On Tue, 2021-11-02 at 17:20 +0200, amirmizi6@gmail.com wrote:

From: Amir Mizinski <redacted>

Currently, the driver polls the TPM_STS.stsValid field until TRUE; then it
reads TPM_STS register again to verify only that TPM_STS.expect field is
FALSE (i.e., it ignores TPM_STS.stsValid).
Since TPM_STS.stsValid represents the TPM_STS.expect validity, a check of
only one of these fields is wrong. Fix this condition so that both fields
are checked in the same TPM_STS register read.

Modify the signature of wait_for_tpm_stat() to tpm_tis_wait_for_stat(),
adding an additional "expected" parameter to its call.
tpm_tis_wait_for_stat() is now polling the TPM_STS with a mask and waits
for the value in "expected". This modification adds the ability to check if
certain TPM_STS bits have been cleared.
For example, use the new parameter to check in status that TPM_STS_VALID
is set and also that TPM_STS_EXPECT is zeroed. This prevents a racy
check.

Suggested-by: Benoit Houyere <redacted>
Signed-off-by: Amir Mizinski <redacted>

Thank you, this looks legit now!

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

/Jarkko