diff mbox

[v3,01/10] clk: take the prepare lock out of clk_core_set_parent

Message ID 20170612194438.12298-2-jbrunet@baylibre.com (mailing list archive)
State Changes Requested
Delegated to: Stephen Boyd
Headers show

Commit Message

Jerome Brunet June 12, 2017, 7:44 p.m. UTC 
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.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/clk/clk.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

Comments

Stephen Boyd July 12, 2017, 1:21 a.m. UTC | #1 
On 06/12, Jerome Brunet wrote:
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index fc58c52a26b4..f5c371532509 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1787,7 +1787,8 @@ 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;
> @@ -1796,23 +1797,16 @@ static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
>  	if (!core)
>  		return 0;
>  
> -	/* prevent racing with updates to the clock topology */
> -	clk_prepare_lock();

Please add a lockdep assertion as we have in other places in this
file so that callers can't mess up calling the nolock function
without the lock held themselves.

> -
>  	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 = -ENOSYS;
> -		goto out;
> -	}
> +	if ((core->num_parents > 1) && (!core->ops->set_parent))

Nitpick: drop the extra parenthesis here.

> +		return -ENOSYS;
>  
>  	/* 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) {
> @@ -1820,8 +1814,7 @@ 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;
>  	}
diff mbox

Patch

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index fc58c52a26b4..f5c371532509 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1787,7 +1787,8 @@  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;
@@ -1796,23 +1797,16 @@  static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
 	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 = -ENOSYS;
-		goto out;
-	}
+	if ((core->num_parents > 1) && (!core->ops->set_parent))
+		return -ENOSYS;
 
 	/* 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) {
@@ -1820,8 +1814,7 @@  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;
 	}
@@ -1831,7 +1824,7 @@  static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
 
 	/* abort if a driver objects */
 	if (ret & NOTIFY_STOP_MASK)
-		goto out;
+		return ret;
 
 	/* do the re-parent */
 	ret = __clk_set_parent(core, parent, p_index);
@@ -1844,9 +1837,6 @@  static int clk_core_set_parent(struct clk_core *core, struct clk_core *parent)
 		__clk_recalc_accuracies(core);
 	}
 
-out:
-	clk_prepare_unlock();
-
 	return ret;
 }
 
@@ -1869,10 +1859,17 @@  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);
 
@@ -2753,7 +2750,7 @@  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);