#ifndef _BLK_H
#define _BLK_H

#include <linuxmt/major.h>
#include <linuxmt/sched.h>
#include <linuxmt/kdev_t.h>
/*#include <linuxmt/locks.h>*/
#include <linuxmt/genhd.h>

/*
 * Ok, this is an expanded form so that we can use the same
 * request for paging requests when that is implemented. In
 * paging, 'bh' is NULL, and 'waiting' is used to wait for
 * read/write completion.
 */

struct request {
	kdev_t dev;		/* -1 if no request */
	__u8  cmd;		/* READ or WRITE */
	__u8  errors;
	__u8  rq_status;
	unsigned long sector;
	unsigned long nr_sectors;
	unsigned long current_nr_sectors;
	char * buffer;
	struct task_struct * waiting;
	struct buffer_head * bh, *bhtail;
	struct request * next;
};

#define RQ_INACTIVE	0
#define RQ_ACTIVE	1

/*
 * This is used in the elevator algorithm: Note that
 * reads always go before writes. This is natural: reads
 * are much more time-critical than writes.
 *
 * Update: trying with writes being preferred due to test
 * by Alessandro Rubini..
 */
 
#define IN_ORDER(s1,s2) \
((s1)->cmd > (s2)->cmd || ((s1)->cmd == (s2)->cmd && \
((s1)->dev < (s2)->dev || (((s1)->dev == (s2)->dev && \
(s1)->sector < (s2)->sector)))))

struct blk_dev_struct {
	void (*request_fn)();
	struct request *current_request;
};

#define SECTOR_MASK 2		/* 1024 logical 512 physical */

#define SUBSECTOR(block) (CURRENT->current_nr_sectors > 0)

extern struct blk_dev_struct blk_dev[MAX_BLKDEV];
extern struct wait_queue *wait_for_request;
extern void resetup_one_dev();

extern unsigned long hd_init();
extern int is_read_only();
extern void set_device_ro();

extern void rd_load();
extern long rd_init();

extern unsigned long xd_init();

#ifdef MAJOR_NR

/*
 * Add entries as needed. Currently the only block devices
 * supported are hard-disks and floppies.
 */

#ifdef RAMDISK

/* ram disk */
#define DEVICE_NAME "ramdisk"
#define DEVICE_REQUEST do_rd_request
#define DEVICE_NR(device) ((device) & 7)
#define DEVICE_ON(device) 
#define DEVICE_OFF(device)

#endif
#ifdef FLOPPYDISK

static void floppy_on(); /*(unsigned int nr);*/
static void floppy_off(); /*(unsigned int nr);*/

#define DEVICE_NAME "floppy"
#define DEVICE_INTR do_floppy
#define DEVICE_REQUEST do_fd_request
#define DEVICE_NR(device) ((device) & 3)
#define DEVICE_ON(device) floppy_on(DEVICE_NR(device))
#define DEVICE_OFF(device) floppy_off(DEVICE_NR(device))

#endif
#ifdef ATDISK

/* harddisk: timeout is 6 seconds.. */
#define DEVICE_NAME "harddisk"
#define DEVICE_INTR do_hd
#define DEVICE_TIMEOUT HD_TIMER
#define TIMEOUT_VALUE 600
#define DEVICE_REQUEST do_hd_request
#define DEVICE_NR(device) (MINOR(device)>>6)
#define DEVICE_ON(device)
#define DEVICE_OFF(device)

#endif
#ifdef XTDISK

#define DEVICE_NAME "xt disk"
#define DEVICE_REQUEST do_xd_request
#define DEVICE_NR(device) (MINOR(device) >> 6)
#define DEVICE_ON(device)
#define DEVICE_OFF(device)

#endif

#ifdef BIOSDISK
#define DEVICE_NAME "BIOSHD"
#define DEVICE_REQUEST do_bioshd_request
#define DEVICE_NR(device) (MINOR(device)>>6)
#define DEVICE_ON(device)
#define DEVICE_OFF(device)
#endif

#ifndef CURRENT
#define CURRENT (blk_dev[MAJOR_NR].current_request)
#endif

#define CURRENT_DEV DEVICE_NR(CURRENT->dev)

#ifdef DEVICE_INTR
void (*DEVICE_INTR)() = NULL;
#endif
#ifdef DEVICE_TIMEOUT

#define SET_TIMER \
((timer_table[DEVICE_TIMEOUT].expires = jiffies + TIMEOUT_VALUE), \
(timer_active |= 1<<DEVICE_TIMEOUT))

#define CLEAR_TIMER \
timer_active &= ~(1<<DEVICE_TIMEOUT)

#define SET_INTR(x) \
if ((DEVICE_INTR = (x)) != NULL) \
	SET_TIMER; \
else \
	CLEAR_TIMER;

#else

#define SET_INTR(x) (DEVICE_INTR = (x))

#endif
static void (DEVICE_REQUEST)();

static void end_request(uptodate)
int uptodate;
{
	struct request * req;
	struct buffer_head * bh;
	struct task_struct * p;

	req = CURRENT;
	req->errors = 0;
	if (!uptodate) {
		printk("%s:I/O error\n", DEVICE_NAME);
		printk("dev %x, sector %ld\n",
		       (unsigned long)req->dev, req->sector);
		req->nr_sectors--;
		req->nr_sectors &= ~SECTOR_MASK;
		req->sector += (BLOCK_SIZE / 512);
		req->sector &= ~SECTOR_MASK;		
	}

	if ((bh = req->bh) != NULL) {
		req->bh = bh->b_reqnext;
		bh->b_reqnext = NULL;
		cli();
		bh->b_state &= ~(1<<BH_Uptodate);
		bh->b_state |= (uptodate<<BH_Uptodate);
		sti();
		unlock_buffer(bh);
		if ((bh = req->bh) != NULL) {
			req->current_nr_sectors = bh->b_size >> 9;
			if (req->nr_sectors < req->current_nr_sectors) {
				req->nr_sectors = req->current_nr_sectors;
				printk("end_request: buffer-list destroyed\n");
			}
			req->buffer = bh->b_data;
			return;
		}
	}
	DEVICE_OFF(req->dev);
	CURRENT = req->next;
	if ((p = req->waiting) != NULL) {
		req->waiting = NULL;
		p->state = TASK_RUNNING;
		if (p->counter > current->counter)
			need_resched = 1;
	}
	req->dev = -1;
	wake_up(&wait_for_request);
}
#endif

#ifdef DEVICE_INTR
#define CLEAR_INTR SET_INTR(NULL)
#else
#define CLEAR_INTR
#endif

#define INIT_REQUEST \
	if (!CURRENT) {\
		CLEAR_INTR; \
		return; \
	} \
	if (MAJOR(CURRENT->dev) != MAJOR_NR) \
		panic("%s: request list destroyed", DEVICE_NAME); \
	if (CURRENT->bh) { \
		if (!buffer_locked(CURRENT->bh)) \
			panic("%s:block not locked", DEVICE_NAME); \
	}

#endif