Hi,
Jingchang Lu wrote:
> The offset of all 8-/16-bit register in big-endian eDMA model are
s/register/registers/
> swapped in a 32-bit size opposite those in the little-endian model.
>
> The hardware Scatter/Gather requires the subsequent TCDs in memory
> to be auto loaded should retain little endian independent of the
> register endian model, the dma engine will do the swap if need.
>
> This patch also use regular assignment for tcd variables r/w
> instead of with io function previously that may not always be true.
>
> Signed-off-by: Jingchang Lu <jingchang.lu@xxxxxxxxxxxxx>
> ---
> changes in v3:
> use unsigned long instead of u32 in reg offset swap cast to avoid warning.
>
> changes in v2:
> simplify register offset swap calculation.
> use regular assignment for tcd variables r/w instead of io function.
>
> drivers/dma/fsl-edma.c | 106 ++++++++++++++++++++++++++-----------------------
> 1 file changed, 57 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
> index 3c5711d..9ca55ee 100644
> --- a/drivers/dma/fsl-edma.c
> +++ b/drivers/dma/fsl-edma.c
> @@ -177,16 +177,10 @@ struct fsl_edma_engine {
> /*
> * R/W functions for big- or little-endian registers
> * the eDMA controller's endian is independent of the CPU core's endian.
> + * for the big-endian IP module, the offset for 8-bit or 16-bit register
s/for/For/
> + * should also be swapped oposite to that in little-endian IP.
s/oposite/opposite/
[...]
> @@ -459,20 +460,27 @@ static void fill_tcd_params(struct fsl_edma_engine *edma,
> u16 csr = 0;
>
> /*
> - * eDMA hardware SGs require the TCD parameters stored in memory
> - * the same endian as the eDMA module so that they can be loaded
> - * automatically by the engine
> + * eDMA hardware SGs requires the TCDs to be auto loaded
> + * in the little endian whenver the register endian model,
"in little endian whatever the register endian model"
> + * So we put the value in little endian in memory, waitting
s/waitting/waiting/
> + * for fsl_set_tcd_params doing the swap.
fsl_set_tcd_params()
Lothar Waßmann
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