diff options
Diffstat (limited to 'src/drivers')
| -rw-r--r-- | src/drivers/i2c/tpm/cr50.c | 148 |
1 files changed, 73 insertions, 75 deletions
diff --git a/src/drivers/i2c/tpm/cr50.c b/src/drivers/i2c/tpm/cr50.c index 9cc9e95ffb..8b0ea32269 100644 --- a/src/drivers/i2c/tpm/cr50.c +++ b/src/drivers/i2c/tpm/cr50.c @@ -170,57 +170,88 @@ static int cr50_i2c_write(struct tpm_chip *chip, return cr50_i2c_wait_tpm_ready(chip); } -static int check_locality(struct tpm_chip *chip, int loc) +/* + * Cr50 processes reset requests asynchronously and consceivably could be busy + * executing a long command and not reacting to the reset pulse for a while. + * + * This function will make sure that the AP does not proceed with boot until + * TPM finished reset processing. + */ +static int process_reset(struct tpm_chip *chip) { - uint8_t mask = TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY; - uint8_t buf; + struct stopwatch sw; + uint8_t access; + + /* + * Locality is released by TPM reset. + * + * If locality is taken at this point, this could be due to the fact + * that the TPM is performing a long operation and has not processed + * reset request yet. We'll wait up to CR50_TIMEOUT_INIT_MS and see if + * it releases locality when reset is processed. + */ + stopwatch_init_msecs_expire(&sw, CR50_TIMEOUT_INIT_MS); + do { + int rv; + const uint8_t mask = + TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY; + + rv = cr50_i2c_read(chip, TPM_ACCESS(0), + &access, sizeof(access)); + if (rv || ((access & mask) == mask)) { + /* + * Don't bombard the chip with traffic, let it keep + * processing the command. + */ + mdelay(2); + continue; + } - if (cr50_i2c_read(chip, TPM_ACCESS(loc), &buf, 1) < 0) - return -1; + printk(BIOS_INFO, "TPM ready after %ld ms\n", + stopwatch_duration_msecs(&sw)); - if ((buf & mask) == mask) { - chip->vendor.locality = loc; - return loc; - } + return 0; + } while (!stopwatch_expired(&sw)); + + printk(BIOS_ERR, + "TPM failed to reset after %ld ms, status: %#x\n", + stopwatch_duration_msecs(&sw), access); return -1; } -static void release_locality(struct tpm_chip *chip, int force) +/* + * Locality could be already claimed (if this is a later coreboot stage and + * the RO did not release it), or not yet claimed, if this is verstage or the + * older RO did release it. + */ +static int claim_locality(struct tpm_chip *chip) { - uint8_t mask = TPM_ACCESS_VALID | TPM_ACCESS_REQUEST_PENDING; - uint8_t addr = TPM_ACCESS(chip->vendor.locality); - uint8_t buf; + uint8_t access; + const uint8_t mask = TPM_ACCESS_VALID | TPM_ACCESS_ACTIVE_LOCALITY; - if (cr50_i2c_read(chip, addr, &buf, 1) < 0) - return; + if (cr50_i2c_read(chip, TPM_ACCESS(0), &access, sizeof(access))) + return -1; - if (force || (buf & mask) == mask) { - buf = TPM_ACCESS_ACTIVE_LOCALITY; - cr50_i2c_write(chip, addr, &buf, 1); + if ((access & mask) == mask) { + printk(BIOS_INFO, "Locality already claimed\n"); + return 0; } - chip->vendor.locality = 0; -} - -static int request_locality(struct tpm_chip *chip, int loc) -{ - uint8_t buf = TPM_ACCESS_REQUEST_USE; - struct stopwatch sw; - - if (check_locality(chip, loc) >= 0) - return loc; + access = TPM_ACCESS_REQUEST_USE; + if (cr50_i2c_write(chip, TPM_ACCESS(0), + &access, sizeof(access))) + return -1; - if (cr50_i2c_write(chip, TPM_ACCESS(loc), &buf, 1) < 0) + if (cr50_i2c_read(chip, TPM_ACCESS(0), &access, sizeof(access))) return -1; - stopwatch_init_msecs_expire(&sw, CR50_TIMEOUT_LONG_MS); - while (check_locality(chip, loc) < 0) { - if (stopwatch_expired(&sw)) - return -1; - mdelay(CR50_TIMEOUT_SHORT_MS); + if ((access & mask) != mask) { + printk(BIOS_INFO, "Failed to claim locality.\n"); + return -1; } - return loc; + + return 0; } /* cr50 requires all 4 bytes of status register to be read */ @@ -419,38 +450,6 @@ static void cr50_vendor_init(struct tpm_chip *chip) int tpm_vendor_probe(unsigned int bus, uint32_t addr) { - struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev); - struct tpm_chip probe_chip; - struct stopwatch sw; - uint8_t buf = 0; - int ret; - long sw_run_duration = CR50_TIMEOUT_INIT_MS; - - tpm_dev->bus = bus; - tpm_dev->addr = addr; - - cr50_vendor_init(&probe_chip); - - /* Wait for TPM_ACCESS register ValidSts bit to be set */ - stopwatch_init_msecs_expire(&sw, sw_run_duration); - do { - ret = cr50_i2c_read(&probe_chip, TPM_ACCESS(0), &buf, 1); - if (!ret && (buf & TPM_STS_VALID)) { - sw_run_duration = stopwatch_duration_msecs(&sw); - break; - } - mdelay(CR50_TIMEOUT_SHORT_MS); - } while (!stopwatch_expired(&sw)); - - printk(BIOS_INFO, - "%s: ValidSts bit %s(%d) in TPM_ACCESS register after %ld ms\n", - __func__, (buf & TPM_STS_VALID) ? "set" : "clear", - (buf & TPM_STS_VALID) >> 7, sw_run_duration); - - /* Claim failure if the ValidSts (bit 7) is clear */ - if (!(buf & TPM_STS_VALID)) - return -1; - return 0; } @@ -469,16 +468,20 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr) cr50_vendor_init(chip); - if (request_locality(chip, 0) != 0) + if (ENV_VERSTAGE || ENV_BOOTBLOCK) + if (process_reset(chip)) + return -1; + + if (claim_locality(chip)) return -1; /* Read four bytes from DID_VID register */ if (cr50_i2c_read(chip, TPM_DID_VID(0), (uint8_t *)&vendor, 4) < 0) - goto out_err; + return -1; if (vendor != CR50_DID_VID) { printk(BIOS_DEBUG, "Vendor ID 0x%08x not recognized\n", vendor); - goto out_err; + return -1; } printk(BIOS_DEBUG, "cr50 TPM 2.0 (i2c %u:0x%02x id 0x%x)\n", @@ -486,13 +489,8 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr) chip->is_open = 1; return 0; - -out_err: - release_locality(chip, 1); - return -1; } void tpm_vendor_cleanup(struct tpm_chip *chip) { - release_locality(chip, 1); } |