Re: [Question] which type of DMA taken by musb of beagle-xM(DM3730)?

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2010/10/31 Anand Gadiyar <gadiyar@xxxxxx>:
> On 10/27/2010 11:27 AM, Ming Lei wrote:

>> I don't think there is better fix in software than the two ones
>> you posted.
>>
>
> Looking at old mail threads, I remember Ajay had one objection to using PIO
> for unaligned transfers - when multiple DMA channels are repeatedly hit with
> unaligned DMA addresses, throughput and CPU load go for a toss. Ajay wanted
> to use the OMAP's SystemDMA engine to carry out the transfers in those
> cases. Anyway, that's a separate topic - and should probably be done after
> the DMA code is rewritten. (I think Felipe had some plans for that).

Seems DMA code should not be rewritten, only a DMA version
of musb_write_fifo and musb_read_fifo need to be implemented as
omap dependent code just like Blackfin,  right?

>
> I've posted a patch implementing the quick fix. Let me know if it solves the
> problem with g_ether.

Yes, I have tested your patch about g_ether on beagle xM, and it does fix
the DMA issue for unaligned buffer address.

>
> While fixing this, I noticed dma_channel_program also returns "true"
> while it is supposed to return an "int". Topic for a separate patch.
>
> - Anand
>


-- 
Lei Ming
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