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