diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/drivers/i2c/tpm/cr50.c | 50 |
1 files changed, 39 insertions, 11 deletions
diff --git a/src/drivers/i2c/tpm/cr50.c b/src/drivers/i2c/tpm/cr50.c index b0d3b29044..19c8f6bcbb 100644 --- a/src/drivers/i2c/tpm/cr50.c +++ b/src/drivers/i2c/tpm/cr50.c @@ -456,10 +456,44 @@ int tpm_vendor_probe(unsigned int bus, uint32_t addr) return 0; } +static int cr50_i2c_probe(struct tpm_chip *chip, uint32_t *did_vid) +{ + int retries; + + /* + * 150 ms should be enough to synchronize with the TPM even under the + * worst nested reset request conditions. In vast majority of cases + * there would be no wait at all. + */ + printk(BIOS_INFO, "Probing TPM I2C: "); + + for (retries = 15; retries > 0; retries--) { + int rc; + + rc = cr50_i2c_read(chip, TPM_DID_VID(0), (uint8_t *)did_vid, 4); + + /* Exit once DID and VID verified */ + if (!rc && (*did_vid == CR50_DID_VID)) { + printk(BIOS_INFO, "done! DID_VID 0x%08x\n", *did_vid); + return 0; + } + + /* TPM might be resetting, let's retry in a bit. */ + mdelay(10); + printk(BIOS_INFO, "."); + } + + /* + * I2C reads failed, or the DID and VID didn't match + */ + printk(BIOS_ERR, "DID_VID 0x%08x not recognized\n", *did_vid); + return -1; +} + int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr) { struct tpm_inf_dev *tpm_dev = car_get_var_ptr(&g_tpm_dev); - uint32_t vendor; + uint32_t did_vid = 0; if (dev_addr == 0) { printk(BIOS_ERR, "%s: missing device address\n", __func__); @@ -471,6 +505,9 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr) cr50_vendor_init(chip); + if (cr50_i2c_probe(chip, &did_vid)) + return -1; + if (ENV_VERSTAGE || ENV_BOOTBLOCK) if (process_reset(chip)) return -1; @@ -478,17 +515,8 @@ int tpm_vendor_init(struct tpm_chip *chip, unsigned int bus, uint32_t dev_addr) 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) - return -1; - - if (vendor != CR50_DID_VID) { - printk(BIOS_DEBUG, "Vendor ID 0x%08x not recognized\n", vendor); - return -1; - } - printk(BIOS_DEBUG, "cr50 TPM 2.0 (i2c %u:0x%02x id 0x%x)\n", - bus, dev_addr, vendor >> 16); + bus, dev_addr, did_vid >> 16); chip->is_open = 1; return 0; |