[U-Boot] [PATCH] mmc/dw_mmc: Fix DMA descriptor corruption

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi, Mischa,
Looks good to me.

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung

On 07/26/2013 09:08 PM, Mischa Jonker wrote:
> In dwmci_prepare_data, the descriptors are allocated for DMA transfer.
> These are allocated using the ALLOC_CACHE_ALIGN_BUFFER. This macro uses
> the stack to allocate these descriptors. This becomes a problem if the
> DMA transfer continues after the processor leaves the function in which
> the descriptors were allocated.
> 
> Therefore, I have moved the allocated of the buffers up one level, to
> dwmci_send_cmd(). The DMA transfer should be complete when leaving this
> function.
> 
> Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
> Cc: Alexey Brodkin <abrodkin@synopsys.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Andy Fleming <afleming@gmail.com>
> ---
>  drivers/mmc/dw_mmc.c |    7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index a82ee17..796a811 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -41,12 +41,11 @@ static void dwmci_set_idma_desc(struct dwmci_idmac *idmac,
>  }
>  
>  static void dwmci_prepare_data(struct dwmci_host *host,
> -		struct mmc_data *data)
> +		struct mmc_data *data, struct dwmci_idmac *cur_idmac)
>  {
>  	unsigned long ctrl;
>  	unsigned int i = 0, flags, cnt, blk_cnt;
>  	ulong data_start, data_end, start_addr;
> -	ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac, data->blocks);
>  
>  
>  	blk_cnt = data->blocks;
> @@ -111,6 +110,8 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  		struct mmc_data *data)
>  {
>  	struct dwmci_host *host = (struct dwmci_host *)mmc->priv;
> +	ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac,
> +				 data ? data->blocks : 0);
>  	int flags = 0, i;
>  	unsigned int timeout = 100000;
>  	u32 retry = 10000;
> @@ -127,7 +128,7 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  	dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_ALL);
>  
>  	if (data)
> -		dwmci_prepare_data(host, data);
> +		dwmci_prepare_data(host, data, cur_idmac);
>  
>  	dwmci_writel(host, DWMCI_CMDARG, cmd->cmdarg);
>  
>