/*
   *  drivers/mtd/nand/ams-delta.c
   *
   *  Copyright (C) 2006 Jonathan McDowell <noodles@earth.li>
   *
   *  Derived from drivers/mtd/toto.c
   *  Converted to platform driver by Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
   *  Partially stolen from drivers/mtd/nand/plat_nand.c
   *
   * 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
   *   Amstrad E3 (Delta).
   */
  
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/nand.h>
  #include <linux/mtd/partitions.h>
  #include <linux/gpio.h>
  #include <linux/platform_data/gpio-omap.h>
  
  #include <asm/io.h>
  #include <asm/sizes.h>
  
  #include <mach/board-ams-delta.h>
  
  #include <mach/hardware.h>
  
  /*
   * MTD structure for E3 (Delta)
   */
  static struct mtd_info *ams_delta_mtd = NULL;
  
  /*
   * Define partitions for flash devices
   */
  
  static struct mtd_partition partition_info[] = {
  	{ .name		= "Kernel",
  	  .offset	= 0,
  	  .size		= 3 * SZ_1M + SZ_512K },
  	{ .name		= "u-boot",
  	  .offset	= 3 * SZ_1M + SZ_512K,
  	  .size		= SZ_256K },
  	{ .name		= "u-boot params",
  	  .offset	= 3 * SZ_1M + SZ_512K + SZ_256K,
  	  .size		= SZ_256K },
  	{ .name		= "Amstrad LDR",
  	  .offset	= 4 * SZ_1M,
  	  .size		= SZ_256K },
  	{ .name		= "File system",
  	  .offset	= 4 * SZ_1M + 1 * SZ_256K,
  	  .size		= 27 * SZ_1M },
  	{ .name		= "PBL reserved",
  	  .offset	= 32 * SZ_1M - 3 * SZ_256K,
  	  .size		=  3 * SZ_256K },
  };
  
  static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
  {
  	struct nand_chip *this = mtd->priv;
  	void __iomem *io_base = this->priv;
  
  	writew(0, io_base + OMAP_MPUIO_IO_CNTL);
  	writew(byte, this->IO_ADDR_W);
  	gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NWE, 0);
  	ndelay(40);
  	gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NWE, 1);
  }
  
  static u_char ams_delta_read_byte(struct mtd_info *mtd)
  {
  	u_char res;
  	struct nand_chip *this = mtd->priv;
  	void __iomem *io_base = this->priv;
  
  	gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NRE, 0);
  	ndelay(40);
  	writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
  	res = readw(this->IO_ADDR_R);
  	gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NRE, 1);
  
  	return res;
  }
  
  static void ams_delta_write_buf(struct mtd_info *mtd, const u_char *buf,
  				int len)
  {
  	int i;
  
  	for (i=0; i<len; i++)
  		ams_delta_write_byte(mtd, buf[i]);
  }
  
  static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
  {
  	int i;
  
  	for (i=0; i<len; i++)
  		buf[i] = ams_delta_read_byte(mtd);
  }
  
  /*
   * Command control function
   *
   * ctrl:
   * NAND_NCE: bit 0 -> bit 2
   * NAND_CLE: bit 1 -> bit 7
   * NAND_ALE: bit 2 -> bit 6
   */
  static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
  				unsigned int ctrl)
  {
  
  	if (ctrl & NAND_CTRL_CHANGE) {
  		gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NCE,
  				(ctrl & NAND_NCE) == 0);
  		gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_CLE,
  				(ctrl & NAND_CLE) != 0);
  		gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_ALE,
  				(ctrl & NAND_ALE) != 0);
  	}
  
  	if (cmd != NAND_CMD_NONE)
  		ams_delta_write_byte(mtd, cmd);
  }
  
  static int ams_delta_nand_ready(struct mtd_info *mtd)
  {
  	return gpio_get_value(AMS_DELTA_GPIO_PIN_NAND_RB);
  }
  
  static const struct gpio _mandatory_gpio[] = {
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_NCE,
  		.flags	= GPIOF_OUT_INIT_HIGH,
  		.label	= "nand_nce",
  	},
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_NRE,
  		.flags	= GPIOF_OUT_INIT_HIGH,
  		.label	= "nand_nre",
  	},
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_NWP,
  		.flags	= GPIOF_OUT_INIT_HIGH,
  		.label	= "nand_nwp",
  	},
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_NWE,
  		.flags	= GPIOF_OUT_INIT_HIGH,
  		.label	= "nand_nwe",
  	},
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_ALE,
  		.flags	= GPIOF_OUT_INIT_LOW,
  		.label	= "nand_ale",
  	},
  	{
  		.gpio	= AMS_DELTA_GPIO_PIN_NAND_CLE,
  		.flags	= GPIOF_OUT_INIT_LOW,
  		.label	= "nand_cle",
  	},
  };
  
  /*
   * Main initialization routine
   */
  static int ams_delta_init(struct platform_device *pdev)
  {
  	struct nand_chip *this;
  	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	void __iomem *io_base;
  	int err = 0;
  
  	if (!res)
  		return -ENXIO;
  
  	/* Allocate memory for MTD device structure and private data */
  	ams_delta_mtd = kmalloc(sizeof(struct mtd_info) +
  				sizeof(struct nand_chip), GFP_KERNEL);
  	if (!ams_delta_mtd) {
  		printk (KERN_WARNING "Unable to allocate E3 NAND MTD device structure.
  ");
  		err = -ENOMEM;
  		goto out;
  	}
  
  	ams_delta_mtd->owner = THIS_MODULE;
  
  	/* Get pointer to private data */
  	this = (struct nand_chip *) (&ams_delta_mtd[1]);
  
  	/* Initialize structures */
  	memset(ams_delta_mtd, 0, sizeof(struct mtd_info));
  	memset(this, 0, sizeof(struct nand_chip));
  
  	/* Link the private data with the MTD structure */
  	ams_delta_mtd->priv = this;
  
  	/*
  	 * Don't try to request the memory region from here,
  	 * it should have been already requested from the
  	 * gpio-omap driver and requesting it again would fail.
  	 */
  
  	io_base = ioremap(res->start, resource_size(res));
  	if (io_base == NULL) {
  		dev_err(&pdev->dev, "ioremap failed
  ");
  		err = -EIO;
  		goto out_free;
  	}
  
  	this->priv = io_base;
  
  	/* Set address of NAND IO lines */
  	this->IO_ADDR_R = io_base + OMAP_MPUIO_INPUT_LATCH;
  	this->IO_ADDR_W = io_base + OMAP_MPUIO_OUTPUT;
  	this->read_byte = ams_delta_read_byte;
  	this->write_buf = ams_delta_write_buf;
  	this->read_buf = ams_delta_read_buf;
  	this->cmd_ctrl = ams_delta_hwcontrol;
  	if (gpio_request(AMS_DELTA_GPIO_PIN_NAND_RB, "nand_rdy") == 0) {
  		this->dev_ready = ams_delta_nand_ready;
  	} else {
  		this->dev_ready = NULL;
  		printk(KERN_NOTICE "Couldn't request gpio for Delta NAND ready.
  ");
  	}
  	/* 25 us command delay time */
  	this->chip_delay = 30;
  	this->ecc.mode = NAND_ECC_SOFT;
  
  	platform_set_drvdata(pdev, io_base);
  
  	/* Set chip enabled, but  */
  	err = gpio_request_array(_mandatory_gpio, ARRAY_SIZE(_mandatory_gpio));
  	if (err)
  		goto out_gpio;
  
  	/* Scan to find existence of the device */
  	if (nand_scan(ams_delta_mtd, 1)) {
  		err = -ENXIO;
  		goto out_mtd;
  	}
  
  	/* Register the partitions */
  	mtd_device_register(ams_delta_mtd, partition_info,
  			    ARRAY_SIZE(partition_info));
  
  	goto out;
  
   out_mtd:
  	gpio_free_array(_mandatory_gpio, ARRAY_SIZE(_mandatory_gpio));
  out_gpio:
  	gpio_free(AMS_DELTA_GPIO_PIN_NAND_RB);
  	iounmap(io_base);
  out_free:
  	kfree(ams_delta_mtd);
   out:
  	return err;
  }
  
  /*
   * Clean up routine
   */
  static int ams_delta_cleanup(struct platform_device *pdev)
  {
  	void __iomem *io_base = platform_get_drvdata(pdev);
  
  	/* Release resources, unregister device */
  	nand_release(ams_delta_mtd);
  
  	gpio_free_array(_mandatory_gpio, ARRAY_SIZE(_mandatory_gpio));
  	gpio_free(AMS_DELTA_GPIO_PIN_NAND_RB);
  	iounmap(io_base);
  
  	/* Free the MTD device structure */
  	kfree(ams_delta_mtd);
  
  	return 0;
  }
  
  static struct platform_driver ams_delta_nand_driver = {
  	.probe		= ams_delta_init,
  	.remove		= ams_delta_cleanup,
  	.driver		= {
  		.name	= "ams-delta-nand",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver(ams_delta_nand_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Jonathan McDowell <noodles@earth.li>");
  MODULE_DESCRIPTION("Glue layer for NAND flash on Amstrad E3 (Delta)");