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| author | Nayna Jain <nayna@linux.vnet.ibm.com> | 2018-05-07 12:07:32 -0400 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2018-05-14 13:48:29 +0300 |
| commit | 59f5a6b07f6434efac0057dc2f303a96b871811b (patch) | |
| tree | 485e5f0bf51df73ce6778bf713d8b8fb2762a5d9 /drivers | |
| parent | 33bafe90824bc9584fad535410bebc1fbe382fdf (diff) | |
| download | linux-0-day-59f5a6b07f6434efac0057dc2f303a96b871811b.tar.gz linux-0-day-59f5a6b07f6434efac0057dc2f303a96b871811b.tar.xz | |
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')
| -rw-r--r-- | drivers/char/tpm/tpm-interface.c | 2 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm.h | 3 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm_tis_core.c | 10 |
3 files changed, 5 insertions, 10 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 6201aab374e6a..e32f6e85dc6d0 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)); diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index af3bb87d3ea1e..baa0669973726 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -53,7 +53,8 @@ enum tpm_const { enum tpm_timeout { TPM_TIMEOUT = 5, /* msecs */ TPM_TIMEOUT_RETRY = 100, /* msecs */ - TPM_TIMEOUT_RANGE_US = 300 /* usecs */ + TPM_TIMEOUT_RANGE_US = 300, /* usecs */ + TPM_TIMEOUT_POLL = 1 /* msecs */ }; /* TPM addresses */ diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index d547cd309dbdf..7bfdec66be447 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -31,12 +31,6 @@ #include "tpm.h" #include "tpm_tis_core.h" -/* This is a polling delay to check for status and burstcount. - * As per ddwg input, expectation is that status check and burstcount - * check should return within few usecs. - */ -#define TPM_POLL_SLEEP 1 /* msec */ - static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value); static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, @@ -90,7 +84,7 @@ again: } } else { do { - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); status = chip->ops->status(chip); if ((status & mask) == mask) return 0; @@ -279,7 +273,7 @@ static int get_burstcount(struct tpm_chip *chip) burstcnt = (value >> 8) & 0xFFFF; if (burstcnt) return burstcnt; - tpm_msleep(TPM_POLL_SLEEP); + tpm_msleep(TPM_TIMEOUT_POLL); } while (time_before(jiffies, stop)); return -EBUSY; } |