Embedded System Porting (1)

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Embedded System Porting (1)
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? ?

1. Overview
2. Bootloader
3. Kernel
4. Ramdisk
5. JFFS2

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Overview
4
Overview (1)
Target System

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Overview (2)

• ?? ?? ??
• Target Embedded System? ???? ???? ??? ??? 3??
  ????? ????
• Boot Loader
• ????? ????? kernel image? SDRAM? ???? ??? ????
  ??? ?? ????
• OS Kernel
• OS ? ?? ????
• Root File System
• Kernel ?? ??? File System

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Overview (3)

• ?? ?? ??
• Target System? ?? ????? ???? ?? user file system?
  ?? ? ? ??
• User File System
• Root file system ? ???? ?? utility? data file??
  ?? ????? ??? file system
• ?? ?? ????? ???? ???? ??? ???? ???? ???? ???? ??

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Overview (4)

• Boot Loader ??
• ???? ??? ? ?? ?? ???? ????
• Main Function
• Hardware Initialization
• CPU clock, Memory timing, interrupt, UART, ETC.
• PC? BIOS
• Kernel Load
• ?? ??? RAM? ???? ??.
• Additional Function
• Target board? ??? program? ???? ?? ???
• Download Image to SDRAM
• Serial xmodem, uuencode
• Ethernet tftp, bootp
• Fusing Flash Rom
• Write, Read, Erase, Lock/Unlock

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Overview (5)

• Boot Loader ?? ??

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Overview (6)

• Kernel
• OS? ????? ???? ????
• Process management
• Memory management
• Device management
• Network management
• File System Management
• API (Application Programming Interface)
• ETC.
• Kernel Image
• ???? ?? ??? ????? ???? ?? ???? ?? ??? ??
• ??? Kernel image? boot loader? ?? ??? ????
  SDRAM?? load ??

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Overview (7)

• Root File System
• / ????? ??? ?? ?? ????? ???? ???? ?? ????? ???
  ???? ? ?? ??? ???? ??
• Kernel? ???? ??? ?? ?? Root File System? ?????
• Embedded System? ??? ??? ?? ?? ???? ??????? hard
  disk? ??? ??
• ? ?? ?? ?? Ramdisk? ???? Root File System? ??

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Overview (8)

• Ramdisk
• Hard disk ? floppy disk ? Kernel? ???? ?? File
  System? ?? ?? RAM? ?? ??? ?? ??? ??
• ? RAM? disk ???? ???? ?? Ramdisk? ?
• ??? ramdisk ???? Flash Memory? ??? ? ??? ??? ???
  ??? ram? Load? ? ????
• ?? ??? ??? ? ?? ? ?? ???? static data? ??
• ???? Embedded System? Root File System? ???? ??
  ramdisk? ????

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Overview (9)

• User File System
• Root file system ? ???? ?? utility? data file??
  ?? ????? ??? file system
• ?? ??? ???? target board? ?? ????? ???? ??? ??
• Flash File System?? ??
• Ramdisk? ?? Flash Memory? ?? file system? ??? ?
• Flash Memory? ?? read/write ? hard disk? ???? ??
• ??? ?? ??? ?? ??? Flash Memory? ??
• Flash memory? ???? ?? ??? ???? ???? ??? ??? ????
  ?? ??? ??? ? ??

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Overview (10)

• JFFS2
• Journalling Flash File System
• Red Hat?? ??? flash file system?? linux kernel??
  ??
• ?? NOR Flash Memory? ??
• ??? ????? ???? ?? ?? ??? ?? ?? ????, ramdisk?
  ???? ?? ???? ?? ???? ?? ??

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Overview (11)

• Target System ?? ??

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Overview (12)

• Target System? ?? ??-1
• Boot Loader

SDRAM
Boot Loader Linux Kernel RAMDISK JFFS2
1. Power On
2.Execute 0x00000000
3.Load Kernel
4. Load Root File System (RAMDISK)
FLASH Memory
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Overview (13)

• Target System? ?? ??-2
• Kernel

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Bootloader

• ????? ????? JTAG? ???? flash memory? fusing ??

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Boot Loader ?? (1)

• Boot Loader Compile
• Boot Loader For Xscale processor
• Arm ??? processor??? BLOB? ?? ??
• Boot Loader source code
• HUINS?? ??? CD? blob.zip ??
• Kernel source code
• HUINS?? ??? CD? linux-2.4.19-cd.tar.gz ??
• Install Method
• JTAG ??? ??? ?? ?? ??
• ROM? ?? ???? ???? ??? ??

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Boot Loader ?? (2)

• Boot Loader Compile
• Huins ?? ??? cd-rom? ????? kernel ? blob ??? ???
  ????? ??? ? ??
• Example??? /usr/local/pxa255 ? ??

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Boot Loader ?? (3)

• Boot Loader Compile
• Kernel blob? source code ?? ??

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Boot Loader ?? (4)

• Boot Loader Compile
• ??? ?? blob ? linux-2.4.19-cd ????? ???
• blob ????? ??

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Boot Loader ?? (5)

• Boot Loader Compile
• Makefile ??

?? ?? ?? ?? ??? ????
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Boot Loader ?? (6)

• Boot Loader Compile
• Host IP address ? Target IP address ??
• /usr/local/pxa255/blob/include/blob/main.h? ?? ??
  ??
• ?? ??? ??, blob?? ?? IP ?? ?? ??? ??

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Boot Loader ?? (7)

• Boot Loader Compile
• Compile

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Boot Loader ?? (8)

• Boot Loader Compile
• blob ??? ??
• /usr/local/pxa255/blob/src/blob/ ? ????

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Boot Loader ?? (9)

• Bootloader Download
• JTAG I/F? ???? flash memory? bootloader ????
  fusing??
• blob ???? ?? ??? ??? ? jtag? ????

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Boot Loader ?? (10)

• Bootloader Download
• ??? ?? ??? ?? blob? flash ???? 0??? ??? (??? ?
  ??(? 35? ??)? ???)

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Boot Loader ?? (11)

• Bootloader Download
• minicom? ???? target borad? reset?? boot loader?
  ? ????? ????

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Boot Loader ?? (12)

• Boot Loader Download
• ??? ?? ??? ??? ??? ???.

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Boot Loader ?? (13)

• BLOB? ?? command

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Boot Loader ?? (14)

• BLOB? memory map

SDRAM (128M)
FLASH ROM (32M)
0x01,fff,fff
0x00,480,000
0x00,280,000
0x00,080,000
0x00,040,000
0x00,000,000
0xa7,fff,fff
JFFS2
0xa3,000,000
ramdisk.gz
0xa0,700,000
BLOB main()
0xa0,400,400
BLOB down image
0xa0,300,000
zImage
0xa0,008,000 0x00,000,000
JFFS2 27.5 Mbytes
ramdisk.gz 2 Mbytes
zImage 2 Mbytes
parameter 256 Kbytes
BLOB 256 kbytes
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Kernel
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Kernel (1)
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Kernel (2)

• ?? ??? ?? ??
• ??? ???? ?? ??? ??? ??? ?? ??? ?? ????? ??
• make menuconfig ??? ???? ?? ??? ?? ??? ??
• ?? ???? ?? ??? ??/???? ?? ??? ??? ??

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Kernel (3)

• Character device ? LED GPIO? KEY GPIO ??

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Kernel (4)

• ?? ??? ??? ???? ?? ?? ?? ??? ??
• make clean make dep make bzImage

?? ??? ??
??? ?? ??? ??
??? ???? ??? ??
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Kernel (5)

• ???? ?? ???? /tftpboot ? ??
• tftp? ?? ?? ???? target system? ?????? ??
• cp ./arch/arm/boot/zImage /tftpboot/
• blob?? ??
• minicom? ?? ??
• blob command mode? target system booting

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Kernel (6)

• Blob?? ?? ??? Download

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Kernel (7)

• Blob?? ?? ??? Fusing

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Kernel (8)

• ??? linux kernel? ??

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Kernel (9)

• Linux login