Messages in this thread | | | From | Laurent Pinchart <> | Subject | Re: [PATCH v7 1/5] omap3isp: Modify clocks registration to avoid circular references | Date | Tue, 29 Oct 2013 23:28:37 +0100 |
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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 */
-- Regards,
Laurent Pinchart
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