[U-Boot] tpm TIS TPMv2.0

[Hecht, Martin (Avnet Silica)]

Hi Miquèl,
> Hi Martin (Avnet Silica),
> 
> On Mon, 18 Jun 2018 09:29:33 +0000, "Hecht, Martin (Avnet Silica)"
> <Martin.Hecht at avnet.eu> wrote:
> 
> > Hi Miquel,
> > > -----Original Message-----
> > > From: Miquel Raynal [mailto:miquel.raynal at bootlin.com]
> > > Sent: Montag, 18. Juni 2018 11:22
> > > To: Hecht, Martin (Avnet Silica) <Martin.Hecht at avnet.eu>
> > > Cc: sjg at chromium.org; u-boot at lists.denx.de; Roeder, Michael (Avnet
> > > Silica) <Michael.Roeder at avnet.eu>
> > > Subject: Re: [U-Boot] tpm TIS TPMv2.0
> > >
> > > Hi Martin,
> > >
> > > On Mon, 18 Jun 2018 09:13:36 +0000, "Hecht, Martin (Avnet Silica)"
> > > <Martin.Hecht at avnet.eu> wrote:
> > >
> > > > Hi Miquèl,
> > > >
> > > > > -----Original Message-----
> > > > > From: Miquel Raynal [mailto:miquel.raynal at bootlin.com]
> > > > > Sent: Montag, 18. Juni 2018 10:43
> > > > > To: Hecht, Martin (Avnet Silica) <Martin.Hecht at avnet.eu>
> > > > > Cc: sjg at chromium.org; u-boot at lists.denx.de
> > > > > Subject: Re: [U-Boot] tpm TIS TPMv2.0
> > > > >
> > > > > Hi Martin,
> > > > >
> > > > > On Mon, 18 Jun 2018 08:20:20 +0000, "Hecht, Martin (Avnet Silica)"
> > > > > <Martin.Hecht at avnet.eu> wrote:
> > > > >
> > > > > > Hi Miquel,
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Miquel Raynal [mailto:miquel.raynal at bootlin.com]
> > > > > > > Sent: Montag, 18. Juni 2018 10:05
> > > > > > > To: Hecht, Martin (Avnet Silica) <Martin.Hecht at avnet.eu>
> > > > > > > Cc: sjg at chromium.org; u-boot at lists.denx.de
> > > > > > > Subject: Re: [U-Boot] tpm TIS TPMv2.0
> > > > > > >
> > > > > > > Hi Martin,
> > > > > > >
> > > > > > > On Fri, 15 Jun 2018 13:34:07 +0000, "Hecht, Martin (Avnet Silica)"
> > > > > > > <Martin.Hecht at avnet.eu> wrote:
> > > > > > >
> > > > > > > > Hi Miquel, Simon,
> > > > > > > >
> > > > > > > > Is there any specific reason why the new tpm2_tis_spi_xfer
> > > > > > > > doesn't
> > > > > > > support full duplex? It seems we did some work in parallel
> > > > > > > but you sent the patches earlier. Is that codes tested
> > > > > > > against an existing TPM v2? I have a working implementation
> > > > > > > what runs on
> > > > > > > SLB9670 including
> > > > > full duplex.
> > > > > > >
> > > > > > > What do you mean exactly?
> > > > > > >
> > > > > > > I don't think the TPM2 protocol makes real use of
> > > > > > > full-duplex unless for the wait state between the host
> > > > > > > command and the actual
> > > xfer.
> > > > > >
> > > > > > You are right, TIS 1.3 FIFO doesn’t use full duplex in
> > > > > > physical level. What I
> > > > > mean is that the driver you just wrote doesn't use the xfer
> > > > > function in that way that you can specify in and out parameters at
> same time.
> > > > > I did this in my implementation what gave me an easy chance to
> > > > > control
> > > the CS# of the TPM.
> > > > >
> > > > > Do you need this CS# handling for more advanced features? Same
> > > > > question for the in/out xfers?
> > > > >
> > > > > > Can you tell me on what TPM did you test? For the SLB9670 the
> > > > > > code doesn't work on my hardware.
> > > > >
> > > > > I tested with a ST33TPHF20 SPI TPM.
> > > > >
> > > > > I'm surprised it did not work with an SLB9670, I don't see
> > > > > anything in the spec explaining this CS# specificity.
> > > >
> > > > The CS# may controls an internal state machine and the SLB9670
> > > > uses that
> > > signal.
> > >
> > > Ok, can you explain what should be done (and where/when) to make it
> > > work with the SLB9670?
> > Please let me come back with my proposal soon. I have already the tpm
> > running with my little different driver. There is another patch
> > required for my SoC to setup the SPI correctly.
> 
> ok
> 
> > Nevertheless one question: Why did you define another dts binding
> > instead of using that one what is already available on the Linux
> > kernel? There is "tcg,tpm_tis-spi"  already defined.
> 
> I did not know this one, actually I mostly worked on U-Boot.
> 
> However, this compatible is misleading as it does not make any difference
> between v1.x and v2.0 specification.

But on the other hand it would give us a chance to determine the version at 
runtime what could be beneficial for firmware updates. But this is a special case.

> Regards,
> Miquèl

Regards,
Martin