/*
 *  arch/cris/arch-v32/drivers/nandflash.c
 *
 *  Copyright (c) 2004
 *
 *  Derived from drivers/mtd/nand/spia.c
 *	  Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <arch/memmap.h>
#include <hwregs/reg_map.h>
#include <hwregs/reg_rdwr.h>
#include <hwregs/gio_defs.h>
#include <hwregs/bif_core_defs.h>
#include <asm/io.h>

#define CE_BIT 4
#define CLE_BIT 5
#define ALE_BIT 6
#define BY_BIT 7

struct mtd_info_wrapper {
	struct nand_chip chip;
};

/* Bitmask for control pins */
#define PIN_BITMASK ((1 << CE_BIT) | (1 << CLE_BIT) | (1 << ALE_BIT))

/* Bitmask for mtd nand control bits */
#define CTRL_BITMASK (NAND_NCE | NAND_CLE | NAND_ALE)


static struct mtd_info *crisv32_mtd;
/*
 *	hardware specific access to control-lines
 */
static void crisv32_hwcontrol(struct mtd_info *mtd, int cmd,
			      unsigned int ctrl)
{
	unsigned long flags;
	reg_gio_rw_pa_dout dout;
	struct nand_chip *this = mtd_to_nand(mtd);

	local_irq_save(flags);

	/* control bits change */
	if (ctrl & NAND_CTRL_CHANGE) {
		dout = REG_RD(gio, regi_gio, rw_pa_dout);
		dout.data &= ~PIN_BITMASK;

#if (CE_BIT == 4 && NAND_NCE == 1 &&  \
     CLE_BIT == 5 && NAND_CLE == 2 && \
     ALE_BIT == 6 && NAND_ALE == 4)
		/* Pins in same order as control bits, but shifted.
		 * Optimize for this case; works for 2.6.18 */
		dout.data |= ((ctrl & CTRL_BITMASK) ^ NAND_NCE) << CE_BIT;
#else
		/* the slow way */
		if (!(ctrl & NAND_NCE))
			dout.data |= (1 << CE_BIT);
		if (ctrl & NAND_CLE)
			dout.data |= (1 << CLE_BIT);
		if (ctrl & NAND_ALE)
			dout.data |= (1 << ALE_BIT);
#endif
		REG_WR(gio, regi_gio, rw_pa_dout, dout);
	}

	/* command to chip */
	if (cmd != NAND_CMD_NONE)
		writeb(cmd, this->IO_ADDR_W);

	local_irq_restore(flags);
}

/*
*	read device ready pin
*/
static int crisv32_device_ready(struct mtd_info *mtd)
{
	reg_gio_r_pa_din din = REG_RD(gio, regi_gio, r_pa_din);
	return ((din.data & (1 << BY_BIT)) >> BY_BIT);
}

/*
 * Main initialization routine
 */
struct mtd_info *__init crisv32_nand_flash_probe(void)
{
	void __iomem *read_cs;
	void __iomem *write_cs;

	reg_bif_core_rw_grp3_cfg bif_cfg = REG_RD(bif_core, regi_bif_core,
		rw_grp3_cfg);
	reg_gio_rw_pa_oe pa_oe = REG_RD(gio, regi_gio, rw_pa_oe);
	struct mtd_info_wrapper *wrapper;
	struct nand_chip *this;
	int err = 0;

	/* Allocate memory for MTD device structure and private data */
	wrapper = kzalloc(sizeof(struct mtd_info_wrapper), GFP_KERNEL);
	if (!wrapper) {
		printk(KERN_ERR "Unable to allocate CRISv32 NAND MTD "
			"device structure.\n");
		err = -ENOMEM;
		return NULL;
	}

	read_cs = ioremap(MEM_CSP0_START | MEM_NON_CACHEABLE, 8192);
	write_cs = ioremap(MEM_CSP1_START | MEM_NON_CACHEABLE, 8192);

	if (!read_cs || !write_cs) {
		printk(KERN_ERR "CRISv32 NAND ioremap failed\n");
		err = -EIO;
		goto out_mtd;
	}

	/* Get pointer to private data */
	this = &wrapper->chip;
	crisv32_mtd = nand_to_mtd(this);

	pa_oe.oe |= 1 << CE_BIT;
	pa_oe.oe |= 1 << ALE_BIT;
	pa_oe.oe |= 1 << CLE_BIT;
	pa_oe.oe &= ~(1 << BY_BIT);
	REG_WR(gio, regi_gio, rw_pa_oe, pa_oe);

	bif_cfg.gated_csp0 = regk_bif_core_rd;
	bif_cfg.gated_csp1 = regk_bif_core_wr;
	REG_WR(bif_core, regi_bif_core, rw_grp3_cfg, bif_cfg);

	/* Set address of NAND IO lines */
	this->IO_ADDR_R = read_cs;
	this->IO_ADDR_W = write_cs;
	this->cmd_ctrl = crisv32_hwcontrol;
	this->dev_ready = crisv32_device_ready;
	/* 20 us command delay time */
	this->chip_delay = 20;
	this->ecc.mode = NAND_ECC_SOFT;
	this->ecc.algo = NAND_ECC_HAMMING;

	/* Enable the following for a flash based bad block table */
	/* this->bbt_options = NAND_BBT_USE_FLASH; */

	/* Scan to find existence of the device */
	if (nand_scan(crisv32_mtd, 1)) {
		err = -ENXIO;
		goto out_ior;
	}

	return crisv32_mtd;

out_ior:
	iounmap((void *)read_cs);
	iounmap((void *)write_cs);
out_mtd:
	kfree(wrapper);
	return NULL;
}