/*
  ** z2ram - Amiga pseudo-driver to access 16bit-RAM in ZorroII space
  **         as a block device, to be used as a RAM disk or swap space
  ** 
  ** Copyright (C) 1994 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)
  **
  ** ++Geert: support for zorro_unused_z2ram, better range checking
  ** ++roman: translate accesses via an array
  ** ++Milan: support for ChipRAM usage
  ** ++yambo: converted to 2.0 kernel
  ** ++yambo: modularized and support added for 3 minor devices including:
  **          MAJOR  MINOR  DESCRIPTION
  **          -----  -----  ----------------------------------------------
  **          37     0       Use Zorro II and Chip ram
  **          37     1       Use only Zorro II ram
  **          37     2       Use only Chip ram
  **          37     4-7     Use memory list entry 1-4 (first is 0)
  ** ++jskov: support for 1-4th memory list entry.
  **
  ** Permission to use, copy, modify, and distribute this software and its
  ** documentation for any purpose and without fee is hereby granted, provided
  ** that the above copyright notice appear in all copies and that both that
  ** copyright notice and this permission notice appear in supporting
  ** documentation.  This software is provided "as is" without express or
  ** implied warranty.
  */
  
  #define DEVICE_NAME "Z2RAM"
  
  #include <linux/major.h>
  #include <linux/vmalloc.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/blkdev.h>
  #include <linux/bitops.h>

  #include <linux/mutex.h>

  #include <linux/slab.h>

  
  #include <asm/setup.h>
  #include <asm/amigahw.h>
  #include <asm/pgtable.h>
  
  #include <linux/zorro.h>

  #define Z2MINOR_COMBINED      (0)
  #define Z2MINOR_Z2ONLY        (1)
  #define Z2MINOR_CHIPONLY      (2)
  #define Z2MINOR_MEMLIST1      (4)
  #define Z2MINOR_MEMLIST2      (5)
  #define Z2MINOR_MEMLIST3      (6)
  #define Z2MINOR_MEMLIST4      (7)
  #define Z2MINOR_COUNT         (8) /* Move this down when adding a new minor */
  
  #define Z2RAM_CHUNK1024       ( Z2RAM_CHUNKSIZE >> 10 )

  static DEFINE_MUTEX(z2ram_mutex);

  static u_long *z2ram_map    = NULL;
  static u_long z2ram_size    = 0;
  static int z2_count         = 0;
  static int chip_count       = 0;
  static int list_count       = 0;
  static int current_device   = -1;
  
  static DEFINE_SPINLOCK(z2ram_lock);

  static struct gendisk *z2ram_gendisk;

  static void do_z2_request(struct request_queue *q)

  {
  	struct request *req;

  	req = blk_fetch_request(q);

  	while (req) {

  		unsigned long start = blk_rq_pos(req) << 9;

  		unsigned long len  = blk_rq_cur_bytes(req);

  		blk_status_t err = BLK_STS_OK;

  
  		if (start + len > z2ram_size) {

  			pr_err(DEVICE_NAME ": bad access: block=%llu, "
  			       "count=%u
  ",
  			       (unsigned long long)blk_rq_pos(req),
  			       blk_rq_cur_sectors(req));

  			err = BLK_STS_IOERR;

  			goto done;

  		}
  		while (len) {
  			unsigned long addr = start & Z2RAM_CHUNKMASK;
  			unsigned long size = Z2RAM_CHUNKSIZE - addr;

  			void *buffer = bio_data(req->bio);

  			if (len < size)
  				size = len;
  			addr += z2ram_map[ start >> Z2RAM_CHUNKSHIFT ];
  			if (rq_data_dir(req) == READ)

  				memcpy(buffer, (char *)addr, size);

  			else

  				memcpy((char *)addr, buffer, size);

  			start += size;
  			len -= size;
  		}

  	done:

  		if (!__blk_end_request_cur(req, err))
  			req = blk_fetch_request(q);

  	}
  }
  
  static void
  get_z2ram( void )
  {
      int i;
  
      for ( i = 0; i < Z2RAM_SIZE / Z2RAM_CHUNKSIZE; i++ )
      {
  	if ( test_bit( i, zorro_unused_z2ram ) )
  	{
  	    z2_count++;

  	    z2ram_map[z2ram_size++] = (unsigned long)ZTWO_VADDR(Z2RAM_START) +
  				      (i << Z2RAM_CHUNKSHIFT);

  	    clear_bit( i, zorro_unused_z2ram );
  	}
      }
  
      return;
  }
  
  static void
  get_chipram( void )
  {
  
      while ( amiga_chip_avail() > ( Z2RAM_CHUNKSIZE * 4 ) )
      {
  	chip_count++;
  	z2ram_map[ z2ram_size ] =
  	    (u_long)amiga_chip_alloc( Z2RAM_CHUNKSIZE, "z2ram" );
  
  	if ( z2ram_map[ z2ram_size ] == 0 )
  	{
  	    break;
  	}
  
  	z2ram_size++;
      }
  	
      return;
  }

  static int z2_open(struct block_device *bdev, fmode_t mode)

  {
      int device;
      int max_z2_map = ( Z2RAM_SIZE / Z2RAM_CHUNKSIZE ) *
  	sizeof( z2ram_map[0] );
      int max_chip_map = ( amiga_chip_size / Z2RAM_CHUNKSIZE ) *
  	sizeof( z2ram_map[0] );
      int rc = -ENOMEM;

      device = MINOR(bdev->bd_dev);

      mutex_lock(&z2ram_mutex);

      if ( current_device != -1 && current_device != device )
      {
  	rc = -EBUSY;
  	goto err_out;
      }
  
      if ( current_device == -1 )
      {
  	z2_count   = 0;
  	chip_count = 0;
  	list_count = 0;
  	z2ram_size = 0;
  
  	/* Use a specific list entry. */
  	if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
  		int index = device - Z2MINOR_MEMLIST1 + 1;
  		unsigned long size, paddr, vaddr;
  
  		if (index >= m68k_realnum_memory) {
  			printk( KERN_ERR DEVICE_NAME
  				": no such entry in z2ram_map
  " );
  		        goto err_out;
  		}
  
  		paddr = m68k_memory[index].addr;
  		size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE-1);
  
  #ifdef __powerpc__
  		/* FIXME: ioremap doesn't build correct memory tables. */
  		{
  			vfree(vmalloc (size));
  		}
  
  		vaddr = (unsigned long) __ioremap (paddr, size, 
  						   _PAGE_WRITETHRU);
  
  #else
  		vaddr = (unsigned long)z_remap_nocache_nonser(paddr, size);
  #endif
  		z2ram_map = 
  			kmalloc((size/Z2RAM_CHUNKSIZE)*sizeof(z2ram_map[0]),
  				GFP_KERNEL);
  		if ( z2ram_map == NULL )
  		{
  		    printk( KERN_ERR DEVICE_NAME
  			": cannot get mem for z2ram_map
  " );
  		    goto err_out;
  		}
  
  		while (size) {
  			z2ram_map[ z2ram_size++ ] = vaddr;
  			size -= Z2RAM_CHUNKSIZE;
  			vaddr += Z2RAM_CHUNKSIZE;
  			list_count++;
  		}
  
  		if ( z2ram_size != 0 )
  		    printk( KERN_INFO DEVICE_NAME
  			": using %iK List Entry %d Memory
  ",
  			list_count * Z2RAM_CHUNK1024, index );
  	} else
  
  	switch ( device )
  	{
  	    case Z2MINOR_COMBINED:
  
  		z2ram_map = kmalloc( max_z2_map + max_chip_map, GFP_KERNEL );
  		if ( z2ram_map == NULL )
  		{
  		    printk( KERN_ERR DEVICE_NAME
  			": cannot get mem for z2ram_map
  " );
  		    goto err_out;
  		}
  
  		get_z2ram();
  		get_chipram();
  
  		if ( z2ram_size != 0 )
  		    printk( KERN_INFO DEVICE_NAME 
  			": using %iK Zorro II RAM and %iK Chip RAM (Total %dK)
  ",
  			z2_count * Z2RAM_CHUNK1024,
  			chip_count * Z2RAM_CHUNK1024,
  			( z2_count + chip_count ) * Z2RAM_CHUNK1024 );
  
  	    break;
  
      	    case Z2MINOR_Z2ONLY:
  		z2ram_map = kmalloc( max_z2_map, GFP_KERNEL );
  		if ( z2ram_map == NULL )
  		{
  		    printk( KERN_ERR DEVICE_NAME
  			": cannot get mem for z2ram_map
  " );
  		    goto err_out;
  		}
  
  		get_z2ram();
  
  		if ( z2ram_size != 0 )
  		    printk( KERN_INFO DEVICE_NAME 
  			": using %iK of Zorro II RAM
  ",
  			z2_count * Z2RAM_CHUNK1024 );
  
  	    break;
  
  	    case Z2MINOR_CHIPONLY:
  		z2ram_map = kmalloc( max_chip_map, GFP_KERNEL );
  		if ( z2ram_map == NULL )
  		{
  		    printk( KERN_ERR DEVICE_NAME
  			": cannot get mem for z2ram_map
  " );
  		    goto err_out;
  		}
  
  		get_chipram();
  
  		if ( z2ram_size != 0 )
  		    printk( KERN_INFO DEVICE_NAME 
  			": using %iK Chip RAM
  ",
  			chip_count * Z2RAM_CHUNK1024 );
  		    
  	    break;
  
  	    default:
  		rc = -ENODEV;
  		goto err_out;
  	
  	    break;
  	}
  
  	if ( z2ram_size == 0 )
  	{
  	    printk( KERN_NOTICE DEVICE_NAME
  		": no unused ZII/Chip RAM found
  " );
  	    goto err_out_kfree;
  	}
  
  	current_device = device;
  	z2ram_size <<= Z2RAM_CHUNKSHIFT;
  	set_capacity(z2ram_gendisk, z2ram_size >> 9);
      }

      mutex_unlock(&z2ram_mutex);

      return 0;
  
  err_out_kfree:

      kfree(z2ram_map);

  err_out:

      mutex_unlock(&z2ram_mutex);

      return rc;
  }

  static void

  z2_release(struct gendisk *disk, fmode_t mode)

  {

      mutex_lock(&z2ram_mutex);

      if ( current_device == -1 ) {

      	mutex_unlock(&z2ram_mutex);

      	return;

      }

      mutex_unlock(&z2ram_mutex);

      /*
       * FIXME: unmap memory
       */

  }

  static const struct block_device_operations z2_fops =

  {
  	.owner		= THIS_MODULE,

  	.open		= z2_open,
  	.release	= z2_release,

  };
  
  static struct kobject *z2_find(dev_t dev, int *part, void *data)
  {
  	*part = 0;
  	return get_disk(z2ram_gendisk);
  }
  
  static struct request_queue *z2_queue;

  static int __init 

  z2_init(void)
  {
      int ret;
  
      if (!MACH_IS_AMIGA)

  	return -ENODEV;

  
      ret = -EBUSY;
      if (register_blkdev(Z2RAM_MAJOR, DEVICE_NAME))
  	goto err;
  
      ret = -ENOMEM;
      z2ram_gendisk = alloc_disk(1);
      if (!z2ram_gendisk)
  	goto out_disk;
  
      z2_queue = blk_init_queue(do_z2_request, &z2ram_lock);
      if (!z2_queue)
  	goto out_queue;
  
      z2ram_gendisk->major = Z2RAM_MAJOR;
      z2ram_gendisk->first_minor = 0;
      z2ram_gendisk->fops = &z2_fops;
      sprintf(z2ram_gendisk->disk_name, "z2ram");

  
      z2ram_gendisk->queue = z2_queue;
      add_disk(z2ram_gendisk);
      blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE,
  				z2_find, NULL, NULL);
  
      return 0;
  
  out_queue:
      put_disk(z2ram_gendisk);
  out_disk:
      unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
  err:
      return ret;
  }

  static void __exit z2_exit(void)

  {
      int i, j;

      blk_unregister_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT);

      unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);

      del_gendisk(z2ram_gendisk);
      put_disk(z2ram_gendisk);
      blk_cleanup_queue(z2_queue);
  
      if ( current_device != -1 )
      {
  	i = 0;
  
  	for ( j = 0 ; j < z2_count; j++ )
  	{
  	    set_bit( i++, zorro_unused_z2ram ); 
  	}
  
  	for ( j = 0 ; j < chip_count; j++ )
  	{
  	    if ( z2ram_map[ i ] )
  	    {
  		amiga_chip_free( (void *) z2ram_map[ i++ ] );
  	    }
  	}
  
  	if ( z2ram_map != NULL )
  	{
  	    kfree( z2ram_map );
  	}
      }
  
      return;
  } 

  
  module_init(z2_init);
  module_exit(z2_exit);
  MODULE_LICENSE("GPL");