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author | Nayna Jain <nayna@linux.vnet.ibm.com> | 2018-05-07 18:07:32 +0200 |
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committer | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2018-05-14 12:48:29 +0200 |
commit | 59f5a6b07f6434efac0057dc2f303a96b871811b (patch) | |
tree | 485e5f0bf51df73ce6778bf713d8b8fb2762a5d9 /drivers/char/tpm/tpm-interface.c | |
parent | tpm_tis: verify locality released before returning from release_locality (diff) | |
download | linux-59f5a6b07f6434efac0057dc2f303a96b871811b.tar.xz linux-59f5a6b07f6434efac0057dc2f303a96b871811b.zip |
tpm: reduce poll sleep time in tpm_transmit()
tpm_try_transmit currently checks TPM status every 5 msecs between
send and recv. It does so in a loop for the maximum timeout as defined
in the TPM Interface Specification. However, the TPM may return before
5 msecs. Thus the polling interval for each iteration can be reduced,
which improves overall performance. This patch changes the polling sleep
time from 5 msecs to 1 msec.
Additionally, this patch renames TPM_POLL_SLEEP to TPM_TIMEOUT_POLL and
moves it to tpm.h as an enum value.
After this change, performance on a system[1] with a TPM 1.2 with an 8 byte
burstcount for 1000 extends improved from ~14 sec to ~10.7 sec.
[1] All tests are performed on an x86 based, locked down, single purpose
closed system. It has Infineon TPM 1.2 using LPC Bus.
Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Acked-by: Jay Freyensee <why2jjj.linux@gmail.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>
Diffstat (limited to 'drivers/char/tpm/tpm-interface.c')
-rw-r--r-- | drivers/char/tpm/tpm-interface.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 6201aab374e6..e32f6e85dc6d 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -489,7 +489,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, goto out; } - tpm_msleep(TPM_TIMEOUT); + tpm_msleep(TPM_TIMEOUT_POLL); rmb(); } while (time_before(jiffies, stop)); |