From: Nayna Jain Date: Mon, 7 May 2018 16:07:32 +0000 (-0400) Subject: tpm: reduce poll sleep time in tpm_transmit() X-Git-Tag: v4.18-rc1~99^2~1^2~4 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=59f5a6b07f6434efac0057dc2f303a96b871811b;p=linux.git 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 Acked-by: Jay Freyensee Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- 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)); diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index af3bb87d3ea1..baa066997372 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 d547cd309dbd..7bfdec66be44 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 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, } } 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; }