On Thu, Feb 16, 2017 at 03:33:36PM +0000, Peter Huewe wrote:
> From: Alexander Steffen <alexander.stef...@infineon.com>
>
> 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.
>
> Cc: sta...@vger.kernel.org
> Fixes: aec04cbdf723 ("tpm: TPM 2.0 FIFO Interface")
>
> Signed-off-by: Alexander Steffen <alexander.stef...@infineon.com>
> Signed-off-by: Peter Huewe <peter.hu...@infineon.com>
Pushed.
/Jarkko
> ---
> drivers/char/tpm/tpm_tis_core.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index c0f296b5d413..fc0e9a2734ed 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)
> --
> 2.7.4
>
