[ECOS] Redboot SDRAM Virtual Memory Mapping

[ECOS] Redboot SDRAM Virtual Memory Mapping

[tejas pawaskar]

Greetings,

I am using Intel' Xscale PXA270 processor and my SDRAM
(32-bit,104 MHz) 64MB is interfaced to BANK0 having
the physical address 0xA0000000.

In the hal_mmu_init function, the SDRAM is mapped to
virtual address 0x000 using the X_ARM_MMU_SECTION
macro as CACHED. It works fine.

But if I change the virtual address to 0x800 or any
other address other than the 0x000 the redboot does
not boots and halts at early stage after the LED 7
instruction.

Is it that the SDRAM cannot be mapped to any other
address except 0x00000000 in Redboot?

I require the SDRAM to be mapped to 0x80000000, since
I want to boot wince image.

Regards,
Tejas Pawaskar 


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Re: [ECOS] Redboot SDRAM Virtual Memory Mapping

[Andrew Lunn]

On Wed, May 02, 2007 at 07:46:43AM +0100, tejas pawaskar wrote:
> Greetings,
> 
> I am using Intel' Xscale PXA270 processor and my SDRAM
> (32-bit,104 MHz) 64MB is interfaced to BANK0 having
> the physical address 0xA0000000.
> 
> In the hal_mmu_init function, the SDRAM is mapped to
> virtual address 0x000 using the X_ARM_MMU_SECTION
> macro as CACHED. It works fine.
> 
> But if I change the virtual address to 0x800 or any
> other address other than the 0x000 the redboot does
> not boots and halts at early stage after the LED 7
> instruction.
> 
> Is it that the SDRAM cannot be mapped to any other
> address except 0x00000000 in Redboot?
> 
> I require the SDRAM to be mapped to 0x80000000, since
> I want to boot wince image.

ARM processors have there interrupt vectors at 0x00 - 0x20. So you
need RAM there in order to be able to change the interrupts at run
time. Hence the mapping to 0x0.

Can you setup two mappings? Have the memory mapped at both 0x0 and
0x80000000?

        Andrew

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