Cyclic DMA - callback properties and tx_status residue
linus.walleij at linaro.org
Fri May 11 08:24:10 EDT 2012
On Fri, May 11, 2012 at 5:00 AM, Vinod Koul <vinod.koul at linux.intel.com> wrote:
> Yes this needs to be mandatory. Let me add that explicitly.
> * @last: last completed DMA cookie
> * @used: last issued DMA cookie (i.e. the one in progress)
> - * @residue: the remaining number of bytes left to transmit
> - * on the selected transfer for states DMA_IN_PROGRESS and
> - * DMA_PAUSED if this is implemented in the driver, else 0
> + * @residue: is defined as:
> + * - for completed descriptor: 0
> + * - for descriptors which are in DMA_PAUSED, DMA_IN_PROGRESS:
> + * length - (current_addr - start_addr), where:
> + * length = descriptor dma length
> + * current_addr = current dma pointer queried for dma channel
> + * start_addr: starting address of this descriptor
> + * This is mandatory and needs to be correctly filled by driver
> Does this make it clear?
Looks good to me.
Acked-by: Linus Walleij <linus.walleij at linaro.org>
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