Re: [PATCH v5 2/3] mmc: sdhci: add quirks for be to le byte swapping

[Adrian Hunter <adrian.hunter@intel.com>]

On 16/05/20 1:27 am, Angelo Dureghello wrote:
> Some controller as the ColdFire eshdc may require an endianness
> byte swap, becouse DMA read endianness is not configurable.

becouse -> because

Needs a bit more explanation i.e.

Facilitate using the bounce buffer for this by adding ->copy_to_bounce_buffer().

Nevertheless:

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> 
> Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
> ---
> Changes for v3:
> - add post request callback
> Changes for v4:
> none
> Changes for v5:
> - remove useless comment before swapping bounce buffer
> - rename pre_dma_transfer to copy_to_bounce_buffer
> ---
>  drivers/mmc/host/sdhci.c | 9 ++++++---
>  drivers/mmc/host/sdhci.h | 2 ++
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 3f716466fcfd..b7ba43e3b7c5 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -634,9 +634,12 @@ static int sdhci_pre_dma_transfer(struct sdhci_host *host,
>  		}
>  		if (mmc_get_dma_dir(data) == DMA_TO_DEVICE) {
>  			/* Copy the data to the bounce buffer */
> -			sg_copy_to_buffer(data->sg, data->sg_len,
> -					  host->bounce_buffer,
> -					  length);
> +			if (host->ops->copy_to_bounce_buffer) {
> +				host->ops->copy_to_bounce_buffer(host, data);
> +			} else {
> +				sg_copy_to_buffer(data->sg, data->sg_len,
> +						  host->bounce_buffer, length);
> +			}
>  		}
>  		/* Switch ownership to the DMA */
>  		dma_sync_single_for_device(host->mmc->parent,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 79dffbb731d3..632ea297bb60 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -653,6 +653,8 @@ struct sdhci_ops {
>  	void	(*voltage_switch)(struct sdhci_host *host);
>  	void	(*adma_write_desc)(struct sdhci_host *host, void **desc,
>  				   dma_addr_t addr, int len, unsigned int cmd);
> +	void	(*copy_to_bounce_buffer)(struct sdhci_host *host,
> +					 struct mmc_data *data);
>  	void	(*request_done)(struct sdhci_host *host,
>  				struct mmc_request *mrq);
>  };
>