On Thu, Mar 20, 2014 at 05:41:00PM +0530, Gautham R. Shenoy wrote:
From: "Gautham R. Shenoy" <redacted>
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 reads the local
pstate from the PMSR and returns the corresponding frequency.
Set the powernv_cpufreq_driver.get hook to powernv_cpufreq_get().
Forgot to add
Reviewed-by: Preeti U Murthy [off-list ref]
quoted hunk ↗ jump to hunk
Signed-off-by: Gautham R. Shenoy <redacted>
---
drivers/cpufreq/powernv-cpufreq.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 46bee8a..ef6ed8c 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -206,6 +206,43 @@ 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_read_cpu_freq(void *ret_freq)
+{
+ unsigned long pmspr_val;
+ s8 local_pstate_id;
+ int *cur_freq, freq, pstate_id;
+
+ cur_freq = (int *)ret_freq;
+ pmspr_val = get_pmspr(SPRN_PMSR);
+
+ /* The local pstate id corresponds bits 48..55 in the PMSR.
+ * Note: Watch out for the sign! */
+ local_pstate_id = (pmspr_val >> 48) & 0xFF;
+ pstate_id = local_pstate_id;
+
+ freq = pstate_id_to_freq(pstate_id);
+ pr_debug("cpu %d pmsr %lx pstate_id %d 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;
+
+ smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
+ &ret_freq, 1);
+ return ret_freq;
+}
+
static void set_pstate(void *pstate)
{
unsigned long val;@@ -297,6 +334,7 @@ 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