Re: [PATCH v2 2/2] dma: rz-dmac: Fix destination and source data size setting

[Vinod Koul <vkoul@kernel.org>]

On 30-06-23, 17:17, Biju Das wrote:
> From: Hien Huynh <hien.huynh.px@renesas.com>

patch title should be dmaengine: xxx

> 
> Before setting DDS and SDS values, we need to clear its value first
> otherwise, we get incorrect results when we change/update the DMA bus
> width several times due to the 'OR' expression.


> 
> Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
> Signed-off-by: Hien Huynh <hien.huynh.px@renesas.com>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v1->v2:
>  * Updated patch header.
> ---
>  drivers/dma/sh/rz-dmac.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 229f642fde6b..331ea80f21b0 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -145,8 +145,10 @@ struct rz_dmac {
>  #define CHCFG_REQD			BIT(3)
>  #define CHCFG_SEL(bits)			((bits) & 0x07)
>  #define CHCFG_MEM_COPY			(0x80400008)
> -#define CHCFG_FILL_DDS(a)		(((a) << 16) & GENMASK(19, 16))
> -#define CHCFG_FILL_SDS(a)		(((a) << 12) & GENMASK(15, 12))
> +#define CHCFG_FILL_DDS_MASK		GENMASK(19, 16)
> +#define CHCFG_FILL_DDS(a)		(((a) << 16) & CHCFG_FILL_DDS_MASK)
> +#define CHCFG_FILL_SDS_MASK		GENMASK(15, 12)
> +#define CHCFG_FILL_SDS(a)		(((a) << 12) & CHCFG_FILL_SDS_MASK)

Suggestion: Consider using FIELD_PREP and FIELD_GET for this

>  #define CHCFG_FILL_TM(a)		(((a) & BIT(5)) << 22)
>  #define CHCFG_FILL_AM(a)		(((a) & GENMASK(4, 2)) << 6)
>  #define CHCFG_FILL_LVL(a)		(((a) & BIT(1)) << 5)
> @@ -607,12 +609,14 @@ static int rz_dmac_config(struct dma_chan *chan,
>  	if (val == CHCFG_DS_INVALID)
>  		return -EINVAL;
>  
> +	channel->chcfg &= ~CHCFG_FILL_DDS_MASK;
>  	channel->chcfg |= CHCFG_FILL_DDS(val);
>  
>  	val = rz_dmac_ds_to_val_mapping(config->src_addr_width);
>  	if (val == CHCFG_DS_INVALID)
>  		return -EINVAL;
>  
> +	channel->chcfg &= ~CHCFG_FILL_SDS_MASK;
>  	channel->chcfg |= CHCFG_FILL_SDS(val);
>  
>  	return 0;
> -- 
> 2.25.1

-- 
~Vinod