linux-imx

tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated

For TPM 1.2 chips the system setup utility allows to set the TPM device in
one of the following states:

  * Active: Security chip is functional
  * Inactive: Security chip is visible, but is not functional
  * Disabled: Security chip is hidden and is not functional

When choosing the "Inactive" state, the TPM 1.2 device is enumerated and
registered, but sending TPM commands fail with either TPM_DEACTIVATED or
TPM_DISABLED depending if the firmware deactivated or disabled the TPM.

Since these TPM 1.2 error codes don't have special treatment, inactivating
the TPM leads to a very noisy kernel log buffer that shows messages like
the following:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  tpm tpm0: TPM is disabled/deactivated (0x6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  ima: No TPM chip found, activating TPM-bypass! (rc=6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random

Let's just suppress error log messages for the TPM_{DEACTIVATED,DISABLED}
return codes, since this is expected when the TPM 1.2 is set to Inactive.

In that case the kernel log is cleaner and less confusing for users, i.e:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: TPM is disabled/deactivated (0x6)
  ima: No TPM chip found, activating TPM-bypass! (rc=6)

Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>