From de4b10b242175fbeb89f80718ee4703fa11f2fc0 Mon Sep 17 00:00:00 2001
From: Steve Kondik <shade@chemlab.org>
Date: Fri, 8 Feb 2013 21:47:56 -0600
Subject: exynos3: power: Tuning and cleanups

* Tune the governor for better power usage and interactivity
* Reset tuning parameters if governor changes
* Cleanup

Change-Id: Ibe60ece836a0e56ba58e109bbea26cbd54d75421
---
 exynos3/s5pc110/power/power.c | 67 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 55 insertions(+), 12 deletions(-)

diff --git a/exynos3/s5pc110/power/power.c b/exynos3/s5pc110/power/power.c
index 552c098..ff42106 100644
--- a/exynos3/s5pc110/power/power.c
+++ b/exynos3/s5pc110/power/power.c
@@ -29,6 +29,8 @@
 #define SCALING_GOVERNOR_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor"
 #define BOOSTPULSE_ONDEMAND "/sys/devices/system/cpu/cpufreq/ondemand/boostpulse"
 #define BOOSTPULSE_INTERACTIVE "/sys/devices/system/cpu/cpufreq/interactive/boostpulse"
+#define TIMER_RATE_SCREEN_ON "30000"
+#define TIMER_RATE_SCREEN_OFF "150000"
 
 struct s5pc110_power_module {
     struct power_module base;
@@ -37,6 +39,8 @@ struct s5pc110_power_module {
     int boostpulse_warned;
 };
 
+static char governor[20];
+
 static int sysfs_read(char *path, char *s, int num_bytes)
 {
     char buf[80];
@@ -65,9 +69,30 @@ static int sysfs_read(char *path, char *s, int num_bytes)
     return ret;
 }
 
-static int get_scaling_governor(char governor[], int size) {
+static void sysfs_write(char *path, char *s)
+{
+    char buf[80];
+    int len;
+    int fd = open(path, O_WRONLY);
+
+    if (fd < 0) {
+        strerror_r(errno, buf, sizeof(buf));
+        ALOGE("Error opening %s: %s\n", path, buf);
+        return;
+    }
+
+    len = write(fd, s, strlen(s));
+    if (len < 0) {
+        strerror_r(errno, buf, sizeof(buf));
+        ALOGE("Error writing to %s: %s\n", path, buf);
+    }
+
+    close(fd);
+}
+
+static int get_scaling_governor() {
     if (sysfs_read(SCALING_GOVERNOR_PATH, governor,
-                size) == -1) {
+                sizeof(governor)) == -1) {
         // Can't obtain the scaling governor. Return.
         return -1;
     } else {
@@ -83,15 +108,35 @@ static int get_scaling_governor(char governor[], int size) {
     return 0;
 }
 
+static void s5pc110_power_set_interactive(struct power_module *module, int on)
+{
+    if (strncmp(governor, "interactive", 11) == 0)
+        sysfs_write("/sys/devices/system/cpu/cpufreq/interactive/timer_rate",
+                on ? TIMER_RATE_SCREEN_ON : TIMER_RATE_SCREEN_OFF);
+}
+
+static void configure_governor()
+{
+    s5pc110_power_set_interactive(NULL, 1);
+
+    if (strncmp(governor, "ondemand", 8) == 0) {
+        sysfs_write("/sys/devices/system/cpu/cpufreq/ondemand/up_threshold", "95");
+        sysfs_write("/sys/devices/system/cpu/cpufreq/ondemand/io_is_busy", "1");
+        sysfs_write("/sys/devices/system/cpu/cpufreq/ondemand/sampling_down_factor", "4");
+    } else if (strncmp(governor, "interactive", 11) == 0) {
+        sysfs_write("/sys/devices/system/cpu/cpufreq/interactive/min_sample_time", "90000");
+        sysfs_write("/sys/devices/system/cpu/cpufreq/interactive/above_hispeed_delay", "30000");
+    }
+}
+
 static int boostpulse_open(struct s5pc110_power_module *s5pc110)
 {
     char buf[80];
-    char governor[80];
 
     pthread_mutex_lock(&s5pc110->lock);
 
     if (s5pc110->boostpulse_fd < 0) {
-        if (get_scaling_governor(governor, sizeof(governor)) < 0) {
+        if (get_scaling_governor() < 0) {
             ALOGE("Can't read scaling governor.");
             s5pc110->boostpulse_warned = 1;
         } else {
@@ -104,8 +149,10 @@ static int boostpulse_open(struct s5pc110_power_module *s5pc110)
                 strerror_r(errno, buf, sizeof(buf));
                 ALOGE("Error opening %s boostpulse interface: %s\n", governor, buf);
                 s5pc110->boostpulse_warned = 1;
-            } else if (s5pc110->boostpulse_fd > 0)
+            } else if (s5pc110->boostpulse_fd > 0) {
+                configure_governor();
                 ALOGD("Opened %s boostpulse interface", governor);
+            }
         }
     }
 
@@ -152,14 +199,10 @@ static void s5pc110_power_hint(struct power_module *module, power_hint_t hint,
     }
 }
 
-static void s5pc110_power_set_interactive(struct power_module *module, int on)
-{
-    return;
-}
-
 static void s5pc110_power_init(struct power_module *module)
 {
-    return;
+    get_scaling_governor();
+    configure_governor();
 }
 
 static struct hw_module_methods_t power_module_methods = {
@@ -174,7 +217,7 @@ struct s5pc110_power_module HAL_MODULE_INFO_SYM = {
             hal_api_version: HARDWARE_HAL_API_VERSION,
             id: POWER_HARDWARE_MODULE_ID,
             name: "S5PC110 Power HAL",
-            author: "The Android Open Source Project",
+            author: "The CyanogenMod Project",
             methods: &power_module_methods,
         },
        init: s5pc110_power_init,
-- 
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