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tpm: Use dynamic delay to wait for TPM 2.0 self test result

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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>
This commit is contained in:
Alexander Steffen 2017-08-31 19:18:57 +02:00 committed by Jarkko Sakkinen
parent 2482b1bba5
commit 87434f58be
1 changed files with 9 additions and 8 deletions
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17
drivers/char/tpm/tpm2-cmd.c
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@ -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;
unsigned int delay_msec = 20;
long duration;
duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
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;