* add p cc

[mascara-docs.git] / i386 / linux / linux-0.99 / drivers / block / xd.c

/*
 * 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 */
};
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 */
static void xd_interrupt_handler (int unused)
{
        if (inb(XD_STATUS) & STAT_INTERRUPT) {                                                  /* check if it was our device */
#ifdef DEBUG_OTHER
                printk("xd_interrupt_handler: interrupt detected\n");
#endif /* DEBUG_OTHER */
                outb(0,XD_CONTROL);                                                             /* acknowledge interrupt */
                wake_up(&xd_wait_int);                                                          /* and wake up sleeping processes */
        }
        else
                printk("xd_interrupt_handler: unexpected interrupt\n");
}

/* xd_dma: set up the DMA controller for a data transfer */
static u_char xd_setup_dma (u_char mode,u_char *buffer,u_int count)
{
        if (buffer < ((u_char *) 0x1000000 - count)) {          /* transfer to address < 16M? */
                if (((u_int) buffer & 0xFFFF0000) != ((u_int) buffer + count) & 0xFFFF0000) {
#ifdef DEBUG_OTHER
                        printk("xd_setup_dma: using PIO, transfer overlaps 64k boundary\n");
#endif /* DEBUG_OTHER */
                        return (PIO_MODE);
                }
                disable_dma(xd_dma);
                clear_dma_ff(xd_dma);
                set_dma_mode(xd_dma,mode);
                set_dma_addr(xd_dma,(u_int) buffer);
                set_dma_count(xd_dma,count);

                return (DMA_MODE);                      /* use DMA and INT */
        }
#ifdef DEBUG_OTHER
        printk("xd_setup_dma: using PIO, cannot DMA above 16 meg\n");
#endif /* DEBUG_OTHER */
        return (PIO_MODE);
}

/* xd_build: put stuff into an array in a format suitable for the controller */
static u_char *xd_build (u_char *cmdblk,u_char command,u_char drive,u_char head,u_short cylinder,u_char sector,u_char count,u_char control)
{
        cmdblk[0] = command;
        cmdblk[1] = ((drive & 0x07) << 5) | (head & 0x1F);
        cmdblk[2] = ((cylinder & 0x300) >> 2) | (sector & 0x3F);
        cmdblk[3] = cylinder & 0xFF;
        cmdblk[4] = count;
        cmdblk[5] = control;
        
        return (cmdblk);
}

/* xd_waitport: waits until port & mask == flags or a timeout occurs. return 1 for a timeout */
static inline u_char xd_waitport (u_short port,u_char flags,u_char mask,u_long timeout)
{
        u_long expiry = jiffies + timeout;

        while (((inb(port) & mask) != flags) && (jiffies < expiry))
                ;

        return (jiffies >= expiry);
}

/* xd_command: handle all data transfers necessary for a single command */
static u_int xd_command (u_char *command,u_char mode,u_char *indata,u_char *outdata,u_char *sense,u_long timeout)
{
        u_char cmdblk[6],csb,complete = 0;

#ifdef DEBUG_COMMAND
        printk("xd_command: command = 0x%X, mode = 0x%X, indata = 0x%X, outdata = 0x%X, sense = 0x%X\n",command,mode,indata,outdata,sense);
#endif /* DEBUG_COMMAND */

        outb(0,XD_SELECT);
        outb(mode,XD_CONTROL);

        if (xd_waitport(XD_STATUS,STAT_SELECT,STAT_SELECT,timeout))
                return (1);
        
        while (!complete) {
                if (xd_waitport(XD_STATUS,STAT_READY,STAT_READY,timeout))
                        return (1);
                switch (inb(XD_STATUS) & (STAT_COMMAND | STAT_INPUT)) {
                        case 0:                 if (mode == DMA_MODE) {
                                                        enable_dma(xd_dma);
                                                        sleep_on(&xd_wait_int);
                                                        disable_dma(xd_dma);
                                                }
                                                else
                                                        outb(outdata ? *outdata++ : 0,XD_DATA);
                                                break;
                        case STAT_INPUT:        if (mode == DMA_MODE) {
                                                        enable_dma(xd_dma);
                                                        sleep_on(&xd_wait_int);
                                                        disable_dma(xd_dma);
                                                }
                                                else
                                                        if (indata)
                                                                *indata++ = inb(XD_DATA);
                                                        else
                                                                inb(XD_DATA);
                                                break;
                        case STAT_COMMAND:      outb(command ? *command++ : 0,XD_DATA); break;
                        case STAT_COMMAND
                             | STAT_INPUT:      complete = 1; break;
                }
        }
        csb = inb(XD_DATA);

        if (xd_waitport(XD_STATUS,0,STAT_SELECT,timeout))                                       /* wait until deselected */
                return (1);

        if (csb & CSB_ERROR) {                                                                  /* read sense data if error */
                xd_build(cmdblk,CMD_SENSE,(csb & CSB_LUN) >> 5,0,0,0,0,0);
                if (xd_command(cmdblk,0,sense,0,0,XD_TIMEOUT))
                        printk("xd_command: warning! sense command failed!\n");
        }

#ifdef DEBUG_COMMAND
        printk("xd_command: completed with csb = 0x%X\n",csb);
#endif /* DEBUG_COMMAND */

        return (csb & CSB_ERROR);
}

static u_char xd_initdrives (void (*init_drive)(u_char drive))
{
        u_char cmdblk[6],i,count = 0;

        for (i = 0; i < XD_MAXDRIVES; i++) {
                xd_build(cmdblk,CMD_TESTREADY,i,0,0,0,0,0);
                if (!xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 2)) {
                        init_drive(count);
                        count++;
                }
        }
        return (count);
}

static void xd_dtc_init_controller (u_char *address)
{
        switch ((u_long) address) {
                case 0xC8000:   xd_iobase = 0x320; break;
                case 0xCA000:   xd_iobase = 0x324; break;
                default:        printk("xd_dtc_init_controller: unsupported BIOS address %p\n",address);
                                xd_iobase = 0x320; break;
        }
        xd_irq = 5;                     /* the IRQ _can_ be changed on this card, but requires a hardware mod */
        xd_dma = 3;
        xd_maxsectors = 0x01;           /* my card seems to have trouble doing multi-block transfers? */

        outb(0,XD_RESET);               /* reset the controller */
}

static void xd_dtc_init_drive (u_char drive)
{
        u_char cmdblk[6],buf[64];

        xd_build(cmdblk,CMD_DTCGETGEOM,drive,0,0,0,0,0);
        if (!xd_command(cmdblk,PIO_MODE,buf,0,0,XD_TIMEOUT * 2)) {
                xd_info[drive].heads = buf[0x0A];                       /* heads */
                xd_info[drive].cylinders = ((u_short *) (buf))[0x04];   /* cylinders */
                xd_info[drive].sectors = 17;                            /* sectors */
#if 0
                xd_info[drive].rwrite = ((u_short *) (buf + 1))[0x05];  /* reduced write */
                xd_info[drive].precomp = ((u_short *) (buf + 1))[0x06]; /* write precomp */
                xd_info[drive].ecc = buf[0x0F];                         /* ecc length */
#endif /* 0 */
                xd_info[drive].control = 0;                             /* control byte */

                xd_setparam(CMD_DTCSETPARAM,drive,xd_info[drive].heads,xd_info[drive].cylinders,((u_short *) (buf + 1))[0x05],((u_short *) (buf + 1))[0x06],buf[0x0F]);
                xd_build(cmdblk,CMD_DTCSETSTEP,drive,0,0,0,0,7);
                if (xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 2))
                        printk("xd_dtc_init_drive: error setting step rate for drive %d\n",drive);
        }
        else
                printk("xd_dtc_init_drive: error reading geometry for drive %d\n",drive);
}

static void xd_wd_init_controller (u_char *address)
{
        switch ((u_long) address) {
                case 0xC8000:   xd_iobase = 0x320; break;
                case 0xCA000:   xd_iobase = 0x324; break;
                case 0xCC000:   xd_iobase = 0x328; break;
                case 0xCE000:   xd_iobase = 0x32C; break;
                case 0xD0000:   xd_iobase = 0x328; break;
                case 0xD8000:   xd_iobase = 0x32C; break;
                default:        printk("xd_wd_init_controller: unsupported BIOS address %p\n",address);
                                xd_iobase = 0x320; break;
        }
        xd_irq = 5;                     /* don't know how to auto-detect this yet */
        xd_dma = 3;
        xd_maxsectors = 0x01;           /* this one doesn't wrap properly either... */

        /* outb(0,XD_RESET); */         /* reset the controller */
}

static void xd_wd_init_drive (u_char drive)
{
        u_char cmdblk[6],buf[0x200];

        xd_build(cmdblk,CMD_READ,drive,0,0,0,1,0);
        if (!xd_command(cmdblk,PIO_MODE,buf,0,0,XD_TIMEOUT * 2)) {
                xd_info[drive].heads = buf[0x1AF];                              /* heads */
                xd_info[drive].cylinders = ((u_short *) (buf + 1))[0xD6];       /* cylinders */
                xd_info[drive].sectors = 17;                                    /* sectors */
#if 0
                xd_info[drive].rwrite = ((u_short *) (buf))[0xD8];              /* reduced write */
                xd_info[drive].wprecomp = ((u_short *) (buf))[0xDA];            /* write precomp */
                xd_info[drive].ecc = buf[0x1B4];                                /* ecc length */
#endif /* 0 */
                xd_info[drive].control = buf[0x1B5];                            /* control byte */

                xd_setparam(CMD_WDSETPARAM,drive,xd_info[drive].heads,xd_info[drive].cylinders,((u_short *) (buf))[0xD8],((u_short *) (buf))[0xDA],buf[0x1B4]);
        }
        else
                printk("xd_wd_init_drive: error reading geometry for drive %d\n",drive);        
}

static void xd_seagate_init_controller (u_char *address)
{
        switch ((u_long) address) {
                case 0xC8000:   xd_iobase = 0x320; break;
                case 0xD0000:   xd_iobase = 0x324; break;
                case 0xD8000:   xd_iobase = 0x328; break;
                case 0xE0000:   xd_iobase = 0x32C; break;
                default:        printk("xd_seagate_init_controller: unsupported BIOS address %p\n",address);
                                xd_iobase = 0x320; break;
        }
        xd_irq = 5;                     /* the IRQ and DMA channel are fixed on the Seagate controllers */
        xd_dma = 3;
        xd_maxsectors = 0x40;

        outb(0,XD_RESET);               /* reset the controller */
}

static void xd_seagate_init_drive (u_char drive)
{
        u_char cmdblk[6],buf[0x200];

        xd_build(cmdblk,CMD_ST11GETGEOM,drive,0,0,0,1,0);
        if (!xd_command(cmdblk,PIO_MODE,buf,0,0,XD_TIMEOUT * 2)) {
                xd_info[drive].heads = buf[0x04];                               /* heads */
                xd_info[drive].cylinders = (buf[0x02] << 8) | buf[0x03];        /* cylinders */
                xd_info[drive].sectors = buf[0x05];                             /* sectors */
                xd_info[drive].control = 0;                                     /* control byte */
        }
        else
                printk("xd_seagate_init_drive: error reading geometry from drive %d\n",drive);
}

/* xd_override_init_drive: this finds disk geometry in a "binary search" style, narrowing in on the "correct" number of heads
   etc. by trying values until it gets the highest successful value. Idea courtesy Salvador Abreu (spa@fct.unl.pt). */
static void xd_override_init_drive (u_char drive)
{
        u_short min[] = { 0,0,0 },max[] = { 16,1024,64 },test[] = { 0,0,0 };
        u_char cmdblk[6],i;

        for (i = 0; i < 3; i++) {
                while (min[i] != max[i] - 1) {
                        test[i] = (min[i] + max[i]) / 2;
                        xd_build(cmdblk,CMD_SEEK,drive,(u_char) test[0],(u_short) test[1],(u_char) test[2],0,0);
                        if (!xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 2))
                                min[i] = test[i];
                        else
                                max[i] = test[i];
                }
                test[i] = min[i];
        }
        xd_info[drive].heads = (u_char) min[0] + 1;
        xd_info[drive].cylinders = (u_short) min[1] + 1;
        xd_info[drive].sectors = (u_char) min[2] + 1;
        xd_info[drive].control = 0;
}

/* xd_setup: initialise from command line parameters */
void xd_setup (char *command,int *integers)
{
        xd_override = 1;

        xd_type = integers[1];
        xd_irq = integers[2];
        xd_iobase = integers[3];
        xd_dma = integers[4];

        xd_maxsectors = 0x01;
}

/* xd_setparam: set the drive characteristics */
static void xd_setparam (u_char command,u_char drive,u_char heads,u_short cylinders,u_short rwrite,u_short wprecomp,u_char ecc)
{
        u_char cmdblk[14];

        xd_build(cmdblk,command,drive,0,0,0,0,0);
        cmdblk[6] = (u_char) (cylinders >> 8) & 0x03;
        cmdblk[7] = (u_char) (cylinders & 0xFF);
        cmdblk[8] = heads & 0x1F;
        cmdblk[9] = (u_char) (rwrite >> 8) & 0x03;
        cmdblk[10] = (u_char) (rwrite & 0xFF);
        cmdblk[11] = (u_char) (wprecomp >> 8) & 0x03;
        cmdblk[12] = (u_char) (wprecomp & 0xFF);
        cmdblk[13] = ecc;

        if (xd_command(cmdblk,PIO_MODE,0,0,0,XD_TIMEOUT * 2))
                printk("xd_setparam: error setting characteristics for drive %d\n",drive);
}