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Development of Mobile Linux Open Platform Development of ...

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  • 1. Development of Mobile Linux Open Platform April 16, 2008 Jyunji Kondo Fujitsu Software Technologies Limited
  • 2. Ideas Application Emulator Application Real Hardware package package (.apk) (.apk) extract extract Dalvik Dalvik Class Class byte code byte code libraries libraries (.dex) (.dex) convert convert convert convert CPU native CPU native CPU nativecode CPU nativecode code (ARMv5) code (ARMv5) (ARMv5) linkage (ARMv5) linkage Dalvik VM(ARMv5) Dalvik VM(ARMv5) Linux kernel Linux kernel (ARMv5+BSP) (ex. i.MX31) Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 3. Main thesis “It's not so difficult to just enable functions of Android using well-maintained well- Linux BSP!” Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 4. Real Hardwares i.MX31 Product Development Kit Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 5. Topics 1. input device 2. sound 3. power management 4. telephony Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 6. Input device “If Linux BSP supports keyboards, mice, and touch screens as input device, Android can handle those.” Facts: Android emulator supports keyboards and mice. Internals: Android watch all files under /dev/input/. Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 7. Input device “If Linux BSP supports keyboards, mice, and touch screens as input device, Android can handle those.” Hypothesis: Touch screens can be handled with event interface of input device. Result: Achieved with small modification of input driver. Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 8. Input device “If Linux BSP supports keyboards, mice, and touch screens as input device, Android can handle those.” How: • changing X-Y coordinate • X, Y direction • resolution • changing event type • EV_ABS/ABS_PRESSURE → EV_KEY/BTN_TOUCH Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 9. Sound “If Linux BSP supports ALSA driver, Android can play musics.” musics.” Facts: Android emulator can play music on PC. Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 10. Sound “If Linux BSP supports ALSA driver, Android can play musics.” musics.” Hypothesis: Internals: MP3/3GPP Android MediaPlayer API PCM PCM Linux EAC driver kernel PCM ALSA driver (ex. pcmC0D0p) PCM pseudo H/W (SDMA) Emulator real H/W (PMIC) Real Host PC’s sound driver Hardware Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 11. Power management “If Linux BSP supports to control CPU clock and backlight brightness, brightness, power management of android can be supported.” Facts: Android provides 2 lock types • partial wake lock • full wake lock Android also control backlight brightness Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 12. Power management “If Linux BSP supports to control CPU clock and backlight brightness, brightness, power management of android can be supported.” Internals: Android operates sysfs files •/sys/android_power/acquire_full_wake_lock •/sys/android_power/acquire_partial_wake_lock •/sys/class/leds/keyboard-backlight/brightness •/sys/class/leds/lcd-backlight/brightness •/sys/class/leds/button-backlight/brightness Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 13. Power management “If Linux BSP supports to control CPU clock and backlight brightness, brightness, power management of android can be supported.” Hypothesis: Internals: wake lock acquire/release Android PowerManager API Linux android power driver DPM kernel leds class Real Emulator real H/W (CPU/IPU) Hardware Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 14. Power management “If Linux BSP supports to control CPU clock and backlight brightness, brightness, power management of android can be supported.” How: • CPU freq • defines 4 OPs and policies • 532M, 399M, 266M, 133M • throttle down every 3 seconds during no activities • LCD backlight • become darker every 15 seconds. Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 15. Telephony “If Linux BSP can control baseband with serial I/F, you can make a phone call with android.” Facts: • Android emulator supports a pseudo GSM modem device. •There is the rild (Radio I/F Layer Daemon). Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 16. Telephony “If Linux BSP can control baseband with serial I/F, you can make a phone call with android.” Hypothesis: Internals: Android Android rild libreference-ril.so VT wsimd modem (GSM) Linux serial driver kernel android modem W-SIM Real Emulator (pseudo GSM) (PHS) Hardware Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 17. Conclusion “It's not so difficult to just enable functions of Android using well-maintained well- Linux BSP!” Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED
  • 18. Copyright 2008 FUJITSU SOFTWARE TECHNOGIES LIMITED