[PATCH 1/7] mmc: sdhci: clear auto cmd setting bits for no data cmds

[Shawn Guo]

On Mon, Oct 21, 2013 at 10:27:01PM +0800, Dong Aisheng wrote:
> The auto cmd settings bits should be cleared before sending new commands
> or we may receive command timeout error for normal commands due to wrongly
> pre-sent auto cmd.
> 
> e.g. we receive CMD13 timeout error due to ACMD23 is wrongly enabled
> by former data commands.
> 
> mmc2: new high speed DDR MMC card at address 0001
> mmcblk1: mmc2:0001 SEM08G 7.39 GiB
> mmcblk1boot0: mmc2:0001 SEM08G partition 1 2.00 MiB
> mmcblk1boot1: mmc2:0001 SEM08G partition 2 2.00 MiB
> mmcblk1rpmb: mmc2:0001 SEM08G partition 3 128 KiB
>  mmcblk1: p1 p2 p3 p4 < p5 p6 p7 >
> mmc2: Timeout waiting for hardware interrupt.
>  mmcblk1boot1: unknown partition table
> mmc2: Timeout waiting for hardware interrupt.
>  mmcblk1boot0: unknown partition table
> 
> Signed-off-by: Dong Aisheng <b29396 at freescale.com>
> ---
>  drivers/mmc/host/sdhci.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index a21a710..f868e9b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -898,6 +898,11 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
>  	u16 mode;
>  	struct mmc_data *data = cmd->data;
>  
> +	/* clear Auto CMD settings for no data CMDs */
> +	mode = sdhci_readw(host, SDHCI_TRANSFER_MODE);
> +	sdhci_writew(host, mode & ~(SDHCI_TRNS_AUTO_CMD12 |
> +			SDHCI_TRNS_AUTO_CMD23), SDHCI_TRANSFER_MODE);
> +

IMO, it will be more readable if we move the code into the if-clause
of (data == NULL), something like:

	if (data == NULL) {
		/* clear Auto CMD settings for no data CMDs */
		mode = sdhci_readw(host, SDHCI_TRANSFER_MODE);
		mode &= SDHCI_TRNS_AUTO_CMD12 | SDHCI_TRNS_AUTO_CMD23;
		sdhci_writew(host, mode, SDHCI_TRANSFER_MODE);
	}

Shawn

>  	if (data == NULL)
>  		return;
>  
> -- 
> 1.7.2.rc3
> 
>