/*
 * This file contains the driver for an XT hard disk controller (at least the DTC 5150X) for Linux.
 *
 * Author: Pat Mackinlay, smackinla@cc.curtin.edu.au
 * Date: 29/09/92
 * 
 * Revised: 01/01/93, ...
 *
 * Ref: DTC 5150X Controller Specification (thanks to Kevin Fowler, kevinf@agora.rain.com)
 * Also thanks to: Salvador Abreu, Dave Thaler, Risto Kankkunen and Wim Van Dorst.
 */


#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/genhd.h>
#include <linux/xd.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/dma.h>

#define MAJOR_NR XT_DISK_MAJOR
#include "blk.h"

XD_INFO xd_info[XD_MAXDRIVES];

/* If you try this driver and find that your card is not detected by the driver at bootup, you need to add your BIOS
   signature and details to the following list of signatures. A BIOS signature is a string embedded into the first
   few bytes of your controller's on-board ROM BIOS. To find out what yours is, use something like MS-DOS's DEBUG
   command. Run DEBUG, and then you can examine your BIOS signature with:

	d xxxx:0000

   where xxxx is the segment of your controller (like C800 or D000 or something). On the ASCII dump at the right, you should
   be able to see a string mentioning the manufacturer's copyright etc. Add this string into the table below. The parameters
   in the table are, in order:

	offset			; this is the offset (in bytes) from the start of your ROM where the signature starts
	signature		; this is the actual text of the signature
	xd_?_init_controller	; this is the controller init routine used by your controller
	xd_?_init_drive		; this is the drive init routine used by your controller

   The controllers directly supported at the moment are: DTC 5150x, WD 1004A27X, ST11M/R and override. If your controller is
   made by the same manufacturer as one of these, try using the same init routines as they do. If that doesn't work, your
   best bet is to use the "override" routines. These routines use a "portable" method of getting the disk's geometry, and
   may work with your card. If none of these seem to work, try sending me some email and I'll see what I can do <grin>.

   NOTE: You can now specify your XT controller's parameters from the command line in the form xd=TYPE,IRQ,IO,DMA. The driver
   should be able to detect your drive's geometry from this info. (eg: xd=0,5,0x320,3 is the "standard"). */

static XD_SIGNATURE xd_sigs[] = {
	{ 0x0000,"Override geometry handler",NULL,xd_override_init_drive,"n unknown" }, /* Pat Mackinlay, smackinla@cc.curtin.edu.au (pat@gu.uwa.edu.au) */
	{ 0x000B,"CXD23A Not an IBM ROM (C)Copyright Data Technology Corp 12/03/88",xd_dtc_init_controller,xd_dtc_init_drive," DTC 5150X" }, /* Pat Mackinlay, smackinla@cc.curtin.edu.au (pat@gu.uwa.edu.au) */
	{ 0x0008,"07/15/86 (C) Copyright 1986 Western Digital Corp",xd_wd_init_controller,xd_wd_init_drive," Western Digital 1002AWX1" }, /* Ian Justman, citrus!ianj@csusac.ecs.csus.edu */
	{ 0x0008,"06/24/88 (C) Copyright 1988 Western Digital Corp",xd_wd_init_controller,xd_wd_init_drive," Western Digital 1004A27X" }, /* Dave Thaler, thalerd@engin.umich.edu */
	{ 0x0008,"06/24/88(C) Copyright 1988 Western Digital Corp.",xd_wd_init_controller,xd_wd_init_drive," Western Digital WDXT-GEN2" }, /* Dan Newcombe, newcombe@aa.csc.peachnet.edu */
	{ 0x0015,"SEAGATE ST11 BIOS REVISION",xd_seagate_init_controller,xd_seagate_init_drive," Seagate ST11M/R" }, /* Salvador Abreu, spa@fct.unl.pt */
	{ 0x0010,"ST11R BIOS",xd_seagate_init_controller,xd_seagate_init_drive," Seagate ST11M/R" }, /* Risto Kankkunen, risto.kankkunen@cs.helsinki.fi */
	{ 0x1000,"(c)Copyright 1987 SMS",xd_omti_init_controller,xd_omti_init_drive,"n OMTI 5520" }, /* Dirk Melchers, dirk@merlin.nbg.sub.org */
};
static u_char *xd_bases[] =
{
	(u_char *) 0xC8000,(u_char *) 0xCA000,(u_char *) 0xCC000,
	(u_char *) 0xCE000,(u_char *) 0xD0000,(u_char *) 0xD8000,
	(u_char *) 0xE0000
};

static struct hd_struct xd[XD_MAXDRIVES << 6];
static int xd_sizes[XD_MAXDRIVES << 6],xd_access[XD_MAXDRIVES] = { 0,0 };
static int xd_blocksizes[XD_MAXDRIVES << 6];
static struct gendisk xd_gendisk = { MAJOR_NR,"xd",6,1 << 6,XD_MAXDRIVES,xd_geninit,xd,xd_sizes,0,(void *) xd_info,NULL };
static struct file_operations xd_fops = { NULL,block_read,block_write,NULL,NULL,xd_ioctl,NULL,xd_open,xd_release,block_fsync };

static struct wait_queue *xd_wait_int = NULL,*xd_wait_open = NULL;
static u_char xd_valid[XD_MAXDRIVES] = { 0,0 };
static u_char xd_drives = 0,xd_irq = 0,xd_dma = 0,xd_maxsectors,xd_override = 0,xd_type = 0;
static u_short xd_iobase = 0;

/* xd_init: grab the IRQ and DMA channel and initialise the drives */
u_long xd_init (u_long mem_start,u_long mem_end)
{
	u_char i,controller,*address;
	
	if (register_blkdev(MAJOR_NR,"xd",&xd_fops)) {
		printk("xd_init: unable to get major number %d\n",MAJOR_NR);
		return (mem_start);
	}
	blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
	read_ahead[MAJOR_NR] = 8;	/* 8 sector (4kB) read ahead */
	xd_gendisk.next = gendisk_head;
	gendisk_head = &xd_gendisk;

	if (xd_detect(&controller,&address)) {

		printk("xd_init: detected a%s controller (type %d) at address %p\n",xd_sigs[controller].name,controller,address);
		if (controller)
			xd_sigs[controller].init_controller(address);
		xd_drives = xd_initdrives(xd_sigs[controller].init_drive);
		
		printk("xd_init: detected %d hard drive%s (using IRQ%d & DMA%d)\n",xd_drives,xd_drives == 1 ? "" : "s",xd_irq,xd_dma);
		for (i = 0; i < xd_drives; i++)
			printk("xd_init: drive %d geometry - heads = %d, cylinders = %d, sectors = %d\n",i,xd_info[i].heads,xd_info[i].cylinders,xd_info[i].sectors);

		if (!request_irq(xd_irq,xd_interrupt_handler)) {
			if (request_dma(xd_dma)) {
				printk("xd_init: unable to get DMA%d\n",xd_dma);
				free_irq(xd_irq);
			}
		}
		else
			printk("xd_init: unable to get IRQ%d\n",xd_irq);
	}
	return mem_start;
}

/* xd_detect: scan the possible BIOS ROM locations for the signature strings */
static u_char xd_detect (u_char *controller,u_char **address)
{
	u_char i,j,found = 0;

	if (xd_override)
	{
		*controller = xd_type;
		*address = NULL;
		return(1);
	}

	for (i = 0; i < (sizeof(xd_bases) / sizeof(xd_bases[0])) && !found; i++)
		for (j = 1; j < (sizeof(xd_sigs) / sizeof(xd_sigs[0])) && !found; j++)
			if (!memcmp(xd_bases[i] + xd_sigs[j].offset,xd_sigs[j].string,strlen(xd_sigs[j].string))) {
				*controller = j;
				*address = xd_bases[i];
				found++;
			}
	return (found);
}

/* xd_geninit: set up the "raw" device entries in the table */
static void xd_geninit (void)
{
	u_char i;

	for (i = 0; i < xd_drives; i++) {
		xd[i << 6].nr_sects = xd_info[i].heads * xd_info[i].cylinders * xd_info[i].sectors;
		xd_valid[i] = 1;
	}

	xd_gendisk.nr_real = xd_drives;

	for(i=0;i<(XD_MAXDRIVES << 6);i++) xd_blocksizes[i] = 1024;
	blksize_size[MAJOR_NR] = xd_blocksizes;
}

/* xd_open: open a device */
static int xd_open (struct inode *inode,struct file *file)
{
	int dev = DEVICE_NR(MINOR(inode->i_rdev));

	if (dev < xd_drives) {
		while (!xd_valid[dev])
			sleep_on(&xd_wait_open);

		xd_access[dev]++;

		return (0);
	}
	else
		return (-ENODEV);
}

/* do_xd_request: handle an incoming request */
static void do_xd_request (void)
{
	u_int block,count,retry;
	int code;

	sti();
	while (code = 0, CURRENT) {
		INIT_REQUEST;	/* do some checking on the request structure */

		if (CURRENT_DEV < xd_drives && CURRENT->sector + CURRENT->nr_sectors <= xd[MINOR(CURRENT->dev)].nr_sects) {
			block = CURRENT->sector + xd[MINOR(CURRENT->dev)].start_sect;
			count = CURRENT->nr_sectors;

			switch (CURRENT->cmd) {
				case READ:
				case WRITE:	for (retry = 0; (retry < XD_RETRIES) && !code; retry++)
							code = xd_readwrite(CURRENT->cmd,CURRENT_DEV,CURRENT->buffer,block,count);
						break;
				default:	printk("do_xd_request: unknown request\n"); break;
			}
		}
		end_request(code);	/* wrap up, 0 = fail, 1 = success */
	}
}

/* xd_ioctl: handle device ioctl's */
static int xd_ioctl (struct inode *inode,struct file *file,u_int cmd,u_long arg)
{
	XD_GEOMETRY *geometry = (XD_GEOMETRY *) arg;
	int dev = DEVICE_NR(MINOR(inode->i_rdev)),err;

	if (inode && (dev < xd_drives))
		switch (cmd) {
			case HDIO_GETGEO:	if (arg) {
							if ((err = verify_area(VERIFY_WRITE,geometry,sizeof(*geometry))))
								return (err);
							put_fs_byte(xd_info[dev].heads,(char *) &geometry->heads);
							put_fs_byte(xd_info[dev].sectors,(char *) &geometry->sectors);
							put_fs_word(xd_info[dev].cylinders,(short *) &geometry->cylinders);
							put_fs_long(xd[MINOR(inode->i_rdev)].start_sect,(long *) &geometry->start);

							return (0);
						}
						break;
			case BLKGETSIZE:	if (arg) {
							if ((err = verify_area(VERIFY_WRITE,(long *) arg,sizeof(long))))
								return (err);
							put_fs_long(xd[MINOR(inode->i_rdev)].nr_sects,(long *) arg);

							return (0);
						}
						break;
			case BLKFLSBUF:
				if(!suser())  return -EACCES;
				if(!inode->i_rdev) return -EINVAL;
				fsync_dev(inode->i_rdev);
				invalidate_buffers(inode->i_rdev);
				return 0;
				
			case BLKRRPART:		return (xd_reread_partitions(inode->i_rdev));
			RO_IOCTLS(inode->i_rdev,arg);
		}
	return (-EINVAL);
}

/* xd_release: release the device */
static void xd_release (struct inode *inode, struct file *file)
{
	int dev = DEVICE_NR(MINOR(inode->i_rdev));

	if (dev < xd_drives) {
		sync_dev(dev);
		xd_access[dev]--;
	}
}

/* xd_reread_partitions: rereads the partition table from a drive */
static int xd_reread_partitions(int dev)
{
	int target = DEVICE_NR(MINOR(dev)),start = target << xd_gendisk.minor_shift,partition;

	cli(); xd_valid[target] = (xd_access[target] != 1); sti();
	if (xd_valid[target])
		return (-EBUSY);

	for (partition = xd_gendisk.max_p - 1; partition >= 0; partition--) {
		sync_dev(MAJOR_NR << 8 | start | partition);
		invalidate_inodes(MAJOR_NR << 8 | start | partition);
		invalidate_buffers(MAJOR_NR << 8 | start | partition);
		xd_gendisk.part[start + partition].start_sect = 0;
		xd_gendisk.part[start + partition].nr_sects = 0;
	};

	xd_gendisk.part[start].nr_sects = xd_info[target].heads * xd_info[target].cylinders * xd_info[target].sectors;
	resetup_one_dev(&xd_gendisk,target);

	xd_valid[target] = 1;
	wake_up(&xd_wait_open);

	return (0);
}

/* xd_readwrite: handle a read/write request */
static int xd_readwrite (u_char operation,u_char drive,char *buffer,u_int block,u_int count)
{
	u_char cmdblk[6],sense[4];
	u_short track,cylinder;
	u_char head,sector,control,mode,temp;
	
#ifdef DEBUG_READWRITE
	printk("xd_readwrite: operation = %s, drive = %d, buffer = 0x%X, block = %d, count = %d\n",operation == READ ? "read" : "write",drive,buffer,block,count);
#endif /* DEBUG_READWRITE */

	control = xd_info[drive].control;
	while (count) {
		temp = count < xd_maxsectors ? count : xd_maxsectors;

		track = block / xd_info[drive].sectors;
		head = track % xd_info[drive].heads;
		cylinder = track / xd_info[drive].heads;
		sector = block % xd_info[drive].sectors;

#ifdef DEBUG_READWRITE
		printk("xd_readwrite: drive = %d, head = %d, cylinder = %d, sector = %d, count = %d\n",drive,head,cylinder,sector,temp);
#endif /* DEBUG_READWRITE */

		mode = xd_setup_dma(operation == READ ? DMA_MODE_READ : DMA_MODE_WRITE,(u_char *)buffer,temp * 0x200);
		xd_build(cmdblk,operation == READ ? CMD_READ : CMD_WRITE,drive,head,cylinder,sector,temp & 0xFF,control);

		switch (xd_command(cmdblk,mode,(u_char *) buffer,(u_char *) buffer,sense,XD_TIMEOUT)) {
			case 1: printk("xd_readwrite: timeout, recalibrating drive\n"); xd_recalibrate(drive); return (0);
			case 2: switch ((sense[0] & 0x30) >> 4) {
					case 0: printk("xd_readwrite: drive error, code = 0x%X",sense[0] & 0x0F); break;
					case 1: printk("xd_readwrite: controller error, code = 0x%X",sense[0] & 0x0F); break;
					case 2: printk("xd_readwrite: command error, code = 0x%X",sense[0] & 0x0F); break;
					case 3: printk("xd_readwrite: miscellaneous error, code = 0x%X",sense[0] & 0x0F); break;
				}
				if (sense[0] & 0x80)
					printk(" - drive = %d, head = %d, cylinder = %d, sector = %d\n",sense[1] & 0xE0,sense[1] & 0x1F,((sense[2] & 0xC0) << 2) | sense[3],sense[2] & 0x3F);
				else
					printk(" - no valid disk address\n");
				return (0);
		}
		count -= temp, buffer += temp * 0x200, block += temp;
	}
	return (1);
}

/* xd_recalibrate: recalibrate a given drive and reset controller if necessary */
static void xd_recalibrate (u_char drive)
{
	u_char cmdblk[6];
	
	xd_build(cmdblk,CMD_RECALIBRATE,drive,0,0,0,0,0);
	if (xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 8))
		printk("xd_recalibrate: warning! error recalibrating, controller may be unstable\n");
}

/* xd_interrupt_handler: interrupt service routine */