/**

  * $Id: linux.c,v 1.5 2007-10-06 08:58:00 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, unsigned char *buf, uint32_t *length );

 static gdrom_error_t linux_send_command( int fd, char *cmd, unsigned 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;

     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( (gdrom_image_t)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];

     size_t 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, unsigned 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;

     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, unsigned 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;

     }

 }