[SRU][N][PATCH 0/2] TPM timeouts occur on some Infineon TPMs

[Ivan Hu]

BugLink: https://bugs.launchpad.net/bugs/2137528

[Impact]
Certain Infineon TPM devices may experience timeout issues during the boot
process. This manifests as a communication failure between the kernel driver
and the TPM hardware.

The issue manifests as a communication failure between the kernel driver and
the TPM hardware during the boot process. The kernel logs the following error:
tpm tpm0: tpm_try_transmit: send(): error -62
or
tpm tpm0: Operation Timed out

When this occurs, the TPM becomes unresponsive. Any critical system services o
 boot processes that depend on the TPM will fail, leading to a boot failure or
indefinite wait state.

[Fix]
The issue is resolved by the following 4 commits
1. de9e33df7762 ("tpm, tpm_tis: Workaround failed command reception on Infineon
   devices") -- already SRUed https://bugs.launchpad.net/bugs/2128722
2. 2f661f71fda1 ("tpm: tis: Double the timeout B to 4s") -- already SRUed 
   https://bugs.launchpad.net/bugs/2130344
3. 980a573621ea ("tpm: Make chip->{status,cancel,req_canceled} opt")
4. d4640c394f23 ("tpm: Check for completion after timeout")

[Test Plan]
Run automated reboot loops on an affected Infineon device with the patched
kernel(kernel snap better). Grep logs to ensure
tpm_try_transmit: send(): error -62 or tpm tpm0: Operation Timed out
no longer appears.

[Where problems could occur]
Low. The patches add a status verification for checking completion only in
cases where the TPM seems to be unresponsive.

Jarkko Sakkinen (2):
  tpm: Make chip->{status,cancel,req_canceled} opt
  tpm: Check for completion after timeout

 drivers/char/tpm/tpm-interface.c | 47 ++++++++++++++++++++++++++++----
 drivers/char/tpm/tpm_ftpm_tee.c  | 20 --------------
 2 files changed, 42 insertions(+), 25 deletions(-)

-- 
2.43.0