[RFC PATCH] cpufreq: Introduce macros for cpufreq_frequency_table iteration

[Stratos Karafotis <stratosk@semaphore.gr>]

This patch intoduces 2 macros which can be used for iteration
over cpufreq_frequency_table:

- cpufreq_for_each_entry: iterate over each entry of the table
- cpufreq_for_each_valid_entry: iterate over each entry of the
table that contains a valid frequency.

It should have no functional changes.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
---

I found about 20 occurrences in various drivers that these macros
can be used. I will proceed with the necessary changes if you
approve something like this.

Thanks in advance for your time,
Stratos Karafotis.
---

 drivers/cpufreq/freq_table.c | 54 ++++++++++++++++++++------------------------
 include/linux/cpufreq.h      | 29 ++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 30 deletions(-)

diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 08e7bbc..19bf0c4 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -21,22 +21,18 @@
 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 				    struct cpufreq_frequency_table *table)
 {
+	struct cpufreq_frequency_table *pos;
 	unsigned int min_freq = ~0;
 	unsigned int max_freq = 0;
-	unsigned int i;
 
-	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
-		unsigned int freq = table[i].frequency;
-		if (freq == CPUFREQ_ENTRY_INVALID) {
-			pr_debug("table entry %u is invalid, skipping\n", i);
+	cpufreq_for_each_valid_entry(pos, table) {
+		unsigned int freq = pos->frequency;
 
-			continue;
-		}
 		if (!cpufreq_boost_enabled()
-		    && (table[i].flags & CPUFREQ_BOOST_FREQ))
+		    && (pos->flags & CPUFREQ_BOOST_FREQ))
 			continue;
 
-		pr_debug("table entry %u: %u kHz\n", i, freq);
+		pr_debug("table entry %lu: %u kHz\n", pos - table, freq);
 		if (freq < min_freq)
 			min_freq = freq;
 		if (freq > max_freq)
@@ -57,7 +53,8 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_cpuinfo);
 int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 				   struct cpufreq_frequency_table *table)
 {
-	unsigned int next_larger = ~0, freq, i = 0;
+	struct cpufreq_frequency_table *pos;
+	unsigned int next_larger = ~0, freq;
 	bool found = false;
 
 	pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
@@ -65,9 +62,9 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 
 	cpufreq_verify_within_cpu_limits(policy);
 
-	for (; freq = table[i].frequency, freq != CPUFREQ_TABLE_END; i++) {
-		if (freq == CPUFREQ_ENTRY_INVALID)
-			continue;
+	cpufreq_for_each_valid_entry(pos, table) {
+		freq = pos->frequency;
+
 		if ((freq >= policy->min) && (freq <= policy->max)) {
 			found = true;
 			break;
@@ -118,7 +115,8 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 		.driver_data = ~0,
 		.frequency = 0,
 	};
-	unsigned int i;
+	struct cpufreq_frequency_table *pos;
+	unsigned int i = 0;
 
 	pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
 					target_freq, relation, policy->cpu);
@@ -132,10 +130,10 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 		break;
 	}
 
-	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
-		unsigned int freq = table[i].frequency;
-		if (freq == CPUFREQ_ENTRY_INVALID)
-			continue;
+	cpufreq_for_each_valid_entry(pos, table) {
+		unsigned int freq = pos->frequency;
+
+		i = pos - table;
 		if ((freq < policy->min) || (freq > policy->max))
 			continue;
 		switch (relation) {
@@ -184,8 +182,7 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
 		unsigned int freq)
 {
-	struct cpufreq_frequency_table *table;
-	int i;
+	struct cpufreq_frequency_table *pos, *table;
 
 	table = cpufreq_frequency_get_table(policy->cpu);
 	if (unlikely(!table)) {
@@ -193,9 +190,9 @@ int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
 		return -ENOENT;
 	}
 
-	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
-		if (table[i].frequency == freq)
-			return i;
+	cpufreq_for_each_entry(pos, table) {
+		if (pos->frequency == freq)
+			return pos - table;
 	}
 
 	return -EINVAL;
@@ -208,16 +205,13 @@ EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index);
 static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf,
 				    bool show_boost)
 {
-	unsigned int i = 0;
 	ssize_t count = 0;
-	struct cpufreq_frequency_table *table = policy->freq_table;
+	struct cpufreq_frequency_table *pos, *table = policy->freq_table;
 
 	if (!table)
 		return -ENODEV;
 
-	for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) {
-		if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
-			continue;
+	cpufreq_for_each_valid_entry(pos, table) {
 		/*
 		 * show_boost = true and driver_data = BOOST freq
 		 * display BOOST freqs
@@ -229,10 +223,10 @@ static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf,
 		 * show_boost = false and driver_data != BOOST freq
 		 * display NON BOOST freqs
 		 */
-		if (show_boost ^ (table[i].flags & CPUFREQ_BOOST_FREQ))
+		if (show_boost ^ (pos->flags & CPUFREQ_BOOST_FREQ))
 			continue;
 
-		count += sprintf(&buf[count], "%d ", table[i].frequency);
+		count += sprintf(&buf[count], "%d ", pos->frequency);
 	}
 	count += sprintf(&buf[count], "\n");
 
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 5ae5100..1c221c8 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -468,6 +468,35 @@ struct cpufreq_frequency_table {
 				    * order */
 };
 
+static inline bool validate_entry(struct cpufreq_frequency_table *pos)
+{
+	while (pos->frequency != CPUFREQ_TABLE_END)
+		if (pos->frequency == CPUFREQ_ENTRY_INVALID)
+			pos++;
+		else
+			return true;
+	return false;
+}
+
+/*
+ * cpufreq_for_each_entry -	iterate over a cpufreq_frequency_table
+ * @pos:	the cpufreq_frequency_table * to use as a loop cursor.
+ * @table:	the cpufreq_frequency_table * to iterate over.
+ */
+
+#define cpufreq_for_each_entry(pos, table)	\
+	for (pos = table; pos->frequency != CPUFREQ_TABLE_END; pos++)
+
+/*
+ * cpufreq_for_each_valid_entry -     iterate over a cpufreq_frequency_table
+ *	exluding CPUFREQ_ENTRY_INVALID frequencies.
+ * @pos:        the cpufreq_frequency_table * to use as a loop cursor.
+ * @table:      the cpufreq_frequency_table * to iterate over.
+ */
+
+#define cpufreq_for_each_valid_entry(pos, table)	\
+	for (pos = table; validate_entry(pos); pos++)
+
 int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 				    struct cpufreq_frequency_table *table);
 
-- 
1.9.0