平台:MINI2440
在目錄drivers\mtd\nand\下建立空的C檔案mynand.c
mynand.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 ; //Nandflash寄存器
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", //<span style="font-family: Arial, Helvetica, sans-serif;">mtd_partition </span>記錄目前Nandflash的分區有幾個,名字,大小,偏移量
.size = 0x00040000,
.offset = 0,
},
[1] = {
.name = "param", //啟動參數
.offset = 0x00040000,
.size = 0x00020000,
},
[2] = {
.name = "Kernel", //核心
.offset = 0x00060000,
.size = 0x00500000,
},
[3] = { //noinitrd root=/dev/mtdblock3 init=/linuxrc console=ttySAC0
.name = "root", //檔案系統的mtd分區一定要和它的實際位置一緻,這裡對應mtdblock3
.offset = 0x00560000,
.size = 1024 * 1024 * 1024,
},
[4] = {
.name = "nand", //可供使用者使用
.offset = 0x00000000,
.size = 1024 * 1024 * 1024,
}
};
static void s3c2440_select_chip(struct mtd_info *mtd, int chipnr)
{
if (chipnr == -1)
{
//不選中
s3c_nand_regs->nfcont |= (1<<1);
}
else
{
//選中
s3c_nand_regs->nfcont &= ~(1<<1);
}
}
static void s3c2440_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
{
if (ctrl & NAND_CLE)
{
//發送指令
s3c_nand_regs->nfcmd = dat;
}
else
{
//發送位址
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;
//配置設定nand_chip結構體
s3c_nand = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
s3c_nand_regs = ioremap(0x4E000000, sizeof(struct s3c_nand_regs));
//設定nand_chip
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;
//使能NAND控制器時鐘
clk = clk_get(NULL, "nand");
clk_enable(clk);
//檢視nandflash手冊
#define TACLS 0
#define TWRPH0 1
#define TWRPH1 0
s3c_nand_regs->nfconf = (TACLS<<12) | (TWRPH0<<8) | (TWRPH1<<4);
s3c_nand_regs->nfcont = (1<<1) | (1<<0);
s3c_mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
s3c_mtd->owner = THIS_MODULE;
s3c_mtd->priv = s3c_nand;
nand_scan(s3c_mtd, 1); //nand_scan會将我們寫的對于晶片的讀寫函數重載到nand_chip結構中去,并把mtd_info結構體中的函數用nand的函數來重載,實作mtd到 底層驅動之間的聯系,并且在nand_scan函數中通過讀取晶片的裝置号和廠家号自動在晶片清單中尋找相應的型号和參數,并将它注冊
add_mtd_partitions(s3c_mtd, s3c_nand_parts, 4);//注冊裝置函數。如果不分區,使用add_mtd_device函數,在mtdcore.c裡實作
return 0;
}
static void s3c_nand_exit(void)
{
del_mtd_partitions(s3c_mtd);
kfree(s3c_mtd);
iounmap(s3c_nand_regs);
kfree(s3c_nand);
}
module_init(s3c_nand_init);
module_exit(s3c_nand_exit);
MODULE_LICENSE("GPL");
将該驅動編譯到核心,在drivers\mtd\nand\下編輯Makefile
添加:
obj-$(CONFIG_MTD_NAND_TEST) += mynand.o
編輯drivers\mtd\nand\下Kconfig:
添加:
config MTD_NAND_TEST
tristate "NAND Flash TEST"
depends on ARCH_S3C2410 || ARCH_S3C64XX
配置核心:
注釋掉預設配置:NAND Flash support for Samsung S3C SoCs
選上NAND Flash TEST,儲存。
編譯生成zImage後燒寫到闆子,如果系統啟動過程中,挂載檔案系統不正常,就要檢查mtd分區“root”分區與檔案系統實際燒寫位置是否一緻。