[U-Boot] [PATCH 1/3] mmc: dw_mmc: change the read/write order under fifo mode

[Jaehoon Chung]

Hi Jacob,

On 08/30/2016 02:26 AM, Jacob Chen wrote:
> From: "jacob2.chen" <jacob2.chen at rock-chips.com>
> 
> The former implement have a bug.
> It will cause wrong data reading sometimes.

Could you explain what bug is there?
> 
> 
> Signed-off-by: jacob2.chen <jacob2.chen at rock-chips.com>

Could you change from jacob2.chen to your name?

> ---
> 
>  drivers/mmc/dw_mmc.c | 32 +++++++++++++++++---------------
>  1 file changed, 17 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index afc674d..f072739 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -120,35 +120,37 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
>  
>  		if (host->fifo_mode && size) {
>  			len = 0;
> -			if (data->flags == MMC_DATA_READ) {
> -				if ((dwmci_readl(host, DWMCI_RINTSTS) &
> -				     DWMCI_INTMSK_RXDR)) {
> +			if (data->flags == MMC_DATA_READ &&
> +			    (mask & DWMCI_INTMSK_RXDR)) {
> +				while (size) {
>  					len = dwmci_readl(host, DWMCI_STATUS);
>  					len = (len >> DWMCI_FIFO_SHIFT) &
> -						    DWMCI_FIFO_MASK;
> +					    DWMCI_FIFO_MASK;

this changing is related with bug?

>  					len = min(size, len);
>  					for (i = 0; i < len; i++)
>  						*buf++ =
> -						dwmci_readl(host, DWMCI_DATA);
> -					dwmci_writel(host, DWMCI_RINTSTS,
> -						     DWMCI_INTMSK_RXDR);
> +						    dwmci_readl(host,
> +								DWMCI_DATA);
> +					size = size > len ? (size - len) : 0;
>  				}
> -			} else {
> -				if ((dwmci_readl(host, DWMCI_RINTSTS) &
> -				     DWMCI_INTMSK_TXDR)) {
> +				dwmci_writel(host, DWMCI_RINTSTS,
> +					     DWMCI_INTMSK_RXDR);
> +			} else if (data->flags == MMC_DATA_WRITE &&
> +				   (mask & DWMCI_INTMSK_TXDR)) {

data->flags == MMC_DATA_WRITE doesn't need..flags are only two..
one is MMC_DATA_READ, otherwise it's MMC_DATA_WRITE.

> +				while (size) {
>  					len = dwmci_readl(host, DWMCI_STATUS);
>  					len = fifo_depth - ((len >>
> -						   DWMCI_FIFO_SHIFT) &
> -						   DWMCI_FIFO_MASK);
> +							     DWMCI_FIFO_SHIFT) &
> +							    DWMCI_FIFO_MASK);

ditto.

Best Regards,
Jaehoon Chung

>  					len = min(size, len);
>  					for (i = 0; i < len; i++)
>  						dwmci_writel(host, DWMCI_DATA,
>  							     *buf++);
> -					dwmci_writel(host, DWMCI_RINTSTS,
> -						     DWMCI_INTMSK_TXDR);
> +					size = size > len ? (size - len) : 0;
>  				}
> +				dwmci_writel(host, DWMCI_RINTSTS,
> +					     DWMCI_INTMSK_TXDR);
>  			}
> -			size = size > len ? (size - len) : 0;
>  		}
>  
>  		/* Data arrived correctly. */
>