[PATCH v4] tpm_crb: request and relinquish locality 0

[Jerry Snitselaar]

Jarkko Sakkinen @ 2017-03-24 10:10 GMT:

> This commit adds support for requesting and relinquishing locality 0 in
> tpm_crb for the course of command transmission.
>
> In order to achieve this, two new callbacks are added to struct
> tpm_class_ops:
>
> - request_locality
> - relinquish_locality
>
> With CRB interface you first set either requestAccess or relinquish bit
> from TPM_LOC_CTRL_x register and then wait for locAssigned and
> tpmRegValidSts bits to be set in the TPM_LOC_STATE_x register.
>
> The reason why were are doing this is to make sure that the driver
> will work properly with Intel TXT that uses locality 2. There's no
> explicit guarantee that it would relinquish this locality. In more
> general sense this commit enables tpm_crb to be a well behaving
> citizen in a multi locality environment.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>

Reviewed-by: Jerry Snitselaar <jsnitsel at redhat.com>
Tested-by: Jerry Snitselaar <jsnitsel at redhat.com>

Tested on kabylake system that was hitting issues with earlier
iteration. Still don't have platform to test it dealing with
multi-locality enviroment.
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