1 /* 2 * Copyright (C) 2011 Infineon Technologies 3 * 4 * Authors: 5 * Peter Huewe <huewe.external@infineon.com> 6 * 7 * Description: 8 * Device driver for TCG/TCPA TPM (trusted platform module). 9 * Specifications at www.trustedcomputinggroup.org 10 * 11 * This device driver implements the TPM interface as defined in 12 * the TCG TPM Interface Spec version 1.2, revision 1.0 and the 13 * Infineon I2C Protocol Stack Specification v0.20. 14 * 15 * It is based on the Linux kernel driver tpm.c from Leendert van 16 * Dorn, Dave Safford, Reiner Sailer, and Kyleen Hall. 17 * 18 * Version: 2.1.1 19 * 20 * SPDX-License-Identifier: GPL-2.0 21 */ 22 23 #include <common.h> 24 #include <dm.h> 25 #include <fdtdec.h> 26 #include <i2c.h> 27 #include <tpm.h> 28 #include <linux/errno.h> 29 #include <linux/compiler.h> 30 #include <linux/types.h> 31 #include <linux/unaligned/be_byteshift.h> 32 33 #include "tpm_tis.h" 34 #include "tpm_internal.h" 35 36 enum i2c_chip_type { 37 SLB9635, 38 SLB9645, 39 UNKNOWN, 40 }; 41 42 /* expected value for DIDVID register */ 43 #define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L 44 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L 45 46 static const char * const chip_name[] = { 47 [SLB9635] = "slb9635tt", 48 [SLB9645] = "slb9645tt", 49 [UNKNOWN] = "unknown/fallback to slb9635", 50 }; 51 52 #define TPM_ACCESS(l) (0x0000 | ((l) << 4)) 53 #define TPM_STS(l) (0x0001 | ((l) << 4)) 54 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4)) 55 #define TPM_DID_VID(l) (0x0006 | ((l) << 4)) 56 57 /* 58 * tpm_tis_i2c_read() - read from TPM register 59 * @addr: register address to read from 60 * @buffer: provided by caller 61 * @len: number of bytes to read 62 * 63 * Read len bytes from TPM register and put them into 64 * buffer (little-endian format, i.e. first byte is put into buffer[0]). 65 * 66 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 67 * values have to be swapped. 68 * 69 * Return -EIO on error, 0 on success. 70 */ 71 static int tpm_tis_i2c_read(struct udevice *dev, u8 addr, u8 *buffer, 72 size_t len) 73 { 74 struct tpm_chip *chip = dev_get_priv(dev); 75 int rc; 76 int count; 77 uint32_t addrbuf = addr; 78 79 if ((chip->chip_type == SLB9635) || (chip->chip_type == UNKNOWN)) { 80 /* slb9635 protocol should work in both cases */ 81 for (count = 0; count < MAX_COUNT; count++) { 82 rc = dm_i2c_write(dev, 0, (uchar *)&addrbuf, 1); 83 if (rc == 0) 84 break; /* Success, break to skip sleep */ 85 udelay(SLEEP_DURATION_US); 86 } 87 if (rc) 88 return rc; 89 90 /* After the TPM has successfully received the register address 91 * it needs some time, thus we're sleeping here again, before 92 * retrieving the data 93 */ 94 for (count = 0; count < MAX_COUNT; count++) { 95 udelay(SLEEP_DURATION_US); 96 rc = dm_i2c_read(dev, 0, buffer, len); 97 if (rc == 0) 98 break; /* success, break to skip sleep */ 99 } 100 } else { 101 /* 102 * Use a combined read for newer chips. 103 * Unfortunately the smbus functions are not suitable due to 104 * the 32 byte limit of the smbus. 105 * Retries should usually not be needed, but are kept just to 106 * be safe on the safe side. 107 */ 108 for (count = 0; count < MAX_COUNT; count++) { 109 rc = dm_i2c_read(dev, addr, buffer, len); 110 if (rc == 0) 111 break; /* break here to skip sleep */ 112 udelay(SLEEP_DURATION_US); 113 } 114 } 115 116 /* Take care of 'guard time' */ 117 udelay(SLEEP_DURATION_US); 118 if (rc) 119 return rc; 120 121 return 0; 122 } 123 124 static int tpm_tis_i2c_write_generic(struct udevice *dev, u8 addr, 125 const u8 *buffer, size_t len, 126 unsigned int sleep_time_us, u8 max_count) 127 { 128 struct tpm_chip_priv *priv = dev_get_uclass_priv(dev); 129 struct tpm_chip *chip = dev_get_priv(dev); 130 int rc = 0; 131 int count; 132 133 if (chip->chip_type == SLB9635) { 134 /* Prepare send buffer to include the address */ 135 priv->buf[0] = addr; 136 memcpy(&(priv->buf[1]), buffer, len); 137 buffer = priv->buf; 138 len++; 139 addr = 0; 140 } 141 142 for (count = 0; count < max_count; count++) { 143 rc = dm_i2c_write(dev, addr, buffer, len); 144 if (rc == 0) 145 break; /* Success, break to skip sleep */ 146 udelay(sleep_time_us); 147 } 148 149 /* take care of 'guard time' */ 150 udelay(sleep_time_us); 151 if (rc) 152 return rc; 153 154 return 0; 155 } 156 157 /* 158 * tpm_tis_i2c_write() - write to TPM register 159 * @addr: register address to write to 160 * @buffer: containing data to be written 161 * @len: number of bytes to write 162 * 163 * Write len bytes from provided buffer to TPM register (little 164 * endian format, i.e. buffer[0] is written as first byte). 165 * 166 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 167 * values have to be swapped. 168 * 169 * NOTE: use this function instead of the tpm_tis_i2c_write_generic function. 170 * 171 * Return -EIO on error, 0 on success 172 */ 173 static int tpm_tis_i2c_write(struct udevice *dev, u8 addr, const u8 *buffer, 174 size_t len) 175 { 176 return tpm_tis_i2c_write_generic(dev, addr, buffer, len, 177 SLEEP_DURATION_US, MAX_COUNT); 178 } 179 180 /* 181 * This function is needed especially for the cleanup situation after 182 * sending TPM_READY 183 */ 184 static int tpm_tis_i2c_write_long(struct udevice *dev, u8 addr, u8 *buffer, 185 size_t len) 186 { 187 return tpm_tis_i2c_write_generic(dev, addr, buffer, len, 188 SLEEP_DURATION_LONG_US, 189 MAX_COUNT_LONG); 190 } 191 192 static int tpm_tis_i2c_check_locality(struct udevice *dev, int loc) 193 { 194 const u8 mask = TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID; 195 struct tpm_chip *chip = dev_get_priv(dev); 196 u8 buf; 197 int rc; 198 199 rc = tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1); 200 if (rc < 0) 201 return rc; 202 203 if ((buf & mask) == mask) { 204 chip->locality = loc; 205 return loc; 206 } 207 208 return -ENOENT; 209 } 210 211 static void tpm_tis_i2c_release_locality(struct udevice *dev, int loc, 212 int force) 213 { 214 const u8 mask = TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID; 215 u8 buf; 216 217 if (tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1) < 0) 218 return; 219 220 if (force || (buf & mask) == mask) { 221 buf = TPM_ACCESS_ACTIVE_LOCALITY; 222 tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1); 223 } 224 } 225 226 static int tpm_tis_i2c_request_locality(struct udevice *dev, int loc) 227 { 228 struct tpm_chip *chip = dev_get_priv(dev); 229 unsigned long start, stop; 230 u8 buf = TPM_ACCESS_REQUEST_USE; 231 int rc; 232 233 rc = tpm_tis_i2c_check_locality(dev, loc); 234 if (rc >= 0) { 235 debug("%s: Already have locality\n", __func__); 236 return loc; /* We already have the locality */ 237 } else if (rc != -ENOENT) { 238 debug("%s: Failed to get locality: %d\n", __func__, rc); 239 return rc; 240 } 241 242 rc = tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1); 243 if (rc) { 244 debug("%s: Failed to write to TPM: %d\n", __func__, rc); 245 return rc; 246 } 247 248 /* Wait for burstcount */ 249 start = get_timer(0); 250 stop = chip->timeout_a; 251 do { 252 rc = tpm_tis_i2c_check_locality(dev, loc); 253 if (rc >= 0) { 254 debug("%s: Have locality\n", __func__); 255 return loc; 256 } else if (rc != -ENOENT) { 257 debug("%s: Failed to get locality: %d\n", __func__, rc); 258 return rc; 259 } 260 mdelay(TPM_TIMEOUT_MS); 261 } while (get_timer(start) < stop); 262 debug("%s: Timeout getting locality: %d\n", __func__, rc); 263 264 return rc; 265 } 266 267 static u8 tpm_tis_i2c_status(struct udevice *dev) 268 { 269 struct tpm_chip *chip = dev_get_priv(dev); 270 /* NOTE: Since i2c read may fail, return 0 in this case --> time-out */ 271 u8 buf; 272 273 if (tpm_tis_i2c_read(dev, TPM_STS(chip->locality), &buf, 1) < 0) 274 return 0; 275 else 276 return buf; 277 } 278 279 static int tpm_tis_i2c_ready(struct udevice *dev) 280 { 281 struct tpm_chip *chip = dev_get_priv(dev); 282 int rc; 283 284 /* This causes the current command to be aborted */ 285 u8 buf = TPM_STS_COMMAND_READY; 286 287 debug("%s\n", __func__); 288 rc = tpm_tis_i2c_write_long(dev, TPM_STS(chip->locality), &buf, 1); 289 if (rc) 290 debug("%s: rc=%d\n", __func__, rc); 291 292 return rc; 293 } 294 295 static ssize_t tpm_tis_i2c_get_burstcount(struct udevice *dev) 296 { 297 struct tpm_chip *chip = dev_get_priv(dev); 298 unsigned long start, stop; 299 ssize_t burstcnt; 300 u8 addr, buf[3]; 301 302 /* Wait for burstcount */ 303 /* XXX: Which timeout value? Spec has 2 answers (c & d) */ 304 start = get_timer(0); 305 stop = chip->timeout_d; 306 do { 307 /* Note: STS is little endian */ 308 addr = TPM_STS(chip->locality) + 1; 309 if (tpm_tis_i2c_read(dev, addr, buf, 3) < 0) 310 burstcnt = 0; 311 else 312 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0]; 313 314 if (burstcnt) 315 return burstcnt; 316 mdelay(TPM_TIMEOUT_MS); 317 } while (get_timer(start) < stop); 318 319 return -EBUSY; 320 } 321 322 static int tpm_tis_i2c_wait_for_stat(struct udevice *dev, u8 mask, 323 unsigned long timeout, int *status) 324 { 325 unsigned long start, stop; 326 327 /* Check current status */ 328 *status = tpm_tis_i2c_status(dev); 329 if ((*status & mask) == mask) 330 return 0; 331 332 start = get_timer(0); 333 stop = timeout; 334 do { 335 mdelay(TPM_TIMEOUT_MS); 336 *status = tpm_tis_i2c_status(dev); 337 if ((*status & mask) == mask) 338 return 0; 339 } while (get_timer(start) < stop); 340 341 return -ETIMEDOUT; 342 } 343 344 static int tpm_tis_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count) 345 { 346 struct tpm_chip *chip = dev_get_priv(dev); 347 size_t size = 0; 348 ssize_t burstcnt; 349 int rc; 350 351 while (size < count) { 352 burstcnt = tpm_tis_i2c_get_burstcount(dev); 353 354 /* burstcount < 0 -> tpm is busy */ 355 if (burstcnt < 0) 356 return burstcnt; 357 358 /* Limit received data to max left */ 359 if (burstcnt > (count - size)) 360 burstcnt = count - size; 361 362 rc = tpm_tis_i2c_read(dev, TPM_DATA_FIFO(chip->locality), 363 &(buf[size]), burstcnt); 364 if (rc == 0) 365 size += burstcnt; 366 } 367 368 return size; 369 } 370 371 static int tpm_tis_i2c_recv(struct udevice *dev, u8 *buf, size_t count) 372 { 373 struct tpm_chip *chip = dev_get_priv(dev); 374 int size = 0; 375 int status; 376 unsigned int expected; 377 int rc; 378 379 status = tpm_tis_i2c_status(dev); 380 if (status == TPM_STS_COMMAND_READY) 381 return -EINTR; 382 if ((status & (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) != 383 (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) 384 return -EAGAIN; 385 386 debug("...got it;\n"); 387 388 /* Read first 10 bytes, including tag, paramsize, and result */ 389 size = tpm_tis_i2c_recv_data(dev, buf, TPM_HEADER_SIZE); 390 if (size < TPM_HEADER_SIZE) { 391 debug("Unable to read header\n"); 392 return size < 0 ? size : -EIO; 393 } 394 395 expected = get_unaligned_be32(buf + TPM_RSP_SIZE_BYTE); 396 if ((size_t)expected > count || (size_t)expected < TPM_HEADER_SIZE) { 397 debug("Error size=%x, expected=%x, count=%x\n", size, expected, 398 count); 399 return -ENOSPC; 400 } 401 402 size += tpm_tis_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE], 403 expected - TPM_HEADER_SIZE); 404 if (size < expected) { 405 debug("Unable to read remainder of result\n"); 406 return -ETIMEDOUT; 407 } 408 409 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, chip->timeout_c, 410 &status); 411 if (rc) 412 return rc; 413 if (status & TPM_STS_DATA_AVAIL) { /* Retry? */ 414 debug("Error left over data\n"); 415 return -EIO; 416 } 417 418 return size; 419 } 420 421 static int tpm_tis_i2c_send(struct udevice *dev, const u8 *buf, size_t len) 422 { 423 struct tpm_chip *chip = dev_get_priv(dev); 424 int rc, status; 425 size_t burstcnt; 426 size_t count = 0; 427 int retry = 0; 428 u8 sts = TPM_STS_GO; 429 430 debug("%s: len=%d\n", __func__, len); 431 if (len > TPM_DEV_BUFSIZE) 432 return -E2BIG; /* Command is too long for our tpm, sorry */ 433 434 if (tpm_tis_i2c_request_locality(dev, 0) < 0) 435 return -EBUSY; 436 437 status = tpm_tis_i2c_status(dev); 438 if ((status & TPM_STS_COMMAND_READY) == 0) { 439 rc = tpm_tis_i2c_ready(dev); 440 if (rc) 441 return rc; 442 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY, 443 chip->timeout_b, &status); 444 if (rc) 445 return rc; 446 } 447 448 burstcnt = tpm_tis_i2c_get_burstcount(dev); 449 450 /* burstcount < 0 -> tpm is busy */ 451 if (burstcnt < 0) 452 return burstcnt; 453 454 while (count < len) { 455 udelay(300); 456 if (burstcnt > len - count) 457 burstcnt = len - count; 458 459 #ifdef CONFIG_TPM_TIS_I2C_BURST_LIMITATION 460 if (retry && burstcnt > CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN) 461 burstcnt = CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN; 462 #endif /* CONFIG_TPM_TIS_I2C_BURST_LIMITATION */ 463 464 rc = tpm_tis_i2c_write(dev, TPM_DATA_FIFO(chip->locality), 465 &(buf[count]), burstcnt); 466 if (rc == 0) 467 count += burstcnt; 468 else { 469 debug("%s: error\n", __func__); 470 if (retry++ > 10) 471 return -EIO; 472 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, 473 chip->timeout_c, 474 &status); 475 if (rc) 476 return rc; 477 478 if ((status & TPM_STS_DATA_EXPECT) == 0) 479 return -EIO; 480 } 481 } 482 483 /* Go and do it */ 484 rc = tpm_tis_i2c_write(dev, TPM_STS(chip->locality), &sts, 1); 485 if (rc < 0) 486 return rc; 487 debug("%s: done, rc=%d\n", __func__, rc); 488 489 return len; 490 } 491 492 static int tpm_tis_i2c_cleanup(struct udevice *dev) 493 { 494 struct tpm_chip *chip = dev_get_priv(dev); 495 496 tpm_tis_i2c_ready(dev); 497 /* 498 * The TPM needs some time to clean up here, 499 * so we sleep rather than keeping the bus busy 500 */ 501 mdelay(2); 502 tpm_tis_i2c_release_locality(dev, chip->locality, 0); 503 504 return 0; 505 } 506 507 static int tpm_tis_i2c_init(struct udevice *dev) 508 { 509 struct tpm_chip *chip = dev_get_priv(dev); 510 u32 vendor; 511 u32 expected_did_vid; 512 int rc; 513 514 chip->is_open = 1; 515 516 /* Default timeouts - these could move to the device tree */ 517 chip->timeout_a = TIS_SHORT_TIMEOUT_MS; 518 chip->timeout_b = TIS_LONG_TIMEOUT_MS; 519 chip->timeout_c = TIS_SHORT_TIMEOUT_MS; 520 chip->timeout_d = TIS_SHORT_TIMEOUT_MS; 521 522 rc = tpm_tis_i2c_request_locality(dev, 0); 523 if (rc < 0) 524 return rc; 525 526 /* Read four bytes from DID_VID register */ 527 if (tpm_tis_i2c_read(dev, TPM_DID_VID(0), (uchar *)&vendor, 4) < 0) { 528 tpm_tis_i2c_release_locality(dev, 0, 1); 529 return -EIO; 530 } 531 532 if (chip->chip_type == SLB9635) { 533 vendor = be32_to_cpu(vendor); 534 expected_did_vid = TPM_TIS_I2C_DID_VID_9635; 535 } else { 536 /* device id and byte order has changed for newer i2c tpms */ 537 expected_did_vid = TPM_TIS_I2C_DID_VID_9645; 538 } 539 540 if (chip->chip_type != UNKNOWN && vendor != expected_did_vid) { 541 pr_err("Vendor id did not match! ID was %08x\n", vendor); 542 return -ENODEV; 543 } 544 545 chip->vend_dev = vendor; 546 debug("1.2 TPM (chip type %s device-id 0x%X)\n", 547 chip_name[chip->chip_type], vendor >> 16); 548 549 /* 550 * A timeout query to TPM can be placed here. 551 * Standard timeout values are used so far 552 */ 553 554 return 0; 555 } 556 557 static int tpm_tis_i2c_open(struct udevice *dev) 558 { 559 struct tpm_chip *chip = dev_get_priv(dev); 560 int rc; 561 562 debug("%s: start\n", __func__); 563 if (chip->is_open) 564 return -EBUSY; 565 rc = tpm_tis_i2c_init(dev); 566 if (rc < 0) 567 chip->is_open = 0; 568 569 return rc; 570 } 571 572 static int tpm_tis_i2c_close(struct udevice *dev) 573 { 574 struct tpm_chip *chip = dev_get_priv(dev); 575 576 if (chip->is_open) { 577 tpm_tis_i2c_release_locality(dev, chip->locality, 1); 578 chip->is_open = 0; 579 chip->vend_dev = 0; 580 } 581 582 return 0; 583 } 584 585 static int tpm_tis_get_desc(struct udevice *dev, char *buf, int size) 586 { 587 struct tpm_chip *chip = dev_get_priv(dev); 588 589 if (size < 50) 590 return -ENOSPC; 591 592 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)", 593 chip->is_open ? "open" : "closed", 594 chip_name[chip->chip_type], 595 chip->vend_dev >> 16); 596 } 597 598 static int tpm_tis_i2c_probe(struct udevice *dev) 599 { 600 struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev); 601 struct tpm_chip *chip = dev_get_priv(dev); 602 603 chip->chip_type = dev_get_driver_data(dev); 604 605 /* TODO: These need to be checked and tuned */ 606 uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS; 607 uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS; 608 uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS; 609 uc_priv->retry_time_ms = TPM_TIMEOUT_MS; 610 611 return 0; 612 } 613 614 static const struct tpm_ops tpm_tis_i2c_ops = { 615 .open = tpm_tis_i2c_open, 616 .close = tpm_tis_i2c_close, 617 .get_desc = tpm_tis_get_desc, 618 .send = tpm_tis_i2c_send, 619 .recv = tpm_tis_i2c_recv, 620 .cleanup = tpm_tis_i2c_cleanup, 621 }; 622 623 static const struct udevice_id tpm_tis_i2c_ids[] = { 624 { .compatible = "infineon,slb9635tt", .data = SLB9635 }, 625 { .compatible = "infineon,slb9645tt", .data = SLB9645 }, 626 { } 627 }; 628 629 U_BOOT_DRIVER(tpm_tis_i2c) = { 630 .name = "tpm_tis_infineon", 631 .id = UCLASS_TPM, 632 .of_match = tpm_tis_i2c_ids, 633 .ops = &tpm_tis_i2c_ops, 634 .probe = tpm_tis_i2c_probe, 635 .priv_auto_alloc_size = sizeof(struct tpm_chip), 636 }; 637