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

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Submitter Mischa Jonker
Date July 26, 2013, 12:08 p.m.
Message ID <1374840494-31615-1-git-send-email-mjonker@synopsys.com>
Download mbox | patch
Permalink /patch/262141/
State Accepted
Delegated to: Pantelis Antoniou
Headers show

Comments

Mischa Jonker - July 26, 2013, 12:08 p.m.
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(-)
Jaehoon Chung - Aug. 2, 2013, 2:33 p.m.
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);
>  
>
Pantelis Antoniou - Sept. 6, 2013, 11:32 a.m.
Hi Mischa,

On Jul 26, 2013, at 3:08 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>

Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>

Thanks

Patch

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);