/*
** 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/blk-mq.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/pgtable.h>

#include <asm/setup.h>
#include <asm/amigahw.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 blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
				const struct blk_mq_queue_data *bd)
{
	struct request *req = bd->rq;
	unsigned long start = blk_rq_pos(req) << 9;
	unsigned long len  = blk_rq_cur_bytes(req);

	blk_mq_start_request(req);

	if (start + len > z2ram_size) {
		pr_err(DEVICE_NAME ": bad access: block=%llu, "
		       "count=%u\n",
		       (unsigned long long)blk_rq_pos(req),
		       blk_rq_cur_sectors(req));
		return BLK_STS_IOERR;
	}

	spin_lock_irq(&z2ram_lock);

	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;
	}

	spin_unlock_irq(&z2ram_lock);
	blk_mq_end_request(req, BLK_STS_OK);
	return BLK_STS_OK;
}

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\n" );
		        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_wt(paddr, size);

#else
		vaddr = (unsigned long)z_remap_nocache_nonser(paddr, size);
#endif
		z2ram_map = 
			kmalloc_array(size / Z2RAM_CHUNKSIZE,
                                      sizeof(z2ram_map[0]),
                                      GFP_KERNEL);
		if ( z2ram_map == NULL )
		{
		    printk( KERN_ERR DEVICE_NAME
			": cannot get mem for z2ram_map\n" );
		    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\n",
			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\n" );
		    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)\n",
			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\n" );
		    goto err_out;
		}

		get_z2ram();

		if ( z2ram_size != 0 )
		    printk( KERN_INFO DEVICE_NAME 
			": using %iK of Zorro II RAM\n",
			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\n" );
		    goto err_out;
		}

		get_chipram();

		if ( z2ram_size != 0 )
		    printk( KERN_INFO DEVICE_NAME 
			": using %iK Chip RAM\n",
			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\n" );
	    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_and_module(z2ram_gendisk);
}

static struct request_queue *z2_queue;
static struct blk_mq_tag_set tag_set;

static const struct blk_mq_ops z2_mq_ops = {
	.queue_rq	= z2_queue_rq,
};

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_mq_init_sq_queue(&tag_set, &z2_mq_ops, 16,
					BLK_MQ_F_SHOULD_MERGE);
    if (IS_ERR(z2_queue)) {
	ret = PTR_ERR(z2_queue);
	z2_queue = NULL;
	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);
    blk_mq_free_tag_set(&tag_set);

    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");