ARM Linux: Where the SDRAM address and size defined

ARM Linux: Where the SDRAM address and size defined

[Woody Wu]

Hi,

In Samsung s3c24xx arch code, I cannot find where the SDRAM address and
size information was defined. Can someone give me a lead? Thanks.

-woody


-- 
Life is the only flaw in an otherwise perfect nonexistence
    -- Schopenhauer

woody
public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)
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ARM Linux: Where the SDRAM address and size defined

[priyaranjan]

Hello Woody,

>On Mon, Mar 7, 2016 at 10:55 AM, Woody Wu <narkewoody@gmail.com> wrote:

> >Hi,
>
> >In Samsung s3c24xx arch code, I cannot find where the SDRAM address and
> size information was defined. Can someone give me a lead? Thanks.
>
> I will try to answer this.

Its usual practice to have the size of RAM in bootargs in Linux kernel. And
I am not sure about the SDRAM address(It may be part of DTSI file).


> >-woody
>
>
> >--
> >Life is the only flaw in an otherwise perfect nonexistence
> >    -- Schopenhauer
>
> >woody
> >public key at http://subkeys.pgp.net:11371 (narkewoody at gmail.com)
>
>
>
> _______________________________________________
> >Kernelnewbies mailing list
> >Kernelnewbies at kernelnewbies.org
> >http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
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ARM Linux: Where the SDRAM address and size defined

[fser at code-libre.org]

On Mon, Mar 07, 2016 at 01:25:25PM +0800, Woody Wu wrote:
> Hi,

Hello,

> In Samsung s3c24xx arch code, I cannot find where the SDRAM address and
> size information was defined. Can someone give me a lead? Thanks.

ARM boards, are now defined using Device Tree (DTS for source, DTB for binary, the compiled form).
I couldn't find out for s3c24xx but, the block memory is defined as follow:

        memory {
                reg = <0x20000000 0x20000000>;
        };

(source: arch/arm/boot/dts/sama5dxcm.dtsi)

>
> -woody

--
Fran?ois

ARM Linux: Where the SDRAM address and size defined

[Woody Wu]

Sent from my iPad

> On Mar 7, 2016, at 6:04 PM, fser at code-libre.org wrote:
> 
>> On Mon, Mar 07, 2016 at 01:25:25PM +0800, Woody Wu wrote:
>> Hi,
> 
> Hello,
> 
>> In Samsung s3c24xx arch code, I cannot find where the SDRAM address and
>> size information was defined. Can someone give me a lead? Thanks.
> 
> ARM boards, are now defined using Device Tree (DTS for source, DTB for binary, the compiled form).
> I couldn't find out for s3c24xx but, the block memory is defined as follow:
> 
>        memory {
>                reg = <0x20000000 0x20000000>;
>        };
> 

What about boards that is not using DTD?  For the DTD based boards like above  I also wondering that how to define a board with two SDRAM bands, one is at 0x30000000 - 0x34000000 and another is at 0x38000000 - 0x3C000000, should I put two reg entries in the memory section of the above dtd?

> (source: arch/arm/boot/dts/sama5dxcm.dtsi)
> 
>> 
>> -woody
> 
> --
> Fran?ois
> 
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

ARM Linux: Where the SDRAM address and size defined

[Carlo Caione]

On Mon, Mar 7, 2016 at 11:04 AM,  <fser@code-libre.org> wrote:
> On Mon, Mar 07, 2016 at 01:25:25PM +0800, Woody Wu wrote:
>> Hi,
>
> Hello,
>
>> In Samsung s3c24xx arch code, I cannot find where the SDRAM address and
>> size information was defined. Can someone give me a lead? Thanks.
>
> ARM boards, are now defined using Device Tree (DTS for source, DTB for binary, the compiled form).
> I couldn't find out for s3c24xx but, the block memory is defined as follow:
>
>         memory {
>                 reg = <0x20000000 0x20000000>;
>         };
>

For the record. The memory node in the DTS is most of the time useless
/ there for documentation since the node is overwritten by the
bootloader who is in charge to initialized the DRAM.

-- 
Carlo Caione