"Android Linux kernel" vs "standard Linux kernel"

The Linux kernel of Android is stored in the kernel subdirectory. By comparing it with the standard Linux 2.6.25 kernel, we can find that it mainly adds the following content:

1. Add the gold-fish platform based on the ARM architecture. The directories added are as follows:

Kernel/ARCH/ARM/Mach-goldfish

Kernel/include/ASM-arm/arch-goldfish
The gold-fish platform uses arm926t CPU as the baseband processor. The CPU clock speed is at least 200 m Hz. The msm7201a CPU (arm 11) is used as the main CPU, and the clock speed is 528 M Hz.

2. added the yaffs2 FLASH file system and added the following directories:

Kernel/fs/yaffs2

In fact, the system. IMG and ramdisk. imgfiles generated after the android package is compiled are in the yaffs2 format.

3. added the android driver. The corresponding directory is:
Kernel/Drivers/android

Mainly divided:
Android IPC: binder
Android log system: Logger

Android power management: Power

Android alarm management: Alarm
Android memory Console: ram_console
Gpio controlled by Android clock: timed_gpio
4. Added switch processing. The corresponding directory is:
Kernel/Drivers/switch/
5. A new shared memory processing method is added, and the corresponding files are:
Kernel/MM/ashmem. c

6. Other patches for the Linux-2.6.25 kernel, such as Bluetooth, are not analyzed in detail here

In addition, the driver files related to the goldfish platform are as follows:
1. character output device:
Kernel/Drivers/Char/goldfish_tty.c
2. Image Display Device: (frame buffer)
Kernel/Drivers/Video/goldfishfb. c
3. keyboard input device:
Kernel/Drivers/input/keyboard/goldfish_events.c
4. RTC device: (real time clock)
Kernel/Drivers/RTC/rtc-goldfish.c
5. USB device:
Kernel/Drivers/USB/gadget/android_adb.c
6. SD card device:
Kernel/Drivers/MMC/host/goldfish. c

7. Flash devices:
Kernel/Drivers/MTD/devices/goldfish_nand.c
Kernel/Drivers/MTD/devices/goldfish_nand_reg.h
8. LED device:
Kernel/Drivers/LEDs/ledtrig-sleep.c
9. Power supply device:
Kernel/Drivers/power/goldfish_battery.c
10. audio device:
Kernel/ARCH/ARM/Mach-goldfish/audio. c
11. Power Management:
Kernel/ARCH/ARM/Mach-goldfish/PM. c
12. Clock management:
Kernel/ARCH/ARM/Mach-goldfish/Timer. c