[U-Boot] tpm TIS TPMv2.0

[Hecht, Martin (Avnet Silica)]

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. 
> 
> > For the code you wrote I'm considering to add a few lines to control
> > the CS# in that way how my xfer is doing this for the SLB9670.
> 
> Yes please, share the patch and add me in cc so I could test it with mine.
Fine, will do so soon.
> 
> > On the other hand what about to use a xfer what can handle all three
> > cases (in, out, in/out)?
> 
> As I did not implement any TPM command that needed it I did not care about
> it. Of course if there is a need for it: it should be implemented too. I
> contributed only basic support for essential commands (measured boot,
> mainly) but please feel free to enhance the code to add more features!
> 
Ok, seems we are working on the same stuff.
> Regards,
> Miquèl
Regards,
Martin