Subject: [PATCH 1/1] ARM: EXYNOS: Map SYSRAM address through DT

From: [email-masked] (Tomasz Figa)
Date: Wed, 05 Mar 2014 16:57:35 +0100

On 05.03.2014 16:36, Sachin Kamat wrote:
> On 5 March 2014 18:56, Andreas Oberritter <[email-masked]> wrote:
>> On 05.03.2014 09:23, Sachin Kamat wrote:
>>>> diff --git a/arch/arm/boot/dts/exynos4210-universal_c210.dts b/arch/arm/boot/dts/exynos4210-universal_c210.dts
>>>> index d2e3f5f5916d..3ca3fb6aa5f4 100644
>>>> --- a/arch/arm/boot/dts/exynos4210-universal_c210.dts
>>>> +++ b/arch/arm/boot/dts/exynos4210-universal_c210.dts
>>>> @@ -28,6 +28,11 @@
>>>>                  bootargs = "console=ttySAC2,115200N8 root=/dev/mmcblk0p5 rw rootwait earlyprintk panic=5 maxcpus=1";
>>>>          };
>>>>
>>>> +       sysram at 02020000 {
>>                    ^
>>>> +               compatible = "samsung,exynos4210-sysram";
>>>> +               reg = <0x02025000 0x1000>;
>>                            ^
>>>> +       };
>>>> +
>>
>> Shouldn't these two addresses match?
>
> Ideally they should. However in this case, this particular board uses
> older revision
> of the SoC which has a different register address. I did not want to
> create a compatible
> string just for this (exceptional) case alone and hence did it this
> way to override the reg. address.
> Other option was not to have the register address in the node name.

What about overriding status of sysram at 02020000 node to "disabled" and 
adding a new sysram at 02025000 node in universal C210 dts?

However, I'm still a bit concerned about using such platform and 
use-case specific compatible strings here. SYSRAM is basically a normal 
SRAM memory and usually just some specific areas of it are reserved for 
special purposes.

Best regards,
Tomasz