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path: root/drivers/cpufreq/cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c112
1 files changed, 69 insertions, 43 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 80f535cc8a75..2cad42774164 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -28,6 +28,7 @@
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/tick.h>
+#include <linux/units.h>
#include <trace/events/power.h>
static LIST_HEAD(cpufreq_policy_list);
@@ -947,13 +948,14 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
{
struct cpufreq_policy *policy = to_policy(kobj);
struct freq_attr *fattr = to_attr(attr);
- ssize_t ret;
+ ssize_t ret = -EBUSY;
if (!fattr->show)
return -EIO;
down_read(&policy->rwsem);
- ret = fattr->show(policy, buf);
+ if (likely(!policy_is_inactive(policy)))
+ ret = fattr->show(policy, buf);
up_read(&policy->rwsem);
return ret;
@@ -964,7 +966,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
{
struct cpufreq_policy *policy = to_policy(kobj);
struct freq_attr *fattr = to_attr(attr);
- ssize_t ret = -EINVAL;
+ ssize_t ret = -EBUSY;
if (!fattr->store)
return -EIO;
@@ -978,7 +980,8 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
if (cpu_online(policy->cpu)) {
down_write(&policy->rwsem);
- ret = fattr->store(policy, buf, count);
+ if (likely(!policy_is_inactive(policy)))
+ ret = fattr->store(policy, buf, count);
up_write(&policy->rwsem);
}
@@ -1019,11 +1022,12 @@ static void add_cpu_dev_symlink(struct cpufreq_policy *policy, unsigned int cpu,
dev_err(dev, "cpufreq symlink creation failed\n");
}
-static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
+static void remove_cpu_dev_symlink(struct cpufreq_policy *policy, int cpu,
struct device *dev)
{
dev_dbg(dev, "%s: Removing symlink\n", __func__);
sysfs_remove_link(&dev->kobj, "cpufreq");
+ cpumask_clear_cpu(cpu, policy->real_cpus);
}
static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
@@ -1337,12 +1341,12 @@ static int cpufreq_online(unsigned int cpu)
down_write(&policy->rwsem);
policy->cpu = cpu;
policy->governor = NULL;
- up_write(&policy->rwsem);
} else {
new_policy = true;
policy = cpufreq_policy_alloc(cpu);
if (!policy)
return -ENOMEM;
+ down_write(&policy->rwsem);
}
if (!new_policy && cpufreq_driver->online) {
@@ -1382,7 +1386,6 @@ static int cpufreq_online(unsigned int cpu)
cpumask_copy(policy->related_cpus, policy->cpus);
}
- down_write(&policy->rwsem);
/*
* affected cpus must always be the one, which are online. We aren't
* managing offline cpus here.
@@ -1531,9 +1534,9 @@ static int cpufreq_online(unsigned int cpu)
out_destroy_policy:
for_each_cpu(j, policy->real_cpus)
- remove_cpu_dev_symlink(policy, get_cpu_device(j));
+ remove_cpu_dev_symlink(policy, j, get_cpu_device(j));
- up_write(&policy->rwsem);
+ cpumask_clear(policy->cpus);
out_offline_policy:
if (cpufreq_driver->offline)
@@ -1544,6 +1547,8 @@ out_exit_policy:
cpufreq_driver->exit(policy);
out_free_policy:
+ up_write(&policy->rwsem);
+
cpufreq_policy_free(policy);
return ret;
}
@@ -1575,47 +1580,36 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
return 0;
}
-static int cpufreq_offline(unsigned int cpu)
+static void __cpufreq_offline(unsigned int cpu, struct cpufreq_policy *policy)
{
- struct cpufreq_policy *policy;
int ret;
- pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
-
- policy = cpufreq_cpu_get_raw(cpu);
- if (!policy) {
- pr_debug("%s: No cpu_data found\n", __func__);
- return 0;
- }
-
- down_write(&policy->rwsem);
if (has_target())
cpufreq_stop_governor(policy);
cpumask_clear_cpu(cpu, policy->cpus);
- if (policy_is_inactive(policy)) {
- if (has_target())
- strncpy(policy->last_governor, policy->governor->name,
- CPUFREQ_NAME_LEN);
- else
- policy->last_policy = policy->policy;
- } else if (cpu == policy->cpu) {
- /* Nominate new CPU */
- policy->cpu = cpumask_any(policy->cpus);
- }
-
- /* Start governor again for active policy */
if (!policy_is_inactive(policy)) {
+ /* Nominate a new CPU if necessary. */
+ if (cpu == policy->cpu)
+ policy->cpu = cpumask_any(policy->cpus);
+
+ /* Start the governor again for the active policy. */
if (has_target()) {
ret = cpufreq_start_governor(policy);
if (ret)
pr_err("%s: Failed to start governor\n", __func__);
}
- goto unlock;
+ return;
}
+ if (has_target())
+ strncpy(policy->last_governor, policy->governor->name,
+ CPUFREQ_NAME_LEN);
+ else
+ policy->last_policy = policy->policy;
+
if (cpufreq_thermal_control_enabled(cpufreq_driver)) {
cpufreq_cooling_unregister(policy->cdev);
policy->cdev = NULL;
@@ -1634,8 +1628,24 @@ static int cpufreq_offline(unsigned int cpu)
cpufreq_driver->exit(policy);
policy->freq_table = NULL;
}
+}
+
+static int cpufreq_offline(unsigned int cpu)
+{
+ struct cpufreq_policy *policy;
+
+ pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
+
+ policy = cpufreq_cpu_get_raw(cpu);
+ if (!policy) {
+ pr_debug("%s: No cpu_data found\n", __func__);
+ return 0;
+ }
+
+ down_write(&policy->rwsem);
+
+ __cpufreq_offline(cpu, policy);
-unlock:
up_write(&policy->rwsem);
return 0;
}
@@ -1653,19 +1663,25 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
if (!policy)
return;
- if (cpu_online(cpu))
- cpufreq_offline(cpu);
+ down_write(&policy->rwsem);
- cpumask_clear_cpu(cpu, policy->real_cpus);
- remove_cpu_dev_symlink(policy, dev);
+ if (cpu_online(cpu))
+ __cpufreq_offline(cpu, policy);
- if (cpumask_empty(policy->real_cpus)) {
- /* We did light-weight exit earlier, do full tear down now */
- if (cpufreq_driver->offline)
- cpufreq_driver->exit(policy);
+ remove_cpu_dev_symlink(policy, cpu, dev);
- cpufreq_policy_free(policy);
+ if (!cpumask_empty(policy->real_cpus)) {
+ up_write(&policy->rwsem);
+ return;
}
+
+ /* We did light-weight exit earlier, do full tear down now */
+ if (cpufreq_driver->offline)
+ cpufreq_driver->exit(policy);
+
+ up_write(&policy->rwsem);
+
+ cpufreq_policy_free(policy);
}
/**
@@ -1707,6 +1723,16 @@ static unsigned int cpufreq_verify_current_freq(struct cpufreq_policy *policy, b
return new_freq;
if (policy->cur != new_freq) {
+ /*
+ * For some platforms, the frequency returned by hardware may be
+ * slightly different from what is provided in the frequency
+ * table, for example hardware may return 499 MHz instead of 500
+ * MHz. In such cases it is better to avoid getting into
+ * unnecessary frequency updates.
+ */
+ if (abs(policy->cur - new_freq) < HZ_PER_MHZ)
+ return policy->cur;
+
cpufreq_out_of_sync(policy, new_freq);
if (update)
schedule_work(&policy->update);
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-05 13:35:27 +0000