/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Author: Egor Martovetsky <egor@pasemi.com>
 * Maintained by: Olof Johansson <olof@lixom.net>
 *
 * Driver for the PWRficient onchip NAND flash interface
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#undef DEBUG

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pci.h>

#include <asm/io.h>

#define LBICTRL_LPCCTL_NR               0x00004000
#define CLE_PIN_CTL                     15
#define ALE_PIN_CTL                     14

static unsigned int lpcctl;
static struct mtd_info *pasemi_nand_mtd;
static const char driver_name[] = "pasemi-nand";

static void pasemi_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);

        while (len > 0x800) {
                memcpy_fromio(buf, chip->IO_ADDR_R, 0x800);
                buf += 0x800;
                len -= 0x800;
        }
        memcpy_fromio(buf, chip->IO_ADDR_R, len);
}

static void pasemi_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);

        while (len > 0x800) {
                memcpy_toio(chip->IO_ADDR_R, buf, 0x800);
                buf += 0x800;
                len -= 0x800;
        }
        memcpy_toio(chip->IO_ADDR_R, buf, len);
}

static void pasemi_hwcontrol(struct mtd_info *mtd, int cmd,
                             unsigned int ctrl)
{
        struct nand_chip *chip = mtd_to_nand(mtd);

        if (cmd == NAND_CMD_NONE)
                return;

        if (ctrl & NAND_CLE)
                out_8(chip->IO_ADDR_W + (1 << CLE_PIN_CTL), cmd);
        else
                out_8(chip->IO_ADDR_W + (1 << ALE_PIN_CTL), cmd);

        /* Push out posted writes */
        eieio();
        inl(lpcctl);
}

int pasemi_device_ready(struct mtd_info *mtd)
{
        return !!(inl(lpcctl) & LBICTRL_LPCCTL_NR);
}

static int pasemi_nand_probe(struct platform_device *ofdev)
{
        struct device *dev = &ofdev->dev;
        struct pci_dev *pdev;
        struct device_node *np = dev->of_node;
        struct resource res;
        struct nand_chip *chip;
        int err = 0;

        err = of_address_to_resource(np, 0, &res);

        if (err)
                return -EINVAL;

        /* We only support one device at the moment */
        if (pasemi_nand_mtd)
                return -ENODEV;

        dev_dbg(dev, "pasemi_nand at %pR\n", &res);

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

        pasemi_nand_mtd = nand_to_mtd(chip);

        /* Link the private data with the MTD structure */
        pasemi_nand_mtd->dev.parent = dev;

        chip->IO_ADDR_R = of_iomap(np, 0);
        chip->IO_ADDR_W = chip->IO_ADDR_R;

        if (!chip->IO_ADDR_R) {
                err = -EIO;
                goto out_mtd;
        }

        pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa008, NULL);
        if (!pdev) {
                err = -ENODEV;
                goto out_ior;
        }

        lpcctl = pci_resource_start(pdev, 0);
        pci_dev_put(pdev);

        if (!request_region(lpcctl, 4, driver_name)) {
                err = -EBUSY;
                goto out_ior;
        }

        chip->cmd_ctrl = pasemi_hwcontrol;
        chip->dev_ready = pasemi_device_ready;
        chip->read_buf = pasemi_read_buf;
        chip->write_buf = pasemi_write_buf;
        chip->chip_delay = 0;
        chip->ecc.mode = NAND_ECC_SOFT;
        chip->ecc.algo = NAND_ECC_HAMMING;

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

        /* Scan to find existence of the device */
        err = nand_scan(pasemi_nand_mtd, 1);
        if (err)
                goto out_lpc;

        if (mtd_device_register(pasemi_nand_mtd, NULL, 0)) {
                dev_err(dev, "Unable to register MTD device\n");
                err = -ENODEV;
                goto out_lpc;
        }

        dev_info(dev, "PA Semi NAND flash at %pR, control at I/O %x\n", &res,
                 lpcctl);

        return 0;

 out_lpc:
        release_region(lpcctl, 4);
 out_ior:
        iounmap(chip->IO_ADDR_R);
 out_mtd:
        kfree(chip);
 out:
        return err;
}

static int pasemi_nand_remove(struct platform_device *ofdev)
{
        struct nand_chip *chip;

        if (!pasemi_nand_mtd)
                return 0;

        chip = mtd_to_nand(pasemi_nand_mtd);

        /* Release resources, unregister device */
        nand_release(pasemi_nand_mtd);

        release_region(lpcctl, 4);

        iounmap(chip->IO_ADDR_R);

        /* Free the MTD device structure */
        kfree(chip);

        pasemi_nand_mtd = NULL;

        return 0;
}

static const struct of_device_id pasemi_nand_match[] =
{
        {
                .compatible   = "pasemi,localbus-nand",
        },
        {},
};

MODULE_DEVICE_TABLE(of, pasemi_nand_match);

static struct platform_driver pasemi_nand_driver =
{
        .driver = {
                .name = driver_name,
                .of_match_table = pasemi_nand_match,
        },
        .probe          = pasemi_nand_probe,
        .remove         = pasemi_nand_remove,
};

module_platform_driver(pasemi_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
MODULE_DESCRIPTION("NAND flash interface driver for PA Semi PWRficient");