Bootloader Porting

1
Bootloader Porting

• Lecture 6

2
? ?

• ???? ??
• u-boot ????? ?? ??
• u-boot ?? ??
• u-boot ??
• ???? fusing??
• u-boot ???

3
???? ?? (1)

• ??
• ???? ????? ????? ????? ??? ???? ????? ??? ????
• ????? ??? ??
• ????? ??? ???? ?? ?? 0??? ??
• 0x0000_0000 Reset exception
• ????? ?? ?? Startup, Monitoring mode, OS Boot
• ???? ???
• Clock ??, memory(SDRAM) ??, ???? disable
• ????? ???
• ???? ???
• ??? root filesystem ??
• ??? root file system? ???? ???? Linux ??

4
???? ?? (2)

• u-boot ??
• Universal Bootloader
• ppcboot armboot
• PPC? ARM? ??? ? ????? Bootloader
• ??? cpu ?? (PPC, ARM, MIPS, SH, x86)
• Open Source

5
u-boot ????? ?? ?? (1)
???? ??
board ?? evaluation ??? ??? ??
board/pro3 pro3??? ??? ??
common architecture ???? ??
cpu architecture? ???? ?? ??? cpu? ?? startup ??, serial, clock ? cpu specific? ???? ??
cpu/pxa pro3?? ???? XScale?? ?? ??
disk ??? ????? ??? ?? ??
doc u-boot ??? ??
drivers ????? ???? ??
examples u-boot? ?? test ?? ??
include header file
include/config ?? ??? ?? header file
net Network ?? ??
post Power On Self Test
rtc Real Time Clock driver ??
tools U-boot ???? S-Record ???? ???? ?? tool (mkimage)
6
u-boot ????? ?? ?? (2)
???? ???? ???? ??
include asm/arch-pxa/ asm/arch-pxa/ pxa2xx? ?? ????
include configs pro3.h ??? ???? ??? ??, ??? ???? ? ????? ??, ?? ?? ?? ??
cpu pxa start.S u-boot?? ?? ?? ???? ???? exception table? ???.
cpu pxa interrupt.c ????? ?????? ?? ??
cpu pxa serial.c ??? ??(uart)? ???? ????? ??? ?? ??
cpu pxa cpu.c ?? ??, ????? ?? ? cpu? ??
board pro3 config.mk u-boot? ??? ??? ??? ?? ??? ????
board pro3 u-boot.lds u-boot? ??? ??? ?? ?? ????
board pro3 pro3.c pro3 ?? ??
board pro3 flash.c ??? ???? ??
drivers smc91111.c smc91111.h smc91111.c smc91111.h smc91111 Ethernet driver
7
u-boot? ?? ?? (1)

• ????? ?? ??

8
u-boot ?? ?? (2)

• start.S

9
u-boot ?? ?? (3)

• Memory ??

0x0200_0000
u-boot
0xA7F8_0000
root f/s
0x0030_0000
uImage
0x0008_0000
Bootloader parameters
0x0004_0000
u-boot
0x0000_0000
FLASH
0xA000_0000
Memory
10
u-boot ?? ?? (4)

• u-boot ?? ??

ASM startup?? (cpu/pxa/start.S)
cpu ???, sdram???, sdram?? relocation,
start_armboot()??
C?? start_armboot() (lib_arm/board.c)
flash_init, eth_init console ???
main_loop() (common/main.c)
??? ?? ?? autoboot
Linux booting (lib_arm/armlinux.c)
Linux booting (??? ??? ??? ?? ?? ???? ???? ??)
11
Linux? ?? boot ?? (1)

• Linux booting? ??? ??? ???
• Linux Kernel image
• FLASH/ROM?? ???? ?? Kernel? ??
• Root File System(RFS) image
• Jffs2 image, RAMdisk
• ???? boot-loaders? ??? ? ?? ????? ??
• Bootloading Local Booting
• ????? Kernel? RFS? ?? device(Flash)???
  load??(autoboot).
• Downloading Remote Booting
• Kernel? RFS? ?? device(Host PC)??? download
• ???? Kernel? RFS? install?? ?? ? ??? ??
• ?? ??? updates? ?? ??

12
Linux? ?? boot ?? (2)

• Linux kernel? ???? ??? ?? bootloader?? ?? ? ? (1)
• Initialize base hardware
• CPU speed
• memory timings
• Detect machine type (passed to Kernel by r1)
• Initialize device
• Init UART to be Kernel console
• (passed to Kernel by tagged list, kernel boot
  option)
• Copy Kernel and RFS image to RAM
• Kernel? ?? ??? physical memory? ??? ????. ?? RFS?
  ?? memory? ???? (??? ??? ??).
• Copy (?? download) ? ?? Kernel? RFS? ??? ??? ???
  ??? ??.
• Setup the Kernel Tagged List (?? ??)
• ppc structure
• arm physical ram ???? 0x100 (0xA000_0100)

13
Linux? ?? boot ?? (3)

• Linux kernel? ???? ??? ?? bootloader?? ?? ? ? (2)
• Calling the Linux Kernel with following settings
• CPU register settings
• R0 0,
• R1 machine architecture number (the
  MACH_TYPE_XXX in kernel) (linux/include/asm/ma
  ch-types.h)
• Linux/arch/arm/tools/mach-types? ?? ???? ??.
• R2 base address of ATAG list
• (system RAM?? ?? tagged list? physical address)
• CPU mode
• All forms of interrupts must be disabled (IRQs,
  FIQs)
• CPU must be in SVC mode
• Cache, MMU
• MMU mustbe off
• D-cache must be off and no any stale data
  (I-Cache can be on/off)

14
Linux? ?? boot ?? (4)

• R0, R1, R2 ????? ???? ??? ???? ??
• void do_bootm_linux()
• void (theKernel)(int zero, int arch, uint
  params)
• ..
• theKernel (void ()(int, int,
  uint))ntohl(hdr-gtih_ep)
• ..
• theKernel (0, bd-gtbi_arch_number,
  bd-gtbi_boot_params)
• u-boot/board/pro3/pro3.c
• gd-gtbd-gtbi_arch_number 8894
• linux/arch/arm/tools/mach-types
• pro3 ARCH_PRO3 PRO3 8894
• u-boot/board/pro3/pro3.c
• gd-gtbd-gtbi_boot_params 0xa0000100 // address
  of boot parameters

u-boot/lib-arm/armlinux.c
15
u-boot ??

• ???? ??? ?? ??
• cd /root/pro3/Bootloader
• ls
• tar xfz ./u-boot-1.2.0-pro3-YYYYMMDD.tar.gz
• ???? ??? ??
• cd ./u-boot-1.2.0-pro3
• make pro3_config
• make
• ls ./u-boot.bin
• cp ./u-boot.bin /tftpboot

16
???? fusing??

• ?????? Host PC? Targetboard IP? ??? ?? tftp? ??
  ???? ???? ? ? ??.
• // Host PC? Targetboard? IP? ????
• PRO3gt set serverip 192.168.1.10
  ? host pc ip
• PRO3gt set ipaddr 192.168.1.20 ?
  targetboard ip
• // u-boot image ?? ?? ? fusing
• PRO3gt set boot_file ./pxa255_pro3/u-boot.bin
• PRO3gt run bootf

17
u-boot ???

• cmp ??? ??
• cp ??? ??
• erase flash ??? ??
• flinfo flash ??? ?? ??
• go addr ???? ??
• help ??? ??
• md ??? ??
• mm ??? ??
• mtest ?? RAM ???
• mw ??? ??
• printenv ?? ?? ??
• run ?? ??? ???? ???
• saveenv ????? ?? ?? ??
• setenv ?? ?? ??