[PATCH 4/4] powernv:cpufreq: Implement the driver->get() method

[Gautham R. Shenoy]

From: "Gautham R. Shenoy" <ego at linux.vnet.ibm.com>

The current frequency of a cpu is reported through the sysfs file
cpuinfo_cur_freq. This requires the driver to implement a
"->get(unsigned int cpu)" method which will return the current
operating frequency.

Implement a function named powernv_cpufreq_get() which corresponds to
the required ->get() method.

Signed-off-by: Gautham R. Shenoy <ego at linux.vnet.ibm.com>
---
 drivers/cpufreq/powernv-cpufreq.c | 41 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index f0dae6f..5f43e4f 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -218,6 +218,46 @@ static inline void set_pmspr(unsigned long sprn, unsigned long val)
 	BUG();
 }
 
+/**
+ * Computes the current frequency on this cpu
+ * and stores the result in *ret_freq.
+ */
+static void powernv_get_cpu_freq(void *ret_freq)
+{
+	unsigned long pmspr_val;
+	long pstate_id;
+	int *cur_freq, freq;
+
+	cur_freq = (int *)ret_freq;
+	pmspr_val = get_pmspr(SPRN_PMSR);
+	pstate_id = pmspr_val;
+	pstate_id = pstate_id >> 56;
+	WARN_ON(pstate_id > 0);
+	freq = pstate_id_to_freq(pstate_id);
+	pr_debug("cpu %d pmsr %lx pstate_id %ld frequency %d \n",
+		smp_processor_id(), pmspr_val, pstate_id, freq);
+	*cur_freq = freq;
+}
+
+/**
+ * Returns the cpu frequency as reported by the firmware for 'cpu'.
+ * This value is reported through the sysfs file cpuinfo_cur_freq.
+ */
+unsigned int powernv_cpufreq_get(unsigned int cpu)
+{
+	int ret_freq;
+	cpumask_var_t sibling_mask;
+
+	if (!zalloc_cpumask_var(&sibling_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	powernv_cpu_to_core_mask(cpu, sibling_mask);
+	smp_call_function_any(sibling_mask, powernv_get_cpu_freq, &ret_freq, 1);
+
+	free_cpumask_var(sibling_mask);
+	return ret_freq;
+}
+
 static void set_pstate(void *pstate)
 {
 	unsigned long val;
@@ -310,6 +350,7 @@ static int powernv_cpufreq_target(struct cpufreq_policy *policy,
 static struct cpufreq_driver powernv_cpufreq_driver = {
 	.verify		= powernv_cpufreq_verify,
 	.target		= powernv_cpufreq_target,
+	.get		= powernv_cpufreq_get,
 	.init		= powernv_cpufreq_cpu_init,
 	.exit		= powernv_cpufreq_cpu_exit,
 	.name		= "powernv-cpufreq",
-- 
1.8.3.1