[U-Boot] [PATCH 2/4][v2] powerpc/85xx:Fix MSR[DE] bit in MSR to support debugger

[Scott Wood]

On 04/25/2012 01:55 PM, Joakim Tjernlund wrote:
> 
> Scott Wood <scottwood at freescale.com> wrote on 2012/04/25 20:43:22:
>>
>> On 04/25/2012 05:57 AM, Joakim Tjernlund wrote:
>>>>
>>>> Debugging of e500 and e500v1 processer requires MSR[DE] bit to be set always.
>>>> Where MSR = Machine State register
>>>>
>>>> Make sure of MSR[DE] bit is set uniformaly across the different execution
>>>> address space i.e. AS0 and AS1.
>>>
>>> Hi
>>>
>>> We are trying to bring up our custom P2010 RDB based board. boot is NOR
>>> based and we cannot get past the rfi below.
>>>    lis   r6,MSR_IS|MSR_DS at h
>>>    ori   r6,r6,MSR_IS|MSR_DS at l
>>>    lis   r7,switch_as at h
>>>    ori   r7,r7,switch_as at l
>>>
>>>    mtspr   SPRN_SRR0,r7
>>>    mtspr   SPRN_SRR1,r6
>>>    rfi
>>>
>>> switch_as:
>>>
>>> We end up with a TLB exception no matter what we do, even after applying this patch.
>>
>> Did you apply the entire patchset, and define CONFIG_SYS_PPC_E500_DEBUG_TLB?
> 
> No, but this code is executed before any of the other parts of the patch. Anyhow, I just
> found the problem(really obvious once I found it).
> During bring up we had to load uboot in the middle of the flash instead of
> the end because we have a flash burn problem in the end of the flash that we do not
> understand yet. We think it may be related to DDR3 being misconfigured by the emulator(BDI3000).
> I do not understand why this emulator can not use the L2SRAM instead? Is there something
> magic behind the L2SRAM so it is impossible to use it as a work area for
> flash burning?

I don't know of any reason L2SRAM couldn't be used for this.  My guess
is they just don't want to have to support more than one way of creating
RAM.

-Scott