdef __cplusplus 485 } 486 #endif 487 488 #endif /* _CHRE_EVENT_H_ */ 489 490
