LINUX BOOT PROCEDURE AND BOOTLOADER

1、Home Automation, Networking, and Entertainment LabDept. of Computer Science and Information Engineering National Cheng Kung University, TAIWANLINUX BOOT PROCEDURE AND BOOTLOADERLAB 6Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 2HANELOUTLINE Introdu

2、ction Boot loader U-Boot Kernel INIT LabDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 3HANELIntroductionqAn embedded linux system is typically consist of some software below :Boot loaderKernelInit programYour applicationDepartment of Computer Scienc

3、e and Information EngineeringNational Cheng Kung University, TAIWAN 4HANELBOOT LOADERqBoot loader is a program that :Execute when board power onDetect hareware (if necessary)Initialize hardwareCopy first program, might be : A simple program Bootloader stage N OS kernelTransfer control to it and goqB

4、oot loader is varied from different CPU, different board.Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 5HANELBOOT LOADER Execute when board power onqAny CPU will execute a program at specified address when power onqBoot loader always be placed there

5、Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 6HANELBOOT LOADER Detect HardwareqSearch for attached device on storageMouse on USBetcqUse detected device if needRead configure Department of Computer Science and Information EngineeringNational Cheng K

6、ung University, TAIWAN 7HANELBOOT LOADER Initialize HardwareqSome hardware require default valueStop interruptSet CPU clockConfigure RAM or MMUReset other processor such as DSPDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 8HANELBOOT LOADER Copy Firs

7、t ProgramqA simple programNon-OS programqBootloader stage NBoot loader might have multiple stages, multiple modesqOS kernelLinuxWinCEetcDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 9HANELBOOT LOADER Copy First ProgramStage NqTypical 2 stages in emb

8、edded systemqStage 1Write in assembly language to speed upInitialize hardwareCopy Stage 2 to RAMPrepare stack for Stage 2Jump to Stage 2qStage 2Write in C for more featureInitialize hardwareLoad kernelSend parameter to kernelStart kernelDepartment of Computer Science and Information EngineeringNatio

9、nal Cheng Kung University, TAIWAN 10HANELBOOT LOADER Copy First ProgramMultiple modesqIn order to provide more feature, boot loader might have multiple modesqMode 1: Boot program or kernelCopy program onlyqMode 2: Update utilityRead or kernel via : RS232 : xmodem protocol (Very Slow) Network : Earse

10、 flash and overwrite it with new dataDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 11HANELBOOT LOADER ExampleDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 12HANELBOOT LOADER Transfer Control to It a

11、nd GoqCopy next program to RAMSometimes might execute on ROMqSetup stack for itqSet PC (or jump) to its start addressDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 13HANELU-BootqU-Boot : Universal BootloaderqPortable and easy to port and to debugqSup

12、port many architectures: PPC, ARMs, MIPS, x86, m68k, NIOS, MicroblazeDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 14HANELU-BootSupport listDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 15HANELU-Boo

13、t Instructionsqhelp: print online helpqhelp : show usageqflinfo: print FLASH memory informationqprotect: enable or disable FLASH write protectionqerase: erase FLASH memoryqloadb: loadb binary serial line (kermit mode)qmd: memory displayqcp: memory copyDepartment of Computer Science and Information E

14、ngineeringNational Cheng Kung University, TAIWAN 16HANELKERNELqAfter kernel is loaded and started, kernel will detect and initialize hardwareqAfter everything is done, find root for VFS (Virtual )qThen, search for init, which is the first program in OSInit will be the parent of all other processDepa

15、rtment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 17HANELINITqThe first process in OSqPID = 1Enter ps aux to show all processqTypical operation :Fork shell and execute a scriptMount all Start all deamonWait for user loginqIn embedded system, there are few t

16、ask to do.Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 18HANELLABDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 19HANELLABqLAB 1: Boot loaderqLAB 2: Boot procedureDepartment of Computer Science and

17、Information EngineeringNational Cheng Kung University, TAIWAN 20HANELLAB 1Boot loaderqInstall boardqInstall arm tool-trainqCompile U-BootqInstall JTAG driverqInstall U-BootDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 21HANELLAB 1Install board qInst

18、all J-TAG and COM11 PinDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 22HANELLAB 1 Install arm tool-train Compile U-BootqIn LinuxqDownload cross-3.2.tar.bz2 and u-boot-1.1.4.zipqInstall cross-3.2 to /usr/local/armqExtract U-Boot and compile itqAfter

19、completed, copy u-boot.bin to Windowsmake innokom_configmake CROSS_COMPILE=/usr/local/arm/bin/arm-linux-Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 23HANELLAB 1 Install JTAG driverqIn WindowsqCopy GIVEIO.SYS under CgiveIO folder to C:WINDOWSsystem

20、32driversqClick 新增硬體 in 控制台qSelect 是，我已連接硬體qSelect 新增硬體裝置qSelect 進階選項qSelect (COM / LPT)qClick 從磁片安裝, select giveio.infDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 24HANELLAB 1 Install U-BootqPlace u-boot.bin in the folder where Jen255.exe existedq

21、Execute Jen255.exe and enter u-boot.binqOpen 超級終端機 with baud rate 19200 bps, no flow controlqReset board and see if successDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 25HANELLAB 2qRe-install origin I-BootqModify boot procedureqInstall kernel and D

22、epartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 26HANELLAB 2 Re-install origin I-BootqIn WindowsqExecute Jen255.exe again, but enter bootldr insteadedDepartment of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 27HANELLAB 2 Modify boot procedureqSetup kernel and qUse compiled kernelqModify existed Department of Computer Science and Information EngineeringNational Cheng Kung University, TAIWAN 28HANELLAB 2 Modify boot procedure(cont)qIn Linux, modify boot proceduregzip -d ramdisk.gz# mount sudo mount -o l