OPP: Add generic key finding helpers and use them for freq APIs

There are three type of helpers, to find exact, ceil, and floor values,
replicated for multiple key types, freq, level, bw. And all of these
helpers share a lot of boilerplate code.

Add generic key finding helpers to reduce code redundancy.

Also update the freq finder helpers to use the new infrastructure.
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/core.c

@@ -427,6 +427,131 @@ int dev_pm_opp_get_opp_count(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
 
+/* Helpers to read keys */
+static unsigned long _read_freq(struct dev_pm_opp *opp, int index)
+{
+	return opp->rate;
+}
+
+/* Generic comparison helpers */
+static bool _compare_exact(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
+			   unsigned long opp_key, unsigned long key)
+{
+	if (opp_key == key) {
+		*opp = temp_opp;
+		return true;
+	}
+
+	return false;
+}
+
+static bool _compare_ceil(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
+			  unsigned long opp_key, unsigned long key)
+{
+	if (opp_key >= key) {
+		*opp = temp_opp;
+		return true;
+	}
+
+	return false;
+}
+
+static bool _compare_floor(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
+			   unsigned long opp_key, unsigned long key)
+{
+	if (opp_key > key)
+		return true;
+
+	*opp = temp_opp;
+	return false;
+}
+
+/* Generic key finding helpers */
+static struct dev_pm_opp *_opp_table_find_key(struct opp_table *opp_table,
+		unsigned long *key, int index, bool available,
+		unsigned long (*read)(struct dev_pm_opp *opp, int index),
+		bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
+				unsigned long opp_key, unsigned long key))
+{
+	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+	mutex_lock(&opp_table->lock);
+
+	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
+		if (temp_opp->available == available) {
+			if (compare(&opp, temp_opp, read(temp_opp, index), *key))
+				break;
+		}
+	}
+
+	/* Increment the reference count of OPP */
+	if (!IS_ERR(opp)) {
+		*key = read(opp, index);
+		dev_pm_opp_get(opp);
+	}
+
+	mutex_unlock(&opp_table->lock);
+
+	return opp;
+}
+
+static struct dev_pm_opp *
+_find_key(struct device *dev, unsigned long *key, int index, bool available,
+	  unsigned long (*read)(struct dev_pm_opp *opp, int index),
+	  bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
+			  unsigned long opp_key, unsigned long key))
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *opp;
+
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table)) {
+		dev_err(dev, "%s: OPP table not found (%ld)\n", __func__,
+			PTR_ERR(opp_table));
+		return ERR_CAST(opp_table);
+	}
+
+	opp = _opp_table_find_key(opp_table, key, index, available, read,
+				  compare);
+
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return opp;
+}
+
+static struct dev_pm_opp *_find_key_exact(struct device *dev,
+		unsigned long key, int index, bool available,
+		unsigned long (*read)(struct dev_pm_opp *opp, int index))
+{
+	/*
+	 * The value of key will be updated here, but will be ignored as the
+	 * caller doesn't need it.
+	 */
+	return _find_key(dev, &key, index, available, read, _compare_exact);
+}
+
+static struct dev_pm_opp *_opp_table_find_key_ceil(struct opp_table *opp_table,
+		unsigned long *key, int index, bool available,
+		unsigned long (*read)(struct dev_pm_opp *opp, int index))
+{
+	return _opp_table_find_key(opp_table, key, index, available, read,
+				   _compare_ceil);
+}
+
+static struct dev_pm_opp *_find_key_ceil(struct device *dev, unsigned long *key,
+		int index, bool available,
+		unsigned long (*read)(struct dev_pm_opp *opp, int index))
+{
+	return _find_key(dev, key, index, available, read, _compare_ceil);
+}
+
+static struct dev_pm_opp *_find_key_floor(struct device *dev,
+		unsigned long *key, int index, bool available,
+		unsigned long (*read)(struct dev_pm_opp *opp, int index))
+{
+	return _find_key(dev, key, index, available, read, _compare_floor);
+}
+
 /**
  * dev_pm_opp_find_freq_exact() - search for an exact frequency
  * @dev:		device for which we do this operation
@@ -451,61 +576,16 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
  * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
-					      unsigned long freq,
-					      bool available)
+		unsigned long freq, bool available)
 {
-	struct opp_table *opp_table;
-	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
-
-	opp_table = _find_opp_table(dev);
-	if (IS_ERR(opp_table)) {
-		int r = PTR_ERR(opp_table);
-
-		dev_err(dev, "%s: OPP table not found (%d)\n", __func__, r);
-		return ERR_PTR(r);
-	}
-
-	mutex_lock(&opp_table->lock);
-
-	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
-		if (temp_opp->available == available &&
-				temp_opp->rate == freq) {
-			opp = temp_opp;
-
-			/* Increment the reference count of OPP */
-			dev_pm_opp_get(opp);
-			break;
-		}
-	}
-
-	mutex_unlock(&opp_table->lock);
-	dev_pm_opp_put_opp_table(opp_table);
-
-	return opp;
+	return _find_key_exact(dev, freq, 0, available, _read_freq);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
 
 static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
 						   unsigned long *freq)
 {
-	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
-
-	mutex_lock(&opp_table->lock);
-
-	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
-		if (temp_opp->available && temp_opp->rate >= *freq) {
-			opp = temp_opp;
-			*freq = opp->rate;
-
-			/* Increment the reference count of OPP */
-			dev_pm_opp_get(opp);
-			break;
-		}
-	}
-
-	mutex_unlock(&opp_table->lock);
-
-	return opp;
+	return _opp_table_find_key_ceil(opp_table, freq, 0, true, _read_freq);
 }
 
 /**
@@ -529,23 +609,7 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
 struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 					     unsigned long *freq)
 {
-	struct opp_table *opp_table;
-	struct dev_pm_opp *opp;
-
-	if (!dev || !freq) {
-		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
-		return ERR_PTR(-EINVAL);
-	}
-
-	opp_table = _find_opp_table(dev);
-	if (IS_ERR(opp_table))
-		return ERR_CAST(opp_table);
-
-	opp = _find_freq_ceil(opp_table, freq);
-
-	dev_pm_opp_put_opp_table(opp_table);
-
-	return opp;
+	return _find_key_ceil(dev, freq, 0, true, _read_freq);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 
@@ -570,40 +634,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 					      unsigned long *freq)
 {
-	struct opp_table *opp_table;
-	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
-
-	if (!dev || !freq) {
-		dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
-		return ERR_PTR(-EINVAL);
-	}
-
-	opp_table = _find_opp_table(dev);
-	if (IS_ERR(opp_table))
-		return ERR_CAST(opp_table);
-
-	mutex_lock(&opp_table->lock);
-
-	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
-		if (temp_opp->available) {
-			/* go to the next node, before choosing prev */
-			if (temp_opp->rate > *freq)
-				break;
-			else
-				opp = temp_opp;
-		}
-	}
-
-	/* Increment the reference count of OPP */
-	if (!IS_ERR(opp))
-		dev_pm_opp_get(opp);
-	mutex_unlock(&opp_table->lock);
-	dev_pm_opp_put_opp_table(opp_table);
-
-	if (!IS_ERR(opp))
-		*freq = opp->rate;
-
-	return opp;
+	return _find_key_floor(dev, freq, 0, true, _read_freq);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);