[PATCH] mmc: dw_mmc: move host->data_offset init earlier

[PATCH] mmc: dw_mmc: move host->data_offset init earlier

[James Hogan]

host->data_offset is initialised at the end of the probe function
depending on the VERID register, and is used for PIO operations. Move
this initialisation earlier, before IRQs or slots are initialised, to be
sure that PIO won't occur prior to host->data_offset being initialised.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Seungwon Jeon <tgih.jun@samsung.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Chris Ball <cjb@laptop.org>
---
Note, I didn't actually observe this problem occuring, but I think in
theory it could happen.

 drivers/mmc/host/dw_mmc.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 1a42c7c..7556456 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2289,6 +2289,18 @@ int dw_mci_probe(struct dw_mci *host)
 	mci_writel(host, CLKENA, 0);
 	mci_writel(host, CLKSRC, 0);
 
+	/*
+	 * In 2.40a spec, Data offset is changed.
+	 * Need to check the version-id and set data-offset for DATA register.
+	 */
+	host->verid = SDMMC_GET_VERID(mci_readl(host, VERID));
+	dev_info(host->dev, "Version ID is %04x\n", host->verid);
+
+	if (host->verid < DW_MMC_240A)
+		host->data_offset = DATA_OFFSET;
+	else
+		host->data_offset = DATA_240A_OFFSET;
+
 	tasklet_init(&host->tasklet, dw_mci_tasklet_func, (unsigned long)host);
 	host->card_workqueue = alloc_workqueue("dw-mci-card",
 			WQ_MEM_RECLAIM | WQ_NON_REENTRANT, 1);
@@ -2337,18 +2349,6 @@ int dw_mci_probe(struct dw_mci *host)
 		goto err_workqueue;
 	}
 
-	/*
-	 * In 2.40a spec, Data offset is changed.
-	 * Need to check the version-id and set data-offset for DATA register.
-	 */
-	host->verid = SDMMC_GET_VERID(mci_readl(host, VERID));
-	dev_info(host->dev, "Version ID is %04x\n", host->verid);
-
-	if (host->verid < DW_MMC_240A)
-		host->data_offset = DATA_OFFSET;
-	else
-		host->data_offset = DATA_240A_OFFSET;
-
 	if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO)
 		dev_info(host->dev, "Internal DMAC interrupt fix enabled.\n");
 
-- 
1.8.1.2

Re: [PATCH] mmc: dw_mmc: move host->data_offset init earlier

[Jaehoon Chung]

Hi James,

There is no reason that can't change the verid check position.
So this patch looks good to me.

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

Best Regards,
Jaehoon Chung

On 03/12/2013 07:43 PM, James Hogan wrote:
> host->data_offset is initialised at the end of the probe function
> depending on the VERID register, and is used for PIO operations. Move
> this initialisation earlier, before IRQs or slots are initialised, to be
> sure that PIO won't occur prior to host->data_offset being initialised.
> 
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Seungwon Jeon <tgih.jun@samsung.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Chris Ball <cjb@laptop.org>
> ---
> Note, I didn't actually observe this problem occuring, but I think in
> theory it could happen.
> 
>  drivers/mmc/host/dw_mmc.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 1a42c7c..7556456 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2289,6 +2289,18 @@ int dw_mci_probe(struct dw_mci *host)
>  	mci_writel(host, CLKENA, 0);
>  	mci_writel(host, CLKSRC, 0);
>  
> +	/*
> +	 * In 2.40a spec, Data offset is changed.
> +	 * Need to check the version-id and set data-offset for DATA register.
> +	 */
> +	host->verid = SDMMC_GET_VERID(mci_readl(host, VERID));
> +	dev_info(host->dev, "Version ID is %04x\n", host->verid);
> +
> +	if (host->verid < DW_MMC_240A)
> +		host->data_offset = DATA_OFFSET;
> +	else
> +		host->data_offset = DATA_240A_OFFSET;
> +
>  	tasklet_init(&host->tasklet, dw_mci_tasklet_func, (unsigned long)host);
>  	host->card_workqueue = alloc_workqueue("dw-mci-card",
>  			WQ_MEM_RECLAIM | WQ_NON_REENTRANT, 1);
> @@ -2337,18 +2349,6 @@ int dw_mci_probe(struct dw_mci *host)
>  		goto err_workqueue;
>  	}
>  
> -	/*
> -	 * In 2.40a spec, Data offset is changed.
> -	 * Need to check the version-id and set data-offset for DATA register.
> -	 */
> -	host->verid = SDMMC_GET_VERID(mci_readl(host, VERID));
> -	dev_info(host->dev, "Version ID is %04x\n", host->verid);
> -
> -	if (host->verid < DW_MMC_240A)
> -		host->data_offset = DATA_OFFSET;
> -	else
> -		host->data_offset = DATA_240A_OFFSET;
> -
>  	if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO)
>  		dev_info(host->dev, "Internal DMAC interrupt fix enabled.\n");
>  
> 

RE: [PATCH] mmc: dw_mmc: move host->data_offset init earlier

[Seungwon Jeon]

On Tuesday, March 12, 2013, James Hogan wrote:
> host->data_offset is initialised at the end of the probe function
> depending on the VERID register, and is used for PIO operations. Move
> this initialisation earlier, before IRQs or slots are initialised, to be
> sure that PIO won't occur prior to host->data_offset being initialised.
> 
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Seungwon Jeon <tgih.jun@samsung.com>

Acked-by: Seungwon Jeon <tgih.jun@samsung.com>

Re: [PATCH] mmc: dw_mmc: move host->data_offset init earlier

[Chris Ball]

Hi,

On Tue, Mar 12 2013, James Hogan wrote:
> host->data_offset is initialised at the end of the probe function
> depending on the VERID register, and is used for PIO operations. Move
> this initialisation earlier, before IRQs or slots are initialised, to be
> sure that PIO won't occur prior to host->data_offset being initialised.
>
> Signed-off-by: James Hogan <james.hogan@imgtec.com>
> Cc: Seungwon Jeon <tgih.jun@samsung.com>
> Cc: Jaehoon Chung <jh80.chung@samsung.com>
> Cc: Chris Ball <cjb@laptop.org>

Thanks, pushed to mmc-next for 3.10.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child