Chapter One: Introduction to Android system porting and driver development

　　Chapter One Introduction to Android system porting and driver development

Core Content Summary:

Android 's system architecture is divided into 4 Tiers:

1) Linux kernel (linux drivers and memory management, process management, power management programs, etc.)

2) code base C + + ( code base written in C + + ,dalivk virtual machine Runtime)

3) Android SDK API( various libraries written in java )

4) application (all applications belong to this layer)

The main work of Android system porting (application porting and system porting):

• Porting Linux drivers;

• Porting the HAL.

To view the Linux kernel version:

Method One: execute the following command on the Linux terminal
Uname-a

Method Two: execute the following command on the Linux terminal
Cat/proc/version

definition rules for Linux kernel version numbers:

• major version number;

• This version number;

• revision version number;

• Fine-tuned version number;

• Special tuning descriptions for specific Linux systems.

Linux device drivers:

A driver is a kind of program that interacts directly with hardware and is responsible for abstracting the hardware.

The hardware of a computer system is mainly composed of CPU, memory and peripherals.

The driver targets the memory and peripherals (internalCPU -integrated memory and peripherals), rather than the CPU cores.

Linux divides memory and peripherals into 3 major categories:

• Character devices (those that must be accessed sequentially in serial order);

• Block devices (can be accessed in any order, in block units);

• Network devices (designed for packet acceptance and delivery, which do not correspond to the node of the file system).

Linux driver:LED driver

LED -Driven code deeds many functions and structures (readl,writel,printk, Miscdevice,module_exit , etc.)

Chapter One: Introduction to Android system porting and driver development