大家好，又到了天嵌【嵌入式分享】的時間，相對于前幾期【嵌入式分享】做的主要是TQ335X開發(fā)板的技術分享，本期決定做同是cortex-a8系列的TQ210開發(fā)板的技術分享。本期是關于TQ210開發(fā)板的Nand flash驅動編寫，可能源碼部分會比較多，本文由博主girlkoo編寫，感謝他的分享。
跟裸機程序一樣，S5PV210(TQ210)的Nand flash模塊跟S3C2440(TQ2440)的Nand flash模塊非常相似，如果不引入ECC，驅動程序的編寫也非常簡單，我是使用的Linux-3.8.6(Linux-3.8.3也一樣)內核，驅動的API函數(shù)有些變化，不過原理是相通的，稍微看一下內核源碼并參考下其他平臺的相關代碼就可以自己寫出Nand flash驅動了，下面是Nand flash驅動的源碼，沒有啟用ECC，當然，你也可以改成軟件ECC，但是我的覺得既然軟件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;
//分配驅動相關結構體
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;
}
//設置驅動相關結構體
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;
//掃描Nand flash 設備
if(nand_scan(s5p_mtd_info, 1)){
dev_dbg(&pdev->dev, "nand scan error\n");
goto err_free_info;
}
//添加分區(qū)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");
上述源碼為嵌入式愛好者分享，如有更新，請咨詢相關客服與銷售人員，以便更新與開發(fā)。
操作所使用的硬件：
TQ210V6開發(fā)板
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