[U-Boot] tpm TIS TPMv2.0

[Hecht, Martin (Avnet Silica)]

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. Can you tell me on what TPM did you test? For the SLB9670 the code doesn't work on my hardware. 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. On the other hand what about to use a xfer what can handle all three cases (in, out, in/out)?

> 
> Regards,
> Miquèl

Regards,
Martin