[PATCH v2 0/2] tpm_tis: fix retry exhaustion and add logging

[Jacqueline Wong <jacqwong@google.com>]

The Fix:
- Patch 1: Adds error logs to identify the specific hardware status mismatch.
- Patch 2: Stops execution immediately when retries are exhausted.

v2 changes:
- Split logging and logic into separate patches.
- Added retry count to the error message.
- Included dmesg traces below.

Testing:
Dmesg traces obtained using error injection to simulate status register mismatches.

Before:
[  130.288751] tpm tpm0: Operation Timed out
[  250.306070] tpm tpm0: Operation Timed out
[  250.310173] tpm tpm0: A TPM error (-62) occurred attempting to determine the timeouts

After:
[   10.271547] tpm tpm0: TPM_STS_DATA_EXPECT should be unset. sts = 0x00000080
...
[   10.646283] tpm tpm0: TPM_STS_DATA_EXPECT should be unset. sts = 0x00000080
[   10.653461] tpm tpm0: Exhausted 50 tpm_tis_send_data retries
[   10.659304] tpm tpm0: tpm_try_transmit: send(): error -5
[   10.665435] tpm tpm0: TPM_STS_DATA_EXPECT should be unset. sts = 0x00000080
...
[   11.037198] tpm tpm0: TPM_STS_DATA_EXPECT should be unset. sts = 0x00000080
[   11.044441] tpm tpm0: Exhausted 50 tpm_tis_send_data retries
[   11.050288] tpm tpm0: tpm_try_transmit: send(): error -5
[   11.055723] tpm tpm0: A TPM error (-5) occurred attempting to determine the timeouts

Jacqueline Wong (2):
  tpm: tpm_tis: add error logging for data transfer
  tpm: tpm_tis: stop transmit if retries are exhausted

 drivers/char/tpm/tpm_tis_core.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

-- 
2.53.0.1213.gd9a14994de-goog