drivers/tpm/tpm_tis_infineon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011 Infineon Technologies
   4  *
   5  * Authors:
   6  * Peter Huewe <huewe.external@infineon.com>
   7  *
   8  * Description:
   9  * Device driver for TCG/TCPA TPM (trusted platform module).
  10  * Specifications at www.trustedcomputinggroup.org
  11  *
  12  * This device driver implements the TPM interface as defined in
  13  * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
  14  * Infineon I2C Protocol Stack Specification v0.20.
  15  *
  16  * It is based on the Linux kernel driver tpm.c from Leendert van
  17  * Dorn, Dave Safford, Reiner Sailer, and Kyleen Hall.
  18  *
  19  * Version: 2.1.1
  20  */
  21
  22 #include <common.h>
  23 #include <dm.h>
  24 #include <fdtdec.h>
  25 #include <i2c.h>
  26 #include <log.h>
  27 #include <tpm-v1.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 };