linux-kernel - Re: [PATCH v2 2/2] tpm: tis: add support for MMIO TPM on SynQuacer

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Message-ID: <a3720028f46885e806f201b6fa6ea6f8ef6b0d44.camel@linux.intel.com>
Date:   Thu, 30 Jan 2020 10:37:25 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:     Ard Biesheuvel <ardb@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>,
        Devicetree List <devicetree@...r.kernel.org>,
        linux-integrity <linux-integrity@...r.kernel.org>,
        Peter Hüwe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>
Subject: Re: [PATCH v2 2/2] tpm: tis: add support for MMIO TPM on SynQuacer

On Thu, 2020-01-23 at 13:29 +0100, Ard Biesheuvel wrote:
> On Thu, 23 Jan 2020 at 13:27, Jarkko Sakkinen
> <jarkko.sakkinen@...ux.intel.com> wrote:
> > On Tue, 2020-01-14 at 15:16 +0100, Ard Biesheuvel wrote:
> > > When fitted, the SynQuacer platform exposes its SPI TPM via a MMIO
> > > window that is backed by the SPI command sequencer in the SPI bus
> > > controller. This arrangement has the limitation that only byte size
> > > accesses are supported, and so we'll need to provide a separate set
> > > of read and write accessors that take this into account.
> > 
> > What is SynQuacer platform?
> > 
> 
> It is an arm64 SoC manufactured by Socionext.
> 
> > I'm also missing a resolution why tpm_tis.c is extended to handle both
> > and not add tpm_tis_something.c instead. It does not follow the pattern
> > we have in place (e.g. look up tpm_tis_spi.c).
> > 
> 
> We could easily do that instead, if preferred. It's just that it would
> duplicate a bit of code.

I'm fine with that. Overally I think it is cleaner flow.

/Jarkko