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 DECLARE_GLOBAL_DATA_PTR; 37 38 enum i2c_chip_type { 39 SLB9635, 40 SLB9645, 41 UNKNOWN, 42 }; 43 44 /* expected value for DIDVID register */ 45 #define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L 46 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L 47 48 static const char * const chip_name[] = { 49 [SLB9635] = "slb9635tt", 50 [SLB9645] = "slb9645tt", 51 [UNKNOWN] = "unknown/fallback to slb9635", 52 }; 53 54 #define TPM_ACCESS(l) (0x0000 | ((l) << 4)) 55 #define TPM_STS(l) (0x0001 | ((l) << 4)) 56 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4)) 57 #define TPM_DID_VID(l) (0x0006 | ((l) << 4)) 58 59 /* 60 * tpm_tis_i2c_read() - read from TPM register 61 * @addr: register address to read from 62 * @buffer: provided by caller 63 * @len: number of bytes to read 64 * 65 * Read len bytes from TPM register and put them into 66 * buffer (little-endian format, i.e. first byte is put into buffer[0]). 67 * 68 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 69 * values have to be swapped. 70 * 71 * Return -EIO on error, 0 on success. 72 */ 73 static int tpm_tis_i2c_read(struct udevice *dev, u8 addr, u8 *buffer, 74 size_t len) 75 { 76 struct tpm_chip *chip = dev_get_priv(dev); 77 int rc; 78 int count; 79 uint32_t addrbuf = addr; 80 81 if ((chip->chip_type == SLB9635) || (chip->chip_type == UNKNOWN)) { 82 /* slb9635 protocol should work in both cases */ 83 for (count = 0; count < MAX_COUNT; count++) { 84 rc = dm_i2c_write(dev, 0, (uchar *)&addrbuf, 1); 85 if (rc == 0) 86 break; /* Success, break to skip sleep */ 87 udelay(SLEEP_DURATION_US); 88 } 89 if (rc) 90 return rc; 91 92 /* After the TPM has successfully received the register address 93 * it needs some time, thus we're sleeping here again, before 94 * retrieving the data 95 */ 96 for (count = 0; count < MAX_COUNT; count++) { 97 udelay(SLEEP_DURATION_US); 98 rc = dm_i2c_read(dev, 0, buffer, len); 99 if (rc == 0) 100 break; /* success, break to skip sleep */ 101 } 102 } else { 103 /* 104 * Use a combined read for newer chips. 105 * Unfortunately the smbus functions are not suitable due to 106 * the 32 byte limit of the smbus. 107 * Retries should usually not be needed, but are kept just to 108 * be safe on the safe side. 109 */ 110 for (count = 0; count < MAX_COUNT; count++) { 111 rc = dm_i2c_read(dev, addr, buffer, len); 112 if (rc == 0) 113 break; /* break here to skip sleep */ 114 udelay(SLEEP_DURATION_US); 115 } 116 } 117 118 /* Take care of 'guard time' */ 119 udelay(SLEEP_DURATION_US); 120 if (rc) 121 return rc; 122 123 return 0; 124 } 125 126 static int tpm_tis_i2c_write_generic(struct udevice *dev, u8 addr, 127 const u8 *buffer, size_t len, 128 unsigned int sleep_time_us, u8 max_count) 129 { 130 struct tpm_chip_priv *priv = dev_get_uclass_priv(dev); 131 struct tpm_chip *chip = dev_get_priv(dev); 132 int rc = 0; 133 int count; 134 135 if (chip->chip_type == SLB9635) { 136 /* Prepare send buffer to include the address */ 137 priv->buf[0] = addr; 138 memcpy(&(priv->buf[1]), buffer, len); 139 buffer = priv->buf; 140 len++; 141 addr = 0; 142 } 143 144 for (count = 0; count < max_count; count++) { 145 rc = dm_i2c_write(dev, addr, buffer, len); 146 if (rc == 0) 147 break; /* Success, break to skip sleep */ 148 udelay(sleep_time_us); 149 } 150 151 /* take care of 'guard time' */ 152 udelay(sleep_time_us); 153 if (rc) 154 return rc; 155 156 return 0; 157 } 158 159 /* 160 * tpm_tis_i2c_write() - write to TPM register 161 * @addr: register address to write to 162 * @buffer: containing data to be written 163 * @len: number of bytes to write 164 * 165 * Write len bytes from provided buffer to TPM register (little 166 * endian format, i.e. buffer[0] is written as first byte). 167 * 168 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 169 * values have to be swapped. 170 * 171 * NOTE: use this function instead of the tpm_tis_i2c_write_generic function. 172 * 173 * Return -EIO on error, 0 on success 174 */ 175 static int tpm_tis_i2c_write(struct udevice *dev, u8 addr, const u8 *buffer, 176 size_t len) 177 { 178 return tpm_tis_i2c_write_generic(dev, addr, buffer, len, 179 SLEEP_DURATION_US, MAX_COUNT); 180 } 181 182 /* 183 * This function is needed especially for the cleanup situation after 184 * sending TPM_READY 185 */ 186 static int tpm_tis_i2c_write_long(struct udevice *dev, u8 addr, u8 *buffer, 187 size_t len) 188 { 189 return tpm_tis_i2c_write_generic(dev, addr, buffer, len, 190 SLEEP_DURATION_LONG_US, 191 MAX_COUNT_LONG); 192 } 193 194 static int tpm_tis_i2c_check_locality(struct udevice *dev, int loc) 195 { 196 const u8 mask = TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID; 197 struct tpm_chip *chip = dev_get_priv(dev); 198 u8 buf; 199 int rc; 200 201 rc = tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1); 202 if (rc < 0) 203 return rc; 204 205 if ((buf & mask) == mask) { 206 chip->locality = loc; 207 return loc; 208 } 209 210 return -ENOENT; 211 } 212 213 static void tpm_tis_i2c_release_locality(struct udevice *dev, int loc, 214 int force) 215 { 216 const u8 mask = TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID; 217 u8 buf; 218 219 if (tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1) < 0) 220 return; 221 222 if (force || (buf & mask) == mask) { 223 buf = TPM_ACCESS_ACTIVE_LOCALITY; 224 tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1); 225 } 226 } 227 228 static int tpm_tis_i2c_request_locality(struct udevice *dev, int loc) 229 { 230 struct tpm_chip *chip = dev_get_priv(dev); 231 unsigned long start, stop; 232 u8 buf = TPM_ACCESS_REQUEST_USE; 233 int rc; 234 235 rc = tpm_tis_i2c_check_locality(dev, loc); 236 if (rc >= 0) { 237 debug("%s: Already have locality\n", __func__); 238 return loc; /* We already have the locality */ 239 } else if (rc != -ENOENT) { 240 debug("%s: Failed to get locality: %d\n", __func__, rc); 241 return rc; 242 } 243 244 rc = tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1); 245 if (rc) { 246 debug("%s: Failed to write to TPM: %d\n", __func__, rc); 247 return rc; 248 } 249 250 /* Wait for burstcount */ 251 start = get_timer(0); 252 stop = chip->timeout_a; 253 do { 254 rc = tpm_tis_i2c_check_locality(dev, loc); 255 if (rc >= 0) { 256 debug("%s: Have locality\n", __func__); 257 return loc; 258 } else if (rc != -ENOENT) { 259 debug("%s: Failed to get locality: %d\n", __func__, rc); 260 return rc; 261 } 262 mdelay(TPM_TIMEOUT_MS); 263 } while (get_timer(start) < stop); 264 debug("%s: Timeout getting locality: %d\n", __func__, rc); 265 266 return rc; 267 } 268 269 static u8 tpm_tis_i2c_status(struct udevice *dev) 270 { 271 struct tpm_chip *chip = dev_get_priv(dev); 272 /* NOTE: Since i2c read may fail, return 0 in this case --> time-out */ 273 u8 buf; 274 275 if (tpm_tis_i2c_read(dev, TPM_STS(chip->locality), &buf, 1) < 0) 276 return 0; 277 else 278 return buf; 279 } 280 281 static int tpm_tis_i2c_ready(struct udevice *dev) 282 { 283 struct tpm_chip *chip = dev_get_priv(dev); 284 int rc; 285 286 /* This causes the current command to be aborted */ 287 u8 buf = TPM_STS_COMMAND_READY; 288 289 debug("%s\n", __func__); 290 rc = tpm_tis_i2c_write_long(dev, TPM_STS(chip->locality), &buf, 1); 291 if (rc) 292 debug("%s: rc=%d\n", __func__, rc); 293 294 return rc; 295 } 296 297 static ssize_t tpm_tis_i2c_get_burstcount(struct udevice *dev) 298 { 299 struct tpm_chip *chip = dev_get_priv(dev); 300 unsigned long start, stop; 301 ssize_t burstcnt; 302 u8 addr, buf[3]; 303 304 /* Wait for burstcount */ 305 /* XXX: Which timeout value? Spec has 2 answers (c & d) */ 306 start = get_timer(0); 307 stop = chip->timeout_d; 308 do { 309 /* Note: STS is little endian */ 310 addr = TPM_STS(chip->locality) + 1; 311 if (tpm_tis_i2c_read(dev, addr, buf, 3) < 0) 312 burstcnt = 0; 313 else 314 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0]; 315 316 if (burstcnt) 317 return burstcnt; 318 mdelay(TPM_TIMEOUT_MS); 319 } while (get_timer(start) < stop); 320 321 return -EBUSY; 322 } 323 324 static int tpm_tis_i2c_wait_for_stat(struct udevice *dev, u8 mask, 325 unsigned long timeout, int *status) 326 { 327 unsigned long start, stop; 328 329 /* Check current status */ 330 *status = tpm_tis_i2c_status(dev); 331 if ((*status & mask) == mask) 332 return 0; 333 334 start = get_timer(0); 335 stop = timeout; 336 do { 337 mdelay(TPM_TIMEOUT_MS); 338 *status = tpm_tis_i2c_status(dev); 339 if ((*status & mask) == mask) 340 return 0; 341 } while (get_timer(start) < stop); 342 343 return -ETIMEDOUT; 344 } 345 346 static int tpm_tis_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count) 347 { 348 struct tpm_chip *chip = dev_get_priv(dev); 349 size_t size = 0; 350 ssize_t burstcnt; 351 int rc; 352 353 while (size < count) { 354 burstcnt = tpm_tis_i2c_get_burstcount(dev); 355 356 /* burstcount < 0 -> tpm is busy */ 357 if (burstcnt < 0) 358 return burstcnt; 359 360 /* Limit received data to max left */ 361 if (burstcnt > (count - size)) 362 burstcnt = count - size; 363 364 rc = tpm_tis_i2c_read(dev, TPM_DATA_FIFO(chip->locality), 365 &(buf[size]), burstcnt); 366 if (rc == 0) 367 size += burstcnt; 368 } 369 370 return size; 371 } 372 373 static int tpm_tis_i2c_recv(struct udevice *dev, u8 *buf, size_t count) 374 { 375 struct tpm_chip *chip = dev_get_priv(dev); 376 int size = 0; 377 int status; 378 unsigned int expected; 379 int rc; 380 381 status = tpm_tis_i2c_status(dev); 382 if (status == TPM_STS_COMMAND_READY) 383 return -EINTR; 384 if ((status & (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) != 385 (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) 386 return -EAGAIN; 387 388 debug("...got it;\n"); 389 390 /* Read first 10 bytes, including tag, paramsize, and result */ 391 size = tpm_tis_i2c_recv_data(dev, buf, TPM_HEADER_SIZE); 392 if (size < TPM_HEADER_SIZE) { 393 debug("Unable to read header\n"); 394 return size < 0 ? size : -EIO; 395 } 396 397 expected = get_unaligned_be32(buf + TPM_RSP_SIZE_BYTE); 398 if ((size_t)expected > count || (size_t)expected < TPM_HEADER_SIZE) { 399 debug("Error size=%x, expected=%x, count=%x\n", size, expected, 400 count); 401 return -ENOSPC; 402 } 403 404 size += tpm_tis_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE], 405 expected - TPM_HEADER_SIZE); 406 if (size < expected) { 407 debug("Unable to read remainder of result\n"); 408 return -ETIMEDOUT; 409 } 410 411 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, chip->timeout_c, 412 &status); 413 if (rc) 414 return rc; 415 if (status & TPM_STS_DATA_AVAIL) { /* Retry? */ 416 debug("Error left over data\n"); 417 return -EIO; 418 } 419 420 return size; 421 } 422 423 static int tpm_tis_i2c_send(struct udevice *dev, const u8 *buf, size_t len) 424 { 425 struct tpm_chip *chip = dev_get_priv(dev); 426 int rc, status; 427 size_t burstcnt; 428 size_t count = 0; 429 int retry = 0; 430 u8 sts = TPM_STS_GO; 431 432 debug("%s: len=%d\n", __func__, len); 433 if (len > TPM_DEV_BUFSIZE) 434 return -E2BIG; /* Command is too long for our tpm, sorry */ 435 436 if (tpm_tis_i2c_request_locality(dev, 0) < 0) 437 return -EBUSY; 438 439 status = tpm_tis_i2c_status(dev); 440 if ((status & TPM_STS_COMMAND_READY) == 0) { 441 rc = tpm_tis_i2c_ready(dev); 442 if (rc) 443 return rc; 444 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY, 445 chip->timeout_b, &status); 446 if (rc) 447 return rc; 448 } 449 450 burstcnt = tpm_tis_i2c_get_burstcount(dev); 451 452 /* burstcount < 0 -> tpm is busy */ 453 if (burstcnt < 0) 454 return burstcnt; 455 456 while (count < len) { 457 udelay(300); 458 if (burstcnt > len - count) 459 burstcnt = len - count; 460 461 #ifdef CONFIG_TPM_TIS_I2C_BURST_LIMITATION 462 if (retry && burstcnt > CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN) 463 burstcnt = CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN; 464 #endif /* CONFIG_TPM_TIS_I2C_BURST_LIMITATION */ 465 466 rc = tpm_tis_i2c_write(dev, TPM_DATA_FIFO(chip->locality), 467 &(buf[count]), burstcnt); 468 if (rc == 0) 469 count += burstcnt; 470 else { 471 debug("%s: error\n", __func__); 472 if (retry++ > 10) 473 return -EIO; 474 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, 475 chip->timeout_c, 476 &status); 477 if (rc) 478 return rc; 479 480 if ((status & TPM_STS_DATA_EXPECT) == 0) 481 return -EIO; 482 } 483 } 484 485 /* Go and do it */ 486 rc = tpm_tis_i2c_write(dev, TPM_STS(chip->locality), &sts, 1); 487 if (rc < 0) 488 return rc; 489 debug("%s: done, rc=%d\n", __func__, rc); 490 491 return len; 492 } 493 494 static int tpm_tis_i2c_cleanup(struct udevice *dev) 495 { 496 struct tpm_chip *chip = dev_get_priv(dev); 497 498 tpm_tis_i2c_ready(dev); 499 /* 500 * The TPM needs some time to clean up here, 501 * so we sleep rather than keeping the bus busy 502 */ 503 mdelay(2); 504 tpm_tis_i2c_release_locality(dev, chip->locality, 0); 505 506 return 0; 507 } 508 509 static int tpm_tis_i2c_init(struct udevice *dev) 510 { 511 struct tpm_chip *chip = dev_get_priv(dev); 512 u32 vendor; 513 u32 expected_did_vid; 514 int rc; 515 516 chip->is_open = 1; 517 518 /* Default timeouts - these could move to the device tree */ 519 chip->timeout_a = TIS_SHORT_TIMEOUT_MS; 520 chip->timeout_b = TIS_LONG_TIMEOUT_MS; 521 chip->timeout_c = TIS_SHORT_TIMEOUT_MS; 522 chip->timeout_d = TIS_SHORT_TIMEOUT_MS; 523 524 rc = tpm_tis_i2c_request_locality(dev, 0); 525 if (rc < 0) 526 return rc; 527 528 /* Read four bytes from DID_VID register */ 529 if (tpm_tis_i2c_read(dev, TPM_DID_VID(0), (uchar *)&vendor, 4) < 0) { 530 tpm_tis_i2c_release_locality(dev, 0, 1); 531 return -EIO; 532 } 533 534 if (chip->chip_type == SLB9635) { 535 vendor = be32_to_cpu(vendor); 536 expected_did_vid = TPM_TIS_I2C_DID_VID_9635; 537 } else { 538 /* device id and byte order has changed for newer i2c tpms */ 539 expected_did_vid = TPM_TIS_I2C_DID_VID_9645; 540 } 541 542 if (chip->chip_type != UNKNOWN && vendor != expected_did_vid) { 543 pr_err("Vendor id did not match! ID was %08x\n", vendor); 544 return -ENODEV; 545 } 546 547 chip->vend_dev = vendor; 548 debug("1.2 TPM (chip type %s device-id 0x%X)\n", 549 chip_name[chip->chip_type], vendor >> 16); 550 551 /* 552 * A timeout query to TPM can be placed here. 553 * Standard timeout values are used so far 554 */ 555 556 return 0; 557 } 558 559 static int tpm_tis_i2c_open(struct udevice *dev) 560 { 561 struct tpm_chip *chip = dev_get_priv(dev); 562 int rc; 563 564 debug("%s: start\n", __func__); 565 if (chip->is_open) 566 return -EBUSY; 567 rc = tpm_tis_i2c_init(dev); 568 if (rc < 0) 569 chip->is_open = 0; 570 571 return rc; 572 } 573 574 static int tpm_tis_i2c_close(struct udevice *dev) 575 { 576 struct tpm_chip *chip = dev_get_priv(dev); 577 578 if (chip->is_open) { 579 tpm_tis_i2c_release_locality(dev, chip->locality, 1); 580 chip->is_open = 0; 581 chip->vend_dev = 0; 582 } 583 584 return 0; 585 } 586 587 static int tpm_tis_get_desc(struct udevice *dev, char *buf, int size) 588 { 589 struct tpm_chip *chip = dev_get_priv(dev); 590 591 if (size < 50) 592 return -ENOSPC; 593 594 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)", 595 chip->is_open ? "open" : "closed", 596 chip_name[chip->chip_type], 597 chip->vend_dev >> 16); 598 } 599 600 static int tpm_tis_i2c_probe(struct udevice *dev) 601 { 602 struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev); 603 struct tpm_chip *chip = dev_get_priv(dev); 604 605 chip->chip_type = dev_get_driver_data(dev); 606 607 /* TODO: These need to be checked and tuned */ 608 uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS; 609 uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS; 610 uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS; 611 uc_priv->retry_time_ms = TPM_TIMEOUT_MS; 612 613 return 0; 614 } 615 616 static const struct tpm_ops tpm_tis_i2c_ops = { 617 .open = tpm_tis_i2c_open, 618 .close = tpm_tis_i2c_close, 619 .get_desc = tpm_tis_get_desc, 620 .send = tpm_tis_i2c_send, 621 .recv = tpm_tis_i2c_recv, 622 .cleanup = tpm_tis_i2c_cleanup, 623 }; 624 625 static const struct udevice_id tpm_tis_i2c_ids[] = { 626 { .compatible = "infineon,slb9635tt", .data = SLB9635 }, 627 { .compatible = "infineon,slb9645tt", .data = SLB9645 }, 628 { } 629 }; 630 631 U_BOOT_DRIVER(tpm_tis_i2c) = { 632 .name = "tpm_tis_infineon", 633 .id = UCLASS_TPM, 634 .of_match = tpm_tis_i2c_ids, 635 .ops = &tpm_tis_i2c_ops, 636 .probe = tpm_tis_i2c_probe, 637 .priv_auto_alloc_size = sizeof(struct tpm_chip), 638 }; 639