cpufreq: Handle sorted frequency tables more efficiently

cpufreq drivers aren't required to provide a sorted frequency table
today, and even the ones which provide a sorted table aren't handled
efficiently by cpufreq core.

This patch adds infrastructure to verify if the freq-table provided by
the drivers is sorted or not, and use efficient helpers if they are
sorted.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index eac8bcb..3bbbf9e 100644 (file)
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -113,9 +113,9 @@ int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy)
 }
 EXPORT_SYMBOL_GPL(cpufreq_generic_frequency_table_verify);
 
-int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
-                                   unsigned int target_freq,
-                                   unsigned int relation)
+int cpufreq_table_index_unsorted(struct cpufreq_policy *policy,
+                                unsigned int target_freq,
+                                unsigned int relation)
 {
        struct cpufreq_frequency_table optimal = {
                .driver_data = ~0,
@@ -205,7 +205,7 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
                 table[index].frequency);
        return index;
 }
-EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
+EXPORT_SYMBOL_GPL(cpufreq_table_index_unsorted);
 
 int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
                unsigned int freq)
@@ -297,15 +297,72 @@ struct freq_attr *cpufreq_generic_attr[] = {
 };
 EXPORT_SYMBOL_GPL(cpufreq_generic_attr);
 
+static int set_freq_table_sorted(struct cpufreq_policy *policy)
+{
+       struct cpufreq_frequency_table *pos, *table = policy->freq_table;
+       struct cpufreq_frequency_table *prev = NULL;
+       int ascending = 0;
+
+       policy->freq_table_sorted = CPUFREQ_TABLE_UNSORTED;
+
+       cpufreq_for_each_valid_entry(pos, table) {
+               if (!prev) {
+                       prev = pos;
+                       continue;
+               }
+
+               if (pos->frequency == prev->frequency) {
+                       pr_warn("Duplicate freq-table entries: %u\n",
+                               pos->frequency);
+                       return -EINVAL;
+               }
+
+               /* Frequency increased from prev to pos */
+               if (pos->frequency > prev->frequency) {
+                       /* But frequency was decreasing earlier */
+                       if (ascending < 0) {
+                               pr_debug("Freq table is unsorted\n");
+                               return 0;
+                       }
+
+                       ascending++;
+               } else {
+                       /* Frequency decreased from prev to pos */
+
+                       /* But frequency was increasing earlier */
+                       if (ascending > 0) {
+                               pr_debug("Freq table is unsorted\n");
+                               return 0;
+                       }
+
+                       ascending--;
+               }
+
+               prev = pos;
+       }
+
+       if (ascending > 0)
+               policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_ASCENDING;
+       else
+               policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_DESCENDING;
+
+       pr_debug("Freq table is sorted in %s order\n",
+                ascending > 0 ? "ascending" : "descending");
+
+       return 0;
+}
+
 int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
                                      struct cpufreq_frequency_table *table)
 {
-       int ret = cpufreq_frequency_table_cpuinfo(policy, table);
+       int ret;
 
-       if (!ret)
-               policy->freq_table = table;
+       ret = cpufreq_frequency_table_cpuinfo(policy, table);
+       if (ret)
+               return ret;
 
-       return ret;
+       policy->freq_table = table;
+       return set_freq_table_sorted(policy);
 }
 EXPORT_SYMBOL_GPL(cpufreq_table_validate_and_show);
 

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index c378776..c6410b1 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -36,6 +36,12 @@
 
 struct cpufreq_governor;
 
+enum cpufreq_table_sorting {
+       CPUFREQ_TABLE_UNSORTED,
+       CPUFREQ_TABLE_SORTED_ASCENDING,
+       CPUFREQ_TABLE_SORTED_DESCENDING
+};
+
 struct cpufreq_freqs {
        unsigned int cpu;       /* cpu nr */
        unsigned int old;
@@ -87,6 +93,7 @@ struct cpufreq_policy {
 
        struct cpufreq_user_policy user_policy;
        struct cpufreq_frequency_table  *freq_table;
+       enum cpufreq_table_sorting freq_table_sorted;
 
        struct list_head        policy_list;
        struct kobject          kobj;
@@ -597,9 +604,9 @@ int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
                                   struct cpufreq_frequency_table *table);
 int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy);
 
-int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
-                                  unsigned int target_freq,
-                                  unsigned int relation);
+int cpufreq_table_index_unsorted(struct cpufreq_policy *policy,
+                                unsigned int target_freq,
+                                unsigned int relation);
 int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
                unsigned int freq);
 
@@ -610,6 +617,227 @@ int cpufreq_boost_trigger_state(int state);
 int cpufreq_boost_enabled(void);
 int cpufreq_enable_boost_support(void);
 bool policy_has_boost_freq(struct cpufreq_policy *policy);
+
+/* Find lowest freq at or above target in a table in ascending order */
+static inline int cpufreq_table_find_index_al(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq >= target_freq)
+                       return i;
+
+               best = i;
+       }
+
+       return best;
+}
+
+/* Find lowest freq at or above target in a table in descending order */
+static inline int cpufreq_table_find_index_dl(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq == target_freq)
+                       return i;
+
+               if (freq > target_freq) {
+                       best = i;
+                       continue;
+               }
+
+               /* No freq found above target_freq */
+               if (best == -1)
+                       return i;
+
+               return best;
+       }
+
+       return best;
+}
+
+/* Works only on sorted freq-tables */
+static inline int cpufreq_table_find_index_l(struct cpufreq_policy *policy,
+                                            unsigned int target_freq)
+{
+       target_freq = clamp_val(target_freq, policy->min, policy->max);
+
+       if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
+               return cpufreq_table_find_index_al(policy, target_freq);
+       else
+               return cpufreq_table_find_index_dl(policy, target_freq);
+}
+
+/* Find highest freq at or below target in a table in ascending order */
+static inline int cpufreq_table_find_index_ah(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq == target_freq)
+                       return i;
+
+               if (freq < target_freq) {
+                       best = i;
+                       continue;
+               }
+
+               /* No freq found below target_freq */
+               if (best == -1)
+                       return i;
+
+               return best;
+       }
+
+       return best;
+}
+
+/* Find highest freq at or below target in a table in descending order */
+static inline int cpufreq_table_find_index_dh(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq <= target_freq)
+                       return i;
+
+               best = i;
+       }
+
+       return best;
+}
+
+/* Works only on sorted freq-tables */
+static inline int cpufreq_table_find_index_h(struct cpufreq_policy *policy,
+                                            unsigned int target_freq)
+{
+       target_freq = clamp_val(target_freq, policy->min, policy->max);
+
+       if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
+               return cpufreq_table_find_index_ah(policy, target_freq);
+       else
+               return cpufreq_table_find_index_dh(policy, target_freq);
+}
+
+/* Find closest freq to target in a table in ascending order */
+static inline int cpufreq_table_find_index_ac(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq == target_freq)
+                       return i;
+
+               if (freq < target_freq) {
+                       best = i;
+                       continue;
+               }
+
+               /* No freq found below target_freq */
+               if (best == -1)
+                       return i;
+
+               /* Choose the closest freq */
+               if (target_freq - table[best].frequency > freq - target_freq)
+                       return i;
+
+               return best;
+       }
+
+       return best;
+}
+
+/* Find closest freq to target in a table in descending order */
+static inline int cpufreq_table_find_index_dc(struct cpufreq_policy *policy,
+                                             unsigned int target_freq)
+{
+       struct cpufreq_frequency_table *table = policy->freq_table;
+       unsigned int freq;
+       int i, best = -1;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               freq = table[i].frequency;
+
+               if (freq == target_freq)
+                       return i;
+
+               if (freq > target_freq) {
+                       best = i;
+                       continue;
+               }
+
+               /* No freq found above target_freq */
+               if (best == -1)
+                       return i;
+
+               /* Choose the closest freq */
+               if (table[best].frequency - target_freq > target_freq - freq)
+                       return i;
+
+               return best;
+       }
+
+       return best;
+}
+
+/* Works only on sorted freq-tables */
+static inline int cpufreq_table_find_index_c(struct cpufreq_policy *policy,
+                                            unsigned int target_freq)
+{
+       target_freq = clamp_val(target_freq, policy->min, policy->max);
+
+       if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
+               return cpufreq_table_find_index_ac(policy, target_freq);
+       else
+               return cpufreq_table_find_index_dc(policy, target_freq);
+}
+
+static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
+                                                unsigned int target_freq,
+                                                unsigned int relation)
+{
+       if (unlikely(policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED))
+               return cpufreq_table_index_unsorted(policy, target_freq,
+                                                   relation);
+
+       switch (relation) {
+       case CPUFREQ_RELATION_L:
+               return cpufreq_table_find_index_l(policy, target_freq);
+       case CPUFREQ_RELATION_H:
+               return cpufreq_table_find_index_h(policy, target_freq);
+       case CPUFREQ_RELATION_C:
+               return cpufreq_table_find_index_c(policy, target_freq);
+       default:
+               pr_err("%s: Invalid relation: %d\n", __func__, relation);
+               return -EINVAL;
+       }
+}
 #else
 static inline int cpufreq_boost_trigger_state(int state)
 {