Vinod,
On 11/17/2016 02:50 PM, Peter Ujfalusi wrote:
> Some slave devices uses address window instead of single register for read
> and/or write of data. With the src/dst_port_window_size the address window
> can be specified and the DMAengine driver should use this information to
> correctly set up the transfer to loop within the provided window.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> include/linux/dmaengine.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index cc535a478bae..689d44327ef3 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -336,6 +336,12 @@ enum dma_slave_buswidth {
> * may or may not be applicable on memory sources.
> * @dst_maxburst: same as src_maxburst but for destination target
> * mutatis mutandis.
> + * @src_port_window_size: The length of the register area the data need to be
> + * written on the device side. It is only used for devices which is using an
> + * area instead of a single register to receive the data. Typically the DMA
> + * loops in this area in order to transfer the data.
> + * @dst_port_window_size: same as src_port_window_size but for the destination
> + * port.
I think this needs some clarification.
Should the src/dst_port_window_size be in bytes or in words? I think it would
make more sense to define it as number of words to be in sync with the
src/dst_maxburst.
I will need to resend the series either way. The omap-dma patch does not
handle this correctly.
> * @device_fc: Flow Controller Settings. Only valid for slave channels. Fill
> * with 'true' if peripheral should be flow controller. Direction will be
> * selected at Runtime.
> @@ -363,6 +369,8 @@ struct dma_slave_config {
> enum dma_slave_buswidth dst_addr_width;
> u32 src_maxburst;
> u32 dst_maxburst;
> + u32 src_port_window_size;
> + u32 dst_port_window_size;
> bool device_fc;
> unsigned int slave_id;
> };
>
--
Péter
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