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

[Kyle Evans]

On Thu, Dec 21, 2017 at 8:55 AM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> Hi Kyle,
>
> On Tue, Dec 19, 2017 at 03:05:23PM -0600, kevans91@xxxxxxx 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@xxxxxxx>
>
> 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.

Hello!

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.

[1] https://people.freebsd.org/~kevans/sunxi-sid.diff
[2] https://svnweb.freebsd.org/base/head/sys/arm/allwinner/aw_sid.c?view=markup#l56