From: Zucheng Zheng <zhengzucheng@xxxxxxxxxx>
On some specific platforms, the cpufreq driver does not define
cpufreq_driver.get() routine (eg:x86 intel_pstate driver), as a
result, the cpufreq_get() can't get the correct CPU frequency.
Modern x86 processors include the hardware needed to accurately
calculate frequency over an interval -- APERF, MPERF and the TSC.
Here we use arch_freq_get_on_cpu() in preference to any driver
driver-specific cpufreq_driver.get() routine to get CPU frequency.
Fixes: f8475cef9008 ("x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF")
Signed-off-by: Zucheng Zheng <zhengzucheng@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 80f535cc8a75..d777257b4454 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1806,10 +1806,14 @@ unsigned int cpufreq_get(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
unsigned int ret_freq = 0;
+ unsigned int freq;
if (policy) {
down_read(&policy->rwsem);
- if (cpufreq_driver->get)
+ freq = arch_freq_get_on_cpu(policy->cpu);
+ if (freq)
+ ret_freq = freq;
+ else if (cpufreq_driver->get)
ret_freq = __cpufreq_get(policy);
up_read(&policy->rwsem);
--
2.18.0.huawei.25
