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 <dm.h>
  23 #include <fdtdec.h>
  24 #include <i2c.h>
  25 #include <log.h>
  26 #include <time.h>
  27 #include <tpm-v1.h>
  28 #include <linux/delay.h>
  29 #include <linux/errno.h>
  30 #include <linux/compiler.h>
  31 #include <linux/printk.h>
  32 #include <linux/types.h>
  33 #include <linux/unaligned/be_byteshift.h>
  34
  35 #include "tpm_tis.h"
  36 #include "tpm_internal.h"
  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_INFINEON_ACCESS(l)                  (0x0000 | ((l) << 4))
  55 #define TPM_INFINEON_STS(l)                     (0x0001 | ((l) << 4))
  56 #define TPM_INFINEON_DATA_FIFO(l)               (0x0005 | ((l) << 4))
  57 #define TPM_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_INFINEON_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_i2c_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_i2c_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      = sizeof(struct tpm_chip),
 638 };