ARM: tegra: power Limit CPU complex speed through sysfs

Added sysfs node /sys/module/cpu_tegra/parameters/cpu_user_cap to set
maximum CPU rate from user space. Unlike per-cpu frequency governor
limit (scaling_max_freq), this cap is applied directly to common CPU
complex frequency underneath per-cpu governors.

(cherry picked from commit 5fbd5b19ddb43a03391957000f23b729f394b05b)
(cherry picked from commit bf81c8efc2c98e5008527ce019669dc57718f44b)

Change-Id: Ic2f152e1fd58f2f0062489309c0cffd32a2462ae
Reviewed-on: http://git-master/r/61711
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>

Rebase-Id: R800c2a4d5e097bdd29fa1b0b901264a2723abff0

1 files changed, 48 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c
index 90745de96c6b..d6793f87cc5f 100644
--- a/arch/arm/mach-tegra/cpu-tegra.c
+++ b/arch/arm/mach-tegra/cpu-tegra.c
@@ -84,6 +84,53 @@ static struct kernel_param_ops policy_ops = {
 module_param_cb(force_policy_max, &policy_ops, &force_policy_max, 0644);
 
 
+static unsigned int cpu_user_cap;
+
+static int cpu_user_cap_set(const char *arg, const struct kernel_param *kp)
+{
+	int ret;
+
+	mutex_lock(&tegra_cpu_lock);
+
+	ret = param_set_uint(arg, kp);
+	if (ret == 0) {
+#ifndef CONFIG_TEGRA_CPU_CAP_EXACT_FREQ
+		if (cpu_user_cap != 0) {
+			int i;
+			for (i = 0; freq_table[i].frequency !=
+				CPUFREQ_TABLE_END; i++) {
+				if (freq_table[i].frequency > cpu_user_cap)
+					break;
+			}
+			i = (i == 0) ? 0 : i - 1;
+			cpu_user_cap = freq_table[i].frequency;
+		}
+#endif
+		tegra_cpu_set_speed_cap(NULL);
+	}
+
+	mutex_unlock(&tegra_cpu_lock);
+	return ret;
+}
+
+static int cpu_user_cap_get(char *buffer, const struct kernel_param *kp)
+{
+	return param_get_uint(buffer, kp);
+}
+
+static struct kernel_param_ops cap_ops = {
+	.set = cpu_user_cap_set,
+	.get = cpu_user_cap_get,
+};
+module_param_cb(cpu_user_cap, &cap_ops, &cpu_user_cap, 0644);
+
+static unsigned int user_cap_speed(unsigned int requested_speed)
+{
+	if ((cpu_user_cap) && (requested_speed > cpu_user_cap))
+		return cpu_user_cap;
+	return requested_speed;
+}
+
 #ifdef CONFIG_TEGRA_THERMAL_THROTTLE
 
 static ssize_t show_throttle(struct cpufreq_policy *policy, char *buf)
@@ -444,6 +491,7 @@ int tegra_cpu_set_speed_cap(unsigned int *speed_cap)
 
 	new_speed = tegra_throttle_governor_speed(new_speed);
 	new_speed = edp_governor_speed(new_speed);
+	new_speed = user_cap_speed(new_speed);
 	if (speed_cap)
 		*speed_cap = new_speed;