uboot之nand flash相关(1)

这几天在做和nandflash相关的东西，之前uboot中nandflash部分搞得模模糊糊。这次就将uboot中nand flash相关部分分析清楚

。本文uboot版本1.3.3

按照uboot的执行流程，在lib_arm/board.c文件中的start_armboot函数中会调用到nand初始化。

初始化的调用流程大致为：

start_armboot

nand_init //driver/mtd/nand/nand.c

nand_init_chip //driver/mtd/nand/nand.c

board_nand_init //cpu/sep4020/nand_flash.c

nand_scan //driver/mtd/nand/nand_base.c

start_armboot函数中，nand初始化部分

#if defined(CONFIG_CMD_NAND)    /*有nand的板都会定义CONFIG_CMD_NAND*/
    puts ("NAND:  ");
    nand_init();        /* go init the NAND */
#endif

nand_init()在driver/mtd/nand/nand.c文件中定义,此为nand初始化入口函数。

void nand_init(void)
{
    int i;
    unsigned int size = 0;
    for (i = 0; i < CFG_MAX_NAND_DEVICE; i++) {    //(1)
        nand_init_chip(&nand_info[i], &nand_chip[i], base_address[i]);    //(2)
        size += nand_info[i].size;    //(3)
        if (nand_curr_device == -1)
            nand_curr_device = i;
    }
    printf("%lu MiB\n", size / (1024 * 1024));

#ifdef CFG_NAND_SELECT_DEVICE
    /*
     * Select the chip in the board/cpu specific driver
     */
    board_nand_select_device(nand_info[nand_curr_device].priv, nand_curr_device);
#endif
}

(1)CFG_MAX_NAND_DEVICE，nand的数量，一般板上有一个nand，就定义为1

(2)此函数初始化一个nand flash。首先看函数参数的3个变量。

  参数1 nand_info[i],其定义如

nand_info_t nand_info[CFG_MAX_NAND_DEVICE]; //driver/mtd/nand/nand.c

   定义了一个nand_info_t类型的全局数组，当然这里其CFG_MAX_NAND_DEVICE等于1，只有一个成员，再看nand_info_t定义

typedef struct mtd_info nand_info_t; //include/Nand.h

   mtd_info定义在include/linux/mtd/mtd.h中，它表示一个mtd设备的结构体，包含了mtd属性和其操作函数。

struct mtd_info {
        u_char type;
        u_int32_t flags;
        u_int32_t size;     /* Total size of the MTD */

        /* "Major" erase size for the device. Na飗e users may take this
         * to be the only erase size available, or may use the more detailed
         * information below if they desire
         */
        u_int32_t erasesize;

        u_int32_t oobblock;  /* Size of OOB blocks (e.g. 512) */
        u_int32_t oobsize;   /* Amount of OOB data per block (e.g. 16) */
        u_int32_t oobavail;  /* Number of bytes in OOB area available for fs  */
        u_int32_t ecctype;
        u_int32_t eccsize;


        /* Kernel-only stuff starts here. */
        char *name;
        int index;

        /* oobinfo is a nand_oobinfo structure, which can be set by iotcl (MEMSETOOBINFO) */
        struct nand_oobinfo oobinfo;

        /* Data for variable erase regions. If numeraseregions is zero,
         * it means that the whole device has erasesize as given above.
         */
        int numeraseregions;
        struct mtd_erase_region_info *eraseregions;

        /* This really shouldn't be here. It can go away in 2.5 */
        u_int32_t bank_size;

        int (*erase) (struct mtd_info *mtd, struct erase_info *instr);

        /* This stuff for eXecute-In-Place */
        int (*point) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf);

        /* We probably shouldn't allow XIP if the unpoint isn't a NULL */
        void (*unpoint) (struct mtd_info *mtd, u_char * addr, loff_t from, size_t len);


        int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
        int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);

        int (*read_ecc) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf, u_char

    *eccbuf, struct nand_oobinfo *oobsel);
        int (*write_ecc) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf, u_char

    *eccbuf, struct nand_oobinfo *oobsel);

        int (*read_oob) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
        int (*write_oob) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);

        /*
         * Methods to access the protection register area, present in some
         * flash devices. The user data is one time programmable but the
         * factory data is read only.
         */
        int (*read_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);

        int (*read_fact_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);

        /* This function is not yet implemented */
        int (*write_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);

        /* Sync */
        void (*sync) (struct mtd_info *mtd);

        /* Bad block management functions */
        int (*block_isbad) (struct mtd_info *mtd, loff_t ofs);
        int (*block_markbad) (struct mtd_info *mtd, loff_t ofs);

        void *priv;

        struct module *owner;
        int usecount;
    };

   参数2 nand_chip[i] ，如下

   static struct nand_chip nand_chip[CFG_MAX_NAND_DEVICE];

   再看struct nand_chip定义，当前文件（driver/mtd/nand/nand.c）包含nand.h(include目录)，nand.h又包含#include ，所以nand_chip的定义是linux/mtd/nand.h中的。不是nand_legacy.h。这个结构体表示一个nand flash其包含所有属性和操作函数。

/**
 * struct nand_chip - NAND Private Flash Chip Data
 * @IO_ADDR_R:        [BOARDSPECIFIC] address to read the 8 I/O lines of the flash device
 * @IO_ADDR_W:        [BOARDSPECIFIC] address to write the 8 I/O lines of the flash device
 * @read_byte:        [REPLACEABLE] read one byte from the chip
 * @write_byte:        [REPLACEABLE] write one byte to the chip
 * @read_word:        [REPLACEABLE] read one word from the chip
 * @write_word:        [REPLACEABLE] write one word to the chip
 * @write_buf:        [REPLACEABLE] write data from the buffer to the chip
 * @read_buf:        [REPLACEABLE] read data from the chip into the buffer
 * @verify_buf:        [REPLACEABLE] verify buffer contents against the chip data
 * @select_chip:    [REPLACEABLE] select chip nr
 * @block_bad:        [REPLACEABLE] check, if the block is bad
 * @block_markbad:    [REPLACEABLE] mark the block bad
 * @hwcontrol:        [BOARDSPECIFIC] hardwarespecific function for accesing control-lines
 * @dev_ready:        [BOARDSPECIFIC] hardwarespecific function for accesing device ready/busy line
 *            If set to NULL no access to ready/busy is available and the ready/busy information
 *            is read from the chip status register
 * @cmdfunc:        [REPLACEABLE] hardwarespecific function for writing commands to the chip
 * @waitfunc:        [REPLACEABLE] hardwarespecific function for wait on ready
 * @calculate_ecc:    [REPLACEABLE] function for ecc calculation or readback from ecc hardware
 * @correct_data:    [REPLACEABLE] function for ecc correction, matching to ecc generator (sw/hw)
 * @enable_hwecc:    [BOARDSPECIFIC] function to enable (reset) hardware ecc generator. Must only
 *            be provided if a hardware ECC is available
 * @erase_cmd:        [INTERN] erase command write function, selectable due to AND support
 * @scan_bbt:        [REPLACEABLE] function to scan bad block table
 * @eccmode:        [BOARDSPECIFIC] mode of ecc, see defines
 * @eccsize:        [INTERN] databytes used per ecc-calculation
 * @eccbytes:        [INTERN] number of ecc bytes per ecc-calculation step
 * @eccsteps:        [INTERN] number of ecc calculation steps per page
 * @chip_delay:        [BOARDSPECIFIC] chip dependent delay for transfering data from array to read regs (tR)
 * @chip_lock:        [INTERN] spinlock used to protect access to this structure and the chip
 * @wq:            [INTERN] wait queue to sleep on if a NAND operation is in progress
 * @state:        [INTERN] the current state of the NAND device
 * @page_shift:        [INTERN] number of address bits in a page (column address bits)
 * @phys_erase_shift:    [INTERN] number of address bits in a physical eraseblock
 * @bbt_erase_shift:    [INTERN] number of address bits in a bbt entry
 * @chip_shift:        [INTERN] number of address bits in one chip
 * @data_buf:        [INTERN] internal buffer for one page + oob
 * @oob_buf:        [INTERN] oob buffer for one eraseblock
 * @oobdirty:        [INTERN] indicates that oob_buf must be reinitialized
 * @data_poi:        [INTERN] pointer to a data buffer
 * @options:        [BOARDSPECIFIC] various chip options. They can partly be set to inform nand_scan about
 *            special functionality. See the defines for further explanation
 * @badblockpos:    [INTERN] position of the bad block marker in the oob area
 * @numchips:        [INTERN] number of physical chips
 * @chipsize:        [INTERN] the size of one chip for multichip arrays
 * @pagemask:        [INTERN] page number mask = number of (pages / chip) - 1
 * @pagebuf:        [INTERN] holds the pagenumber which is currently in data_buf
 * @autooob:        [REPLACEABLE] the default (auto)placement scheme
 * @bbt:        [INTERN] bad block table pointer
 * @bbt_td:        [REPLACEABLE] bad block table descriptor for flash lookup
 * @bbt_md:        [REPLACEABLE] bad block table mirror descriptor
 * @badblock_pattern:    [REPLACEABLE] bad block scan pattern used for initial bad block scan
 * @controller:        [OPTIONAL] a pointer to a hardware controller structure which is shared among multiple independend devices
 * @priv:        [OPTIONAL] pointer to private chip date
 */

struct nand_chip {
    void  __iomem    *IO_ADDR_R;
    void  __iomem    *IO_ADDR_W;

    u_char        (*read_byte)(struct mtd_info *mtd);
    void        (*write_byte)(struct mtd_info *mtd, u_char byte);
    u16        (*read_word)(struct mtd_info *mtd);
    void        (*write_word)(struct mtd_info *mtd, u16 word);

    void        (*write_buf)(struct mtd_info *mtd, const u_char *buf, int len);
    void        (*read_buf)(struct mtd_info *mtd, u_char *buf, int len);
    int        (*verify_buf)(struct mtd_info *mtd, const u_char *buf, int len);
    void        (*select_chip)(struct mtd_info *mtd, int chip);
    int        (*block_bad)(struct mtd_info *mtd, loff_t ofs, int getchip);
    int        (*block_markbad)(struct mtd_info *mtd, loff_t ofs);
    void        (*hwcontrol)(struct mtd_info *mtd, int cmd);
    int        (*dev_ready)(struct mtd_info *mtd);
    void        (*cmdfunc)(struct mtd_info *mtd, unsigned command, int column, int page_addr);
    int        (*waitfunc)(struct mtd_info *mtd, struct nand_chip *this, int state);
    int        (*calculate_ecc)(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code);
    int        (*correct_data)(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc);
    void        (*enable_hwecc)(struct mtd_info *mtd, int mode);
    void        (*erase_cmd)(struct mtd_info *mtd, int page);
    int        (*scan_bbt)(struct mtd_info *mtd);
    int        eccmode;
    int        eccsize;
    int        eccbytes;
    int        eccsteps;
    int        chip_delay;
#if 0
    spinlock_t    chip_lock;
    wait_queue_head_t wq;
    nand_state_t    state;
#endif
    int        page_shift;
    int        phys_erase_shift;
    int        bbt_erase_shift;
    int        chip_shift;
    u_char        *data_buf;
    u_char        *oob_buf;
    int        oobdirty;
    u_char        *data_poi;
    unsigned int    options;
    int        badblockpos;
    int        numchips;
    unsigned long    chipsize;
    int        pagemask;
    int        pagebuf;
    struct nand_oobinfo    *autooob;
    uint8_t        *bbt;
    struct nand_bbt_descr    *bbt_td;
    struct nand_bbt_descr    *bbt_md;
    struct nand_bbt_descr    *badblock_pattern;
    struct nand_hw_control    *controller;
    void        *priv;
};

  参数3 base_address[i]，如下

  static ulong base_address[CFG_MAX_NAND_DEVICE] = CFG_NAND_BASE_LIST;

  CFG_NAND_BASE_LIST如下，

  #ifndef CFG_NAND_BASE_LIST

#define CFG_NAND_BASE_LIST { CFG_NAND_BASE }

  #endif

  CFG_NAND_BASE是在include/configs/UB4020.h中配置为

  #define CFG_NAND_BASE 0x11000200 （nand FIFO 数据寄存器）

  

  (3)计算出总共nandflash多少容量，在紧随其后的printf语句中打印出来。

  

  接着看同文件（driver/mtd/nand/nand.c）中nand_init_chip函数的分析

static void nand_init_chip(struct mtd_info *mtd, struct nand_chip *nand, ulong base_addr)
{
    mtd->priv = nand;

    nand->IO_ADDR_R = nand->IO_ADDR_W = (void  __iomem *)base_addr;    //(1)
    if (board_nand_init(nand) == 0) {            //(2)
        if (nand_scan(mtd, 1) == 0) {            //(3)
            if (!mtd->name)    //这个名字在nand_scan中设置，如果在table中找到就有了。
                mtd->name = (char *)default_nand_name;
        } else
            mtd->name = NULL;
    } else {
        mtd->name = NULL;
        mtd->size = 0;
    }

}

(1)从上面的nand_chip结构体中写道IO_ADDR_R，IO_ADDR_W是nand flash的读写地址， base_add这里设置为0x11000200，正好的nand FIFO的数据寄存器，读写flash的接口寄存器。

(2)此函数设置相关的nand 初始化，它和具体的体现结构有关系，不是共性的东西，在cpu/xxx/Nand_flash.c文件中。

(3) 此函数设置通用默认处理，获得flash id，并匹配等等。

  

这里我们分析的是sep4020 cpu的board_nand_init() 在cpu/sep4020/nand_flash.c

int board_nand_init( struct nand_chip *chip )
 {
    memset((char *) chip, 0, sizeof(struct nand_chip));

    INTC_IMR = 0XFFFFFFFF;    //(REGW(INTC_BASE+0X008))IRQ中断屏蔽寄存器 置1为屏蔽 0为通过
    INTC_IMR = 0X00000000;

    EMI_NAND_CONF1 = 0x06402857;    //(1)
    EMI_NAND_CONF2 = 0x00d14353;    //(2)

    vaddr = malloc(2112);            //(3)
    oob64 = malloc(2112);
    memset(vaddr,0,2112);
    memset(oob64,0,2112);

    int erasepage;
    /*设置nand_chip结构中的各个函数指针*/
    /* Set address of NAND IO lines */
    chip->IO_ADDR_R = (void *) EMI_NAND_DATA_RAW;    //设置nand flash读写寄存器地址，其实在调用函数中已经设置过了
    chip->IO_ADDR_W = (void *) EMI_NAND_DATA_RAW;
    /* Set address of hardware control function */
    chip->hwcontrol = sep4020_hwcontrol;
    /* 15 us command delay time */
    chip->dev_ready = sep4020_nand_dev_ready;
    chip->chip_delay = 15;
    chip->write_buf    = sep4020_nand_write_buf;
    chip->read_buf  = sep4020_nand_read_buf;
    chip->write_byte = sep4020_nand_write_byte;
    chip->read_byte =  sep4020_nand_read_byte;
    chip->eccmode = NAND_ECC_SOFT;
    chip->select_chip = sep4020_nand_select_chip;

    chip->cmdfunc = sep4020_nand_command;
    chip->erase_cmd = sep4020_nand_cmd_erase;
    /* Return happy */
    return 0;
 }

(1)NAND FLASH的配置器存器1 110-0--100--000000--101000--0101--0111 可查看芯片手册，其中一项设置成5级地址

(2)NAND FLASH的配置器存器2  1--1--0--100--010100--0011--01--01--00--11 可查看芯片手册，页大小配置为2K

(3)分配一个整页空间，后续的读写操作中会用到它来暂存一页数据。