arm: ux500: updated clk_set_rate

This patch updates clk_set_rate so that it only works for
disabled clocks, as well as making sure that it doesn't
interfere with itself at another depth of the clock tree.

ST Ericsson ID: 343004, 359227
ST Ericsson FOSS-OUT ID: trivial

Change-Id: I9dbf32f73e89f8f248e51b15097b50975b951a73
Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/32967
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

2 files changed, 53 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/clock.c b/arch/arm/mach-ux500/clock.c
index 108014ea55b..13aaaf7e388 100644
--- a/arch/arm/mach-ux500/clock.c
+++ b/arch/arm/mach-ux500/clock.c
@@ -213,6 +213,36 @@ long clk_round_rate_rec(struct clk *clk, unsigned long rate)
 	return rounded_rate;
 }
 
+static void lock_parent_rate(struct clk *clk)
+{
+	unsigned long flags;
+
+	if (clk->parent == NULL)
+		return;
+
+	__clk_lock(clk->parent, clk->mutex, &flags);
+
+	lock_parent_rate(clk->parent);
+	clk->parent->rate_locked++;
+
+	__clk_unlock(clk->parent, clk->mutex, flags);
+}
+
+static void unlock_parent_rate(struct clk *clk)
+{
+	unsigned long flags;
+
+	if (clk->parent == NULL)
+		return;
+
+	__clk_lock(clk->parent, clk->mutex, &flags);
+
+	unlock_parent_rate(clk->parent);
+	clk->parent->rate_locked--;
+
+	__clk_unlock(clk->parent, clk->mutex, flags);
+}
+
 int clk_set_rate(struct clk *clk, unsigned long rate)
 {
 	int err;
@@ -223,8 +253,20 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 
 	__clk_lock(clk, NO_LOCK, &flags);
 
+	if (clk->enabled) {
+		err = -EBUSY;
+		goto unlock_and_return;
+	}
+	if (clk->rate_locked) {
+		err = -EAGAIN;
+		goto unlock_and_return;
+	}
+
+	lock_parent_rate(clk);
 	err =  __clk_set_rate(clk, rate);
+	unlock_parent_rate(clk);
 
+unlock_and_return:
 	__clk_unlock(clk, NO_LOCK, flags);
 
 	return err;
@@ -241,8 +283,17 @@ int clk_set_rate_rec(struct clk *clk, unsigned long rate)
 
 	__clk_lock(clk->parent, clk->mutex, &flags);
 
+	if (clk->parent->enabled) {
+		err = -EBUSY;
+		goto unlock_and_return;
+	}
+	if (clk->parent->rate_locked != 1) {
+		err = -EAGAIN;
+		goto unlock_and_return;
+	}
 	err = __clk_set_rate(clk->parent, rate);
 
+unlock_and_return:
 	__clk_unlock(clk->parent, clk->mutex, flags);
 
 	return err;
diff --git a/arch/arm/mach-ux500/clock.h b/arch/arm/mach-ux500/clock.h
index 39d8a61d79b..8bca502d968 100644
--- a/arch/arm/mach-ux500/clock.h
+++ b/arch/arm/mach-ux500/clock.h
@@ -18,6 +18,7 @@
  * @mutex:	The mutex to lock when operating on the clock. %NULL means that
  *		the common clock spinlock will be used.
  * @enabled:	A reference counter of the enable requests for the clock.
+ * @rate_locked: A rate lock counter used by clk_set_rate().
  * @opp100:	A flag saying whether the clock is requested to run at the
  *		OPP 100%% frequency.
  * @rate:	The frequency of the clock. For scalable and scaling clocks,
@@ -39,6 +40,7 @@ struct clk {
 	const char *name;
 	struct mutex *mutex;
 	unsigned int enabled;
+	unsigned int rate_locked;
 	bool opp100;
 	unsigned long rate;
 	unsigned int io_base;