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authorZhuoyu Zhang <Zhuoyu.Zhang@freescale.com>2014-03-18 13:41:25 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-03-20 03:37:17 +0100
commitbfa709bc823fc32ee8dd5220d1711b46078235d8 (patch)
tree04ef279dd3a82117c9282d77101744dbe3cafbe6
parent0b443ead714f0cba797a7f2476dd756f22b5421e (diff)
cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs
According to the data provided by HW Team, at least 12 internal platform clock cycles are required to stabilize a DFS clock switch on FSL e500mc Socs. This patch replaces the CPUFREQ_ETERNAL with appropriate HW clock transition latency to make DFS governors work normally on Freescale e500mc boards. Signed-off-by: Zhuoyu Zhang <Zhuoyu.Zhang@freescale.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/cpufreq/ppc-corenet-cpufreq.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
index 037949d575b..3bd9123e702 100644
--- a/drivers/cpufreq/ppc-corenet-cpufreq.c
+++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
@@ -21,6 +21,7 @@
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/smp.h>
+#include <sysdev/fsl_soc.h>
/**
* struct cpu_data - per CPU data struct
@@ -205,7 +206,8 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
for_each_cpu(i, per_cpu(cpu_mask, cpu))
per_cpu(cpu_data, i) = data;
- policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+ policy->cpuinfo.transition_latency =
+ (12 * NSEC_PER_SEC) / fsl_get_sys_freq();
of_node_put(np);
return 0;