On 12/05/19 10:41 PM, Angelo Dureghello wrote:
> Some controller as the ColdFire eshdc may require an endianness
> byte swap, becouse DMA read endianness is not configurable.
becouse -> because
Do any other drivers have this issue?
>
> Signed-off-by: Angelo Dureghello <angelo@xxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 19 +++++++++++++++++++
> drivers/mmc/host/sdhci.h | 7 +++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 97158344b862..317dcfb4bb4c 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2592,6 +2592,18 @@ static const struct mmc_host_ops sdhci_ops = {
> .card_busy = sdhci_card_busy,
> };
>
> +static void sdhci_be_to_le(char *buff, u32 length)
> +{
> + int i, size = length >> 2;
> + u32 *buffer = (u32 *)buff;
> + u32 temp;
> +
> + for (i = 0; i < size; i++) {
> + temp = *buffer;
> + *buffer++ = __le32_to_cpu(temp);
> + }
> +}
> +
> /*****************************************************************************\
> * *
> * Request done *
> @@ -2647,6 +2659,13 @@ static bool sdhci_request_done(struct sdhci_host *host)
> host->bounce_addr,
> host->bounce_buffer_size,
> DMA_FROM_DEVICE);
> +
> + if (host->quirks2 &
> + SDHCI_QUIRK2_USE_32BIT_BE_DMA_SWAP)
> + sdhci_be_to_le(
> + host->bounce_buffer,
> + length);
How come it only affects the bounce buffer? What about if there is no
bounce buffer?
> +
> sg_copy_from_buffer(data->sg,
> data->sg_len,
> host->bounce_buffer,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index d6bcc584c92b..38fa69678cec 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -486,6 +486,13 @@ struct sdhci_host {
> */
> #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT (1<<18)
>
> +/*
> + * On some architectures, as ColdFire/m68k, native endianness is big endian,
> + * and the dma buffer is filled in big endian order only (no other options).
> + * So, a swap is needed for these specific cases.
> + */
> +#define SDHCI_QUIRK2_USE_32BIT_BE_DMA_SWAP (1<<19)
> +
> int irq; /* Device IRQ */
> void __iomem *ioaddr; /* Mapped address */
> char *bounce_buffer; /* For packing SDMA reads/writes */
>
