mini2440 简单nandflash驱动代码记录（2.6.32.2内核）

#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/cpufreq.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 <plat/regs-nand.h>
#include <plat/nand.h>

static struct nand_chip *mini2440_nand;
static struct mtd_info *mini2440_mtd_info;

static struct nand_regs_t{
	unsigned long NFCONF;
	unsigned long NFCONT;
	unsigned long NFCMD;
	unsigned long NFADDR;
	unsigned long NFDATA;
	unsigned long NFMECCD0;
	unsigned long NFMECCD1;
	unsigned long NFSECCD;
	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 volatile struct nand_regs_t *nand_regs;


static void grh_select_chip(struct mtd_info *mtd,int chipnr){
	if(-1 == chipnr){ //取消选中nfcont[1] = 1
		nand_regs->NFCONT |= (1<<1);
	}
	else{ //选中芯片 nfcont[1] = 0
		nand_regs->NFCONT &= ~(1<<1);
	}
}

static void grh_cmd_ctrl(struct mtd_info *mtd,int dat,unsigned int ctrl){
	if(ctrl & NAND_CLE){ //发送命令 nfcmmd = dat
		nand_regs->NFCMD = dat;
	}
	else{ //发送地址 nfaddr = dat
		nand_regs->NFADDR = dat;
	}
}

static int grh_dev_ready(struct mtd_info *mdt){
	//return nfstat[0]
	return nand_regs->NFSTAT &(1<<0);
}

//falsh分区表
static struct mtd_partition grh_nand_parts[] = {
	[0] = {
		.name	= "grh_supervivi",.size	= 0x00040000,.offset	= 0,},[1] = {
		.name	= "grh_param",.offset = 0x00040000,.size	= 0x00020000,[2] = {
		.name	= "grh_Kernel",.offset = 0x00060000,.size	= 0x00500000,[3] = {
		.name	= "grh_root",.offset = 0x00560000,.size	= 1024 * 1024 * 1024,//
	},[4] = {
		.name	= "grh_nand",.offset = 0x00000000,//
	}
};


static int nand_init(void){
	struct clk *clk;
	
	/*分配nand_chip结构体
	  该结构体里面需要提供对nandflash的硬件操作(发命令，发数据，读数据，复位，选通等)的
	  具体实现，mtd_info实现了怎么用命令来操作flash,而nand_chip就得在更低一层对命令进行实现
	*/
	mini2440_nand = kzalloc(sizeof(struct nand_chip),GFP_KERNEL);
	nand_regs = ioremap(0x4e000000,sizeof(struct nand_regs_t));

	//设置参数
	mini2440_nand->select_chip = grh_select_chip; //设置选中芯片的函数
	mini2440_nand->cmd_ctrl = grh_cmd_ctrl; //设置发送命令和地址的函数
	mini2440_nand->IO_ADDR_R = &(nand_regs->NFDATA); //nfdata虚拟地址
	mini2440_nand->IO_ADDR_W = &(nand_regs->NFDATA); //nfdata虚拟地址
	mini2440_nand->dev_ready = grh_dev_ready; //判断芯片是否就绪的函数
	mini2440_nand->ecc.mode = NAND_ECC_SOFT; //软件生成ECC校验码，存入OOB区
	
	//使能nandflash控制器的时钟,才能操作相关的寄存器
	clk = clk_get(NULL,"nand");
	clk_enable(clk);

	//设置硬件相关的时间参数
	nand_regs->NFCONF = 0<<12; //TACLS=0
	nand_regs->NFCONF |= (1<<8); //TWRPH0=1
	nand_regs->NFCONF |= (0<<4); //TWRPH1=0

	nand_regs->NFCONT |= (1<<1); //先不选中芯片
	nand_regs->NFCONT |= (1<<0); //使能nandflash控制器

	//使用nand_chip
	mini2440_mtd_info = kzalloc(sizeof(struct mtd_info),GFP_KERNEL);
	mini2440_mtd_info->owner = THIS_MODULE;
	mini2440_mtd_info->priv = mini2440_nand;

	//扫描识别芯片构造mtd_info结构体,mtd_info确定了对flash进行读写需要怎么发送命令
	nand_scan(mini2440_mtd_info,1); 

	//add_mtd_partition划分flash的分区
	add_mtd_partitions(mini2440_mtd_info,grh_nand_parts,5);
	
	
	return 0;
}

static void nand_exit(void){
	iounmap(nand_regs);
	kfree(mini2440_nand);
	kfree(mini2440_mtd_info);
	return ;
}

module_init(nand_init);
module_exit(nand_exit);

MODULE_AUTHOR("GRH");
MODULE_VERSION("1.0");
MODULE_DESCRIPTION("NAND FLASH DRIVER");
MODULE_LICENSE("GPL");