Re: [PATCH v2 4/8] dmaengine: dw-edma: Pass dma_slave_config to dw_edma_device_transfer()

Damien Le Moal
2025-12-19T10:38:16Z

On 12/19/25 00:56, Frank Li wrote:
> Pass dma_slave_config to dw_edma_device_transfer() to support atomic
> configuration and descriptor preparation when a non-NULL config is
> provided to device_prep_config_sg().
>
> Tested-by: Niklas Cassel <cassel@kernel.org>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
> drivers/dma/dw-edma/dw-edma-core.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index e005b7bdaee156a3f4573b4734f50e3e47553dd2..1863254bf61eb892cb0cf8934e53b40d32027dfa 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -230,6 +230,15 @@ static int dw_edma_device_config(struct dma_chan *dchan,
> return 0;
> }
>
> +static struct dma_slave_config *
> +dw_edma_device_get_config(struct dma_chan *dchan,
> + struct dma_slave_config *config)
> +{
> + struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> +
> + return config ? config : &chan->config;
> +}

I would rewrite this as:

static struct dma_slave_config *
dw_edma_device_get_config(struct dma_chan *dchan,
struct dma_slave_config *config)
{
struct dw_edma_chan *chan;

if (config)
return config;

chan = dchan2dw_edma_chan(dchan);

return &chan->config;
}

That avoids the call to dchan2dw_edma_chan() if config is specified.

--
Damien Le Moal
Western Digital Research