cmx270_nand.c

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/*
 *  linux/drivers/mtd/nand/cmx270-nand.c
 *
 *  Copyright (C) 2006 Compulab, Ltd.
 *  Mike Rapoport <[email protected]>
 *
 *  Derived from drivers/mtd/nand/h1910.c
 *       Copyright (C) 2002 Marius Gröger ([email protected])
 *       Copyright (c) 2001 Thomas Gleixner ([email protected])
 *
 *
 * 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->priv;

    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->priv;

    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->priv;

    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->priv;
    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 */
    cmx270_nand_mtd = kzalloc(sizeof(struct mtd_info) +
                  sizeof(struct nand_chip),
                  GFP_KERNEL);
    if (!cmx270_nand_mtd) {
        pr_debug("Unable to allocate CM-X270 NAND MTD device structure.\n");
        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;
    }

    /* Get pointer to private data */
    this = (struct nand_chip *)(&cmx270_nand_mtd[1]);

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

    /* 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(cmx270_nand_mtd);
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);

    /* Free the MTD device structure */
    kfree (cmx270_nand_mtd);
}
module_exit(cmx270_cleanup);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike Rapoport <[email protected]>");
MODULE_DESCRIPTION("NAND flash driver for Compulab CM-X270 Module");