[PATCH] cpufreq: powerpc: replace CPUFREQ_ETERNAL with cpufreq transition latency for FSL e500mc Socs

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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.

---
 drivers/cpufreq/ppc-corenet-cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
index 051000f..ff7b625 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 +206,7 @@ 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;
-- 
1.8.4


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