[U-Boot] write to mcBsp address space

[Albert ARIBAUD]

Le 15/02/2011 09:21, Ran a écrit :
> Albert ARIBAUD<albert.aribaud<at>  free.fr>  writes:
>
>>
>> Hi Ran,
>>
>> Le 15/02/2011 07:35, Ran Shalit a écrit :
>>> Hello,
>>>
>>> I'm working on OMAPL138 EVM board, with the U-BOOT.
>>> I'm trying to access and write into the register (which have write bits),
>>> but I always read 0 in all the map space of the mcBSP0 and mcBSP1.
>>> (0x01d10000 - 0x1d10800, 0x01d11000 - 0x1d11800).
>>> I wonder what I missed here. any ideas are welcomed.
>>
>> Many SoCs have "base address registers" that allow remapping internal or
>> peripheral registers anywhere in the address space, which means the
>> actual address you're trying to get at might not be the right one. Did
>> you check the BAR(s) and make sure the mcBsp address you're targetting
>> is the right one for your board?
>>
>>> Thank you very much,
>>>
>>> Ran
>>
>> Amicalement,
>
> Hello Albert,
>
> Thank you very much for your reply.
> I've checked the datasheet but I see no reference to base address registers
> for the mcBSP.
>
> mcBSP: http://www.ti.com/litv/pdf/sprugj6c
> OMAPL138: http://www.ti.com/lit/gpn/omap-l138

Evidently the mcBsp specs won't tell you how the device is mapped within 
a given SoC. As for the OMAPL138 SoC, it looks more like an overview. 
You would need to refer to a detailed spec, one with register level 
description of the module.

> thanks again,
>
> Ran

Amicalement,
-- 
Albert.