nandflash.c

/*
 *  arch/cris/arch-v32/drivers/nandflash.c
 *
 *  Copyright (c) 2007
 *
 *  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/rawnand.h>
#include <linux/mtd/partitions.h>
#include <arch/memmap.h>
#include <hwregs/reg_map.h>
#include <hwregs/reg_rdwr.h>
#include <hwregs/pio_defs.h>
#include <pinmux.h>
#include <asm/io.h>

#define MANUAL_ALE_CLE_CONTROL 1

#define regf_ALE	a0
#define regf_CLE	a1
#define regf_NCE	ce0_n

#define CLE_BIT 10
#define ALE_BIT 11
#define CE_BIT 12

struct mtd_info_wrapper {
	struct nand_chip chip;
};

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

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_pio_rw_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(pio, regi_pio, rw_dout);
		dout.regf_NCE = (ctrl & NAND_NCE) ? 0 : 1;

#if !MANUAL_ALE_CLE_CONTROL
		if (ctrl & NAND_ALE) {
			/* A0 = ALE high */
			this->IO_ADDR_W = (void __iomem *)REG_ADDR(pio,
				regi_pio, rw_io_access1);
		} else if (ctrl & NAND_CLE) {
			/* A1 = CLE high */
			this->IO_ADDR_W = (void __iomem *)REG_ADDR(pio,
				regi_pio, rw_io_access2);
		} else {
			/* A1 = CLE and A0 = ALE low */
			this->IO_ADDR_W = (void __iomem *)REG_ADDR(pio,
				regi_pio, rw_io_access0);
		}
#else

		dout.regf_CLE = (ctrl & NAND_CLE) ? 1 : 0;
		dout.regf_ALE = (ctrl & NAND_ALE) ? 1 : 0;
#endif
		REG_WR(pio, regi_pio, rw_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_pio_r_din din = REG_RD(pio, regi_pio, r_din);
	return din.rdy;
}

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

	struct mtd_info_wrapper *wrapper;
	struct nand_chip *this;
	int err = 0;

	reg_pio_rw_man_ctrl man_ctrl = {
		.regf_NCE = regk_pio_yes,
#if MANUAL_ALE_CLE_CONTROL
		.regf_ALE = regk_pio_yes,
		.regf_CLE = regk_pio_yes
#endif
	};
	reg_pio_rw_oe oe = {
		.regf_NCE = regk_pio_yes,
#if MANUAL_ALE_CLE_CONTROL
		.regf_ALE = regk_pio_yes,
		.regf_CLE = regk_pio_yes
#endif
	};
	reg_pio_rw_dout dout = { .regf_NCE = 1 };

	/* Allocate pio pins to pio */
	crisv32_pinmux_alloc_fixed(pinmux_pio);
	/* Set up CE, ALE, CLE (ce0_n, a0, a1) for manual control and output */
	REG_WR(pio, regi_pio, rw_man_ctrl, man_ctrl);
	REG_WR(pio, regi_pio, rw_dout, dout);
	REG_WR(pio, regi_pio, rw_oe, oe);

	/* 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 = write_cs = (void __iomem *)REG_ADDR(pio, regi_pio,
		rw_io_access0);

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

	/* 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_mtd;
	}

	return crisv32_mtd;

out_mtd:
	kfree(wrapper);
	return NULL;
}