需要准备的有：TQ2440目标板，ELDK-5.1编译器，u-boot-2011.06
1.我的 u-boot-2011.06.tar.bz2 放在共享文件夹中，工作目录在 /home/huwei/uboot/ 下，因此解压到这个文件夹：tar jxvf u-boot-2011.06.tar.bz2 /home/huwei/uboot/ ；
2.接下来搭建针对硬件的 u-boot 框架，进入 u-boot 代码文件夹 cd /home/huwei/uboot/u-boot-2011.06/ ：
??? A.cp include/configs/smdk2410.h include/configs/tq2440.h
????B.cp -r board/samsung/smdk2410 board/samsung/tq2440
????C.mv board/samsung/tq2440/smdk2410.c board/samsung/tq2440/tq2440.c????
????D.修改 u-boot 顶层的 Makefile 文件：gedit /home/huwei/uboot/u-boot-2011.06/Makefile ，第28行COBJS:=smdk2410.o 改为 COBJS:=tq2440.o ，保存并退出
????E.配置板子信息，gedit /home/huwei/uboot/u-boot-2011.06/boards.cfg，找到smdk2410，在第70行加入板子名为 tq2440?的信息，即：tq2440 arm arm920t - samsung s3c24x0 ，保存并退出。这样做了就不需要再去顶层 Makefile 中加入 tq2440_config: unconfig 的编译配置信息了。
??? 可以验证一下：make CROSS_COMPILE=arm-linux-gnueabi- clean
????????????????? make CROSS_COMPILE=arm-linux-gnueabi-?tq2440_config
????????????????? make CROSS_COMPILE=arm-linux-gnueabi-?all
????在顶层生成了 u-boot.bin 说明 OK。
3.下面开始 NOR FLASH 启动的移植。
??? A.修改板子配置头文件的宏定义：
????? gedit /home/huwei/uboot/u-boot-2011.06/include/configs/tq2440.h
????? 第38行，#define CONFIG_S3C2410 改为 #define CONFIG_S3C2440 ，通知编译器目标处理器是 S3C2440??????
????? 第131行，#define CONFIG_SYS_PROMPT "SMDK2410 #" 改为 #define CONFIG_SYS_PROMPT "TQ2440 #"，目的是在控制台命令行开头提示符显示为 TQ2440 #
????? 第185行，#define CONFIG_FLASH_CFI_LEGACY 改为 #define CONFIG_SYS_CFI_FLASH_CONFIG_REGS
{0xFFFF}，由于 u-boot-2011.06 里 NOR FLASH 使用的是 CFI 接口，因此不需要定义 CONFIG_FLASH_CFI_LEGACY ，而是要定义 CONFIG_SYS_CFI_FLASH_CONFIG_REGS
??????第191行，#define CONFIG_SYS_MAX_FLASH_SECT (19)?改为 #define CONFIG_SYS_MAX_FLASH_SECT
(19)，因为开发板使用的 NOR FLASH 的型号是 EN29LV160AB ，有35个扇区
??????第212行，#define CONFIG_NAND_S3C2410?改为 #define CONFIG_NAND_S3C2440，因为开发板使用的 NOR FLASH 的型号是 EN29LV160AB ，有35个扇区
??????第213行，#define CONFIG_SYS_S3C2410_NAND_HWECC?改为 #define CONFIG_SYS_S3C2440_NAND_HWECC
4.修改时钟频率.
????? A.gedit /home/huwei/uboot/u-boot-2011.06/arch/arm/cpu/arm920t/start.s
????????? 第164行，# if defined(CONFIG_S3C2410)?改为 # if defined(CONFIG_S3C2440)
????????? 第165行，ldr r1,=0x3ff?改为 ldr r1,=7fff，因为 S3C2440 的 INTMASK 有15位，目的是屏蔽所有子中断
????????? 第173行，mov r1,#3 改为 mov r1,#5，目的是目的是使 FCLK:HCLK:PCLK = 1:4:8??????
????? B.gedit /home/huwei/uboot/u-boot-2011.06/board/samsung/tq2440/tq2440.c
????????? 第42至44行，改为：
????????????? #define M_MDIV 92
????????????? #define M_PDIV 1
????????????? #define M_SDIV 1
??????????因为开发板输入晶振是12Mhz，通过修改，可以使 MPLL 的频率为 400MHz
??????????第54至56行，改为：
????????????? #define U_M_MDIV 56
????????????? #define U_M_PDIV 2
????????????? #define U_M_SDIV 2
????????? 通过修改，可以使 UPLL 的频率为 48MHz
5.修改 SDRAM 时序，gedit /home/huwei/uboot/u-boot-2011.06/board/samsung/tq2440/lowlevel_init.s
??? 第54至126行，改为：
??????? #define B1_BWSCON (DW16)
??????? #define B2_BWSCON (DW16)
??????? #define B3_BWSCON (DW16)
??????? #define B4_BWSCON (DW32)
??????? #define B5_BWSCON (DW16)
??????? #define B6_BWSCON (DW32)
??????? #define B7_BWSCON (DW32)
??????? /* BANK0CON */
??????? #define B0_Tacs 0x3
??????? #define B0_Tcos 0x3
??????? #define B0_Tacc 0x7
??????? #define B0_Tcoh 0x3
??????? #define B0_Tah 0x3
??????? #define B0_Tacp 0x1
??????? #define B0_PMC 0x0
??????? /* BANK1CON */
??????? #define B1_Tacs 0x1
??????? #define B1_Tcos 0x1
??????? #define B1_Tacc 0x6
??????? #define B1_Tcoh 0x1
??????? #define B1_Tah? 0x1
??????? #define B1_Tacp 0x0
??????? #define B1_PMC? 0x0
?
?? ???? #define B2_Tacs 0x1
??????? #define B2_Tcos 0x1
??????? #define B2_Tacc 0x6
??????? #define B2_Tcoh 0x1
??????? #define B2_Tah? 0x1
??????? #define B2_Tacp 0x0
??????? #define B2_PMC? 0x0
??????? #define B3_Tacs 0x1
??????? #define B3_Tcos 0x1
??????? #define B3_Tacc 0x6
??????? #define B3_Tcoh 0x1
??????? #define B3_Tah? 0x1
??????? #define B3_Tacp 0x0
??????? #define B3_PMC? 0x0
??????? #define B4_Tacs 0x1
??????? #define B4_Tcos 0x1
??????? #define B4_Tacc 0x6
??????? #define B4_Tcoh 0x1
??????? #define B4_Tah? 0x1
??????? #define B4_Tacp 0x0
??????? #define B4_PMC? 0x0
??????? #define B5_Tacs 0x1
??????? #define B5_Tcos 0x1
??????? #define B5_Tacc 0x6
??????? #define B5_Tcoh 0x1
??????? #define B5_Tah? 0x1
??????? #define B5_Tacp 0x0
??????? #define B5_PMC? 0x0
??????? #define B6_MT?? 0x3
??????? #define B6_Trcd 0x3
??????? #define B6_SCAN 0x1
??????? #define B7_MT?? 0x3
??????? #define B7_Trcd 0x1
??????? #define B7_SCAN 0x1
??????? /* REFRESH parameter */
??????? #define REFEN? 0x1
??????? #define TREFMD 0x0
??????? #define Trp??? 0x1
??????? #define Trc??? 0x1
??????? #define Tchr???0x2
??????? #define REFCNT 1268
6.修改 NAND FLASH 相关内容，目的只是使编译通过，虽然至此还未使用到 NAND FLASH
??? A.cp /home/huwei/uboot/u-boot-2011.06/drivers/mtd/nand/s3c2410_nand.c /home/huwei/uboot/u-boot-2011.06/drivers/mtd/nand/s3c2440_nand.c
????B.gedit /home/huwei/uboot/u-boot-2011.06/drivers/mtd/nand/s3c2440_nand.c
??????? 将代码中所有的 S3C2410 改为 S3C2440
????C.gedit /home/huwei/uboot/u-boot-2011.06/drivers/mtd/nand/Makefile
??????? 第48行，COBJS-$(CONFIG_NAND_S3C2410) += s3c2410_nand.o 改为 COBJS-$(CONFIG_NAND_S3C2440) += s3c2440_nand.o
????D.编译 u-boot 并烧到 NOR FLASH ，上电运行，打印如下信息：
??????? U-Boot 2011.06 (Jul 30 2011 - 23:40:44)
????????DRAM: 64 MiB
?????? ?Flash: 2 MiB
????????NAND: raise: Signal # 8 caught
??????? raise: Signal # 8 caught
??????? raise: Signal # 8 caught
??????? raise: Signal # 8 caught
??????? raise: Signal # 8 caught
??????? raise: Signal # 8 caught
??????? No NAND device found!!!
??????? 0 MiB
??????? *** Warning - bad CRC,using defaultenvironment
??????? In: serial
??????? Out: serial
??????? Err: serial
??????? Net: CS8900-0
??????? TQ2440 #
??? 可以看到一些信息：DRAM 为 64MB ，NOR FLASH 为 2MB ，由于并未设置 NAND FLASH ，因此系统没有检测到 NAND FLASH ，此外，命令行提示符也已经改为 TQ2440 # ，如果使用命令 flinfo ，则更多 NOR FLASH 的信息会显示出来。
7.实现 NAND FLASH 的读写。
??? 在上一步中，只是把 /home/huwei/u-boot-2011.06/drivers/mtd/nand/s3c2410_nand.c 复制 为 s3c2440_nand.c 并将所有 s3c2410 都改为了 s3c2440 ，但这么做只是为了使编译通过，并没有实现对 NAND FLASH 的读写。S3C2410 的 NAND FLASH 控制器跟 S3C2440 的不太一样，因此 s3c2440_nand.c 并不能直接应用，需要修改相关寄存器。
????A.重新定义要用到的寄存器
??????? 第27至37行，去掉之后改为如下内容：
??????????? #define S3C2440_NFCONT_SECCL???? (1<<6)
??????????? #define S3C2440_NFCONT_MECCL???? (1<<5)
??????????? #define S3C2440_NFCONT_INITECC?? (1<<4)
??????????? #define S3C2440_NFCONT_nCE?????? (1<<1)
??????????? #define S3C2440_NFCONT_MODE????? (1<<0)
??????????? #define S3C2440_NFCONF_TACLS(x)? ((x)<<12)
??????????? #define S3C2440_NFCONF_TWRPH0(x) ((x)<<8)
??????????? #define S3C2440_NFCONF_TWRPH1(x) ((x)<<4)
??????????? #define S3C2440_ADDR_NALE 0x08
??????????? #define S3C2440_ADDR_NCLE 0x0C
????B.修改 board_nand_init 和 s3c2440_hwcontrol 这2个函数，其他不变
??????? board_nand_init 函数主要是对 NAND FLASH 的初始化，修改它的 NANDCONF 和 NANDCONT 寄存器，下面红色字体表示修改的地方：
??????? int board_nand_init(struct nand_chip *nand)
??????? {
??????????? u_int32_t cfg;
??????????? u_int8_t tacls,twrph0,twrph1;
??????????? struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
??????????? struct s3c2440_nand *nand_reg = s3c2440_get_base_nand();
????????
??????????? debugX(1,"board_nand_init()n");
????????????
??????????? writel(readl(&clk_power->clkcon) | (1 << 4),&clk_power->clkcon);
??????????? /* initialize hardware */
??????????? #if defined(CONFIG_S3C24XX_CUSTOM_NAND_TIMING)
??????????????? tacls? = CONFIG_S3C24XX_TACLS;
??????????????? twrph0 = CONFIG_S3C24XX_TWRPH0;
??????????????? twrph1 =? CONFIG_S3C24XX_TWRPH1;
??????????? #else
??????????????? tacls = 2;
??????????????? twrph0 = 5;
??????????????? twrph1 = 1;
??????????? #endif
???????????????? cfg? = S3C2440_NFCONF_TACLS(tacls - 1);
???????????????? cfg |= S3C2440_NFCONF_TWRPH0(twrph0 - 1);
???????????????? cfg |= S3C2440_NFCONF_TWRPH1(twrph1 - 1);
???????????????? writel(cfg,&nand_reg->nfconf);
?????????????????
???????????????? cfg? = S3C2440_NFCONT_SECCL;
???????????????? cfg |= S3C2440_NFCONT_MECCL;
???????????????? cfg |= S3C2440_NFCONT_MODE;
???????????????? cfg |= S3C2440_NFCONT_INITECC;
???????????????? writel(cfg,&nand_reg->nfcont);??? // 注意是 nfcont ，不是 conf
?????????????????
???????????????? /* initialize nand_chip data structure */
???????????????? nand->IO_ADDR_R = (void *)&nand_reg->nfdata;
???????????????? nand->IO_ADDR_W = (void *)&nand_reg->nfdata;
???????????????? nand->select_chip = NULL;
?????????????????
???????????????? /* read_buf and write_buf are default */
???????????????? /* read_byte and write_byte are default */
??????????????? #ifdef CONFIG_NAND_SPL
??????????????????? nand->read_buf = nand_read_buf;
??????????????? #endif
?????????????????
???????????????? /* hwcontrol always must be implemented */
???????????????? nand->cmd_ctrl = s3c2440_hwcontrol;
?????????????????
???????????????? nand->dev_ready = s3c2440_dev_ready;
?????????????????
??????????? #ifdef CONFIG_S3C2440_NAND_HWECC
??????????????? nand->ecc.hwctl = s3c2440_nand_enable_hwecc;
??????????????? nand->ecc.calculate = s3c2440_nand_calculate_ecc;
??????????????? nand->ecc.correct = s3c2440_nand_correct_data;
??????????????? nand->ecc.mode = NAND_ECC_HW;
??????????????? nand->ecc.size = CONFIG_SYS_NAND_ECCSIZE;
??????????????? nand->ecc.bytes = CONFIG_SYS_NAND_ECCBYTES;
??????????? #else
??????????????? nand->ecc.mode = NAND_ECC_SOFT;
????????????#endif
????????????
??????????? #ifdef CONFIG_S3C2440_NAND_BBT
??????????????? nand->options = NAND_USE_FLASH_BBT;
??????????? #else
??????????????? nand->options = 0;
??????????? #endif
????????????
??????????????? debugX(1,"end of nand_initn");
??????????????? return 0;
??????????? }
??????? 接着修改 s3c2440_hwcontrol 函数，它用于对 NAND FLASH 写地址和写命令操作
??????????? static void s3c2440_hwcontrol(struct mtd_info *mtd,int cmd,unsigned int ctrl)
??????????? {
??????????????? struct nand_chip *chip = mtd->priv;
??????????????? struct s3c2440_nand *nand = s3c2440_get_base_nand();
????????????????
??????????????? debugX(1,"hwcontrol(): 0x%02x 0x%02xn",cmd,ctrl);
????????????????
??????????????? if (ctrl & NAND_CTRL_CHANGE) {
??????????????????? ulong IO_ADDR_W = (ulong)nand;
??????????????? if (!(ctrl & NAND_CLE))
??????????????????? IO_ADDR_W |= S3C2440_ADDR_NCLE;
??????????????? if (!(ctrl & NAND_ALE))
??????????????????? IO_ADDR_W |= S3C2440_ADDR_NALE;
??????????????? if (cmd == NAND_CMD_NONE)
??????????????????? IO_ADDR_W? = &nand->nfdata;
??????????????????? chip->IO_ADDR_W = (void *)IO_ADDR_W;
??????????????? if (ctrl & NAND_NCE)
??????????????????? writel(readl(&nand->nfconf) & ~S3C2440_NFCONT_nCE,
??????????????????????? &nand->nfconf);
??????????????? else
??????????????????? writel(readl(&nand->nfconf) | S3C2440_NFCONT_nCE,
??????????????????????? &nand->nfconf);
????????????}
????????????if (cmd != NAND_CMD_NONE)
??????????????? writeb(cmd,chip->IO_ADDR_W);
??????? }
????????这么做，除了修改寄存器的值以及设置写地址和写命令的 I/O 端口外，还增加了 if(cmd == NAND_CMD_NONE) 这个判断语句，不加会导致无法向 NAND FLASH 写数据，尽管系统不会提示任何错误并显示 “OK”?，这么做是因为写完地址和命令后，一定还要把 I/O 端口地址重新设置为寄存器 NFDATA 。
??????? 由于系统没有定义 CONFIG_S3C2410_NAND_HWECC,因 此 我 们 暂 时 先 不 对 s3c2440_nand_enable_hwecc 函 数 、s3c2440_nand_calculate_ecc 函数和 s3c2440_nand_correct_data 函数进行修改。
????编译后烧写 u-boot.bin 到 NOR FLASH ，打印信息如下：
??? U-Boot2011.06 (Aug 10 2011 - 23:16:25)
??? DRAM: 64 MiB
??? Flash: 2MiB
??? NAND: 256 MiB
??? ***Warning - bad CRC,using default environment
??? In:? serial
??? Out: serial
??? Err: serial
??? Net: CS8900-0
??? TQ2440# nand info
??? Device 0:nand0,sector size 128 KiB
??? TQ2440# nand device 0
??? TQ2440# nand erase 0x100000 0x300000
??? NANDerase: device 0 offset 0x100000,size 0x300000
??? Erasingat 0x3e0000 -- 100% complete.
??? OK
??? TQ2440# nand write 0 0x100000 0x300000
??? NANDwrite: device 0 offset 0x100000,size 0x300000
??? 3145728 bytes written: OK
??? TQ2440# nand read 0x30004000 0x100000 0x300000
??? NANDread: device 0 offset 0x100000,size 0x300000
??? 3145728 bytes read: OK
??? TQ2440# md.b 0
??? 00000000:13 00 00 ea 14 f0 9f e5 14 f0 9f e5 14 f0 9f e5??????? ................
??? 00000010:14 f0 9f e5 14 f0 9f e5 14 f0 9f e5 14 f0 9f e5??????? ................
??? 00000020:e0 01 00 00 40 02 00 00 a0 02 00 00 00 03 00 00????????....@...........
??? 00000030:60 03 00 00 c0 03 00 00 20 04 00 00 ef be ad de????????....... .......
??? TQ2440# md.b 0x30004000
??? 30004000:13 00 00 ea 14 f0 9f e5 14 f0 9f e5 14 f0 9f e5????????................
??? 30004010:14 f0 9f e5 14 f0 9f e5 14 f0 9f e5 14 f0 9f e5????????................
??? 30004020:e0 01 00 00 40 02 00 00 a0 02 00 00 00 03 00 00????????....@...........
??? 30004030:60 03 00 00 c0 03 00 00 20 04 00 00 ef be ad de `??????....... .......
??? 上电之后显示 NAND FLASH 容量是256MB，说明检测到了 NAND FLASH ，然后将 SDRAM 中的内容写入 NAND FLASH，再从 NAND FLASH 中读出这些数据，通过比较可看出写入和读出的数据一致，因此判断对 NAND FLASH 的读写操作是正确的。
??? 如果打印出 NAND FLASH 更加详细的信息，可以修改 /home/huwei/uboot/u-boot-2011.06/drivers/mtd/nand/nand_base.c 的第2676行，把 MTDDEBUG 改成 printf ，并且去掉 MTD_DEBUG LEVEL0，编译烧写，重新上电后会有如下打印信息：
????U-Boot2011.06 (Aug 10 2011 - 23:55:48)
????DRAM: 64 MiB
????Flash: 2MiB
????NAND: NAND device: ManufacturerID: 0xec,Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit) ????256 MiB ????***Warning - bad CRC,using default environment ????In:? serial ????Out: serial ????Err: serial ????Net: CS8900-0 ????TQ2440 #
