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authorAlexander Steffen <Alexander.Steffen@infineon.com>2017-08-31 20:18:57 +0300
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2017-10-18 18:28:46 +0300
commit87434f58be31a96d72b5ddbb98d53307300e0024 (patch)
tree2bdb32f534cc2abaded5f21e8763b24814961fc0 /drivers/char
parent2482b1bba5122b1d5516c909832bdd282015b8e9 (diff)
downloadlinux-87434f58be31a96d72b5ddbb98d53307300e0024.tar.xz
tpm: Use dynamic delay to wait for TPM 2.0 self test result
In order to avoid delaying the code longer than necessary while still giving the TPM enough time to execute the self tests asynchronously, start with a small delay between two polls and increase it each round. Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.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')
-rw-r--r--drivers/char/tpm/tpm2-cmd.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 8e940a530df8..2178437e541a 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -877,20 +877,17 @@ static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
static int tpm2_do_selftest(struct tpm_chip *chip)
{
int rc;
- unsigned int loops;
- unsigned int delay_msec = 100;
- unsigned long duration;
- int i;
-
- duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
+ unsigned int delay_msec = 20;
+ long duration;
- loops = jiffies_to_msecs(duration) / delay_msec;
+ duration = jiffies_to_msecs(
+ tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST));
rc = tpm2_start_selftest(chip, false);
if (rc)
return rc;
- for (i = 0; i < loops; i++) {
+ while (duration > 0) {
/* Attempt to read a PCR value */
rc = tpm2_pcr_read(chip, 0, NULL);
if (rc < 0)
@@ -900,6 +897,10 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
break;
tpm_msleep(delay_msec);
+ duration -= delay_msec;
+
+ /* wait longer the next round */
+ delay_msec *= 2;
}
return rc;