Re: [PATCH 2/2 v2] tpm_tis: override durations for STM tpm with firmware

From: Jerry Snitselaar
Date: Thu Aug 29 2019 - 16:25:36 EST

On Thu Aug 29 19, Jarkko Sakkinen wrote:
On Tue, Aug 27, 2019 at 05:46:21PM -0700, Jerry Snitselaar wrote:
There was revealed a bug in the STM TPM chipset used in Dell R415s.
Bug is observed so far only on chipset firmware
(1.2 TPM, device-id 0x0, rev-id 78). After some number of
operations chipset hangs and stays in inconsistent state:

tpm_tis 00:09: Operation Timed out
tpm_tis 00:09: tpm_transmit: tpm_send: error -5

Durations returned by the chip are the same like on other
firmware revisions but apparently with specifically fw
durations should be reset to 2 minutes to enable tpm chip work
properly. No working way of updating firmware was found.

This patch adds implementation of ->update_durations method
that matches only STM devices with specific firmware version.

Cc: Peter Huewe <peterhuewe@xxxxxx>
Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Signed-off-by: Alexey Klimov <aklimov@xxxxxxxxxx>
Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
v2: Make suggested changes from Jarkko
- change struct field name to durations from durs
- formatting cleanups
- turn into void function like update_timeouts and
use chip->duration_adjusted to track whether adjustment occurred.

The code repetition looks horrible so I wrote a patch that should help:

Read the remar that prepends the diffstat.


LGTM, and testing it on a 1.2 tpm system here worked fine. You can add my
Reviewed-by and Tested-by.

I have reworked this 2/2 patch to make use of these new structs and
pull the tpm1_getcap calls out of the for loop. So I will submit a v3
to go on top of your patch.