linux-kernel - Re: [PATCH] tpm_tis: override reported C and D timeouts for Atmel 3203

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Date:   Thu, 12 Jan 2017 22:20:55 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
Cc:     Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        tpmdd-devel@...ts.sourceforge.net,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Christophe Ricard <christophe.ricard@...il.com>
Subject: Re: [PATCH] tpm_tis: override reported C and D timeouts for Atmel
 3203

On Thu, Jan 12, 2017 at 09:09:33PM +0100, Maciej S. Szmigiero wrote:
> Hi Jason,
> 
> On 12.01.2017 19:42, Jason Gunthorpe wrote:
> > On Thu, Jan 12, 2017 at 07:08:53PM +0100, Maciej S. Szmigiero wrote:
> >> Since commit 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM
> >> access") Atmel 3203 TPM on ThinkPad X61S (TPM firmware version 13.9) no
> >> longer works.
> >> It turns out the initialization proceeds fine until we get and start using
> >> chip-reported timeouts - and the chip reports C and D timeouts of zero.
> >>
> >> Since these are clearly not long enough let's add an override for them
> >> to TPM TIS default values, just as we do for Atmel 3204.
> >> A and B timeouts are set to the same values as the chip normally reports.
> >>
> >> Signed-off-by: Maciej S. Szmigiero <mail@...iej.szmigiero.name>
> > 
> >>  static const struct tis_vendor_timeout_override vendor_timeout_overrides[] = {
> >> +	/* Atmel 3203 */
> >> +	{ 0x32031114, { (10*1000), (10*1000),
> >> +			(TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
> >>  	/* Atmel 3204 */
> >>  	{ 0x32041114, { (TIS_SHORT_TIMEOUT*1000), (TIS_LONG_TIMEOUT*1000),
> >>  			(TIS_SHORT_TIMEOUT*1000), (TIS_SHORT_TIMEOUT*1000) } },
> > 
> > Can you also add a check for 0 timeouts in the core code and print a
> > FW_BUG :\
> 
> Hmm, I dug in history of tpm-interface.c and the code had actually rejected
> zero timeouts until commit 8e54caf407b98e (this is the commit that
> introduced the Atmel 3204 workaround) and let default timeout values remain
> instead (it looks like they were exactly like these in above override at
> that time).
> 
> Did Atmel 3204 report wrong but non-zero timeouts?

Wouldn't it make more sense to fix this by re-adding this fallback?

/Jarkko