sdm660-common: Introduce kernelspace battery saver

* Needs Kernel side support
 * This activates kernelspace battery saver via powerhal whenever
   battery saver is enabled in userspace, thereby lowering power
   consumption at kernel-level by disabling boosts and such

Signed-off-by: clarencelol <clarencekuiek@icloud.com>
Change-Id: I2623503db27d7518de519bcaa3f5af6ab83879d0

BoardConfigCommon.mk

@@ -79,6 +79,9 @@ BOARD_SUPPORTS_SOUND_TRIGGER := true
 USE_CUSTOM_AUDIO_POLICY := 1
 USE_XML_AUDIO_POLICY_CONF := 1
 
+# Battery Saver
+TARGET_POWERHAL_MODE_EXT := $(COMMON_PATH)/power-libperfmgr/power/power-mode.cpp
+
 # Bluetooth
 BOARD_HAVE_BLUETOOTH := true
 BOARD_HAVE_BLUETOOTH_QCOM := true

power-libperfmgr/power/power-mode.cpp

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2020 The LineageOS Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <aidl/android/hardware/power/BnPower.h>
+#include <android-base/file.h>
+#include "power-common.h"
+
+#define BATTERY_SAVER_NODE "/sys/module/battery_saver/parameters/enabled"
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace power {
+namespace impl {
+
+using ::aidl::android::hardware::power::Mode;
+
+bool isDeviceSpecificModeSupported(Mode type, bool* _aidl_return) {
+    switch (type) {
+        case Mode::LOW_POWER:
+            *_aidl_return = true;
+            return true;
+        default:
+            return false;
+    }
+}
+
+bool setDeviceSpecificMode(Mode type, bool enabled) {
+    switch (type) {
+        case Mode::LOW_POWER:
+            ::android::base::WriteStringToFile(enabled ? "Y" : "N", BATTERY_SAVER_NODE, true);
+            return true;
+        default:
+            return false;
+    }
+}
+
+}  // namespace impl
+}  // namespace power
+}  // namespace hardware
+}  // namespace android
+}  // namespace aidl

rootdir/etc/init.target.rc

@@ -75,6 +75,9 @@ on init
     chmod 0664 /sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq
     chmod 0664 /sys/devices/system/cpu/cpu4/cpufreq/scaling_min_freq
 
+    chown system system /sys/module/battery_saver/parameters/enabled
+    chmod 0664 /sys/module/battery_saver/parameters/enabled
+
 on fs
     wait /dev/block/platform/soc/${ro.boot.bootdevice}
     symlink /dev/block/platform/soc/${ro.boot.bootdevice} /dev/block/bootdevice

sepolicy/vendor/file.te

@@ -18,3 +18,6 @@ type kcal_dev, sysfs_type, fs_type;
 
 # Sockets
 type audio_socket, file_type;
+
+# Battery Saver
+type sysfs_battery_saver, fs_type, sysfs_type;

sepolicy/vendor/genfs_contexts

@@ -2,6 +2,9 @@
 genfscon sysfs /devices/platform/soc/c175000.i2c/i2c-1/1-0062                                                                                        u:object_r:sysfs_battery_supply:s0
 genfscon sysfs /devices/platform/soc/c176000.i2c/i2c-2/2-001d                                                                                        u:object_r:sysfs_battery_supply:s0
 
+# Battery Saver
+genfscon sysfs /module/battery_saver/parameters/enabled                                                                                              u:object_r:sysfs_battery_saver:s0
+
 # Camera
 genfscon sysfs /devices/platform/soc/ca0c000.qcom,cci/ca0c000.qcom,cci:qcom,camera@0/video4linux/video2/name                                         u:object_r:sysfs_graphics:s0
 genfscon sysfs /devices/platform/soc/ca0c000.qcom,cci/ca0c000.qcom,cci:qcom,camera@1/video4linux/video3/name                                         u:object_r:sysfs_graphics:s0

sepolicy/vendor/hal_power_default.te

@@ -1,5 +1,7 @@
 allow hal_power_default cgroup:file read;
 allow hal_power_default device_latency:chr_file rw_file_perms;
+allow hal_power_default sysfs_battery_saver:dir r_dir_perms;
+allow hal_power_default sysfs_battery_saver:file rw_file_perms;
 allow hal_power_default { sysfs_devfreq sysfs_kgsl }:dir search;
 allow hal_power_default { sysfs_devfreq sysfs_kgsl }:{ file lnk_file } rw_file_perms;
 allow hal_power_default sysfs_devices_system_cpu:file rw_file_perms;