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 expected, status; 378 int rc; 379 380 status = tpm_tis_i2c_status(dev); 381 if (status == TPM_STS_COMMAND_READY) 382 return -EINTR; 383 if ((status & (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) != 384 (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) 385 return -EAGAIN; 386 387 debug("...got it;\n"); 388 389 /* Read first 10 bytes, including tag, paramsize, and result */ 390 size = tpm_tis_i2c_recv_data(dev, buf, TPM_HEADER_SIZE); 391 if (size < TPM_HEADER_SIZE) { 392 debug("Unable to read header\n"); 393 return size < 0 ? size : -EIO; 394 } 395 396 expected = get_unaligned_be32(buf + TPM_RSP_SIZE_BYTE); 397 if ((size_t)expected > count) { 398 debug("Error size=%x, expected=%x, count=%x\n", size, expected, 399 count); 400 return -ENOSPC; 401 } 402 403 size += tpm_tis_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE], 404 expected - TPM_HEADER_SIZE); 405 if (size < expected) { 406 debug("Unable to read remainder of result\n"); 407 return -ETIMEDOUT; 408 } 409 410 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, chip->timeout_c, 411 &status); 412 if (rc) 413 return rc; 414 if (status & TPM_STS_DATA_AVAIL) { /* Retry? */ 415 debug("Error left over data\n"); 416 return -EIO; 417 } 418 419 return size; 420 } 421 422 static int tpm_tis_i2c_send(struct udevice *dev, const u8 *buf, size_t len) 423 { 424 struct tpm_chip *chip = dev_get_priv(dev); 425 int rc, status; 426 size_t burstcnt; 427 size_t count = 0; 428 int retry = 0; 429 u8 sts = TPM_STS_GO; 430 431 debug("%s: len=%d\n", __func__, len); 432 if (len > TPM_DEV_BUFSIZE) 433 return -E2BIG; /* Command is too long for our tpm, sorry */ 434 435 if (tpm_tis_i2c_request_locality(dev, 0) < 0) 436 return -EBUSY; 437 438 status = tpm_tis_i2c_status(dev); 439 if ((status & TPM_STS_COMMAND_READY) == 0) { 440 rc = tpm_tis_i2c_ready(dev); 441 if (rc) 442 return rc; 443 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY, 444 chip->timeout_b, &status); 445 if (rc) 446 return rc; 447 } 448 449 burstcnt = tpm_tis_i2c_get_burstcount(dev); 450 451 /* burstcount < 0 -> tpm is busy */ 452 if (burstcnt < 0) 453 return burstcnt; 454 455 while (count < len) { 456 udelay(300); 457 if (burstcnt > len - count) 458 burstcnt = len - count; 459 460 #ifdef CONFIG_TPM_TIS_I2C_BURST_LIMITATION 461 if (retry && burstcnt > CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN) 462 burstcnt = CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN; 463 #endif /* CONFIG_TPM_TIS_I2C_BURST_LIMITATION */ 464 465 rc = tpm_tis_i2c_write(dev, TPM_DATA_FIFO(chip->locality), 466 &(buf[count]), burstcnt); 467 if (rc == 0) 468 count += burstcnt; 469 else { 470 debug("%s: error\n", __func__); 471 if (retry++ > 10) 472 return -EIO; 473 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, 474 chip->timeout_c, 475 &status); 476 if (rc) 477 return rc; 478 479 if ((status & TPM_STS_DATA_EXPECT) == 0) 480 return -EIO; 481 } 482 } 483 484 /* Go and do it */ 485 rc = tpm_tis_i2c_write(dev, TPM_STS(chip->locality), &sts, 1); 486 if (rc < 0) 487 return rc; 488 debug("%s: done, rc=%d\n", __func__, rc); 489 490 return len; 491 } 492 493 static int tpm_tis_i2c_cleanup(struct udevice *dev) 494 { 495 struct tpm_chip *chip = dev_get_priv(dev); 496 497 tpm_tis_i2c_ready(dev); 498 /* 499 * The TPM needs some time to clean up here, 500 * so we sleep rather than keeping the bus busy 501 */ 502 mdelay(2); 503 tpm_tis_i2c_release_locality(dev, chip->locality, 0); 504 505 return 0; 506 } 507 508 static int tpm_tis_i2c_init(struct udevice *dev) 509 { 510 struct tpm_chip *chip = dev_get_priv(dev); 511 u32 vendor; 512 u32 expected_did_vid; 513 int rc; 514 515 chip->is_open = 1; 516 517 /* Default timeouts - these could move to the device tree */ 518 chip->timeout_a = TIS_SHORT_TIMEOUT_MS; 519 chip->timeout_b = TIS_LONG_TIMEOUT_MS; 520 chip->timeout_c = TIS_SHORT_TIMEOUT_MS; 521 chip->timeout_d = TIS_SHORT_TIMEOUT_MS; 522 523 rc = tpm_tis_i2c_request_locality(dev, 0); 524 if (rc < 0) 525 return rc; 526 527 /* Read four bytes from DID_VID register */ 528 if (tpm_tis_i2c_read(dev, TPM_DID_VID(0), (uchar *)&vendor, 4) < 0) { 529 tpm_tis_i2c_release_locality(dev, 0, 1); 530 return -EIO; 531 } 532 533 if (chip->chip_type == SLB9635) { 534 vendor = be32_to_cpu(vendor); 535 expected_did_vid = TPM_TIS_I2C_DID_VID_9635; 536 } else { 537 /* device id and byte order has changed for newer i2c tpms */ 538 expected_did_vid = TPM_TIS_I2C_DID_VID_9645; 539 } 540 541 if (chip->chip_type != UNKNOWN && vendor != expected_did_vid) { 542 pr_err("Vendor id did not match! ID was %08x\n", vendor); 543 return -ENODEV; 544 } 545 546 chip->vend_dev = vendor; 547 debug("1.2 TPM (chip type %s device-id 0x%X)\n", 548 chip_name[chip->chip_type], vendor >> 16); 549 550 /* 551 * A timeout query to TPM can be placed here. 552 * Standard timeout values are used so far 553 */ 554 555 return 0; 556 } 557 558 static int tpm_tis_i2c_open(struct udevice *dev) 559 { 560 struct tpm_chip *chip = dev_get_priv(dev); 561 int rc; 562 563 debug("%s: start\n", __func__); 564 if (chip->is_open) 565 return -EBUSY; 566 rc = tpm_tis_i2c_init(dev); 567 if (rc < 0) 568 chip->is_open = 0; 569 570 return rc; 571 } 572 573 static int tpm_tis_i2c_close(struct udevice *dev) 574 { 575 struct tpm_chip *chip = dev_get_priv(dev); 576 577 if (chip->is_open) { 578 tpm_tis_i2c_release_locality(dev, chip->locality, 1); 579 chip->is_open = 0; 580 chip->vend_dev = 0; 581 } 582 583 return 0; 584 } 585 586 static int tpm_tis_get_desc(struct udevice *dev, char *buf, int size) 587 { 588 struct tpm_chip *chip = dev_get_priv(dev); 589 590 if (size < 50) 591 return -ENOSPC; 592 593 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)", 594 chip->is_open ? "open" : "closed", 595 chip_name[chip->chip_type], 596 chip->vend_dev >> 16); 597 } 598 599 static int tpm_tis_i2c_probe(struct udevice *dev) 600 { 601 struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev); 602 struct tpm_chip *chip = dev_get_priv(dev); 603 604 chip->chip_type = dev_get_driver_data(dev); 605 606 /* TODO: These need to be checked and tuned */ 607 uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS; 608 uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS; 609 uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS; 610 uc_priv->retry_time_ms = TPM_TIMEOUT_MS; 611 612 return 0; 613 } 614 615 static const struct tpm_ops tpm_tis_i2c_ops = { 616 .open = tpm_tis_i2c_open, 617 .close = tpm_tis_i2c_close, 618 .get_desc = tpm_tis_get_desc, 619 .send = tpm_tis_i2c_send, 620 .recv = tpm_tis_i2c_recv, 621 .cleanup = tpm_tis_i2c_cleanup, 622 }; 623 624 static const struct udevice_id tpm_tis_i2c_ids[] = { 625 { .compatible = "infineon,slb9635tt", .data = SLB9635 }, 626 { .compatible = "infineon,slb9645tt", .data = SLB9645 }, 627 { } 628 }; 629 630 U_BOOT_DRIVER(tpm_tis_i2c) = { 631 .name = "tpm_tis_infineon", 632 .id = UCLASS_TPM, 633 .of_match = tpm_tis_i2c_ids, 634 .ops = &tpm_tis_i2c_ops, 635 .probe = tpm_tis_i2c_probe, 636 .priv_auto_alloc_size = sizeof(struct tpm_chip), 637 }; 638