Query: ARM Cortex A9: Is invalidating L1 data cache mandatory before usage

[shiraz hashim]

Hello Russell,

On Sat, Apr 17, 2010 at 11:44 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Sat, Apr 17, 2010 at 03:26:13PM +0530, Shiraz HASHIM wrote:
>> Hello,
>>
>> I am trying to port Linux on ARM Cortex A9 based platform and what
>> I see is that if I don't invalidate the data cache before enabling
>> and using it (in arch/arm/boot/compressed/head.S) the system crashes.
>>
>> I need to do the same for second core before calling secondary_startup.
>>
>> Is it normal? Why then other platforms (cortex A9 based) are not doing
>> this. What am I missing?
>
> Yes, it's required.  See:
>
> http://www.arm.linux.org.uk/developer/booting.php

OK. So it means that the bootloader is expected to do this
invalidation or cleanup,
and for secondary cpus we can do it before calling secondary_startup.
Am I right ?

regards
Shiraz