/* 
 * mtdram - a test mtd device
 * $Id: mtdram.c,v 1.13 2000/07/03 10:01:38 dwmw2 Exp $
 * Author: Alexander Larsson <alex@cendio.se> 
 *
 * Copyright (c) 1999 Alexander Larsson <alex@cendio.se>
 *
 * This code is GPL
 *
 */

#include <linux/module.h>

#include <linux/malloc.h>
#include <linux/ioport.h>
#include <linux/mtd/compatmac.h>
#include <linux/mtd/mtd.h>


#define MTDRAM_TOTAL_SIZE 1024*1024*8
#define MTDRAM_ERASE_SIZE 4*1024


// We could store these in the mtd structure, but we only support 1 device..
static struct mtd_info *mtd_info;


static int
ram_erase(struct mtd_info *mtd, struct erase_info *instr)
{
  if (instr->addr + instr->len > mtd->size)
    return -EINVAL;
	
  memset((char *)mtd->priv + instr->addr, 0xff, instr->len);
  
  instr->state = MTD_ERASE_DONE;

  if (instr->callback)
    (*(instr->callback))(instr);
  return 0;
}

static int ram_point (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf)
{
  if (from + len > mtd->size)
    return -EINVAL;
  
  *mtdbuf = mtd->priv + from;
  *retlen = len;
  return 0;
}

static void ram_unpoint (struct mtd_info *mtd, u_char *addr)
{
}

static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
	     size_t *retlen, u_char *buf)
{
  if (from + len > mtd->size)
    return -EINVAL;

  memcpy(buf, mtd->priv + from, len);

  *retlen=len;
  return 0;
}

static int ram_write(struct mtd_info *mtd, loff_t to, size_t len,
	      size_t *retlen, const u_char *buf)
{
  if (to + len > mtd->size)
    return -EINVAL;
  
  memcpy ((char *)mtd->priv + to, buf, len);

  *retlen=len;
  return 0;
}

#if LINUX_VERSION_CODE < 0x20300
#ifdef MODULE
#define init_mtdram init_module
#define cleanup_mtdram cleanup_module
#endif
#endif

//static void __exit cleanup_mtdram(void)
mod_exit_t cleanup_mtdram(void)
{
  if (mtd_info) {
    del_mtd_device(mtd_info);
    if (mtd_info->priv)
      vfree(mtd_info->priv);
    kfree(mtd_info);
  }
}

extern struct module __this_module;

mod_init_t init_mtdram(void)
{
   // Allocate some memory
   mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
   if (mtd_info == 0)
      return 0;
   
   memset(mtd_info, 0, sizeof(*mtd_info));

   // Setup the MTD structure
   mtd_info->name = "mtdram test device";
   mtd_info->type = MTD_RAM;
   mtd_info->flags = MTD_CAP_RAM;
   mtd_info->size = MTDRAM_TOTAL_SIZE;
   mtd_info->erasesize = MTDRAM_ERASE_SIZE;
   mtd_info->priv = vmalloc(MTDRAM_TOTAL_SIZE);
   memset(mtd_info->priv, 0xff, MTDRAM_TOTAL_SIZE);

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
   mtd_info->module = THIS_MODULE;			
#endif

   if (!mtd_info->priv) {
     kfree(mtd_info);
     mtd_info = NULL;
     return -ENOMEM;
   }
   mtd_info->erase = ram_erase;
   mtd_info->point = ram_point;
   mtd_info->unpoint = ram_unpoint;
   mtd_info->read = ram_read;
   mtd_info->write = ram_write;

   if (add_mtd_device(mtd_info)) {
     vfree(mtd_info->priv);
     kfree(mtd_info);
     mtd_info = NULL;
     return -EIO;
   }
   
   return 0;
}

#if LINUX_VERSION_CODE > 0x20300
module_init(init_mtdram);
module_exit(cleanup_mtdram);
#endif