[RESEND,v7,1/5] omap3isp: Modify clocks registration to avoid circular references
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 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
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
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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
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@@ -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);
}
@@ -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 */