Re: [PATCH v2] ARM: dts: sunxi: Add sid for a83t

From: Kyle Evans <kevans91-OYTqUY/oFF8@public.gmane.org>
To: Maxime Ripard
	<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Cc: Srinivas Kandagatla
	<srinivas.kandagatla-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	Russell King <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
Subject: Re: [PATCH v2] ARM: dts: sunxi: Add sid for a83t
Date: Thu, 21 Dec 2017 09:30:56 -0600	[thread overview]
Message-ID: <CACNAnaF23H-S7-d3F1_GQeJFJh6RwA0=dX1nfM4SM3ikB2TE+A@mail.gmail.com> (raw)
In-Reply-To: <20171221152630.2vf57x5o2yi5sv3n-ZC1Zs529Oq4@public.gmane.org>

On Thu, Dec 21, 2017 at 9:26 AM, Maxime Ripard
<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 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-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:
>> > Hi Kyle,
>> >
>> > On Tue, Dec 19, 2017 at 03:05:23PM -0600, kevans91-OYTqUY/oFF8@public.gmane.org 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-OYTqUY/oFF8@public.gmane.org>
>> >
>> > 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. 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.

Yeah, we've had this exact binding in our own copy of DTS up until a
recent point when we flipped the switch to pulling DT from Mainline
Linux and trying to upstream changes instead of having a bunch of
local modifications in our tree.

> Chen-Yu, what do you think?
>
> Thanks!
> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com
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