nand.c

讲述LPC2468在无操作系统条件下使用YAFFS文件系统是如何实现的以及完整的测试代码,代码部分详见lpc2468_yaffs2.rar

#include <common.h>
#include <nand.h>

/*
 * CLE at A20
 * ALE at A19
 */
#define MASK_CLE (1l<<21)
#define MASK_ALE (1l<<22)

static void lpc24xx_nand_hwcontrol(struct mtd_info *mtd,
					 int cmd, unsigned int ctrl)
{
	struct nand_chip *this = mtd->priv;
	if (ctrl & NAND_CTRL_CHANGE) {
		ulong IO_ADDR_W = (ulong) this->IO_ADDR_W;
		IO_ADDR_W &= ~(MASK_ALE | MASK_CLE);

		if (ctrl & NAND_CLE)
			IO_ADDR_W |= MASK_CLE;
		if (ctrl & NAND_ALE)
			IO_ADDR_W |= MASK_ALE;
			
		

	//((AT91PS_PIO) AT91C_BASE_PIOC)->PIO_OER = !(ctrl & NAND_NCE);
//		set_gpio_value(AT91_PIN_PC15, !(ctrl & NAND_NCE));
		this->IO_ADDR_W = (void *) IO_ADDR_W;
	}

	if (cmd != NAND_CMD_NONE)
		writeb(cmd, this->IO_ADDR_W);

//	printf("%s, 0x%02x, 0x%02x, addr = 0x%08x\n", __FUNCTION__, (uint8_t)cmd, ctrl, this->IO_ADDR_W);
}

static int lpc24xx_nand_ready(struct mtd_info *mtd)
{
	//returun *AT91C_PIOC_PDSR & AT91_PIN_PC13;
//	return at91_get_gpio_value(AT91_PIN_PC14);
	return nand_ready_lowlevel();
}

int board_nand_init(struct nand_chip *nand)
{
	nand->ecc.mode = NAND_ECC_SOFT;
#ifdef CFG_NAND_DBW_16
	nand->options = NAND_BUSWIDTH_16;
#endif
	nand->cmd_ctrl = lpc24xx_nand_hwcontrol;
	nand->dev_ready = lpc24xx_nand_ready;
	nand->chip_delay = 20;

	return 0;
}