[U-Boot] [PATCH V8 3/9] DWMMC: Initialise dwmci and resolve EMMC read write issues

[Jaehoon Chung]

Hi Amar,

I'm not sure that need to enable the auto-stop command feature.
why do you enable this feature? Is there any benefit?
Is it related with read/write issue?

Best Regards,
Jaehoon Chung

On 04/03/2013 11:08 PM, Amar wrote:
> This patch enumerates dwmci and set auto stop command during
> dwmci initialisation.
> EMMC read/write is not happening in current implementation
> due to improper fifo size computation. Hence modified the fifo size
> computation to resolve EMMC read write issues.
> 
> Signed-off-by: Amar <amarendra.xt at samsung.com>
> ---
> Changes since V1:
> 	1)Created the macros RX_WMARK_SHIFT and RX_WMARK_MASK in header file.
> 
> Changes since V2:
> 	1)Updation of commit message and resubmition of proper patch set.
> 
> Changes since V3:
> 	1)Updated to use the macro DWMCI_CTRL_SEND_AS_CCSD instead of
> 	the hard coded value (1 << 10).
> 
> Changes since V4:
> 	1)Updated the function dwmci_send_cmd() to use get_timer() instead
> 	of using mdelay(1).
> 
> Changes since V5:
> 	1)Updated in response to review comments.
> 
> Changes since V6:
> 	No change.
> 
> Changes since V7:
> 	1)Updated the function dwmci_setup_bus() to return 0 if (freq == 0). 
> 	This is to avoid the run time exception "raise:Signal # 8 caught".
> 
>  drivers/mmc/dw_mmc.c | 28 ++++++++++++++++++----------
>  1 file changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 4070d4e..963a515 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -129,13 +129,13 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  	unsigned int timeout = 100000;
>  	u32 retry = 10000;
>  	u32 mask, ctrl;
> +	ulong start = get_timer(0);
>  
>  	while (dwmci_readl(host, DWMCI_STATUS) & DWMCI_BUSY) {
> -		if (timeout == 0) {
> +		if (get_timer(start) > timeout) {
>  			printf("Timeout on data busy\n");
>  			return TIMEOUT;
>  		}
> -		timeout--;
>  	}
>  
>  	dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_ALL);
> @@ -143,7 +143,6 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  	if (data)
>  		dwmci_prepare_data(host, data);
>  
> -
>  	dwmci_writel(host, DWMCI_CMDARG, cmd->cmdarg);
>  
>  	if (data)
> @@ -231,9 +230,8 @@ static int dwmci_setup_bus(struct dwmci_host *host, u32 freq)
>  	int timeout = 10000;
>  	unsigned long sclk;
>  
> -	if (freq == host->clock)
> +	if ((freq == host->clock) || (freq == 0))
>  		return 0;
> -
>  	/*
>  	 * If host->mmc_clk didn't define,
>  	 * then assume that host->bus_hz is source clock value.
> @@ -314,7 +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, fifoth_val, ier;
>  
>  	dwmci_writel(host, DWMCI_PWREN, 1);
>  
> @@ -323,6 +321,14 @@ static int dwmci_init(struct mmc *mmc)
>  		return -1;
>  	}
>  
> +	/* Enumerate at 400KHz */
> +	dwmci_setup_bus(host, mmc->f_min);
> +
> +	/* Set auto stop command */
> +	ier = dwmci_readl(host, DWMCI_CTRL);
> +	ier |= DWMCI_CTRL_SEND_AS_CCSD;
> +	dwmci_writel(host, DWMCI_CTRL, ier);
> +
>  	dwmci_writel(host, DWMCI_RINTSTS, 0xFFFFFFFF);
>  	dwmci_writel(host, DWMCI_INTMASK, 0);
>  
> @@ -332,11 +338,13 @@ static int dwmci_init(struct mmc *mmc)
>  	dwmci_writel(host, DWMCI_BMOD, 1);
>  
>  	fifo_size = dwmci_readl(host, DWMCI_FIFOTH);
> -	if (host->fifoth_val)
> +	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) |
> -			TX_WMARK(fifo_size/2);
> +	} else {
> +		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_CLKENA, 0);
>