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cpufreq: Split cpufreq_governor() into simpler functions
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The cpufreq_governor() routine is used by the cpufreq core to invoke
the current governor's ->governor() callback with appropriate arguments
and do some housekeeping related to that.  Unfortunately, the way it
mixes different governor events in one code path makes it rather hard
to follow the code.

For this reason, split cpufreq_governor() into five simpler functions
that each will handle just one specific governor event and put all of
the code related to the given event into its own function.

This change is a prerequisite for a redesign of the cpufreq governor
API that will be done subsequently.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Rafael J. Wysocki committed May 30, 2016
1 parent 16de72b commit a92604b
Showing 1 changed file with 70 additions and 43 deletions.
113 changes: 70 additions & 43 deletions drivers/cpufreq/cpufreq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,19 +74,12 @@ static inline bool has_target(void)
}

/* internal prototypes */
static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
static int cpufreq_init_governor(struct cpufreq_policy *policy);
static void cpufreq_exit_governor(struct cpufreq_policy *policy);
static int cpufreq_start_governor(struct cpufreq_policy *policy);

static inline void cpufreq_exit_governor(struct cpufreq_policy *policy)
{
(void)cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
}

static inline void cpufreq_stop_governor(struct cpufreq_policy *policy)
{
(void)cpufreq_governor(policy, CPUFREQ_GOV_STOP);
}
static void cpufreq_stop_governor(struct cpufreq_policy *policy);
static void cpufreq_governor_limits(struct cpufreq_policy *policy);

/**
* Two notifier lists: the "policy" list is involved in the
Expand Down Expand Up @@ -1997,7 +1990,7 @@ __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
return NULL;
}

static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
static int cpufreq_init_governor(struct cpufreq_policy *policy)
{
int ret;

Expand All @@ -2011,57 +2004,91 @@ static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
if (!policy->governor)
return -EINVAL;

if (event == CPUFREQ_GOV_POLICY_INIT) {
if (policy->governor->max_transition_latency &&
policy->cpuinfo.transition_latency >
policy->governor->max_transition_latency) {
struct cpufreq_governor *gov = cpufreq_fallback_governor();

if (gov) {
pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
policy->governor->name, gov->name);
policy->governor = gov;
} else {
return -EINVAL;
}
}
if (policy->governor->max_transition_latency &&
policy->cpuinfo.transition_latency >
policy->governor->max_transition_latency) {
struct cpufreq_governor *gov = cpufreq_fallback_governor();

if (!try_module_get(policy->governor->owner))
if (gov) {
pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
policy->governor->name, gov->name);
policy->governor = gov;
} else {
return -EINVAL;
}
}

pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
if (!try_module_get(policy->governor->owner))
return -EINVAL;

ret = policy->governor->governor(policy, event);
pr_debug("%s: for CPU %u\n", __func__, policy->cpu);

if (event == CPUFREQ_GOV_POLICY_INIT) {
if (ret)
module_put(policy->governor->owner);
else
policy->governor->initialized++;
} else if (event == CPUFREQ_GOV_POLICY_EXIT) {
policy->governor->initialized--;
ret = policy->governor->governor(policy, CPUFREQ_GOV_POLICY_INIT);
if (ret) {
module_put(policy->governor->owner);
return ret;
}

return ret;
policy->governor->initialized++;
return 0;
}

static void cpufreq_exit_governor(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;

pr_debug("%s: for CPU %u\n", __func__, policy->cpu);

policy->governor->governor(policy, CPUFREQ_GOV_POLICY_EXIT);

policy->governor->initialized--;
module_put(policy->governor->owner);
}

static int cpufreq_start_governor(struct cpufreq_policy *policy)
{
int ret;

if (cpufreq_suspended)
return 0;

if (!policy->governor)
return -EINVAL;

pr_debug("%s: for CPU %u\n", __func__, policy->cpu);

if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
cpufreq_update_current_freq(policy);

ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
ret = policy->governor->governor(policy, CPUFREQ_GOV_START);
if (ret)
return ret;

cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
return 0;
}

static void cpufreq_stop_governor(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;

pr_debug("%s: for CPU %u\n", __func__, policy->cpu);

policy->governor->governor(policy, CPUFREQ_GOV_STOP);
}

static void cpufreq_governor_limits(struct cpufreq_policy *policy)
{
if (cpufreq_suspended || !policy->governor)
return;

pr_debug("%s: for CPU %u\n", __func__, policy->cpu);

policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
}

int cpufreq_register_governor(struct cpufreq_governor *governor)
{
int err;
Expand Down Expand Up @@ -2200,7 +2227,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,

if (new_policy->governor == policy->governor) {
pr_debug("cpufreq: governor limits update\n");
cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
cpufreq_governor_limits(policy);
return 0;
}

Expand All @@ -2216,7 +2243,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,

/* start new governor */
policy->governor = new_policy->governor;
ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
ret = cpufreq_init_governor(policy);
if (!ret) {
ret = cpufreq_start_governor(policy);
if (!ret) {
Expand All @@ -2230,7 +2257,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
pr_debug("starting governor %s failed\n", policy->governor->name);
if (old_gov) {
policy->governor = old_gov;
if (cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
if (cpufreq_init_governor(policy))
policy->governor = NULL;
else
cpufreq_start_governor(policy);
Expand Down Expand Up @@ -2328,7 +2355,7 @@ static int cpufreq_boost_set_sw(int state)

down_write(&policy->rwsem);
policy->user_policy.max = policy->max;
cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
cpufreq_governor_limits(policy);
up_write(&policy->rwsem);
}
}
Expand Down

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