S5PV210(TQ210)学习笔记——Nand flash驱动编写（转）

       跟裸机程序一样，S5PV210的Nand flash模块跟S3C2440的Nand flash模块非常相似，如果不引入ECC，驱动程序的编写也非常简单，具体的分析及编写过程强烈推荐观看韦东山老师的视频教程，我是使用的Linux-3.8.6（Linux-3.8.3也一样）内核，驱动的API函数有些变化，不过原理是相通的，稍微看一下内核源码并参考下其他平台的相关代码就可以自己写出Nand flash驱动了，下面是Nand flash驱动的源码，没有启用ECC，当然，你也可以改成软件ECC，但是我的觉得既然软件ECC不如HWECC快，我就采用硬件ECC吧，我会在下篇文章中加入HWECC。

1. [plain] view plaincopy在CODE上查看代码片派生到我的代码片
   
2. #include <linux/module.h>  
   
3. #include <linux/platform_device.h>  
   
4. #include <linux/clk.h>  
   
5. #include <linux/io.h>  
   
6. #include <linux/slab.h>  
   
7. #include <linux/mtd/mtd.h>  
   
8. #include <linux/mtd/nand.h>  
   
9. #include <linux/mtd/partitions.h>  
   
10.   
    
11. struct s5p_nand_regs{  
    
12.     unsigned long nfconf;  
    
13.     unsigned long nfcont;  
    
14.     unsigned long nfcmmd;  
    
15.     unsigned long nfaddr;  
    
16.     unsigned long nfdata;  
    
17.     unsigned long nfmeccd0;  
    
18.     unsigned long nfmeccd1;  
    
19.     unsigned long nfseccd;  
    
20.     unsigned long nfsblk;  
    
21.     unsigned long nfeblk;  
    
22.     unsigned long nfstat;  
    
23.     unsigned long nfeccerr0;  
    
24.     unsigned long nfeccerr1;  
    
25.     unsigned long nfmecc0;  
    
26.     unsigned long nfmecc1;  
    
27.     unsigned long nfsecc;  
    
28.     unsigned long nfmlcbitpt;  
    
29. };  
    
30.   
    
31. struct s5p_nand_ecc{  
    
32.     unsigned long nfeccconf;  
    
33.     unsigned long nfecccont;  
    
34.     unsigned long nfeccstat;  
    
35.     unsigned long nfeccsecstat;  
    
36.     unsigned long nfeccprgecc0;  
    
37.     unsigned long nfeccprgecc1;  
    
38.     unsigned long nfeccprgecc2;  
    
39.     unsigned long nfeccprgecc3;  
    
40.     unsigned long nfeccprgecc4;  
    
41.     unsigned long nfeccprgecc5;  
    
42.     unsigned long nfeccprgecc6;  
    
43.     unsigned long nfeccerl0;  
    
44.     unsigned long nfeccerl1;  
    
45.     unsigned long nfeccerl2;  
    
46.     unsigned long nfeccerl3;  
    
47.     unsigned long nfeccerl4;  
    
48.     unsigned long nfeccerl5;  
    
49.     unsigned long nfeccerl6;  
    
50.     unsigned long nfeccerl7;  
    
51.     unsigned long nfeccerp0;  
    
52.     unsigned long nfeccerp1;  
    
53.     unsigned long nfeccerp2;  
    
54.     unsigned long nfeccerp3;  
    
55.     unsigned long nfeccconecc0;  
    
56.     unsigned long nfeccconecc1;  
    
57.     unsigned long nfeccconecc2;  
    
58.     unsigned long nfeccconecc3;  
    
59.     unsigned long nfeccconecc4;  
    
60.     unsigned long nfeccconecc5;  
    
61.     unsigned long nfeccconecc6;  
    
62. };  
    
63.   
    
64. static struct nand_chip *nand_chip;  
    
65. static struct mtd_info *s5p_mtd_info;  
    
66. static struct s5p_nand_regs *s5p_nand_regs;  
    
67. static struct s5p_nand_ecc  *s5p_nand_ecc;  
    
68. static struct clk *s5p_nand_clk;  
    
69.   
    
70. static struct mtd_partition s5p_nand_partions[] = {  
    
71.     [0] = {  
    
72.         .name   = "bootloader",  
    
73.         .offset = 0,  
    
74.         .size   = SZ_1M,  
    
75.     },  
    
76.   
    
77.     [1] = {  
    
78.         .name   = "kernel",  
    
79.         .offset = MTDPART_OFS_APPEND,  
    
80.         .size   = 5*SZ_1M,  
    
81.     },  
    
82.   
    
83.     [2] = {  
    
84.         .name   = "rootfs",  
    
85.         .offset = MTDPART_OFS_APPEND,  
    
86.         .size   = MTDPART_SIZ_FULL,  
    
87.     },  
    
88. };  
    
89.   
    
90. static void s5p_nand_select_chip(struct mtd_info *mtd, int chipnr){  
    
91.     if(chipnr == -1){  
    
92.         s5p_nand_regs->nfcont |= (1<<1);  
    
93.     }  
    
94.     else{  
    
95.         s5p_nand_regs->nfcont &= ~(1<<1);  
    
96.     }  
    
97. }  
    
98.   
    
99. static void s5p_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)  
    
100. {  
     
101.     if (ctrl & NAND_CLE){  
     
102.         s5p_nand_regs->nfcmmd = cmd;  
     
103.     }  
     
104.     else{  
     
105.         s5p_nand_regs->nfaddr = cmd;  
     
106.     }  
     
107. }  
     
108.   
     
109. static int s5p_nand_ready(struct mtd_info *mtd){  
     
110.     return (s5p_nand_regs->nfstat & 0x1);  
     
111. }  
     
112.   
     
113. static int s5p_nand_probe(struct platform_device *pdev){  
     
114.     int ret = 0;  
     
115.     struct resource *mem;  
     
116.     //硬件部分初始化  
     
117.     mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);  
     
118.     if (!mem) {  
     
119.         dev_err(&pdev->dev, "can't get I/O resource mem\n");  
     
120.         return -ENXIO;  
     
121.     }  
     
122.       
     
123.     s5p_nand_regs = (struct s5p_nand_regs *)ioremap(mem->start, resource_size(mem));  
     
124.     if (s5p_nand_regs == NULL) {  
     
125.         dev_err(&pdev->dev, "ioremap failed\n");  
     
126.         ret = -EIO;  
     
127.         goto err_exit;  
     
128.     }  
     
129.   
     
130.     s5p_nand_ecc = (struct s5p_nand_ecc *)ioremap(0xB0E20000, sizeof(struct s5p_nand_ecc));  
     
131.     if(s5p_nand_ecc == NULL){  
     
132.         dev_err(&pdev->dev, "ioremap failed\n");  
     
133.         ret = -EIO;  
     
134.         goto err_iounmap;  
     
135.     }  
     
136.       
     
137.     s5p_nand_clk = clk_get(&pdev->dev, "nand");  
     
138.     if(s5p_nand_clk == NULL){  
     
139.         dev_dbg(&pdev->dev, "get clk failed\n");  
     
140.         ret = -ENODEV;  
     
141.         goto err_iounmap;  
     
142.     }  
     
143.   
     
144.     clk_enable(s5p_nand_clk);  
     
145.       
     
146.     s5p_nand_regs->nfconf = (3<<12)|(5<<8)|(3<<4)|(1<<1);  
     
147.     s5p_nand_regs->nfcont |= 3;  
     
148.   
     
149.     //分配驱动相关结构体  
     
150.     nand_chip = (struct nand_chip *)kzalloc(sizeof(struct nand_chip), GFP_KERNEL);  
     
151.     if(nand_chip == NULL){  
     
152.         dev_err(&pdev->dev, "failed to allocate nand_chip structure\n");  
     
153.         ret = -ENOMEM;  
     
154.         goto err_clk_put;  
     
155.     }  
     
156.   
     
157.     s5p_mtd_info = (struct mtd_info *)kzalloc(sizeof(struct mtd_info), GFP_KERNEL);  
     
158.     if(s5p_mtd_info == NULL){  
     
159.         dev_err(&pdev->dev, "failed to allocate mtd_info structure\n");  
     
160.         ret = -ENOMEM;  
     
161.         goto err_free_chip;  
     
162.     }  
     
163.   
     
164.     //设置驱动相关结构体  
     
165.     nand_chip->select_chip = s5p_nand_select_chip;  
     
166.     nand_chip->cmd_ctrl    = s5p_nand_cmd_ctrl;  
     
167.     nand_chip->IO_ADDR_R   = &s5p_nand_regs->nfdata;  
     
168.     nand_chip->IO_ADDR_W   = &s5p_nand_regs->nfdata;  
     
169.     nand_chip->dev_ready   = s5p_nand_ready;  
     
170.     nand_chip->ecc.mode       = NAND_ECC_SOFT;  
     
171.       
     
172.     s5p_mtd_info->priv = nand_chip;  
     
173.     s5p_mtd_info->owner = THIS_MODULE;  
     
174.   
     
175.     //扫描Nand flash 设备  
     
176.     if(nand_scan(s5p_mtd_info, 1)){  
     
177.         dev_dbg(&pdev->dev, "nand scan error\n");  
     
178.         goto err_free_info;  
     
179.     }  
     
180.   
     
181.     //添加分区信息  
     
182.     ret = mtd_device_parse_register(s5p_mtd_info, NULL, NULL, s5p_nand_partions, ARRAY_SIZE(s5p_nand_partions));  
     
183.     if(!ret)  
     
184.         return 0;  
     
185.   
     
186. err_free_info:  
     
187.     kfree(s5p_mtd_info);  
     
188. err_free_chip:  
     
189.     kfree(nand_chip);  
     
190. err_clk_put:  
     
191.     clk_disable(s5p_nand_clk);  
     
192.     clk_put(s5p_nand_clk);  
     
193. err_iounmap:  
     
194.     //if(s5p_nand_ecc == NULL)  
     
195.     //  iounmap(s5p_nand_ecc);  
     
196.     if(s5p_nand_regs == NULL)  
     
197.         iounmap(s5p_nand_regs);  
     
198. err_exit:  
     
199.     return ret;  
     
200. }  
     
201.   
     
202. static int s5p_nand_remove(struct platform_device *pdev){  
     
203.     nand_release(s5p_mtd_info);  
     
204.     kfree(s5p_mtd_info);  
     
205.     kfree(nand_chip);  
     
206.   
     
207.     clk_disable(s5p_nand_clk);  
     
208.     clk_put(s5p_nand_clk);  
     
209.   
     
210.     if(s5p_nand_regs == NULL)  
     
211.         iounmap(s5p_nand_regs);  
     
212.     return 0;  
     
213. }  
     
214.   
     
215. static struct platform_driver s5p_nand_drv = {  
     
216.     .driver = {  
     
217.         .owner = THIS_MODULE,  
     
218.         .name = "s5p-nand",  
     
219.     },  
     
220.     .probe = s5p_nand_probe,  
     
221.     .remove = s5p_nand_remove,  
     
222. };  
     
223.   
     
224. module_platform_driver(s5p_nand_drv);  
     
225. MODULE_LICENSE("GPL");  

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源码都在上面，具体的原理还是参考视频或者其他资料，这里就不多说了，如果有任何问题，欢迎留言讨论。

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本文作者：girlkoo