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/delay.h> 7 #include <linux/device.h> 8 #include <linux/module.h> 9 #include <linux/platform_data/cros_ec_commands.h> 10 #include <linux/platform_data/cros_ec_proto.h> 11 #include <linux/slab.h> 12 #include <asm/unaligned.h> 13 14 #include "cros_ec_trace.h" 15 16 #define EC_COMMAND_RETRIES 50 17 18 static int prepare_packet(struct cros_ec_device *ec_dev, 19 struct cros_ec_command *msg) 20 { 21 struct ec_host_request *request; 22 u8 *out; 23 int i; 24 u8 csum = 0; 25 26 BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION); 27 BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size); 28 29 out = ec_dev->dout; 30 request = (struct ec_host_request *)out; 31 request->struct_version = EC_HOST_REQUEST_VERSION; 32 request->checksum = 0; 33 request->command = msg->command; 34 request->command_version = msg->version; 35 request->reserved = 0; 36 request->data_len = msg->outsize; 37 38 for (i = 0; i < sizeof(*request); i++) 39 csum += out[i]; 40 41 /* Copy data and update checksum */ 42 memcpy(out + sizeof(*request), msg->data, msg->outsize); 43 for (i = 0; i < msg->outsize; i++) 44 csum += msg->data[i]; 45 46 request->checksum = -csum; 47 48 return sizeof(*request) + msg->outsize; 49 } 50 51 static int send_command(struct cros_ec_device *ec_dev, 52 struct cros_ec_command *msg) 53 { 54 int ret; 55 int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg); 56 57 trace_cros_ec_cmd(msg); 58 59 if (ec_dev->proto_version > 2) 60 xfer_fxn = ec_dev->pkt_xfer; 61 else 62 xfer_fxn = ec_dev->cmd_xfer; 63 64 if (!xfer_fxn) { 65 /* 66 * This error can happen if a communication error happened and 67 * the EC is trying to use protocol v2, on an underlying 68 * communication mechanism that does not support v2. 69 */ 70 dev_err_once(ec_dev->dev, 71 "missing EC transfer API, cannot send command\n"); 72 return -EIO; 73 } 74 75 ret = (*xfer_fxn)(ec_dev, msg); 76 if (msg->result == EC_RES_IN_PROGRESS) { 77 int i; 78 struct cros_ec_command *status_msg; 79 struct ec_response_get_comms_status *status; 80 81 status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status), 82 GFP_KERNEL); 83 if (!status_msg) 84 return -ENOMEM; 85 86 status_msg->version = 0; 87 status_msg->command = EC_CMD_GET_COMMS_STATUS; 88 status_msg->insize = sizeof(*status); 89 status_msg->outsize = 0; 90 91 /* 92 * Query the EC's status until it's no longer busy or 93 * we encounter an error. 94 */ 95 for (i = 0; i < EC_COMMAND_RETRIES; i++) { 96 usleep_range(10000, 11000); 97 98 ret = (*xfer_fxn)(ec_dev, status_msg); 99 if (ret == -EAGAIN) 100 continue; 101 if (ret < 0) 102 break; 103 104 msg->result = status_msg->result; 105 if (status_msg->result != EC_RES_SUCCESS) 106 break; 107 108 status = (struct ec_response_get_comms_status *) 109 status_msg->data; 110 if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) 111 break; 112 } 113 114 kfree(status_msg); 115 } 116 117 return ret; 118 } 119 120 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, 121 struct cros_ec_command *msg) 122 { 123 u8 *out; 124 u8 csum; 125 int i; 126 127 if (ec_dev->proto_version > 2) 128 return prepare_packet(ec_dev, msg); 129 130 BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE); 131 out = ec_dev->dout; 132 out[0] = EC_CMD_VERSION0 + msg->version; 133 out[1] = msg->command; 134 out[2] = msg->outsize; 135 csum = out[0] + out[1] + out[2]; 136 for (i = 0; i < msg->outsize; i++) 137 csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i]; 138 out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum; 139 140 return EC_MSG_TX_PROTO_BYTES + msg->outsize; 141 } 142 EXPORT_SYMBOL(cros_ec_prepare_tx); 143 144 int cros_ec_check_result(struct cros_ec_device *ec_dev, 145 struct cros_ec_command *msg) 146 { 147 switch (msg->result) { 148 case EC_RES_SUCCESS: 149 return 0; 150 case EC_RES_IN_PROGRESS: 151 dev_dbg(ec_dev->dev, "command 0x%02x in progress\n", 152 msg->command); 153 return -EAGAIN; 154 default: 155 dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n", 156 msg->command, msg->result); 157 return 0; 158 } 159 } 160 EXPORT_SYMBOL(cros_ec_check_result); 161 162 /* 163 * cros_ec_get_host_event_wake_mask 164 * 165 * Get the mask of host events that cause wake from suspend. 166 * 167 * @ec_dev: EC device to call 168 * @msg: message structure to use 169 * @mask: result when function returns >=0. 170 * 171 * LOCKING: 172 * the caller has ec_dev->lock mutex, or the caller knows there is 173 * no other command in progress. 174 */ 175 static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev, 176 struct cros_ec_command *msg, 177 uint32_t *mask) 178 { 179 struct ec_response_host_event_mask *r; 180 int ret; 181 182 msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK; 183 msg->version = 0; 184 msg->outsize = 0; 185 msg->insize = sizeof(*r); 186 187 ret = send_command(ec_dev, msg); 188 if (ret > 0) { 189 r = (struct ec_response_host_event_mask *)msg->data; 190 *mask = r->mask; 191 } 192 193 return ret; 194 } 195 196 static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev, 197 int devidx, 198 struct cros_ec_command *msg) 199 { 200 /* 201 * Try using v3+ to query for supported protocols. If this 202 * command fails, fall back to v2. Returns the highest protocol 203 * supported by the EC. 204 * Also sets the max request/response/passthru size. 205 */ 206 int ret; 207 208 if (!ec_dev->pkt_xfer) 209 return -EPROTONOSUPPORT; 210 211 memset(msg, 0, sizeof(*msg)); 212 msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO; 213 msg->insize = sizeof(struct ec_response_get_protocol_info); 214 215 ret = send_command(ec_dev, msg); 216 217 if (ret < 0) { 218 dev_dbg(ec_dev->dev, 219 "failed to check for EC[%d] protocol version: %d\n", 220 devidx, ret); 221 return ret; 222 } 223 224 if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND) 225 return -ENODEV; 226 else if (msg->result != EC_RES_SUCCESS) 227 return msg->result; 228 229 return 0; 230 } 231 232 static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev) 233 { 234 struct cros_ec_command *msg; 235 struct ec_params_hello *hello_params; 236 struct ec_response_hello *hello_response; 237 int ret; 238 int len = max(sizeof(*hello_params), sizeof(*hello_response)); 239 240 msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL); 241 if (!msg) 242 return -ENOMEM; 243 244 msg->version = 0; 245 msg->command = EC_CMD_HELLO; 246 hello_params = (struct ec_params_hello *)msg->data; 247 msg->outsize = sizeof(*hello_params); 248 hello_response = (struct ec_response_hello *)msg->data; 249 msg->insize = sizeof(*hello_response); 250 251 hello_params->in_data = 0xa0b0c0d0; 252 253 ret = send_command(ec_dev, msg); 254 255 if (ret < 0) { 256 dev_dbg(ec_dev->dev, 257 "EC failed to respond to v2 hello: %d\n", 258 ret); 259 goto exit; 260 } else if (msg->result != EC_RES_SUCCESS) { 261 dev_err(ec_dev->dev, 262 "EC responded to v2 hello with error: %d\n", 263 msg->result); 264 ret = msg->result; 265 goto exit; 266 } else if (hello_response->out_data != 0xa1b2c3d4) { 267 dev_err(ec_dev->dev, 268 "EC responded to v2 hello with bad result: %u\n", 269 hello_response->out_data); 270 ret = -EBADMSG; 271 goto exit; 272 } 273 274 ret = 0; 275 276 exit: 277 kfree(msg); 278 return ret; 279 } 280 281 /* 282 * cros_ec_get_host_command_version_mask 283 * 284 * Get the version mask of a given command. 285 * 286 * @ec_dev: EC device to call 287 * @msg: message structure to use 288 * @cmd: command to get the version of. 289 * @mask: result when function returns 0. 290 * 291 * @return 0 on success, error code otherwise 292 * 293 * LOCKING: 294 * the caller has ec_dev->lock mutex or the caller knows there is 295 * no other command in progress. 296 */ 297 static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev, 298 u16 cmd, u32 *mask) 299 { 300 struct ec_params_get_cmd_versions *pver; 301 struct ec_response_get_cmd_versions *rver; 302 struct cros_ec_command *msg; 303 int ret; 304 305 msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)), 306 GFP_KERNEL); 307 if (!msg) 308 return -ENOMEM; 309 310 msg->version = 0; 311 msg->command = EC_CMD_GET_CMD_VERSIONS; 312 msg->insize = sizeof(*rver); 313 msg->outsize = sizeof(*pver); 314 315 pver = (struct ec_params_get_cmd_versions *)msg->data; 316 pver->cmd = cmd; 317 318 ret = send_command(ec_dev, msg); 319 if (ret > 0) { 320 rver = (struct ec_response_get_cmd_versions *)msg->data; 321 *mask = rver->version_mask; 322 } 323 324 kfree(msg); 325 326 return ret; 327 } 328 329 int cros_ec_query_all(struct cros_ec_device *ec_dev) 330 { 331 struct device *dev = ec_dev->dev; 332 struct cros_ec_command *proto_msg; 333 struct ec_response_get_protocol_info *proto_info; 334 u32 ver_mask = 0; 335 int ret; 336 337 proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info), 338 GFP_KERNEL); 339 if (!proto_msg) 340 return -ENOMEM; 341 342 /* First try sending with proto v3. */ 343 ec_dev->proto_version = 3; 344 ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg); 345 346 if (ret == 0) { 347 proto_info = (struct ec_response_get_protocol_info *) 348 proto_msg->data; 349 ec_dev->max_request = proto_info->max_request_packet_size - 350 sizeof(struct ec_host_request); 351 ec_dev->max_response = proto_info->max_response_packet_size - 352 sizeof(struct ec_host_response); 353 ec_dev->proto_version = 354 min(EC_HOST_REQUEST_VERSION, 355 fls(proto_info->protocol_versions) - 1); 356 dev_dbg(ec_dev->dev, 357 "using proto v%u\n", 358 ec_dev->proto_version); 359 360 ec_dev->din_size = ec_dev->max_response + 361 sizeof(struct ec_host_response) + 362 EC_MAX_RESPONSE_OVERHEAD; 363 ec_dev->dout_size = ec_dev->max_request + 364 sizeof(struct ec_host_request) + 365 EC_MAX_REQUEST_OVERHEAD; 366 367 /* 368 * Check for PD 369 */ 370 ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg); 371 372 if (ret) { 373 dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret); 374 ec_dev->max_passthru = 0; 375 } else { 376 dev_dbg(ec_dev->dev, "found PD chip\n"); 377 ec_dev->max_passthru = 378 proto_info->max_request_packet_size - 379 sizeof(struct ec_host_request); 380 } 381 } else { 382 /* Try querying with a v2 hello message. */ 383 ec_dev->proto_version = 2; 384 ret = cros_ec_host_command_proto_query_v2(ec_dev); 385 386 if (ret == 0) { 387 /* V2 hello succeeded. */ 388 dev_dbg(ec_dev->dev, "falling back to proto v2\n"); 389 390 ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE; 391 ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE; 392 ec_dev->max_passthru = 0; 393 ec_dev->pkt_xfer = NULL; 394 ec_dev->din_size = EC_PROTO2_MSG_BYTES; 395 ec_dev->dout_size = EC_PROTO2_MSG_BYTES; 396 } else { 397 /* 398 * It's possible for a test to occur too early when 399 * the EC isn't listening. If this happens, we'll 400 * test later when the first command is run. 401 */ 402 ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN; 403 dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret); 404 goto exit; 405 } 406 } 407 408 devm_kfree(dev, ec_dev->din); 409 devm_kfree(dev, ec_dev->dout); 410 411 ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL); 412 if (!ec_dev->din) { 413 ret = -ENOMEM; 414 goto exit; 415 } 416 417 ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL); 418 if (!ec_dev->dout) { 419 devm_kfree(dev, ec_dev->din); 420 ret = -ENOMEM; 421 goto exit; 422 } 423 424 /* Probe if MKBP event is supported */ 425 ret = cros_ec_get_host_command_version_mask(ec_dev, 426 EC_CMD_GET_NEXT_EVENT, 427 &ver_mask); 428 if (ret < 0 || ver_mask == 0) 429 ec_dev->mkbp_event_supported = 0; 430 else 431 ec_dev->mkbp_event_supported = 1; 432 433 /* Probe if host sleep v1 is supported for S0ix failure detection. */ 434 ret = cros_ec_get_host_command_version_mask(ec_dev, 435 EC_CMD_HOST_SLEEP_EVENT, 436 &ver_mask); 437 ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(1))); 438 439 /* 440 * Get host event wake mask, assume all events are wake events 441 * if unavailable. 442 */ 443 ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg, 444 &ec_dev->host_event_wake_mask); 445 if (ret < 0) 446 ec_dev->host_event_wake_mask = U32_MAX; 447 448 ret = 0; 449 450 exit: 451 kfree(proto_msg); 452 return ret; 453 } 454 EXPORT_SYMBOL(cros_ec_query_all); 455 456 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, 457 struct cros_ec_command *msg) 458 { 459 int ret; 460 461 mutex_lock(&ec_dev->lock); 462 if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) { 463 ret = cros_ec_query_all(ec_dev); 464 if (ret) { 465 dev_err(ec_dev->dev, 466 "EC version unknown and query failed; aborting command\n"); 467 mutex_unlock(&ec_dev->lock); 468 return ret; 469 } 470 } 471 472 if (msg->insize > ec_dev->max_response) { 473 dev_dbg(ec_dev->dev, "clamping message receive buffer\n"); 474 msg->insize = ec_dev->max_response; 475 } 476 477 if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) { 478 if (msg->outsize > ec_dev->max_request) { 479 dev_err(ec_dev->dev, 480 "request of size %u is too big (max: %u)\n", 481 msg->outsize, 482 ec_dev->max_request); 483 mutex_unlock(&ec_dev->lock); 484 return -EMSGSIZE; 485 } 486 } else { 487 if (msg->outsize > ec_dev->max_passthru) { 488 dev_err(ec_dev->dev, 489 "passthru rq of size %u is too big (max: %u)\n", 490 msg->outsize, 491 ec_dev->max_passthru); 492 mutex_unlock(&ec_dev->lock); 493 return -EMSGSIZE; 494 } 495 } 496 ret = send_command(ec_dev, msg); 497 mutex_unlock(&ec_dev->lock); 498 499 return ret; 500 } 501 EXPORT_SYMBOL(cros_ec_cmd_xfer); 502 503 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev, 504 struct cros_ec_command *msg) 505 { 506 int ret; 507 508 ret = cros_ec_cmd_xfer(ec_dev, msg); 509 if (ret < 0) { 510 dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret); 511 } else if (msg->result != EC_RES_SUCCESS) { 512 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result); 513 return -EPROTO; 514 } 515 516 return ret; 517 } 518 EXPORT_SYMBOL(cros_ec_cmd_xfer_status); 519 520 static int get_next_event_xfer(struct cros_ec_device *ec_dev, 521 struct cros_ec_command *msg, 522 int version, uint32_t size) 523 { 524 int ret; 525 526 msg->version = version; 527 msg->command = EC_CMD_GET_NEXT_EVENT; 528 msg->insize = size; 529 msg->outsize = 0; 530 531 ret = cros_ec_cmd_xfer(ec_dev, msg); 532 if (ret > 0) { 533 ec_dev->event_size = ret - 1; 534 memcpy(&ec_dev->event_data, msg->data, ret); 535 } 536 537 return ret; 538 } 539 540 static int get_next_event(struct cros_ec_device *ec_dev) 541 { 542 u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)]; 543 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; 544 static int cmd_version = 1; 545 int ret; 546 547 if (ec_dev->suspended) { 548 dev_dbg(ec_dev->dev, "Device suspended.\n"); 549 return -EHOSTDOWN; 550 } 551 552 if (cmd_version == 1) { 553 ret = get_next_event_xfer(ec_dev, msg, cmd_version, 554 sizeof(struct ec_response_get_next_event_v1)); 555 if (ret < 0 || msg->result != EC_RES_INVALID_VERSION) 556 return ret; 557 558 /* Fallback to version 0 for future send attempts */ 559 cmd_version = 0; 560 } 561 562 ret = get_next_event_xfer(ec_dev, msg, cmd_version, 563 sizeof(struct ec_response_get_next_event)); 564 565 return ret; 566 } 567 568 static int get_keyboard_state_event(struct cros_ec_device *ec_dev) 569 { 570 u8 buffer[sizeof(struct cros_ec_command) + 571 sizeof(ec_dev->event_data.data)]; 572 struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; 573 574 msg->version = 0; 575 msg->command = EC_CMD_MKBP_STATE; 576 msg->insize = sizeof(ec_dev->event_data.data); 577 msg->outsize = 0; 578 579 ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg); 580 ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX; 581 memcpy(&ec_dev->event_data.data, msg->data, 582 sizeof(ec_dev->event_data.data)); 583 584 return ec_dev->event_size; 585 } 586 587 int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event) 588 { 589 u8 event_type; 590 u32 host_event; 591 int ret; 592 593 if (!ec_dev->mkbp_event_supported) { 594 ret = get_keyboard_state_event(ec_dev); 595 if (ret <= 0) 596 return ret; 597 598 if (wake_event) 599 *wake_event = true; 600 601 return ret; 602 } 603 604 ret = get_next_event(ec_dev); 605 if (ret <= 0) 606 return ret; 607 608 if (wake_event) { 609 event_type = ec_dev->event_data.event_type; 610 host_event = cros_ec_get_host_event(ec_dev); 611 612 /* 613 * Sensor events need to be parsed by the sensor sub-device. 614 * Defer them, and don't report the wakeup here. 615 */ 616 if (event_type == EC_MKBP_EVENT_SENSOR_FIFO) 617 *wake_event = false; 618 /* Masked host-events should not count as wake events. */ 619 else if (host_event && 620 !(host_event & ec_dev->host_event_wake_mask)) 621 *wake_event = false; 622 /* Consider all other events as wake events. */ 623 else 624 *wake_event = true; 625 } 626 627 return ret; 628 } 629 EXPORT_SYMBOL(cros_ec_get_next_event); 630 631 u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev) 632 { 633 u32 host_event; 634 635 BUG_ON(!ec_dev->mkbp_event_supported); 636 637 if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT) 638 return 0; 639 640 if (ec_dev->event_size != sizeof(host_event)) { 641 dev_warn(ec_dev->dev, "Invalid host event size\n"); 642 return 0; 643 } 644 645 host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event); 646 647 return host_event; 648 } 649 EXPORT_SYMBOL(cros_ec_get_host_event); 650