tpm: reduce tpm polling delay in tpm_tis_core
authorNayna Jain <nayna@linux.vnet.ibm.com>
Tue, 17 Oct 2017 20:32:31 +0000 (16:32 -0400)
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Mon, 8 Jan 2018 10:58:33 +0000 (12:58 +0200)
commitcf151a9a44d52a63332e8e926234574fe5a5d784
treecbc70f536e73009213eaec0915cbb1510e464f7c
parent87cdfdd19aefcf639507ce96ae8f403539a8ba29
tpm: reduce tpm polling delay in tpm_tis_core

The existing wait_for_tpm_stat() polls for the chip status after
5msec sleep. As per TCG ddwg input, it is expected that tpm might
return status in few usec. So, reducing the delay in polling to
1msec.
Similarly, get_burstcount() function sleeps for 5msec before
retrying for next query to burstcount in a loop. If it takes
lesser time for TPM to return, this 5msec delay is longer than
necessary.

After this change, performance on a TPM 1.2 with an 8 byte
burstcount for 1000 extends improved from ~14sec to ~9sec.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
drivers/char/tpm/tpm_tis_core.c