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本帖最后由 xiang8000 于 2010-10-3 10:44 编辑
目前板子已经能够从Nand Flash启动,并且终端有输出,其输出字样为:
U-Boot 2009.08 (10月 03 2010 - 04:08:59)
DRAM: 64 MB
Flash: 2 MB
NAND: No NAND device found!!!
0 MiB
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
2440 #
然后键入nand help 命令,终端输出为:
2440 # nand help
nand - NAND sub-system
Usage:
nand info - show available NAND devices
nand device [dev] - show or set current device
nand read - addr off|partition size
nand write - addr off|partition size
read/write 'size' bytes starting at offset 'off'
to/from memory address 'addr', skipping bad blocks.
nand erase [clean] [off size] - erase 'size' bytes from
offset 'off' (entire device if not specified)
nand bad - show bad blocks
nand dump[.oob] off - dump page
nand scrub - really clean NAND erasing bad blocks (UNSAFE)
nand markbad off [...] - mark bad block(s) at offset (UNSAFE)
nand biterr off - make a bit error at offset (UNSAFE)
2440 #
虽然能使用nand help命令,但是nand info命令却不能使用,键入后
2440 # nand info
2440 #
无任何显示,并返回等待输入
如果此时输入nand bad,会显示 没有驱动字样
2440 # nand bad
no devices available
2440 #
既然我的u-boot已经可以从nand flash启动并有了终端输出,那么板子应该已经识别到了nandflash了呀,为什么这些nand info等命令我却不能使用呢?另外环境变量也不能保存到NAND FLASH中,问题出在什么地方?望老师指教说明一下,是那部分代码存在问题,不胜感激!
这是我这里关于添加NAND FLASH启动相关的所有代码,根据别人blog一步一步进行而来,是否是有什么地方有所遗漏?已仔细检查数次,blog中所提到的地方已经都做了添加或修改,进度和blog一致无遗漏,是否blog有些步骤没有提及所以我这边也就有问题,老师费心了
blog如下(其也是 K9F1208U0B 64M nand flash + 2440)
首先,在include/configs/my2440.h头文件中定义Nand要用到的宏和寄存器,如下: #gedit include/configs/my2440.h //在文件末尾加入以下Nand Flash相关定义
#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 STACK_BASE 0x33F00000 //定义堆栈的地址
#define STACK_SIZE 0x8000 //堆栈的长度大小
#define oNFCONF 0x00 //相对Nand配置寄存器基地址的偏移量,还是配置寄存器的基地址
#define oNFCONT 0x04 //相对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 //得到地址寄存器的基地址(0x4E00000c)
#define oNFDATA 0x10 //得到数据寄存器的基地址(0x4E000010)
#define oNFCMD 0x08 //可得到指令寄存器的基地址(0x4E000008)
#define oNFSTAT 0x20 //可得到状态寄存器的基地址(0x4E000020)
#define oNFECC 0x2c //可得到ECC寄存器的基地址(0x4E00002c)
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 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
//下面添加2440中u-boot从Nand Flash启动
#ifdef CONFIG_S3C2440_NAND_BOOT
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, #0x30000 //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
_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
再次,在board/samsung/my2440/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/samsung/my2440/nand_read.c //新建一个nand_read.c文件,记得保存
#include <config.h>
#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 ) //通过偏移量还是得到配置寄存器基地址
#define NFCONT __REGi(NF_BASE + 0x4 ) //通过偏移量得到控制寄存器基地址
#define NFCMD __REGb(NF_BASE + 0x8 ) //通过偏移量得到指令寄存器基地址
#define NFADDR __REGb(NF_BASE + 0xC ) //通过偏移量得到地址寄存器基地址
#define NFDATA __REGb(NF_BASE + 0x10) //通过偏移量得到数据寄存器基地址
#define NFSTAT __REGb(NF_BASE + 0x20) //通过偏移量得到状态寄存器基地址
#define NAND_CHIP_ENABLE (NFCONT &= ~(1<<1)) //Nand片选使能
#define NAND_CHIP_DISABLE (NFCONT |= (1<<1)) //取消Nand片选
#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, int size)
{
int i, j;
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK))
{
return -1; //地址或长度不对齐
}
NAND_CHIP_ENABLE; //选中Nand片选
for(i=start_addr; i < (start_addr + size);)
{
//发出READ0指令
NAND_CLEAR_RB;
NFCMD = 0;
//对Nand进行寻址
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; //取消片选信号
return 0;
}
然后,在board/samsung/my2440/Makefile中添加nand_read.c的编译选项,使他编译到u-boot中,如下: COBJS := my2440.o flash.o nand_read.o
修改cpu/arm920t/u-boot.lds
.text :
{
cpu/arm920t/start.o (.text)
board/samsung/my2440/lowlevel_init.o (.text) //添加
board/samsung/my2440/nand_read.o (.text) //添加
*(.text)
}
移植到这里,nandflash终端会有输出,但是尚不能使用nand help命令 |
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