drivers/platform/chrome/cros_ec_proto.c

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