sjcd.c

讲述linux的初始化过程

	}
	if( sjcd_mode != SCMD_MODE_COOKED ){
#if defined( SJCD_TRACE )
	  printk( "SJCD_S_READ: mode failed: goto to SJCD_S_STOP mode\n" );
#endif
	  sjcd_transfer_state = SJCD_S_STOP;
	  goto ReSwitch;
	}
      }

      if( CURRENT_IS_VALID ){
	struct sjcd_play_msf msf;

	sjcd_next_bn = CURRENT->sector / 4;
	hsg2msf( sjcd_next_bn, &msf.start );
	msf.end.min = 0; msf.end.sec = 0;            
	msf.end.frame = sjcd_read_count = SJCD_BUF_SIZ;
#if defined( SJCD_TRACE )
	printk( "SJCD: ---reading msf-address %x:%x:%x  %x:%x:%x\n",
	       msf.start.min, msf.start.sec, msf.start.frame,
	       msf.end.min,   msf.end.sec,   msf.end.frame );
	printk( "sjcd_next_bn:%x buf_in:%x buf_out:%x buf_bn:%x\n", \
	     sjcd_next_bn, sjcd_buf_in, sjcd_buf_out,
	     sjcd_buf_bn[ sjcd_buf_in ] );
#endif	
	sjcd_send_6_cmd( SCMD_DATA_READ, &msf );
	sjcd_transfer_state = SJCD_S_DATA;
	sjcd_transfer_timeout = 500;
#if defined( SJCD_TRACE )
	printk( "SJCD_S_READ: go to SJCD_S_DATA mode\n" );
#endif
      } else {
#if defined( SJCD_TRACE )
	printk( "SJCD_S_READ: nothing to read: go to SJCD_S_STOP mode\n" );
#endif
	sjcd_transfer_state = SJCD_S_STOP;
	goto ReSwitch;
      }
    }
#if defined( SJCD_GATHER_STAT )
    else statistic.read_ticks++;
#endif
    break;
  }

  case SJCD_S_DATA:{
    unsigned char stat;

  sjcd_s_data: stat = inb( SJCDPORT( 1 ) );
#if defined( SJCD_TRACE )
    printk( "SJCD_S_DATA: status = 0x%02x\n", stat );
#endif
    if( SJCD_STATUS_AVAILABLE( stat ) ){
      /*
       * No data is waiting for us in the drive buffer. Status of operation
       * completion is available. Read and parse it.
       */
      sjcd_load_status();

      if( !sjcd_status_valid || sjcd_command_failed ){
#if defined( SJCD_TRACE )
	printk( "SJCD: read block %d failed, maybe audio disk? Giving up\n",
	       sjcd_next_bn );
#endif
	if( CURRENT_IS_VALID ) end_request( 0 );
#if defined( SJCD_TRACE )
	printk( "SJCD_S_DATA: pre-cmd failed: go to SJCD_S_STOP mode\n" );
#endif
	sjcd_transfer_state = SJCD_S_STOP;
	goto ReSwitch;
      }

      if( !sjcd_media_is_available ){
	printk( "SJCD_S_DATA: no disk: go to SJCD_S_STOP mode\n" );
	sjcd_transfer_state = SJCD_S_STOP;
	goto ReSwitch;
      }

      sjcd_transfer_state = SJCD_S_READ;
      goto ReSwitch;
    } else if( SJCD_DATA_AVAILABLE( stat ) ){
      /*
       * One frame is read into device buffer. We must copy it to our memory.
       * Otherwise cdrom hangs up. Check to see if we have something to copy
       * to.
       */
      if( !CURRENT_IS_VALID && sjcd_buf_in == sjcd_buf_out ){
#if defined( SJCD_TRACE )
	printk( "SJCD_S_DATA: nothing to read: go to SJCD_S_STOP mode\n" );
	printk( " ... all the date would be discarded\n" );
#endif
	sjcd_transfer_state = SJCD_S_STOP;
	goto ReSwitch;
      }

      /*
       * Everything seems to be OK. Just read the frame and recalculate
       * indices.
       */
      sjcd_buf_bn[ sjcd_buf_in ] = -1; /* ??? */
      insb( SJCDPORT( 2 ), sjcd_buf + 2048 * sjcd_buf_in, 2048 );
#if defined( SJCD_TRACE )
      printk( "SJCD_S_DATA: next_bn=%d, buf_in=%d, buf_out=%d, buf_bn=%d\n",
	     sjcd_next_bn, sjcd_buf_in, sjcd_buf_out,
	     sjcd_buf_bn[ sjcd_buf_in ] );
#endif
      sjcd_buf_bn[ sjcd_buf_in ] = sjcd_next_bn++;
      if( sjcd_buf_out == -1 ) sjcd_buf_out = sjcd_buf_in;
      if( ++sjcd_buf_in == SJCD_BUF_SIZ ) sjcd_buf_in = 0;

      /*
       * Only one frame is ready at time. So we should turn over to wait for
       * another frame. If we need that, of course.
       */
      if( --sjcd_read_count == 0 ){
	/*
	 * OK, request seems to be precessed. Continue transferring...
	 */
	if( !sjcd_transfer_is_active ){
	  while( CURRENT_IS_VALID ){
	    /*
	     * Continue transferring.
	     */
	    sjcd_transfer();
	    if( CURRENT->nr_sectors == 0 ) end_request( 1 );
	    else break;
	  }
	}
	if( CURRENT_IS_VALID &&
	   ( CURRENT->sector / 4 < sjcd_next_bn ||
	    CURRENT->sector / 4 > sjcd_next_bn + SJCD_BUF_SIZ ) ){
#if defined( SJCD_TRACE )
	  printk( "SJCD_S_DATA: can't read: go to SJCD_S_STOP mode\n" );
#endif
	  sjcd_transfer_state = SJCD_S_STOP;
	  goto ReSwitch;
	}
      }
      /*
       * Now we should turn around rather than wait for while.
       */
      goto sjcd_s_data;
    }
#if defined( SJCD_GATHER_STAT )
    else statistic.data_ticks++;
#endif
    break;
  }

  case SJCD_S_STOP:{
    sjcd_read_count = 0;
    sjcd_send_cmd( SCMD_STOP );
    sjcd_transfer_state = SJCD_S_STOPPING;
    sjcd_transfer_timeout = 500;
#if defined( SJCD_GATHER_STAT )
    statistic.stop_ticks++;
#endif
    break;
  }

  case SJCD_S_STOPPING:{
    unsigned char stat;
    
    stat = inb( SJCDPORT( 1 ) );
#if defined( SJCD_TRACE )
    printk( "SJCD_S_STOP: status = 0x%02x\n", stat );
#endif      
    if( SJCD_DATA_AVAILABLE( stat ) ){
      int i;
#if defined( SJCD_TRACE )
      printk( "SJCD_S_STOP: discard data\n" );
#endif
      /*
       * Discard all the data from the pipe. Foolish method.
       */
      for( i = 2048; i--; ( void )inb( SJCDPORT( 2 ) ) );
      sjcd_transfer_timeout = 500;
    } else if( SJCD_STATUS_AVAILABLE( stat ) ){
      sjcd_load_status();
      if( sjcd_status_valid && sjcd_media_is_changed ) {
	sjcd_toc_uptodate = 0;
	sjcd_invalidate_buffers();
      }
      if( CURRENT_IS_VALID ){
	if( sjcd_status_valid ) sjcd_transfer_state = SJCD_S_READ;
	else sjcd_transfer_state = SJCD_S_START;
      } else sjcd_transfer_state = SJCD_S_IDLE;
      goto ReSwitch;
    }
#if defined( SJCD_GATHER_STAT )
    else statistic.stopping_ticks++;
#endif
    break;
  }

  default:
    printk( "SJCD: poll: invalid state %d\n", sjcd_transfer_state );
    return;
  }
  
  if( --sjcd_transfer_timeout == 0 ){
    printk( "SJCD: timeout in state %d\n", sjcd_transfer_state );
    while( CURRENT_IS_VALID ) end_request( 0 );
    sjcd_send_cmd( SCMD_STOP );
    sjcd_transfer_state = SJCD_S_IDLE;
    goto ReSwitch;
    }

  /*
   * Get back in some time. 1 should be replaced with count variable to
   * avoid unnecessary testings.
   */
  SJCD_SET_TIMER( sjcd_poll, 1 );
}

static void do_sjcd_request( request_queue_t * q ){
#if defined( SJCD_TRACE )
  printk( "SJCD: do_sjcd_request(%ld+%ld)\n",
	 CURRENT->sector, CURRENT->nr_sectors );
#endif
  sjcd_transfer_is_active = 1;
  while( CURRENT_IS_VALID ){
    /*
     * Who of us are paranoiac?
     */
    if( CURRENT->bh && !buffer_locked(CURRENT->bh) )
      panic( DEVICE_NAME ": block not locked" );

    sjcd_transfer();
    if( CURRENT->nr_sectors == 0 ) end_request( 1 );
    else {
      sjcd_buf_out = -1;         /* Want to read a block not in buffer */
      if( sjcd_transfer_state == SJCD_S_IDLE ){
	if( !sjcd_toc_uptodate ){
	  if( sjcd_update_toc() < 0 ){
	    printk( "SJCD: transfer: discard\n" );
	    while( CURRENT_IS_VALID ) end_request( 0 );
	    break;
	  }
	}
	sjcd_transfer_state = SJCD_S_START;
	SJCD_SET_TIMER( sjcd_poll, HZ/100 );
      }
      break;
    }
  }
  sjcd_transfer_is_active = 0;
#if defined( SJCD_TRACE )
  printk( "sjcd_next_bn:%x sjcd_buf_in:%x sjcd_buf_out:%x sjcd_buf_bn:%x\n",
	 sjcd_next_bn, sjcd_buf_in, sjcd_buf_out, sjcd_buf_bn[ sjcd_buf_in ] );
  printk( "do_sjcd_request ends\n" );
#endif
}

/*
 * Open the device special file. Check disk is in.
 */
int sjcd_open( struct inode *ip, struct file *fp ){
  /*
   * Check the presence of device.
   */
  if( !sjcd_present ) return( -ENXIO );
  
  /*
   * Only read operations are allowed. Really? (:-)
   */
  if( fp->f_mode & 2 ) return( -EROFS );
  
  MOD_INC_USE_COUNT;

  if( sjcd_open_count == 0 ){
    int s, sjcd_open_tries;
/* We don't know that, do we? */
/*
    sjcd_audio_status = CDROM_AUDIO_NO_STATUS;
*/
    sjcd_mode = 0;
    sjcd_door_was_open = 0;
    sjcd_transfer_state = SJCD_S_IDLE;
    sjcd_invalidate_buffers();
    sjcd_status_valid = 0;

    /*
     * Strict status checking.
     */
    for( sjcd_open_tries = 4; --sjcd_open_tries; ){
      if( !sjcd_status_valid ) sjcd_get_status();
      if( !sjcd_status_valid ){
#if defined( SJCD_DIAGNOSTIC )
	printk( "SJCD: open: timed out when check status.\n" );
#endif
	goto err_out;
      } else if( !sjcd_media_is_available ){
#if defined( SJCD_DIAGNOSTIC )
	printk("SJCD: open: no disk in drive\n");
#endif
	if( !sjcd_door_closed ){
	  sjcd_door_was_open = 1;
#if defined( SJCD_TRACE )
	  printk("SJCD: open: close the tray\n");
#endif
	  s = sjcd_tray_close();
	  if( s < 0 || !sjcd_status_valid || sjcd_command_failed ){
#if defined( SJCD_DIAGNOSTIC )
	    printk("SJCD: open: tray close attempt failed\n");
#endif
	    goto err_out;
	  }
	  continue;
	} else goto err_out;
      }
      break;
    }
    s = sjcd_tray_lock();
    if( s < 0 || !sjcd_status_valid || sjcd_command_failed ){
#if defined( SJCD_DIAGNOSTIC )
      printk("SJCD: open: tray lock attempt failed\n");
#endif
      goto err_out;
    }
#if defined( SJCD_TRACE )
    printk( "SJCD: open: done\n" );
#endif
  }

  ++sjcd_open_count;
  return( 0 );

err_out:
  MOD_DEC_USE_COUNT;
  return( -EIO );
}

/*
 * On close, we flush all sjcd blocks from the buffer cache.
 */
static int sjcd_release( struct inode *inode, struct file *file ){
  int s;

#if defined( SJCD_TRACE )
  printk( "SJCD: release\n" );
#endif
#ifdef MODULE
  MOD_DEC_USE_COUNT;
#endif
  if( --sjcd_open_count == 0 ){
    sjcd_invalidate_buffers();
    s = sjcd_tray_unlock();
    if( s < 0 || !sjcd_status_valid || sjcd_command_failed ){
#if defined( SJCD_DIAGNOSTIC )
      printk("SJCD: release: tray unlock attempt failed.\n");
#endif
    }
    if( sjcd_door_was_open ){
      s = sjcd_tray_open();
      if( s < 0 || !sjcd_status_valid || sjcd_command_failed ){
#if defined( SJCD_DIAGNOSTIC )
	printk("SJCD: release: tray unload attempt failed.\n");
#endif
      }
    }
  }
  return 0;
}

/*
 * A list of file operations allowed for this cdrom.
 */
static struct block_device_operations sjcd_fops = {
	open:			sjcd_open,
	release:		sjcd_release,
	ioctl:			sjcd_ioctl,
	check_media_change:	sjcd_disk_change,
};

static int blksize = 2048;
static int secsize = 2048;

/*
 * Following stuff is intended for initialization of the cdrom. It
 * first looks for presence of device. If the device is present, it
 * will be reset. Then read the version of the drive and load status.
 * The version is two BCD-coded bytes.
 */
static struct {
  unsigned char major, minor;
} sjcd_version;

/*
 * Test for presence of drive and initialize it. Called at boot time.
 * Probe cdrom, find out version and status.
 */
int __init sjcd_init( void ){
  int i;

  printk(KERN_INFO "SJCD: Sanyo CDR-H94A cdrom driver version %d.%d.\n", SJCD_VERSION_MAJOR,
    SJCD_VERSION_MINOR);

#if defined( SJCD_TRACE )
  printk("SJCD: sjcd=0x%x: ", sjcd_base);
#endif  

	hardsect_size[MAJOR_NR] = &secsize;
	blksize_size[MAJOR_NR] = &blksize;

  if( devfs_register_blkdev( MAJOR_NR, "sjcd", &sjcd_fops ) != 0 ){
    printk( "SJCD: Unable to get major %d for Sanyo CD-ROM\n", MAJOR_NR );
    return( -EIO );
  }
  
  blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), DEVICE_REQUEST);
  read_ahead[ MAJOR_NR ] = 4;
  register_disk(NULL, MKDEV(MAJOR_NR,0), 1, &sjcd_fops, 0);
  
  if( check_region( sjcd_base, 4 ) ){
    printk( "SJCD: Init failed, I/O port (%X) is already in use\n",
      sjcd_base );
    sjcd_cleanup();
    return( -EIO );
  }
  
  /*
   * Check for card. Since we are booting now, we can't use standard
   * wait algorithm.
   */
  printk(KERN_INFO "SJCD: Resetting: " );
  sjcd_send_cmd( SCMD_RESET );
  for( i = 1000; i > 0 && !sjcd_status_valid; --i ){
    unsigned long timer;

    /*
     * Wait 10ms approx.
     */
    for( timer = jiffies; time_before_eq(jiffies, timer); );
    if ( (i % 100) == 0 ) printk( "." );
    ( void )sjcd_check_status();
  }
  if( i == 0 || sjcd_command_failed ){
    printk( " reset failed, no drive found.\n" );
    sjcd_cleanup();
    return( -EIO );
  } else printk( "\n" );

  /*
   * Get and print out cdrom version.
   */
  printk(KERN_INFO "SJCD: Getting version: " );
  sjcd_send_cmd( SCMD_GET_VERSION );
  for( i = 1000; i > 0 && !sjcd_status_valid; --i ){
    unsigned long timer;

    /*
     * Wait 10ms approx.
     */
    for( timer = jiffies; time_before_eq(jiffies, timer); );
    if ( (i % 100) == 0 ) printk( "." );
    ( void )sjcd_check_status();
  }
  if( i == 0 || sjcd_command_failed ){
    printk( " get version failed, no drive found.\n" );
    sjcd_cleanup();
    return( -EIO );
  }

  if( sjcd_load_response( &sjcd_version, sizeof( sjcd_version ) ) == 0 ){
    printk( " %1x.%02x\n", ( int )sjcd_version.major,
	     ( int )sjcd_version.minor );
  } else {
    printk( " read version failed, no drive found.\n" );
    sjcd_cleanup();
    return( -EIO );
  }

  /*
   * Check and print out the tray state. (if it is needed?).
   */
  if( !sjcd_status_valid ){
    printk(KERN_INFO "SJCD: Getting status: " );
    sjcd_send_cmd( SCMD_GET_STATUS );
    for( i = 1000; i > 0 && !sjcd_status_valid; --i ){
      unsigned long timer;

      /*
       * Wait 10ms approx.
       */
      for( timer = jiffies; time_before_eq(jiffies, timer); );
      if ( (i % 100) == 0 ) printk( "." );
      ( void )sjcd_check_status();
    }
    if( i == 0 || sjcd_command_failed ){
      printk( " get status failed, no drive found.\n" );
      sjcd_cleanup();
      return( -EIO );
    } else printk( "\n" );
  }

  printk(KERN_INFO "SJCD: Status: port=0x%x.\n", sjcd_base);
  devfs_register (NULL, "sjcd", DEVFS_FL_DEFAULT, MAJOR_NR, 0,
		  S_IFBLK | S_IRUGO | S_IWUGO, &sjcd_fops, NULL);

  sjcd_present++;
  return( 0 );
}

static int
sjcd_cleanup(void)
{
  if( (devfs_unregister_blkdev(MAJOR_NR, "sjcd") == -EINVAL) )
    printk( "SJCD: cannot unregister device.\n" );
  else {
    release_region( sjcd_base, 4 );
    blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));
  }

  return(0);
}


void __exit sjcd_exit(void)
{
  devfs_unregister(devfs_find_handle(NULL, "sjcd", 0, 0, DEVFS_SPECIAL_BLK,0));
  if ( sjcd_cleanup() )
    printk( "SJCD: module: cannot be removed.\n" );
  else
    printk(KERN_INFO "SJCD: module: removed.\n");
}

#ifdef MODULE
module_init(sjcd_init);
#endif
module_exit(sjcd_exit);