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

#include <asm/io.h>
#include <asm/sizes.h>

#include <asm/hardware.h>
#include <asm/arch/board.h>
#include <asm/arch/gpio.h>

struct at91_nand_host {
 struct nand_chip nand_chip;
 struct mtd_info  mtd;
 void __iomem  *io_base;
 struct at91_nand_data *board;
};

/*
 * Hardware specific access to control-lines
 */
static void at91_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
 struct nand_chip *nand_chip = mtd->priv;
 struct at91_nand_host *host = nand_chip->priv;

 if (cmd == NAND_CMD_NONE)
  return;

 if (ctrl & NAND_CLE)
  writeb(cmd, host->io_base + (1 << host->board->cle));
 else
  writeb(cmd, host->io_base + (1 << host->board->ale));
}

/*
 * Read the Device Ready pin.
 */
static int at91_nand_device_ready(struct mtd_info *mtd)
{
 struct nand_chip *nand_chip = mtd->priv;
 struct at91_nand_host *host = nand_chip->priv;

 return at91_get_gpio_value(host->board->rdy_pin);
}

/*
 * Enable NAND.
 */
static void at91_nand_enable(struct at91_nand_host *host)
{
 if (host->board->enable_pin)
  at91_set_gpio_value(host->board->enable_pin, 0);
}

/*
 * Disable NAND.
 */
static void at91_nand_disable(struct at91_nand_host *host)
{
 if (host->board->enable_pin)
  at91_set_gpio_value(host->board->enable_pin, 1);
}

/*
 * Probe for the NAND device.
 */
static int __init at91_nand_probe(struct platform_device *pdev)
{
 struct at91_nand_host *host;
 struct mtd_info *mtd;
 struct nand_chip *nand_chip;
 int res;

#ifdef CONFIG_MTD_PARTITIONS
 struct mtd_partition *partitions = NULL;
 int num_partitions = 0;
#endif

 /* Allocate memory for the device structure (and zero it) */
 host = kzalloc(sizeof(struct at91_nand_host), GFP_KERNEL);
 if (!host) {
  printk(KERN_ERR "at91_nand: failed to allocate device structure.\n");
  return -ENOMEM;
 }

 host->io_base = ioremap(pdev->resource[0].start,
    pdev->resource[0].end - pdev->resource[0].start + 1);
 if (host->io_base == NULL) {
  printk(KERN_ERR "at91_nand: ioremap failed\n");
  kfree(host);
  return -EIO;
 }

 mtd = &host->mtd;
 nand_chip = &host->nand_chip;
 host->board = pdev->dev.platform_data;

 nand_chip->priv = host;  /* link the private data structures */
 mtd->priv = nand_chip;
 mtd->owner = THIS_MODULE;

 /* Set address of NAND IO lines */
 nand_chip->IO_ADDR_R = host->io_base;
 nand_chip->IO_ADDR_W = host->io_base;
 nand_chip->cmd_ctrl = at91_nand_cmd_ctrl;
 nand_chip->dev_ready = at91_nand_device_ready;
 nand_chip->ecc.mode = NAND_ECC_SOFT; /* enable ECC */
 nand_chip->chip_delay = 20;  /* 20us command delay time */

 if (host->board->bus_width_16)  /* 16-bit bus width */
  nand_chip->options |= NAND_BUSWIDTH_16;

 platform_set_drvdata(pdev, host);
 at91_nand_enable(host);

 if (host->board->det_pin) {
  if (at91_get_gpio_value(host->board->det_pin)) {
   printk ("No SmartMedia card inserted.\n");
   res = ENXIO;
   goto out;
  }
 }

 /* Scan to find existance of the device */
 if (nand_scan(mtd, 1)) {
  res = -ENXIO;
  goto out;
 }

#ifdef CONFIG_MTD_PARTITIONS
 if (host->board->partition_info)
  partitions = host->board->partition_info(mtd->size, &num_partitions);

 if ((!partitions) || (num_partitions == 0)) {
  printk(KERN_ERR "at91_nand: No parititions defined, or unsupported device.\n");
  res = ENXIO;
  goto release;
 }

 res = add_mtd_partitions(mtd, partitions, num_partitions);
#else
 res = add_mtd_device(mtd);
#endif

 if (!res)
  return res;

release:
 nand_release(mtd);
out:
 at91_nand_disable(host);
 platform_set_drvdata(pdev, NULL);
 iounmap(host->io_base);
 kfree(host);
 return res;
}

/*
 * Remove a NAND device.
 */
static int __devexit at91_nand_remove(struct platform_device *pdev)
{
 struct at91_nand_host *host = platform_get_drvdata(pdev);
 struct mtd_info *mtd = &host->mtd;

 nand_release(mtd);

 at91_nand_disable(host);

 iounmap(host->io_base);
 kfree(host);

 return 0;
}

static struct platform_driver at91_nand_driver = {
 .probe  = at91_nand_probe,
 .remove  = at91_nand_remove,
 .driver  = {
  .name = "at91_nand",
  .owner = THIS_MODULE,
 },
};

static int __init at91_nand_init(void)
{
 return platform_driver_register(&at91_nand_driver);
}


static void __exit at91_nand_exit(void)
{
 platform_driver_unregister(&at91_nand_driver);
}


module_init(at91_nand_init);
module_exit(at91_nand_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("NAND/SmartMedia driver for AT91RM9200");