移植uboot1.3.1到s3c2410（5）--nandflash支持

2.1        在/board/Embest/edukit2410/edukit2410.c文件的末尾添加对Nand Flash 的初始化函数（在后面Nand Flash的操作都要用到）

u-boot运行至第二阶段进入start_armboot()函数。其中nand_init()函数是对nand flash的最初初始化函数。Nand_init()函数在两个文件中实现。其调用与CFG_NAND_LEGACY宏有关，如果没有定义这个宏，系统调用 drivers/nand/nand.c中的nand_init()；否则调用自己在board/Embest/edukit2410/edukit2410.c中的nand_init()函数。这里我选择第二种方式。

#if defined(CONFIG_CMD_NAND)

typedef enum {

    NFCE_LOW,

    NFCE_HIGH

} NFCE_STATE;

 

static inline void NF_Conf(u16 conf)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    nand->NFCONF = conf;

}

 

 

static inline void NF_Cmd(u8 cmd)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    nand->NFCMD = cmd;

}

 

static inline void NF_CmdW(u8 cmd)

{

    NF_Cmd(cmd);

    udelay(1);

}

 

static inline void NF_Addr(u8 addr)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    nand->NFADDR = addr;

}

 

 

static inline void NF_WaitRB(void)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    while (!(nand->NFSTAT & (1<<0)));

}

 

static inline void NF_Write(u8 data)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    nand->NFDATA = data;

}

 

static inline u8 NF_Read(void)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    return(nand->NFDATA);

}

 

static inline u32 NF_Read_ECC(void)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    return(nand->NFECC);

}

 

static inline void NF_SetCE(NFCE_STATE s)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    switch (s) {

    case NFCE_LOW:

        nand->NFCONF &= ~(1<<11);

        break;

    case NFCE_HIGH:

        nand->NFCONF |= (1<<11);

        break;

    }

}

 

static inline void NF_Init_ECC(void)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

    nand->NFCONF |= (1<<12);

}

 

extern ulong nand_probe(ulong physadr);

 

static inline void NF_Reset(void)

{

    int i;

 

    NF_SetCE(NFCE_LOW);

    NF_Cmd(0xFF);        /* reset command */

    for(i = 0; i < 10; i++);    /* tWB = 100ns. */

    NF_WaitRB();        /* wait 200~500us; */

    NF_SetCE(NFCE_HIGH);

}

 

static inline void NF_Init(void)

{

#if 0

#define TACLS 0

#define TWRPH0 3

#define TWRPH1 0

#else

#define TACLS 0

#define TWRPH0 4

#define TWRPH1 2

#endif

 

#if defined(CONFIG_S3C2440)

    NF_Conf((TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4));

    NF_Cont((1<<6)|(1<<4)|(1<<1)|(1<<0));

#else

    NF_Conf((1<<15)|(0<<14)|(0<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0));

    /*nand->NFCONF = (1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0); */

    /* 1 1 1 1, 1 xxx, r xxx, r xxx */

    /* En 512B 4step ECCR nFCE=H tACLS tWRPH0 tWRPH1 */

#endif

    NF_Reset();

}

 

void nand_init(void)

{

    S3C2410_NAND * const nand = S3C2410_GetBase_NAND();

 

    NF_Init();

#ifdef DEBUG

    printf("NAND flash probing at 0x%.8lX\n", (ulong)nand);

#endif

    printf ("%4lu MB\n", nand_probe((ulong)nand) >> 20);

}

#endif