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Commit 7a9ed11b authored by Saravana Kannan's avatar Saravana Kannan
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ANDROID: GKI: clk: Add support for clock providers with sync state 



Clock providers whose drivers have sync_state() implemented will disable
their clocks once all their consumers have probed. So during
late_initcall_sync(), don't disable unused clocks of these clock
providers.

Also, provide a clk_sync_state() API that clock providers can use to
disable all their unused clocks once they get their sync_state()
callback.

Bug: 144066914
Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Change-Id: Id01bfc15347812faa19802463c088db162c7d117
parent 82e8a5fb

drivers/clk/clk.c

+66 −0
Original line number Diff line number Diff line
@@ -72,6 +72,8 @@ struct clk_core { 
	unsigned long		flags;

	bool			orphan;

	bool			rpm_enabled;

	bool			need_sync;

	bool			boot_enabled;

	unsigned int		enable_count;

	unsigned int		prepare_count;

	unsigned int		protect_count;
@@ -1300,6 +1302,38 @@ static int clk_disable_unused(void) 
}

late_initcall_sync(clk_disable_unused);



static void clk_unprepare_disable_dev_subtree(struct clk_core *core,

					      struct device *dev)

{

	struct clk_core *child;



	lockdep_assert_held(&prepare_lock);



	hlist_for_each_entry(child, &core->children, child_node)

		clk_unprepare_disable_dev_subtree(child, dev);



	if (core->dev != dev || !core->need_sync)

		return;



	clk_core_disable_unprepare(core);

}



void clk_sync_state(struct device *dev)

{

	struct clk_core *core;



	clk_prepare_lock();



	hlist_for_each_entry(core, &clk_root_list, child_node)

		clk_unprepare_disable_dev_subtree(core, dev);



	hlist_for_each_entry(core, &clk_orphan_list, child_node)

		clk_unprepare_disable_dev_subtree(core, dev);



	clk_prepare_unlock();

}

EXPORT_SYMBOL_GPL(clk_sync_state);



static int clk_core_determine_round_nolock(struct clk_core *core,

					   struct clk_rate_request *req)

{
@@ -1674,6 +1708,33 @@ static int clk_fetch_parent_index(struct clk_core *core, 
	return i;

}



static void clk_core_hold_state(struct clk_core *core)

{

	if (core->need_sync || !core->boot_enabled)

		return;



	if (core->orphan || !dev_has_sync_state(core->dev))

		return;



	if (core->flags & CLK_DONT_HOLD_STATE)

		return;



	core->need_sync = !clk_core_prepare_enable(core);

}



static void __clk_core_update_orphan_hold_state(struct clk_core *core)

{

	struct clk_core *child;



	if (core->orphan)

		return;



	clk_core_hold_state(core);



	hlist_for_each_entry(child, &core->children, child_node)

		__clk_core_update_orphan_hold_state(child);

}



/*

 * Update the orphan status of @core and all its children.

 */
@@ -3384,6 +3445,8 @@ static int __clk_core_init(struct clk_core *core) 
		rate = 0;

	core->rate = core->req_rate = rate;



	core->boot_enabled = clk_core_is_enabled(core);



	/*

	 * Enable CLK_IS_CRITICAL clocks so newly added critical clocks

	 * don't get accidentally disabled when walking the orphan tree and
@@ -3399,6 +3462,8 @@ static int __clk_core_init(struct clk_core *core) 
		clk_enable_unlock(flags);

	}



	clk_core_hold_state(core);



	/*

	 * walk the list of orphan clocks and reparent any that newly finds a

	 * parent.
@@ -3418,6 +3483,7 @@ static int __clk_core_init(struct clk_core *core) 
			__clk_set_parent_after(orphan, parent, NULL);

			__clk_recalc_accuracies(orphan);

			__clk_recalc_rates(orphan, 0);

			__clk_core_update_orphan_hold_state(orphan);

		}

	}

include/linux/clk-provider.h

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#define CLK_OPS_PARENT_ENABLE	BIT(12)

/* duty cycle call may be forwarded to the parent clock */

#define CLK_DUTY_CYCLE_PARENT	BIT(13)

#define CLK_DONT_HOLD_STATE	BIT(14) /* Don't hold state */



struct clk;

struct clk_hw;
@@ -815,6 +816,7 @@ void devm_clk_unregister(struct device *dev, struct clk *clk); 


void clk_hw_unregister(struct clk_hw *hw);

void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);

void clk_sync_state(struct device *dev);



/* helper functions */

const char *__clk_get_name(const struct clk *clk);