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