Re: [PATCH] sdhci: Add new quirk in sdhci driver and update ADMA descriptor build.

[Ben Dooks <ben-linux@fluff.org>]

On Tue, Sep 08, 2009 at 02:41:59PM +0900, thomas.ab@samsung.com wrote:
> From: Thomas Abraham <thomas.ab@samsung.com>
> 
> The s3c6410 sdhci controller does not support the 'End' attribute and
> NOP attribute in the same 8-Byte ADMA descriptor. This patch adds a
> new quirk to identify sdhci host contollers with such behaviour.
> In addition to this, for controllers using the new quirk, the last
> entry in the ADMA descritor table is marked with the 'End' attribute
> (instead of using a NOP descriptor with 'End' attribute).

This is very useful to know, I'd say this would be a useful quirk to
add to the SDHCI driver to see if we can get ADMA working on the S3C64XX
series.
 
> Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
> ---
>  drivers/mmc/host/sdhci.c |   35 ++++++++++++++++++++++-------------
>  drivers/mmc/host/sdhci.h |    2 ++
>  2 files changed, 24 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index fc96f8c..27a3447 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -487,19 +487,28 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
>  		WARN_ON((desc - host->adma_desc) > (128 * 2 + 1) * 4);
>  	}
>  
> -	/*
> -	 * Add a terminating entry.
> -	 */
> -	desc[7] = 0;
> -	desc[6] = 0;
> -	desc[5] = 0;
> -	desc[4] = 0;
> -
> -	desc[3] = 0;
> -	desc[2] = 0;
> -
> -	desc[1] = 0x00;
> -	desc[0] = 0x03; /* nop, end, valid */
> +	if (host->quirks & SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC) {
> +		/*
> +		* Mark the last descriptor as the terminating descriptor
> +		*/
> +		if (desc != host->adma_desc) {
> +			desc -= 8;
> +			desc[0] |= 0x2; /* end */
> +		}
> +	} else {
> +		/*
> +		* Add a terminating entry.
> +		*/
> +		desc[7] = 0;
> +		desc[6] = 0;
> +		desc[5] = 0;
> +		desc[4] = 0;
> +
> +		desc[3] = 0;
> +		desc[2] = 0;
> +		desc[1] = 0x00;
> +		desc[0] = 0x03; /* nop, end, valid */
> +	}
>  
>  	/*
>  	 * Resync align buffer as we might have changed it.
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index c77e9ff..e954116 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -232,6 +232,8 @@ struct sdhci_host {
>  #define SDHCI_QUIRK_FORCE_1_BIT_DATA			(1<<22)
>  /* Controller needs 10ms delay between applying power and clock */
>  #define SDHCI_QUIRK_DELAY_AFTER_POWER			(1<<23)
> +/* Controller cannot support End Attribute in NOP ADMA descriptor */
> +#define SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC		(1<<24)
>  
>  	int			irq;		/* Device IRQ */
>  	void __iomem *		ioaddr;		/* Mapped address */
> -- 
> 1.5.3.4
> 
> 
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-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.