[U-Boot] [PATCH V2] MMC: DWMMC: Fix FIFO_DEPTH calculation

[Simon Glass]

On Fri, May 24, 2013 at 5:45 AM, Rajeshwari Shinde <rajeshwari.s at samsung.com
> wrote:

> Current DWMMC driver used to give FIFO underrun/overrun error every 3rd
> time
> for mmc rescan command.
> In current code FIFO_DEPTH is getting calculated after reading the default
> FIFOTH
> register and extracting the RX_WMARK bits from it i.e (RX_WMARK =
> FIFO_DEPTH/2 -1).
> Instead of storing the correct value, we were recalculating the FIFO_DEPT
> each
>

DEPTH


> time which is not correct.
>
> Based on "[PATCH V9 3/9] DWMMC: Initialise dwmci and resolve EMMC read
> write issues"
> http://permalink.gmane.org/gmane.comp.boot-loaders.u-boot/160247
>
> Signed-off-by: Hatim Ali <hatim.rv at samsung.com>
> Signed-off-by: Rajeshwari Shinde <rajeshwari.s at samsung.com>
>

Acked-by: Simon Glass <sjg at chromium.org>

Tested on pit using 'mmc rescan' and saw no problems now.

Tested-by: Simon Glass <sjg at chromium.org>


> ---
> Changes in V2:
>         - remove fifoth_val local variable
>         - Rebased on top of "[PATCH V9 3/9] DWMMC: Initialise dwmci and
> resolve
>         EMMC read write issues".
>  drivers/mmc/dw_mmc.c |   14 ++++++--------
>  1 files changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 1307b12..5da20ed 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -312,7 +312,7 @@ static void dwmci_set_ios(struct mmc *mmc)
>  static int dwmci_init(struct mmc *mmc)
>  {
>         struct dwmci_host *host = (struct dwmci_host *)mmc->priv;
> -       u32 fifo_size, fifoth_val;
> +       u32 fifo_size;
>
>         dwmci_writel(host, DWMCI_PWREN, 1);
>
> @@ -332,15 +332,13 @@ static int dwmci_init(struct mmc *mmc)
>         dwmci_writel(host, DWMCI_IDINTEN, 0);
>         dwmci_writel(host, DWMCI_BMOD, 1);
>
> -       fifo_size = dwmci_readl(host, DWMCI_FIFOTH);
> -       fifo_size = ((fifo_size & RX_WMARK_MASK) >> RX_WMARK_SHIFT) + 1;
> -       if (host->fifoth_val) {
> -               fifoth_val = host->fifoth_val;
> -       } else {
> -               fifoth_val = MSIZE(0x2) | RX_WMARK(fifo_size / 2 - 1) |
> +       if (!host->fifoth_val) {
> +               fifo_size = dwmci_readl(host, DWMCI_FIFOTH);
> +               fifo_size = ((fifo_size & RX_WMARK_MASK) >>
> RX_WMARK_SHIFT) + 1;
> +               host->fifoth_val = MSIZE(0x2) | RX_WMARK(fifo_size / 2 -
> 1) |
>                         TX_WMARK(fifo_size / 2);
>         }
> -       dwmci_writel(host, DWMCI_FIFOTH, fifoth_val);
> +       dwmci_writel(host, DWMCI_FIFOTH, host->fifoth_val);
>
>         dwmci_writel(host, DWMCI_CLKENA, 0);
>         dwmci_writel(host, DWMCI_CLKSRC, 0);
> --
> 1.7.4.4
>
>