diff options
Diffstat (limited to 'src/drivers/i2c/tpm/tpm.c')
| -rw-r--r-- | src/drivers/i2c/tpm/tpm.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/drivers/i2c/tpm/tpm.c b/src/drivers/i2c/tpm/tpm.c index 5e3c0c1bc8..f0f5ca8d6c 100644 --- a/src/drivers/i2c/tpm/tpm.c +++ b/src/drivers/i2c/tpm/tpm.c @@ -46,6 +46,7 @@ #define SLEEP_DURATION 60 /* in usec */ #define SLEEP_DURATION_LONG 210 /* in usec */ #define SLEEP_DURATION_SAFE 750 /* in usec */ +#define SLEEP_DURATION_PROBE_MS 1000 /* in msec */ /* max. number of iterations after I2C NAK for 'long' commands * we need this especially for sending TPM_READY, since the cleanup after the @@ -695,6 +696,47 @@ out: /* Initialization of I2C TPM */ +int tpm_vendor_probe(unsigned bus, uint32_t addr) +{ + struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev); + struct stopwatch sw; + uint8_t buf = 0; + int ret; + long sw_run_duration = SLEEP_DURATION_PROBE_MS; + + tpm_dev->chip_type = UNKNOWN; + tpm_dev->bus = bus; + tpm_dev->addr = addr; + tpm_dev->sleep_short = SLEEP_DURATION_SAFE; + tpm_dev->sleep_long = SLEEP_DURATION_SAFE * 2; + + /* + * Probe TPM. Check if the TPM_ACCESS register's ValidSts bit is set(1) + * If the bit remains clear(0) then claim that init has failed. + */ + stopwatch_init_msecs_expire(&sw, sw_run_duration); + do { + ret = iic_tpm_read(TPM_ACCESS(0), &buf, 1); + if (!ret && (buf & TPM_STS_VALID)) { + sw_run_duration = stopwatch_duration_msecs(&sw); + break; + } + } 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; +} + int tpm_vendor_init(struct tpm_chip *chip, unsigned bus, uint32_t dev_addr) { struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev); |