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 * @since v1.1 95 */ 96 #define CHRE_EVENT_NANOAPP_STARTED UINT16_C(0x0003) 97 98 /** 99 * nanoappHandleEvent argument: struct chreNanoappInfo 100 * 101 * Indicates that a nanoapp has stopped executing and is no longer able to 102 * receive events sent via chreSendEvent(). Any events sent prior to receiving 103 * this event are not guaranteed to have been delivered. 104 * 105 * @since v1.1 106 */ 107 #define CHRE_EVENT_NANOAPP_STOPPED UINT16_C(0x0004) 108 109 /** 110 * First possible value for CHRE_EVENT_SENSOR events. 111 * 112 * This allows us to separately define our CHRE_EVENT_SENSOR_* events in 113 * chre/sensor.h, without fear of collision with other event values. 114 */ 115 #define CHRE_EVENT_SENSOR_FIRST_EVENT UINT16_C(0x0100) 116 117 /** 118 * Last possible value for CHRE_EVENT_SENSOR events. 119 * 120 * This allows us to separately define our CHRE_EVENT_SENSOR_* events in 121 * chre/sensor.h, without fear of collision with other event values. 122 */ 123 #define CHRE_EVENT_SENSOR_LAST_EVENT UINT16_C(0x02FF) 124 125 /** 126 * First event in the block reserved for GNSS. These events are defined in 127 * chre/gnss.h. 128 */ 129 #define CHRE_EVENT_GNSS_FIRST_EVENT UINT16_C(0x0300) 130 #define CHRE_EVENT_GNSS_LAST_EVENT UINT16_C(0x030F) 131 132 /** 133 * First event in the block reserved for WiFi. These events are defined in 134 * chre/wifi.h. 135 */ 136 #define CHRE_EVENT_WIFI_FIRST_EVENT UINT16_C(0x0310) 137 #define CHRE_EVENT_WIFI_LAST_EVENT UINT16_C(0x031F) 138 139 /** 140 * First event in the block reserved for WWAN. These events are defined in 141 * chre/wwan.h. 142 */ 143 #define CHRE_EVENT_WWAN_FIRST_EVENT UINT16_C(0x0320) 144 #define CHRE_EVENT_WWAN_LAST_EVENT UINT16_C(0x032F) 145 146 /** 147 * First in a range of values dedicated for internal CHRE implementation usage. 148 * 149 * If a CHRE wishes to use events internally, any values within this range 150 * are assured not to be taken by future CHRE API additions. 151 */ 152 #define CHRE_EVENT_INTERNAL_FIRST_EVENT UINT16_C(0x7E00) 153 154 /** 155 * Last in a range of values dedicated for internal CHRE implementation usage. 156 * 157 * If a CHRE wishes to use events internally, any values within this range 158 * are assured not to be taken by future CHRE API additions. 159 */ 160 #define CHRE_EVENT_INTERNAL_LAST_EVENT UINT16_C(0x7FFF) 161 162 /** 163 * A special value for the hostEndpoint argument in 164 * chreSendMessageToHostEndpoint() that indicates that the message should be 165 * delivered to all host endpoints. This value will not be used in the 166 * hostEndpoint field of struct chreMessageFromHostData supplied with 167 * CHRE_EVENT_MESSAGE_FROM_HOST. 168 * 169 * @since v1.1 170 */ 171 #define CHRE_HOST_ENDPOINT_BROADCAST UINT16_C(0xFFFF) 172 173 /** 174 * A special value for hostEndpoint in struct chreMessageFromHostData that 175 * indicates that a host endpoint is unknown or otherwise unspecified. This 176 * value may be received in CHRE_EVENT_MESSAGE_FROM_HOST, but it is not valid to 177 * provide it to chreSendMessageToHostEndpoint(). 178 * 179 * @since v1.1 180 */ 181 #define CHRE_HOST_ENDPOINT_UNSPECIFIED UINT16_C(0xFFFE) 182 183 184 /** 185 * Data provided with CHRE_EVENT_MESSAGE_FROM_HOST. 186 */ 187 struct chreMessageFromHostData { 188 /** 189 * Message type supplied by the host. 190 * 191 * NOTE: In CHRE API v1.0, support for forwarding this field from the host 192 * was not strictly required, and some implementations did not support it. 193 * However, its support is mandatory as of v1.1. 194 */ 195 uint32_t messageType; 196 197 /** 198 * The size, in bytes of the following 'message'. 199 * 200 * This can be 0. 201 */ 202 uint32_t messageSize; 203 204 /** 205 * The message from the host. 206 * 207 * These contents are of a format that the host and nanoapp must have 208 * established beforehand. 209 * 210 * This data is 'messageSize' bytes in length. Note that if 'messageSize' 211 * is 0, this might be NULL. 212 */ 213 const void *message; 214 215 /** 216 * An identifier for the host-side entity that sent this message. Unless 217 * this is set to CHRE_HOST_ENDPOINT_UNSPECIFIED, it can be used in 218 * chreSendMessageToHostEndpoint() to send a directed reply that will only 219 * be received by the given entity on the host. Endpoint identifiers are 220 * opaque values assigned at runtime, so they cannot be assumed to always 221 * describe a specific entity across restarts. 222 * 223 * If running on a CHRE API v1.0 implementation, this field will always be 224 * set to CHRE_HOST_ENDPOINT_UNSPECIFIED. 225 * 226 * @since v1.1 227 */ 228 uint16_t hostEndpoint; 229 }; 230 231 /** 232 * Provides metadata for a nanoapp in the system. 233 */ 234 struct chreNanoappInfo { 235 /** 236 * Nanoapp identifier. The convention for populating this value is to set 237 * the most significant 5 bytes to a value that uniquely identifies the 238 * vendor, and the lower 3 bytes identify the nanoapp. 239 */ 240 uint64_t appId; 241 242 /** 243 * Nanoapp version. The semantics of this field are defined by the nanoapp, 244 * however nanoapps are recommended to follow the same scheme used for the 245 * CHRE version exposed in chreGetVersion(). That is, the most significant 246 * byte represents the major version, the next byte the minor version, and 247 * the lower two bytes the patch version. 248 */ 249 uint32_t version; 250 251 /** 252 * The instance ID of this nanoapp, which can be used in chreSendEvent() to 253 * address an event specifically to this nanoapp. This identifier is 254 * guaranteed to be unique among all nanoapps in the system. 255 */ 256 uint32_t instanceId; 257 }; 258 259 /** 260 * Callback which frees data associated with an event. 261 * 262 * This callback is (optionally) provided to the chreSendEvent() method as 263 * a means for freeing the event data and performing any other cleanup 264 * necessary when the event is completed. When this callback is invoked, 265 * 'eventData' is no longer needed and can be released. 266 * 267 * @param eventType The 'eventType' argument from chreSendEvent(). 268 * @param eventData The 'eventData' argument from chreSendEvent(). 269 * 270 * @see chreSendEvent 271 */ 272 typedef void (chreEventCompleteFunction)(uint16_t eventType, void *eventData); 273 274 /** 275 * Callback which frees a message. 276 * 277 * This callback is (optionally) provided to the chreSendMessageToHost() method 278 * as a means for freeing the message. When this callback is invoked, 279 * 'message' is no longer needed and can be released. Note that this in 280 * no way assures that said message did or did not make it to the host, simply 281 * that this memory is no longer needed. 282 * 283 * @param message The 'message' argument from chreSendMessageToHost(). 284 * @param messageSize The 'messageSize' argument from chreSendMessageToHost(). 285 * 286 * @see chreSendMessageToHost 287 */ 288 typedef void (chreMessageFreeFunction)(void *message, size_t messageSize); 289 290 291 /** 292 * Enqueue an event to be sent to another nanoapp. 293 * 294 * Note: This version of the API does not give an easy means to discover 295 * another nanoapp's instance ID. For now, events will need to be sent to/from 296 * the host to initially discover these IDs. 297 * 298 * @param eventType This is a user-defined event type, of at least the 299 * value CHRE_EVENT_FIRST_USER_VALUE. It is illegal to attempt to use any 300 * of the CHRE_EVENT_* values reserved for the CHRE. 301 * @param eventData A pointer value that will be understood by the receiving 302 * app. Note that NULL is perfectly acceptable. It also is not required 303 * that this be a valid pointer, although if this nanoapp is intended to 304 * work on arbitrary CHRE implementations, then the size of a 305 * pointer cannot be assumed to be a certain size. Note that the caller 306 * no longer owns this memory after the call. 307 * @param freeCallback A pointer to a callback function. After the lifetime 308 * of 'eventData' is over (either through successful delivery or the event 309 * being dropped), this callback will be invoked. This argument is allowed 310 * to be NULL, in which case no callback will be invoked. 311 * @param targetInstanceId The ID of the instance we're delivering this event 312 * to. Note that this is allowed to be our own instance. 313 * @returns true if the event was enqueued, false otherwise. Note that even 314 * if this method returns 'false', the 'freeCallback' will be invoked, 315 * if non-NULL. Note in the 'false' case, the 'freeCallback' may be 316 * invoked directly from within chreSendEvent(), so it's necessary 317 * for nanoapp authors to avoid possible recursion with this. 318 * 319 * @see chreEventDataFreeFunction 320 */ 321 bool chreSendEvent(uint16_t eventType, void *eventData, 322 chreEventCompleteFunction *freeCallback, 323 uint32_t targetInstanceId); 324 325 /** 326 * Send a message to the host, using the broadcast endpoint 327 * CHRE_HOST_ENDPOINT_BROADCAST. Refer to chreSendMessageToHostEndpoint() for 328 * further details. 329 * 330 * @see chreSendMessageToHostEndpoint 331 * 332 * @deprecated New code should use chreSendMessageToHostEndpoint() instead of 333 * this function. A future update to the API may cause references to this 334 * function to produce a compiler warning. 335 */ 336 bool chreSendMessageToHost(void *message, uint32_t messageSize, 337 uint32_t messageType, 338 chreMessageFreeFunction *freeCallback); 339 340 /** 341 * Send a message to the host. 342 * 343 * This message is by definition arbitrarily defined. Since we're not 344 * just a passing a pointer to memory around the system, but need to copy 345 * this into various buffers to send it to the host, the CHRE 346 * implementation cannot be asked to support an arbitrarily large message 347 * size. As a result, we have the CHRE implementation define 348 * CHRE_MESSAGE_TO_HOST_MAX_SIZE. 349 * 350 * CHRE_MESSAGE_TO_HOST_MAX_SIZE is not given a value by the Platform API. The 351 * Platform API does define CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, and requires 352 * that CHRE_MESSAGE_TO_HOST_MAX_SIZE is at least that value. 353 * 354 * As a result, if your message sizes are all less than 355 * CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, then you have no concerns on any 356 * CHRE implementation. If your message sizes are larger, you'll need to 357 * come up with a strategy for splitting your message across several calls 358 * to this method. As long as that strategy works for 359 * CHRE_MESSAGE_TO_HOST_MINIMUM_MAX_SIZE, it will work across all CHRE 360 * implementations (although on some implementations less calls to this 361 * method may be necessary). 362 * 363 * @param message Pointer to a block of memory to send to the host. 364 * NULL is acceptable only if messageSize is 0. If non-NULL, this 365 * must be a legitimate pointer (that is, unlike chreSendEvent(), a small 366 * integral value cannot be cast to a pointer for this). Note that the 367 * caller no longer owns this memory after the call. 368 * @param messageSize The size, in bytes, of the given message. 369 * This cannot exceed CHRE_MESSAGE_TO_HOST_MAX_SIZE. 370 * @param messageType Message type sent to the app on the host. 371 * NOTE: In CHRE API v1.0, support for forwarding this field to the host was 372 * not strictly required, and some implementations did not support it. 373 * However, its support is mandatory as of v1.1. 374 * @param hostEndpoint An identifier for the intended recipient of the message, 375 * or CHRE_HOST_ENDPOINT_BROADCAST if all registered endpoints on the host 376 * should receive the message. Endpoint identifiers are assigned on the 377 * host side, and nanoapps may learn of the host endpoint ID of an intended 378 * recipient via an initial message sent by the host. This parameter is 379 * always treated as CHRE_HOST_ENDPOINT_BROADCAST if running on a CHRE API 380 * v1.0 implementation. 381 * @param freeCallback A pointer to a callback function. After the lifetime 382 * of 'message' is over (which does not assure that 'message' made it to 383 * the host, just that the transport layer no longer needs this memory), 384 * this callback will be invoked. This argument is allowed 385 * to be NULL, in which case no callback will be invoked. 386 * @returns true if the message was accepted for transmission, false otherwise. 387 * Note that even if this method returns 'false', the 'freeCallback' will 388 * be invoked, if non-NULL. In either case, the 'freeCallback' may be 389 * invoked directly from within chreSendMessageToHost(), so it's necessary 390 * for nanoapp authors to avoid possible recursion with this. 391 * 392 * @see chreMessageFreeFunction 393 * 394 * @since v1.1 395 */ 396 bool chreSendMessageToHostEndpoint(void *message, size_t messageSize, 397 uint32_t messageType, uint16_t hostEndpoint, 398 chreMessageFreeFunction *freeCallback); 399 400 /** 401 * Queries for information about a nanoapp running in the system. 402 * 403 * In the current API, appId is required to be unique, i.e. there cannot be two 404 * nanoapps running concurrently with the same appId. If this restriction is 405 * removed in a future API version and multiple instances of the same appId are 406 * present, this function must always return the first app to start. 407 * 408 * @param appId Identifier for the nanoapp that the caller is requesting 409 * information about. 410 * @param info Output parameter. If this function returns true, this structure 411 * will be populated with details of the specified nanoapp. 412 * @returns true if a nanoapp with the given ID is currently running, and the 413 * supplied info parameter was populated with its information. 414 * 415 * @since v1.1 416 */ 417 bool chreGetNanoappInfoByAppId(uint64_t appId, struct chreNanoappInfo *info); 418 419 /** 420 * Queries for information about a nanoapp running in the system, using the 421 * runtime unique identifier. This method can be used to get information about 422 * the sender of an event. 423 * 424 * @param instanceId 425 * @param info Output parameter. If this function returns true, this structure 426 * will be populated with details of the specified nanoapp. 427 * @returns true if a nanoapp with the given instance ID is currently running, 428 * and the supplied info parameter was populated with its information. 429 * 430 * @since v1.1 431 */ 432 bool chreGetNanoappInfoByInstanceId(uint32_t instanceId, 433 struct chreNanoappInfo *info); 434 435 436 #ifdef __cplusplus 437 } 438 #endif 439 440 #endif /* _CHRE_EVENT_H_ */ 441 442
