diff mbox

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

Message ID 1386177127-2894-2-git-send-email-s.nawrocki@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sylwester Nawrocki/Kernel \(PLT\) /SRPOL/Staff Engineer/Samsung Electronics Dec. 4, 2013, 5:12 p.m. UTC 
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 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.

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

Comments

Sylwester Nawrocki Dec. 16, 2013, 10:14 p.m. UTC | #1 
Hi Mike,

Laurent has already taken this patch into his tree, could you apply
the remaining ones to your clk tree so this series has enough exposure
in -next ?

Thanks,
Sylwester
Mike Turquette Dec. 19, 2013, 8:07 a.m. UTC | #2 
Quoting Sylwester Nawrocki (2013-12-16 14:14:37)
> Hi Mike,
> 
> Laurent has already taken this patch into his tree, could you apply
> the remaining ones to your clk tree so this series has enough exposure
> in -next ?

I've taken this in privately to do a little testing. If all goes well
then I'll push it out to clk-next very soon.

Thanks!
Mike

> 
> Thanks,
> Sylwester
Mike Turquette Dec. 31, 2013, 7:37 p.m. UTC | #3 
Quoting Mike Turquette (2013-12-19 00:07:29)
> Quoting Sylwester Nawrocki (2013-12-16 14:14:37)
> > Hi Mike,
> > 
> > Laurent has already taken this patch into his tree, could you apply
> > the remaining ones to your clk tree so this series has enough exposure
> > in -next ?
> 
> I've taken this in privately to do a little testing. If all goes well
> then I'll push it out to clk-next very soon.

This is in clk-next now. Hopefully nothing bad will happen when it hits
linux-next ;-)

Regards,
Mike

> 
> Thanks!
> Mike
> 
> > 
> > Thanks,
> > Sylwester
Sylwester Nawrocki Dec. 31, 2013, 9:23 p.m. UTC | #4 
On 12/31/2013 08:37 PM, Mike Turquette wrote:
> Quoting Mike Turquette (2013-12-19 00:07:29)
>> Quoting Sylwester Nawrocki (2013-12-16 14:14:37)
>>> Hi Mike,
>>>
>>> Laurent has already taken this patch into his tree, could you apply
>>> the remaining ones to your clk tree so this series has enough exposure
>>> in -next ?
>>
>> I've taken this in privately to do a little testing. If all goes well
>> then I'll push it out to clk-next very soon.
>
> This is in clk-next now. Hopefully nothing bad will happen when it hits
> linux-next ;-)

Thanks Mike. Yes, fingers crossed ;)

Regards,
Sylwester
diff mbox

Patch

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index 1c36080..5910662 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 ce65d3a..d1e857e 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 */