tpm_crb: request and relinquish locality 0

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@linux.intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Tested-by: Jerry Snitselaar <jsnitsel@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index aade6995f310..a321bd57f3e9 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -231,6 +231,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 		goto out;
 	}
 
+	chip->locality = -1;
 	return chip;
 
 out: