[PATCH 1/2 v2] sh_mobile_ceu: add soft reset function

[PATCH 1/2 v2] sh_mobile_ceu: add soft reset function

[Kuninori Morimoto]

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
---
v1 -> v2

o it use msleep
o it judge in_atomic or not

it judge in_atomic because sh_mobile_ceu_soft_reset
will also be called from atomic.

 drivers/media/video/sh_mobile_ceu_camera.c |   36 ++++++++++++++++++++++++---
 1 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
index 0db88a5..3741ad6 100644
--- a/drivers/media/video/sh_mobile_ceu_camera.c
+++ b/drivers/media/video/sh_mobile_ceu_camera.c
@@ -135,6 +135,36 @@ static u32 ceu_read(struct sh_mobile_ceu_dev *priv, unsigned long reg_offs)
 	return ioread32(priv->base + reg_offs);
 }
 
+static void sh_mobile_ceu_soft_reset(struct sh_mobile_ceu_dev *pcdev)
+{
+	int t;
+	int atomic = in_atomic();
+
+	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
+
+	t = 10000;
+	while (t--) {
+		if (!(ceu_read(pcdev, CAPSR) & (1 << 16)))
+			break;
+
+		if (atomic)
+			cpu_relax();
+		else
+			msleep(1);
+	}
+
+	t = 10000;
+	while (t--) {
+		if (!(ceu_read(pcdev, CSTSR) & 1))
+			break;
+
+		if (atomic)
+			cpu_relax();
+		else
+			msleep(1);
+	}
+}
+
 /*
  *  Videobuf operations
  */
@@ -366,9 +396,7 @@ static int sh_mobile_ceu_add_device(struct soc_camera_device *icd)
 
 	clk_enable(pcdev->clk);
 
-	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
-	while (ceu_read(pcdev, CSTSR) & 1)
-		msleep(1);
+	sh_mobile_ceu_soft_reset(pcdev);
 
 	pcdev->icd = icd;
 err:
@@ -386,7 +414,7 @@ static void sh_mobile_ceu_remove_device(struct soc_camera_device *icd)
 
 	/* disable capture, disable interrupts */
 	ceu_write(pcdev, CEIER, 0);
-	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
+	sh_mobile_ceu_soft_reset(pcdev);
 
 	/* make sure active buffer is canceled */
 	spin_lock_irqsave(&pcdev->lock, flags);
-- 
1.6.0.4

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Re: [PATCH 1/2 v2] sh_mobile_ceu: add soft reset function

[Guennadi Liakhovetski]

On Thu, 6 Aug 2009, Kuninori Morimoto wrote:

> 
> Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>

Ok, I'm away for a week starting today, I'll have a look at your patches 
after I come back then.

Thanks
Guennadi

> ---
> v1 -> v2
> 
> o it use msleep
> o it judge in_atomic or not
> 
> it judge in_atomic because sh_mobile_ceu_soft_reset
> will also be called from atomic.
> 
>  drivers/media/video/sh_mobile_ceu_camera.c |   36 ++++++++++++++++++++++++---
>  1 files changed, 32 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
> index 0db88a5..3741ad6 100644
> --- a/drivers/media/video/sh_mobile_ceu_camera.c
> +++ b/drivers/media/video/sh_mobile_ceu_camera.c
> @@ -135,6 +135,36 @@ static u32 ceu_read(struct sh_mobile_ceu_dev *priv, unsigned long reg_offs)
>  	return ioread32(priv->base + reg_offs);
>  }
>  
> +static void sh_mobile_ceu_soft_reset(struct sh_mobile_ceu_dev *pcdev)
> +{
> +	int t;
> +	int atomic = in_atomic();
> +
> +	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
> +
> +	t = 10000;
> +	while (t--) {
> +		if (!(ceu_read(pcdev, CAPSR) & (1 << 16)))
> +			break;
> +
> +		if (atomic)
> +			cpu_relax();
> +		else
> +			msleep(1);
> +	}
> +
> +	t = 10000;
> +	while (t--) {
> +		if (!(ceu_read(pcdev, CSTSR) & 1))
> +			break;
> +
> +		if (atomic)
> +			cpu_relax();
> +		else
> +			msleep(1);
> +	}
> +}
> +
>  /*
>   *  Videobuf operations
>   */
> @@ -366,9 +396,7 @@ static int sh_mobile_ceu_add_device(struct soc_camera_device *icd)
>  
>  	clk_enable(pcdev->clk);
>  
> -	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
> -	while (ceu_read(pcdev, CSTSR) & 1)
> -		msleep(1);
> +	sh_mobile_ceu_soft_reset(pcdev);
>  
>  	pcdev->icd = icd;
>  err:
> @@ -386,7 +414,7 @@ static void sh_mobile_ceu_remove_device(struct soc_camera_device *icd)
>  
>  	/* disable capture, disable interrupts */
>  	ceu_write(pcdev, CEIER, 0);
> -	ceu_write(pcdev, CAPSR, 1 << 16); /* reset */
> +	sh_mobile_ceu_soft_reset(pcdev);
>  
>  	/* make sure active buffer is canceled */
>  	spin_lock_irqsave(&pcdev->lock, flags);
> -- 
> 1.6.0.4
> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

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Re: [PATCH 1/2 v2] sh_mobile_ceu: add soft reset function

[Magnus Damm]

Hi Morimoto-san,

Thanks for your work on this.

On Thu, Aug 6, 2009 at 9:49 AM, Kuninori
Morimoto<morimoto.kuninori@renesas.com> wrote:
>
> Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
> ---
> v1 -> v2
>
> o it use msleep
> o it judge in_atomic or not
>
> it judge in_atomic because sh_mobile_ceu_soft_reset
> will also be called from atomic.

If the time required for soft reset is short enough then you probably
want to use udelay() instead. And if soft delay takes long time then
you don't want to do it from interrupt context anyway. Please update
the patch after summer vacation.

Cheers,

/ magnus

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