diff mbox

[v7,1/5] omap3isp: Modify clocks registration to avoid circular references

Message ID 1383076268-8984-2-git-send-email-s.nawrocki@samsung.com (mailing list archive)
State Awaiting Upstream
Headers show

Commit Message

The clock core code is going to be modified so clk_get() takes
reference on the clock provider module. Until the potential circular
reference issue is properly addressed, we pass NULL as as the first
argument to clk_register(), in order to disallow sub-devices taking
a reference on the ISP module back trough clk_get(). This should
prevent locking the modules in memory.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
This patch has been "compile tested" only.

---
 drivers/media/platform/omap3isp/isp.c |   22 ++++++++++++++++------
 drivers/media/platform/omap3isp/isp.h |    1 +
 2 files changed, 17 insertions(+), 6 deletions(-)

--
1.7.9.5

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Comments

Laurent Pinchart Oct. 29, 2013, 10:28 p.m. UTC | #1
Hi Sylwester,

Thank you for the patch.

On Tuesday 29 October 2013 20:51:04 Sylwester Nawrocki wrote:
> The clock core code is going to be modified so clk_get() takes
> reference on the clock provider module. Until the potential circular
> reference issue is properly addressed, we pass NULL as as the first
> argument to clk_register(), in order to disallow sub-devices taking
> a reference on the ISP module back trough clk_get(). This should
> prevent locking the modules in memory.
> 
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Do you plan to push this to mainline as part of this patch series ? I don't 
have pending patches for the omap3isp that would conflict with this patch, so 
that would be fine with me.

> ---
> This patch has been "compile tested" only.
> 
> ---
>  drivers/media/platform/omap3isp/isp.c |   22 ++++++++++++++++------
>  drivers/media/platform/omap3isp/isp.h |    1 +
>  2 files changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c
> b/drivers/media/platform/omap3isp/isp.c index df3a0ec..286027a 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -290,9 +290,11 @@ static int isp_xclk_init(struct isp_device *isp)
>  	struct clk_init_data init;
>  	unsigned int i;
> 
> +	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i)
> +		isp->xclks[i].clk = ERR_PTR(-EINVAL);
> +
>  	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i) {
>  		struct isp_xclk *xclk = &isp->xclks[i];
> -		struct clk *clk;
> 
>  		xclk->isp = isp;
>  		xclk->id = i == 0 ? ISP_XCLK_A : ISP_XCLK_B;
> @@ -305,10 +307,15 @@ static int isp_xclk_init(struct isp_device *isp)
>  		init.num_parents = 1;
> 
>  		xclk->hw.init = &init;
> -
> -		clk = devm_clk_register(isp->dev, &xclk->hw);
> -		if (IS_ERR(clk))
> -			return PTR_ERR(clk);
> +		/*
> +		 * The first argument is NULL in order to avoid circular
> +		 * reference, as this driver takes reference on the
> +		 * sensor subdevice modules and the sensors would take
> +		 * reference on this module through clk_get().
> +		 */
> +		xclk->clk = clk_register(NULL, &xclk->hw);
> +		if (IS_ERR(xclk->clk))
> +			return PTR_ERR(xclk->clk);
> 
>  		if (pdata->xclks[i].con_id == NULL &&
>  		    pdata->xclks[i].dev_id == NULL)
> @@ -320,7 +327,7 @@ static int isp_xclk_init(struct isp_device *isp)
> 
>  		xclk->lookup->con_id = pdata->xclks[i].con_id;
>  		xclk->lookup->dev_id = pdata->xclks[i].dev_id;
> -		xclk->lookup->clk = clk;
> +		xclk->lookup->clk = xclk->clk;
> 
>  		clkdev_add(xclk->lookup);
>  	}
> @@ -335,6 +342,9 @@ static void isp_xclk_cleanup(struct isp_device *isp)
>  	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i) {
>  		struct isp_xclk *xclk = &isp->xclks[i];
> 
> +		if (!IS_ERR(xclk->clk))
> +			clk_unregister(xclk->clk);
> +
>  		if (xclk->lookup)
>  			clkdev_drop(xclk->lookup);
>  	}
> diff --git a/drivers/media/platform/omap3isp/isp.h
> b/drivers/media/platform/omap3isp/isp.h index cd3eff4..1498f2b 100644
> --- a/drivers/media/platform/omap3isp/isp.h
> +++ b/drivers/media/platform/omap3isp/isp.h
> @@ -135,6 +135,7 @@ struct isp_xclk {
>  	struct isp_device *isp;
>  	struct clk_hw hw;
>  	struct clk_lookup *lookup;
> +	struct clk *clk;
>  	enum isp_xclk_id id;
> 
>  	spinlock_t lock;	/* Protects enabled and divider */
Sebastian Reichel Oct. 29, 2013, 11:28 p.m. UTC | #2
Hi,

On Tue, Oct 29, 2013 at 11:28:37PM +0100, Laurent Pinchart wrote:
> On Tuesday 29 October 2013 20:51:04 Sylwester Nawrocki wrote:
> > The clock core code is going to be modified so clk_get() takes
> > reference on the clock provider module. Until the potential circular
> > reference issue is properly addressed, we pass NULL as as the first
> > argument to clk_register(), in order to disallow sub-devices taking
> > a reference on the ISP module back trough clk_get(). This should
> > prevent locking the modules in memory.
> > 
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Do you plan to push this to mainline as part of this patch series ? I don't 
> have pending patches for the omap3isp that would conflict with this patch, so 
> that would be fine with me.

I plan to add support for DT to omap3isp + ADP1653 shortly. I have
not yet started to work on this, but expect to send some first RFC
patches in November.

-- Sebastian
Laurent Pinchart Oct. 29, 2013, 11:55 p.m. UTC | #3
Hi Sebastian,

On Wednesday 30 October 2013 00:28:39 Sebastian Reichel wrote:
> On Tue, Oct 29, 2013 at 11:28:37PM +0100, Laurent Pinchart wrote:
> > On Tuesday 29 October 2013 20:51:04 Sylwester Nawrocki wrote:
> > > The clock core code is going to be modified so clk_get() takes
> > > reference on the clock provider module. Until the potential circular
> > > reference issue is properly addressed, we pass NULL as as the first
> > > argument to clk_register(), in order to disallow sub-devices taking
> > > a reference on the ISP module back trough clk_get(). This should
> > > prevent locking the modules in memory.
> > > 
> > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> > > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> > 
> > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > Do you plan to push this to mainline as part of this patch series ? I
> > don't have pending patches for the omap3isp that would conflict with this
> > patch, so that would be fine with me.
> 
> I plan to add support for DT to omap3isp + ADP1653 shortly. I have
> not yet started to work on this, but expect to send some first RFC
> patches in November.

That's very nice to hear ! And thanks for the heads up, I would have started 
working on it shortly.
Sylwester Nawrocki Oct. 29, 2013, 11:57 p.m. UTC | #4
Hi Laurent,

(adding Mauro and LMML at Cc)

On 10/29/2013 11:28 PM, Laurent Pinchart wrote:
> Hi Sylwester,
>
> Thank you for the patch.
>
> On Tuesday 29 October 2013 20:51:04 Sylwester Nawrocki wrote:
>> The clock core code is going to be modified so clk_get() takes
>> reference on the clock provider module. Until the potential circular
>> reference issue is properly addressed, we pass NULL as as the first
>> argument to clk_register(), in order to disallow sub-devices taking
>> a reference on the ISP module back trough clk_get(). This should
>> prevent locking the modules in memory.
>>
>> Cc: Laurent Pinchart<laurent.pinchart@ideasonboard.com>
>> Signed-off-by: Sylwester Nawrocki<s.nawrocki@samsung.com>
>> Signed-off-by: Kyungmin Park<kyungmin.park@samsung.com>
>
> Acked-by: Laurent Pinchart<laurent.pinchart@ideasonboard.com>
>
> Do you plan to push this to mainline as part of this patch series ? I don't
> have pending patches for the omap3isp that would conflict with this patch, so
> that would be fine with me.

Thanks, yes I thought this patch might be merged together through the clk
tree, if Mike is willing to take it and we get yours and Mauro's Ack on it.

>> ---
>> This patch has been "compile tested" only.
>>
>> ---
>>   drivers/media/platform/omap3isp/isp.c |   22 ++++++++++++++++------
>>   drivers/media/platform/omap3isp/isp.h |    1 +
>>   2 files changed, 17 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/platform/omap3isp/isp.c
>> b/drivers/media/platform/omap3isp/isp.c index df3a0ec..286027a 100644
>> --- a/drivers/media/platform/omap3isp/isp.c
>> +++ b/drivers/media/platform/omap3isp/isp.c
>> @@ -290,9 +290,11 @@ static int isp_xclk_init(struct isp_device *isp)
>>   	struct clk_init_data init;
>>   	unsigned int i;
>>
>> +	for (i = 0; i<  ARRAY_SIZE(isp->xclks); ++i)
>> +		isp->xclks[i].clk = ERR_PTR(-EINVAL);
>> +
>>   	for (i = 0; i<  ARRAY_SIZE(isp->xclks); ++i) {
>>   		struct isp_xclk *xclk =&isp->xclks[i];
>> -		struct clk *clk;
>>
>>   		xclk->isp = isp;
>>   		xclk->id = i == 0 ? ISP_XCLK_A : ISP_XCLK_B;
>> @@ -305,10 +307,15 @@ static int isp_xclk_init(struct isp_device *isp)
>>   		init.num_parents = 1;
>>
>>   		xclk->hw.init =&init;
>> -
>> -		clk = devm_clk_register(isp->dev,&xclk->hw);
>> -		if (IS_ERR(clk))
>> -			return PTR_ERR(clk);
>> +		/*
>> +		 * The first argument is NULL in order to avoid circular
>> +		 * reference, as this driver takes reference on the
>> +		 * sensor subdevice modules and the sensors would take
>> +		 * reference on this module through clk_get().
>> +		 */
>> +		xclk->clk = clk_register(NULL,&xclk->hw);
>> +		if (IS_ERR(xclk->clk))
>> +			return PTR_ERR(xclk->clk);
>>
>>   		if (pdata->xclks[i].con_id == NULL&&
>>   		pdata->xclks[i].dev_id == NULL)
>> @@ -320,7 +327,7 @@ static int isp_xclk_init(struct isp_device *isp)
>>
>>   		xclk->lookup->con_id = pdata->xclks[i].con_id;
>>   		xclk->lookup->dev_id = pdata->xclks[i].dev_id;
>> -		xclk->lookup->clk = clk;
>> +		xclk->lookup->clk = xclk->clk;
>>
>>   		clkdev_add(xclk->lookup);
>>   	}
>> @@ -335,6 +342,9 @@ static void isp_xclk_cleanup(struct isp_device *isp)
>>   	for (i = 0; i<  ARRAY_SIZE(isp->xclks); ++i) {
>>   		struct isp_xclk *xclk =&isp->xclks[i];
>>
>> +		if (!IS_ERR(xclk->clk))
>> +			clk_unregister(xclk->clk);
>> +
>>   		if (xclk->lookup)
>>   			clkdev_drop(xclk->lookup);
>>   	}
>> diff --git a/drivers/media/platform/omap3isp/isp.h
>> b/drivers/media/platform/omap3isp/isp.h index cd3eff4..1498f2b 100644
>> --- a/drivers/media/platform/omap3isp/isp.h
>> +++ b/drivers/media/platform/omap3isp/isp.h
>> @@ -135,6 +135,7 @@ struct isp_xclk {
>>   	struct isp_device *isp;
>>   	struct clk_hw hw;
>>   	struct clk_lookup *lookup;
>> +	struct clk *clk;
>>   	enum isp_xclk_id id;
>>
>>   	spinlock_t lock;	/* Protects enabled and divider */

--
Regards,
Sylwester
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diff mbox

Patch

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index df3a0ec..286027a 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -290,9 +290,11 @@  static int isp_xclk_init(struct isp_device *isp)
 	struct clk_init_data init;
 	unsigned int i;

+	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i)
+		isp->xclks[i].clk = ERR_PTR(-EINVAL);
+
 	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i) {
 		struct isp_xclk *xclk = &isp->xclks[i];
-		struct clk *clk;

 		xclk->isp = isp;
 		xclk->id = i == 0 ? ISP_XCLK_A : ISP_XCLK_B;
@@ -305,10 +307,15 @@  static int isp_xclk_init(struct isp_device *isp)
 		init.num_parents = 1;

 		xclk->hw.init = &init;
-
-		clk = devm_clk_register(isp->dev, &xclk->hw);
-		if (IS_ERR(clk))
-			return PTR_ERR(clk);
+		/*
+		 * The first argument is NULL in order to avoid circular
+		 * reference, as this driver takes reference on the
+		 * sensor subdevice modules and the sensors would take
+		 * reference on this module through clk_get().
+		 */
+		xclk->clk = clk_register(NULL, &xclk->hw);
+		if (IS_ERR(xclk->clk))
+			return PTR_ERR(xclk->clk);

 		if (pdata->xclks[i].con_id == NULL &&
 		    pdata->xclks[i].dev_id == NULL)
@@ -320,7 +327,7 @@  static int isp_xclk_init(struct isp_device *isp)

 		xclk->lookup->con_id = pdata->xclks[i].con_id;
 		xclk->lookup->dev_id = pdata->xclks[i].dev_id;
-		xclk->lookup->clk = clk;
+		xclk->lookup->clk = xclk->clk;

 		clkdev_add(xclk->lookup);
 	}
@@ -335,6 +342,9 @@  static void isp_xclk_cleanup(struct isp_device *isp)
 	for (i = 0; i < ARRAY_SIZE(isp->xclks); ++i) {
 		struct isp_xclk *xclk = &isp->xclks[i];

+		if (!IS_ERR(xclk->clk))
+			clk_unregister(xclk->clk);
+
 		if (xclk->lookup)
 			clkdev_drop(xclk->lookup);
 	}
diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
index cd3eff4..1498f2b 100644
--- a/drivers/media/platform/omap3isp/isp.h
+++ b/drivers/media/platform/omap3isp/isp.h
@@ -135,6 +135,7 @@  struct isp_xclk {
 	struct isp_device *isp;
 	struct clk_hw hw;
 	struct clk_lookup *lookup;
+	struct clk *clk;
 	enum isp_xclk_id id;

 	spinlock_t lock;	/* Protects enabled and divider */