drivers/tpm/tpm_tis_st33zp24_i2c.c

   1 /*
   2  * STMicroelectronics TPM ST33ZP24 I2C UBOOT driver
   3  *
   4  * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
   5  * Author(s): Christophe Ricard <christophe-h.ricard@st.com> for STMicroelectronics.
   6  *
   7  * Description: Device driver for ST33ZP24 I2C TPM TCG.
   8  *
   9  * This device driver implements the TPM interface as defined in
  10  * the TCG TPM Interface Spec version 1.21, revision 1.0 and the
  11  * STMicroelectronics Protocol Stack Specification version 1.2.0.
  12  *
  13  * SPDX-License-Identifier:     GPL-2.0+
  14  */
  15
  16 #include <common.h>
  17 #include <dm.h>
  18 #include <fdtdec.h>
  19 #include <i2c.h>
  20 #include <tpm.h>
  21 #include <errno.h>
  22 #include <linux/types.h>
  23 #include <asm/unaligned.h>
  24
  25 #include "tpm_tis.h"
  26 #include "tpm_internal.h"
  27
  28 #define TPM_ACCESS                      0x0
  29 #define TPM_STS                         0x18
  30 #define TPM_DATA_FIFO                   0x24
  31
  32 #define LOCALITY0                       0
  33
  34 #define TPM_DUMMY_BYTE                  0xAA
  35 #define TPM_ST33ZP24_I2C_SLAVE_ADDR     0x13
  36
  37 #define TPM_WRITE_DIRECTION             0x80
  38
  39 /*
  40  * st33zp24_i2c_write8_reg
  41  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  42  * @param: tpm_register, the tpm tis register where the data should be written
  43  * @param: tpm_data, the tpm_data to write inside the tpm_register
  44  * @param: tpm_size, The length of the data
  45  * @return: Number of byte written successfully else an error code.
  46  */
  47 static int st33zp24_i2c_write8_reg(struct udevice *dev, u8 tpm_register,
  48                                    const u8 *tpm_data, size_t tpm_size)
  49 {
  50         struct tpm_chip_priv *chip_priv = dev_get_uclass_priv(dev);
  51
  52         chip_priv->buf[0] = tpm_register;
  53         memcpy(chip_priv->buf + 1, tpm_data, tpm_size);
  54
  55         return dm_i2c_write(dev, 0, chip_priv->buf, tpm_size + 1);
  56 }
  57
  58 /*
  59 * st33zp24_i2c_read8_reg
  60 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  61 * @param: tpm_register, the tpm tis register where the data should be read
  62 * @param: tpm_data, the TPM response
  63 * @param: tpm_size, tpm TPM response size to read.
  64 * @return: Number of byte read successfully else an error code.
  65 */
  66 static int st33zp24_i2c_read8_reg(struct udevice *dev, u8 tpm_register,
  67                                   u8 *tpm_data, size_t tpm_size)
  68 {
  69         int status;
  70         u8 data;
  71
  72         data = TPM_DUMMY_BYTE;
  73         status = st33zp24_i2c_write8_reg(dev, tpm_register, &data, 1);
  74         if (status < 0)
  75                 return status;
  76
  77         return dm_i2c_read(dev, 0, tpm_data, tpm_size);
  78 }
  79
  80 /*
  81  * st33zp24_i2c_write
  82  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  83  * @param: phy_id, the phy description
  84  * @param: tpm_register, the tpm tis register where the data should be written
  85  * @param: tpm_data, the tpm_data to write inside the tpm_register
  86  * @param: tpm_size, the length of the data
  87  * @return: number of byte written successfully: should be one if success.
  88  */
  89 static int st33zp24_i2c_write(struct udevice *dev, u8 tpm_register,
  90                               const u8 *tpm_data, size_t tpm_size)
  91 {
  92         return st33zp24_i2c_write8_reg(dev, tpm_register | TPM_WRITE_DIRECTION,
  93                                        tpm_data, tpm_size);
  94 }
  95
  96 /*
  97  * st33zp24_i2c_read
  98  * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  99  * @param: phy_id, the phy description
 100  * @param: tpm_register, the tpm tis register where the data should be read
 101  * @param: tpm_data, the TPM response
 102  * @param: tpm_size, tpm TPM response size to read.
 103  * @return: number of byte read successfully: should be one if success.
 104  */
 105 static int st33zp24_i2c_read(struct udevice *dev, u8 tpm_register,
 106                              u8 *tpm_data, size_t tpm_size)
 107 {
 108         return st33zp24_i2c_read8_reg(dev, tpm_register, tpm_data, tpm_size);
 109 }
 110
 111 /*
 112  * st33zp24_i2c_release_locality release the active locality
 113  * @param: chip, the tpm chip description.
 114  */
 115 static void st33zp24_i2c_release_locality(struct udevice *dev)
 116 {
 117         u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
 118
 119         st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
 120 }
 121
 122 /*
 123  * st33zp24_i2c_check_locality if the locality is active
 124  * @param: chip, the tpm chip description
 125  * @return: the active locality or -EACCES.
 126  */
 127 static int st33zp24_i2c_check_locality(struct udevice *dev)
 128 {
 129         struct tpm_chip *chip = dev_get_priv(dev);
 130         u8 data;
 131         u8 status;
 132
 133         status = st33zp24_i2c_read(dev, TPM_ACCESS, &data, 1);
 134         if (!status && (data &
 135                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 136                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 137                 return chip->locality;
 138
 139         return -EACCES;
 140 }
 141
 142 /*
 143  * st33zp24_i2c_request_locality request the TPM locality
 144  * @param: chip, the chip description
 145  * @return: the active locality or negative value.
 146  */
 147 static int st33zp24_i2c_request_locality(struct udevice *dev)
 148 {
 149         struct tpm_chip *chip = dev_get_priv(dev);
 150         unsigned long start, stop;
 151         long ret;
 152         u8 data;
 153
 154         if (st33zp24_i2c_check_locality(dev) == chip->locality)
 155                 return chip->locality;
 156
 157         data = TPM_ACCESS_REQUEST_USE;
 158         ret = st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
 159         if (ret < 0)
 160                 return ret;
 161
 162         /* wait for locality activated */
 163         start = get_timer(0);
 164         stop = chip->timeout_a;
 165         do {
 166                 if (st33zp24_i2c_check_locality(dev) >= 0)
 167                         return chip->locality;
 168                 udelay(TPM_TIMEOUT_MS * 1000);
 169         } while  (get_timer(start) < stop);
 170
 171         return -EACCES;
 172 }
 173
 174 /*
 175  * st33zp24_i2c_status return the TPM_STS register
 176  * @param: chip, the tpm chip description
 177  * @return: the TPM_STS register value.
 178  */
 179 static u8 st33zp24_i2c_status(struct udevice *dev)
 180 {
 181         u8 data;
 182
 183         st33zp24_i2c_read(dev, TPM_STS, &data, 1);
 184
 185         return data;
 186 }
 187
 188 /*
 189  * st33zp24_i2c_get_burstcount return the burstcount address 0x19 0x1A
 190  * @param: chip, the chip description
 191  * return: the burstcount or -TPM_DRIVER_ERR in case of error.
 192  */
 193 static int st33zp24_i2c_get_burstcount(struct udevice *dev)
 194 {
 195         struct tpm_chip *chip = dev_get_priv(dev);
 196         unsigned long start, stop;
 197         int burstcnt, status;
 198         u8 tpm_reg, temp;
 199
 200         /* wait for burstcount */
 201         start = get_timer(0);
 202         stop = chip->timeout_d;
 203         do {
 204                 tpm_reg = TPM_STS + 1;
 205                 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
 206                 if (status < 0)
 207                         return -EBUSY;
 208
 209                 tpm_reg = TPM_STS + 2;
 210                 burstcnt = temp;
 211                 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
 212                 if (status < 0)
 213                         return -EBUSY;
 214
 215                 burstcnt |= temp << 8;
 216                 if (burstcnt)
 217                         return burstcnt;
 218                 udelay(TIS_SHORT_TIMEOUT_MS * 1000);
 219         } while (get_timer(start) < stop);
 220
 221         return -EBUSY;
 222 }
 223
 224 /*
 225  * st33zp24_i2c_cancel, cancel the current command execution or
 226  * set STS to COMMAND READY.
 227  * @param: chip, tpm_chip description.
 228  */
 229 static void st33zp24_i2c_cancel(struct udevice *dev)
 230 {
 231         u8 data;
 232
 233         data = TPM_STS_COMMAND_READY;
 234         st33zp24_i2c_write(dev, TPM_STS, &data, 1);
 235 }
 236
 237 /*
 238  * st33zp24_i2c_wait_for_stat wait for a TPM_STS value
 239  * @param: chip, the tpm chip description
 240  * @param: mask, the value mask to wait
 241  * @param: timeout, the timeout
 242  * @param: status,
 243  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 244  */
 245 static int st33zp24_i2c_wait_for_stat(struct udevice *dev, u8 mask,
 246                                       unsigned long timeout, int *status)
 247 {
 248         unsigned long start, stop;
 249
 250         /* Check current status */
 251         *status = st33zp24_i2c_status(dev);
 252         if ((*status & mask) == mask)
 253                 return 0;
 254
 255         start = get_timer(0);
 256         stop = timeout;
 257         do {
 258                 udelay(TPM_TIMEOUT_MS * 1000);
 259                 *status = st33zp24_i2c_status(dev);
 260                 if ((*status & mask) == mask)
 261                         return 0;
 262         } while (get_timer(start) < stop);
 263
 264         return -ETIME;
 265 }
 266
 267 /*
 268  * st33zp24_i2c_recv_data receive data
 269  * @param: chip, the tpm chip description
 270  * @param: buf, the buffer where the data are received
 271  * @param: count, the number of data to receive
 272  * @return: the number of bytes read from TPM FIFO.
 273  */
 274 static int st33zp24_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
 275 {
 276         struct tpm_chip *chip = dev_get_priv(dev);
 277         int size = 0, burstcnt, len, ret, status;
 278
 279         while (size < count &&
 280                st33zp24_i2c_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 281                                 chip->timeout_c, &status) == 0) {
 282                 burstcnt = st33zp24_i2c_get_burstcount(dev);
 283                 if (burstcnt < 0)
 284                         return burstcnt;
 285                 len = min_t(int, burstcnt, count - size);
 286                 ret = st33zp24_i2c_read(dev, TPM_DATA_FIFO, buf + size, len);
 287                 if (ret < 0)
 288                         return ret;
 289
 290                 size += len;
 291         }
 292
 293         return size;
 294 }
 295
 296 /*
 297  * st33zp24_i2c_recv received TPM response through TPM phy.
 298  * @param: chip, tpm_chip description.
 299  * @param: buf, the buffer to store data.
 300  * @param: count, the number of bytes that can received (sizeof buf).
 301  * @return: Returns zero in case of success else -EIO.
 302  */
 303 static int st33zp24_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
 304 {
 305         struct tpm_chip *chip = dev_get_priv(dev);
 306         int size, expected;
 307
 308         if (!chip)
 309                 return -ENODEV;
 310
 311         if (count < TPM_HEADER_SIZE) {
 312                 size = -EIO;
 313                 goto out;
 314         }
 315
 316         size = st33zp24_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
 317         if (size < TPM_HEADER_SIZE) {
 318                 debug("TPM error, unable to read header\n");
 319                 goto out;
 320         }
 321
 322         expected = get_unaligned_be32(buf + 2);
 323         if (expected > count) {
 324                 size = -EIO;
 325                 goto out;
 326         }
 327
 328         size += st33zp24_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
 329                                    expected - TPM_HEADER_SIZE);
 330         if (size < expected) {
 331                 debug("TPM error, unable to read remaining bytes of result\n");
 332                 size = -EIO;
 333                 goto out;
 334         }
 335
 336 out:
 337         st33zp24_i2c_cancel(dev);
 338         st33zp24_i2c_release_locality(dev);
 339
 340         return size;
 341 }
 342
 343 /*
 344  * st33zp24_i2c_send send TPM commands through TPM phy.
 345  * @param: chip, tpm_chip description.
 346  * @param: buf, the buffer to send.
 347  * @param: len, the number of bytes to send.
 348  * @return: Returns zero in case of success else the negative error code.
 349  */
 350 static int st33zp24_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
 351 {
 352         struct tpm_chip *chip = dev_get_priv(dev);
 353         u32 i, size;
 354         int burstcnt, ret, status;
 355         u8 data, tpm_stat;
 356
 357         if (!chip)
 358                 return -ENODEV;
 359         if (len < TPM_HEADER_SIZE)
 360                 return -EIO;
 361
 362         ret = st33zp24_i2c_request_locality(dev);
 363         if (ret < 0)
 364                 return ret;
 365
 366         tpm_stat = st33zp24_i2c_status(dev);
 367         if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
 368                 st33zp24_i2c_cancel(dev);
 369                 if (st33zp24_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
 370                                                chip->timeout_b, &status) < 0) {
 371                         ret = -ETIME;
 372                         goto out_err;
 373                 }
 374         }
 375
 376         for (i = 0; i < len - 1;) {
 377                 burstcnt = st33zp24_i2c_get_burstcount(dev);
 378                 if (burstcnt < 0)
 379                         return burstcnt;
 380
 381                 size = min_t(int, len - i - 1, burstcnt);
 382                 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + i, size);
 383                 if (ret < 0)
 384                         goto out_err;
 385
 386                 i += size;
 387         }
 388
 389         tpm_stat = st33zp24_i2c_status(dev);
 390         if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
 391                 ret = -EIO;
 392                 goto out_err;
 393         }
 394
 395         ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
 396         if (ret < 0)
 397                 goto out_err;
 398
 399         tpm_stat = st33zp24_i2c_status(dev);
 400         if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
 401                 ret = -EIO;
 402                 goto out_err;
 403         }
 404
 405         data = TPM_STS_GO;
 406         ret = st33zp24_i2c_write(dev, TPM_STS, &data, 1);
 407         if (ret < 0)
 408                 goto out_err;
 409
 410         return len;
 411
 412 out_err:
 413         st33zp24_i2c_cancel(dev);
 414         st33zp24_i2c_release_locality(dev);
 415
 416         return ret;
 417 }
 418
 419 static int st33zp24_i2c_cleanup(struct udevice *dev)
 420 {
 421         st33zp24_i2c_cancel(dev);
 422         /*
 423          * The TPM needs some time to clean up here,
 424          * so we sleep rather than keeping the bus busy
 425          */
 426         mdelay(2);
 427         st33zp24_i2c_release_locality(dev);
 428
 429         return 0;
 430 }
 431
 432 static int st33zp24_i2c_init(struct udevice *dev)
 433 {
 434         struct tpm_chip *chip = dev_get_priv(dev);
 435
 436         chip->is_open = 1;
 437
 438         /* Default timeouts - these could move to the device tree */
 439         chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
 440         chip->timeout_b = TIS_LONG_TIMEOUT_MS;
 441         chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
 442         chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
 443
 444         chip->locality = LOCALITY0;
 445
 446         /*
 447          * A timeout query to TPM can be placed here.
 448          * Standard timeout values are used so far
 449          */
 450
 451         return 0;
 452 }
 453
 454 static int st33zp24_i2c_open(struct udevice *dev)
 455 {
 456         struct tpm_chip *chip = dev_get_priv(dev);
 457         int rc;
 458
 459         debug("%s: start\n", __func__);
 460         if (chip->is_open)
 461                 return -EBUSY;
 462
 463         rc = st33zp24_i2c_init(dev);
 464         if (rc < 0)
 465                 chip->is_open = 0;
 466
 467         return rc;
 468 }
 469
 470 static int st33zp24_i2c_close(struct udevice *dev)
 471 {
 472         struct tpm_chip *chip = dev_get_priv(dev);
 473
 474         if (chip->is_open) {
 475                 st33zp24_i2c_release_locality(dev);
 476                 chip->is_open = 0;
 477                 chip->vend_dev = 0;
 478         }
 479
 480         return 0;
 481 }
 482
 483 static int st33zp24_i2c_get_desc(struct udevice *dev, char *buf, int size)
 484 {
 485         struct tpm_chip *chip = dev_get_priv(dev);
 486
 487         if (size < 50)
 488                 return -ENOSPC;
 489
 490         return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
 491                         chip->is_open ? "open" : "closed",
 492                         dev->name,
 493                         chip->vend_dev >> 16);
 494 }
 495
 496 static const struct tpm_ops st33zp24_i2c_tpm_ops = {
 497         .open = st33zp24_i2c_open,
 498         .close = st33zp24_i2c_close,
 499         .recv = st33zp24_i2c_recv,
 500         .send = st33zp24_i2c_send,
 501         .cleanup = st33zp24_i2c_cleanup,
 502         .get_desc = st33zp24_i2c_get_desc,
 503 };
 504
 505 static int st33zp24_i2c_probe(struct udevice *dev)
 506 {
 507         struct tpm_chip *chip = dev_get_priv(dev);
 508
 509         /* Default timeouts */
 510         chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
 511         chip->timeout_b = TIS_LONG_TIMEOUT_MS;
 512         chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
 513         chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
 514
 515         chip->locality = LOCALITY0;
 516
 517         i2c_set_chip_offset_len(dev, 0);
 518
 519         debug("ST33ZP24 I2C TPM from STMicroelectronics found\n");
 520
 521         return 0;
 522 }
 523
 524 static int st33zp24_i2c_remove(struct udevice *dev)
 525 {
 526         st33zp24_i2c_release_locality(dev);
 527
 528         return 0;
 529 }
 530
 531 static const struct udevice_id st33zp24_i2c_ids[] = {
 532         { .compatible = "st,st33zp24-i2c" },
 533         { }
 534 };
 535
 536 U_BOOT_DRIVER(st33zp24_i2c) = {
 537         .name   = "st33zp24-i2c",
 538         .id     = UCLASS_TPM,
 539         .of_match = of_match_ptr(st33zp24_i2c_ids),
 540         .probe  = st33zp24_i2c_probe,
 541         .remove = st33zp24_i2c_remove,
 542         .ops = &st33zp24_i2c_tpm_ops,
 543         .priv_auto_alloc_size = sizeof(struct tpm_chip),
 544 };