/*

   * drivers/mtd/maps/ixp4xx.c
   *
   * MTD Map file for IXP4XX based systems. Please do not make per-board
   * changes in here. If your board needs special setup, do it in your
   * platform level code in arch/arm/mach-ixp4xx/board-setup.c
   *
   * Original Author: Intel Corporation
   * Maintainer: Deepak Saxena <dsaxena@mvista.com>
   *
   * Copyright (C) 2002 Intel Corporation
   * Copyright (C) 2003-2004 MontaVista Software, Inc.
   *
   */

  #include <linux/err.h>

  #include <linux/module.h>
  #include <linux/types.h>

  #include <linux/kernel.h>
  #include <linux/string.h>

  #include <linux/slab.h>
  #include <linux/ioport.h>
  #include <linux/device.h>

  #include <linux/platform_device.h>

  #include <linux/mtd/mtd.h>
  #include <linux/mtd/map.h>
  #include <linux/mtd/partitions.h>

  #include <asm/io.h>

  #include <asm/mach/flash.h>
  
  #include <linux/reboot.h>

  /*
   * Read/write a 16 bit word from flash address 'addr'.
   *
   * When the cpu is in little-endian mode it swizzles the address lines
   * ('address coherency') so we need to undo the swizzling to ensure commands
   * and the like end up on the correct flash address.
   *
   * To further complicate matters, due to the way the expansion bus controller
   * handles 32 bit reads, the byte stream ABCD is stored on the flash as:
   *     D15    D0
   *     +---+---+
   *     | A | B | 0
   *     +---+---+
   *     | C | D | 2
   *     +---+---+
   * This means that on LE systems each 16 bit word must be swapped. Note that
   * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI
   * data and other flash commands which are always in D7-D0.
   */

  #ifndef __ARMEB__

  #ifndef CONFIG_MTD_CFI_BE_BYTE_SWAP
  #  error CONFIG_MTD_CFI_BE_BYTE_SWAP required
  #endif
  
  static inline u16 flash_read16(void __iomem *addr)
  {
  	return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2)));
  }
  
  static inline void flash_write16(u16 d, void __iomem *addr)
  {
  	__raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2));
  }

  #define	BYTE0(h)	((h) & 0xFF)
  #define	BYTE1(h)	(((h) >> 8) & 0xFF)

  #else

  
  static inline u16 flash_read16(const void __iomem *addr)
  {
  	return __raw_readw(addr);
  }
  
  static inline void flash_write16(u16 d, void __iomem *addr)
  {
  	__raw_writew(d, addr);
  }

  #define	BYTE0(h)	(((h) >> 8) & 0xFF)
  #define	BYTE1(h)	((h) & 0xFF)
  #endif
  
  static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
  {
  	map_word val;

  	val.x[0] = flash_read16(map->virt + ofs);

  	return val;
  }
  
  /*
   * The IXP4xx expansion bus only allows 16-bit wide acceses
   * when attached to a 16-bit wide device (such as the 28F128J3A),
   * so we can't just memcpy_fromio().
   */
  static void ixp4xx_copy_from(struct map_info *map, void *to,
  			     unsigned long from, ssize_t len)
  {

  	u8 *dest = (u8 *) to;

  	void __iomem *src = map->virt + from;

  	if (len <= 0)
  		return;
  
  	if (from & 1) {

  		*dest++ = BYTE1(flash_read16(src-1));
  		src++;

  		--len;

  	}

  	while (len >= 2) {
  		u16 data = flash_read16(src);
  		*dest++ = BYTE0(data);
  		*dest++ = BYTE1(data);
  		src += 2;
  		len -= 2;

  	}

  
  	if (len > 0)
  		*dest++ = BYTE0(flash_read16(src));

  }

  /*

   * Unaligned writes are ignored, causing the 8-bit
   * probe to fail and proceed to the 16-bit probe (which succeeds).
   */
  static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr)
  {
  	if (!(adr & 1))

  		flash_write16(d.x[0], map->virt + adr);

  }

  /*

   * Fast write16 function without the probing check above
   */
  static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr)
  {

  	flash_write16(d.x[0], map->virt + adr);

  }
  
  struct ixp4xx_flash_info {
  	struct mtd_info *mtd;
  	struct map_info map;

  	struct resource *res;
  };

  static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL };

  static int ixp4xx_flash_remove(struct platform_device *dev)

  {

  	struct flash_platform_data *plat = dev_get_platdata(&dev->dev);

  	struct ixp4xx_flash_info *info = platform_get_drvdata(dev);

  	if(!info)
  		return 0;

  	if (info->mtd) {

  		mtd_device_unregister(info->mtd);

  		map_destroy(info->mtd);
  	}

  
  	if (plat->exit)
  		plat->exit();

  	return 0;
  }

  static int ixp4xx_flash_probe(struct platform_device *dev)

  {

  	struct flash_platform_data *plat = dev_get_platdata(&dev->dev);

  	struct ixp4xx_flash_info *info;

  	struct mtd_part_parser_data ppdata = {
  		.origin = dev->resource->start,
  	};

  	int err = -1;
  
  	if (!plat)
  		return -ENODEV;
  
  	if (plat->init) {
  		err = plat->init();
  		if (err)
  			return err;
  	}

  	info = devm_kzalloc(&dev->dev, sizeof(struct ixp4xx_flash_info),
  			    GFP_KERNEL);

  	if(!info) {
  		err = -ENOMEM;
  		goto Error;

  	}

  	platform_set_drvdata(dev, info);

  	/*
  	 * Tell the MTD layer we're not 1:1 mapped so that it does
  	 * not attempt to do a direct access on us.
  	 */
  	info->map.phys = NO_XIP;

  	info->map.size = resource_size(dev->resource);

  
  	/*
  	 * We only support 16-bit accesses for now. If and when
  	 * any board use 8-bit access, we'll fixup the driver to
  	 * handle that.
  	 */
  	info->map.bankwidth = 2;

  	info->map.name = dev_name(&dev->dev);

  	info->map.read = ixp4xx_read16;
  	info->map.write = ixp4xx_probe_write16;
  	info->map.copy_from = ixp4xx_copy_from;

  	info->map.virt = devm_ioremap_resource(&dev->dev, dev->resource);
  	if (IS_ERR(info->map.virt)) {
  		err = PTR_ERR(info->map.virt);

  		goto Error;
  	}
  
  	info->mtd = do_map_probe(plat->map_name, &info->map);
  	if (!info->mtd) {
  		printk(KERN_ERR "IXP4XXFlash: map_probe failed
  ");
  		err = -ENXIO;
  		goto Error;
  	}

  	info->mtd->dev.parent = &dev->dev;

  	/* Use the fast version */

  	info->map.write = ixp4xx_write16;

  	err = mtd_device_parse_register(info->mtd, probes, &ppdata,

  			plat->parts, plat->nr_parts);
  	if (err) {

  		printk(KERN_ERR "Could not parse partitions
  ");

  		goto Error;

  	}

  
  	return 0;
  
  Error:

  	ixp4xx_flash_remove(dev);

  	return err;
  }

  static struct platform_driver ixp4xx_flash_driver = {

  	.probe		= ixp4xx_flash_probe,
  	.remove		= ixp4xx_flash_remove,

  	.driver		= {
  		.name	= "IXP4XX-Flash",
  	},

  };

  module_platform_driver(ixp4xx_flash_driver);

  
  MODULE_LICENSE("GPL");

  MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");

  MODULE_AUTHOR("Deepak Saxena");

  MODULE_ALIAS("platform:IXP4XX-Flash");