tpm: replace msleep() with usleep_range() in TPM 1.2/2.0 generic drivers
authorHamza Attak <hamza@hpe.com>
Mon, 14 Aug 2017 18:09:16 +0000 (19:09 +0100)
committerJames Morris <james.l.morris@oracle.com>
Sun, 24 Sep 2017 04:51:00 +0000 (21:51 -0700)
commit9f3fc7bcddcb51234e23494531f93ab60475e1c3
treef788e5570ade80f9cb8661330f6f9ff2f2e46e0a
parent5d0e4d78149b9745ea34848e950e734f7db3b95f
tpm: replace msleep() with  usleep_range() in TPM 1.2/2.0 generic drivers

The patch simply replaces all msleep function calls with usleep_range calls
in the generic drivers.

Tested with an Infineon TPM 1.2, using the generic tpm-tis module, for a
thousand PCR extends, we see results going from 1m57s unpatched to 40s
with the new patch. We obtain similar results when using the original and
patched tpm_infineon driver, which is also part of the patch.
Similarly with a STM TPM 2.0, using the CRB driver, it takes about 20ms per
extend unpatched and around 7ms with the new patch.

Note that the PCR consistency is untouched with this patch, each TPM has
been tested with 10 million extends and the aggregated PCR value is
continuously verified to be correct.

As an extension of this work, this could potentially and easily be applied
to other vendor's drivers. Still, these changes are not included in the
proposed patch as they are untested.

Signed-off-by: Hamza Attak <hamza@hpe.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>
Signed-off-by: James Morris <james.l.morris@oracle.com>
drivers/char/tpm/tpm-interface.c
drivers/char/tpm/tpm.h
drivers/char/tpm/tpm2-cmd.c
drivers/char/tpm/tpm_infineon.c
drivers/char/tpm/tpm_tis_core.c