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; 307 unsigned int expected; 308 309 if (!chip) 310 return -ENODEV; 311 312 if (count < TPM_HEADER_SIZE) { 313 size = -EIO; 314 goto out; 315 } 316 317 size = st33zp24_i2c_recv_data(dev, buf, TPM_HEADER_SIZE); 318 if (size < TPM_HEADER_SIZE) { 319 debug("TPM error, unable to read header\n"); 320 goto out; 321 } 322 323 expected = get_unaligned_be32(buf + 2); 324 if (expected > count || expected < TPM_HEADER_SIZE) { 325 size = -EIO; 326 goto out; 327 } 328 329 size += st33zp24_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE], 330 expected - TPM_HEADER_SIZE); 331 if (size < expected) { 332 debug("TPM error, unable to read remaining bytes of result\n"); 333 size = -EIO; 334 goto out; 335 } 336 337 out: 338 st33zp24_i2c_cancel(dev); 339 st33zp24_i2c_release_locality(dev); 340 341 return size; 342 } 343 344 /* 345 * st33zp24_i2c_send send TPM commands through TPM phy. 346 * @param: chip, tpm_chip description. 347 * @param: buf, the buffer to send. 348 * @param: len, the number of bytes to send. 349 * @return: Returns zero in case of success else the negative error code. 350 */ 351 static int st33zp24_i2c_send(struct udevice *dev, const u8 *buf, size_t len) 352 { 353 struct tpm_chip *chip = dev_get_priv(dev); 354 u32 i, size; 355 int burstcnt, ret, status; 356 u8 data, tpm_stat; 357 358 if (!chip) 359 return -ENODEV; 360 if (len < TPM_HEADER_SIZE) 361 return -EIO; 362 363 ret = st33zp24_i2c_request_locality(dev); 364 if (ret < 0) 365 return ret; 366 367 tpm_stat = st33zp24_i2c_status(dev); 368 if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) { 369 st33zp24_i2c_cancel(dev); 370 if (st33zp24_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY, 371 chip->timeout_b, &status) < 0) { 372 ret = -ETIME; 373 goto out_err; 374 } 375 } 376 377 for (i = 0; i < len - 1;) { 378 burstcnt = st33zp24_i2c_get_burstcount(dev); 379 if (burstcnt < 0) 380 return burstcnt; 381 382 size = min_t(int, len - i - 1, burstcnt); 383 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + i, size); 384 if (ret < 0) 385 goto out_err; 386 387 i += size; 388 } 389 390 tpm_stat = st33zp24_i2c_status(dev); 391 if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) { 392 ret = -EIO; 393 goto out_err; 394 } 395 396 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + len - 1, 1); 397 if (ret < 0) 398 goto out_err; 399 400 tpm_stat = st33zp24_i2c_status(dev); 401 if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) { 402 ret = -EIO; 403 goto out_err; 404 } 405 406 data = TPM_STS_GO; 407 ret = st33zp24_i2c_write(dev, TPM_STS, &data, 1); 408 if (ret < 0) 409 goto out_err; 410 411 return len; 412 413 out_err: 414 st33zp24_i2c_cancel(dev); 415 st33zp24_i2c_release_locality(dev); 416 417 return ret; 418 } 419 420 static int st33zp24_i2c_cleanup(struct udevice *dev) 421 { 422 st33zp24_i2c_cancel(dev); 423 /* 424 * The TPM needs some time to clean up here, 425 * so we sleep rather than keeping the bus busy 426 */ 427 mdelay(2); 428 st33zp24_i2c_release_locality(dev); 429 430 return 0; 431 } 432 433 static int st33zp24_i2c_init(struct udevice *dev) 434 { 435 struct tpm_chip *chip = dev_get_priv(dev); 436 437 chip->is_open = 1; 438 439 /* Default timeouts - these could move to the device tree */ 440 chip->timeout_a = TIS_SHORT_TIMEOUT_MS; 441 chip->timeout_b = TIS_LONG_TIMEOUT_MS; 442 chip->timeout_c = TIS_SHORT_TIMEOUT_MS; 443 chip->timeout_d = TIS_SHORT_TIMEOUT_MS; 444 445 chip->locality = LOCALITY0; 446 447 /* 448 * A timeout query to TPM can be placed here. 449 * Standard timeout values are used so far 450 */ 451 452 return 0; 453 } 454 455 static int st33zp24_i2c_open(struct udevice *dev) 456 { 457 struct tpm_chip *chip = dev_get_priv(dev); 458 int rc; 459 460 debug("%s: start\n", __func__); 461 if (chip->is_open) 462 return -EBUSY; 463 464 rc = st33zp24_i2c_init(dev); 465 if (rc < 0) 466 chip->is_open = 0; 467 468 return rc; 469 } 470 471 static int st33zp24_i2c_close(struct udevice *dev) 472 { 473 struct tpm_chip *chip = dev_get_priv(dev); 474 475 if (chip->is_open) { 476 st33zp24_i2c_release_locality(dev); 477 chip->is_open = 0; 478 chip->vend_dev = 0; 479 } 480 481 return 0; 482 } 483 484 static int st33zp24_i2c_get_desc(struct udevice *dev, char *buf, int size) 485 { 486 struct tpm_chip *chip = dev_get_priv(dev); 487 488 if (size < 50) 489 return -ENOSPC; 490 491 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)", 492 chip->is_open ? "open" : "closed", 493 dev->name, 494 chip->vend_dev >> 16); 495 } 496 497 static const struct tpm_ops st33zp24_i2c_tpm_ops = { 498 .open = st33zp24_i2c_open, 499 .close = st33zp24_i2c_close, 500 .recv = st33zp24_i2c_recv, 501 .send = st33zp24_i2c_send, 502 .cleanup = st33zp24_i2c_cleanup, 503 .get_desc = st33zp24_i2c_get_desc, 504 }; 505 506 static int st33zp24_i2c_probe(struct udevice *dev) 507 { 508 struct tpm_chip *chip = dev_get_priv(dev); 509 510 /* Default timeouts */ 511 chip->timeout_a = TIS_SHORT_TIMEOUT_MS; 512 chip->timeout_b = TIS_LONG_TIMEOUT_MS; 513 chip->timeout_c = TIS_SHORT_TIMEOUT_MS; 514 chip->timeout_d = TIS_SHORT_TIMEOUT_MS; 515 516 chip->locality = LOCALITY0; 517 518 i2c_set_chip_offset_len(dev, 0); 519 520 debug("ST33ZP24 I2C TPM from STMicroelectronics found\n"); 521 522 return 0; 523 } 524 525 static int st33zp24_i2c_remove(struct udevice *dev) 526 { 527 st33zp24_i2c_release_locality(dev); 528 529 return 0; 530 } 531 532 static const struct udevice_id st33zp24_i2c_ids[] = { 533 { .compatible = "st,st33zp24-i2c" }, 534 { } 535 }; 536 537 U_BOOT_DRIVER(st33zp24_i2c) = { 538 .name = "st33zp24-i2c", 539 .id = UCLASS_TPM, 540 .of_match = of_match_ptr(st33zp24_i2c_ids), 541 .probe = st33zp24_i2c_probe, 542 .remove = st33zp24_i2c_remove, 543 .ops = &st33zp24_i2c_tpm_ops, 544 .priv_auto_alloc_size = sizeof(struct tpm_chip), 545 }; 546