After further discussions with the TCG Device Driver working group (ddwg), the following changes were made: * Check for burstcount at least once to confirm the TPM is ready to accept the data. Similarly, query for the TPM Expect status as sanity check at the end. * Make the sleep for status check in the loop less than 5msec. * Make the sleep in the loop while querying for burstcount less than 5msec. Below is the list of patches along with the performance improvements seen with a TPM 1.2 with an 8 byte burstcount for 1000 extends: Patch |Improvement(time in sec) tpm: ignore burstcount to improve tpm_tis | ~41 - ~14 send() performance. tpm: reduce polling delay in tpm_tis_core | ~14 - ~9 tpm: modify tpm_msleep() function to have | ~9 - ~8 max range Changelog v4: * Include Jarkko's feedback on merging two patches reducing sleep time during polling to TPM. * Include Jarkko's feedback to clean up the burstcount change patch and add comment for new #define. Changelog v3: * Include Jarkko's feedback to move wait_for_tpm_stat() from tpm-interface.c to respective driver files tpm_tis_core.c and xen-tpmfront.c. * Remove use of module parameter ignore_burst_count and is now alwaysed ignored in tpm tis send() operation. * Reduce sleep() time during polling in wait_for_tpm_stat() from 5msec to 1msec for both recv() and send() operation. Version 2 of the patches had it only for send() operation. Changelog v2: * Add module parameter to handle ignoring of burst count during tpm tis send() operation. * Add improvements over sleep time to reduce delays. Nayna Jain (4): tpm: move wait_for_tpm_stat() to respective driver files tpm: ignore burstcount to improve tpm_tis send() performance tpm: reduce tpm polling delay in tpm_tis_core tpm: use tpm_msleep() value as max delay drivers/char/tpm/tpm-interface.c | 60 --------------------- drivers/char/tpm/tpm.h | 6 +-- drivers/char/tpm/tpm_tis_core.c | 110 +++++++++++++++++++++++++++++---------- drivers/char/tpm/xen-tpmfront.c | 60 +++++++++++++++++++++ 4 files changed, 144 insertions(+), 92 deletions(-) -- 2.13.3
