Uboot在S3C2440上的移植詳解（三）

#gedit include/configs/my2440.h //在文件末尾加入以下Nand Flash相關(guān)定義

/*
* 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手冊可得知

#define STACK_BASE 0x33F00000 //定義堆棧的地址
#define STACK_SIZE 0x8000 //堆棧的長度大小

#define oNFCONF 0x00 //相對Nand配置寄存器基地址的偏移量，還是配置寄存器的基地址
#define oNFCONT 0x04 //相對Nand配置寄存器基地址的偏移量，可得到控制寄存器的基地址(0x4E000004)

#define oNFADDR 0x0c //相對Nand配置寄存器基地址的偏移量，可得到地址寄存器的基地址(0x4E00000c)
#define oNFDATA 0x10 //相對Nand配置寄存器基地址的偏移量，可得到數(shù)據(jù)寄存器的基地址(0x4E000010)
#define oNFCMD 0x08 //相對Nand配置寄存器基地址的偏移量，可得到指令寄存器的基地址(0x4E000008)
#define oNFSTAT 0x20 //相對Nand配置寄存器基地址的偏移量，可得到狀態(tài)寄存器的基地址(0x4E000020)

#define oNFECC 0x2c //相對Nand配置寄存器基地址的偏移量，可得到ECC寄存器的基地址(0x4E00002c)

#gedit cpu/arm920t/start.S

//注意：在上一篇Nor Flash啟動中，我們?yōu)榱税製-boot用supervivi下載到內(nèi)存中運(yùn)行而屏蔽掉這段有關(guān)CPU初始化的代碼。而現(xiàn)在我們要把u-boot下載到Nand Flash中，從Nand Flash啟動，所以現(xiàn)在要恢復(fù)這段代碼。

#ifndef CONFIG_SKIP_LOWLEVEL_INIT
bl cpu_init_crit
#endif

#if 0//屏蔽掉u-boot中的從Nor Flash啟動部分
#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 /* dont 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

//下面添加2440中u-boot從Nand Flash啟動

#ifdef CONFIG_S3C2440_NAND_BOOT
mov r1, #NAND_CTL_BASE //復(fù)位Nand Flash
ldr r2, =( (7<<12)|(7<<8)|(7<<4)|(0<<0) )
str r2, [r1, #oNFCONF] //設(shè)置配置寄存器的初始值，參考s3c2440手冊
ldr r2, [r1, #oNFCONF]

ldr r2, =( (1<<4)|(0<<1)|(1<<0) )
str r2, [r1, #oNFCONT] //設(shè)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 //復(fù)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] //等待就緒
tst r2, #0x4
beq nand2

ldr r2, [r1, #oNFCONT]
orr r2, r2, #0x2 //取消片選
str r2, [r1, #oNFCONT]

//get read to call C functions (for nand_read())
ldr sp, DW_STACK_START //為C代碼準(zhǔn)備堆棧,DW_STACK_START定義在下面
mov fp, #0

//copy U-Boot to RAM
ldr r0, =TEXT_BASE//傳遞給C代碼的第一個(gè)參數(shù)：u-boot在RAM中的起始地址
mov r1, #0x0 //傳遞給C代碼的第二個(gè)參數(shù)：Nand Flash的起始地址
mov r2, #0x30000 //傳遞給C代碼的第三個(gè)參數(shù)：u-boot的長度大小(128k)
bl nand_read_ll //此處調(diào)用C代碼中讀Nand的函數(shù)，現(xiàn)在還沒有要自己編寫實(shí)現(xiàn)
tst r0, #0x0
beq ok_nand_read

bad_nand_read:
loop2: b loop2 //infinite loop

ok_nand_read:
//檢查搬移后的數(shù)據(jù)，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

_start_armboot: .word start_armboot //在這一句的下面加上DW_STACK_START的定義

.align 2
DW_STACK_START: .word STACK_BASE+STACK_SIZE-4

COBJS := my2440.o flash.o nand_read.o

.text :
{
cpu/arm920t/start.o (.text)
board/samsung/my2440/lowlevel_init.o (.text)
board/samsung/my2440/nand_read.o (.text)
*(.text)
}

#gedit include/configs/my2440.h

//注釋掉環(huán)境變量保存到Flash的宏(注意：如果你要使用上一篇中的從Nor啟動的saveenv命令，則要恢復(fù)這些Flash宏定義)

//#define CONFIG_ENV_IS_IN_FLASH 1
//#define CONFIG_ENV_SIZE 0x10000 /* Total Size of Environment Sector */

//添加環(huán)境變量保存到Nand的宏(注意：如果你要使用上一篇中的從Nor啟動的saveenv命令，則不要這些Nand宏定義)

#define CONFIG_ENV_IS_IN_NAND 1
#define CONFIG_ENV_OFFSET 0x30000 //將環(huán)境變量保存到nand中的0x30000位置
#define CONFIG_ENV_SIZE 0x10000 /* Total Size of Environment Sector */

#gedit drivers/mtd/nand/s3c2440_nand.c //新建s3c2440_nand.c文件

#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 //Nand配置寄存器基地址
#define NFCONF __REGi(NF_BASE + 0x0) //偏移后還是得到配置寄存器基地址
#define NFCONT __REGi(NF_BASE + 0x4) //偏移后得到Nand控制寄存器基地址
#define NFCMD __REGb(NF_BASE + 0x8) //偏移后得到Nand指令寄存器基地址
#define NFADDR __REGb(NF_BASE + 0xc) //偏移后得到Nand地址寄存器基地址
#define NFDATA __REGb(NF_BASE + 0x10) //偏移后得到Nand數(shù)據(jù)寄存器基地址
#define NFMECCD0 __REGi(NF_BASE + 0x14) //偏移后得到Nand主數(shù)據(jù)區(qū)域ECC0寄存器基地址
#define NFMECCD1 __REGi(NF_BASE + 0x18) //偏移后得到Nand主數(shù)據(jù)區(qū)域ECC1寄存器基地址
#define NFSECCD __REGi(NF_BASE + 0x1C) //偏移后得到Nand空閑區(qū)域ECC寄存器基地址
#define NFSTAT __REGb(NF_BASE + 0x20) //偏移后得到Nand狀態(tài)寄存器基地址
#define NFSTAT0 __REGi(NF_BASE + 0x24) //偏移后得到Nand ECC0狀態(tài)寄存器基地址
#define NFSTAT1 __REGi(NF_BASE + 0x28) //偏移后得到Nand ECC1狀態(tài)寄存器基地址
#define NFMECC0 __REGi(NF_BASE + 0x2C) //偏移后得到Nand主數(shù)據(jù)區(qū)域ECC0狀態(tài)寄存器基地址
#define NFMECC1 __REGi(NF_BASE + 0x30) //偏移后得到Nand主數(shù)據(jù)區(qū)域ECC1狀態(tài)寄存器基地址
#define NFSECC __REGi(NF_BASE + 0x34) //偏移后得到Nand空閑區(qū)域ECC狀態(tài)寄存器基地址
#define NFSBLK __REGi(NF_BASE + 0x38) //偏移后得到Nand塊開始地址
#define NFEBLK __REGi(NF_BASE + 0x3c) //偏移后得到Nand塊結(jié)束地址

#define S3C2440_NFCONT_nCE (1<<1)
#define S3C2440_ADDR_NALE 0x0c
#define S3C2440_ADDR_NCLE 0x08

ulong IO_ADDR_W = NF_BASE;

static void s3c2440_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
struct nand_chip *chip = mtd->priv;

DEBUGN("hwcontrol(): 0x%02x 0x%02xn", cmd, ctrl);

if (ctrl & NAND_CTRL_CHANGE) {
IO_ADDR_W = NF_BASE;

if (!(ctrl & NAND_CLE)) //要寫的是地址
IO_ADDR_W |= S3C2440_ADDR_NALE;
if (!(ctrl & NAND_ALE)) //要寫的是命令
IO_ADDR_W |= S3C2440_ADDR_NCLE;

if (ctrl & NAND_NCE)
NFCONT &= ~S3C2440_NFCONT_nCE; //使能nand flash
else
NFCONT |= S3C2440_NFCONT_nCE; //禁止nand flash
}

if (cmd != NAND_CMD_NONE)
writeb(cmd,(void *)IO_ADDR_W);
}

static int s3c2440_dev_ready(struct mtd_info *mtd)
{
DEBUGN("dev_readyn");
return (NFSTAT & 0x01);
}

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);

twrph0 = 4; twrph1 = 2; tacls = 0;

cfg = (tacls<<12)|(twrph0<<8)|(twrph1<<4);
NFCONF = cfg;

cfg = (1<<6)|(1<<4)|(0<<1)|(1<<0);
NFCONT = cfg;

/* initialize nand_chip data structure */
nand->IO_ADDR_R = nand->IO_ADDR_W = (void *)0x4e000010;

/* read_buf and write_buf are default */
/* read_byte and write_byte are default */

/* hwcontrol always must be implemented */
nand->cmd_ctrl = s3c2440_hwcontrol;

nand->dev_ready = s3c2440_dev_ready;

return 0;
}

#gedit include/configs/my2440.h

/* Command line configuration. */
#define CONFIG_CMD_NAND
#define CONFIG_CMDLINE_EDITING

#ifdef CONFIG_CMDLINE_EDITING
#undef CONFIG_AUTO_COMPLETE
#else
#define CONFIG_AUTO_COMPLETE
#endif

/* NAND flash settings */
#if defined(CONFIG_CMD_NAND)
#define CONFIG_SYS_NAND_BASE 0x4E000000 //Nand配置寄存器基地址
#define CONFIG_SYS_MAX_NAND_DEVICE 1
#define CONFIG_MTD_NAND_VERIFY_WRITE 1
//#define NAND_SAMSUNG_LP_OPTIONS 1 //注意：我們這里是64M的Nand Flash，所以不用，如果是128M的大塊Nand Flash，則需加上
#endif

# gedit drivers/mtd/nand/Makefile

COBJS-y += s3c2440_nand.o
COBJS-$(CONFIG_NAND_S3C2440)+= s3c2440_nand.o

1.lib_arm/board.c文件中的start_armboot函數(shù)調(diào)用了drivers/mtd/nand/nand.c文件中的nand_init函數(shù)，如下：
#if defined(CONFIG_CMD_NAND) //可以看到CONFIG_CMD_NAND宏決定了Nand的初始化
puts ("NAND: ");
nand_init();
#endif

2.nand_init調(diào)用了同文件下的nand_init_chip函數(shù)；
3.nand_init_chip函數(shù)調(diào)用drivers/mtd/nand/s3c2410_nand.c文件下的board_nand_init函數(shù)，然后再調(diào)用drivers/mtd/nand/nand_base.c函數(shù)中的nand_scan函數(shù)；
4.nand_scan函數(shù)調(diào)用了同文件下的nand_scan_ident函數(shù)等。

#gedit board/samsung/my2440/nand_read.c //新建一個(gè)nand_read.c文件，記得保存

#include

#define NF_BASE 0x4E000000 //Nand Flash配置寄存器基地址

#define __REGb(x)(*(volatile unsigned char *)(x))
#define __REGi(x)(*(volatile unsigned int*)(x))

#define NFCONF __REGi(NF_BASE + 0x0 ) //通過偏移量還是得到配置寄存器基地址
#define NFCONT __REGi(NF_BASE + 0x4 ) //通過偏移量得到控制寄存器基地址
#define NFCMD __REGb(NF_BASE + 0x8 ) //通過偏移量得到指令寄存器基地址
#define NFADDR __REGb(NF_BASE + 0xC ) //通過偏移量得到地址寄存器基地址
#define NFDATA __REGb(NF_BASE + 0x10) //通過偏移量得到數(shù)據(jù)寄存器基地址
#define NFSTAT __REGb(NF_BASE + 0x20) //通過偏移量得到狀態(tài)寄存器基地址

#define NAND_CHIP_ENABLE (NFCONT &= ~(1<<1)) //Nand片選使能
#define NAND_CHIP_DISABLE (NFCONT |= (1<<1)) //取消Nand片選
#define NAND_CLEAR_RB (NFSTAT |= (1<<2))
#define NAND_DETECT_RB { while(! (NFSTAT&(1<<2)) );}

#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)

/*low level nand read function */
int nand_read_ll(unsigned char *buf, unsigned long start_addr,intsize)
{
int i, j;

if((start_addr & NAND_BLOCK_MASK)||(size & NAND_BLOCK_MASK))
{
return -1;//地址或長度不對齊
}

NAND_CHIP_ENABLE; //選中Nand片選

for(i=start_addr; i <(start_addr +size);)
{
//發(fā)出READ0指令

NAND_CLEAR_RB;
NFCMD = 0;

//對Nand進(jìn)行尋址
NFADDR = i & 0xFF;

NFADDR =(i >> 9) & 0xFF;
NFADDR =(i >> 17) & 0xFF;
NFADDR =(i >> 25) & 0xFF;

NAND_DETECT_RB;

for(j=0; j < NAND_SECTOR_SIZE; j++, i++)
{
*buf =(NFDATA & 0xFF);
buf++;
}
}

NAND_CHIP_DISABLE; //取消片選信號

return 0;
}

0 － 7位：字節(jié)在上半部、下半部及OOB內(nèi)的偏移地址
8位：值為0代表對一頁內(nèi)前256個(gè)字節(jié)進(jìn)行尋址，值為1代表對一頁內(nèi)后256個(gè)字節(jié)進(jìn)行尋址
9－13位：對頁進(jìn)行尋址
14－25位：對塊進(jìn)行尋址