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ARM·Nand Flash的控制

作者： 时间：2016-11-24 来源：网络
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static void s3c2440_write_addr_lp(unsigned int addr)
{
int i;
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFADDR;
int col, page;
col = addr & NAND_BLOCK_MASK_LP;
page = addr / NAND_SECTOR_SIZE_LP;
*p = col & 0xff;
for(i=0; i<10; i++);
*p = (col >> 8) & 0x0f;
for(i=0; i<10; i++);
*p = page & 0xff;
for(i=0; i<10; i++);
*p = (page >> 8) & 0xff;
for(i=0; i<10; i++);
*p = (page >> 16) & 0x03;
for(i=0; i<10; i++);
}
static unsigned char s3c2440_read_data(void)
{
volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFDATA;
return *p;
}
static void nand_reset(void)
{
nand_chip.nand_reset();
}
static void wait_idle(void)
{
nand_chip.wait_idle();
}
static void nand_select_chip(void)
{
int i;
nand_chip.nand_select_chip();
for(i=0; i<10; i++);
}
static void nand_deselect_chip(void)
{
nand_chip.nand_deselect_chip();
}
static void write_cmd(int cmd)
{
nand_chip.write_cmd(cmd);
}
static void write_addr(unsigned int addr)
{
nand_chip.write_addr(addr);
}
static unsigned char read_data(void)
{
return nand_chip.read_data();
}
void nand_init(void)
{
#define TACLS 0
#define TWRPH0 3
#define TWRPH1 0
if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
{
nand_chip.nand_reset = s3c2410_nand_reset;
nand_chip.wait_idle = s3c2410_wait_idle;
nand_chip.nand_select_chip = s3c2410_nand_select_chip;
nand_chip.nand_deselect_chip = s3c2410_nand_deselect_chip;
nand_chip.write_cmd = s3c2410_write_cmd;
nand_chip.write_addr = s3c2410_write_addr;
nand_chip.read_data = s3c2410_read_data;
s3c2410nand->NFCONF = (1<<15)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);
}
else
{
nand_chip.nand_reset = s3c2440_nand_reset;
nand_chip.wait_idle = s3c2440_wait_idle;
nand_chip.nand_select_chip = s3c2440_nand_select_chip;
nand_chip.nand_deselect_chip = s3c2440_nand_deselect_chip;
nand_chip.write_cmd = s3c2440_write_cmd;
#ifdef LARGER_NAND_PAGE
nand_chip.write_addr = s3c2440_write_addr_lp;
#else
nand_chip.write_addr = s3c2440_write_addr;
#endif
nand_chip.read_data = s3c2440_read_data;
s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
s3c2440nand->NFCONT = (1<<4)|(1<<1)|(1<<0);
}
nand_reset();
}
void nand_read(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
#ifdef LARGER_NAND_PAGE
if ((start_addr & NAND_BLOCK_MASK_LP) || (size & NAND_BLOCK_MASK_LP)) {
return ;
}
#else
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
return ;
}
#endif
nand_select_chip();
for(i=start_addr; i < (start_addr + size);) {
write_cmd(0);
write_addr(i);
#ifdef LARGER_NAND_PAGE
write_cmd(0x30);
#endif
wait_idle();
#ifdef LARGER_NAND_PAGE
for(j=0; j < NAND_SECTOR_SIZE_LP; j++, i++) {
#else
for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
#endif
*buf = read_data();
buf++;
}
}
nand_deselect_chip();
return ;
}
这一长串红色的代码也就是Nand Flash的初始化，我们可以仔细的分析一下Nand的控制寄存器
再看代码，从head.s中也就跳转到了nand.c中的灰色部分 ；
1）S3C2410和S3C2440的一个判断
2）定义了一个结构体
{
nand_chip.nand_reset = s3c2440_nand_reset;
nand_chip.wait_idle = s3c2440_wait_idle;
nand_chip.nand_select_chip = s3c2440_nand_select_chip;
nand_chip.nand_deselect_chip = s3c2440_nand_deselect_chip;
nand_chip.write_cmd = s3c2440_write_cmd;
#ifdef LARGER_NAND_PAGE
nand_chip.write_addr = s3c2440_write_addr_lp;
#else
nand_chip.write_addr = s3c2440_write_addr;
#endif
nand_chip.read_data = s3c2440_read_data;
s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
s3c2440nand->NFCONT = (1<<4)|(1<<1)|(1<<0);
}
*上面定义了结构体，右边一列都是s3c2440中可以调用的函数 ；
*在设置时序中：【NFCONF】寄存器
使能NAND Flash控制器，初始化ECC，禁止片选 ：【NFCONT】寄存器
（我觉得了解一下就好了，还真的去看时序啊，那个老师都没说的清楚，估计是默认值）

【NFCONF】


【NFCONT】
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关键词： ARMNandFlas

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