1 // SPDX-License-Identifier: GPL-2.0 2 // LPC interface for ChromeOS Embedded Controller 3 // 4 // Copyright (C) 2012-2015 Google, Inc 5 // 6 // This driver uses the ChromeOS EC byte-level message-based protocol for 7 // communicating the keyboard state (which keys are pressed) from a keyboard EC 8 // to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing, 9 // but everything else (including deghosting) is done here. The main 10 // motivation for this is to keep the EC firmware as simple as possible, since 11 // it cannot be easily upgraded and EC flash/IRAM space is relatively 12 // expensive. 13 14 #include <linux/acpi.h> 15 #include <linux/dmi.h> 16 #include <linux/delay.h> 17 #include <linux/io.h> 18 #include <linux/interrupt.h> 19 #include <linux/kobject.h> 20 #include <linux/module.h> 21 #include <linux/platform_data/cros_ec_commands.h> 22 #include <linux/platform_data/cros_ec_proto.h> 23 #include <linux/platform_device.h> 24 #include <linux/printk.h> 25 #include <linux/reboot.h> 26 #include <linux/suspend.h> 27 28 #include "cros_ec.h" 29 #include "cros_ec_lpc_mec.h" 30 31 #define DRV_NAME "cros_ec_lpcs" 32 #define ACPI_DRV_NAME "GOOG0004" 33 34 /* True if ACPI device is present */ 35 static bool cros_ec_lpc_acpi_device_found; 36 37 /** 38 * struct lpc_driver_ops - LPC driver operations 39 * @read: Copy length bytes from EC address offset into buffer dest. Returns 40 * the 8-bit checksum of all bytes read. 41 * @write: Copy length bytes from buffer msg into EC address offset. Returns 42 * the 8-bit checksum of all bytes written. 43 */ 44 struct lpc_driver_ops { 45 u8 (*read)(unsigned int offset, unsigned int length, u8 *dest); 46 u8 (*write)(unsigned int offset, unsigned int length, const u8 *msg); 47 }; 48 49 static struct lpc_driver_ops cros_ec_lpc_ops = { }; 50 51 /* 52 * A generic instance of the read function of struct lpc_driver_ops, used for 53 * the LPC EC. 54 */ 55 static u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, 56 u8 *dest) 57 { 58 int sum = 0; 59 int i; 60 61 for (i = 0; i < length; ++i) { 62 dest[i] = inb(offset + i); 63 sum += dest[i]; 64 } 65 66 /* Return checksum of all bytes read */ 67 return sum; 68 } 69 70 /* 71 * A generic instance of the write function of struct lpc_driver_ops, used for 72 * the LPC EC. 73 */ 74 static u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, 75 const u8 *msg) 76 { 77 int sum = 0; 78 int i; 79 80 for (i = 0; i < length; ++i) { 81 outb(msg[i], offset + i); 82 sum += msg[i]; 83 } 84 85 /* Return checksum of all bytes written */ 86 return sum; 87 } 88 89 /* 90 * An instance of the read function of struct lpc_driver_ops, used for the 91 * MEC variant of LPC EC. 92 */ 93 static u8 cros_ec_lpc_mec_read_bytes(unsigned int offset, unsigned int length, 94 u8 *dest) 95 { 96 int in_range = cros_ec_lpc_mec_in_range(offset, length); 97 98 if (in_range < 0) 99 return 0; 100 101 return in_range ? 102 cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 103 offset - EC_HOST_CMD_REGION0, 104 length, dest) : 105 cros_ec_lpc_read_bytes(offset, length, dest); 106 } 107 108 /* 109 * An instance of the write function of struct lpc_driver_ops, used for the 110 * MEC variant of LPC EC. 111 */ 112 static u8 cros_ec_lpc_mec_write_bytes(unsigned int offset, unsigned int length, 113 const u8 *msg) 114 { 115 int in_range = cros_ec_lpc_mec_in_range(offset, length); 116 117 if (in_range < 0) 118 return 0; 119 120 return in_range ? 121 cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 122 offset - EC_HOST_CMD_REGION0, 123 length, (u8 *)msg) : 124 cros_ec_lpc_write_bytes(offset, length, msg); 125 } 126 127 static int ec_response_timed_out(void) 128 { 129 unsigned long one_second = jiffies + HZ; 130 u8 data; 131 132 usleep_range(200, 300); 133 do { 134 if (!(cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_CMD, 1, &data) & 135 EC_LPC_STATUS_BUSY_MASK)) 136 return 0; 137 usleep_range(100, 200); 138 } while (time_before(jiffies, one_second)); 139 140 return 1; 141 } 142 143 static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec, 144 struct cros_ec_command *msg) 145 { 146 struct ec_host_response response; 147 u8 sum; 148 int ret = 0; 149 u8 *dout; 150 151 ret = cros_ec_prepare_tx(ec, msg); 152 if (ret < 0) 153 goto done; 154 155 /* Write buffer */ 156 cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout); 157 158 /* Here we go */ 159 sum = EC_COMMAND_PROTOCOL_3; 160 cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum); 161 162 if (ec_response_timed_out()) { 163 dev_warn(ec->dev, "EC response timed out\n"); 164 ret = -EIO; 165 goto done; 166 } 167 168 /* Check result */ 169 msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum); 170 ret = cros_ec_check_result(ec, msg); 171 if (ret) 172 goto done; 173 174 /* Read back response */ 175 dout = (u8 *)&response; 176 sum = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET, sizeof(response), 177 dout); 178 179 msg->result = response.result; 180 181 if (response.data_len > msg->insize) { 182 dev_err(ec->dev, 183 "packet too long (%d bytes, expected %d)", 184 response.data_len, msg->insize); 185 ret = -EMSGSIZE; 186 goto done; 187 } 188 189 /* Read response and process checksum */ 190 sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PACKET + 191 sizeof(response), response.data_len, 192 msg->data); 193 194 if (sum) { 195 dev_err(ec->dev, 196 "bad packet checksum %02x\n", 197 response.checksum); 198 ret = -EBADMSG; 199 goto done; 200 } 201 202 /* Return actual amount of data received */ 203 ret = response.data_len; 204 done: 205 return ret; 206 } 207 208 static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec, 209 struct cros_ec_command *msg) 210 { 211 struct ec_lpc_host_args args; 212 u8 sum; 213 int ret = 0; 214 215 if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE || 216 msg->insize > EC_PROTO2_MAX_PARAM_SIZE) { 217 dev_err(ec->dev, 218 "invalid buffer sizes (out %d, in %d)\n", 219 msg->outsize, msg->insize); 220 return -EINVAL; 221 } 222 223 /* Now actually send the command to the EC and get the result */ 224 args.flags = EC_HOST_ARGS_FLAG_FROM_HOST; 225 args.command_version = msg->version; 226 args.data_size = msg->outsize; 227 228 /* Initialize checksum */ 229 sum = msg->command + args.flags + args.command_version + args.data_size; 230 231 /* Copy data and update checksum */ 232 sum += cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_PARAM, msg->outsize, 233 msg->data); 234 235 /* Finalize checksum and write args */ 236 args.checksum = sum; 237 cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_ARGS, sizeof(args), 238 (u8 *)&args); 239 240 /* Here we go */ 241 sum = msg->command; 242 cros_ec_lpc_ops.write(EC_LPC_ADDR_HOST_CMD, 1, &sum); 243 244 if (ec_response_timed_out()) { 245 dev_warn(ec->dev, "EC response timed out\n"); 246 ret = -EIO; 247 goto done; 248 } 249 250 /* Check result */ 251 msg->result = cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_DATA, 1, &sum); 252 ret = cros_ec_check_result(ec, msg); 253 if (ret) 254 goto done; 255 256 /* Read back args */ 257 cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_ARGS, sizeof(args), (u8 *)&args); 258 259 if (args.data_size > msg->insize) { 260 dev_err(ec->dev, 261 "packet too long (%d bytes, expected %d)", 262 args.data_size, msg->insize); 263 ret = -ENOSPC; 264 goto done; 265 } 266 267 /* Start calculating response checksum */ 268 sum = msg->command + args.flags + args.command_version + args.data_size; 269 270 /* Read response and update checksum */ 271 sum += cros_ec_lpc_ops.read(EC_LPC_ADDR_HOST_PARAM, args.data_size, 272 msg->data); 273 274 /* Verify checksum */ 275 if (args.checksum != sum) { 276 dev_err(ec->dev, 277 "bad packet checksum, expected %02x, got %02x\n", 278 args.checksum, sum); 279 ret = -EBADMSG; 280 goto done; 281 } 282 283 /* Return actual amount of data received */ 284 ret = args.data_size; 285 done: 286 return ret; 287 } 288 289 /* Returns num bytes read, or negative on error. Doesn't need locking. */ 290 static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset, 291 unsigned int bytes, void *dest) 292 { 293 int i = offset; 294 char *s = dest; 295 int cnt = 0; 296 297 if (offset >= EC_MEMMAP_SIZE - bytes) 298 return -EINVAL; 299 300 /* fixed length */ 301 if (bytes) { 302 cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + offset, bytes, s); 303 return bytes; 304 } 305 306 /* string */ 307 for (; i < EC_MEMMAP_SIZE; i++, s++) { 308 cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + i, 1, s); 309 cnt++; 310 if (!*s) 311 break; 312 } 313 314 return cnt; 315 } 316 317 static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data) 318 { 319 static const char *env[] = { "ERROR=PANIC", NULL }; 320 struct cros_ec_device *ec_dev = data; 321 bool ec_has_more_events; 322 int ret; 323 324 ec_dev->last_event_time = cros_ec_get_time_ns(); 325 326 if (value == ACPI_NOTIFY_CROS_EC_PANIC) { 327 dev_emerg(ec_dev->dev, "CrOS EC Panic Reported. Shutdown is imminent!"); 328 blocking_notifier_call_chain(&ec_dev->panic_notifier, 0, ec_dev); 329 kobject_uevent_env(&ec_dev->dev->kobj, KOBJ_CHANGE, (char **)env); 330 /* Begin orderly shutdown. Force shutdown after 1 second. */ 331 hw_protection_shutdown("CrOS EC Panic", 1000); 332 /* Do not query for other events after a panic is reported */ 333 return; 334 } 335 336 if (ec_dev->mkbp_event_supported) 337 do { 338 ret = cros_ec_get_next_event(ec_dev, NULL, 339 &ec_has_more_events); 340 if (ret > 0) 341 blocking_notifier_call_chain( 342 &ec_dev->event_notifier, 0, 343 ec_dev); 344 } while (ec_has_more_events); 345 346 if (value == ACPI_NOTIFY_DEVICE_WAKE) 347 pm_system_wakeup(); 348 } 349 350 static int cros_ec_lpc_probe(struct platform_device *pdev) 351 { 352 struct device *dev = &pdev->dev; 353 struct acpi_device *adev; 354 acpi_status status; 355 struct cros_ec_device *ec_dev; 356 u8 buf[2] = {}; 357 int irq, ret; 358 359 /* 360 * The Framework Laptop (and possibly other non-ChromeOS devices) 361 * only exposes the eight I/O ports that are required for the Microchip EC. 362 * Requesting a larger reservation will fail. 363 */ 364 if (!devm_request_region(dev, EC_HOST_CMD_REGION0, 365 EC_HOST_CMD_MEC_REGION_SIZE, dev_name(dev))) { 366 dev_err(dev, "couldn't reserve MEC region\n"); 367 return -EBUSY; 368 } 369 370 cros_ec_lpc_mec_init(EC_HOST_CMD_REGION0, 371 EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE); 372 373 /* 374 * Read the mapped ID twice, the first one is assuming the 375 * EC is a Microchip Embedded Controller (MEC) variant, if the 376 * protocol fails, fallback to the non MEC variant and try to 377 * read again the ID. 378 */ 379 cros_ec_lpc_ops.read = cros_ec_lpc_mec_read_bytes; 380 cros_ec_lpc_ops.write = cros_ec_lpc_mec_write_bytes; 381 cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf); 382 if (buf[0] != 'E' || buf[1] != 'C') { 383 if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, 384 dev_name(dev))) { 385 dev_err(dev, "couldn't reserve memmap region\n"); 386 return -EBUSY; 387 } 388 389 /* Re-assign read/write operations for the non MEC variant */ 390 cros_ec_lpc_ops.read = cros_ec_lpc_read_bytes; 391 cros_ec_lpc_ops.write = cros_ec_lpc_write_bytes; 392 cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, 393 buf); 394 if (buf[0] != 'E' || buf[1] != 'C') { 395 dev_err(dev, "EC ID not detected\n"); 396 return -ENODEV; 397 } 398 399 /* Reserve the remaining I/O ports required by the non-MEC protocol. */ 400 if (!devm_request_region(dev, EC_HOST_CMD_REGION0 + EC_HOST_CMD_MEC_REGION_SIZE, 401 EC_HOST_CMD_REGION_SIZE - EC_HOST_CMD_MEC_REGION_SIZE, 402 dev_name(dev))) { 403 dev_err(dev, "couldn't reserve remainder of region0\n"); 404 return -EBUSY; 405 } 406 if (!devm_request_region(dev, EC_HOST_CMD_REGION1, 407 EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { 408 dev_err(dev, "couldn't reserve region1\n"); 409 return -EBUSY; 410 } 411 } 412 413 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); 414 if (!ec_dev) 415 return -ENOMEM; 416 417 platform_set_drvdata(pdev, ec_dev); 418 ec_dev->dev = dev; 419 ec_dev->phys_name = dev_name(dev); 420 ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc; 421 ec_dev->pkt_xfer = cros_ec_pkt_xfer_lpc; 422 ec_dev->cmd_readmem = cros_ec_lpc_readmem; 423 ec_dev->din_size = sizeof(struct ec_host_response) + 424 sizeof(struct ec_response_get_protocol_info); 425 ec_dev->dout_size = sizeof(struct ec_host_request); 426 427 /* 428 * Some boards do not have an IRQ allotted for cros_ec_lpc, 429 * which makes ENXIO an expected (and safe) scenario. 430 */ 431 irq = platform_get_irq_optional(pdev, 0); 432 if (irq > 0) 433 ec_dev->irq = irq; 434 else if (irq != -ENXIO) { 435 dev_err(dev, "couldn't retrieve IRQ number (%d)\n", irq); 436 return irq; 437 } 438 439 ret = cros_ec_register(ec_dev); 440 if (ret) { 441 dev_err(dev, "couldn't register ec_dev (%d)\n", ret); 442 return ret; 443 } 444 445 /* 446 * Connect a notify handler to process MKBP messages if we have a 447 * companion ACPI device. 448 */ 449 adev = ACPI_COMPANION(dev); 450 if (adev) { 451 status = acpi_install_notify_handler(adev->handle, 452 ACPI_ALL_NOTIFY, 453 cros_ec_lpc_acpi_notify, 454 ec_dev); 455 if (ACPI_FAILURE(status)) 456 dev_warn(dev, "Failed to register notifier %08x\n", 457 status); 458 } 459 460 return 0; 461 } 462 463 static int cros_ec_lpc_remove(struct platform_device *pdev) 464 { 465 struct cros_ec_device *ec_dev = platform_get_drvdata(pdev); 466 struct acpi_device *adev; 467 468 adev = ACPI_COMPANION(&pdev->dev); 469 if (adev) 470 acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY, 471 cros_ec_lpc_acpi_notify); 472 473 cros_ec_unregister(ec_dev); 474 475 return 0; 476 } 477 478 static const struct acpi_device_id cros_ec_lpc_acpi_device_ids[] = { 479 { ACPI_DRV_NAME, 0 }, 480 { } 481 }; 482 MODULE_DEVICE_TABLE(acpi, cros_ec_lpc_acpi_device_ids); 483 484 static const struct dmi_system_id cros_ec_lpc_dmi_table[] __initconst = { 485 { 486 /* 487 * Today all Chromebooks/boxes ship with Google_* as version and 488 * coreboot as bios vendor. No other systems with this 489 * combination are known to date. 490 */ 491 .matches = { 492 DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"), 493 DMI_MATCH(DMI_BIOS_VERSION, "Google_"), 494 }, 495 }, 496 { 497 /* 498 * If the box is running custom coreboot firmware then the 499 * DMI BIOS version string will not be matched by "Google_", 500 * but the system vendor string will still be matched by 501 * "GOOGLE". 502 */ 503 .matches = { 504 DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"), 505 DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), 506 }, 507 }, 508 { 509 /* x86-link, the Chromebook Pixel. */ 510 .matches = { 511 DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), 512 DMI_MATCH(DMI_PRODUCT_NAME, "Link"), 513 }, 514 }, 515 { 516 /* x86-samus, the Chromebook Pixel 2. */ 517 .matches = { 518 DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), 519 DMI_MATCH(DMI_PRODUCT_NAME, "Samus"), 520 }, 521 }, 522 { 523 /* x86-peppy, the Acer C720 Chromebook. */ 524 .matches = { 525 DMI_MATCH(DMI_SYS_VENDOR, "Acer"), 526 DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"), 527 }, 528 }, 529 { 530 /* x86-glimmer, the Lenovo Thinkpad Yoga 11e. */ 531 .matches = { 532 DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"), 533 DMI_MATCH(DMI_PRODUCT_NAME, "Glimmer"), 534 }, 535 }, 536 /* A small number of non-Chromebook/box machines also use the ChromeOS EC */ 537 { 538 /* the Framework Laptop */ 539 .matches = { 540 DMI_MATCH(DMI_SYS_VENDOR, "Framework"), 541 DMI_MATCH(DMI_PRODUCT_NAME, "Laptop"), 542 }, 543 }, 544 { /* sentinel */ } 545 }; 546 MODULE_DEVICE_TABLE(dmi, cros_ec_lpc_dmi_table); 547 548 #ifdef CONFIG_PM_SLEEP 549 static int cros_ec_lpc_prepare(struct device *dev) 550 { 551 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 552 553 return cros_ec_suspend(ec_dev); 554 } 555 556 static void cros_ec_lpc_complete(struct device *dev) 557 { 558 struct cros_ec_device *ec_dev = dev_get_drvdata(dev); 559 cros_ec_resume(ec_dev); 560 } 561 #endif 562 563 static const struct dev_pm_ops cros_ec_lpc_pm_ops = { 564 #ifdef CONFIG_PM_SLEEP 565 .prepare = cros_ec_lpc_prepare, 566 .complete = cros_ec_lpc_complete 567 #endif 568 }; 569 570 static struct platform_driver cros_ec_lpc_driver = { 571 .driver = { 572 .name = DRV_NAME, 573 .acpi_match_table = cros_ec_lpc_acpi_device_ids, 574 .pm = &cros_ec_lpc_pm_ops, 575 /* 576 * ACPI child devices may probe before us, and they racily 577 * check our drvdata pointer. Force synchronous probe until 578 * those races are resolved. 579 */ 580 .probe_type = PROBE_FORCE_SYNCHRONOUS, 581 }, 582 .probe = cros_ec_lpc_probe, 583 .remove = cros_ec_lpc_remove, 584 }; 585 586 static struct platform_device cros_ec_lpc_device = { 587 .name = DRV_NAME 588 }; 589 590 static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level, 591 void *context, void **retval) 592 { 593 *(bool *)context = true; 594 return AE_CTRL_TERMINATE; 595 } 596 597 static int __init cros_ec_lpc_init(void) 598 { 599 int ret; 600 acpi_status status; 601 602 status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device, 603 &cros_ec_lpc_acpi_device_found, NULL); 604 if (ACPI_FAILURE(status)) 605 pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME); 606 607 if (!cros_ec_lpc_acpi_device_found && 608 !dmi_check_system(cros_ec_lpc_dmi_table)) { 609 pr_err(DRV_NAME ": unsupported system.\n"); 610 return -ENODEV; 611 } 612 613 /* Register the driver */ 614 ret = platform_driver_register(&cros_ec_lpc_driver); 615 if (ret) { 616 pr_err(DRV_NAME ": can't register driver: %d\n", ret); 617 return ret; 618 } 619 620 if (!cros_ec_lpc_acpi_device_found) { 621 /* Register the device, and it'll get hooked up automatically */ 622 ret = platform_device_register(&cros_ec_lpc_device); 623 if (ret) { 624 pr_err(DRV_NAME ": can't register device: %d\n", ret); 625 platform_driver_unregister(&cros_ec_lpc_driver); 626 } 627 } 628 629 return ret; 630 } 631 632 static void __exit cros_ec_lpc_exit(void) 633 { 634 if (!cros_ec_lpc_acpi_device_found) 635 platform_device_unregister(&cros_ec_lpc_device); 636 platform_driver_unregister(&cros_ec_lpc_driver); 637 } 638 639 module_init(cros_ec_lpc_init); 640 module_exit(cros_ec_lpc_exit); 641 642 MODULE_LICENSE("GPL"); 643 MODULE_DESCRIPTION("ChromeOS EC LPC driver"); 644