/*
   * Interface for NOR flash driver whose high address lines are latched
   *
   * Copyright © 2000 Nicolas Pitre <nico@cam.org>
   * Copyright © 2005-2008 Analog Devices Inc.
   * Copyright © 2008 MontaVista Software, Inc. <source@mvista.com>
   *
   * This file is licensed under the terms of the GNU General Public License
   * version 2. This program is licensed "as is" without any warranty of any
   * kind, whether express or implied.
   */
  
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/map.h>
  #include <linux/mtd/partitions.h>
  #include <linux/platform_device.h>
  #include <linux/mtd/latch-addr-flash.h>
  #include <linux/slab.h>
  
  #define DRIVER_NAME "latch-addr-flash"
  
  struct latch_addr_flash_info {
  	struct mtd_info		*mtd;
  	struct map_info		map;
  	struct resource		*res;
  
  	void			(*set_window)(unsigned long offset, void *data);
  	void			*data;
  
  	/* cache; could be found out of res */
  	unsigned long		win_mask;
  
  	spinlock_t		lock;
  };
  
  static map_word lf_read(struct map_info *map, unsigned long ofs)
  {
  	struct latch_addr_flash_info *info;
  	map_word datum;
  
  	info = (struct latch_addr_flash_info *)map->map_priv_1;
  
  	spin_lock(&info->lock);
  
  	info->set_window(ofs, info->data);
  	datum = inline_map_read(map, info->win_mask & ofs);
  
  	spin_unlock(&info->lock);
  
  	return datum;
  }
  
  static void lf_write(struct map_info *map, map_word datum, unsigned long ofs)
  {
  	struct latch_addr_flash_info *info;
  
  	info = (struct latch_addr_flash_info *)map->map_priv_1;
  
  	spin_lock(&info->lock);
  
  	info->set_window(ofs, info->data);
  	inline_map_write(map, datum, info->win_mask & ofs);
  
  	spin_unlock(&info->lock);
  }
  
  static void lf_copy_from(struct map_info *map, void *to,
  		unsigned long from, ssize_t len)
  {
  	struct latch_addr_flash_info *info =
  		(struct latch_addr_flash_info *) map->map_priv_1;
  	unsigned n;
  
  	while (len > 0) {
  		n = info->win_mask + 1 - (from & info->win_mask);
  		if (n > len)
  			n = len;
  
  		spin_lock(&info->lock);
  
  		info->set_window(from, info->data);
  		memcpy_fromio(to, map->virt + (from & info->win_mask), n);
  
  		spin_unlock(&info->lock);
  
  		to += n;
  		from += n;
  		len -= n;
  	}
  }
  
  static char *rom_probe_types[] = { "cfi_probe", NULL };
  
  static int latch_addr_flash_remove(struct platform_device *dev)
  {
  	struct latch_addr_flash_info *info;
  	struct latch_addr_flash_data *latch_addr_data;
  
  	info = platform_get_drvdata(dev);
  	if (info == NULL)
  		return 0;
  
  	latch_addr_data = dev_get_platdata(&dev->dev);
  
  	if (info->mtd != NULL) {
  		mtd_device_unregister(info->mtd);
  		map_destroy(info->mtd);
  	}
  
  	if (info->map.virt != NULL)
  		iounmap(info->map.virt);
  
  	if (info->res != NULL)
  		release_mem_region(info->res->start, resource_size(info->res));
  
  	kfree(info);
  
  	if (latch_addr_data->done)
  		latch_addr_data->done(latch_addr_data->data);
  
  	return 0;
  }
  
  static int latch_addr_flash_probe(struct platform_device *dev)
  {
  	struct latch_addr_flash_data *latch_addr_data;
  	struct latch_addr_flash_info *info;
  	resource_size_t win_base = dev->resource->start;
  	resource_size_t win_size = resource_size(dev->resource);
  	char **probe_type;
  	int chipsel;
  	int err;
  
  	latch_addr_data = dev_get_platdata(&dev->dev);
  	if (latch_addr_data == NULL)
  		return -ENODEV;
  
  	pr_notice("latch-addr platform flash device: %#llx byte "
  		  "window at %#.8llx
  ",
  		  (unsigned long long)win_size, (unsigned long long)win_base);
  
  	chipsel = dev->id;
  
  	if (latch_addr_data->init) {
  		err = latch_addr_data->init(latch_addr_data->data, chipsel);
  		if (err != 0)
  			return err;
  	}
  
  	info = kzalloc(sizeof(struct latch_addr_flash_info), GFP_KERNEL);
  	if (info == NULL) {
  		err = -ENOMEM;
  		goto done;
  	}
  
  	platform_set_drvdata(dev, info);
  
  	info->res = request_mem_region(win_base, win_size, DRIVER_NAME);
  	if (info->res == NULL) {
  		dev_err(&dev->dev, "Could not reserve memory region
  ");
  		err = -EBUSY;
  		goto free_info;
  	}
  
  	info->map.name		= DRIVER_NAME;
  	info->map.size		= latch_addr_data->size;
  	info->map.bankwidth	= latch_addr_data->width;
  
  	info->map.phys		= NO_XIP;
  	info->map.virt		= ioremap(win_base, win_size);
  	if (!info->map.virt) {
  		err = -ENOMEM;
  		goto free_res;
  	}
  
  	info->map.map_priv_1	= (unsigned long)info;
  
  	info->map.read		= lf_read;
  	info->map.copy_from	= lf_copy_from;
  	info->map.write		= lf_write;
  	info->set_window	= latch_addr_data->set_window;
  	info->data		= latch_addr_data->data;
  	info->win_mask		= win_size - 1;
  
  	spin_lock_init(&info->lock);
  
  	for (probe_type = rom_probe_types; !info->mtd && *probe_type;
  		probe_type++)
  		info->mtd = do_map_probe(*probe_type, &info->map);
  
  	if (info->mtd == NULL) {
  		dev_err(&dev->dev, "map_probe failed
  ");
  		err = -ENODEV;
  		goto iounmap;
  	}
  	info->mtd->owner = THIS_MODULE;
  
  	mtd_device_parse_register(info->mtd, NULL, NULL,
  				  latch_addr_data->parts,
  				  latch_addr_data->nr_parts);
  	return 0;
  
  iounmap:
  	iounmap(info->map.virt);
  free_res:
  	release_mem_region(info->res->start, resource_size(info->res));
  free_info:
  	kfree(info);
  done:
  	if (latch_addr_data->done)
  		latch_addr_data->done(latch_addr_data->data);
  	return err;
  }
  
  static struct platform_driver latch_addr_flash_driver = {
  	.probe		= latch_addr_flash_probe,
  	.remove		= latch_addr_flash_remove,
  	.driver		= {
  		.name	= DRIVER_NAME,
  	},
  };
  
  module_platform_driver(latch_addr_flash_driver);
  
  MODULE_AUTHOR("David Griego <dgriego@mvista.com>");
  MODULE_DESCRIPTION("MTD map driver for flashes addressed physically with upper "
  		"address lines being set board specifically");
  MODULE_LICENSE("GPL v2");