[U-Boot] P2020 L2 cache as SRAM

DarkKhan
2011-10-19T11:53:05Z

Hi Scott,

I need your help with an issue ,i think, related to this topic.

I have P2020RDB development kit and try to boot it from nand flash using
u-boot codes.

But unfortunately, nand boot process is trapped. Once i have changed the
value of the CONFIG_SYS_INIT_L2_ADDR definition from F8F80000 to the
F7F80000, than that problem has been disappeared. Why ?! Any idea ?

Also i wonder, why this CONFIG_SYS_INIT_L2_ADDR is chosen as F8F80000 for
the L2 SRAM base adress through the u-boot codes.

Those codes can be found form those links below:

http://gitorious.org/beagleboard-validation/u-boot/blobs/f51cdaf19141151ce2b40d562a468605340f2315/arch/powerpc/cpu/mpc85xx/cpu_init_nand.c
(=> Line number 48)

http://gitorious.org/beagleboard-validation/u-boot/blobs/525f6c3add71c0fba0911d770bba5e9282be0cf2/include/configs/P1_P2_RDB.h
(=> Line number 106)

I couldn't undertand why f8f80000 address is chosen for L2 SRAM base
adress in the the u-boot P1_P2_RDB.h header file?

thnx for
your
attention.

-murat

Scott Wood-2 wrote:
>
> On Wed, 19 Jan 2011 08:50:52 +0100
> Fabian Cenedese <Cenedese@indel.ch> wrote:
>
>> At 09:07 17.01.2011 +0100, Fabian Cenedese wrote:
>> >Hi
>> >
>> >We're trying to configure the PPC P2020 cpu to use the L2 cache
>> >as SRAM so we can load the U-Boot code in there. However we
>> >stumble into problems. Sometimes the cpu goes on trap when
>> >trying to access this area. Sometimes there's no trap but we
>> >seem to access a different area. That's probably a problem with
>> >setting up a TLB/LAW.
>> >
>> >Has anybody already done this and could share some code with
>> >us?
>> >
>> >I've seen that there's a mpc85xx branch with quite some work
>> >going on. Where should we base our work on? Should we use
>> >the master or is it better to use this branch? I'm used to svn,
>> >not git, so there may be other options I don't know about yet.
>>
>> I know you're busy with patches and releasing, I just wanted
>> to ask again if anybody has already done this.
>
> Yes, it's been done. P1_P2_RDB does this when configured for NAND boot.
>
> Look for CONFIG_SYS_INIT_L2_ADDR.
>
> -Scott
>
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