drivers/tpm/tpm_tis_infineon.c

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