/**

 * $Id: linux.c,v 1.4 2007-02-11 10:11:05 nkeynes Exp $

 *

 * Linux cd-rom device driver. 

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include <linux/cdrom.h>

#include <sys/stat.h>

#include <sys/ioctl.h>

#include "gdrom/gdrom.h"

#include "gdrom/packet.h"

#include "dream.h"

#define MAXTOCENTRIES 600  /* This is a fairly generous overestimate really */

#define MAXTOCSIZE 4 + (MAXTOCENTRIES*11)

#define MAX_SECTORS_PER_CALL 1

#define MSFTOLBA( m,s,f ) (f + (s*CD_FRAMES) + (m*CD_FRAMES*CD_SECS))

static uint32_t inline lbatomsf( uint32_t lba ) {

    union cdrom_addr addr;

    lba = lba + CD_MSF_OFFSET;

    addr.msf.frame = lba % CD_FRAMES;

    int seconds = lba / CD_FRAMES;

    addr.msf.second = seconds % CD_SECS;

    addr.msf.minute = seconds / CD_SECS;

    return addr.lba;

}

#define LBATOMSF( lba ) lbatomsf(lba)

static gboolean linux_image_is_valid( FILE *f );

static gdrom_disc_t linux_open_device( const gchar *filename, FILE *f );

static gdrom_error_t linux_read_disc_toc( gdrom_image_t disc );

static gdrom_error_t linux_read_sector( gdrom_disc_t disc, uint32_t sector,

					int mode, char *buf, uint32_t *length );

static gdrom_error_t linux_send_command( int fd, char *cmd, char *buffer, size_t *buflen,

					 int direction );

static int linux_drive_status( gdrom_disc_t disc );

struct gdrom_image_class linux_device_class = { "Linux", NULL,

					     linux_image_is_valid, linux_open_device };

static gboolean linux_image_is_valid( FILE *f )

{

    struct stat st;

    struct cdrom_tochdr tochdr;

    if( fstat(fileno(f), &st) == -1 ) {

	return FALSE; /* can't stat device? */

    }

    if( !S_ISBLK(st.st_mode) ) {

	return FALSE; /* Not a block device */

    }

    if( ioctl(fileno(f), CDROMREADTOCHDR, &tochdr) == -1 ) {

	/* Quick check that this is really a CD */

	return FALSE;

    }

    return TRUE;

}

static gdrom_disc_t linux_open_device( const gchar *filename, FILE *f ) 

{

    gdrom_disc_t disc;

    int fd = fileno(f);

    disc = gdrom_image_new(f);

    if( disc == NULL ) {

	ERROR("Unable to allocate memory!");

	return NULL;

    }

    gdrom_error_t status = linux_read_disc_toc( (gdrom_image_t)disc );

    if( status != 0 ) {

	disc->close(disc);

	if( status == 0xFFFF ) {

	    ERROR("Unable to load disc table of contents (%s)", strerror(errno));

	} else {

	    ERROR("Unable to load disc table of contents (sense %d,%d)",

		  status &0xFF, status >> 8 );

	}

	return NULL;

    }

    disc->read_sector = linux_read_sector;

    disc->drive_status = linux_drive_status;

    ((gdrom_image_t)disc)->disc_type = IDE_DISC_CDROM;

    return disc;

}

static int linux_drive_status( gdrom_disc_t disc )

{

    int fd = fileno(((gdrom_image_t)disc)->file);

    int status = ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);

    if( status == CDS_DISC_OK ) {

	status = ioctl(fd, CDROM_MEDIA_CHANGED, CDSL_CURRENT);

	if( status != 0 ) {

	    linux_read_disc_toc(disc);

	}

	return ((gdrom_image_t)disc)->disc_type | IDE_DISC_READY;

    } else {

	return IDE_DISC_NONE;

    }

}

/**

 * Read the full table of contents into the disc from the device.

 */

static gdrom_error_t linux_read_disc_toc( gdrom_image_t disc )

{

    int fd = fileno(disc->file);

    unsigned char buf[MAXTOCSIZE];

    int buflen = sizeof(buf);

    char cmd[12] = { 0x43, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

    cmd[7] = (sizeof(buf))>>8;

    cmd[8] = (sizeof(buf))&0xFF;

    memset( buf, 0, sizeof(buf) );

    gdrom_error_t status = linux_send_command( fd, cmd, buf, &buflen, CGC_DATA_READ );

    if( status != 0 ) {

	return status;

    }

    int max_track = 0;

    int last_track = -1;

    int leadout = -1;

    int len = (buf[0] << 8) | buf[1];

    int session_type = GDROM_MODE1;

    int i;

    for( i = 4; i<len; i+=11 ) {

	int session = buf[i];

	int adr = buf[i+1] >> 4;

	int point = buf[i+3];

	if( adr == 0x01 && point > 0 && point < 100 ) {

	    /* Track info */

	    int trackno = point-1;

	    if( point > max_track ) {

		max_track = point;

	    }

	    disc->track[trackno].flags = (buf[i+1] & 0x0F) << 4;

	    disc->track[trackno].session = session - 1;

	    disc->track[trackno].lba = MSFTOLBA(buf[i+8],buf[i+9],buf[i+10]);

	    if( disc->track[trackno].flags & TRACK_DATA ) {

		disc->track[trackno].mode = GDROM_MODE1;

	    } else {

		disc->track[trackno].mode = GDROM_CDDA;

	    }

	    if( last_track != -1 ) {

		disc->track[last_track].sector_count = disc->track[trackno].lba -

		    disc->track[last_track].lba;

	    }

	    last_track = trackno;

	} else switch( (adr << 8) | point ) {

	case 0x1A0: /* session info */

	    if( buf[i+9] == 0x20 ) {

		session_type = GDROM_MODE2;

	    } else {

		session_type = GDROM_MODE1;

	    }

	case 0x1A2: /* leadout */

	    leadout = MSFTOLBA(buf[i+8], buf[i+9], buf[i+10]);

	    break;

	}

    }

    disc->track_count = max_track;

    if( leadout != -1 && last_track != -1 ) {

	disc->track[last_track].sector_count = leadout - disc->track[last_track].lba;

    }

    return 0;

}

static gdrom_error_t linux_read_sector( gdrom_disc_t disc, uint32_t sector,

					int mode, char *buf, uint32_t *length )

{

    gdrom_image_t image = (gdrom_image_t)disc;

    int fd = fileno(image->file);

    uint32_t real_sector = sector - CD_MSF_OFFSET;

    uint32_t sector_size = MAX_SECTOR_SIZE;

    int i;

    char cmd[12] = { 0xBE, 0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

    cmd[1] = (mode & 0x0E) << 1;

    cmd[2] = (real_sector >> 24) & 0xFF;

    cmd[3] = (real_sector >> 16) & 0xFF;

    cmd[4] = (real_sector >> 8) & 0xFF;

    cmd[5] = real_sector & 0xFF;

    cmd[6] = 0;

    cmd[7] = 0;

    cmd[8] = 1;

    cmd[9] = 0x10;

    gdrom_error_t status = linux_send_command( fd, cmd, buf, &sector_size, CGC_DATA_READ );

    if( status != 0 ) {

	return status;

    }

    *length = 2048;

    return 0;

}

/**

 * Send a packet command to the device and wait for a response. 

 * @return 0 on success, -1 on an operating system error, or a sense error

 * code on a device error.

 */

static gdrom_error_t linux_send_command( int fd, char *cmd, char *buffer, size_t *buflen,

					 int direction )

{

    struct request_sense sense;

    struct cdrom_generic_command cgc;

    memset( &cgc, 0, sizeof(cgc) );

    memset( &sense, 0, sizeof(sense) );

    memcpy( cgc.cmd, cmd, 12 );

    cgc.buffer = buffer;

    cgc.buflen = *buflen;

    cgc.sense = &sense;

    cgc.data_direction = direction;

    if( ioctl(fd, CDROM_SEND_PACKET, &cgc) == -1 ) {

	if( sense.sense_key == 0 ) {

	    return -1; 

	} else {

	    /* TODO: Map newer codes back to the ones used by the gd-rom. */

	    return sense.sense_key | (sense.asc<<8);

	}

    } else {

	*buflen = cgc.buflen;

	return 0;

    }

}