Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq

[linux-drm-fsl-dcu.git] / drivers / cpufreq / cpufreq_conservative.c

diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 037f6bf4543c3c29b98e6401d8cb242b85a2f993..26f440ccc3fb358e9525ecabee819ae52b7afa26 100644 (file)
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -22,7 +22,7 @@
 #include <linux/types.h>
 #include <linux/fs.h>
 #include <linux/sysfs.h>
-#include <linux/sched.h>
+#include <linux/cpu.h>
 #include <linux/kmod.h>
 #include <linux/workqueue.h>
 #include <linux/jiffies.h>
@@ -43,22 +43,24 @@
  * latency of the processor. The governor will work on any processor with 
  * transition latency <= 10mS, using appropriate sampling 
  * rate.
- * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
- * this governor will not work.
+ * For CPUs with transition latency > 10mS (mostly drivers
+ * with CPUFREQ_ETERNAL), this governor will not work.
  * All times here are in uS.
  */
 static unsigned int                            def_sampling_rate;
 #define MIN_SAMPLING_RATE_RATIO                        (2)
 /* for correct statistics, we need at least 10 ticks between each measure */
-#define MIN_STAT_SAMPLING_RATE                 (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
-#define MIN_SAMPLING_RATE                      (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
+#define MIN_STAT_SAMPLING_RATE                 \
+                       (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
+#define MIN_SAMPLING_RATE                      \
+                       (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
 #define MAX_SAMPLING_RATE                      (500 * def_sampling_rate)
 #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER   (1000)
 #define DEF_SAMPLING_DOWN_FACTOR               (1)
 #define MAX_SAMPLING_DOWN_FACTOR               (10)
 #define TRANSITION_LATENCY_LIMIT               (10 * 1000)
 
-static void do_dbs_timer(void *data);
+static void do_dbs_timer(struct work_struct *work);
 
 struct cpu_dbs_info_s {
        struct cpufreq_policy   *cur_policy;
@@ -72,8 +74,16 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
 
 static unsigned int dbs_enable;        /* number of CPUs using this policy */
 
+/*
+ * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
+ * lock and dbs_mutex. cpu_hotplug lock should always be held before
+ * dbs_mutex. If any function that can potentially take cpu_hotplug lock
+ * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
+ * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
+ * is recursive for the same process. -Venki
+ */
 static DEFINE_MUTEX    (dbs_mutex);
-static DECLARE_WORK    (dbs_work, do_dbs_timer, NULL);
+static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);
 
 struct dbs_tuners {
        unsigned int            sampling_rate;
@@ -94,11 +104,16 @@ static struct dbs_tuners dbs_tuners_ins = {
 
 static inline unsigned int get_cpu_idle_time(unsigned int cpu)
 {
-       return  kstat_cpu(cpu).cpustat.idle +
+       unsigned int add_nice = 0, ret;
+
+       if (dbs_tuners_ins.ignore_nice)
+               add_nice = kstat_cpu(cpu).cpustat.nice;
+
+       ret =   kstat_cpu(cpu).cpustat.idle +
                kstat_cpu(cpu).cpustat.iowait +
-               ( dbs_tuners_ins.ignore_nice ?
-                 kstat_cpu(cpu).cpustat.nice :
-                 0);
+               add_nice;
+
+       return ret;
 }
 
 /************************** sysfs interface ************************/
@@ -176,8 +191,7 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused,
        ret = sscanf (buf, "%u", &input);
 
        mutex_lock(&dbs_mutex);
-       if (ret != 1 || input > 100 || input < 0 ||
-                       input <= dbs_tuners_ins.down_threshold) {
+       if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) {
                mutex_unlock(&dbs_mutex);
                return -EINVAL;
        }
@@ -196,8 +210,7 @@ static ssize_t store_down_threshold(struct cpufreq_policy *unused,
        ret = sscanf (buf, "%u", &input);
 
        mutex_lock(&dbs_mutex);
-       if (ret != 1 || input > 100 || input < 0 ||
-                       input >= dbs_tuners_ins.up_threshold) {
+       if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) {
                mutex_unlock(&dbs_mutex);
                return -EINVAL;
        }
@@ -413,7 +426,7 @@ static void dbs_check_cpu(int cpu)
        }
 }
 
-static void do_dbs_timer(void *data)
+static void do_dbs_timer(struct work_struct *work)
 { 
        int i;
        mutex_lock(&dbs_mutex);
@@ -426,7 +439,6 @@ static void do_dbs_timer(void *data)
 
 static inline void dbs_timer_init(void)
 {
-       INIT_WORK(&dbs_work, do_dbs_timer, NULL);
        schedule_delayed_work(&dbs_work,
                        usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
        return;
@@ -444,6 +456,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
        unsigned int cpu = policy->cpu;
        struct cpu_dbs_info_s *this_dbs_info;
        unsigned int j;
+       int rc;
 
        this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
 
@@ -460,6 +473,13 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                        break;
                 
                mutex_lock(&dbs_mutex);
+
+               rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
+               if (rc) {
+                       mutex_unlock(&dbs_mutex);
+                       return rc;
+               }
+
                for_each_cpu_mask(j, policy->cpus) {
                        struct cpu_dbs_info_s *j_dbs_info;
                        j_dbs_info = &per_cpu(cpu_dbs_info, j);
@@ -472,7 +492,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
                this_dbs_info->enable = 1;
                this_dbs_info->down_skip = 0;
                this_dbs_info->requested_freq = policy->cur;
-               sysfs_create_group(&policy->kobj, &dbs_attr_group);
+
                dbs_enable++;
                /*
                 * Start the timerschedule work, when this governor