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| author | Alexander Steffen <Alexander.Steffen@infineon.com> | 2017-02-16 15:33:36 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-25 13:44:30 (GMT) |
| commit | 5c1bd0cb49929e84bfafc2c442dfa9b54e26a4a4 (patch) | |
| tree | 3fdacf90815a7cff2887d817acd3403bf0fd024d /drivers/char | |
| parent | 3888f62943bbc77496dc919080296c3a954b56a9 (diff) | |
| download | linux-5c1bd0cb49929e84bfafc2c442dfa9b54e26a4a4.tar.xz | |
tpm_tis_core: Choose appropriate timeout for reading burstcount
commit 302a6ad7fc77146191126a1f3e2c5d724fd72416 upstream.
TIS v1.3 for TPM 1.2 and PTP for TPM 2.0 disagree about which timeout
value applies to reading a valid burstcount. It is TIMEOUT_D according to
TIS, but TIMEOUT_A according to PTP, so choose the appropriate value
depending on whether we deal with a TPM 1.2 or a TPM 2.0.
This is important since according to the PTP TIMEOUT_D is much smaller
than TIMEOUT_A. So the previous implementation could run into timeouts
with a TPM 2.0, even though the TPM was behaving perfectly fine.
During tpm2_probe TIMEOUT_D will be used even with a TPM 2.0, because
TPM_CHIP_FLAG_TPM2 is not yet set. This is fine, since the timeout values
will only be changed afterwards by tpm_get_timeouts. Until then
TIS_TIMEOUT_D_MAX applies, which is large enough.
Fixes: aec04cbdf723 ("tpm: TPM 2.0 FIFO Interface")
Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Peter Huewe <peter.huewe@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/tpm/tpm_tis_core.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index a1ce060..4d24ec3 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -160,8 +160,10 @@ static int get_burstcount(struct tpm_chip *chip) u32 value; /* wait for burstcount */ - /* which timeout value, spec has 2 answers (c & d) */ - stop = jiffies + chip->timeout_d; + if (chip->flags & TPM_CHIP_FLAG_TPM2) + stop = jiffies + chip->timeout_a; + else + stop = jiffies + chip->timeout_d; do { rc = tpm_tis_read32(priv, TPM_STS(priv->locality), &value); if (rc < 0) |