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Commit 91baa9ff authored by Jerome Brunet's avatar Jerome Brunet Committed by Michael Turquette
Browse files

clk: take the prepare lock out of clk_core_set_parent 



Rework set_parent core function so it can be called when the prepare lock
is already held by the caller.

This rework is done to ease the integration of the "protected" clock
functionality.

Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Tested-by: default avatarQuentin Schulz <quentin.schulz@free-electrons.com>
Tested-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: default avatarMichael Turquette <mturquette@baylibre.com>
Signed-off-by: default avatarJerome Brunet <jbrunet@baylibre.com>
Signed-off-by: default avatarMichael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20171201215200.23523-3-jbrunet@baylibre.com
parent 56e7cedd

drivers/clk/clk.c

+20 −20
Original line number Diff line number Diff line
@@ -1871,32 +1871,28 @@ bool clk_has_parent(struct clk *clk, struct clk *parent) 
}

EXPORT_SYMBOL_GPL(clk_has_parent);



static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)

static int clk_core_set_parent_nolock(struct clk_core *core,

				      struct clk_core *parent)

{

	int ret = 0;

	int p_index = 0;

	unsigned long p_rate = 0;



	lockdep_assert_held(&prepare_lock);



	if (!core)

		return 0;



	/* prevent racing with updates to the clock topology */

	clk_prepare_lock();



	if (core->parent == parent)

		goto out;

		return 0;



	/* verify ops for for multi-parent clks */

	if ((core->num_parents > 1) && (!core->ops->set_parent)) {

		ret = -EPERM;

		goto out;

	}

	if (core->num_parents > 1 && !core->ops->set_parent)

		return -EPERM;



	/* check that we are allowed to re-parent if the clock is in use */

	if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {

		ret = -EBUSY;

		goto out;

	}

	if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count)

		return -EBUSY;



	/* try finding the new parent index */

	if (parent) {
@@ -1904,15 +1900,14 @@ static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent) 
		if (p_index < 0) {

			pr_debug("%s: clk %s can not be parent of clk %s\n",

					__func__, parent->name, core->name);

			ret = p_index;

			goto out;

			return p_index;

		}

		p_rate = parent->rate;

	}



	ret = clk_pm_runtime_get(core);

	if (ret)

		goto out;

		return ret;



	/* propagate PRE_RATE_CHANGE notifications */

	ret = __clk_speculate_rates(core, p_rate);
@@ -1934,8 +1929,6 @@ static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent) 


runtime_put:

	clk_pm_runtime_put(core);

out:

	clk_prepare_unlock();



	return ret;

}
@@ -1959,10 +1952,17 @@ static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent) 
 */

int clk_set_parent(struct clk *clk, struct clk *parent)

{

	int ret;



	if (!clk)

		return 0;



	return clk_core_set_parent(clk->core, parent ? parent->core : NULL);

	clk_prepare_lock();

	ret = clk_core_set_parent_nolock(clk->core,

					 parent ? parent->core : NULL);

	clk_prepare_unlock();



	return ret;

}

EXPORT_SYMBOL_GPL(clk_set_parent);
@@ -2851,7 +2851,7 @@ void clk_unregister(struct clk *clk) 
		/* Reparent all children to the orphan list. */

		hlist_for_each_entry_safe(child, t, &clk->core->children,

					  child_node)

			clk_core_set_parent(child, NULL);

			clk_core_set_parent_nolock(child, NULL);

	}



	hlist_del_init(&clk->core->child_node);