/*-
 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
 * Copyright (c) 2001 John H. Baldwin <jhb@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/boot/i386/libi386/bioscd.c,v 1.5 2003/08/25 23:28:31 obrien Exp $
 * $DragonFly: src/sys/boot/pc32/libi386/bioscd.c,v 1.6 2006/09/10 01:26:31 dillon Exp $
 */
/*
 * BIOS CD device handling for CD's that have been booted off of via no
 * emulation booting as defined in the El Torito standard.
 * 
 * Ideas and algorithms from:
 *
 * - FreeBSD libi386/biosdisk.c
 *
 */

#include <stand.h>

#include <sys/param.h>
#include <machine/bootinfo.h>
#include <machine/psl.h>

#include <stdarg.h>

#include <bootstrap.h>
#include <btxv86.h>
#include "libi386.h"

#define BIOSCD_SECSIZE          2048
#define BUFSIZE                 (1 * BIOSCD_SECSIZE)
#define MAXBCDEV                1

/* Major numbers for devices we frontend for. */
#define ACDMAJOR                117
#define CDMAJOR                 15

#ifdef DISK_DEBUG
# define DEBUG(fmt, args...)    printf("%s: " fmt "\n" , __func__ , ## args)
#else
# define DEBUG(fmt, args...)
#endif

struct specification_packet {
        u_char  sp_size;
        u_char  sp_bootmedia;
        u_char  sp_drive;
        u_char  sp_controller;
        u_int   sp_lba;
        u_short sp_devicespec;
        u_short sp_buffersegment;
        u_short sp_loadsegment;
        u_short sp_sectorcount;
        u_short sp_cylsec;
        u_char  sp_head;
};

/*
 * List of BIOS devices, translation from disk unit number to
 * BIOS unit number.
 */
static struct bcinfo {
        int     bc_unit;                /* BIOS unit number */
        struct specification_packet bc_sp;
} bcinfo [MAXBCDEV];
static int nbcinfo = 0;

static int      bc_read(int unit, daddr_t dblk, int blks, caddr_t dest);
static int      bc_init(void);
static int      bc_strategy(void *devdata, int flag, daddr_t dblk,
                    size_t size, char *buf, size_t *rsize);
static int      bc_open(struct open_file *f, ...);
static int      bc_close(struct open_file *f);
static void     bc_print(int verbose);

struct devsw bioscd = {
        "cd", 
        DEVT_CD, 
        bc_init,
        bc_strategy, 
        bc_open, 
        bc_close, 
        noioctl,
        bc_print,
        NULL
};

/*
 * Translate between BIOS device numbers and our private unit numbers.
 */
int
bc_bios2unit(int biosdev)
{
        int i;
    
        DEBUG("looking for bios device 0x%x", biosdev);
        for (i = 0; i < nbcinfo; i++) {
                DEBUG("bc unit %d is BIOS device 0x%x", i, bcinfo[i].bc_unit);
                if (bcinfo[i].bc_unit == biosdev)
                        return(i);
        }
        return(-1);
}

int
bc_unit2bios(int unit)
{
        if ((unit >= 0) && (unit < nbcinfo))
                return(bcinfo[unit].bc_unit);
        return(-1);
}

/*    
 * We can't quiz, we have to be told what device to use, so this functoin
 * doesn't do anything.  Instead, the loader calls bc_add() with the BIOS
 * device number to add.
 */
static int
bc_init(void) 
{

        return (0);
}

int
bc_add(int biosdev)
{

        if (nbcinfo >= MAXBCDEV)
                return (-1);
        bcinfo[nbcinfo].bc_unit = biosdev;
        v86.ctl = V86_FLAGS;
        v86.addr = 0x13;
        v86.eax = 0x4b01;
        v86.edx = biosdev;
        v86.ds = VTOPSEG(&bcinfo[nbcinfo].bc_sp);
        v86.esi = VTOPOFF(&bcinfo[nbcinfo].bc_sp);
        v86int();
        if ((v86.eax & 0xff00) != 0)
                return (-1);

        printf("BIOS CD is cd%d\n", nbcinfo);
        nbcinfo++;
        return(0);
}

/*
 * Print information about disks
 */
static void
bc_print(int verbose)
{
        int i;
        char line[80];
    
        for (i = 0; i < nbcinfo; i++) {
                sprintf(line, "    cd%d: Device 0x%x\n", i,
                    bcinfo[i].bc_sp.sp_devicespec);
                pager_output(line);
        }
}

/*
 * Attempt to open the disk described by (dev) for use by (f).
 */
static int 
bc_open(struct open_file *f, ...)
{
        va_list ap;
        struct i386_devdesc *dev;

        va_start(ap, f);
        dev = va_arg(ap, struct i386_devdesc *);
        va_end(ap);
        if (dev->d_kind.bioscd.unit >= nbcinfo) {
                DEBUG("attempt to open nonexistent disk");
                return(ENXIO);
        }

        return(0);
}
 
static int 
bc_close(struct open_file *f)
{

        return(0);
}

static int 
bc_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf,
    size_t *rsize)
{
        struct i386_devdesc *dev;
        int unit;
        int blks;
#ifdef BD_SUPPORT_FRAGS
#error "xxx broken code xxx"
        char fragbuf[BIOSCD_SECSIZE];
        size_t fragsize;

        fragsize = size % BIOSCD_SECSIZE;
#else
        if (size % BIOSCD_SECSIZE)
                return (EINVAL);
#endif

        if (rw != F_READ)
                return(EROFS);
        dev = (struct i386_devdesc *)devdata;
        unit = dev->d_kind.bioscd.unit;
        blks = size / BIOSCD_SECSIZE;
        if (dblk % (BIOSCD_SECSIZE / DEV_BSIZE) != 0)
                return (EINVAL);
        dblk /= (BIOSCD_SECSIZE / DEV_BSIZE);
        DEBUG("read %d from %d to %p", blks, dblk, buf);

        if (rsize)
                *rsize = 0;
        if (blks && bc_read(unit, dblk, blks, buf)) {
                DEBUG("read error");
                return (EIO);
        }
#ifdef BD_SUPPORT_FRAGS
        DEBUG("bc_strategy: frag read %d from %d+%d to %p", 
            fragsize, dblk, blks, buf + (blks * BIOSCD_SECSIZE));
        if (fragsize && bc_read(unit, dblk + blks, 1, fragsize)) {
                DEBUG("frag read error");
                return(EIO);
        }
        bcopy(fragbuf, buf + (blks * BIOSCD_SECSIZE), fragsize);
#endif  
        if (rsize)
                *rsize = size;
        return (0);
}

static int
bc_read(int unit, daddr_t dblk, int blks, caddr_t dest)
{
        u_int result, retry;
        static unsigned short packet[8];
        int biosdev;
        int n;
#ifdef DISK_DEBUG
        int error;
#endif
    
        /* Just in case some idiot actually tries to read -1 blocks... */
        if (blks < 0)
                return (-1);

        /* If nothing to do, just return succcess. */
        if (blks == 0)
                return (0);

        biosdev = bc_unit2bios(unit);
        /*
         * Loop retrying the operation a couple of times.  The BIOS
         * may also retry.
         */
        for (retry = 0; retry < 3; retry++) {
                /* If retrying, reset the drive */
                if (retry > 0) {
                        v86.ctl = V86_FLAGS;
                        v86.addr = 0x13;
                        v86.eax = 0;
                        v86.edx = biosdev;
                        v86int();
                }

                n = BOUNCEBUF_SIZE / BIOSCD_SECSIZE;
                if (n > blks)
                        n = blks;
            
                packet[0] = 0x10;
                packet[1] = n;
                packet[2] = VTOPOFF(bounce_base);
                packet[3] = VTOPSEG(bounce_base);
                packet[4] = dblk & 0xffff;
                packet[5] = dblk >> 16;
                packet[6] = 0;
                packet[7] = 0;
                v86.ctl = V86_FLAGS;
                v86.addr = 0x13;
                v86.eax = 0x4200;
                v86.edx = biosdev;
                v86.ds = VTOPSEG(packet);
                v86.esi = VTOPOFF(packet);
                v86int();
                result = (v86.efl & PSL_C);
                if (result == 0) {
                        bcopy(bounce_base, dest, n * BIOSCD_SECSIZE);
                        blks -= n;
                        dest += n * BIOSCD_SECSIZE;
                        if (blks == 0)
                                break;
                        retry = 0;
                }
        }
        
#ifdef DISK_DEBUG
        error = (v86.eax >> 8) & 0xff;
#endif
        DEBUG("%d sectors from %ld to %p (0x%x) %s", blks, dblk, dest,
            VTOP(dest), result ? "failed" : "ok");
        DEBUG("unit %d  status 0x%x",  unit, error);
        
/*      hexdump(dest, (blks * BIOSCD_SECSIZE)); */
        return(0);
}

/*
 * Return a suitable cdev_t value for (dev).
 */
int
bc_getdev(struct i386_devdesc *dev)
{
    int biosdev, unit;
    int major;
    int rootdev;

    unit = dev->d_kind.bioscd.unit;
    biosdev = bc_unit2bios(unit);
    DEBUG("unit %d BIOS device %d", unit, biosdev);
    if (biosdev == -1)                          /* not a BIOS device */
        return(-1);

    /*
     * XXX: Need to examine device spec here to figure out if SCSI or
     * ATAPI.  No idea on how to figure out device number.  All we can
     * really pass to the kernel is what bus and device on which bus we
     * were booted from, which cdev_t isn't well suited to since those
     * number don't match to unit numbers very well.  We may just need
     * to engage in a hack where we pass -C to the boot args if we are
     * the boot device.
     */
    major = ACDMAJOR;
    unit = 0;   /* XXX */

    /* XXX: Assume partition 'a'. */
    rootdev = MAKEBOOTDEV(major, 0, unit, 0);
    DEBUG("dev is 0x%x\n", rootdev);
    return(rootdev);
}