立你斯學習記錄

U-boot是基于PowerPC, ARM, MIPS等多種處理器上的bootloader，可以裝載在boot ROM中，用于起始化或者測試硬體，或者用于裝載和執行應用程式。

where we come from

- start from 8xxrom sources

- create PPCBoot project (http://sourceforge.net/projects/ppcboot)

- clean up code

- make it easier to add custom boards

- make it possibile to add other [PowerPC] CPUs

- extend functions, especially:

* Provide extended interface to Linux boot loader

* S-Record download

* network boot

* PCMCIA / CompactFlash / ATA disk /SCSI … boot

- create ARMBoot project (http://sourceforge.net/projects/armboot)

- add other CPU families(starting with ARM)

- create U-Boot project (http://sourceforge.net/projects/u-boot)

Names and Spelling:

檔名以u-boot為開頭，例如

#include

#include

變數名，預編譯常數等都以u_boot或者U_BOOT開頭，例如

U_BOOT_VERSION u_boot_logo

IH_OS_U_BOOT u_boot_hush_start

Versioning:

U-Boot版本資訊由version, sub-version和patchlevel組成。例如”U-Boot-2.34.5”表示version “2”, sub-version “34”, 和patchlevel “4”.對于正式的發布版本來說，patchlevel總為“0”.

Directory Hierarchy:

- board Board dependent files

- common Misc architecture independent functions

- cpu CPU specific files

- 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs

- arm720t Files specific to ARM 720 CPUs

- arm920t Files specific to ARM 920 CPUs

- at91rm9200 Files specific to Atmel AT91RM9200 CPU

- imx Files specific to Freescale MC9328 i.MX CPUs

- s3c24x0 Files specific to Samsung S3C24X0 CPUs

- arm925t Files specific to ARM 925 CPUs

- arm926ejs Files specific to ARM 926 CPUs

- arm1136 Files specific to ARM 1136 CPUs

- i386 Files specific to i386 CPUs

- ixp Files specific to Intel Xscale IXP CPUs

- mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs

- mips Files specific to MIPS CPUs

- mpc5xx Files specific to Freescale MPC5xx CPUs

- mpc5xxx Files specific to Freescale MPC5xxx CPUs

- mpc8xx Files specific to Freescale MPC8xx CPUs

- mpc8220 Files specific to Freescale MPC8220 CPUs

- mpc824x Files specific to Freescale MPC824x CPUs

- mpc8260 Files specific to Freescale MPC8260 CPUs

- nios Files specific to Altera NIOS CPUs

- nios2 Files specific to Altera Nios-II CPUs

- ppc4xx Files specific to AMCC PowerPC 4xx CPUs

- pxa Files specific to Intel Xscale PXA CPUs

- s3c4bb0 Files specific to Samsung S3C44B0 CPUs

- sa1100 Files specific to Intel StrongARM SA1100 CPUs

- disk Code for disk drive partition handling

- doc Documentation

- drivers Commonly used device drivers

- dtt Digital Thermometer and Thermostat drivers

- examples Example code for standalone applications, etc

- include Header Files

- lib_arm File generic to ARM architecture

- lib_generic File generic to all architecture

- lib_i386 File generic to i386 architecture

- lib_m68k File generic to m68k architecture

- lib_mips File generic to MIPS architecture

- lib_nios File generic to NIOS architecture

- lib_ppc File generic to PowerPC architecture

- net Networking code

- post Power On Self Test

- rtc Real Time Clock drivers

- tools Tools to build S-Record or U-Boot images, etc

Software Configuration:

Configuration _OPTIONS_:

由用戶指定，以CONFIG_開頭

Configuration_SETTINGS_:

跟具體硬體相關，以CFG_

對于已經支援的board，已有預設的configuration,故需要直接make即可，make

_config.

Example:

cd u-boot

make TQM82L_config

對于Cogent platform，則需要make cogent_mpc8xx_config.

Configuration Options:

Configuration取決于board和CPU類別，其資訊在include/configs/ .h

中，例如include/configs/TQM823L.h

需要指定如下：

- CPU Types: 例如CONFIG_MPC860

- Board Type: 例如 CONFIG_PCIPPC2

- CPU Module Type:(如果定義了CONFIG_COGENT),例如CONFIG_CMA286_60_OLD

- Motherboard Type:(如果定義了CONFIG_COGENT)例如CONFIG_CMA101

- Motherboard I/O Modules: (如果定義了CONFIG_COGENT),例如CONGIG_

CMA302

- Board flavour

- MPC824x Family Member

- 8xx CPU options

- 859/866/865 CPU options

- Linux Kernel Interface:

- Serial Ports

- Console Interface

- Console Baudrate

- Interrupt driven serial port input

- Console UART Number

- Boot Delay

- Autoboot Command

- Pre-Boot Commands

- Serial Download Echo Mode

- Kgdb Serial Baudrate

- Monitor Functions

- Watchdog

- U-Boot Version

- Real-Time Clock

- Timestamp Support

- Partition Support

- IDE Reset method

- ATAPI support

- LBA48 support

- SCSI support

- NETWORK support(PCI and others)

- USB support

- MMC support

- Journaling Flash filesystem support

- Keyboard support

- Video support

- Keyboard support

- LCD support

- Splash Screen Support

- Gzip compressed BMP image support

- Compression support

- MII/PHY support

- Ethernet address

- IP address

- Server IP address

- Boot Recovery mode

- DHCP Advanded options

- CDP options

- Status LED

- CAN support

- I2C support

- SPI support

- FPGA support

- Configuration management

- Vendor Parameter protection

- Protected RAM

- Error Recovery

- Command Interpreter

- Default Environment

- DataFlash Support

- SystemACE Support

- TFTP Fixed UDP Port

- Show boot progress

Modem Support:

- Modem support enable: CONFIG_MODEM_SUPPORT

- RTS/CTS Flow control enable: CONFIG_HWFLOW

- Modem debug support

- Interrupt support(PPC): interrupt_init()和timer_interrupt()對于所有PPC架構來說都是通用的。其中，interrupt_init()呼叫interrupt_init_cpu()對特定CPU進行起始化。在interrupt_init_cpu()中，應設定合適的decrement_count值。timer_interrupt()呼叫timer_interrupt_cpu()處理特定的CPU定時。如果板上有watchdog/status_led等，在timer_interrupt()后有效。

- General

Configuration Settings:

- CFG_LONGHELP

- CFG_PROMPT

- CFG_CBSIZE

- CFG_PBSIZE

- CFG_MAXARGS

- CFG_BARGSIZE

- CFG_BAUDRATE_TABLE

- CFG_CONSOLE_INFO_QUITE

- CFG_CONSOLE_IS_IN_ENV

- CFG_CONSOLE_ENV_OVERWRITE

- CFG_MEMTEST_START, CFG_MEMTEST_END

- CFG_ALT_MEMTEST

- CFG_MEMTEST_SCRATCH

- CFG_TFTP_LOADADDR

- CFG_LOADS_BAUD_CHANGE

- CFG_SDRAM_BASE

- CFG_MBIO_BASE

- CFG_FLASH_BASE

- CFG_MONITOR_BASE

- CFG_MONITOR_LEN

- CFG_MALLOC_LEN

- CFG_BOOTMAPSZ

- CFG_MAX_FLASH_BANKS

- CFG_MAX_FLASH_SECT

- CFG_FLASH_ERASE_TOUT

- CFG_FLASH_WRITE_TOUT

- CFG_FLASH_LOCK_TOUT

- CFG_FLASH_UNLOCK_TOUT

- CFG_FLASH_PROTECTION

- CFG_DIRECT_FLASH_TFTP

- CFG_FLASH_CFI

- CFG_FLASH_CFI_DRIVER

- CFG_FLASH_QUIET_TEST

- CFG_RX_ETH_BUFFER

- CFG_ENV_IS_IN_FLASH

- CFG_ENV_IS_IN_NVRAM

- CFG_ENV_IS_IN_EEPROM

- CFG_ENV_IS_IN_NAND

- CFG_SPI_INIT_OFFSET

- CFG_FAULT_ECHO_LINK_DOWN

Low Level (hardware related) configuration options:

- CFG_CACHELINE_SIZE

- CFG_DEFAULT_IMMR

- Floppy Disk Support

- CFG_IMMR: Internal Memory的實體位址

- CFG_INIT_RAM_ADDR：可用于初時資料或堆疊的儲存起始位址

- CFG_GBL_DATA_OFFSET：在由CFG_INIT_RAM_ADDR定義的記憶體中起始化資料的偏移

- CFG_SIUMCR：SIU Module Configuration

- CFG_SYPCR：System Protection Control

- CFG_TBSCR：Time Base Status and Control

- CFG_PISCR：Periodic interrupt status and control

- CFG_PLPRCR：PLL, Low-Power, and Reset Control Register

- CFG_SCCR：System Clock and reset Control Register

- CFG_OR_TIMING_SDRAM

- CFG_MAMR_PTA

- CFG_DER：Debug event register

- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,

- CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM, CFG_BR1_PRELIM：Memory Controller Definitions：BR0/1 and OR0/1(FLASH)

- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,

CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,

CFG_OR3_PRELIM, CFG_BR3_PRELIM：Memory Controller Definitions：BR2/3 and OR2/3(SDRAM)

- CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K, CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL：Machine Mode Register and Memory Periodic Timer Prescaler definitions（SDRAM timing）

- CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]

- CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:

- CFG_USE_OSCCLK

- CFG_CPM_POST_WORD_ADDR,CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB, CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL, CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,CFG_CPU_PCI_MEM_START,CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB, CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL, CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE, CFG_POCMR2_MASK_ATTRIB

- CONFIG_ETHER_ON_FEC

- CONFIG_FEC[12]_PHY

- CONFIG_FEC[12]_PHY_NORXERR

- CONFIG_RMII

- CONFIG_CRC32_VERIFY

- CONFIG_LOOPW

- CONFIG_MX_CYCLIC

- CONFIG_SKIP_LOWLEVEL_INIT

CONFIG_SKIP_RELOCATE_UBOOT

Buildin the Software:

U-BOOT已經在native PPC環境和交叉環境中測試過，包括在LinuxPPC 2000, RedHat Linux on x86, Solaries 2.6 on SPARC及NetBSD 1.5 on x86。如果不是使用native PPC environment，那么則需要具有交叉編譯工具如前置“powerpc-linux-”等編譯器，鏈結器，elf檔案解析器等工具。這是需要重新定義Makefile中的CROSS_COMPILE。例如：CROSS_COMPILE = ppc_4xx-，此外，還需要制定U-Boot為特定的board type。

make NAME_CONFIG

最后，執行

make all

來生成U-Boot images。生成的image包括：

u-boot.bin 是raw binary image

u-boot 是ELF格式的image

u-boot.srec 是Motorola(FreeScale)的s-records format

此外，還需要注意，與GNU mkae不同，在NetBSD下應該使用"gmake"

U-Boot的移植

如果使用的platform不存在，則需要將U-BOOT進行移植。步驟如下：

（1） 為使用的board為Makefile和MAKEALL添加新的configuration option。

（2） 為使用的board新建一個新的目錄，該目錄下至少應該包含“Makefile”

“ .c”和“flash.c”及“u-boot.lds”

（3） 執行“make _config”

（4） 執行“make”，則會生成“u-boot.srec” image

（5） Debug and test