Re: [PATCH 06/13] DMAENGINE: driver for the ARM PL080/PL081 PrimeCells

From: Maurus Cuelenaere
Date: Tue Jun 15 2010 - 08:27:43 EST


Op 15-06-10 13:39, Jassi Brar schreef:
> On Tue, Jun 15, 2010 at 8:17 PM, Maurus Cuelenaere
> <mcuelenaere@xxxxxxxxx> wrote:
>
>> Op 15-06-10 12:45, Jassi Brar schreef:
>>
>>> On Tue, Jun 15, 2010 at 7:25 PM, Kukjin Kim <kgene.kim@xxxxxxxxxxx> wrote:
>>>
>>>> Linus Walleij wrote:
>>>>
>>>>> This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
>>>>> based on the implementation earlier submitted by Peter Pearse.
>>>>> This is working like a charm for memcpy on the PB11MPCore, but
>>>>> slave DMA to devices is still not working.
>>>>>
>>>>> This DMA controller is used in mostly unmodified form in the ARM
>>>>> RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
>>>>> in the ST SPEAr platform.
>>>>>
>>>>> It has been converted to use the header from the Samsung PL080
>>>>> derivate instead of its own defintions, and can potentially support
>>>>> several controllers in the same system.
>>>>>
>>>>> Cc: Peter Pearse <peter.pearse@xxxxxxx>
>>>>> Cc: Ben Dooks <ben-linux@xxxxxxxxx>
>>>>> Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
>>>>>
>>>> Looks good, but please give me some time to test on the board(SMDK6410).
>>>> If any problem, let you know. Of course no problem, will ack.
>>>>
>>> Samsung doesn't use the DMA API, so this driver is unlikely to work.
>>>
>> It doesn't indeed, but it could be adapted to be a wrapper around the DMA engine API.
>> Or even better, the drivers could be adapted to use that API.
>>
> I don't particularly like the idea of making Samsung's drivers use the DMA API.
> IMHO the S3C dma api is better atm.
>

At the moment it is better, true. But I do think it'd be better to use a
generic API than an arch-specific one.
I'm not familiar enough with both of them to know what functionality is
currently missing but I do think that once the DMA engine API is up to
speed, it should replace the s3c one.

--
Maurus Cuelenaere

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/