drivers/char/tpm/tpm_i2c

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This source file includes following definitions.
iic_tpm_read
iic_tpm_write_generic
iic_tpm_write
iic_tpm_write_long
check_locality
release_locality
request_locality
tpm_tis_i2c_status
tpm_tis_i2c_ready
get_burstcount
wait_for_stat
recv_data
tpm_tis_i2c_recv
tpm_tis_i2c_send
tpm_tis_i2c_req_canceled
tpm_tis_i2c_init
tpm_tis_i2c_probe
tpm_tis_i2c_remove
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012,2013 Infineon Technologies
   4  *
   5  * Authors:
   6  * Peter Huewe <peter.huewe@infineon.com>
   7  *
   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 original tpm_tis device driver from Leendert van
  16  * Dorn and Kyleen Hall.
  17  */
  18 #include <linux/i2c.h>
  19 #include <linux/module.h>
  20 #include <linux/wait.h>
  21 #include "tpm.h"
  22 
  23 #define TPM_I2C_INFINEON_BUFSIZE 1260
  24 
  25 /* max. number of iterations after I2C NAK */
  26 #define MAX_COUNT 3
  27 
  28 #define SLEEP_DURATION_LOW 55
  29 #define SLEEP_DURATION_HI 65
  30 
  31 /* max. number of iterations after I2C NAK for 'long' commands
  32  * we need this especially for sending TPM_READY, since the cleanup after the
  33  * transtion to the ready state may take some time, but it is unpredictable
  34  * how long it will take.
  35  */
  36 #define MAX_COUNT_LONG 50
  37 
  38 #define SLEEP_DURATION_LONG_LOW 200
  39 #define SLEEP_DURATION_LONG_HI 220
  40 
  41 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
  42 #define SLEEP_DURATION_RESET_LOW 2400
  43 #define SLEEP_DURATION_RESET_HI 2600
  44 
  45 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
  46 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
  47 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
  48 
  49 /* expected value for DIDVID register */
  50 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
  51 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
  52 
  53 enum i2c_chip_type {
  54         SLB9635,
  55         SLB9645,
  56         UNKNOWN,
  57 };
  58 
  59 struct tpm_inf_dev {
  60         struct i2c_client *client;
  61         int locality;
  62         /* In addition to the data itself, the buffer must fit the 7-bit I2C
  63          * address and the direction bit.
  64          */
  65         u8 buf[TPM_I2C_INFINEON_BUFSIZE + 1];
  66         struct tpm_chip *chip;
  67         enum i2c_chip_type chip_type;
  68         unsigned int adapterlimit;
  69 };
  70 
  71 static struct tpm_inf_dev tpm_dev;
  72 
  73 /*
  74  * iic_tpm_read() - read from TPM register
  75  * @addr: register address to read from
  76  * @buffer: provided by caller
  77  * @len: number of bytes to read
  78  *
  79  * Read len bytes from TPM register and put them into
  80  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
  81  *
  82  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
  83  * values have to be swapped.
  84  *
  85  * NOTE: We can't unfortunately use the combined read/write functions
  86  * provided by the i2c core as the TPM currently does not support the
  87  * repeated start condition and due to it's special requirements.
  88  * The i2c_smbus* functions do not work for this chip.
  89  *
  90  * Return -EIO on error, 0 on success.
  91  */
  92 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
  93 {
  94 
  95         struct i2c_msg msg1 = {
  96                 .addr = tpm_dev.client->addr,
  97                 .len = 1,
  98                 .buf = &addr
  99         };
 100         struct i2c_msg msg2 = {
 101                 .addr = tpm_dev.client->addr,
 102                 .flags = I2C_M_RD,
 103                 .len = len,
 104                 .buf = buffer
 105         };
 106         struct i2c_msg msgs[] = {msg1, msg2};
 107 
 108         int rc = 0;
 109         int count;
 110         unsigned int msglen = len;
 111 
 112         /* Lock the adapter for the duration of the whole sequence. */
 113         if (!tpm_dev.client->adapter->algo->master_xfer)
 114                 return -EOPNOTSUPP;
 115         i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 116 
 117         if (tpm_dev.chip_type == SLB9645) {
 118                 /* use a combined read for newer chips
 119                  * unfortunately the smbus functions are not suitable due to
 120                  * the 32 byte limit of the smbus.
 121                  * retries should usually not be needed, but are kept just to
 122                  * be on the safe side.
 123                  */
 124                 for (count = 0; count < MAX_COUNT; count++) {
 125                         rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
 126                         if (rc > 0)
 127                                 break;  /* break here to skip sleep */
 128                         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 129                 }
 130         } else {
 131                 /* Expect to send one command message and one data message, but
 132                  * support looping over each or both if necessary.
 133                  */
 134                 while (len > 0) {
 135                         /* slb9635 protocol should work in all cases */
 136                         for (count = 0; count < MAX_COUNT; count++) {
 137                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 138                                                     &msg1, 1);
 139                                 if (rc > 0)
 140                                         break;  /* break here to skip sleep */
 141 
 142                                 usleep_range(SLEEP_DURATION_LOW,
 143                                              SLEEP_DURATION_HI);
 144                         }
 145 
 146                         if (rc <= 0)
 147                                 goto out;
 148 
 149                         /* After the TPM has successfully received the register
 150                          * address it needs some time, thus we're sleeping here
 151                          * again, before retrieving the data
 152                          */
 153                         for (count = 0; count < MAX_COUNT; count++) {
 154                                 if (tpm_dev.adapterlimit) {
 155                                         msglen = min_t(unsigned int,
 156                                                        tpm_dev.adapterlimit,
 157                                                        len);
 158                                         msg2.len = msglen;
 159                                 }
 160                                 usleep_range(SLEEP_DURATION_LOW,
 161                                              SLEEP_DURATION_HI);
 162                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 163                                                     &msg2, 1);
 164                                 if (rc > 0) {
 165                                         /* Since len is unsigned, make doubly
 166                                          * sure we do not underflow it.
 167                                          */
 168                                         if (msglen > len)
 169                                                 len = 0;
 170                                         else
 171                                                 len -= msglen;
 172                                         msg2.buf += msglen;
 173                                         break;
 174                                 }
 175                                 /* If the I2C adapter rejected the request (e.g
 176                                  * when the quirk read_max_len < len) fall back
 177                                  * to a sane minimum value and try again.
 178                                  */
 179                                 if (rc == -EOPNOTSUPP)
 180                                         tpm_dev.adapterlimit =
 181                                                         I2C_SMBUS_BLOCK_MAX;
 182                         }
 183 
 184                         if (rc <= 0)
 185                                 goto out;
 186                 }
 187         }
 188 
 189 out:
 190         i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 191         /* take care of 'guard time' */
 192         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 193 
 194         /* __i2c_transfer returns the number of successfully transferred
 195          * messages.
 196          * So rc should be greater than 0 here otherwise we have an error.
 197          */
 198         if (rc <= 0)
 199                 return -EIO;
 200 
 201         return 0;
 202 }
 203 
 204 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 205                                  unsigned int sleep_low,
 206                                  unsigned int sleep_hi, u8 max_count)
 207 {
 208         int rc = -EIO;
 209         int count;
 210 
 211         struct i2c_msg msg1 = {
 212                 .addr = tpm_dev.client->addr,
 213                 .len = len + 1,
 214                 .buf = tpm_dev.buf
 215         };
 216 
 217         if (len > TPM_I2C_INFINEON_BUFSIZE)
 218                 return -EINVAL;
 219 
 220         if (!tpm_dev.client->adapter->algo->master_xfer)
 221                 return -EOPNOTSUPP;
 222         i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 223 
 224         /* prepend the 'register address' to the buffer */
 225         tpm_dev.buf[0] = addr;
 226         memcpy(&(tpm_dev.buf[1]), buffer, len);
 227 
 228         /*
 229          * NOTE: We have to use these special mechanisms here and unfortunately
 230          * cannot rely on the standard behavior of i2c_transfer.
 231          * Even for newer chips the smbus functions are not
 232          * suitable due to the 32 byte limit of the smbus.
 233          */
 234         for (count = 0; count < max_count; count++) {
 235                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 236                 if (rc > 0)
 237                         break;
 238                 usleep_range(sleep_low, sleep_hi);
 239         }
 240 
 241         i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 242         /* take care of 'guard time' */
 243         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 244 
 245         /* __i2c_transfer returns the number of successfully transferred
 246          * messages.
 247          * So rc should be greater than 0 here otherwise we have an error.
 248          */
 249         if (rc <= 0)
 250                 return -EIO;
 251 
 252         return 0;
 253 }
 254 
 255 /*
 256  * iic_tpm_write() - write to TPM register
 257  * @addr: register address to write to
 258  * @buffer: containing data to be written
 259  * @len: number of bytes to write
 260  *
 261  * Write len bytes from provided buffer to TPM register (little
 262  * endian format, i.e. buffer[0] is written as first byte).
 263  *
 264  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 265  * values have to be swapped.
 266  *
 267  * NOTE: use this function instead of the iic_tpm_write_generic function.
 268  *
 269  * Return -EIO on error, 0 on success
 270  */
 271 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
 272 {
 273         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
 274                                      SLEEP_DURATION_HI, MAX_COUNT);
 275 }
 276 
 277 /*
 278  * This function is needed especially for the cleanup situation after
 279  * sending TPM_READY
 280  * */
 281 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
 282 {
 283         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
 284                                      SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
 285 }
 286 
 287 enum tis_access {
 288         TPM_ACCESS_VALID = 0x80,
 289         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
 290         TPM_ACCESS_REQUEST_PENDING = 0x04,
 291         TPM_ACCESS_REQUEST_USE = 0x02,
 292 };
 293 
 294 enum tis_status {
 295         TPM_STS_VALID = 0x80,
 296         TPM_STS_COMMAND_READY = 0x40,
 297         TPM_STS_GO = 0x20,
 298         TPM_STS_DATA_AVAIL = 0x10,
 299         TPM_STS_DATA_EXPECT = 0x08,
 300 };
 301 
 302 enum tis_defaults {
 303         TIS_SHORT_TIMEOUT = 750,        /* ms */
 304         TIS_LONG_TIMEOUT = 2000,        /* 2 sec */
 305 };
 306 
 307 #define TPM_ACCESS(l)                   (0x0000 | ((l) << 4))
 308 #define TPM_STS(l)                      (0x0001 | ((l) << 4))
 309 #define TPM_DATA_FIFO(l)                (0x0005 | ((l) << 4))
 310 #define TPM_DID_VID(l)                  (0x0006 | ((l) << 4))
 311 
 312 static bool check_locality(struct tpm_chip *chip, int loc)
 313 {
 314         u8 buf;
 315         int rc;
 316 
 317         rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
 318         if (rc < 0)
 319                 return false;
 320 
 321         if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 322             (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 323                 tpm_dev.locality = loc;
 324                 return true;
 325         }
 326 
 327         return false;
 328 }
 329 
 330 /* implementation similar to tpm_tis */
 331 static void release_locality(struct tpm_chip *chip, int loc, int force)
 332 {
 333         u8 buf;
 334         if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
 335                 return;
 336 
 337         if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 338             (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
 339                 buf = TPM_ACCESS_ACTIVE_LOCALITY;
 340                 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 341         }
 342 }
 343 
 344 static int request_locality(struct tpm_chip *chip, int loc)
 345 {
 346         unsigned long stop;
 347         u8 buf = TPM_ACCESS_REQUEST_USE;
 348 
 349         if (check_locality(chip, loc))
 350                 return loc;
 351 
 352         iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 353 
 354         /* wait for burstcount */
 355         stop = jiffies + chip->timeout_a;
 356         do {
 357                 if (check_locality(chip, loc))
 358                         return loc;
 359                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 360         } while (time_before(jiffies, stop));
 361 
 362         return -ETIME;
 363 }
 364 
 365 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
 366 {
 367         /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
 368         u8 buf = 0xFF;
 369         u8 i = 0;
 370 
 371         do {
 372                 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
 373                         return 0;
 374 
 375                 i++;
 376         /* if locallity is set STS should not be 0xFF */
 377         } while ((buf == 0xFF) && i < 10);
 378 
 379         return buf;
 380 }
 381 
 382 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
 383 {
 384         /* this causes the current command to be aborted */
 385         u8 buf = TPM_STS_COMMAND_READY;
 386         iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
 387 }
 388 
 389 static ssize_t get_burstcount(struct tpm_chip *chip)
 390 {
 391         unsigned long stop;
 392         ssize_t burstcnt;
 393         u8 buf[3];
 394 
 395         /* wait for burstcount */
 396         /* which timeout value, spec has 2 answers (c & d) */
 397         stop = jiffies + chip->timeout_d;
 398         do {
 399                 /* Note: STS is little endian */
 400                 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
 401                         burstcnt = 0;
 402                 else
 403                         burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
 404 
 405                 if (burstcnt)
 406                         return burstcnt;
 407 
 408                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 409         } while (time_before(jiffies, stop));
 410         return -EBUSY;
 411 }
 412 
 413 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 414                          int *status)
 415 {
 416         unsigned long stop;
 417 
 418         /* check current status */
 419         *status = tpm_tis_i2c_status(chip);
 420         if ((*status != 0xFF) && (*status & mask) == mask)
 421                 return 0;
 422 
 423         stop = jiffies + timeout;
 424         do {
 425                 /* since we just checked the status, give the TPM some time */
 426                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 427                 *status = tpm_tis_i2c_status(chip);
 428                 if ((*status & mask) == mask)
 429                         return 0;
 430 
 431         } while (time_before(jiffies, stop));
 432 
 433         return -ETIME;
 434 }
 435 
 436 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 437 {
 438         size_t size = 0;
 439         ssize_t burstcnt;
 440         u8 retries = 0;
 441         int rc;
 442 
 443         while (size < count) {
 444                 burstcnt = get_burstcount(chip);
 445 
 446                 /* burstcnt < 0 = TPM is busy */
 447                 if (burstcnt < 0)
 448                         return burstcnt;
 449 
 450                 /* limit received data to max. left */
 451                 if (burstcnt > (count - size))
 452                         burstcnt = count - size;
 453 
 454                 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
 455                                   &(buf[size]), burstcnt);
 456                 if (rc == 0)
 457                         size += burstcnt;
 458                 else if (rc < 0)
 459                         retries++;
 460 
 461                 /* avoid endless loop in case of broken HW */
 462                 if (retries > MAX_COUNT_LONG)
 463                         return -EIO;
 464         }
 465         return size;
 466 }
 467 
 468 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 469 {
 470         int size = 0;
 471         int status;
 472         u32 expected;
 473 
 474         if (count < TPM_HEADER_SIZE) {
 475                 size = -EIO;
 476                 goto out;
 477         }
 478 
 479         /* read first 10 bytes, including tag, paramsize, and result */
 480         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 481         if (size < TPM_HEADER_SIZE) {
 482                 dev_err(&chip->dev, "Unable to read header\n");
 483                 goto out;
 484         }
 485 
 486         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 487         if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
 488                 size = -EIO;
 489                 goto out;
 490         }
 491 
 492         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 493                           expected - TPM_HEADER_SIZE);
 494         if (size < expected) {
 495                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 496                 size = -ETIME;
 497                 goto out;
 498         }
 499 
 500         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 501         if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
 502                 dev_err(&chip->dev, "Error left over data\n");
 503                 size = -EIO;
 504                 goto out;
 505         }
 506 
 507 out:
 508         tpm_tis_i2c_ready(chip);
 509         /* The TPM needs some time to clean up here,
 510          * so we sleep rather than keeping the bus busy
 511          */
 512         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 513         release_locality(chip, tpm_dev.locality, 0);
 514         return size;
 515 }
 516 
 517 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
 518 {
 519         int rc, status;
 520         ssize_t burstcnt;
 521         size_t count = 0;
 522         u8 retries = 0;
 523         u8 sts = TPM_STS_GO;
 524 
 525         if (len > TPM_I2C_INFINEON_BUFSIZE)
 526                 return -E2BIG;
 527 
 528         if (request_locality(chip, 0) < 0)
 529                 return -EBUSY;
 530 
 531         status = tpm_tis_i2c_status(chip);
 532         if ((status & TPM_STS_COMMAND_READY) == 0) {
 533                 tpm_tis_i2c_ready(chip);
 534                 if (wait_for_stat
 535                     (chip, TPM_STS_COMMAND_READY,
 536                      chip->timeout_b, &status) < 0) {
 537                         rc = -ETIME;
 538                         goto out_err;
 539                 }
 540         }
 541 
 542         while (count < len - 1) {
 543                 burstcnt = get_burstcount(chip);
 544 
 545                 /* burstcnt < 0 = TPM is busy */
 546                 if (burstcnt < 0)
 547                         return burstcnt;
 548 
 549                 if (burstcnt > (len - 1 - count))
 550                         burstcnt = len - 1 - count;
 551 
 552                 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
 553                                    &(buf[count]), burstcnt);
 554                 if (rc == 0)
 555                         count += burstcnt;
 556                 else if (rc < 0)
 557                         retries++;
 558 
 559                 /* avoid endless loop in case of broken HW */
 560                 if (retries > MAX_COUNT_LONG) {
 561                         rc = -EIO;
 562                         goto out_err;
 563                 }
 564 
 565                 wait_for_stat(chip, TPM_STS_VALID,
 566                               chip->timeout_c, &status);
 567 
 568                 if ((status & TPM_STS_DATA_EXPECT) == 0) {
 569                         rc = -EIO;
 570                         goto out_err;
 571                 }
 572         }
 573 
 574         /* write last byte */
 575         iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
 576         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 577         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 578                 rc = -EIO;
 579                 goto out_err;
 580         }
 581 
 582         /* go and do it */
 583         iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
 584 
 585         return 0;
 586 out_err:
 587         tpm_tis_i2c_ready(chip);
 588         /* The TPM needs some time to clean up here,
 589          * so we sleep rather than keeping the bus busy
 590          */
 591         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 592         release_locality(chip, tpm_dev.locality, 0);
 593         return rc;
 594 }
 595 
 596 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 597 {
 598         return (status == TPM_STS_COMMAND_READY);
 599 }
 600 
 601 static const struct tpm_class_ops tpm_tis_i2c = {
 602         .flags = TPM_OPS_AUTO_STARTUP,
 603         .status = tpm_tis_i2c_status,
 604         .recv = tpm_tis_i2c_recv,
 605         .send = tpm_tis_i2c_send,
 606         .cancel = tpm_tis_i2c_ready,
 607         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 608         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 609         .req_canceled = tpm_tis_i2c_req_canceled,
 610 };
 611 
 612 static int tpm_tis_i2c_init(struct device *dev)
 613 {
 614         u32 vendor;
 615         int rc = 0;
 616         struct tpm_chip *chip;
 617 
 618         chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
 619         if (IS_ERR(chip))
 620                 return PTR_ERR(chip);
 621 
 622         /* Default timeouts */
 623         chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 624         chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 625         chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 626         chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 627 
 628         if (request_locality(chip, 0) != 0) {
 629                 dev_err(dev, "could not request locality\n");
 630                 rc = -ENODEV;
 631                 goto out_err;
 632         }
 633 
 634         /* read four bytes from DID_VID register */
 635         if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
 636                 dev_err(dev, "could not read vendor id\n");
 637                 rc = -EIO;
 638                 goto out_release;
 639         }
 640 
 641         if (vendor == TPM_TIS_I2C_DID_VID_9645) {
 642                 tpm_dev.chip_type = SLB9645;
 643         } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
 644                 tpm_dev.chip_type = SLB9635;
 645         } else {
 646                 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
 647                 rc = -ENODEV;
 648                 goto out_release;
 649         }
 650 
 651         dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
 652 
 653         tpm_dev.chip = chip;
 654 
 655         return tpm_chip_register(chip);
 656 out_release:
 657         release_locality(chip, tpm_dev.locality, 1);
 658         tpm_dev.client = NULL;
 659 out_err:
 660         return rc;
 661 }
 662 
 663 static const struct i2c_device_id tpm_tis_i2c_table[] = {
 664         {"tpm_i2c_infineon"},
 665         {"slb9635tt"},
 666         {"slb9645tt"},
 667         {},
 668 };
 669 
 670 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
 671 
 672 #ifdef CONFIG_OF
 673 static const struct of_device_id tpm_tis_i2c_of_match[] = {
 674         {.compatible = "infineon,tpm_i2c_infineon"},
 675         {.compatible = "infineon,slb9635tt"},
 676         {.compatible = "infineon,slb9645tt"},
 677         {},
 678 };
 679 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
 680 #endif
 681 
 682 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
 683 
 684 static int tpm_tis_i2c_probe(struct i2c_client *client,
 685                              const struct i2c_device_id *id)
 686 {
 687         int rc;
 688         struct device *dev = &(client->dev);
 689 
 690         if (tpm_dev.client != NULL) {
 691                 dev_err(dev, "This driver only supports one client at a time\n");
 692                 return -EBUSY;  /* We only support one client */
 693         }
 694 
 695         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 696                 dev_err(dev, "no algorithms associated to the i2c bus\n");
 697                 return -ENODEV;
 698         }
 699 
 700         tpm_dev.client = client;
 701         rc = tpm_tis_i2c_init(&client->dev);
 702         if (rc != 0) {
 703                 tpm_dev.client = NULL;
 704                 rc = -ENODEV;
 705         }
 706         return rc;
 707 }
 708 
 709 static int tpm_tis_i2c_remove(struct i2c_client *client)
 710 {
 711         struct tpm_chip *chip = tpm_dev.chip;
 712 
 713         tpm_chip_unregister(chip);
 714         release_locality(chip, tpm_dev.locality, 1);
 715         tpm_dev.client = NULL;
 716 
 717         return 0;
 718 }
 719 
 720 static struct i2c_driver tpm_tis_i2c_driver = {
 721         .id_table = tpm_tis_i2c_table,
 722         .probe = tpm_tis_i2c_probe,
 723         .remove = tpm_tis_i2c_remove,
 724         .driver = {
 725                    .name = "tpm_i2c_infineon",
 726                    .pm = &tpm_tis_i2c_ops,
 727                    .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
 728                    },
 729 };
 730 
 731 module_i2c_driver(tpm_tis_i2c_driver);
 732 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
 733 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
 734 MODULE_VERSION("2.2.0");
 735 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/char/tpm/tpm_i2c_infineon.c

DEFINITIONS
