遇顺境，处之淡然；遇逆境，处之泰然
分类： LINUX
2012-03-10 19:55:24
u-boot-2010.06在mini2440上的移植（三）---增加nand flash功能
移植环境
1，主机环境：VMware7.1.4 + Ubuntu10.04
2，编译环境：arm-linux-gcc v4.3.2
3，开发板：mini2440，2M nor flash，256M nand flash，DM9000网卡。
4，u-boot版本：u-boot-2010.06
注：修改或添加的地方都用红色表示
移植步骤
(一)目前u-boot中还没有对2440上Nand Flash的支持，也就是说要想u-boot从Nand Flash上启动得自己去实现了。首先，在include/configs/mini2440.h头文件中定义Nand要用到的宏和寄存器，如下：
$ gedit include/configs/mini2440.h
#define CONFIG_CMD_NAND
//在文件末尾加入以下Nand Flash相关定义
//#define CONFIG_ENV_IS_IN_FLASH 1 /*屏蔽Nor Flash saveenv相关宏定义*/
//#define CONFIG_ENV_SIZE 0x10000 /* Total Size of Environment Sector */
#define CONFIG_ENV_IS_IN_NAND 1
#define CONFIG_ENV_OFFSET 0x60000
#define CONFIG_ENV_SIZE 0x20000
#define CONFIG_CMD_SAVEENV
/*
* Nand flash register and envionment variables
*/
#define CONFIG_S3C2440_NAND_BOOT 1
#define NAND_CTL_BASE 0x4E000000 //Nand Flash配置寄存器基地址，查2440手册可得知
#define bINT_CTL(Nb) __REG(INT_CTL_BASE+(Nb))
#define UBOOT_RAM_BASE 0x33f80000
#define STACK_BASE 0x33F00000 //定义堆栈的地址
#define STACK_SIZE 0x8000 //堆栈的长度大小
/* NAND flash settings */
#if defined(CONFIG_CMD_NAND)
#define CONFIG_NAND_S3C2410
#define CONFIG_SYS_NAND_BASE 0x4E000000 //Nand配置寄存器基地址
#define CONFIG_SYS_MAX_NAND_DEVICE 1
#define NAND_MAX_CHIPS 1
#define CONFIG_MTD_NAND_VERIFY_WRITE 1
//#define NAND_SAMSUNG_LP_OPTIONS 1 //注意:我们这里是64M的Nand Flash,所以不用,如果是128M的大块Nand Flash,则需加上
#endif
(二)其次，修改cpu/arm920t/start.S这个文件，使u-boot从Nand Flash启动，在上一节中提过，u-boot默认是从Nor Flash启动的。修改部分如下：
$ gedit arch/arm/cpu/arm920t/start.S
/*注意：在上一篇Nor Flash启动中，我们为了把u-boot用supervivi下载到内存中运行而屏蔽掉这段有关CPU初始化的代码。而现在我们要把u-boot下载到Nand Flash中，从Nand Flash启动，所以现在要恢复这段代码。*/
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
bl cpu_init_crit
#endif
#if 0 //屏蔽掉u-boot中的从Nor Flash启动部分
#ifndef CONFIG_SKIP_RELOCATE_UBOOT
relocate: /* relocate U-Boot to RAM */
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
ldr r2, _armboot_start
ldr r3, _bss_start
sub r2, r3, r2 /* r2 <- size of armboot */
add r2, r0, r2 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
#endif
/***************** CHECK_CODE_POSITION ******************************************/
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
/***************** CHECK_CODE_POSITION ******************************************/
/***************** CHECK_BOOT_FLASH ******************************************/
ldr r1, =( (4<<28)|(3<<4)|(3<<2) ) /* address of Internal SRAM 0x4000003C*/
mov r0, #0 /* r0 = 0 */
str r0, [r1]
mov r1, #0x3c /* address of men 0x0000003C*/
ldr r0, [r1]
cmp r0, #0
bne relocate
/* recovery */
ldr r0, =(0xdeadbeef)
ldr r1, =( (4<<28)|(3<<4)|(3<<2) )
str r0, [r1]
/***************** CHECK_BOOT_FLASH ******************************************/
/***************** NAND_BOOT *************************************************/
//下面添加2440中u-boot从Nand Flash启动
#ifdef CONFIG_S3C2440_NAND_BOOT
#define oNFCONF 0x00
#define oNFCONT 0x04
#define oNFCMD 0x08
#define oNFSTAT 0x20
#define LENGTH_UBOOT 0x60000
mov r1, #NAND_CTL_BASE //复位Nand Flash
ldr r2, =( (7<<12)|(7<<8)|(7<<4)|(0<<0) )
str r2, [r1, #oNFCONF] //设置配置寄存器的初始值，参考s3c2440手册
ldr r2, [r1, #oNFCONF]
ldr r2, =( (1<<4)|(0<<1)|(1<<0) )
str r2, [r1, #oNFCONT] //设置控制寄存器
ldr r2, [r1, #oNFCONT]
ldr r2, =(0x6) //RnB Clear
str r2, [r1, #oNFSTAT]
ldr r2, [r1, #oNFSTAT]
mov r2, #0xff //复位command
strb r2, [r1, #oNFCMD]
mov r3, #0 //等待
nand1:
add r3, r3, #0x1
cmp r3, #0xa
blt nand1
nand2:
ldr r2, [r1, #oNFSTAT] //等待就绪
tst r2, #0x4
beq nand2
ldr r2, [r1, #oNFCONT]
orr r2, r2, #0x2 //取消片选
str r2, [r1, #oNFCONT]
//get read to call C functions (for nand_read())
ldr sp, DW_STACK_START //为C代码准备堆栈,DW_STACK_START定义在下面
mov fp, #0
//copy U-Boot to RAM
ldr r0, =TEXT_BASE//传递给C代码的第一个参数：u-boot在RAM中的起始地址
mov r1, #0x0 //传递给C代码的第二个参数：Nand Flash的起始地址
mov r2, # LENGTH_UBOOT //传递给C代码的第三个参数：u-boot的长度大小(128k)
bl nand_read_ll //此处调用C代码中读Nand的函数，现在还没有要自己编写实现
tst r0, #0x0
beq ok_nand_read
bad_nand_read:
loop2: b loop2 //infinite loop
ok_nand_read: //检查搬移后的数据，如果前4k完全相同，表示搬移成功
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_S3C2440_NAND_BOOT
/***************** NAND_BOOT *************************************************/
/***************** NOR_BOOT *************************************************/
relocate: /* relocate U-Boot to RAM */
/*********** CHECK_FOR_MAGIC_NUMBER***************/
ldr r1, =(0xdeadbeef)
cmp r0, r1
bne loop3
/*********** CHECK_FOR_MAGIC_NUMBER***************/
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
ldr r2, _armboot_start
ldr r3, _bss_start
sub r2, r3, r2 /* r2 <- size of armboot */
add r2, r0, r2 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
stmia r1!, {r3-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end addreee [r2] */
ble copy_loop
/***************** NOR_BOOT *************************************************/
/* Set up the stack */
stack_setup:
ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
sub r0, r0, #CONFIG_SYS_MALLOC_LEN /* malloc area */
sub r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /* bdinfo */
#ifdef CONFIG_USE_IRQ
sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
#endif
sub sp, r0, #12 /* leave 3 words for abort-stack */
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
clear_bss:
ldr r0, _bss_start /* find start of bss segment */
ldr r1, _bss_end /* stop here */
mov r2, #0x00000000 /* clear */
clbss_l:str r2, [r0] /* clear loop... */
add r0, r0, #4
cmp r0, r1
ble clbss_l
ldr pc, _start_armboot
#if defined(CONFIG_S3C2440) //区别与其他开发板
//根据mini2440原理图可知LED分别由S3C2440的PB5、6、7、8口来控制，以下是PB端口寄存
//器基地址(查2440的DataSheet得知)
#define GPBCON 0x56000010
#define GPBDAT 0x56000014
#define GPBUP 0x56000018
//以下对寄存器的操作参照S3C2440的DataSheet进行操作
ldr r0, =GPBUP
ldr r1, =0x7FF //即：二进制11111111111，关闭PB口上拉
str r1, [r0]
ldr r0, =GPBCON //配置PB5、6、7、8为输出口，对应PBCON寄存器的第10-17位
ldr r1, =0x154FD //即：二进制010101010011111101
str r1, [r0]
ldr r0, =GPBDAT
ldr r1, =0x1C0 //即：二进制111000000，PB5设为低电平，6、7、8为高电平
str r1, [r0]
#endif
//此段代码使u-boot启动后，点亮开发板上的LED1，LED2、LED3、LED4不亮
_start_armboot: .word start_armboot //在这一句的下面加上DW_STACK_START的定义
.align 2
DW_STACK_START: .word STACK_BASE+STACK_SIZE-4
(三)再次，在board/samsung/mini2440/目录下新建一个nand_read.c文件，在该文件中来实现上面汇编中要调用的nand_read_ll函数，代码如下：
$ gedit board/jason/mini2440/nand_read.c //新建一个nand_read.c文件，记得保存
#include
#include
#define __REGb(x) (*(volatile unsigned char *)(x))
#define __REGw(x) (*(volatile unsigned short *)(x))
#define __REGi(x) (*(volatile unsigned int *)(x))
#define NF_BASE 0x4e000000
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
#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 NFSTAT_BUSY 1
#define nand_select() (NFCONF &= ~0x800)
#define nand_deselect() (NFCONF |= 0x800)
#define nand_clear_RnB() do {} while (0)
#elif defined(CONFIG_S3C2440) || defined(CONFIG_S3C2442)
#define NFCONF __REGi(NF_BASE + 0x0)
#define NFCONT __REGi(NF_BASE + 0x4)
#define NFCMD __REGb(NF_BASE + 0x8)
#define NFADDR __REGb(NF_BASE + 0xc)
#define NFDATA __REGb(NF_BASE + 0x10)
#define NFDATA16 __REGw(NF_BASE + 0x10)
#define NFSTAT __REGb(NF_BASE + 0x20)
#define NFSTAT_BUSY 1
#define nand_select() (NFCONT &= ~(1 << 1))
#define nand_deselect() (NFCONT |= (1 << 1))
#define nand_clear_RnB() (NFSTAT |= (1 << 2))
#endif
static inline void nand_wait(void)
{
int i;
while (!(NFSTAT & NFSTAT_BUSY))
for (i=0; i<10; i++);
}
struct boot_nand_t {
int page_size;
int block_size;
int bad_block_offset;
// unsigned long size;
};
static int is_bad_block(struct boot_nand_t * nand, unsigned long i)
{
unsigned char data;
unsigned long page_num;
nand_clear_RnB();
if (nand->page_size == 512) {
NFCMD = NAND_CMD_READOOB; /* 0x50 */
NFADDR = nand->bad_block_offset & 0xf;
NFADDR = (i >> 9) & 0xff;
NFADDR = (i >> 17) & 0xff;
NFADDR = (i >> 25) & 0xff;
} else if (nand->page_size == 2048) {
page_num = i >> 11; /* addr / 2048 */
NFCMD = NAND_CMD_READ0;
NFADDR = nand->bad_block_offset & 0xff;
NFADDR = (nand->bad_block_offset >> 8) & 0xff;
NFADDR = page_num & 0xff;
NFADDR = (page_num >> 8) & 0xff;
NFADDR = (page_num >> 16) & 0xff;
NFCMD = NAND_CMD_READSTART;
} else {
return -1;
}
nand_wait();
data = (NFDATA & 0xff);
if (data != 0xff)
return 1;
return 0;
}
static int nand_read_page_ll(struct boot_nand_t * nand, unsigned char *buf, unsigned long addr)
{
unsigned short *ptr16 = (unsigned short *)buf;
unsigned int i, page_num;
nand_clear_RnB();
NFCMD = NAND_CMD_READ0;
if (nand->page_size == 512) {
/* Write Address */
NFADDR = addr & 0xff;
NFADDR = (addr >> 9) & 0xff;
NFADDR = (addr >> 17) & 0xff;
NFADDR = (addr >> 25) & 0xff;
} else if (nand->page_size == 2048) {
page_num = addr >> 11; /* addr / 2048 */
/* Write Address */
NFADDR = 0;
NFADDR = 0;
NFADDR = page_num & 0xff;
NFADDR = (page_num >> 8) & 0xff;
NFADDR = (page_num >> 16) & 0xff;
NFCMD = NAND_CMD_READSTART;
} else {
return -1;
}
nand_wait();
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
for (i = 0; i < nand->page_size; i++) {
*buf = (NFDATA & 0xff);
buf++;
}
#elif defined(CONFIG_S3C2440) || defined(CONFIG_S3C2442)
for (i = 0; i < (nand->page_size>>1); i++) {
*ptr16 = NFDATA16;
ptr16++;
}
#endif
return nand->page_size;
}
static unsigned short nand_read_id()
{
unsigned short res = 0;
NFCMD = NAND_CMD_READID;
NFADDR = 0;
res = NFDATA;
res = (res << 8) | NFDATA;
return res;
}
extern unsigned int dynpart_size[];
/* low level nand read function */
int nand_read_ll(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
unsigned short nand_id;
struct boot_nand_t nand;
/* chip Enable */
nand_select();
nand_clear_RnB();
for (i = 0; i < 10; i++)
;
nand_id = nand_read_id();
if (0) { /* dirty little hack to detect if nand id is misread */
unsigned short * nid = (unsigned short *)0x31fffff0;
*nid = nand_id;
}
if (nand_id == 0xec76 || /* Samsung K91208 */
nand_id == 0xad76 ) { /*Hynix HY27US08121A*/
nand.page_size = 512;
nand.block_size = 16 * 1024;
nand.bad_block_offset = 5;
// nand.size = 0x4000000;
} else if (nand_id == 0xecf1 || /* Samsung K9F1G08U0B */
nand_id == 0xecda || /* Samsung K9F2G08U0B */
nand_id == 0xecd3 ) { /* Samsung K9K8G08 */
nand.page_size = 2048;
nand.block_size = 128 * 1024;
nand.bad_block_offset = nand.page_size;
// nand.size = 0x8000000;
} else {
return -1; // hang
}
if ((start_addr & (nand.block_size-1)) || (size & ((nand.block_size-1))))
return -1; /* invalid alignment */
for (i=start_addr; i < (start_addr + size);) {
#ifdef CONFIG_S3C2410_NAND_SKIP_BAD
if (i & (nand.block_size-1)== 0) {
if (is_bad_block(&nand, i) ||
is_bad_block(&nand, i + nand.page_size)) {
/* Bad block */
i += nand.block_size;
size += nand.block_size;
continue;
}
}
#endif
j = nand_read_page_ll(&nand, buf, i);
i += j;
buf += j;
}
/* chip Disable */
nand_deselect();
return 0;
}
(四)然后，在board/samsung/mini2440/Makefile中添加nand_read.c的编译选项，使他编译到u-boot中，如下：
COBJS := mini2440.o flash.o nand_read.o
(五)在上一节中我们说过，通常在嵌入式bootloader中，有两种方式来引导启动内核：从Nor Flash启动和从Nand Flash启动，但不管是从Nor启动或者从Nand启动，进入第二阶段以后，两者的执行流程是相同的。
现在的u-boot-2010-06版本对Nand的初始化、读写实现是基于最近的Linux内核的MTD架构，删除了以前传统的执行方法，使移植没有以前那样复杂了，实现Nand的操作和基本命令都直接在drivers/mtd/nand目录下(在doc/README.nand中讲得很清楚)。下面我们结合代码来分析一下u-boot在第二阶段的执行流程：
|
1.lib_arm/board.c文件中的start_armboot函数调用了drivers/mtd/nand/nand.c文件中的nand_init函数，如下： #if defined(CONFIG_CMD_NAND) //可以看到CONFIG_CMD_NAND宏决定了Nand的初始化 puts ("NAND: "); nand_init(); #endif 2.nand_init调用了同文件下的nand_init_chip函数； 3.nand_init_chip函数调用drivers/mtd/nand/s3c2410_nand.c文件下的board_nand_init函数，然后再调用drivers/mtd/nand/nand_base.c函数中的nand_scan函数； 4.nand_scan函数调用了同文件下的nand_scan_ident函数等。 |
我们在u-boot提供的关于S3C2410的nand_flash驱动文件的基础上添加相关代码以支持S3C2440.
$ gedit drivers/mtd/nand/s3c2410_nand.c
#include
#include
#include
#include
#define NF_BASE 0x4e000000
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
#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
#endif
#if defined(CONFIG_S3C2440)
#define S3C2410_NFCONT_EN (1<<0)
#define S3C2410_NFCONT_INITECC (1<<4)
#define S3C2410_NFCONT_nFCE (1<<1)
#define S3C2410_NFCONT_MAINECCLOCK (1<<5)
#define S3C2410_NFCONF_TACLS(x) ((x)<<12)
#define S3C2410_NFCONF_TWRPH0(x) ((x)<<8)
#define S3C2410_NFCONF_TWRPH1(x) ((x)<<4)
#define S3C2410_ADDR_NALE 0x08
#define S3C2410_ADDR_NCLE 0x0c
#endif
ulong IO_ADDR_W = NF_BASE;
#ifdef CONFIG_NAND_SPL
/* in the early stage of NAND flash booting, printf() is not available */
#define printf(fmt, args...)
static void nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
int i;
struct nand_chip *this = mtd->priv;
for (i = 0; i < len; i++)
buf[i] = readb(this->IO_ADDR_R);
}
#endif
static void s3c2410_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
// struct nand_chip *chip = mtd->priv;
struct s3c2410_nand *nand = s3c2410_get_base_nand();
debugX(1, "hwcontrol(): 0x%02x 0x%02x/n", cmd, ctrl);
if (ctrl & NAND_CTRL_CHANGE) {
// ulong IO_ADDR_W = (ulong) nand;
IO_ADDR_W = (ulong)nand;
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 defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
if (ctrl & NAND_NCE)
writel(readl(&nand->NFCONF) & ~S3C2410_NFCONF_nFCE,
&nand->NFCONF);
else
writel(readl(&nand->NFCONF) | S3C2410_NFCONF_nFCE,
&nand->NFCONF);
}
#endif
#if defined(CONFIG_S3C2440)
if (ctrl & NAND_NCE)
writel(readl(&nand->NFCONT) & ~S3C2410_NFCONT_nFCE,
&nand->NFCONT);
else
writel(readl(&nand->NFCONT) | S3C2410_NFCONT_nFCE,
&nand->NFCONT);
}
#endif
if (cmd != NAND_CMD_NONE)
// writeb(cmd, chip->IO_ADDR_W);
writeb(cmd, (void *)IO_ADDR_W);
}
static int s3c2410_dev_ready(struct mtd_info *mtd)
{
struct s3c2410_nand *nand = s3c2410_get_base_nand();
debugX(1, "dev_ready/n");
return readl(&nand->NFSTAT) & 0x01;
}
#ifdef CONFIG_S3C2410_NAND_HWECC
void s3c2410_nand_enable_hwecc(struct mtd_info *mtd, int mode)
{
struct s3c2410_nand *nand = s3c2410_get_base_nand();
debugX(1, "s3c2410_nand_enable_hwecc(%p, %d)/n", mtd, mode);
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
writel(readl(&nand->NFCONF) | S3C2410_NFCONF_INITECC, &nand->NFCONF);
#endif
#if defined(CONFIG_S3C2440)
writel(readl(&nand->NFCONT) | S3C2410_NFCONT_INITECC, &nand->NFCONT);
#endif
}
static int s3c2410_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
u_char *ecc_code)
{
struct s3c2410_nand *nand = s3c2410_get_base_nand();
ecc_code[0] = readb(&nand->NFECC);
ecc_code[1] = readb(&nand->NFECC + 1);
ecc_code[2] = readb(&nand->NFECC + 2);
debugX(1, "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;
struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
struct s3c2410_nand *nand_reg = s3c2410_get_base_nand();
debugX(1, "board_nand_init()/n");
writel(readl(&clk_power->CLKCON) | (1 << 4), &clk_power->CLKCON);
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
/* 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);
writel(cfg, &nand_reg->NFCONF);
/* initialize nand_chip data structure */
nand->IO_ADDR_R = nand->IO_ADDR_W = (void *)&nand_reg->NFDATA;
#endif
#if defined(CONFIG_S3C2440)
twrph0 = 4;
twrph1 = 2;
tacls = 0;
cfg = 0;
cfg |= S3C2410_NFCONF_TACLS(tacls - 1);
cfg |= S3C2410_NFCONF_TWRPH0(twrph0 - 1);
cfg |= S3C2410_NFCONF_TWRPH1(twrph1 - 1);
writel(cfg, &nand_reg->NFCONF);
cfg = (0<<13)|(0<<12)|(0<<10)|(0<<9)|(0<<8)|(0<<6)|(0<<5)|(1<<4)|(0<<1)|(1<<0);
writel(cfg, &nand_reg->NFCONT);
/* initialize nand_chip data structure */
nand->IO_ADDR_R = nand->IO_ADDR_W = (void *)&nand_reg->NFDATA;
#endif
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 = 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_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_S3C2410_NAND_BBT
nand->options = NAND_USE_FLASH_BBT;
#else
nand->options = 0;
#endif
debugX(1, "end of nand_init/n");
return 0;
}
(六) 修改s3c24x0.h，增加Nand flash寄存器定义
$ gedit arch/arm/include/asm/arch-s3c24x0/s3c24x0.h
#if defined(CONFIG_S3C2440)
struct s3c2410_nand {
u32 NFCONF;
u32 NFCONT;
u32 NFCMD;
u32 NFADDR;
u32 NFDATA;
u32 NFMECCD0;
u32 NFMECCD1;
u32 NFSECCD;
u32 NFSTAT;
u32 NFESTAT0;
u32 NFESTAT1;
u32 NFMECC0;
u32 NFMECC1;
u32 NFSECC;
u32 NFSBLK;
u32 NFEBLK;
};
#endif
#if defined(CONFIG_S3C2410)&& !defined (CONFIG_S3C2440)
/* NAND FLASH (see S3C2410 manual chapter 6) */
struct s3c2410_nand {
u32 NFCONF;
u32 NFCMD;
u32 NFADDR;
u32 NFDATA;
u32 NFSTAT;
u32 NFECC;
};
#endif
(七)还有一个重要的地方要修改，在cpu/arm920t/u-boot.lds中，这个u-boot启动连接脚本文件决定了u-boot运行的入口地址，以及各个段的存储位置，这也是链接定位的作用。添加下面两行代码的主要目的是防止编译器把我们自己添加的用于nandboot的子函数放到4K之后，否则是无法启动的。如下：
$ gedit arch/arm/cpu/arm920t/u-boot.lds
.text :
{
arch/arm/cpu/arm920t/start.o (.text)
board/jason/mini2440/lowlevel_init.o (.text)
board/jason/mini2440/nand_read.o (.text)
*(.text)
}
(八)编译成功后生成u-boot.bin文件。下载时先将mini2440开发板调到Nor启动档，利用supervivi的a命令将u-boot.bin下载到开发板的Nand Flash中，再把开发板调到Nand启动档，打开电源就从Nand Flash启动了，启动结果如下：
可以看到环境变量保存成功，将开发板重启后不会再有bad CRC警告，nand flash 移植成功。
