1 files changed, 94 insertions, 43 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8de6a22498e7..07a27b65b773 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -37,7 +37,7 @@ static HLIST_HEAD(clk_root_list);
 static HLIST_HEAD(clk_orphan_list);
 static LIST_HEAD(clk_notifier_list);
 
-static struct hlist_head *all_lists[] = {
+static const struct hlist_head *all_lists[] = {
 	&clk_root_list,
 	&clk_orphan_list,
 	NULL,
@@ -632,6 +632,24 @@ static void clk_core_get_boundaries(struct clk_core *core,
 		*max_rate = min(*max_rate, clk_user->max_rate);
 }
 
+static bool clk_core_check_boundaries(struct clk_core *core,
+				      unsigned long min_rate,
+				      unsigned long max_rate)
+{
+	struct clk *user;
+
+	lockdep_assert_held(&prepare_lock);
+
+	if (min_rate > core->max_rate || max_rate < core->min_rate)
+		return false;
+
+	hlist_for_each_entry(user, &core->clks, clks_node)
+		if (min_rate > user->max_rate || max_rate < user->min_rate)
+			return false;
+
+	return true;
+}
+
 void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
 			   unsigned long max_rate)
 {
@@ -1330,6 +1348,8 @@ static int clk_core_determine_round_nolock(struct clk_core *core,
 	if (!core)
 		return 0;
 
+	req->rate = clamp(req->rate, req->min_rate, req->max_rate);
+
 	/*
 	 * At this point, core protection will be disabled
 	 * - if the provider is not protected at all
@@ -2312,19 +2332,15 @@ int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
 }
 EXPORT_SYMBOL_GPL(clk_set_rate_exclusive);
 
-/**
- * clk_set_rate_range - set a rate range for a clock source
- * @clk: clock source
- * @min: desired minimum clock rate in Hz, inclusive
- * @max: desired maximum clock rate in Hz, inclusive
- *
- * Returns success (0) or negative errno.
- */
-int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
+static int clk_set_rate_range_nolock(struct clk *clk,
+				     unsigned long min,
+				     unsigned long max)
 {
 	int ret = 0;
 	unsigned long old_min, old_max, rate;
 
+	lockdep_assert_held(&prepare_lock);
+
 	if (!clk)
 		return 0;
 
@@ -2337,8 +2353,6 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
 		return -EINVAL;
 	}
 
-	clk_prepare_lock();
-
 	if (clk->exclusive_count)
 		clk_core_rate_unprotect(clk->core);
 
@@ -2348,37 +2362,62 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
 	clk->min_rate = min;
 	clk->max_rate = max;
 
-	rate = clk_core_get_rate_nolock(clk->core);
-	if (rate < min || rate > max) {
-		/*
-		 * FIXME:
-		 * We are in bit of trouble here, current rate is outside the
-		 * the requested range. We are going try to request appropriate
-		 * range boundary but there is a catch. It may fail for the
-		 * usual reason (clock broken, clock protected, etc) but also
-		 * because:
-		 * - round_rate() was not favorable and fell on the wrong
-		 *   side of the boundary
-		 * - the determine_rate() callback does not really check for
-		 *   this corner case when determining the rate
-		 */
-
-		if (rate < min)
-			rate = min;
-		else
-			rate = max;
+	if (!clk_core_check_boundaries(clk->core, min, max)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
-		ret = clk_core_set_rate_nolock(clk->core, rate);
-		if (ret) {
-			/* rollback the changes */
-			clk->min_rate = old_min;
-			clk->max_rate = old_max;
-		}
+	/*
+	 * Since the boundaries have been changed, let's give the
+	 * opportunity to the provider to adjust the clock rate based on
+	 * the new boundaries.
+	 *
+	 * We also need to handle the case where the clock is currently
+	 * outside of the boundaries. Clamping the last requested rate
+	 * to the current minimum and maximum will also handle this.
+	 *
+	 * FIXME:
+	 * There is a catch. It may fail for the usual reason (clock
+	 * broken, clock protected, etc) but also because:
+	 * - round_rate() was not favorable and fell on the wrong
+	 *   side of the boundary
+	 * - the determine_rate() callback does not really check for
+	 *   this corner case when determining the rate
+	 */
+	rate = clamp(clk->core->req_rate, min, max);
+	ret = clk_core_set_rate_nolock(clk->core, rate);
+	if (ret) {
+		/* rollback the changes */
+		clk->min_rate = old_min;
+		clk->max_rate = old_max;
 	}
 
+out:
 	if (clk->exclusive_count)
 		clk_core_rate_protect(clk->core);
 
+	return ret;
+}
+
+/**
+ * clk_set_rate_range - set a rate range for a clock source
+ * @clk: clock source
+ * @min: desired minimum clock rate in Hz, inclusive
+ * @max: desired maximum clock rate in Hz, inclusive
+ *
+ * Return: 0 for success or negative errno on failure.
+ */
+int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
+{
+	int ret;
+
+	if (!clk)
+		return 0;
+
+	clk_prepare_lock();
+
+	ret = clk_set_rate_range_nolock(clk, min, max);
+
 	clk_prepare_unlock();
 
 	return ret;
@@ -3456,6 +3495,19 @@ static void clk_core_reparent_orphans_nolock(void)
 			__clk_set_parent_after(orphan, parent, NULL);
 			__clk_recalc_accuracies(orphan);
 			__clk_recalc_rates(orphan, 0);
+
+			/*
+			 * __clk_init_parent() will set the initial req_rate to
+			 * 0 if the clock doesn't have clk_ops::recalc_rate and
+			 * is an orphan when it's registered.
+			 *
+			 * 'req_rate' is used by clk_set_rate_range() and
+			 * clk_put() to trigger a clk_set_rate() call whenever
+			 * the boundaries are modified. Let's make sure
+			 * 'req_rate' is set to something non-zero so that
+			 * clk_set_rate_range() doesn't drop the frequency.
+			 */
+			orphan->req_rate = orphan->rate;
 		}
 	}
 }
@@ -3773,8 +3825,9 @@ struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
 struct clk *clk_hw_get_clk(struct clk_hw *hw, const char *con_id)
 {
 	struct device *dev = hw->core->dev;
+	const char *name = dev ? dev_name(dev) : NULL;
 
-	return clk_hw_create_clk(dev, hw, dev_name(dev), con_id);
+	return clk_hw_create_clk(dev, hw, name, con_id);
 }
 EXPORT_SYMBOL(clk_hw_get_clk);
 
@@ -4079,7 +4132,7 @@ static const struct clk_ops clk_nodrv_ops = {
 };
 
 static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
-						struct clk_core *target)
+						const struct clk_core *target)
 {
 	int i;
 	struct clk_core *child;
@@ -4095,7 +4148,7 @@ static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
 /* Remove this clk from all parent caches */
 static void clk_core_evict_parent_cache(struct clk_core *core)
 {
-	struct hlist_head **lists;
+	const struct hlist_head **lists;
 	struct clk_core *root;
 
 	lockdep_assert_held(&prepare_lock);
@@ -4366,9 +4419,7 @@ void __clk_put(struct clk *clk)
 	}
 
 	hlist_del(&clk->clks_node);
-	if (clk->min_rate > clk->core->req_rate ||
-	    clk->max_rate < clk->core->req_rate)
-		clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
+	clk_set_rate_range_nolock(clk, 0, ULONG_MAX);
 
 	owner = clk->core->owner;
 	kref_put(&clk->core->ref, __clk_release);