Re: [PATCH 1/3] dmaengine: sh: rz-dmac: handle configs where one address is zero

[claudiu beznea <claudiu.beznea@tuxon.dev>]

On 30.09.2024 17:59, Wolfram Sang wrote:
> Configs like the ones coming from the MMC subsystem will have either
> 'src' or 'dst' zeroed, resulting in an unknown bus width. This will bail
> out on the RZ DMA driver because of the sanity check for a valid bus
> width. Reorder the code, so that the check will only be applied when the
> corresponding address is non-zero.
> 
> Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

> ---
>  drivers/dma/sh/rz-dmac.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 65a27c5a7bce..811389fc9cb8 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -601,22 +601,25 @@ static int rz_dmac_config(struct dma_chan *chan,
>  	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
>  	u32 val;
>  
> -	channel->src_per_address = config->src_addr;
>  	channel->dst_per_address = config->dst_addr;
> -
> -	val = rz_dmac_ds_to_val_mapping(config->dst_addr_width);
> -	if (val == CHCFG_DS_INVALID)
> -		return -EINVAL;
> -
>  	channel->chcfg &= ~CHCFG_FILL_DDS_MASK;
> -	channel->chcfg |= FIELD_PREP(CHCFG_FILL_DDS_MASK, val);
> +	if (channel->dst_per_address) {
> +		val = rz_dmac_ds_to_val_mapping(config->dst_addr_width);
> +		if (val == CHCFG_DS_INVALID)
> +			return -EINVAL;
>  
> -	val = rz_dmac_ds_to_val_mapping(config->src_addr_width);
> -	if (val == CHCFG_DS_INVALID)
> -		return -EINVAL;
> +		channel->chcfg |= FIELD_PREP(CHCFG_FILL_DDS_MASK, val);
> +	}
>  
> +	channel->src_per_address = config->src_addr;
>  	channel->chcfg &= ~CHCFG_FILL_SDS_MASK;
> -	channel->chcfg |= FIELD_PREP(CHCFG_FILL_SDS_MASK, val);
> +	if (channel->src_per_address) {
> +		val = rz_dmac_ds_to_val_mapping(config->src_addr_width);
> +		if (val == CHCFG_DS_INVALID)
> +			return -EINVAL;
> +
> +		channel->chcfg |= FIELD_PREP(CHCFG_FILL_SDS_MASK, val);
> +	}
>  
>  	return 0;
>  }