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