Re: [PATCH 3/4] dmaengine: fsl-edma: support little endian for edma driver

Vinod Koul
2019-05-21T04:38:13Z

On 06-05-19, 09:03, Peng Ma wrote:
> improve edma driver to support little endian.

Can you explain a bit more how adding the below lines adds little endian
support...

>
> Signed-off-by: Peng Ma <peng.ma@nxp.com>
> ---
> drivers/dma/fsl-edma-common.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
> index 680b2a0..6bf238e 100644
> --- a/drivers/dma/fsl-edma-common.c
> +++ b/drivers/dma/fsl-edma-common.c
> @@ -83,9 +83,14 @@ void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan,
> u32 ch = fsl_chan->vchan.chan.chan_id;
> void __iomem *muxaddr;
> unsigned int chans_per_mux, ch_off;
> + int endian_diff[4] = {3, 1, -1, -3};
>
> chans_per_mux = fsl_chan->edma->n_chans / DMAMUX_NR;
> ch_off = fsl_chan->vchan.chan.chan_id % chans_per_mux;
> +
> + if (!fsl_chan->edma->big_endian)
> + ch_off += endian_diff[ch_off % 4];
> +
> muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux];
> slot = EDMAMUX_CHCFG_SOURCE(slot);
>
> --
> 1.7.1

--
~Vinod