u-boot2011.03支持s3c2440，寄存器在arch/arm/includer/asm/目錄下s3c24x0_cpu.h中定義。
代碼中包含了s3c2410讀寫nandflash函數，因此在s3c2410基礎上進行修改
U-Boot源代碼下載地址 http://www.linuxidc.com/Linux/2011-07/38897.htm
建一個s3c2440_nand.c文件
cd drivers/mtd/nand/
cp s3c2410_nand.c s3c2440_nand.c
代碼如下
寄存器操作說明：
readl函數原型
#define readl(addr) (*(volatile unsigned int*)(addr))
writeb函數原型
#define writel(b,addr) ((*(volatile unsigned int *) (addr)) = (b))
#include <common.h>
#include <nand.h>
#include <asm/arch/s3c24x0_cpu.h>
#include <asm/io.h>
#define S3C2440_NFCONT_EN (1<<0)
#define S3C2440_NFCONT_nFCE (0<<1)
#define S3C2440_NFCONT_INITECC (1<<4)
#define S3C2440_NFCONF_TACLS(x) ((x)<<12)
#define S3C2440_NFCONF_TWRPH0(x) ((x)<<8)
#define S3C2440_NFCONF_TWRPH1(x) ((x)<<4)
#define S3C2440_ADDR_NALE 0x0c
#define S3C2440_ADDR_NCLE 0x08
#ifdef CONFIG_NAND_SPL
/* in the early stage of NAND flash booting, printf() is not available */
#define printf(fmt, args...)
static void nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
int i;
struct nand_chip *this = mtd->priv;
for (i = 0; i < len; i++)
buf[i] = readb(this->IO_ADDR_R);
}
#endif
static void s3c2440_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
struct nand_chip *chip = mtd->priv;
struct s3c2440_nand *nand = s3c2440_get_base_nand();
debugX(1, "hwcontrol(): 0x%02x 0x%02x\n", cmd, ctrl);
if (ctrl & NAND_CTRL_CHANGE) {
ulong IO_ADDR_W = (ulong)nand;
if (!(ctrl & NAND_CLE))
IO_ADDR_W |= S3C2440_ADDR_NALE;
if (!(ctrl & NAND_ALE))
IO_ADDR_W |= S3C2440_ADDR_NCLE;//特別注意修改
chip->IO_ADDR_W = (void *)IO_ADDR_W;
if (ctrl & NAND_NCE)
writel(readl(&nand->nfcont) & (~(1<<1)),
&nand->nfcont);
else
writel(readl(&nand->nfcont) | (1<<1),
&nand->nfcont);
}
if (cmd != NAND_CMD_NONE)
writeb(cmd, chip->IO_ADDR_W);
}
static int s3c2440_dev_ready(struct mtd_info *mtd)
{
struct s3c2440_nand *nand = s3c2440_get_base_nand();
debugX(1, "dev_ready\n");
return readl(&nand->nfstat) & 0x01;
}
#ifdef CONFIG_S3C2440_NAND_HWECC
void s3c2440_nand_enable_hwecc(struct mtd_info *mtd, int mode)
{
struct s3c2440_nand *nand = s3c2440_get_base_nand();
debugX(1, "s3c2440_nand_enable_hwecc(%p, %d)\n", mtd, mode);
writel(readl(&nand->nfconf) | S3C2440_NFCONF_INITECC, &nand->nfconf);
}
static int s3c2440_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code)
{
struct s3c2440_nand *nand = s3c2440_get_base_nand();
ecc_code[0] = readb(&nand->nfecc);
ecc_code[1] = readb(&nand->nfecc + 1);
ecc_code[2] = readb(&nand->nfecc + 2);
debugX(1, "s3c2440_nand_calculate_hwecc(%p,): 0x%02x 0x%02x 0x%02x\n",
mtd , ecc_code[0], ecc_code[1], ecc_code[2]);
return 0;
}
static int s3c2440_nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc)
{
if (read_ecc[0] == calc_ecc[0] &&
read_ecc[1] == calc_ecc[1] &&
read_ecc[2] == calc_ecc[2])
return 0;
printf("s3c2440_nand_correct_data: not implemented\n");
return -1;
}
#endif
int board_nand_init(struct nand_chip *nand)
{
u_int32_t cfg;
u_int8_t tacls, twrph0, twrph1;
struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
struct s3c2440_nand *nand_reg = s3c2440_get_base_nand();
debugX(1, "board_nand_init()\n");
writel(readl(&clk_power->clkcon) | (1 << 4), &clk_power->clkcon);
/* initialize hardware */
#if defined(CONFIG_S3C24XX_CUSTOM_NAND_TIMING)
tacls = CONFIG_S3C24XX_TACLS;
twrph0 = CONFIG_S3C24XX_TWRPH0;
twrph1 = CONFIG_S3C24XX_TWRPH1;
#else
tacls = 4;
twrph0 = 8;
twrph1 = 8;
#endif
cfg = S3C2440_NFCONF_TACLS(tacls - 1);
cfg |= S3C2440_NFCONF_TWRPH0(twrph0 - 1);
cfg |= S3C2440_NFCONF_TWRPH1(twrph1 - 1);
writel(cfg, &nand_reg->nfconf);
cfg = S3C2440_NFCONT_EN;
cfg |= S3C2440_NFCONT_nFCE;
cfg |= S3C2440_NFCONT_INITECC；
writel(cfg, &nand_reg->nfcont);
/* initialize nand_chip data structure */
nand->IO_ADDR_R = (void *)&nand_reg->nfdata;
nand->IO_ADDR_W = (void *)&nand_reg->nfdata;
nand->select_chip = NULL;
/* read_buf and write_buf are default */
/* read_byte and write_byte are default */
#ifdef CONFIG_NAND_SPL
nand->read_buf = nand_read_buf;
#endif
/* hwcontrol always must be implemented */
nand->cmd_ctrl = s3c2440_hwcontrol;
nand->dev_ready = s3c2440_dev_ready;
#ifdef CONFIG_S3C2440_NAND_HWECC
nand->ecc.hwctl = s3c2440_nand_enable_hwecc;
nand->ecc.calculate = s3c2440_nand_calculate_ecc;
nand->ecc.correct = s3c2440_nand_correct_data;
nand->ecc.mode = NAND_ECC_HW;
nand->ecc.size = CONFIG_SYS_NAND_ECCSIZE;
nand->ecc.bytes = CONFIG_SYS_NAND_ECCBYTES;
#else
nand->ecc.mode = NAND_ECC_SOFT;
#endif
#ifdef CONFIG_S3C2440_NAND_BBT
nand->options = NAND_USE_FLASH_BBT;
#else
nand->options = 0;
#endif
debugX(1, "end of nand_init\n");
return 0;
}
再在include/configs/mini2440.h中添加
#define CONFIG_NAND_S3C2440
#define CONFIG_SYS_MAX_NAND_DEVICE 1
#define CONFIG_SYS_NAND_BASE 0x4E000000
#define CONFIG_MTD_DEVICE
#define CONFIG_CMD_NAND
編譯好後使用supervivi 的d命令下載到sdram的0x33f80000地指出執行
U-Boot 2011.03 (Nov 29 2011 - 09:21:34)
DRAM: 64 MiB
Flash: 2 MiB
NAND: 256 MiB
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Net: dm9000
mini2440 # nand info
Device 0: nand0, sector size 128 KiB
mini2440 #
mini2440已經能夠很好的支持nand flash