Hi Miquèl,
-----Original Message----- From: Miquel Raynal [mailto:miquel.raynal@bootlin.com] Sent: Montag, 18. Juni 2018 10:43 To: Hecht, Martin (Avnet Silica) Martin.Hecht@avnet.eu Cc: sjg@chromium.org; u-boot@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@avnet.eu wrote:
Hi Miquel,
-----Original Message----- From: Miquel Raynal [mailto:miquel.raynal@bootlin.com] Sent: Montag, 18. Juni 2018 10:05 To: Hecht, Martin (Avnet Silica) Martin.Hecht@avnet.eu Cc: sjg@chromium.org; u-boot@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@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