[v3,0/4] Recovery from data transfer errors for tpm_tis

Message

Alexander Steffen June 13, 2023, 6:02 p.m. UTC

Data transfer to/from hardware TPM devices is not always fully reliable.
The existing driver code contains already many checks to detect
corrupted data (e.g. unexpected register values, CRC failures, etc.) and
usually returns EIO in such cases. This series adds automatic retries to
the command/response transmission in tpm_tis_send/tpm_tis_recv, so that
occasional communication errors do not cause the command execution to
fail and the perceived reliability of the TPM device is increased.

v3:
* Rename tpm_tis_recv* functions
* Other small cleanups that were suggested in comments
v2:
* Remove Change-Ids accidentially left in commit messages

Alexander Steffen (4):
  tpm_tis: Explicitly check for error code
  tpm_tis: Move CRC check to generic send routine
  tpm_tis: Use responseRetry to recover from data transfer errors
  tpm_tis: Resend command to recover from data transfer errors

 drivers/char/tpm/tpm_tis_core.c | 69 ++++++++++++++++++++++++---------
 drivers/char/tpm/tpm_tis_core.h |  1 +
 2 files changed, 52 insertions(+), 18 deletions(-)