u-boot/board/prodrive/alpr/nand.c

/*
 * (C) Copyright 2006
 * Heiko Schocher, DENX Software Engineering, hs@denx.de
 *
 * (C) Copyright 2006
 * Stefan Roese, DENX Software Engineering, sr@denx.de.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>

#if defined(CONFIG_CMD_NAND)

#include <asm/processor.h>
#include <nand.h>

struct alpr_ndfc_regs {
	u8 cmd[4];
	u8 addr_wait;
	u8 term;
	u8 dummy;
	u8 dummy2;
	u8 data;
};

static u8 hwctl;
static struct alpr_ndfc_regs *alpr_ndfc = NULL;

#define readb(addr)	(u8)(*(volatile u8 *)(addr))
#define writeb(d,addr)	*(volatile u8 *)(addr) = ((u8)(d))

/*
 * The ALPR has a NAND Flash Controller (NDFC) that handles all accesses to
 * the NAND devices.  The NDFC has command, address and data registers that
 * when accessed will set up the NAND flash pins appropriately.  We'll use the
 * hwcontrol function to save the configuration in a global variable.
 * We can then use this information in the read and write functions to
 * determine which NDFC register to access.
 *
 * There are 2 NAND devices on the board, a Hynix HY27US08561A (1 GByte).
 */
static void alpr_nand_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
	struct nand_chip *this = mtd->priv;

	if (ctrl & NAND_CTRL_CHANGE) {
		if ( ctrl & NAND_CLE )
			hwctl |= 0x1;
		else
			hwctl &= ~0x1;
		if ( ctrl & NAND_ALE )
			hwctl |= 0x2;
		else
			hwctl &= ~0x2;
		if ( (ctrl & NAND_NCE) != NAND_NCE)
			writeb(0x00, &(alpr_ndfc->term));
	}
	if (cmd != NAND_CMD_NONE)
		writeb(cmd, this->IO_ADDR_W);
}

static u_char alpr_nand_read_byte(struct mtd_info *mtd)
{
	return readb(&(alpr_ndfc->data));
}

static void alpr_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
{
	struct nand_chip *nand = mtd->priv;
	int i;

	for (i = 0; i < len; i++) {
		if (hwctl & 0x1)
			 /*
			  * IO_ADDR_W used as CMD[i] reg to support multiple NAND
			  * chips.
			  */
			writeb(buf[i], nand->IO_ADDR_W);
		else if (hwctl & 0x2)
			writeb(buf[i], &(alpr_ndfc->addr_wait));
		else
			writeb(buf[i], &(alpr_ndfc->data));
	}
}

static void alpr_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
	int i;

	for (i = 0; i < len; i++) {
		buf[i] = readb(&(alpr_ndfc->data));
	}
}

static int alpr_nand_dev_ready(struct mtd_info *mtd)
{
	/*
	 * Blocking read to wait for NAND to be ready
	 */
	(void)readb(&(alpr_ndfc->addr_wait));

	/*
	 * Return always true
	 */
	return 1;
}

int board_nand_init(struct nand_chip *nand)
{
	alpr_ndfc = (struct alpr_ndfc_regs *)CONFIG_SYS_NAND_BASE;

	nand->ecc.mode = NAND_ECC_SOFT;

	/* Reference hardware control function */
	nand->cmd_ctrl  = alpr_nand_hwcontrol;
	nand->read_byte  = alpr_nand_read_byte;
	nand->write_buf  = alpr_nand_write_buf;
	nand->read_buf   = alpr_nand_read_buf;
	nand->dev_ready  = alpr_nand_dev_ready;

	return 0;
}
#endif