20150418 ram_flash驱动
2015-04-18 Lover雪儿
参考linux内核中的device/mtdram.c，编写了一个ram_flash驱动程序，说实在主要就是分配mtd_info结构体，初始化mtd_info结构体，以及提交结构体三步。
1 /* 利用内存来模拟flash操作
2 * 参考devices\mtdram.c
3 */
4 #include <linux/module.h>
5 #include <linux/slab.h>
6 #include <linux/ioport.h>
7 #include <linux/vmalloc.h>
8 #include <linux/init.h>
9 #include <linux/mtd/compatmac.h>
10 #include <linux/mtd/mtd.h>
11 #include <linux/mtd/mtdram.h>
12
13
14 #define RAM_FLASH_SIZE (10 * 1024 * 1024) //定义ram_flash的大小为10M
15 unsigned char *ram_flash_addr; //用于保存为ram_flash申请的内存的指针,也保存在mtd_info->priv中
16
17 //构建一个mtd_info结构体
18 static struct mtd_info *mtd_info;
19
20 //内存擦除函数
21 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr){
22 if (instr->addr + instr->len > mtd->size)
23 return -EINVAL;
24
25 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
26
27 instr->state = MTD_ERASE_DONE;
28 mtd_erase_callback(instr);
29
30 return 0;
31 }
32
33 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,size_t *retlen, void **virt, resource_size_t *phys){
34 if (from + len > mtd->size)
35 return -EINVAL;
36
37 /* can we return a physical address with this driver? */
38 if (phys)
39 return -EINVAL;
40
41 *virt = mtd->priv + from;
42 *retlen = len;
43 return 0;
44 }
45
46 static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len){
47
48 }
49
50 //重映射函数
51 static unsigned long ram_flash_get_unmapped_area(struct mtd_info *mtd,unsigned long len,unsigned long offset,unsigned long flags){
52 return (unsigned long) mtd->priv + offset;
53 }
54
55 //读函数
56 static int ram_flash_read(struct mtd_info *mtd, loff_t from, size_t len,size_t *retlen, u_char *buf){
57 if (from + len > mtd->size)
58 return -EINVAL;
59
60 memcpy(buf, mtd->priv + from, len);
61
62 *retlen = len;
63 return 0;
64 }
65
66 //写函数
67 static int ram_flash_write(struct mtd_info *mtd, loff_t to, size_t len,size_t *retlen, const u_char *buf){
68 if(to + len > mtd->size)
69 return -EINVAL;
70 memcpy((char *)mtd->priv + to, buf, len);
71 *retlen = len; //返回已经成功写入的大小
72 return 0;
73 }
74
75 //入口函数
76 static int ram_flash_init(void){
77 // 1.分配mtd_Info结构体
78 mtd_info = kmalloc(sizeof(struct mtd_info),GFP_KERNEL);
79 if(!mtd_info)
80 return -ENOMEM;
81
82 // 2.申请ram_flash的内存大小
83 ram_flash_addr = vmalloc(RAM_FLASH_SIZE); //申请内存
84
85 // 3.初始化mtd_info结构体
86 mtd_info->name = "ram_flash_device"; //名字
87 mtd_info->type = MTD_RAM; //1设备类型为RAM,定义在 mtd\mtd-abi.h中
88 mtd_info->flags = MTD_CAP_RAM; //标志，通用
89 mtd_info->size = RAM_FLASH_SIZE; //大小
90 mtd_info->writesize = 1;
91 mtd_info->erasesize = RAM_FLASH_SIZE;
92 mtd_info->priv = ram_flash_addr; //内存地址
93
94 mtd_info->owner = THIS_MODULE;
95 mtd_info->erase = ram_flash_erase; //从此开始关联一些操作函数
96 mtd_info->point = ram_flash_point;
97 mtd_info->unpoint = ram_flash_unpoint;
98 mtd_info->get_unmapped_area = ram_flash_get_unmapped_area;
99 mtd_info->read = ram_flash_read;
100 mtd_info->write = ram_flash_write;
101
102 // 4.注册mtd结构体
103 add_mtd_device(mtd_info); //整块flash只作为一个分区，使用add_mtd_device就够了
104
105 // 5.清除，初始化ram_flash,内容全部为FF表示初始化成功
106 memset(mtd_info->priv,0xff,RAM_FLASH_SIZE);
107
108 return 0;
109 }
110 //出口函数
111 static void ram_flash_exit(void){
112 if(mtd_info){
113 del_mtd_device(mtd_info);
114 vfree(mtd_info->priv);
115 kfree(mtd_info);
116 }
117 }
118
119 module_init(ram_flash_init);
120 module_exit(ram_flash_exit);
121 MODULE_AUTHOR("Lover雪儿");
122 MODULE_LICENSE("GPL");
ram_flash1.c
测试：
增加flash的分区：
由于前面程序总注册mtd结构体使用的是add_mtd_device函数，它是将整块flash当做一个分区，为了为了实现多分区，我们此处须使用add_mtd_partitions函数来注册mtd_info结构体。
1 /* 利用内存来模拟flash操作
2 * 参考devices\mtdram.c
3 */
4 #include <linux/module.h>
5 #include <linux/slab.h>
6 #include <linux/ioport.h>
7 #include <linux/vmalloc.h>
8 #include <linux/init.h>
9 #include <linux/mtd/compatmac.h>
10 #include <linux/mtd/mtd.h>
11 #include <linux/mtd/mtdram.h>
12
13
14 #define RAM_FLASH_SIZE (10 * 1024 * 1024) //定义ram_flash的大小为10M
15 unsigned char *ram_flash_addr; //用于保存为ram_flash申请的内存的指针,也保存在mtd_info->priv中
16
17 //构建一个mtd_info结构体
18 static struct mtd_info *mtd_info;
19
20
21 //定义分区表
22 static struct mtd_partition ram_flash_part[] = {
23 [0] = {
24 .name = "first_part",
25 .offset = 0,
26 .size = 0x200000, //2M
27 },
28 [1] = {
29 .name = "second_part",
30 .offset = MTDPART_OFS_APPEND, //紧跟着上一个分区
31 .size = 0x200000, //2M
32 },
33 [2] = {
34 .name = "third_part",
35 .offset = MTDPART_OFS_APPEND, //紧跟着上一个分区
36 .size = MTDPART_SIZ_FULL, //6M
37 },
38 };
39
40
41 //内存擦除函数
42 static int ram_erase(struct mtd_info *mtd, struct erase_info *instr){
43 if (instr->addr + instr->len > mtd->size)
44 return -EINVAL;
45
46 memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
47
48 instr->state = MTD_ERASE_DONE;
49 mtd_erase_callback(instr);
50
51 return 0;
52 }
53
54 static int ram_point(struct mtd_info *mtd, loff_t from, size_t len,size_t *retlen, void **virt, resource_size_t *phys){
55 if (from + len > mtd->size)
56 return -EINVAL;
57
58 /* can we return a physical address with this driver? */
59 if (phys)
60 return -EINVAL;
61
62 *virt = mtd->priv + from;
63 *retlen = len;
64 return 0;
65 }
66
67 static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len){
68
69 }
70
71 //重映射函数
72 static unsigned long ram_flash_get_unmapped_area(struct mtd_info *mtd,unsigned long len,unsigned long offset,unsigned long flags){
73 return (unsigned long) mtd->priv + offset;
74 }
75
76 //读函数
77 static int ram_flash_read(struct mtd_info *mtd, loff_t from, size_t len,size_t *retlen, u_char *buf){
78 if (from + len > mtd->size)
79 return -EINVAL;
80
81 memcpy(buf, mtd->priv + from, len);
82
83 *retlen = len;
84 return 0;
85 }
86
87 //写函数
88 static int ram_flash_write(struct mtd_info *mtd, loff_t to, size_t len,size_t *retlen, const u_char *buf){
89 if(to + len > mtd->size)
90 return -EINVAL;
91 memcpy((char *)mtd->priv + to, buf, len);
92 *retlen = len; //返回已经成功写入的大小
93 return 0;
94 }
95
96 //入口函数
97 static int ram_flash_init(void){
98 // 1.分配mtd_Info结构体
99 mtd_info = kmalloc(sizeof(struct mtd_info),GFP_KERNEL);
100 if(!mtd_info)
101 return -ENOMEM;
102
103 // 2.申请ram_flash的内存大小
104 ram_flash_addr = vmalloc(RAM_FLASH_SIZE); //申请内存
105
106 // 3.初始化mtd_info结构体
107 mtd_info->name = "ram_flash_device"; //名字
108 mtd_info->type = MTD_RAM; //1设备类型为RAM,定义在 mtd\mtd-abi.h中
109 mtd_info->flags = MTD_CAP_RAM; //标志，通用
110 mtd_info->size = RAM_FLASH_SIZE; //大小
111 mtd_info->writesize = 1;
112 mtd_info->erasesize = RAM_FLASH_SIZE;
113 mtd_info->priv = ram_flash_addr; //内存地址
114
115 mtd_info->owner = THIS_MODULE;
116 mtd_info->erase = ram_flash_erase; //从此开始关联一些操作函数
117 mtd_info->point = ram_flash_point;
118 mtd_info->unpoint = ram_flash_unpoint;
119 mtd_info->get_unmapped_area = ram_flash_get_unmapped_area;
120 mtd_info->read = ram_flash_read;
121 mtd_info->write = ram_flash_write;
122
123 // 4.注册mtd结构体
124 //add_mtd_device(mtd_info); //整块flash只作为一个分区，使用add_mtd_device就够了
125 add_mtd_partitions(mtd_info,ram_flash_part,3); //三个分区
126 // 5.清除，初始化ram_flash,内容全部为FF表示初始化成功
127 memset(mtd_info->priv,0xff,RAM_FLASH_SIZE);
128
129 return 0;
130 }
131 //出口函数
132 static void ram_flash_exit(void){
133 if(mtd_info){
134 //del_mtd_device(mtd_info);
135 del_mtd_partitions(mtd_info);
136 vfree(mtd_info->priv);
137 kfree(mtd_info);
138 }
139 }
140
141 module_init(ram_flash_init);
142 module_exit(ram_flash_exit);
143 MODULE_AUTHOR("Lover雪儿");
144 MODULE_LICENSE("GPL");
ram_flash2.c
使用mtd的flash-erase
下载： mtd-utils_1.5.1.orig.tar.gz
http://ftp.debian.org/debian/pool/main/m/mtd-utils/
在编译的过程中，你或许会遇到下面的问题：
1 (In compile process, you will meet the following problem.) 2 3 1. sys/acl.h: No such file or directory 4 --> sudo apt-get install libacl1-dev 5 6 2. compr_lzo.c:29:23: error: lzo/lzo1x.h: No such file or directory 7 --> sudo apt-get install liblzo-dev (Maybe use liblzo2-dev replace it) 8 9 3. uuid/uuid.h: No such file or directory 10 --> sudo apt-get install uuid-dev
时间： 2024-10-05 04:19:25