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/*

 *  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 <asm/io.h>

#include <asm/irq.h>

#include <asm/arch/hardware.h>

#include <asm/arch/pxa-regs.h>

#define GPIO_NAND_CS    (11)

#define GPIO_NAND_RB    (89)

/* This macro needed to ensure in-order operation of GPIO and local

 * bus. Without both asm command and dummy uncached read there're

 * states when NAND access is broken. I've looked for such macro(s) in

 * include/asm-arm but found nothing approptiate.

 * dmac_clean_range is close, but is makes cache invalidation

 * unnecessary here and it cannot be used in module

 */

#define DRAIN_WB() \

        do { \

                unsigned char dummy; \

                asm volatile ("mcr p15, 0, r0, c7, c10, 4":::"r0"); \

                dummy=*((unsigned char*)UNCACHED_ADDR); \

        } while(0)

/* 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))

const char *part_probes[] = { "cmdlinepart", NULL };

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 int cmx270_verify_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++)

                if (buf[i] != (u_char)(readl(this->IO_ADDR_R) >> 16))

                        return -EFAULT;

        return 0;

}

static inline void nand_cs_on(void)

{

        GPCR(GPIO_NAND_CS) = GPIO_bit(GPIO_NAND_CS);

}

static void nand_cs_off(void)

{

        DRAIN_WB();

        GPSR(GPIO_NAND_CS) = GPIO_bit(GPIO_NAND_CS);

}

/*

 *      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;

        DRAIN_WB();

        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();

        }

        DRAIN_WB();

        this->IO_ADDR_W = (void __iomem*)nandaddr;

        if (dat != NAND_CMD_NONE)

                writel((dat << 16), this->IO_ADDR_W);

        DRAIN_WB();

}

/*

 *      read device ready pin

 */

static int cmx270_device_ready(struct mtd_info *mtd)

{

        DRAIN_WB();

        return (GPLR(GPIO_NAND_RB) & GPIO_bit(GPIO_NAND_RB));

}

/*

 * Main initialization routine

 */

static int cmx270_init(void)

{

        struct nand_chip *this;

        const char *part_type;

        struct mtd_partition *mtd_parts;

        int mtd_parts_nb = 0;

        int ret;

        /* 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) {

                printk("Unable to allocate CM-X270 NAND MTD device structure.\n");

                return -ENOMEM;

        }

        cmx270_nand_io = ioremap(PXA_CS1_PHYS, 12);

        if (!cmx270_nand_io) {

                printk("Unable to ioremap NAND device\n");

                ret = -EINVAL;

                goto err1;

        }

        /* 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;

        this->verify_buf = cmx270_verify_buf;

        /* Scan to find existence of the device */

        if (nand_scan (cmx270_nand_mtd, 1)) {

                printk(KERN_NOTICE "No NAND device\n");

                ret = -ENXIO;

                goto err2;

        }

#ifdef CONFIG_MTD_CMDLINE_PARTS

        mtd_parts_nb = parse_mtd_partitions(cmx270_nand_mtd, part_probes,

                                            &mtd_parts, 0);

        if (mtd_parts_nb > 0)

                part_type = "command line";

        else

                mtd_parts_nb = 0;

#endif

        if (!mtd_parts_nb) {

                mtd_parts = partition_info;

                mtd_parts_nb = NUM_PARTITIONS;

                part_type = "static";

        }

        /* Register the partitions */

        printk(KERN_NOTICE "Using %s partition definition\n", part_type);

        ret = add_mtd_partitions(cmx270_nand_mtd, mtd_parts, mtd_parts_nb);

        if (ret)

                goto err2;

        /* Return happy */

        return 0;

err2:

        iounmap(cmx270_nand_io);

err1:

        kfree(cmx270_nand_mtd);

        return ret;

}

module_init(cmx270_init);

/*

 * Clean up routine

 */

static void cmx270_cleanup(void)

{

        /* Release resources, unregister device */

        nand_release(cmx270_nand_mtd);

        iounmap(cmx270_nand_io);

        /* Free the MTD device structure */

        kfree (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");