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cpufreq: Add a notifer chain that governors can use to report information

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Some modules can benefit from getting additional information cpufreq
governors use to make frequency switch decisions.
This change lays down a basic framework that the governors can use
to report additional information (Eg: CPU's load) information to
the clients that subscribe to cpufreq govinfo notifier chain.

Change-Id: I511b4bdb7d12394a31ce5352ae47553861e49303
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
[imaund@codeaurora.org: resolved context conflicts]
Signed-off-by: Ian Maund <imaund@codeaurora.org>
This commit is contained in:
Rohit Gupta 2014-11-14 17:53:15 -08:00 • committed by David Keitel
parent db35fc6d65
commit db44d1e057
2 changed files with 34 additions and 1 deletions
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21
drivers/cpufreq/cpufreq.c
View file

@ -127,6 +127,7 @@ static void handle_update(struct work_struct *work);
*/
static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
static struct srcu_notifier_head cpufreq_transition_notifier_list;
struct atomic_notifier_head cpufreq_govinfo_notifier_list;
static bool init_cpufreq_transition_notifier_list_called;
static int __init init_cpufreq_transition_notifier_list(void)
@ -137,6 +138,15 @@ static int __init init_cpufreq_transition_notifier_list(void)
}
pure_initcall(init_cpufreq_transition_notifier_list);
static bool init_cpufreq_govinfo_notifier_list_called;
static int __init init_cpufreq_govinfo_notifier_list(void)
{
ATOMIC_INIT_NOTIFIER_HEAD(&cpufreq_govinfo_notifier_list);
init_cpufreq_govinfo_notifier_list_called = true;
return 0;
}
pure_initcall(init_cpufreq_govinfo_notifier_list);
static int off __read_mostly;
static int cpufreq_disabled(void)
{
@ -1703,7 +1713,8 @@ int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
if (cpufreq_disabled())
return -EINVAL;
WARN_ON(!init_cpufreq_transition_notifier_list_called);
WARN_ON(!init_cpufreq_transition_notifier_list_called ||
!init_cpufreq_govinfo_notifier_list_called);
switch (list) {
case CPUFREQ_TRANSITION_NOTIFIER:
@ -1714,6 +1725,10 @@ int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
ret = blocking_notifier_chain_register(
&cpufreq_policy_notifier_list, nb);
break;
case CPUFREQ_GOVINFO_NOTIFIER:
ret = atomic_notifier_chain_register(
&cpufreq_govinfo_notifier_list, nb);
break;
default:
ret = -EINVAL;
}
@ -1748,6 +1763,10 @@ int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
ret = blocking_notifier_chain_unregister(
&cpufreq_policy_notifier_list, nb);
break;
case CPUFREQ_GOVINFO_NOTIFIER:
ret = atomic_notifier_chain_unregister(
&cpufreq_govinfo_notifier_list, nb);
break;
default:
ret = -EINVAL;
}

14
include/linux/cpufreq.h
View file

@ -361,6 +361,7 @@ static inline void cpufreq_resume(void) {}
#define CPUFREQ_TRANSITION_NOTIFIER (0)
#define CPUFREQ_POLICY_NOTIFIER (1)
#define CPUFREQ_GOVINFO_NOTIFIER (2)
/* Transition notifiers */
#define CPUFREQ_PRECHANGE (0)
@ -373,6 +374,9 @@ static inline void cpufreq_resume(void) {}
#define CPUFREQ_CREATE_POLICY (3)
#define CPUFREQ_REMOVE_POLICY (4)
/* Govinfo Notifiers */
#define CPUFREQ_LOAD_CHANGE (0)
#ifdef CONFIG_CPU_FREQ
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
@ -381,6 +385,16 @@ void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs);
void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, int transition_failed);
/*
* Governor specific info that can be passed to modules that subscribe
* to CPUFREQ_GOVINFO_NOTIFIER
*/
struct cpufreq_govinfo {
unsigned int cpu;
unsigned int load;
unsigned int sampling_rate_us;
};
extern struct atomic_notifier_head cpufreq_govinfo_notifier_list;
#else /* CONFIG_CPU_FREQ */
static inline int cpufreq_register_notifier(struct notifier_block *nb,