health/2.0/README.md

   1 # Upgrading from Health 1.0 HAL
   2
   3 1. Remove `android.hardware.health@1.0*` from `PRODUCT_PACKAGES`
   4    in `device/<manufacturer>/<device>/device.mk`
   5
   6 1. If the device does not have a vendor-specific `libhealthd` AND does not
   7    implement storage-related APIs, just do the following:
   8
   9    ```mk
  10    PRODUCT_PACKAGES += android.hardware.health@2.0-service
  11    ```
  12
  13    Otherwise, continue to the next step.
  14
  15 1. Create directory
  16    `device/<manufacturer>/<device>/health`
  17
  18 1. Create `device/<manufacturer>/<device>/health/Android.bp`
  19    (or equivalent `device/<manufacturer>/<device>/health/Android.mk`)
  20
  21     ```bp
  22     cc_binary {
  23         name: "android.hardware.health@2.0-service.<device>",
  24         init_rc: ["android.hardware.health@2.0-service.<device>.rc"],
  25         proprietary: true,
  26         relative_install_path: "hw",
  27         srcs: [
  28             "HealthService.cpp",
  29         ],
  30
  31         cflags: [
  32             "-Wall",
  33             "-Werror",
  34         ],
  35
  36         static_libs: [
  37             "android.hardware.health@2.0-impl",
  38             "android.hardware.health@1.0-convert",
  39             "libhealthservice",
  40             "libbatterymonitor",
  41         ],
  42
  43         shared_libs: [
  44             "libbase",
  45             "libcutils",
  46             "libhidlbase",
  47             "libhidltransport",
  48             "libutils",
  49             "android.hardware.health@2.0",
  50         ],
  51
  52         header_libs: ["libhealthd_headers"],
  53
  54         overrides: [
  55             "healthd",
  56         ],
  57     }
  58     ```
  59
  60     1. (recommended) To remove `healthd` from the build, keep "overrides" section.
  61     1. To keep `healthd` in the build, remove "overrides" section.
  62
  63 1. Create `device/<manufacturer>/<device>/health/android.hardware.health@2.0-service.<device>.rc`
  64
  65     ```rc
  66     service vendor.health-hal-2-0 /vendor/bin/hw/android.hardware.health@2.0-service.<device>
  67         class hal
  68         user system
  69         group system
  70         file /dev/kmsg w
  71     ```
  72
  73 1. Create `device/<manufacturer>/<device>/health/HealthService.cpp`:
  74
  75     ```c++
  76     #include <health2/service.h>
  77     int main() { return health_service_main(); }
  78     ```
  79
  80 1. `libhealthd` dependency:
  81
  82     1. If the device has a vendor-specific `libhealthd.<soc>`, add it to static_libs.
  83
  84     1. If the device does not have a vendor-specific `libhealthd`, add the following
  85         lines to `HealthService.cpp`:
  86
  87         ```c++
  88         #include <healthd/healthd.h>
  89         void healthd_board_init(struct healthd_config*) {}
  90
  91         int healthd_board_battery_update(struct android::BatteryProperties*) {
  92             // return 0 to log periodic polled battery status to kernel log
  93             return 0;
  94         }
  95         ```
  96
  97 1. Storage related APIs:
  98
  99     1. If the device does not implement `IHealth.getDiskStats` and
 100         `IHealth.getStorageInfo`, add `libstoragehealthdefault` to `static_libs`.
 101
 102     1. If the device implements one of these two APIs, add and implement the
 103         following functions in `HealthService.cpp`:
 104
 105         ```c++
 106         void get_storage_info(std::vector<struct StorageInfo>& info) {
 107             // ...
 108         }
 109         void get_disk_stats(std::vector<struct DiskStats>& stats) {
 110             // ...
 111         }
 112         ```
 113
 114 1. Update necessary SELinux permissions. For example,
 115
 116     ```
 117     # device/<manufacturer>/<device>/sepolicy/vendor/file_contexts
 118     /vendor/bin/hw/android\.hardware\.health@2\.0-service.<device> u:object_r:hal_health_default_exec:s0
 119
 120     # device/<manufacturer>/<device>/sepolicy/vendor/hal_health_default.te
 121     # Add device specific permissions to hal_health_default domain, especially
 122     # if a device-specific libhealthd is used and/or device-specific storage related
 123     # APIs are implemented.
 124     ```
 125
 126 1. Implementing health HAL in recovery. The health HAL is used for battery
 127 status checks during OTA for non-A/B devices. If the health HAL is not
 128 implemented in recovery, `is_battery_ok()` will always return `true`.
 129
 130     1. If the device does not have a vendor-specific `libhealthd`, nothing needs to
 131     be done. A "backup" implementation is provided in
 132     `android.hardware.health@2.0-impl-default`, which is always installed to recovery
 133     image by default.
 134
 135     1. If the device does have a vendor-specific `libhealthd`, implement the following
 136     module and include it in `PRODUCT_PACKAGES` (replace `<device>` with appropriate
 137     strings):
 138
 139     ```bp
 140     // Android.bp
 141     cc_library_shared {
 142         name: "android.hardware.health@2.0-impl-<device>",
 143         recovery_available: true,
 144         relative_install_path: "hw",
 145         static_libs: [
 146             "android.hardware.health@2.0-impl",
 147             "libhealthd.<device>"
 148             // Include the following or implement device-specific storage APIs
 149             "libhealthstoragedefault",
 150         ],
 151         srcs: [
 152             "HealthImpl.cpp",
 153         ],
 154         overrides: [
 155             "android.hardware.health@2.0-impl-default",
 156         ],
 157     }
 158     ```
 159
 160     ```c++
 161     // HealthImpl.cpp
 162     #include <health2/Health.h>
 163     #include <healthd/healthd.h>
 164     using android::hardware::health::V2_0::IHealth;
 165     using android::hardware::health::V2_0::implementation::Health;
 166     extern "C" IHealth* HIDL_FETCH_IHealth(const char* name) {
 167         const static std::string providedInstance{"default"};
 168         if (providedInstance != name) return nullptr;
 169         return Health::initInstance(&gHealthdConfig).get();
 170     }
 171     ```
 172
 173     ```mk
 174     # device.mk
 175     PRODUCT_PACKAGES += android.hardware.health@2.0-impl-<device>
 176     ```