一、硬件环境介绍
CPU:S3C2410(ARM920T)
RAM:64M SDRAM（HY57V561620(32MB)两片共64M，SDRAM 的起始地址为0x30000000）
Flash:64M NANDFLASH（K9F1208）
NOR FLASH:64K
网络芯片：CS8900A
串口1、2、3
USB主从接口
LCD液晶屏
二、软件环境介绍
VMware+fedora9
交叉编译器：arm-linux-gcc-3.4.1(soft-float)
U-Boot版本：u-boot-2009.08-rc2
skyeye模拟器：skyeye-1.2.8_rc1
三、移植要求
从Nand启动，支持tftp、nfs及usb，添加nand命令、写环境变量至nand和内核启动参数支持（bootcmd、bootargs），支持ping命令，能正常启动内核。
四、移植过程详解
1、准备
（1）安装skyeye并测试
修正bug：
【1】make install不成功
原因：缺少mkinstalldirs,下载一份，拷贝到thirdparty目录下，修改为可执行即可。
*(uint16_t *)value = (uint16_t)mem_read_halfword (offset);改为*value = (uint16_t)mem_read_halfword (offset);
重新编译安装即可。
另外还需要制作mknandflashdump程序（在device/nandflash/tools/下，执行gcc mknandflashdump.c生成a.out重命名为mknandflashdump,然后移动到/usr/local/bin目录下即可），以生成虚拟nandflash。
（2）安装交叉编译器
使用crosstool-4.3编译，一定要编译成softfloat的；
一个gcc版本过低的BUG：
patches/glibc-2.3.3-allow-gcc-4.0-configure.patch
- 3.[2-9]*)
+ 3.[2-9]*|4.[01]*)----------》3.[2-9]*|4.*)
2、阅读U-Boot的说明README，测试U-Boot
修改u-boot.lds，[.rodata:{*(.rodata)}];
make smdk2410_config
make成功
模拟测试：
编写skyeye.conf文件，生成nand.dump(mknandflashdump u-boot.bin nand.dump 0x0),然后执行
skyeye -c skyeye.conf即可。
skyeye.conf从skyeye测试包里拷贝一份，修改一下即可。
(从零地址开始的一块内存,file=./u-boot.bin,boot=yes)
3、修改U-boot代码，完成nand启动
(1)在start.S中添加搬运代码
/* boot from nand */
#ifdef CONFIG_S3C2410_NAND_BOOT
@ reset NAND
mov r1, #NAND_CTL_BASE
ldr r2, =0xf830 @ initial value
str r2, [r1, #oNFCONF]
ldr r2, [r1, #oNFCONF]
bic r2, r2, #0x800 @ enable chip
str r2, [r1, #oNFCONF]
mov r2, #0xff @ RESET command
strb r2, [r1, #oNFCMD]
mov r3, #0 @ wait
nand1:
add r3, r3, #0x1
cmp r3, #0xa
blt nand1
nand2:
ldr r2, [r1, #oNFSTAT] @ wait ready
tst r2, #0x1
beq nand2
ldr r2, [r1, #oNFCONF]
orr r2, r2, #0x800 @ disable chip
str r2, [r1, #oNFCONF]
@ get read to call C functions (for nand_read())
ldr sp, DW_STACK_START @ setup stack pointer
mov fp, #0 @ no previous frame, so fp=0
@ copy U-Boot to RAM
ldr r0, _TEXT_BASE
mov r1, #0x0
mov r2, #0x40000
bl nand_read_ll
tst r0, #0x0
beq ok_nand_read
bad_nand_read:
loop2: b loop2 @ infinite loop
ok_nand_read:
@ verify
mov r0, #0
ldr r1, _TEXT_BASE
mov r2, #0x400 @ 4 bytes * 1024 = 4K-bytes
go_next:
ldr r3, [r0], #4
ldr r4, [r1], #4
teq r3, r4
bne notmatch
subs r2, r2, #4
beq stack_setup
bne go_next
notmatch:
loop3: b loop3 @ infinite loop
#endif /* CONFIG_S3C2410_NAND_BOOT */
（2）在_start_armboot: .word start_armboot之后添加两行：
.align 2
DW_STACK_START: .word STACK_BASE+STACK_SIZE-4
（3）内存控制修改（lowlevel_init.S）
#define B1_BWSCON (DW16) @16位
（4）所需变量宏定义(include/configs/gyh2410.h)
#define oNFCONF 0x00
#define oNFCMD 0x04
#define oNFADDR 0x08
#define oNFDATA 0x0c
#define oNFSTAT 0x10
#define oNFECC 0x14
#define CONFIG_S3C2410_NAND_BOOT 1
#define STACK_BASE 0x33f00000
#define STACK_SIZE 0x8000
#define NAND_CTL_BASE 0x4E000000
（5）实现nand_read_ll函数（nand_read.c）
#define BUSY 1
inline void wait_idle(void) {
int i;
while(!(NFSTAT & BUSY))
for(i=0; i<10; i++);
}
/* low level nand read function */
int nand_read_ll(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
return -1; /* invalid alignment */
}
/* chip Enable */
NFCONF &= ~0x800;
for(i=0; i<10; i++);
for(i=start_addr; i < (start_addr + size);) {
/* READ0 */
NFCMD = 0;
/* Write Address */
NFADDR = i & 0xff;
NFADDR = (i >> 9) & 0xff;
NFADDR = (i >> 17) & 0xff;
NFADDR = (i >> 25) & 0xff;
wait_idle();
for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
*buf = (NFDATA & 0xff);
buf++;
}
}
/* chip Disable */
NFCONF |= 0x800; /* chip disable */
return 0;
}
编译、测试。
4、添加nand命令，写环境变量至nand
（1）配置命令支持
#define CONFIG_CMD_NAND
#define CONFIG_ENV_IS_IN_NAND 1
#define CONFIG_ENV_SIZE 0x10000 /* Total Size of Environment Sector */
#define CONFIG_ENV_OFFSET 0x40000
（2）实现board_nand_init函数（在nand_read.c中添加）
#include
#if 0
#define DEBUGN printf
#else
#define DEBUGN(x, args ...) {}
#endif
#include
#include
#include
#define __REGb(x) (*(volatile unsigned char *)(x))
#define __REGi(x) (*(volatile unsigned int *)(x))
#define NF_BASE 0x4e000000
#define NFCONF __REGi(NF_BASE + 0x0)
#define NFCMD __REGb(NF_BASE + 0x4)
#define NFADDR __REGb(NF_BASE + 0x8)
#define NFDATA __REGb(NF_BASE + 0xc)
#define NFSTAT __REGb(NF_BASE + 0x10)
#define NFECC0 __REGb(NF_BASE + 0x14)
#define NFECC1 __REGb(NF_BASE + 0x15)
#define NFECC2 __REGb(NF_BASE + 0x16)
#define S3C2410_NFCONF_EN (1<<15)
#define S3C2410_NFCONF_512BYTE (1<<14)
#define S3C2410_NFCONF_4STEP (1<<13)
#define S3C2410_NFCONF_INITECC (1<<12)
#define S3C2410_NFCONF_nFCE (1<<11)
#define S3C2410_NFCONF_TACLS(x) ((x)<<8)
#define S3C2410_NFCONF_TWRPH0(x) ((x)<<4)
#define S3C2410_NFCONF_TWRPH1(x) ((x)<<0)
#define S3C2410_ADDR_NALE 4
#define S3C2410_ADDR_NCLE 8
static void s3c2410_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
struct nand_chip *chip = mtd->priv;
DEBUGN("hwcontrol(): 0x%02x 0x%02x\n", cmd, ctrl);
if (ctrl & NAND_CTRL_CHANGE) {
ulong IO_ADDR_W = NF_BASE;
if (!(ctrl & NAND_CLE))
IO_ADDR_W |= S3C2410_ADDR_NCLE;
if (!(ctrl & NAND_ALE))
IO_ADDR_W |= S3C2410_ADDR_NALE;
chip->IO_ADDR_W = (void *)IO_ADDR_W;
if (ctrl & NAND_NCE)
NFCONF &= ~S3C2410_NFCONF_nFCE;
else
NFCONF |= S3C2410_NFCONF_nFCE;
}
if (cmd != NAND_CMD_NONE)
writeb(cmd, chip->IO_ADDR_W);
}
static int s3c2410_dev_ready(struct mtd_info *mtd)
{
DEBUGN("dev_ready\n");
return (NFSTAT & 0x01);
}
#ifdef CONFIG_S3C2410_NAND_HWECC
void s3c2410_nand_enable_hwecc(struct mtd_info *mtd, int mode)
{
DEBUGN("s3c2410_nand_enable_hwecc(%p, %d)\n", mtd, mode);
NFCONF |= S3C2410_NFCONF_INITECC;
}
static int s3c2410_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
u_char *ecc_code)
{
ecc_code[0] = NFECC0;
ecc_code[1] = NFECC1;
ecc_code[2] = NFECC2;
DEBUGN("s3c2410_nand_calculate_hwecc(%p,): 0x%02x 0x%02x 0x%02x\n",
mtd , ecc_code[0], ecc_code[1], ecc_code[2]);
return 0;
}
static int s3c2410_nand_correct_data(struct mtd_info *mtd, u_char *dat,
u_char *read_ecc, u_char *calc_ecc)
{
if (read_ecc[0] == calc_ecc[0] &&
read_ecc[1] == calc_ecc[1] &&
read_ecc[2] == calc_ecc[2])
return 0;
printf("s3c2410_nand_correct_data: not implemented\n");
return -1;
}
#endif
int board_nand_init(struct nand_chip *nand)
{
u_int32_t cfg;
u_int8_t tacls, twrph0, twrph1;
S3C24X0_CLOCK_POWER * const clk_power = S3C24X0_GetBase_CLOCK_POWER();
DEBUGN("board_nand_init()\n");
clk_power->CLKCON |= (1 << 4);
/* initialize hardware */
twrph0 = 3; twrph1 = 0; tacls = 0;
cfg = S3C2410_NFCONF_EN;
cfg |= S3C2410_NFCONF_TACLS(tacls - 1);
cfg |= S3C2410_NFCONF_TWRPH0(twrph0 - 1);
cfg |= S3C2410_NFCONF_TWRPH1(twrph1 - 1);
NFCONF = cfg;
/* initialize nand_chip data structure */
nand->IO_ADDR_R = nand->IO_ADDR_W = (void *)0x4e00000c;
/* read_buf and write_buf are default */
/* read_byte and write_byte are default */
/* hwcontrol always must be implemented */
nand->cmd_ctrl = s3c2410_hwcontrol;
nand->dev_ready = s3c2410_dev_ready;
#ifdef CONFIG_S3C2410_NAND_HWECC
nand->ecc.hwctl = s3c2410_nand_enable_hwecc;
nand->ecc.calculate = s3c2410_nand_calculate_ecc;
nand->ecc.correct = s3c2410_nand_correct_data;
nand->ecc.mode = NAND_ECC_HW3_512;
#else
nand->ecc.mode = NAND_ECC_SOFT;
#endif
#ifdef CONFIG_S3C2410_NAND_BBT
nand->options = NAND_USE_FLASH_BBT;
#else
nand->options = 0;
#endif
DEBUGN("end of nand_init\n");
return 0;
}
（2）配置nand
#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK 511
#define CONFIG_SYS_MAX_NAND_DEVICE 1
#define CONFIG_SYS_NAND_BASE 0x4E000000
5、支持tftp和nfs及usb，添加ping命令
#define CONFIG_CMD_NET
#define CONFIG_CMD_PING
#define CONFIG_USB_OHCI
#define CONFIG_USB_STORAGE
#define CONFIG_USB_KEYBOARD
#define CONFIG_DOS_PARTITION
#define CFG_DEVICE_DEREGISTER
#define CONFIG_SUPPORT_VFAT
#define LITTLEENDIAN
6、去除nor flash支持（板子上没有）
#define CONFIG_SYS_NO_FLASH
//#define PHYS_FLASH_1 0x00000000 /* Flash Bank #1 */
//#define CONFIG_SYS_FLASH_BASE PHYS_FLASH_1
//#define CONFIG_AMD_LV400 0 /* uncomment this if you have a LV400 flash */
#define CONFIG_SYS_MAX_FLASH_BANKS 0 /* max number of memory banks */
7、支持内核启动参数
#define CONFIG_BOOTDELAY 3
#define CONFIG_BOOTARGS "nointrd root=/dev/mtdblock2 console=ttySAC0,115200 mem=64M init=/linuxrc"
#define CONFIG_ETHADDR 08:00:3e:26:0a:5b
#define CONFIG_NETMASK 255.255.255.0
#define CONFIG_IPADDR 192.168.209.211
#define CONFIG_SERVERIP 192.168.209.129
#define CONFIG_BOOTCOMMAND "tftp 30008000 uImage; bootm 30008000"
8、skyeye模拟测试（skyeye -c skyeye.conf）
Your elf file is little endian.
arch: arm
cpu info: armv4, arm920t, 41009200, ff00fff0, 2
mach info: name s3c2410x, mach_init addr 0x806a9e0
ethmod num=1, mac addr=8:0:3e:26:a:5b, hostip=10.0.0.1
nandflash: dump ./nand.dump
file size:69206016
dbct info: turn on dbct!
uart_mod:0, desc_in:, desc_out:, converter:
SKYEYE: use arm920t mmu ops
Loaded RAM ./u-boot.bin
ERROR: s3c2410x_io_write_word(0x4c000000) = 0x00ffffff
ERROR: s3c2410x_io_write_word(0x4c000008) = 0x00048032
U-Boot 2009.08-rc2 ( 8月 31 2009 - 11:12:46)
DRAM: 64 MB
NAND: 64 MiB
Hit any key to stop autoboot: 0
GYH2410 #
9、注意事项
(1)命令定义时注意顺序，要在config_cmd_defaults.h引用之前或者添加到该头文件中
(2)去掉flash支持时Makefile中flash.o不能去掉，否则会引起错误，注意添加nand_read.o
10、存在的问题（望高手指点）
tftp和ping不正常的解决方法：修改net/tftp.c和net/nfs.c文件，将TIMEOUT改为10倍（因为是模拟，速度跟不上，所以要改）。
使用skyeye模拟时使用u-boot.bin可以，但是使用u-boot即会出现bus read error,且无法正常使用，经gdb调试发现nand_read_ll函数调用时参数传递不正确，难道时skyeye的原因？我换过1.2.6的版本还是不行。
