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-rw-r--r--src/drivers/i2c/tpm/cr50.c148
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);
}