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Date: Thu, 21 Dec 2017 19:09:03 +0100
From: Emmanuel Vadot <manu@bidouilliste.com>
To: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Kyle Evans <kevans91@ksu.edu>, Mark Rutland <mark.rutland@arm.com>,
        devicetree@vger.kernel.org, linux-sunxi@googlegroups.com,
        Russell King <linux@armlinux.org.uk>, linux-kernel@vger.kernel.org,
        Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] ARM: dts: sunxi: Add sid for a83t
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 Hi Maxime,

On Thu, 21 Dec 2017 16:26:30 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> Hi,
> 
> On Thu, Dec 21, 2017 at 09:19:24AM -0600, Kyle Evans wrote:
> > On Thu, Dec 21, 2017 at 8:55 AM, Maxime Ripard
> > <maxime.ripard@free-electrons.com> wrote:
> > > Hi Kyle,
> > >
> > > On Tue, Dec 19, 2017 at 03:05:23PM -0600, kevans91@ksu.edu wrote:
> > >> Allwinner a83t has a 1 KB sid block with efuse for security rootkey and
> > >> thermal calibration data, add node to describe it.
> > >>
> > >> a83t-sid is not currently supported by nvmem/sunxi-sid, but it is
> > >> supported in an external driver for FreeBSD.
> > >>
> > >> Signed-off-by: Kyle Evans <kevans91@ksu.edu>
> > >
> > > The patch looks fine in itself, but we've had a number of issues with
> > > the register layout (and access patterns) in the past, so I'd rather
> > > have something that works in Linux too if possible.
> > 
> > I have a patch that I think should make it work fine on Linux [1], but
> > I'm afraid I have little to no capability to test it myself and so I
> > did not add it as well.
> > 
> > I do know that the rootkey is offset 0x200 into the given space [2],
> > as is the case with the H3, and that the readout quirk is not needed.
> > I wasn't 100% sure that the a83t has 2Kbit worth of efuse space as the
> > H3, but I do know that thermal data can be found at 0x34 and 0x38 in
> > this space.
> 
> Then maybe we should leave it aside until someone takes some time on
> the A83t. 

 Take some time on the Linux driver and do not apply this patch for
now you mean ?

 Cheers,

> The good news is that the binding itself looks fine, so as
> far as FreeBSD goes, there shouldn't be anything preventing you from
> using it I guess.
>
> Chen-Yu, what do you think?
> 
> Thanks!
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

-- 
Emmanuel Vadot <manu@bidouilliste.com>