ARM: tegra: power: Check Tegra3 auto-hotplug speed balance

When current CPU complex frequency is above target range:
- bring new core on-line only if cpufreq governor requests for
all already on-lined CPUs are above 50% of current CPU frequency
- off-line one core (despite high pick request) if cpufreq
governor requests for at least 2 on-lined CPUs are below 25% of
current CPU frequency
- do nothing if neither of the above conditions is true

Original-Change-Id: I77e1bd543a8fadd51974f7d574f256a6e7e2979a
Reviewed-on: http://git-master/r/29702
Reviewed-by: Aleksandr Frid <afrid@nvidia.com>
Tested-by: Aleksandr Frid <afrid@nvidia.com>
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
Tested-by: Diwakar Tundlam <dtundlam@nvidia.com>
Reviewed-by: Scott Williams <scwilliams@nvidia.com>

Rebase-Id: Rc5c717454d1e09ca97ccc79fff60cb33fcf854e9

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c
index baf543674c3d..1d61146b50cc 100644
--- a/arch/arm/mach-tegra/cpu-tegra.c
+++ b/arch/arm/mach-tegra/cpu-tegra.c
@@ -362,6 +362,17 @@ static int tegra_update_cpu_speed(unsigned long rate)
 	return 0;
 }
 
+unsigned int tegra_count_slow_cpus(unsigned long speed_limit)
+{
+	unsigned int cnt = 0;
+	int i;
+
+	for_each_online_cpu(i)
+		if (target_cpu_speed[i] <= speed_limit)
+			cnt++;
+	return cnt;
+}
+
 unsigned int tegra_get_slowest_cpu_n(void) {
 	unsigned int cpu = nr_cpu_ids;
 	unsigned long rate = ULONG_MAX;