NAND Flash驱动

硬件原理及分析

管脚说明

在U-BOOT上操作Nand Flash

NAND FLASH S3C2440

发命令 选中芯片

CLE设为高电平 NFCMMD=命令值

在DATA0~DATA7上输出命令值

发出一个写脉冲

发地址 选中芯片 NFADDR=地址值

ALE设为高电平

在DATA0~DATA7上输出地址值

发出一个写脉冲

发数据 选中芯片 NFDATA=数据值

ALE,CLE设为低电平

在DATA0~DATA7上输出数据值

发出一个写脉冲

读数据 选中芯片 val=NFDATA

发出读脉冲

读DATA0~DATA7的数据

OpenJTAG> help md

md [.b, .w, .l] address [# of objects]

- memory display

OpenJTAG> help mw

mw [.b, .w, .l] address value [count]

- write memory

•b        1字节

•W        2字节

•l        4字节

1. 读ID

2. 读内容: 读0地址的数据

使用UBOOT命令:

nand dump 0

Page 00000000 dump:

17 00 00 ea 14 f0 9f e5 14 f0 9f e5 14 f0 9f e5

ECC的作用

S3C2440-Nand Flash Controller Register

S3C2440-Nand Flash Memory Timing

K9F2G08U0C-Key Characteristic

K9F2G08U0C-Operation Timing

驱动程序

driver.c

1 /*
2 * SAMSUNG: K9F2G08U0C
3 * 参考：
4 * .linux-2.6.22.6driversmtdnands3c2410.c
5 * .linux-2.6.22.6driversmtdnandat91_nand.c
6 */
7 #include
8 #include
9 #include
10 #include
11 #include
12 #include
13 #include
14 #include
15 #include
16 #include
17 #include
18         
19 #include
20 #include
21 #include
22 #include
23         
24 #include
25         
26 #include
27 #include
28
29 struct regs_nand {
30         unsigned long         NFCONF;                
31         unsigned long        NFCONT;                 
32         unsigned long        NFCMMD;                 
33         unsigned long        NFADDR;                 
34         unsigned long        NFDATA;
35         unsigned long        NFMECCD0;
36         unsigned long        NFMECCD1;
37         unsigned long        NFSECCD;
38         unsigned long        NFSTAT;
39         unsigned long        NFESTAT0;         
40         unsigned long        NFESTAT1;
41         unsigned long        NFMECC0;                
42         unsigned long        NFMECC1;                        
43         unsigned long        NFSECC;                 
44         unsigned long        NFSBLK;                 
45         unsigned long        NFEBLK;
46 };
47
48 static struct nand_chip *nand;
49 static struct mtd_info *mtd;
50 static struct regs_nand *regs_nand;
51
52 //分区信息
53 static struct mtd_partition nand_parts[] = {
54         [0] = {
55                 .name         = 'bootloader',                        
56                 .size         = 0x00040000,                        
57                 .offset = 0,                                        /* offset within the master MTD space */
58         },
59
60         [1] = {
61                 .name         = 'params',                        
62                 .offset = MTDPART_OFS_APPEND,        //紧跟着上一个分区的大小
63                 .size         = 0x00020000,                        
64         },
65
66         [2] = {
67                 .name         = 'kernel',                                
68                 .offset = MTDPART_OFS_APPEND,        //紧跟着上一个分区的大小
69                 .size         = 0x00200000,                        
70         },
71
72         [3] = {
73                 .name         = 'root',                                
74                 .offset = MTDPART_OFS_APPEND,        //紧跟着上一个分区的大小
75                 .size         = MTDPART_SIZ_FULL,                
76         },
77 };
78
79 static void nand_select_chip(struct mtd_info *mtd, int chipnr)
80 {
81         if (chipnr == -1)
82         {
83                 //取消选中：NFCONT[1]:0
84                 regs_nand->NFCONT |= (1<<1);
85         }
86         else {
87                 //选中：NFCONT[1]:1
88                 regs_nand->NFCONT &= ~(1<<1);
89         }
90         return;
91 }
92
93 static void nand_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
94 {
95         if (ctrl & NAND_CLE)
96         {
97                 //发命令：NFCMMD=dat
98                 regs_nand->NFCMMD = dat;
99         }
100         else
101         {
102                 //发地址：NFADDR=dat
103                 regs_nand->NFADDR = dat;
104         }
105         return;
106 }
107
108 static int nand_dev_ready(struct mtd_info *mtd)
109 {
110         return (regs_nand->NFSTAT & (1<<0));
111 }
112
113
114 /* 1 出、入口函数 */
115 static int __init nand_init(void)
116 {
117         struct clk *clk;
118
119         /* 2 分配一个nand_chip结构体 */
120         nand = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
121         /******** 2 end ********/
122
123         regs_nand = ioremap(0x4E000000, sizeof(struct regs_nand));
124
125         /* 3 设置：nand_chip */
126         //提供：选中、发命令、发地址、发数据、读数据、判断状态的功能
127         nand->select_chip         = nand_select_chip;                //片选
128         nand->cmd_ctrl                = nand_cmd_ctrl;                //发命令
129         nand->IO_ADDR_R                = ®s_nand->NFDATA;        //读
130         nand->IO_ADDR_W                = ®s_nand->NFDATA;        //写
131         nand->dev_ready                = nand_dev_ready;                //Flash 状态(忙/空闲)
132         nand->ecc.mode                = NAND_ECC_SOFT;                //ecc软件校验
133         /******** 3 end ********/
134
135         /* 4 硬件相关的操作：时序 */
136         //使能时钟
137         clk = clk_get(NULL, 'nand');
138         clk_enable(clk);
139         
140 #define TACLS        0
141 #define TWRPH0        1
142 #define TWRPH1        0
143         //时间参数设置
144         regs_nand->NFCONF        = (TACLS<<12) | (TWRPH0<<8) | (TWRPH1<<4);
145
146         //控制---使能nand flash控制器，取消片选
147         regs_nand->NFCONT        = (1<<0) | (1<<1);
148         /******** 4 end ********/
149         
150
151         /* 5 使用：nand_scan */
152         mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
153         mtd->owner        = THIS_MODULE;
154         mtd->priv        = nand;                //私有数据
155         
156         nand_scan(mtd, 1);                //识别nand_flash，构造mtd_info结构体
157         /******** 5 end ********/
158
159
160         /* 6 添加分区：add_mtd_partitions */
161         add_mtd_partitions(mtd, nand_parts, 4);
162
163         //不分区的情形
164         //add_mtd_device(mtd);
165         /******** 6 end ********/
166
167         return 0;
168 }
169
170 static void __exit nand_exit(void)
171 {
172         del_mtd_partitions(mtd);
173         kfree(nand);
174         kfree(mtd);
175         iounmap(regs_nand);
176         return;
177 }
178
179 module_init(nand_init);
180 module_exit(nand_exit);
181 MODULE_LICENSE('GPL');
182 /******** 1 end ********/