Subject: Re: [PATCH RFC v4 2/5] dma: mpc512x: add support for peripheral transfers

From: Lars-Peter Clausen <[email-masked]>
Date: Fri, 06 Dec 2013 21:35:01 +0100

On 12/06/2013 09:27 PM, Alexander Popov wrote:
> 2013/10/6 Gerhard Sittig <[email-masked]>:
>> On Thu, Oct 03, 2013 at 18:06 +0400, Alexander Popov wrote:
>>> +
>>> +             spin_lock_irqsave(&mchan->lock, flags);
>>> +
>>> +             if (cfg->direction == DMA_DEV_TO_MEM) {
>>
>> Note that cfg->direction is of a different type than
>> DMA_DEV_TO_MEM (of different type than the 'direction' parameter
>> in the preparation routine) -- it's mere coincidence that the
>> numeric values happen to match at the moment.
>
> Gerhard, it seems to me that this code is correct.
> Cite from dmaengine.h:
>
>    * struct dma_slave_config - dma slave channel runtime config
>    * @direction: whether the data shall go in or out on this slave
>    * channel, right now. DMA_TO_DEVICE and DMA_FROM_DEVICE are
>    * legal values, DMA_BIDIRECTIONAL is not acceptable since we
>    * need to differentiate source and target addresses.
>    ...
>    struct dma_slave_config {
>            enum dma_transfer_direction direction;
>            ...
>    };
>
> The comment above the definition is obsolete, isn't it?

Yes, the comment seems to be out of date. Care to send a patch fixing it?

- Lars