[PATCH v7 1/5] omap3isp: Modify clocks registration to avoid circular references
From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
Date: 2013-10-29 22:28:15
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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.
quoted hunk ↗ jump to hunk
--- 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.cb/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.hb/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