tpm_tis: Introduce intermediate layer for TPM access
authorChristophe Ricard <christophe.ricard@gmail.com>
Wed, 18 May 2016 22:35:49 +0000 (00:35 +0200)
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Sat, 25 Jun 2016 14:26:35 +0000 (17:26 +0300)
commit1107d065fdf136f0c1af287fc9183a0139bd6ae6
tree93eacbf2192ccd86b14d0d62d25a667a025cf33a
parent57dacc2b4ce5350db3046721dad3d88c3b451aa2
tpm_tis: Introduce intermediate layer for TPM access

This splits tpm_tis in a high-level protocol part and a low-level interface
for the actual TPM communication. The low-level interface can then be
implemented by additional drivers to provide access to TPMs using other
mechanisms, for example native I2C or SPI transfers, while still reusing
the same TIS protocol implementation.

Though the ioread/iowrite calls cannot fail, other implementations of this
interface might want to return error codes if their communication fails.

This follows the usual pattern of negative values representing errors and
zero representing success. Positive values are not used (yet).

Errors are passed back to the caller if possible. If the interface of a
function does not allow that, it tries to do the most sensible thing it
can, but this might also mean ignoring the error in this instance.

This commit is based on the initial work by Peter Huewe.

Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
drivers/char/tpm/tpm_tis.c
drivers/char/tpm/tpm_tis_core.h