drivers/tpm/tpm_tis_st33zp24_i2c.c

   1 /*
   2  * STMicroelectronics TPM ST33ZP24 I2C UBOOT driver
   3  *
   4  * Copyright (C) 2016 STMicroelectronics
   5  *
   6  * Description: Device driver for ST33ZP24 I2C TPM TCG.
   7  *
   8  * This device driver implements the TPM interface as defined in
   9  * the TCG TPM Interface Spec version 1.21, revision 1.0 and the
  10  * STMicroelectronics Protocol Stack Specification version 1.2.0.
  11  *
  12  * SPDX-License-Identifier:     GPL-2.0+
  13  */
  14
  15 #include <common.h>
  16 #include <dm.h>
  17 #include <fdtdec.h>
  18 #include <i2c.h>
  19 #include <tpm.h>
  20 #include <errno.h>
  21 #include <linux/types.h>
  22 #include <asm/unaligned.h>
  23
  24 #include "tpm_tis.h"
  25 #include "tpm_internal.h"
  26
  27 #define TPM_ACCESS                      0x0
  28 #define TPM_STS                         0x18
  29 #define TPM_DATA_FIFO                   0x24
  30
  31 #define LOCALITY0                       0
  32
  33 #define TPM_DUMMY_BYTE                  0xAA
  34 #define TPM_ST33ZP24_I2C_SLAVE_ADDR     0x13
  35
  36 #define TPM_WRITE_DIRECTION             0x80
  37
  38 /*
  39  * st33zp24_i2c_write8_reg
  40  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  41  * @param: tpm_register, the tpm tis register where the data should be written
  42  * @param: tpm_data, the tpm_data to write inside the tpm_register
  43  * @param: tpm_size, The length of the data
  44  * @return: Number of byte written successfully else an error code.
  45  */
  46 static int st33zp24_i2c_write8_reg(struct udevice *dev, u8 tpm_register,
  47                                    const u8 *tpm_data, size_t tpm_size)
  48 {
  49         struct tpm_chip_priv *chip_priv = dev_get_uclass_priv(dev);
  50
  51         chip_priv->buf[0] = tpm_register;
  52         memcpy(chip_priv->buf + 1, tpm_data, tpm_size);
  53
  54         return dm_i2c_write(dev, 0, chip_priv->buf, tpm_size + 1);
  55 }
  56
  57 /*
  58 * st33zp24_i2c_read8_reg
  59 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  60 * @param: tpm_register, the tpm tis register where the data should be read
  61 * @param: tpm_data, the TPM response
  62 * @param: tpm_size, tpm TPM response size to read.
  63 * @return: Number of byte read successfully else an error code.
  64 */
  65 static int st33zp24_i2c_read8_reg(struct udevice *dev, u8 tpm_register,
  66                                   u8 *tpm_data, size_t tpm_size)
  67 {
  68         int status;
  69         u8 data;
  70
  71         data = TPM_DUMMY_BYTE;
  72         status = st33zp24_i2c_write8_reg(dev, tpm_register, &data, 1);
  73         if (status < 0)
  74                 return status;
  75
  76         return dm_i2c_read(dev, 0, tpm_data, tpm_size);
  77 }
  78
  79 /*
  80  * st33zp24_i2c_write
  81  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  82  * @param: phy_id, the phy description
  83  * @param: tpm_register, the tpm tis register where the data should be written
  84  * @param: tpm_data, the tpm_data to write inside the tpm_register
  85  * @param: tpm_size, the length of the data
  86  * @return: number of byte written successfully: should be one if success.
  87  */
  88 static int st33zp24_i2c_write(struct udevice *dev, u8 tpm_register,
  89                               const u8 *tpm_data, size_t tpm_size)
  90 {
  91         return st33zp24_i2c_write8_reg(dev, tpm_register | TPM_WRITE_DIRECTION,
  92                                        tpm_data, tpm_size);
  93 }
  94
  95 /*
  96  * st33zp24_i2c_read
  97  * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  98  * @param: phy_id, the phy description
  99  * @param: tpm_register, the tpm tis register where the data should be read
 100  * @param: tpm_data, the TPM response
 101  * @param: tpm_size, tpm TPM response size to read.
 102  * @return: number of byte read successfully: should be one if success.
 103  */
 104 static int st33zp24_i2c_read(struct udevice *dev, u8 tpm_register,
 105                              u8 *tpm_data, size_t tpm_size)
 106 {
 107         return st33zp24_i2c_read8_reg(dev, tpm_register, tpm_data, tpm_size);
 108 }
 109
 110 /*
 111  * st33zp24_i2c_release_locality release the active locality
 112  * @param: chip, the tpm chip description.
 113  */
 114 static void st33zp24_i2c_release_locality(struct udevice *dev)
 115 {
 116         u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
 117
 118         st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
 119 }
 120
 121 /*
 122  * st33zp24_i2c_check_locality if the locality is active
 123  * @param: chip, the tpm chip description
 124  * @return: the active locality or -EACCES.
 125  */
 126 static int st33zp24_i2c_check_locality(struct udevice *dev)
 127 {
 128         struct tpm_chip *chip = dev_get_priv(dev);
 129         u8 data;
 130         u8 status;
 131
 132         status = st33zp24_i2c_read(dev, TPM_ACCESS, &data, 1);
 133         if (!status && (data &
 134                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 135                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 136                 return chip->locality;
 137
 138         return -EACCES;
 139 }
 140
 141 /*
 142  * st33zp24_i2c_request_locality request the TPM locality
 143  * @param: chip, the chip description
 144  * @return: the active locality or negative value.
 145  */
 146 static int st33zp24_i2c_request_locality(struct udevice *dev)
 147 {
 148         struct tpm_chip *chip = dev_get_priv(dev);
 149         unsigned long start, stop;
 150         long ret;
 151         u8 data;
 152
 153         if (st33zp24_i2c_check_locality(dev) == chip->locality)
 154                 return chip->locality;
 155
 156         data = TPM_ACCESS_REQUEST_USE;
 157         ret = st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
 158         if (ret < 0)
 159                 return ret;
 160
 161         /* wait for locality activated */
 162         start = get_timer(0);
 163         stop = chip->timeout_a;
 164         do {
 165                 if (st33zp24_i2c_check_locality(dev) >= 0)
 166                         return chip->locality;
 167                 udelay(TPM_TIMEOUT_MS * 1000);
 168         } while  (get_timer(start) < stop);
 169
 170         return -EACCES;
 171 }
 172
 173 /*
 174  * st33zp24_i2c_status return the TPM_STS register
 175  * @param: chip, the tpm chip description
 176  * @return: the TPM_STS register value.
 177  */
 178 static u8 st33zp24_i2c_status(struct udevice *dev)
 179 {
 180         u8 data;
 181
 182         st33zp24_i2c_read(dev, TPM_STS, &data, 1);
 183
 184         return data;
 185 }
 186
 187 /*
 188  * st33zp24_i2c_get_burstcount return the burstcount address 0x19 0x1A
 189  * @param: chip, the chip description
 190  * return: the burstcount or -TPM_DRIVER_ERR in case of error.
 191  */
 192 static int st33zp24_i2c_get_burstcount(struct udevice *dev)
 193 {
 194         struct tpm_chip *chip = dev_get_priv(dev);
 195         unsigned long start, stop;
 196         int burstcnt, status;
 197         u8 tpm_reg, temp;
 198
 199         /* wait for burstcount */
 200         start = get_timer(0);
 201         stop = chip->timeout_d;
 202         do {
 203                 tpm_reg = TPM_STS + 1;
 204                 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
 205                 if (status < 0)
 206                         return -EBUSY;
 207
 208                 tpm_reg = TPM_STS + 2;
 209                 burstcnt = temp;
 210                 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
 211                 if (status < 0)
 212                         return -EBUSY;
 213
 214                 burstcnt |= temp << 8;
 215                 if (burstcnt)
 216                         return burstcnt;
 217                 udelay(TIS_SHORT_TIMEOUT_MS * 1000);
 218         } while (get_timer(start) < stop);
 219
 220         return -EBUSY;
 221 }
 222
 223 /*
 224  * st33zp24_i2c_cancel, cancel the current command execution or
 225  * set STS to COMMAND READY.
 226  * @param: chip, tpm_chip description.
 227  */
 228 static void st33zp24_i2c_cancel(struct udevice *dev)
 229 {
 230         u8 data;
 231
 232         data = TPM_STS_COMMAND_READY;
 233         st33zp24_i2c_write(dev, TPM_STS, &data, 1);
 234 }
 235
 236 /*
 237  * st33zp24_i2c_wait_for_stat wait for a TPM_STS value
 238  * @param: chip, the tpm chip description
 239  * @param: mask, the value mask to wait
 240  * @param: timeout, the timeout
 241  * @param: status,
 242  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 243  */
 244 static int st33zp24_i2c_wait_for_stat(struct udevice *dev, u8 mask,
 245                                       unsigned long timeout, int *status)
 246 {
 247         unsigned long start, stop;
 248
 249         /* Check current status */
 250         *status = st33zp24_i2c_status(dev);
 251         if ((*status & mask) == mask)
 252                 return 0;
 253
 254         start = get_timer(0);
 255         stop = timeout;
 256         do {
 257                 udelay(TPM_TIMEOUT_MS * 1000);
 258                 *status = st33zp24_i2c_status(dev);
 259                 if ((*status & mask) == mask)
 260                         return 0;
 261         } while (get_timer(start) < stop);
 262
 263         return -ETIME;
 264 }
 265
 266 /*
 267  * st33zp24_i2c_recv_data receive data
 268  * @param: chip, the tpm chip description
 269  * @param: buf, the buffer where the data are received
 270  * @param: count, the number of data to receive
 271  * @return: the number of bytes read from TPM FIFO.
 272  */
 273 static int st33zp24_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
 274 {
 275         struct tpm_chip *chip = dev_get_priv(dev);
 276         int size = 0, burstcnt, len, ret, status;
 277
 278         while (size < count &&
 279                st33zp24_i2c_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 280                                 chip->timeout_c, &status) == 0) {
 281                 burstcnt = st33zp24_i2c_get_burstcount(dev);
 282                 if (burstcnt < 0)
 283                         return burstcnt;
 284                 len = min_t(int, burstcnt, count - size);
 285                 ret = st33zp24_i2c_read(dev, TPM_DATA_FIFO, buf + size, len);
 286                 if (ret < 0)
 287                         return ret;
 288
 289                 size += len;
 290         }
 291
 292         return size;
 293 }
 294
 295 /*
 296  * st33zp24_i2c_recv received TPM response through TPM phy.
 297  * @param: chip, tpm_chip description.
 298  * @param: buf, the buffer to store data.
 299  * @param: count, the number of bytes that can received (sizeof buf).
 300  * @return: Returns zero in case of success else -EIO.
 301  */
 302 static int st33zp24_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
 303 {
 304         struct tpm_chip *chip = dev_get_priv(dev);
 305         int size, expected;
 306
 307         if (!chip)
 308                 return -ENODEV;
 309
 310         if (count < TPM_HEADER_SIZE) {
 311                 size = -EIO;
 312                 goto out;
 313         }
 314
 315         size = st33zp24_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
 316         if (size < TPM_HEADER_SIZE) {
 317                 debug("TPM error, unable to read header\n");
 318                 goto out;
 319         }
 320
 321         expected = get_unaligned_be32(buf + 2);
 322         if (expected > count) {
 323                 size = -EIO;
 324                 goto out;
 325         }
 326
 327         size += st33zp24_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
 328                                    expected - TPM_HEADER_SIZE);
 329         if (size < expected) {
 330                 debug("TPM error, unable to read remaining bytes of result\n");
 331                 size = -EIO;
 332                 goto out;
 333         }
 334
 335 out:
 336         st33zp24_i2c_cancel(dev);
 337         st33zp24_i2c_release_locality(dev);
 338
 339         return size;
 340 }
 341
 342 /*
 343  * st33zp24_i2c_send send TPM commands through TPM phy.
 344  * @param: chip, tpm_chip description.
 345  * @param: buf, the buffer to send.
 346  * @param: len, the number of bytes to send.
 347  * @return: Returns zero in case of success else the negative error code.
 348  */
 349 static int st33zp24_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
 350 {
 351         struct tpm_chip *chip = dev_get_priv(dev);
 352         u32 i, size;
 353         int burstcnt, ret, status;
 354         u8 data, tpm_stat;
 355
 356         if (!chip)
 357                 return -ENODEV;
 358         if (len < TPM_HEADER_SIZE)
 359                 return -EIO;
 360
 361         ret = st33zp24_i2c_request_locality(dev);
 362         if (ret < 0)
 363                 return ret;
 364
 365         tpm_stat = st33zp24_i2c_status(dev);
 366         if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
 367                 st33zp24_i2c_cancel(dev);
 368                 if (st33zp24_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
 369                                                chip->timeout_b, &status) < 0) {
 370                         ret = -ETIME;
 371                         goto out_err;
 372                 }
 373         }
 374
 375         for (i = 0; i < len - 1;) {
 376                 burstcnt = st33zp24_i2c_get_burstcount(dev);
 377                 if (burstcnt < 0)
 378                         return burstcnt;
 379
 380                 size = min_t(int, len - i - 1, burstcnt);
 381                 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + i, size);
 382                 if (ret < 0)
 383                         goto out_err;
 384
 385                 i += size;
 386         }
 387
 388         tpm_stat = st33zp24_i2c_status(dev);
 389         if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
 390                 ret = -EIO;
 391                 goto out_err;
 392         }
 393
 394         ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
 395         if (ret < 0)
 396                 goto out_err;
 397
 398         tpm_stat = st33zp24_i2c_status(dev);
 399         if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
 400                 ret = -EIO;
 401                 goto out_err;
 402         }
 403
 404         data = TPM_STS_GO;
 405         ret = st33zp24_i2c_write(dev, TPM_STS, &data, 1);
 406         if (ret < 0)
 407                 goto out_err;
 408
 409         return len;
 410
 411 out_err:
 412         st33zp24_i2c_cancel(dev);
 413         st33zp24_i2c_release_locality(dev);
 414
 415         return ret;
 416 }
 417
 418 static int st33zp24_i2c_cleanup(struct udevice *dev)
 419 {
 420         st33zp24_i2c_cancel(dev);
 421         /*
 422          * The TPM needs some time to clean up here,
 423          * so we sleep rather than keeping the bus busy
 424          */
 425         mdelay(2);
 426         st33zp24_i2c_release_locality(dev);
 427
 428         return 0;
 429 }
 430
 431 static int st33zp24_i2c_init(struct udevice *dev)
 432 {
 433         struct tpm_chip *chip = dev_get_priv(dev);
 434
 435         chip->is_open = 1;
 436
 437         /* Default timeouts - these could move to the device tree */
 438         chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
 439         chip->timeout_b = TIS_LONG_TIMEOUT_MS;
 440         chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
 441         chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
 442
 443         chip->locality = LOCALITY0;
 444
 445         /*
 446          * A timeout query to TPM can be placed here.
 447          * Standard timeout values are used so far
 448          */
 449
 450         return 0;
 451 }
 452
 453 static int st33zp24_i2c_open(struct udevice *dev)
 454 {
 455         struct tpm_chip *chip = dev_get_priv(dev);
 456         int rc;
 457
 458         debug("%s: start\n", __func__);
 459         if (chip->is_open)
 460                 return -EBUSY;
 461
 462         rc = st33zp24_i2c_init(dev);
 463         if (rc < 0)
 464                 chip->is_open = 0;
 465
 466         return rc;
 467 }
 468
 469 static int st33zp24_i2c_close(struct udevice *dev)
 470 {
 471         struct tpm_chip *chip = dev_get_priv(dev);
 472
 473         if (chip->is_open) {
 474                 st33zp24_i2c_release_locality(dev);
 475                 chip->is_open = 0;
 476                 chip->vend_dev = 0;
 477         }
 478
 479         return 0;
 480 }
 481
 482 static int st33zp24_i2c_get_desc(struct udevice *dev, char *buf, int size)
 483 {
 484         struct tpm_chip *chip = dev_get_priv(dev);
 485
 486         if (size < 50)
 487                 return -ENOSPC;
 488
 489         return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
 490                         chip->is_open ? "open" : "closed",
 491                         dev->name,
 492                         chip->vend_dev >> 16);
 493 }
 494
 495 static const struct tpm_ops st33zp24_i2c_tpm_ops = {
 496         .open = st33zp24_i2c_open,
 497         .close = st33zp24_i2c_close,
 498         .recv = st33zp24_i2c_recv,
 499         .send = st33zp24_i2c_send,
 500         .cleanup = st33zp24_i2c_cleanup,
 501         .get_desc = st33zp24_i2c_get_desc,
 502 };
 503
 504 static int st33zp24_i2c_probe(struct udevice *dev)
 505 {
 506         struct tpm_chip *chip = dev_get_priv(dev);
 507
 508         /* Default timeouts */
 509         chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
 510         chip->timeout_b = TIS_LONG_TIMEOUT_MS;
 511         chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
 512         chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
 513
 514         chip->locality = LOCALITY0;
 515
 516         i2c_set_chip_offset_len(dev, 0);
 517
 518         debug("ST33ZP24 I2C TPM from STMicroelectronics found\n");
 519
 520         return 0;
 521 }
 522
 523 static int st33zp24_i2c_remove(struct udevice *dev)
 524 {
 525         st33zp24_i2c_release_locality(dev);
 526
 527         return 0;
 528 }
 529
 530 static const struct udevice_id st33zp24_i2c_ids[] = {
 531         { .compatible = "st,st33zp24-i2c" },
 532         { }
 533 };
 534
 535 U_BOOT_DRIVER(st33zp24_i2c) = {
 536         .name   = "st33zp24-i2c",
 537         .id     = UCLASS_TPM,
 538         .of_match = of_match_ptr(st33zp24_i2c_ids),
 539         .probe  = st33zp24_i2c_probe,
 540         .remove = st33zp24_i2c_remove,
 541         .ops = &st33zp24_i2c_tpm_ops,
 542         .priv_auto_alloc_size = sizeof(struct tpm_chip),
 543 };