大家好，又到了天嵌【嵌入式分享】的时间，相对于前几期【嵌入式分享】做的主要是TQ335X开发板的技术分享，本期决定做同是cortex-a8系列的TQ210开发板的技术分享。本期是关于TQ210开发板的Nand flash驱动编写，可能源码部分会比较多，本文由博主girlkoo编写，感谢他的分享。

　　跟裸机程序一样，S5PV210(TQ210)的Nand flash模块跟S3C2440(TQ2440)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，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。

#include  

#include  

#include  

#include  

#include  

#include  

#include  

#include  

struct s5p_nand_regs{  

   unsigned long nfconf;  

   unsigned long nfcont;  

   unsigned long nfcmmd;  

   unsigned long nfaddr;  

   unsigned long nfdata;  

   unsigned long nfmeccd0;  

   unsigned long nfmeccd1;  

   unsigned long nfseccd;  

   unsigned long nfsblk;  

   unsigned long nfeblk;  

   unsigned long nfstat;  

   unsigned long nfeccerr0;  

   unsigned long nfeccerr1;  

   unsigned long nfmecc0;  

   unsigned long nfmecc1;  

   unsigned long nfsecc;  

   unsigned long nfmlcbitpt;  

};  

struct s5p_nand_ecc{  

   unsigned long nfeccconf;  

   unsigned long nfecccont;  

   unsigned long nfeccstat;  

   unsigned long nfeccsecstat;  

   unsigned long nfeccprgecc0;  

   unsigned long nfeccprgecc1;  

   unsigned long nfeccprgecc2;  

   unsigned long nfeccprgecc3;  

   unsigned long nfeccprgecc4;  

   unsigned long nfeccprgecc5;  

   unsigned long nfeccprgecc6;  

   unsigned long nfeccerl0;  

   unsigned long nfeccerl1;  

   unsigned long nfeccerl2;  

   unsigned long nfeccerl3;  

   unsigned long nfeccerl4;  

   unsigned long nfeccerl5;  

   unsigned long nfeccerl6;  

   unsigned long nfeccerl7;  

   unsigned long nfeccerp0;  

   unsigned long nfeccerp1;  

   unsigned long nfeccerp2;  

   unsigned long nfeccerp3;  

   unsigned long nfeccconecc0;  

   unsigned long nfeccconecc1;  

   unsigned long nfeccconecc2;  

   unsigned long nfeccconecc3;  

   unsigned long nfeccconecc4;  

   unsigned long nfeccconecc5;  

   unsigned long nfeccconecc6;  

};  

static struct nand_chip *nand_chip;  

static struct mtd_info *s5p_mtd_info;  

static struct s5p_nand_regs *s5p_nand_regs;  

static struct s5p_nand_ecc  *s5p_nand_ecc;  

static struct clk *s5p_nand_clk;  

static struct mtd_partition s5p_nand_partions[] = {  

   [0] = {  

       .name   = "bootloader",  

       .offset = 0,  

       .size   = SZ_1M,  

   },  

   [1] = {  

       .name   = "kernel",  

       .offset = MTDPART_OFS_APPEND,  

       .size   = 5*SZ_1M,  

   },  

   [2] = {  

       .name   = "rootfs",  

       .offset = MTDPART_OFS_APPEND,  

       .size   = MTDPART_SIZ_FULL,  

   },  

};  

static void s5p_nand_select_chip(struct mtd_info *mtd, int chipnr){  

   if(chipnr == -1){  

       s5p_nand_regs->nfcont |= (1<<1);  

   }  

   else{  

       s5p_nand_regs->nfcont &= ~(1<<1);  

   }  

}  

static void s5p_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)  

{  

   if (ctrl & NAND_CLE){  

       s5p_nand_regs->nfcmmd = cmd;  

   }  

   else{  

       s5p_nand_regs->nfaddr = cmd;  

   }  

}  

static int s5p_nand_ready(struct mtd_info *mtd){  

   return (s5p_nand_regs->nfstat & 0x1);  

}  

static int s5p_nand_probe(struct platform_device *pdev){  

   int ret = 0;  

   struct resource *mem;  

   //硬件部分初始化  

   mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);  

   if (!mem) {  

       dev_err(&pdev->dev, "can't get I/O resource mem\n");  

       return -ENXIO;  

   }  

   s5p_nand_regs = (struct s5p_nand_regs *)ioremap(mem->start, resource_size(mem));  

   if (s5p_nand_regs == NULL) {  

       dev_err(&pdev->dev, "ioremap failed\n");  

       ret = -EIO;  

       goto err_exit;  

   }  

   s5p_nand_ecc = (struct s5p_nand_ecc *)ioremap(0xB0E20000, sizeof(struct s5p_nand_ecc));  

   if(s5p_nand_ecc == NULL){  

       dev_err(&pdev->dev, "ioremap failed\n");  

       ret = -EIO;  

       goto err_iounmap;  

   }  

   s5p_nand_clk = clk_get(&pdev->dev, "nand");  

   if(s5p_nand_clk == NULL){  

       dev_dbg(&pdev->dev, "get clk failed\n");  

       ret = -ENODEV;  

       goto err_iounmap;  

   }  

   clk_enable(s5p_nand_clk);  

   s5p_nand_regs->nfconf = (3<<12)|(5<<8)|(3<<4)|(1<<1);  

   s5p_nand_regs->nfcont |= 3;  

   //分配驱动相关结构体  

   nand_chip = (struct nand_chip *)kzalloc(sizeof(struct nand_chip), GFP_KERNEL);  

   if(nand_chip == NULL){  

       dev_err(&pdev->dev, "failed to allocate nand_chip structure\n");  

       ret = -ENOMEM;  

       goto err_clk_put;  

   }  

   s5p_mtd_info = (struct mtd_info *)kzalloc(sizeof(struct mtd_info), GFP_KERNEL);  

   if(s5p_mtd_info == NULL){  

       dev_err(&pdev->dev, "failed to allocate mtd_info structure\n");  

       ret = -ENOMEM;  

       goto err_free_chip;  

   }  

   //设置驱动相关结构体  

   nand_chip->select_chip = s5p_nand_select_chip;  

   nand_chip->cmd_ctrl    = s5p_nand_cmd_ctrl;  

   nand_chip->IO_ADDR_R   = &s5p_nand_regs->nfdata;  

   nand_chip->IO_ADDR_W   = &s5p_nand_regs->nfdata;  

   nand_chip->dev_ready   = s5p_nand_ready;  

   nand_chip->ecc.mode       = NAND_ECC_SOFT;  

   s5p_mtd_info->priv = nand_chip;  

   s5p_mtd_info->owner = THIS_MODULE;  

   //扫描Nand flash 设备  

   if(nand_scan(s5p_mtd_info, 1)){  

       dev_dbg(&pdev->dev, "nand scan error\n");  

       goto err_free_info;  

   }  

   //添加分区信息  

   ret = mtd_device_parse_register(s5p_mtd_info, NULL, NULL, s5p_nand_partions, ARRAY_SIZE(s5p_nand_partions));  

   if(!ret)  

       return 0;  

err_free_info:  

   kfree(s5p_mtd_info);  

err_free_chip:  

   kfree(nand_chip);  

err_clk_put:  

   clk_disable(s5p_nand_clk);  

   clk_put(s5p_nand_clk);  

err_iounmap:  

   //if(s5p_nand_ecc == NULL)  

   //  iounmap(s5p_nand_ecc);  

   if(s5p_nand_regs == NULL)  

       iounmap(s5p_nand_regs);  

err_exit:  

   return ret;  

}  

static int s5p_nand_remove(struct platform_device *pdev){  

   nand_release(s5p_mtd_info);  

   kfree(s5p_mtd_info);  

   kfree(nand_chip);  

   clk_disable(s5p_nand_clk);  

   clk_put(s5p_nand_clk);  

   if(s5p_nand_regs == NULL)  

       iounmap(s5p_nand_regs);  

   return 0;  

}  

static struct platform_driver s5p_nand_drv = {  

   .driver = {  

       .owner = THIS_MODULE,  

       .name = "s5p-nand",  

   },  

   .probe = s5p_nand_probe,  

   .remove = s5p_nand_remove,  

};  

module_platform_driver(s5p_nand_drv);  

MODULE_LICENSE("GPL");  

　　上述源码为嵌入式爱好者分享，如有更新，请咨询相关客服与销售人员，以便更新与开发。

　　操作所使用的硬件：

　　TQ210V6开发板