/*
 *  linux/drivers/mtd/nand/cmx270-nand.c
 *
 *  Copyright (C) 2006 Compulab, Ltd.
 *  Mike Rapoport <mike@compulab.co.il>
 *
 *  Derived from drivers/mtd/nand/h1910.c
 *       Copyright (C) 2002 Marius Gröger (mag@sysgo.de)
 *       Copyright (c) 2001 Thomas Gleixner (gleixner@autronix.de)
 *
 *
 * 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.
 *
 *  Overview:
 *   This is a device driver for the NAND flash device found on the
 *   CM-X270 board.
 */

#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/module.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach-types.h>

#include <mach/pxa2xx-regs.h>

#define GPIO_NAND_CS    (11)
#define GPIO_NAND_RB    (89)

/* MTD structure for CM-X270 board */
static struct mtd_info *cmx270_nand_mtd;

/* remaped IO address of the device */
static void __iomem *cmx270_nand_io;

/*
 * Define static partitions for flash device
 */
static struct mtd_partition partition_info[] = {
        [0] = {
                .name   = "cmx270-0",
                .offset = 0,
                .size   = MTDPART_SIZ_FULL
        }
};
#define NUM_PARTITIONS (ARRAY_SIZE(partition_info))

static u_char cmx270_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *this = mtd_to_nand(mtd);

        return (readl(this->IO_ADDR_R) >> 16);
}

static void cmx270_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
{
        int i;
        struct nand_chip *this = mtd_to_nand(mtd);

        for (i=0; i<len; i++)
                writel((*buf++ << 16), this->IO_ADDR_W);
}

static void cmx270_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
        int i;
        struct nand_chip *this = mtd_to_nand(mtd);

        for (i=0; i<len; i++)
                *buf++ = readl(this->IO_ADDR_R) >> 16;
}

static inline void nand_cs_on(void)
{
        gpio_set_value(GPIO_NAND_CS, 0);
}

static void nand_cs_off(void)
{
        dsb();

        gpio_set_value(GPIO_NAND_CS, 1);
}

/*
 *      hardware specific access to control-lines
 */
static void cmx270_hwcontrol(struct mtd_info *mtd, int dat,
                             unsigned int ctrl)
{
        struct nand_chip *this = mtd_to_nand(mtd);
        unsigned int nandaddr = (unsigned int)this->IO_ADDR_W;

        dsb();

        if (ctrl & NAND_CTRL_CHANGE) {
                if ( ctrl & NAND_ALE )
                        nandaddr |=  (1 << 3);
                else
                        nandaddr &= ~(1 << 3);
                if ( ctrl & NAND_CLE )
                        nandaddr |=  (1 << 2);
                else
                        nandaddr &= ~(1 << 2);
                if ( ctrl & NAND_NCE )
                        nand_cs_on();
                else
                        nand_cs_off();
        }

        dsb();
        this->IO_ADDR_W = (void __iomem*)nandaddr;
        if (dat != NAND_CMD_NONE)
                writel((dat << 16), this->IO_ADDR_W);

        dsb();
}

/*
 *      read device ready pin
 */
static int cmx270_device_ready(struct mtd_info *mtd)
{
        dsb();

        return (gpio_get_value(GPIO_NAND_RB));
}

/*
 * Main initialization routine
 */
static int __init cmx270_init(void)
{
        struct nand_chip *this;
        int ret;

        if (!(machine_is_armcore() && cpu_is_pxa27x()))
                return -ENODEV;

        ret = gpio_request(GPIO_NAND_CS, "NAND CS");
        if (ret) {
                pr_warning("CM-X270: failed to request NAND CS gpio\n");
                return ret;
        }

        gpio_direction_output(GPIO_NAND_CS, 1);

        ret = gpio_request(GPIO_NAND_RB, "NAND R/B");
        if (ret) {
                pr_warning("CM-X270: failed to request NAND R/B gpio\n");
                goto err_gpio_request;
        }

        gpio_direction_input(GPIO_NAND_RB);

        /* Allocate memory for MTD device structure and private data */
        this = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
        if (!this) {
                ret = -ENOMEM;
                goto err_kzalloc;
        }

        cmx270_nand_io = ioremap(PXA_CS1_PHYS, 12);
        if (!cmx270_nand_io) {
                pr_debug("Unable to ioremap NAND device\n");
                ret = -EINVAL;
                goto err_ioremap;
        }

        cmx270_nand_mtd = nand_to_mtd(this);

        /* Link the private data with the MTD structure */
        cmx270_nand_mtd->owner = THIS_MODULE;

        /* insert callbacks */
        this->IO_ADDR_R = cmx270_nand_io;
        this->IO_ADDR_W = cmx270_nand_io;
        this->cmd_ctrl = cmx270_hwcontrol;
        this->dev_ready = cmx270_device_ready;

        /* 15 us command delay time */
        this->chip_delay = 20;
        this->ecc.mode = NAND_ECC_SOFT;

        /* read/write functions */
        this->read_byte = cmx270_read_byte;
        this->read_buf = cmx270_read_buf;
        this->write_buf = cmx270_write_buf;

        /* Scan to find existence of the device */
        if (nand_scan (cmx270_nand_mtd, 1)) {
                pr_notice("No NAND device\n");
                ret = -ENXIO;
                goto err_scan;
        }

        /* Register the partitions */
        ret = mtd_device_parse_register(cmx270_nand_mtd, NULL, NULL,
                                        partition_info, NUM_PARTITIONS);
        if (ret)
                goto err_scan;

        /* Return happy */
        return 0;

err_scan:
        iounmap(cmx270_nand_io);
err_ioremap:
        kfree(this);
err_kzalloc:
        gpio_free(GPIO_NAND_RB);
err_gpio_request:
        gpio_free(GPIO_NAND_CS);

        return ret;

}
module_init(cmx270_init);

/*
 * Clean up routine
 */
static void __exit cmx270_cleanup(void)
{
        /* Release resources, unregister device */
        nand_release(cmx270_nand_mtd);

        gpio_free(GPIO_NAND_RB);
        gpio_free(GPIO_NAND_CS);

        iounmap(cmx270_nand_io);

        kfree(mtd_to_nand(cmx270_nand_mtd));
}
module_exit(cmx270_cleanup);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
MODULE_DESCRIPTION("NAND flash driver for Compulab CM-X270 Module");