1 // SPDX-License-Identifier: GPL-2.0 2 // ChromeOS EC communication protocol helper functions 3 // 4 // Copyright (C) 2015 Google, Inc 5 6 #include <linux/mfd/cros_ec.h> 7 #include <linux/delay.h> 8 #include <linux/device.h> 9 #include <linux/module.h> 10 #include <linux/slab.h> 11 #include <asm/unaligned.h> 12 13 #define EC_COMMAND_RETRIES 50 14 15 static int prepare_packet(struct cros_ec_device *ec_dev, 16 struct cros_ec_command *msg) 17 { 18 struct ec_host_request *request; 19 u8 *out; 20 int i; 21 u8 csum = 0; 22 23 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION); 24 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size); 25 26 out = ec_dev->dout; 27 request = (struct ec_host_request *)out; 28 request->struct_version = EC_HOST_REQUEST_VERSION; 29 request->checksum = 0; 30 request->command = msg->command; 31 request->command_version = msg->version; 32 request->reserved = 0; 33 request->data_len = msg->outsize; 34 35 for (i = 0; i < sizeof(*request); i++) 36 csum += out[i]; 37 38 /* Copy data and update checksum */ 39 memcpy(out + sizeof(*request), msg->data, msg->outsize); 40 for (i = 0; i < msg->outsize; i++) 41 csum += msg->data[i]; 42 43 request->checksum = -csum; 44 45 return sizeof(*request) + msg->outsize; 46 } 47 48 static int send_command(struct cros_ec_device *ec_dev, 49 struct cros_ec_command *msg) 50 { 51 int ret; 52 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg); 53 54 if (ec_dev->proto_version > 2) 55 xfer_fxn = ec_dev->pkt_xfer; 56 else 57 xfer_fxn = ec_dev->cmd_xfer; 58 59 ret = (*xfer_fxn)(ec_dev, msg); 60 if (msg->result == EC_RES_IN_PROGRESS) { 61 int i; 62 struct cros_ec_command *status_msg; 63 struct ec_response_get_comms_status *status; 64 65 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status), 66 GFP_KERNEL); 67 if (!status_msg) 68 return -ENOMEM; 69 70 status_msg->version = 0; 71 status_msg->command = EC_CMD_GET_COMMS_STATUS; 72 status_msg->insize = sizeof(*status); 73 status_msg->outsize = 0; 74 75 /* 76 * Query the EC's status until it's no longer busy or 77 * we encounter an error. 78 */ 79 for (i = 0; i < EC_COMMAND_RETRIES; i++) { 80 usleep_range(10000, 11000); 81 82 ret = (*xfer_fxn)(ec_dev, status_msg); 83 if (ret == -EAGAIN) 84 continue; 85 if (ret < 0) 86 break; 87 88 msg->result = status_msg->result; 89 if (status_msg->result != EC_RES_SUCCESS) 90 break; 91 92 status = (struct ec_response_get_comms_status *) 93 status_msg->data; 94 if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) 95 break; 96 } 97 98 kfree(status_msg); 99 } 100 101 return ret; 102 } 103 104 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, 105 struct cros_ec_command *msg) 106 { 107 u8 *out; 108 u8 csum; 109 int i; 110 111 if (ec_dev->proto_version > 2) 112 return prepare_packet(ec_dev, msg); 113 114 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE); 115 out = ec_dev->dout; 116 out[0] = EC_CMD_VERSION0 + msg->version; 117 out[1] = msg->command; 118 out[2] = msg->outsize; 119 csum = out[0] + out[1] + out[2]; 120 for (i = 0; i < msg->outsize; i++) 121 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i]; 122 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum; 123 124 return EC_MSG_TX_PROTO_BYTES + msg->outsize; 125 } 126 EXPORT_SYMBOL(cros_ec_prepare_tx); 127 128 int cros_ec_check_result(struct cros_ec_device *ec_dev, 129 struct cros_ec_command *msg) 130 { 131 switch (msg->result) { 132 case EC_RES_SUCCESS: 133 return 0; 134 case EC_RES_IN_PROGRESS: 135 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n", 136 msg->command); 137 return -EAGAIN; 138 default: 139 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n", 140 msg->command, msg->result); 141 return 0; 142 } 143 } 144 EXPORT_SYMBOL(cros_ec_check_result); 145 146 /* 147 * cros_ec_get_host_event_wake_mask 148 * 149 * Get the mask of host events that cause wake from suspend. 150 * 151 * @ec_dev: EC device to call 152 * @msg: message structure to use 153 * @mask: result when function returns >=0. 154 * 155 * LOCKING: 156 * the caller has ec_dev->lock mutex, or the caller knows there is 157 * no other command in progress. 158 */ 159 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev, 160 struct cros_ec_command *msg, 161 uint32_t *mask) 162 { 163 struct ec_response_host_event_mask *r; 164 int ret; 165 166 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK; 167 msg->version = 0; 168 msg->outsize = 0; 169 msg->insize = sizeof(*r); 170 171 ret = send_command(ec_dev, msg); 172 if (ret > 0) { 173 r = (struct ec_response_host_event_mask *)msg->data; 174 *mask = r->mask; 175 } 176 177 return ret; 178 } 179 180 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev, 181 int devidx, 182 struct cros_ec_command *msg) 183 { 184 /* 185 * Try using v3+ to query for supported protocols. If this 186 * command fails, fall back to v2. Returns the highest protocol 187 * supported by the EC. 188 * Also sets the max request/response/passthru size. 189 */ 190 int ret; 191 192 if (!ec_dev->pkt_xfer) 193 return -EPROTONOSUPPORT; 194 195 memset(msg, 0, sizeof(*msg)); 196 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO; 197 msg->insize = sizeof(struct ec_response_get_protocol_info); 198 199 ret = send_command(ec_dev, msg); 200 201 if (ret < 0) { 202 dev_dbg(ec_dev->dev, 203 "failed to check for EC[%d] protocol version: %d\n", 204 devidx, ret); 205 return ret; 206 } 207 208 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND) 209 return -ENODEV; 210 else if (msg->result != EC_RES_SUCCESS) 211 return msg->result; 212 213 return 0; 214 } 215 216 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev) 217 { 218 struct cros_ec_command *msg; 219 struct ec_params_hello *hello_params; 220 struct ec_response_hello *hello_response; 221 int ret; 222 int len = max(sizeof(*hello_params), sizeof(*hello_response)); 223 224 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL); 225 if (!msg) 226 return -ENOMEM; 227 228 msg->version = 0; 229 msg->command = EC_CMD_HELLO; 230 hello_params = (struct ec_params_hello *)msg->data; 231 msg->outsize = sizeof(*hello_params); 232 hello_response = (struct ec_response_hello *)msg->data; 233 msg->insize = sizeof(*hello_response); 234 235 hello_params->in_data = 0xa0b0c0d0; 236 237 ret = send_command(ec_dev, msg); 238 239 if (ret < 0) { 240 dev_dbg(ec_dev->dev, 241 "EC failed to respond to v2 hello: %d\n", 242 ret); 243 goto exit; 244 } else if (msg->result != EC_RES_SUCCESS) { 245 dev_err(ec_dev->dev, 246 "EC responded to v2 hello with error: %d\n", 247 msg->result); 248 ret = msg->result; 249 goto exit; 250 } else if (hello_response->out_data != 0xa1b2c3d4) { 251 dev_err(ec_dev->dev, 252 "EC responded to v2 hello with bad result: %u\n", 253 hello_response->out_data); 254 ret = -EBADMSG; 255 goto exit; 256 } 257 258 ret = 0; 259 260 exit: 261 kfree(msg); 262 return ret; 263 } 264 265 /* 266 * cros_ec_get_host_command_version_mask 267 * 268 * Get the version mask of a given command. 269 * 270 * @ec_dev: EC device to call 271 * @msg: message structure to use 272 * @cmd: command to get the version of. 273 * @mask: result when function returns 0. 274 * 275 * @return 0 on success, error code otherwise 276 * 277 * LOCKING: 278 * the caller has ec_dev->lock mutex or the caller knows there is 279 * no other command in progress. 280 */ 281 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev, 282 u16 cmd, u32 *mask) 283 { 284 struct ec_params_get_cmd_versions *pver; 285 struct ec_response_get_cmd_versions *rver; 286 struct cros_ec_command *msg; 287 int ret; 288 289 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)), 290 GFP_KERNEL); 291 if (!msg) 292 return -ENOMEM; 293 294 msg->version = 0; 295 msg->command = EC_CMD_GET_CMD_VERSIONS; 296 msg->insize = sizeof(*rver); 297 msg->outsize = sizeof(*pver); 298 299 pver = (struct ec_params_get_cmd_versions *)msg->data; 300 pver->cmd = cmd; 301 302 ret = send_command(ec_dev, msg); 303 if (ret > 0) { 304 rver = (struct ec_response_get_cmd_versions *)msg->data; 305 *mask = rver->version_mask; 306 } 307 308 kfree(msg); 309 310 return ret; 311 } 312 313 int cros_ec_query_all(struct cros_ec_device *ec_dev) 314 { 315 struct device *dev = ec_dev->dev; 316 struct cros_ec_command *proto_msg; 317 struct ec_response_get_protocol_info *proto_info; 318 u32 ver_mask = 0; 319 int ret; 320 321 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info), 322 GFP_KERNEL); 323 if (!proto_msg) 324 return -ENOMEM; 325 326 /* First try sending with proto v3. */ 327 ec_dev->proto_version = 3; 328 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg); 329 330 if (ret == 0) { 331 proto_info = (struct ec_response_get_protocol_info *) 332 proto_msg->data; 333 ec_dev->max_request = proto_info->max_request_packet_size - 334 sizeof(struct ec_host_request); 335 ec_dev->max_response = proto_info->max_response_packet_size - 336 sizeof(struct ec_host_response); 337 ec_dev->proto_version = 338 min(EC_HOST_REQUEST_VERSION, 339 fls(proto_info->protocol_versions) - 1); 340 dev_dbg(ec_dev->dev, 341 "using proto v%u\n", 342 ec_dev->proto_version); 343 344 ec_dev->din_size = ec_dev->max_response + 345 sizeof(struct ec_host_response) + 346 EC_MAX_RESPONSE_OVERHEAD; 347 ec_dev->dout_size = ec_dev->max_request + 348 sizeof(struct ec_host_request) + 349 EC_MAX_REQUEST_OVERHEAD; 350 351 /* 352 * Check for PD 353 */ 354 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg); 355 356 if (ret) { 357 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret); 358 ec_dev->max_passthru = 0; 359 } else { 360 dev_dbg(ec_dev->dev, "found PD chip\n"); 361 ec_dev->max_passthru = 362 proto_info->max_request_packet_size - 363 sizeof(struct ec_host_request); 364 } 365 } else { 366 /* Try querying with a v2 hello message. */ 367 ec_dev->proto_version = 2; 368 ret = cros_ec_host_command_proto_query_v2(ec_dev); 369 370 if (ret == 0) { 371 /* V2 hello succeeded. */ 372 dev_dbg(ec_dev->dev, "falling back to proto v2\n"); 373 374 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE; 375 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE; 376 ec_dev->max_passthru = 0; 377 ec_dev->pkt_xfer = NULL; 378 ec_dev->din_size = EC_PROTO2_MSG_BYTES; 379 ec_dev->dout_size = EC_PROTO2_MSG_BYTES; 380 } else { 381 /* 382 * It's possible for a test to occur too early when 383 * the EC isn't listening. If this happens, we'll 384 * test later when the first command is run. 385 */ 386 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN; 387 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret); 388 goto exit; 389 } 390 } 391 392 devm_kfree(dev, ec_dev->din); 393 devm_kfree(dev, ec_dev->dout); 394 395 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL); 396 if (!ec_dev->din) { 397 ret = -ENOMEM; 398 goto exit; 399 } 400 401 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL); 402 if (!ec_dev->dout) { 403 devm_kfree(dev, ec_dev->din); 404 ret = -ENOMEM; 405 goto exit; 406 } 407 408 /* Probe if MKBP event is supported */ 409 ret = cros_ec_get_host_command_version_mask(ec_dev, 410 EC_CMD_GET_NEXT_EVENT, 411 &ver_mask); 412 if (ret < 0 || ver_mask == 0) 413 ec_dev->mkbp_event_supported = 0; 414 else 415 ec_dev->mkbp_event_supported = 1; 416 417 /* 418 * Get host event wake mask, assume all events are wake events 419 * if unavailable. 420 */ 421 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg, 422 &ec_dev->host_event_wake_mask); 423 if (ret < 0) 424 ec_dev->host_event_wake_mask = U32_MAX; 425 426 ret = 0; 427 428 exit: 429 kfree(proto_msg); 430 return ret; 431 } 432 EXPORT_SYMBOL(cros_ec_query_all); 433 434 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, 435 struct cros_ec_command *msg) 436 { 437 int ret; 438 439 mutex_lock(&ec_dev->lock); 440 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) { 441 ret = cros_ec_query_all(ec_dev); 442 if (ret) { 443 dev_err(ec_dev->dev, 444 "EC version unknown and query failed; aborting command\n"); 445 mutex_unlock(&ec_dev->lock); 446 return ret; 447 } 448 } 449 450 if (msg->insize > ec_dev->max_response) { 451 dev_dbg(ec_dev->dev, "clamping message receive buffer\n"); 452 msg->insize = ec_dev->max_response; 453 } 454 455 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) { 456 if (msg->outsize > ec_dev->max_request) { 457 dev_err(ec_dev->dev, 458 "request of size %u is too big (max: %u)\n", 459 msg->outsize, 460 ec_dev->max_request); 461 mutex_unlock(&ec_dev->lock); 462 return -EMSGSIZE; 463 } 464 } else { 465 if (msg->outsize > ec_dev->max_passthru) { 466 dev_err(ec_dev->dev, 467 "passthru rq of size %u is too big (max: %u)\n", 468 msg->outsize, 469 ec_dev->max_passthru); 470 mutex_unlock(&ec_dev->lock); 471 return -EMSGSIZE; 472 } 473 } 474 ret = send_command(ec_dev, msg); 475 mutex_unlock(&ec_dev->lock); 476 477 return ret; 478 } 479 EXPORT_SYMBOL(cros_ec_cmd_xfer); 480 481 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev, 482 struct cros_ec_command *msg) 483 { 484 int ret; 485 486 ret = cros_ec_cmd_xfer(ec_dev, msg); 487 if (ret < 0) { 488 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret); 489 } else if (msg->result != EC_RES_SUCCESS) { 490 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result); 491 return -EPROTO; 492 } 493 494 return ret; 495 } 496 EXPORT_SYMBOL(cros_ec_cmd_xfer_status); 497 498 static int get_next_event_xfer(struct cros_ec_device *ec_dev, 499 struct cros_ec_command *msg, 500 int version, uint32_t size) 501 { 502 int ret; 503 504 msg->version = version; 505 msg->command = EC_CMD_GET_NEXT_EVENT; 506 msg->insize = size; 507 msg->outsize = 0; 508 509 ret = cros_ec_cmd_xfer(ec_dev, msg); 510 if (ret > 0) { 511 ec_dev->event_size = ret - 1; 512 memcpy(&ec_dev->event_data, msg->data, ret); 513 } 514 515 return ret; 516 } 517 518 static int get_next_event(struct cros_ec_device *ec_dev) 519 { 520 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)]; 521 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; 522 static int cmd_version = 1; 523 int ret; 524 525 if (ec_dev->suspended) { 526 dev_dbg(ec_dev->dev, "Device suspended.\n"); 527 return -EHOSTDOWN; 528 } 529 530 if (cmd_version == 1) { 531 ret = get_next_event_xfer(ec_dev, msg, cmd_version, 532 sizeof(struct ec_response_get_next_event_v1)); 533 if (ret < 0 || msg->result != EC_RES_INVALID_VERSION) 534 return ret; 535 536 /* Fallback to version 0 for future send attempts */ 537 cmd_version = 0; 538 } 539 540 ret = get_next_event_xfer(ec_dev, msg, cmd_version, 541 sizeof(struct ec_response_get_next_event)); 542 543 return ret; 544 } 545 546 static int get_keyboard_state_event(struct cros_ec_device *ec_dev) 547 { 548 u8 buffer[sizeof(struct cros_ec_command) + 549 sizeof(ec_dev->event_data.data)]; 550 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; 551 552 msg->version = 0; 553 msg->command = EC_CMD_MKBP_STATE; 554 msg->insize = sizeof(ec_dev->event_data.data); 555 msg->outsize = 0; 556 557 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg); 558 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX; 559 memcpy(&ec_dev->event_data.data, msg->data, 560 sizeof(ec_dev->event_data.data)); 561 562 return ec_dev->event_size; 563 } 564 565 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event) 566 { 567 u8 event_type; 568 u32 host_event; 569 int ret; 570 571 if (!ec_dev->mkbp_event_supported) { 572 ret = get_keyboard_state_event(ec_dev); 573 if (ret <= 0) 574 return ret; 575 576 if (wake_event) 577 *wake_event = true; 578 579 return ret; 580 } 581 582 ret = get_next_event(ec_dev); 583 if (ret <= 0) 584 return ret; 585 586 if (wake_event) { 587 event_type = ec_dev->event_data.event_type; 588 host_event = cros_ec_get_host_event(ec_dev); 589 590 /* 591 * Sensor events need to be parsed by the sensor sub-device. 592 * Defer them, and don't report the wakeup here. 593 */ 594 if (event_type == EC_MKBP_EVENT_SENSOR_FIFO) 595 *wake_event = false; 596 /* Masked host-events should not count as wake events. */ 597 else if (host_event && 598 !(host_event & ec_dev->host_event_wake_mask)) 599 *wake_event = false; 600 /* Consider all other events as wake events. */ 601 else 602 *wake_event = true; 603 } 604 605 return ret; 606 } 607 EXPORT_SYMBOL(cros_ec_get_next_event); 608 609 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev) 610 { 611 u32 host_event; 612 613 BUG_ON(!ec_dev->mkbp_event_supported); 614 615 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT) 616 return 0; 617 618 if (ec_dev->event_size != sizeof(host_event)) { 619 dev_warn(ec_dev->dev, "Invalid host event size\n"); 620 return 0; 621 } 622 623 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event); 624 625 return host_event; 626 } 627 EXPORT_SYMBOL(cros_ec_get_host_event); 628