NAND FLASH驱动程序

* drivers\mtd\nand\s3c2410.c

* drivers\mtd\nand\at91_nand.c

//

#include "linux/module.h"

#include "linux/types.h"

#include "linux/init.h"

#include "linux/kernel.h"

#include "linux/string.h"

#include "linux/ioport.h"

#include "linux/platform_device.h

#include "linux/delay.h"

#include "linux/err.h"

#include "linux/slab.h"

#include "linux/clk.h"

#include "linux/mtd/mtd.h"

#include "linux/mtd/nand.h"

#include "linux/mtd/nand_ecc.h"

#include "linux/mtd/partitions.h"

#include "asm/io.h"

#include "asm/arch/regs-nand.h"

#include "asm/arch/nand.h"

struct s3c_nand_regs {

unsigned long nfconf ;

unsigned long nfcont ;

unsigned long nfcmd ;

unsigned long nfaddr ;

unsigned long nfdata ;

unsigned long nfeccd0 ;

unsigned long nfeccd1 ;

unsigned long nfeccd ;

unsigned long nfstat ;

unsigned long nfestat0;

unsigned long nfestat1;

unsigned long nfmecc0 ;

unsigned long nfmecc1 ;

unsigned long nfsecc ;

unsigned long nfsblk ;

unsigned long nfeblk ;

};

static struct nand_chip *s3c_nand;

static struct mtd_info *s3c_mtd;

static struct s3c_nand_regs *s3c_nand_regs;

static struct mtd_partition s3c_nand_parts[] = {

[0] = {

.name = "bootloader",

.size = 0x00040000,

.offset = 0,

},

[1] = {

.name = "params",

.offset = MTDPART_OFS_APPEND, //紧跟着上一个分区

.size = 0x00020000,

},

[2] = {

.name = "kernel",

.offset = MTDPART_OFS_APPEND,

.size = 0x00200000,

},

[3] = {

.name = "root",

.offset = MTDPART_OFS_APPEND,

.size = MTDPART_SIZ_FULL, //剩下的所有空间都是"root"分区

}

};

static void s3c2440_select_chip(struct mtd_info *mtd, int chipnr)

{

if (chipnr == -1)

{

//取消选中: NFCONT[1]设为1

s3c_nand_regs->nfcont |= (1<1);

}

else

{

// 选中: NFCONT[1]设为0

s3c_nand_regs->nfcont &= ~(1<1);

}

}

static void s3c2440_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)

{

if (ctrl & NAND_CLE)

{

// 发命令: NFCMMD=dat

s3c_nand_regs->nfcmd = dat;

}

else

{

// 发地址: NFADDR=dat

s3c_nand_regs->nfaddr = dat;

}

}

static int s3c2440_dev_ready(struct mtd_info *mtd)

{

return (s3c_nand_regs->nfstat & (1<0));

}

static int s3c_nand_init(void)

{

struct clk *clk;

// 1. 分配一个nand_chip结构体

s3c_nand = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);

s3c_nand_regs = ioremap(0x4E000000, sizeof(struct s3c_nand_regs));

// 2. 设置nand_chip */

/ 设置nand_chip是给nand_scan函数使用的, 如果不知道怎么设置, 先看nand_scan怎么使用

/ 它应该提供:选中,发命令,发地址,发数据,读数据,判断状态的功能

//

s3c_nand->select_chip = s3c2440_select_chip;

s3c_nand->cmd_ctrl = s3c2440_cmd_ctrl;

s3c_nand->IO_ADDR_R = &s3c_nand_regs->nfdata;

s3c_nand->IO_ADDR_W = &s3c_nand_regs->nfdata;

s3c_nand->dev_ready = s3c2440_dev_ready;

s3c_nand->ecc.mode = NAND_ECC_SOFT;

// 3. 硬件相关的设置: 根据NAND FLASH的手册设置时间参数

// 使能NAND FLASH控制器的时钟

clk = clk_get(NULL, "nand");

clk_enable(clk);

// HCLK=100MHz

* TACLS: 发出CLE/ALE之后多长时间才发出nWE信号, 从NAND手册可知CLE/ALE与nWE可以同时发出,所以TACLS=0

* TWRPH0: nWE的脉冲宽度, HCLK x ( TWRPH0 + 1 ), 从NAND手册可知它要>=12ns, 所以TWRPH0>=1

* TWRPH1: nWE变为高电平后多长时间CLE/ALE才能变为低电平, 从NAND手册可知它要>=5ns, 所以TWRPH1>=0

//

#define TACLS 0

#define TWRPH0 1

#define TWRPH1 0

s3c_nand_regs->nfconf = (TACLS<12) | (TWRPH0<8) | (TWRPH1<4);

// NFCONT:

* BIT1-设为1, 取消片选

* BIT0-设为1, 使能NAND FLASH控制器

//

s3c_nand_regs->nfcont = (1<1) | (1<0);

// 4. 使用: nand_scan

s3c_mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);

s3c_mtd->owner = THIS_MODULE;