Re: [PATCH v10 2/8] tpm: tpm_tis: Fix expected bit handling and send all bytes in one shot without last byte in exception

[Jarkko Sakkinen]

On Wed, Jun 17, 2020 at 04:01:12AM +0300, Jarkko Sakkinen wrote:
> On Thu, Jun 04, 2020 at 04:47:07PM +0300, amirmizi6@xxxxxxxxx wrote:
> > From: Amir Mizinski <amirmizi6@xxxxxxxxx>
> > 
> > Detected the following incorrect implementation of the send command:
> > polling on the TPM_STS.stsValid field followed by checking the
> > TPM_STS.expect field only once. Since TPM_STS.stsValid represents the
> > TPM_STS.expect validity, both fields should be polled at the same time.
> > 
> > This fix modifies the signature of wait_for_tpm_stat(), adding an
> > additional "mask_result" parameter to its call. wait_for_tpm_stat() is now
> > polling the TPM_STS with a mask and waits for the value in mask_result.
> > The fix adds the ability to check if certain TPM_STS bits have been
> > cleared.
> > 
> > This change is also aligned to verifying the CRC on I2C TPM. The CRC
> > verification should be done after the TPM_STS.expect field is cleared
> > (TPM received all expected command bytes and set the calculated CRC value
> > in the register).
> > 
> > In addition, the send command was changed to comply with
> > TCG_DesignPrinciples_TPM2p0Driver_vp24_pubrev.pdf as follows:
> > - send all command bytes in one loop
> > - remove special handling of the last byte
> > 
> > Suggested-by: Benoit Houyere <benoit.houyere@xxxxxx>
> > Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
> 
> Just wondering how did you come up with that name since you are not
> masking anything with 'mask_result'?

Maybe just rename it as 'stat'? That would make the whole thing a lot
less confusing looking I think.

/Jarkko