Re: [PATCH, RFC] MIPS: jz4740: use dma filter function

From: Måns Rullgård
Date: Tue Jan 06 2015 - 07:47:10 EST


Lars-Peter Clausen <lars@xxxxxxxxxx> writes:

> On 01/05/2015 11:39 PM, Arnd Bergmann wrote:
>> As discussed on the topic of shmobile DMA today, jz4740 is the only
>> user of the slave_id field in dma_slave_config besides shmobile. This
>> use is really incompatible with the way that other drivers use the
>> dmaengine API, so we should get rid of it.
>
> Do you have a link to that discussion?
>
>>
>> This adds a trivial filter function that uses the filter param to
>> pass the dma type, and uses that in both drivers.
>
> In my opinion that's just from bad to worse. Using filter functions
> isn't that great in the first place. And using them to pass data from
> the consumer to the DMA provider is just a horrible abuse of the API.

It seems to me the only sane way to use the dmaengine API is in
conjunction with DT.

--
Måns Rullgård
mans@xxxxxxxxx
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