[CPUFREQ] add cpufreq_update_policy()

Add a new cpufreq_update_policy call:

Certain cpufreq policy notifers have different needs at different times.
Thus it needs to be possible to re-evaluate an already set cpufreq policy.
Note that the cpufreq policy should only be set by one person: the user.
Not any other in-kernel code [with one exception, of course: during
booting].

drivers/cpufreq/cpufreq.c

@@ -741,26 +741,9 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
 EXPORT_SYMBOL(cpufreq_get_policy);
 
 
-/**
- *	cpufreq_set_policy - set a new CPUFreq policy
- *	@policy: policy to be set.
- *
- *	Sets a new CPU frequency and voltage scaling policy.
- */
-int cpufreq_set_policy(struct cpufreq_policy *policy)
+static int __cpufreq_set_policy(struct cpufreq_policy *data, struct cpufreq_policy *policy)
 {
 	int ret = 0;
-	struct cpufreq_policy *data;
-
-	if (!policy)
-		return -EINVAL;
-
-	data = cpufreq_cpu_get(policy->cpu);
-	if (!data)
-		return -EINVAL;
-
-	/* lock this CPU */
-	down(&data->lock);
 
 	memcpy(&policy->cpuinfo, 
 	       &data->cpuinfo, 
@@ -827,6 +810,36 @@ int cpufreq_set_policy(struct cpufreq_policy *policy)
 	}
 
  error_out:
+	return ret;
+}
+
+/**
+ *	cpufreq_set_policy - set a new CPUFreq policy
+ *	@policy: policy to be set.
+ *
+ *	Sets a new CPU frequency and voltage scaling policy.
+ */
+int cpufreq_set_policy(struct cpufreq_policy *policy)
+{
+	int ret = 0;
+	struct cpufreq_policy *data;
+
+	if (!policy)
+		return -EINVAL;
+
+	data = cpufreq_cpu_get(policy->cpu);
+	if (!data)
+		return -EINVAL;
+
+	/* lock this CPU */
+	down(&data->lock);
+
+	ret = __cpufreq_set_policy(data, policy);
+	data->user_policy.min = data->min;
+	data->user_policy.max = data->max;
+	data->user_policy.policy = data->policy;
+	data->user_policy.governor = data->governor;
+
 	up(&data->lock);
 	cpufreq_cpu_put(data);
 
@@ -835,6 +848,41 @@ int cpufreq_set_policy(struct cpufreq_policy *policy)
 EXPORT_SYMBOL(cpufreq_set_policy);
 
 
+/**
+ *	cpufreq_update_policy - re-evaluate an existing cpufreq policy
+ *	@cpu: CPU which shall be re-evaluated
+ *
+ *	Usefull for policy notifiers which have different necessities
+ *	at different times.
+ */
+int cpufreq_update_policy(unsigned int cpu)
+{
+	struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
+	struct cpufreq_policy policy;
+	int ret = 0;
+
+	if (!data)
+		return -ENODEV;
+
+	down(&data->lock);
+
+	memcpy(&policy, 
+	       &data, 
+	       sizeof(struct cpufreq_policy));
+	policy.min = data->user_policy.min;
+	policy.max = data->user_policy.max;
+	policy.policy = data->user_policy.policy;
+	policy.governor = data->user_policy.governor;
+
+	ret = __cpufreq_set_policy(data, &policy);
+
+	up(&data->lock);
+
+	cpufreq_cpu_put(data);
+	return ret;
+}
+EXPORT_SYMBOL(cpufreq_update_policy);
+
 
 /*********************************************************************
  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *

include/linux/cpufreq.h

@@ -60,6 +60,13 @@ struct cpufreq_cpuinfo {
 	unsigned int		transition_latency; /* in 10^(-9) s */
 };
 
+struct cpufreq_real_policy {
+	unsigned int		min;    /* in kHz */
+	unsigned int		max;    /* in kHz */
+        unsigned int		policy; /* see above */
+	struct cpufreq_governor	*governor; /* see below */
+};
+
 struct cpufreq_policy {
 	unsigned int		cpu;    /* cpu nr */
 	struct cpufreq_cpuinfo	cpuinfo;/* see above */
@@ -74,6 +81,8 @@ struct cpufreq_policy {
  	struct semaphore	lock;   /* CPU ->setpolicy or ->target may
 					   only be called once a time */
 
+	struct cpufreq_real_policy	user_policy;
+
 	struct kobject		kobj;
 	struct completion	kobj_unregister;
 };
@@ -217,6 +226,7 @@ struct freq_attr {
  *********************************************************************/
 int cpufreq_set_policy(struct cpufreq_policy *policy);
 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
+int cpufreq_update_policy(unsigned int cpu);
 
 /* the proc_intf.c needs this */
 int cpufreq_parse_governor (char *str_governor, unsigned int *policy, struct cpufreq_governor **governor);