[U-Boot] [PATCH 1/2 V2] arm926: Flush the data cache before disabling it.

Christian Riesch
2012-01-14T17:18:10Z

Hi Albert,

On Saturday, January 14, 2012, Albert ARIBAUD <albert.u.boot@aribaud.net>
wrote:
> Le 12/01/2012 07:29, Sughosh Ganu a ?crit :
>>
>> On Thu Jan 12, 2012 at 06:56:01AM +0100, Christian Riesch wrote:
>>>
>>> On Wednesday, January 11, 2012, Marek Vasut<marek.vasut@gmail.com>
wrote:
>>
>> <snip>
>>
>>>>> RBL executes an AIS script. Sughosh, could you please explain what
your
>>>
>>> AIS
>>>>>
>>>>> does or how you create it?
>>>>
>>>> So basically, this SPL business can be avoided and this all can be done
>>>
>>> in a
>>>>
>>>> standard way?
>>>
>>> I don't know, I never had to deal with booting from NAND. I was just
>>> wondering what Sughosh's AIS is doing that he gets these SPL problems.
>>> Christian
>>
>> I have checked my ais ini file, and it does the normal pll/ddr
>> settings. I think it is the rbl which might be turning the cache
>> ON.
>
> I do understand it is ROM code so no change can be done to it, but that a
bootloader pass control to its payload with the cache still enabled and,
worse yet, dirty, is Bad(tm).
>
> Can the AIS not be augmented with instructions to flush and disable the
cache?

I checked the AIS documentation and I don't think this can be done... AIS
has a command to write arbitrary memory regions, but not registers.
Christian