[rtems commit] Shared MMU initialization for ARM BSPs and RaspberryPi MMU support

[Hesham Moustafa]

On Fri, Oct 4, 2013 at 9:50 AM, Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> On 2013-10-03 14:49, Gedare Bloom wrote:
>
>> @@ -87,9 +90,9 @@ arm_cp15_start_setup_**translation_table_and_enable_**
>> mmu_and_cache(
>>     arm_cp15_set_domain_access_**control(dac);
>>     arm_cp15_set_translation_**table_base(ttb);
>>
>> -  /* Initialize translation table with invalid entries */
>> +  /* Initialize translation table with fixed-map read-write entries */
>>     for (i = 0; i < ARM_MMU_TRANSLATION_TABLE_**ENTRY_COUNT; ++i) {
>> -    ttb [i] = 0;
>> +    ttb [i] = (i << ARM_MMU_SECT_BASE_SHIFT) | ARMV7_MMU_DATA_READ_WRITE;
>>     }
>>
>
> What is the reason for this change?  I don't think that unconditional
> read-write access is a good idea.
>
> I made this change when I was trying to get RaspberryPi MMU initialization
to work. Also I thought
the default behavior for RTEMS is the unprotected mode, and the new
protection (limitation) attributes
are new and should be applied when needed (by configuration table at
startup or dynamically).

> --
> Sebastian Huber, embedded brains GmbH
>
> Address : Dornierstr. 4, D-82178 Puchheim, Germany
> Phone   : +49 89 189 47 41-16
> Fax     : +49 89 189 47 41-09
> E-Mail  : sebastian.huber at embedded-**brains.de<sebastian.huber at embedded-brains.de>
> PGP     : Public key available on request.
>
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>
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