From 8c916ec8346182b6b2d085d4663be556c376f414 Mon Sep 17 00:00:00 2001 From: Sourabh Banerjee Date: Tue, 20 Jan 2015 15:18:40 +0530 Subject: tpm: wait for valid bit to be set in TPM access register before using tpm As per the TCG PC Client TPM Interface Specification v1.2, bit 7 of the access register (tmpRegValiSts bit) stays "0" until the TPM has complete through self test and initialization. This bit is set "1" to indicate that the other bits in the register are valid. BRANCH=chromeos-2013.04 BUG=chrome-os-partner:35328 TEST=Booted up storm p0.2 and whirwind sp3. Verified TPM chip is detected and reported in coreboot logs. Change-Id: I1049139fc155bfd2e1f29e3b8a7b9d2da6360857 Signed-off-by: Stefan Reinauer Original-Commit-Id: 006fc93c6308d6f3fa220f00708708aa62cc676c Original-Change-Id: I9df3388ee1ef6e4a9d200d99aea1838963747ecf Original-Signed-off-by: Sourabh Banerjee Original-Reviewed-on: https://chromium-review.googlesource.com/242222 Original-Reviewed-by: Vadim Bendebury Original-Commit-Queue: Vadim Bendebury Reviewed-on: http://review.coreboot.org/9567 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/drivers/i2c/tpm/tis.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) (limited to 'src/drivers/i2c/tpm') diff --git a/src/drivers/i2c/tpm/tis.c b/src/drivers/i2c/tpm/tis.c index 696634d9d7..d9a7651008 100644 --- a/src/drivers/i2c/tpm/tis.c +++ b/src/drivers/i2c/tpm/tis.c @@ -29,6 +29,7 @@ #include #include #include "tpm.h" +#include #include @@ -37,6 +38,7 @@ struct tpm_chip g_chip; #define TPM_CMD_COUNT_BYTE 2 #define TPM_CMD_ORDINAL_BYTE 6 +#define TPM_VALID_STATUS (1 << 7) int tis_open(void) { @@ -74,12 +76,33 @@ int tis_init(void) { int bus = CONFIG_DRIVER_TPM_I2C_BUS; int chip = CONFIG_DRIVER_TPM_I2C_ADDR; + struct stopwatch sw; + uint8_t buf = 0; + int ret; + long sw_run_duration = 750; /* - * Probe TPM twice; the first probing might fail because TPM is asleep, - * and the probing can wake up TPM. + * 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. */ - if (i2c_writeb(bus, chip, 0, 0) && i2c_writeb(bus, chip, 0, 0)) + stopwatch_init_msecs_expire(&sw, sw_run_duration); + do { + ret = i2c_readb(bus, chip, 0, &buf); + if (!ret && (buf & TPM_VALID_STATUS)) { + 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_VALID_STATUS) ? "set" : "clear", + (buf & TPM_VALID_STATUS) >> 7, sw_run_duration); + + /* + * Claim failure if the ValidSts (bit 7) is clear. + */ + if (!(buf & TPM_VALID_STATUS)) return -1; return 0; -- cgit v1.2.3