RE: [PATCH] mmc: sdhci-s3c: add quirk about BROKEN_ADMA_ZEROLEN_DESC

[Seungwon Jeon <tgih.jun@samsung.com>]

Hi,

I don't know meaning of QUIRK_BROKEN_ADMA_ZEROLEN_DESC exactly.
Is there any problem in ADMA descriptors?
Could you explain for this?

The following table is for ADMA length field from Host controller spec.
The maximum data length descriptor line is less than 64KiB.
Samsung also conforms this.
----------------------------------
Length Field  | Value of Length
----------------------------------
0000h		| 65536 bytes
0001h		| 1 byte
0002h		| 2bytes
... 		| ...
FFFFh		| 65535 bytes
----------------------------------

Best regards,
Seungwon Jeon.

Jaehoon Chung wrote: 
> This patch is added the quirk for Samsung SoCs.
> 
> Samsung SoCs need to set QUIRK_BROKEN_ADMA_ZEROLEN_DESC.
> (If ADMA operation is more than 65535, maybe set by zero.)
> 
> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  drivers/mmc/host/sdhci-s3c.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
> index 460ffaf..03da44a 100644
> --- a/drivers/mmc/host/sdhci-s3c.c
> +++ b/drivers/mmc/host/sdhci-s3c.c
> @@ -502,6 +502,9 @@ static int __devinit sdhci_s3c_probe(struct
> platform_device *pdev)
>  	/* This host supports the Auto CMD12 */
>  	host->quirks |= SDHCI_QUIRK_MULTIBLOCK_READ_ACMD12;
> 
> +	/* Samsung SoCs need BROKEN_ADMA_ZEROLEN_DESC */
> +	host->quirks |= SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC;
> +
>  	if (pdata->cd_type == S3C_SDHCI_CD_NONE ||
>  	    pdata->cd_type == S3C_SDHCI_CD_PERMANENT)
>  		host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> --
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