diff -ru --new-file linux-1.0/config.in linux/config.in
--- linux-1.0/config.in	Sun Mar 13 00:17:37 1994
+++ linux/config.in	Tue Mar 15 11:42:38 1994
@@ -88,6 +88,7 @@
 bool 'Sony CDU31A CDROM driver support' CONFIG_CDU31A n
 bool 'Mitsumi CDROM driver support' CONFIG_MCD n
 bool 'Matsushita/Panasonic CDROM driver support' CONFIG_SBPCD n
+bool 'Sony CDU535 CDROM driver support' CONFIG_CDU535 y
 *
 * Filesystems
 *
diff -ru --new-file linux-1.0/drivers/block/Makefile linux/drivers/block/Makefile
--- linux-1.0/drivers/block/Makefile	Sun Mar  6 14:08:21 1994
+++ linux/drivers/block/Makefile	Tue Mar 15 11:37:54 1994
@@ -49,6 +49,11 @@
 SRCS := $(SRCS) xd.c
 endif
 
+ifdef CONFIG_CDU535
+OBJS := $(OBJS) sonycd535.o
+SRCS := $(SRCS) sonycd535.c
+endif
+
 all: block.a
 
 block.a: $(OBJS)
diff -ru --new-file linux-1.0/drivers/block/blk.h linux/drivers/block/blk.h
--- linux-1.0/drivers/block/blk.h	Sat Jan 29 12:55:06 1994
+++ linux/drivers/block/blk.h	Tue Mar 15 11:37:54 1994
@@ -82,6 +82,7 @@
 extern unsigned long hd_init(unsigned long mem_start, unsigned long mem_end);
 extern unsigned long cdu31a_init(unsigned long mem_start, unsigned long mem_end);
 extern unsigned long mcd_init(unsigned long mem_start, unsigned long mem_end);
+extern unsigned long init_sony535(unsigned long mem_start, unsigned long mem_end);
 extern int is_read_only(int dev);
 extern void set_device_ro(int dev,int flag);
 
@@ -160,6 +161,15 @@
 #define DEVICE_NAME "CD-ROM"
 #define DEVICE_INTR do_sr
 #define DEVICE_REQUEST do_sr_request
+#define DEVICE_NR(device) (MINOR(device))
+#define DEVICE_ON(device)
+#define DEVICE_OFF(device)
+
+#elif (MAJOR_NR == CDU535_CDROM_MAJOR)
+/* Sony CD-ROM */
+#define DEVICE_NAME "SONY-CD535"
+#define DEVICE_INTR do_scd535
+#define DEVICE_REQUEST do_scd535_request
 #define DEVICE_NR(device) (MINOR(device))
 #define DEVICE_ON(device)
 #define DEVICE_OFF(device)
diff -ru --new-file linux-1.0/drivers/block/ll_rw_blk.c linux/drivers/block/ll_rw_blk.c
--- linux-1.0/drivers/block/ll_rw_blk.c	Tue Feb  1 07:03:51 1994
+++ linux/drivers/block/ll_rw_blk.c	Tue Mar 15 11:37:54 1994
@@ -348,6 +348,9 @@
 	int correct_size;
 	struct blk_dev_struct * dev;
 	int i;
+#if defined(CONFIG_CDU535) && defined(CONFIG_CDU31A)
+	int sonycd_save_mem_start;
+#endif
 
 	/* Make sure that the first block contains something reasonable */
 	while (!*bh) {
@@ -488,9 +491,24 @@
 #ifdef CONFIG_BLK_DEV_XD
 	mem_start = xd_init(mem_start,mem_end);
 #endif
+#if defined(CONFIG_CDU535) && defined(CONFIG_CDU31A)
+	{  /* since controllers for 535 and 31A can be at same location
+	    * we have to be careful.
+	    */
+		sonycd_save_mem_start = mem_start;
+		mem_start = cdu31a_init(mem_start,mem_end);
+		if ( mem_start == sonycd_save_mem_start ) {  /* CDU31A not found */
+			mem_start = init_sony535(mem_start,mem_end);
+		}
+	}
+#else
 #ifdef CONFIG_CDU31A
 	mem_start = cdu31a_init(mem_start,mem_end);
 #endif
+#ifdef CONFIG_CDU535
+	mem_start = init_sony535(mem_start,mem_end);
+#endif
+#endif  /* CONFIG_CDU31A && CONFIG_CDU535 */
 #ifdef CONFIG_MCD
 	mem_start = mcd_init(mem_start,mem_end);
 #endif
diff -ru --new-file linux-1.0/drivers/block/sonycd535.c linux/drivers/block/sonycd535.c
--- linux-1.0/drivers/block/sonycd535.c	Thu Jan  1 00:00:00 1970
+++ linux/drivers/block/sonycd535.c	Tue Mar 15 11:37:55 1994
@@ -0,0 +1,1537 @@
+/*
+ * Sony CDU-535 interface device driver
+ *
+ * This is a modified version of the CDU-31A device driver (see below).
+ * Changes were made using documentation for the CDU-531 (which Sony
+ * assures me is very similar to the 535) and partial disassembly of the
+ * DOS driver.  I used Minyard's driver and replaced the the CDU-31A 
+ * commands with the CDU-531 commands.  This was complicated by a different
+ * interface protocol with the drive.  The driver is still polled.
+ *
+ * Data transfer rate is about 110 Kb/sec, theoretical maximum is 150 Kb/sec.
+ * I tried polling without the sony_sleep during the data transfers but
+ * it did not speed things up any.
+ *
+ *  5/23/93 (rgj) changed the major number to 21 to get rid of conflict
+ * with CDU-31A driver.  This is the also the number from the Linux
+ * Device Driver Registry for the Sony Drive.  Hope nobody else is using it.
+ *
+ *  8/29/93 (rgj) remove the configuring of the interface board address
+ * from the top level configuration, you have to modify it in this file.
+ *
+ * Things to do:
+ *	- handle errors and status better, put everything into a single word
+ *	- use interrupts, DMA
+ *
+ *  Known Bugs:
+ *	-
+ *
+ *   Ron Jeppesen (ronj.an@site007.saic.com)
+ *
+ *
+ *------------------------------------------------------------------------
+ * Sony CDROM interface device driver.
+ *
+ * Corey Minyard (minyard@wf-rch.cirr.com) (CDU-535 complaints to ronj above)
+ *
+ * Colossians 3:17
+ *
+ * The Sony interface device driver handles Sony interface CDROM
+ * drives and provides a complete block-level interface as well as an
+ * ioctl() interface compatible with the Sun (as specified in
+ * include/linux/cdrom.h).  With this interface, CDROMs can be
+ * accessed and standard audio CDs can be played back normally.
+ *
+ * This interface is (unfortunatly) a polled interface.  This is
+ * because most Sony interfaces are set up with DMA and interrupts
+ * disables.  Some (like mine) do not even have the capability to
+ * handle interrupts or DMA.  For this reason you will see a lot of
+ * the following:
+ *
+ *   retry_count = jiffies+ SONY_JIFFIES_TIMEOUT;
+ *   while ((retry_count > jiffies) && (! <some condition to wait for))
+ *   {
+ *      while (handle_sony_cd_attention())
+ *         ;
+ *
+ *      sony_sleep();
+ *   }
+ *   if (the condition not met)
+ *   {
+ *      return an error;
+ *   }
+ *
+ * This ugly hack waits for something to happen, sleeping a little
+ * between every try.  it also handles attentions, which are
+ * asyncronous events from the drive informing the driver that a disk
+ * has been inserted, removed, etc.
+ *
+ * One thing about these drives: They talk in MSF (Minute Second Frame) format.
+ * There are 75 frames a second, 60 seconds a minute, and up to 75 minutes on a
+ * disk.  The funny thing is that these are sent to the drive in BCD, but the
+ * interface wants to see them in decimal.  A lot of conversion goes on.
+ *
+ *  Copyright (C) 1993  Corey Minyard
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+
+#include <linux/config.h>
+#ifdef CONFIG_CDU535
+
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/hdreg.h>
+#include <linux/genhd.h>
+
+#define REALLY_SLOW_IO
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/segment.h>
+
+#include <linux/cdrom.h>
+#include <linux/sonycd535.h>
+
+#define MAJOR_NR CDU535_CDROM_MAJOR
+#include "blk.h"
+
+/*
+ * this is the base address of the interface card for the Sony CDU535
+ * CDROM drive.  If your jumpers are set for an address other than
+ * this one (the default), change the following line to the
+ * proper address.
+ */
+#define CDU535_ADDRESS	(0x340)
+
+#define DEBUG
+
+/*
+ *  SONY535_BUFFER_SIZE determines the size of internal buffer used
+ *  by the drive.  It must be at least 2K and the larger the buffer
+ *  the better the transfer rate.  It does however take system memory.
+ *   On my system I get the following transfer rates using dd to read
+ *  10 Mb off /dev/cdrom.
+ *
+ *      8K buffer		 43 Kb/sec
+ *	16K buffer		 66 Kb/sec
+ *	32K buffer		 91 Kb/sec
+ *	64K buffer		111 Kb/sec
+ *	128K buffer		123 Kb/sec
+ *	512K buffer		123 Kb/sec
+ */
+#define SONY535_BUFFER_SIZE	(64*1024)
+
+/*
+ *  if LOCK_DOORS is defined then the eject button is disabled while
+ * the device is open.
+ */
+#define LOCK_DOORS
+
+static int read_subcode(void);
+static void sony_get_toc(void);
+static int scd_open( struct inode *inode, struct file *filp );
+static inline unsigned int int_to_bcd(unsigned int val);
+static unsigned int bcd_to_int(unsigned int bcd);
+static int do_sony_cmd( Byte *cmd, int nCmd, Byte status[2], 
+                 Byte *response, int nResponse, int ignoreStatusBit7 );
+
+/* The base I/O address of the Sony Interface.  This is a variable (not a
+   #define) so it can be easily changed via some future ioctl() */
+static unsigned short sony_cd_base_io = CDU535_ADDRESS;
+
+/*
+ * The following are I/O addresses of the various registers for the drive.  The
+ * comment for the base address also applies here.
+ */
+static unsigned short select_unit_reg;
+static unsigned short result_reg;
+static unsigned short command_reg;
+static unsigned short read_status_reg;
+static unsigned short data_reg;
+
+static int initialized = 0;                /* Has the drive been initialized? */
+static int sony_disc_changed = 1;          /* Has the disk been changed
+                                              since the last check? */
+static int sony_toc_read = 0;              /* Has the table of contents been
+                                              read? */
+static unsigned int sony_buffer_size;      /* Size in bytes of the read-ahead
+                                              buffer. */
+static unsigned int sony_buffer_sectors;   /* Size (in 2048 byte records) of
+                                              the read-ahead buffer. */
+static unsigned int sony_usage = 0;        /* How many processes have the
+                                              drive open. */
+
+static int sony_first_block = -1;          /* First OS block (512 byte) in
+                                              the read-ahead buffer */
+static int sony_last_block = -1;           /* Last OS block (512 byte) in
+                                              the read-ahead buffer */
+
+static struct s535_sony_toc *sony_toc;           /* Points to the table of
+                                                    contents. */
+static struct s535_sony_subcode *last_sony_subcode; /* Points to the last
+                                                    subcode address read */
+static unsigned char *sony_buffer;               /* Points to the read-ahead
+                                                    buffer */
+static int sony_inuse = 0;		/* is the drive in use? Only one
+					   open at a time allowed */
+
+/*
+ * The audio status uses the values from read subchannel data as specified
+ * in include/linux/cdrom.h.
+ */
+static int sony_audio_status = CDROM_AUDIO_NO_STATUS;
+
+/*
+ * The following are a hack for pausing and resuming audio play.  The drive
+ * does not work as I would expect it, if you stop it then start it again,
+ * the drive seeks back to the beginning and starts over.  This holds the
+ * position during a pause so a resume can restart it.  It uses the
+ * audio status variable above to tell if it is paused.
+ *   I just kept the CDU-31A driver behavior rather than using the PAUSE
+ * command on the CDU-535.
+ */
+static unsigned char cur_pos_msf[3] = { 0, 0, 0 };
+static unsigned char final_pos_msf[3] = { 0, 0, 0 };
+
+
+/*
+ * This routine returns 1 if the disk has been changed since the last
+ * check or 0 if it hasn't.  Setting flag to 0 resets the changed flag.
+ */
+int
+sony535_check_cdrom_media_change(int full_dev, int flag)
+{
+   int retval, target;
+
+   target = MINOR(full_dev);
+
+   if (target > 0) {
+      printk("Sony CD-ROM request error: invalid device.\n");
+      return 0;
+   }
+
+    /* if driver is not initialized, always return 0 */
+   retval = ( initialized ? sony_disc_changed : 0 );
+   if (!flag)
+   {
+      sony_disc_changed = 0;
+   }
+
+   return retval;
+}
+
+
+/*
+ * Wait a little while (used for polling the drive).  If in initialization,
+ * setting a timeout doesn't work, so just loop for a while  (we trust
+ * that the sony_sleep() call is protected by a test for proper jiffies count).
+ */
+static inline void
+sony_sleep(void)
+{
+   current->state = TASK_INTERRUPTIBLE;
+   current->timeout = jiffies;
+   schedule();
+}
+
+/*------------------start of SONY CDU535 very specific ---------------------*/
+
+/****************************************************************************
+ * void select_unit( int unit_no )
+ *
+ *  Select the specified unit (0-3) so that subsequent commands reference it
+ ****************************************************************************/
+static void 
+select_unit( int unit_no )
+{
+   unsigned int select_mask = ~(1 << unit_no);
+   outb( select_mask, select_unit_reg );
+}  /* select_unit() */
+
+/***************************************************************************
+ * int read_result_reg( unsigned char *data_ptr )
+ *
+ *  Read a result byte from the Sony CDU controller, store in location pointed
+ * to by data_ptr.  Return zero on success, TIME_OUT if we did not receive
+ * data.
+ ***************************************************************************/
+static int 
+read_result_reg( unsigned char *data_ptr )
+{
+   int retry_count;
+   int read_status;
+  
+   retry_count = jiffies + SONY_JIFFIES_TIMEOUT;
+   while ( retry_count > jiffies ) 
+   {
+      if ( ((read_status=inb(read_status_reg)) & SONY535_RESULT_NOT_READY_BIT) == 0 ) 
+      {
+#if 0
+         printk("read_result_reg(): readStatReg = 0x%x\n", read_status );
+#endif
+         *data_ptr = inb(result_reg);
+         return( 0 );
+      }
+      else 
+      {
+         sony_sleep();
+      }
+   }
+   printk(" Sony CDROM read_result_reg: TIME OUT!\n");
+   return( TIME_OUT );
+}  /* read_result_reg() */
+
+/****************************************************************************
+ * int read_exec_status( Byte status[2] )
+ *
+ *  Read the execution status of the last command and put into status. 
+ * Handles reading second status word if available.  Returns 0 on success,
+ * TIME_OUT on failure.
+ ****************************************************************************/
+static int 
+read_exec_status( Byte status[2] )
+{
+   status[1] = 0;
+   if ( read_result_reg( &(status[0]) ) != 0 ) return( TIME_OUT );
+   if ( (status[0] & 0x80) != 0 )  /* byte two follows */
+   {
+      if ( read_result_reg( &(status[1]) ) != 0 ) return( TIME_OUT );
+   }
+#if 0
+   printk("read_exec_status: read 0x%x\n", status[0] );
+   if (status[0] & 0x80) printk(" and 0x%x\n", status[1] );
+   printk("\n");
+#endif
+   return( 0 );
+}  /* read_exec_status() */
+
+/****************************************************************************
+ * int check_drive_status( void )
+ *
+ *  Check the current drive status.  Using this before executing a command
+ * takes care of the problem of unsolicited drive status-2 messages.
+ * Add a check of the audio status if we think the disk is playing.
+ ****************************************************************************/
+static int 
+check_drive_status( void )
+{
+   Byte status, e_status[2];
+   int CDD, ATN;
+   unsigned char cmd;
+  
+   select_unit(0);
+   if ( sony_audio_status == CDROM_AUDIO_PLAY )  /* check status */
+   {
+      outb( SONY535_REQUEST_AUDIO_STATUS, command_reg );
+      if ( read_result_reg( &status ) == 0 ) 
+      {
+         switch( status ) 
+         {
+            case 0x0:  break;			/* play in progress */
+            case 0x1:  break;			/* paused */
+            case 0x3:				/* audio play completed */
+            case 0x5:				/* play not requested */
+                       sony_audio_status = CDROM_AUDIO_COMPLETED;
+                       read_subcode();
+                       break;
+            case 0x4:				/* error during play */
+                       sony_audio_status = CDROM_AUDIO_ERROR;
+                       break;
+         }
+      }
+   }
+    /* now check drive status */
+   outb( SONY535_REQUEST_DRIVE_STATUS_2, command_reg );
+   if ( read_result_reg( &status ) != 0 ) 
+      return( TIME_OUT );
+
+#if 0
+   printk("--check_drive_status() got 0x%x\n", status );
+#endif
+  
+   if ( status == 0 ) return( 0 );
+  
+   ATN = status & 0xf;
+   CDD = (status >> 4) & 0xf;
+  
+   switch ( ATN ) 
+   {
+      case 0x0:
+                 break;  /* go on to CDD stuff */
+      case SONY535_ATN_BUSY:
+                 if ( initialized )
+                    printk("Sony CDROM error, drive busy\n");
+                 return( CD_BUSY);
+      case SONY535_ATN_EJECT_IN_PROGRESS:
+                 printk("Sony CDROM error, eject in progress\n");
+                 sony_audio_status = CDROM_AUDIO_INVALID;
+                 return( CD_BUSY);
+      case SONY535_ATN_RESET_OCCURRED:
+      case SONY535_ATN_DISC_CHANGED:
+      case SONY535_ATN_RESET_AND_DISC_CHANGED:
+#ifdef DEBUG
+                 printk("Sony CDROM, reset occurred or disc changed\n");
+#endif
+                 sony_disc_changed = 1;
+                 sony_toc_read = 0;
+                 sony_audio_status = CDROM_AUDIO_NO_STATUS;
+                 sony_first_block = -1;
+                 sony_last_block = -1;
+                 if (initialized)
+                 {
+                    cmd = SONY535_SPIN_UP;
+                    do_sony_cmd( &cmd,1, e_status, NULL,0, 0 );
+                    sony_get_toc();
+                 }
+                 return( 0 );
+      default:
+                 printk("Sony CDROM error, drive busy (ATN=0x%x)\n", ATN );
+                 return( CD_BUSY );
+   }
+   switch ( CDD ) 
+   {  /* the 531 docs are not helpful in decoding this */
+      case 0x0:       /* just use the values from the DOS driver */
+      case 0x2:
+      case 0xa:
+                 break;  /* no error */
+      case 0xc:
+                 printk("check_drive_status(): CDD = 0xc! Not properly handled!\n");
+                 return( CD_BUSY );  /* ? */
+      default:
+                 return( CD_BUSY );
+   }
+   return( 0 );
+}  /* check_drive_status() */
+
+/*****************************************************************************
+ * int do_sony_cmd( Byte *cmd, int n_cmd, Byte status[2], 
+ *                Byte *response, int n_response, int ignore_status_bit7 )
+ *
+ *  Generic routine for executing commands.  The command and its parameters
+ *  should be placed in the cmd[] array, number of bytes in the command is
+ *  stored in nCmd.  The response from the command will be stored in the
+ *  response array.  The number of bytes you expect back (excluding status)
+ *  should be passed in nReponse.  Finally, some
+ *  commands set bit 7 of the return status even when there is no second
+ *  status byte, on these commands set ignoreStatusBit7 TRUE.
+ *    If the command was sent and data recieved back, then we return 0,
+ *  else we return TIME_OUT.  You still have to check the status yourself.
+ *    You should call check_drive_status() before calling this routine
+ *  so that you do not lose notifications of disk changes, etc.
+ ****************************************************************************/
+static int 
+do_sony_cmd( Byte *cmd, int n_cmd, Byte status[2], 
+             Byte *response, int n_response, int ignore_status_bit7 )
+{
+   int i;
+  
+    /* write out the command */
+   for ( i=0; i < n_cmd; i++ )
+      outb( cmd[i], command_reg );
+  
+    /* read back the status */
+   if ( read_result_reg( status ) != 0 )
+      return( TIME_OUT );
+   if ( !ignore_status_bit7 && ((status[0] & 0x80) != 0) ) /* get second status byte */
+   {
+      if ( read_result_reg( status+1 ) != 0 )
+         return( TIME_OUT );
+   }
+   else
+   {
+      status[1] = 0;
+   }
+    
+   /* do not know about when I should read set of data and when not to */
+   if ( (status[0] & ((ignore_status_bit7 ? 0x7f : 0xff) & 0x8f)) != 0 )
+      return( 0 );
+  
+    /* else, read in rest of data */
+   for ( i=0; n_response > 0; n_response--, i++ )
+      if ( read_result_reg( response+i ) != 0 ) return(TIME_OUT);
+   return( 0 );
+}  /* do_sony_cmd() */
+
+/**************************************************************************
+ * int set_drive_mode( int mode, Byte status[2] )
+ *
+ *  Set the drive mode to the specified value (mode=0 is audio, mode=e0
+ * is mode-1 CDROM
+ **************************************************************************/
+static int 
+set_drive_mode( int mode, Byte status[2] )
+{
+   Byte cmd_buff[2], ret_buff[1];
+  
+   cmd_buff[0] = SONY535_SET_DRIVE_MODE;
+   cmd_buff[1] = mode;
+   return( do_sony_cmd( cmd_buff,2, status, ret_buff,1, 1 ) );
+}  /* set_drive_mode() */
+
+/***************************************************************************
+ * int seek_and_read_N_blocks( Byte params[], int n_blocks, Byte status[2], 
+ *                             Byte *data_buff, int buff_size )
+ *
+ *  Read n_blocks of data from the CDROM starting at position params[0:2],
+ *  number of blocks in stored in params[3:5] -- both these are already
+ *  int bcd format.
+ *  Transfer the data into the buffer pointed at by data_buff.  buff_size
+ *  gives the number of bytes available in the buffer.
+ *    The routine returns number of bytes read in if successful, otherwise
+ *  it returns one of the standard error returns.
+ ***************************************************************************/
+static int 
+seek_and_read_N_blocks( Byte params[], int n_blocks, Byte status[2],
+                        Byte *data_buff, int buf_size )
+{
+   int i;
+   const int block_size = 2048;
+   Byte cmd_buff[7];
+   int read_status;
+   Byte *start_pos = data_buff;
+   int retry_count;
+  
+   if ( ((long)block_size)*n_blocks > buf_size )
+      return( NO_ROOM );
+  
+   set_drive_mode( SONY535_CDROM_DRIVE_MODE, status );
+  
+    /* send command to read the data */
+   cmd_buff[0] = SONY535_SEEK_AND_READ_N_BLOCKS_1;
+   for ( i=0; i < 6; i++ )
+      cmd_buff[i+1] = params[i];
+   for ( i=0; i < 7; i++ )
+      outb( cmd_buff[i], command_reg );
+  
+    /* read back the data one block at a time */
+   while ( n_blocks-- > 0 ) 
+   {
+       /* wait for data to be ready */
+      retry_count = jiffies + SONY_JIFFIES_TIMEOUT;
+      while ( retry_count > jiffies ) 
+      {
+         read_status = inb(read_status_reg);
+         if ( (read_status & SONY535_RESULT_NOT_READY_BIT) == 0 ) 
+         {
+            read_exec_status( status );
+            return( BAD_STATUS );
+         }
+         if ( (read_status & SONY535_DATA_NOT_READY_BIT) == 0 ) 
+         {
+             /* data is ready, read it */
+            for ( i=0; i < block_size; i++ )
+               *data_buff++ = inb( data_reg );  /* unrolling this loop does not seem to help */
+            break;  /* exit the timeout loop */
+         }
+         sony_sleep();  /* data not ready, sleep a while */
+      }
+      if ( retry_count <= jiffies )
+      return( TIME_OUT );  /* if we reach this stage */
+   }
+  
+    /* read all the data, now read the status */
+   if ( (i=read_exec_status( status )) != 0 )
+      return( i );
+   return( data_buff - start_pos );
+}  /* seek_and_read_N_blocks() */
+
+/****************************************************************************
+ * int request_toc_data( Byte status[2], struct s535_sony_toc *toc )
+ *
+ *  Read in the table of contents data.  Converts all the bcd data
+ * into integers in the toc structure.
+ ****************************************************************************/
+static int 
+request_toc_data( Byte status[2], struct s535_sony_toc *toc )
+{
+   int to_status;
+   int i, j, n_tracks, track_no;
+   Byte cmd_no = 0xb2;
+   Byte track_address_buffer[5];
+   int first_track_num, last_track_num;
+
+    /* read the fixed portion of the table of contents */
+   if ((to_status=do_sony_cmd( &cmd_no,1, status, (Byte *)toc,15, 1 )) != 0 )
+      return( to_status );
+  
+    /* convert the data into integers so we can use them */
+   first_track_num = bcd_to_int(toc->first_track_num);
+   last_track_num = bcd_to_int(toc->last_track_num);
+   n_tracks = last_track_num - first_track_num + 1;
+  
+    /* read each of the track address descriptors */
+   for ( i=0; i < n_tracks; i++ ) 
+   {
+       /* read the descriptor into a temporary buffer */
+      for ( j=0; j < 5; j++ ) 
+      {
+         if ( read_result_reg( track_address_buffer+j ) != 0 )
+            return( TIME_OUT );
+         if ( j == 1 )  /* need to convert from bcd */
+            track_no = bcd_to_int(track_address_buffer[j]);
+      }
+       /* copy the descriptor to proper location - sonycd.c just fills */
+      memcpy( toc->tracks+i, track_address_buffer, 5 );
+   }
+   return( 0 );
+}  /* request_toc_data() */
+
+/***************************************************************************
+ * int spin_up_drive( Byte status[2] )
+ *
+ *  Spin up the drive (unless it is already spinning).
+ ***************************************************************************/
+static int 
+spin_up_drive( Byte status[2] )
+{
+   Byte cmd_buff[1];
+  
+    /* first see if the drive is already spinning */
+   cmd_buff[0] = SONY535_REQUEST_DRIVE_STATUS_1;
+   if ( do_sony_cmd( cmd_buff,1, status, NULL,0, 0 ) != 0 )
+      return(TIME_OUT );
+   if ( (status[0] & SONY535_STATUS1_NOT_SPINNING) == 0 )
+      return( 0 );  /* its already spinning */
+  
+    /* else, give the spin-up command */
+   cmd_buff[0] = SONY535_SPIN_UP;
+   return( do_sony_cmd( cmd_buff, 1, status, NULL,0, 0 )  );
+}  /* spin_up_drive() */
+
+/*--------------------end of SONY CDU535 very specific ---------------------*/
+
+/* Convert from an integer 0-99 to BCD */
+static inline unsigned int
+int_to_bcd(unsigned int val)
+{
+   int retval;
+
+
+   retval = (val / 10) << 4;
+   retval = retval | val % 10;
+   return(retval);
+}
+
+
+/* Convert from BCD to an integer from 0-99 */
+static unsigned int
+bcd_to_int(unsigned int bcd)
+{
+   return((((bcd >> 4) & 0x0f) * 10) + (bcd & 0x0f));
+}
+
+
+/*
+ * Convert a logical sector value (like the OS would want to use for
+ * a block device) to an MSF format.
+ */
+static void
+log_to_msf(unsigned int log, unsigned char *msf)
+{
+   log = log + LOG_START_OFFSET;
+   msf[0] = int_to_bcd(log / 4500);
+   log = log % 4500;
+   msf[1] = int_to_bcd(log / 75);
+   msf[2] = int_to_bcd(log % 75);
+}
+
+
+/*
+ * Convert an MSF format to a logical sector.
+ */
+static unsigned int
+msf_to_log(unsigned char *msf)
+{
+   unsigned int log;
+
+
+   log = bcd_to_int(msf[2]);
+   log += bcd_to_int(msf[1]) * 75;
+   log += bcd_to_int(msf[0]) * 4500;
+   log = log - LOG_START_OFFSET;
+
+   return log;
+}
+
+
+/*
+ * Take in integer size value and put it into a buffer like
+ * the drive would want to see a number-of-sector value.
+ */
+static void
+size_to_buf(unsigned int size,
+            unsigned char *buf)
+{
+   buf[0] = size / 65536;
+   size = size % 65536;
+   buf[1] = size / 256;
+   buf[2] = size % 256;
+}
+
+
+/*
+ * The OS calls this to perform a read or write operation to the drive.
+ * Write obviously fail.  Reads to a read ahead of sony_buffer_size
+ * bytes to help speed operations.  This especially helps since the OS
+ * uses 1024 byte blocks and the drive uses 2048 byte blocks.  Since most
+ * data access on a CD is done sequentially, this saves a lot of operations.
+ */
+static void
+do_scd535_request(void)
+{
+   int block;
+   unsigned int dev;
+   int nsect;
+   unsigned char params[10];
+   int copyoff;
+   int spin_up_retry;
+   unsigned int read_size;
+   unsigned char status[2], cmd[2];
+
+
+   if ( !sony_inuse )
+   {
+      scd_open( NULL, NULL );
+   }
+   
+   while (1)
+   {
+      /*
+       * The beginning here is stolen from the hard disk driver.  I hope
+       * its right.
+       */
+      if (!(CURRENT) || CURRENT->dev < 0)
+      {
+         return;
+      }
+
+      INIT_REQUEST;
+      dev = MINOR(CURRENT->dev);
+      block = CURRENT->sector;
+      nsect = CURRENT->nr_sectors;
+      if (dev != 0)
+      {
+         end_request(0);
+         continue;
+      }
+
+      switch(CURRENT->cmd)
+      {
+      case READ:
+         /*
+          * If the block address is invalid or the request goes beyond the end of
+          * the media, return an error.
+          */
+         if ((block / 4) >= sony_toc->lead_out_start_lba)
+         {
+            end_request(0);
+            return;
+         }
+         if (((block + nsect) / 4) >= sony_toc->lead_out_start_lba)
+         {
+            end_request(0);
+            return;
+         }
+
+         while (nsect > 0)
+         {
+            /*
+             * If the requested sector is not currently in the read-ahead buffer,
+             * it must be read in.
+             */
+            if ((block < sony_first_block) || (block > sony_last_block))
+            {
+               sony_first_block = (block / 4) * 4;
+               log_to_msf(block/4, params);
+
+               /*
+                * If the full read-ahead would go beyond the end of the media, trim
+                * it back to read just till the end of the media.
+                */
+               if (((block / 4) + sony_buffer_sectors) >= sony_toc->lead_out_start_lba)
+               {
+                  sony_last_block = (sony_toc->lead_out_start_lba * 4) - 1;
+                  read_size = sony_toc->lead_out_start_lba - (block / 4);
+               }
+               else
+               {
+                  sony_last_block = sony_first_block + (sony_buffer_sectors * 4) - 1;
+                  read_size = sony_buffer_sectors;
+               }
+               size_to_buf(read_size, &params[3]);
+
+               /*
+                * Read the data.  If the drive was not spinning, spin it up and try
+                * once more.  I know, the goto is ugly, but I am too lazy to fix it.
+                */
+               spin_up_retry = 0;
+try_read_again:
+#if 0
+               if ( check_drive_status() != 0 ) {  /* drive not ready */
+                  sony_first_block = -1;
+                  sony_last_block = -1;
+                  end_request(0);
+                  return;
+                  }
+#endif
+               if ( seek_and_read_N_blocks( params, read_size, status, sony_buffer,
+                         (read_size * 2048) ) < 0 ) {
+                  if ((status[0] & SONY535_STATUS1_NOT_SPINNING) && (!spin_up_retry))
+                  {
+                     printk(" Sony535 Debug -- calling spin up when reading data!\n");
+                     cmd[0] = SONY535_SPIN_UP;
+                     do_sony_cmd( cmd,1, status, NULL,0, 0);
+                     spin_up_retry = 1;
+                     goto try_read_again;
+                  }
+
+                  printk("Sony CDROM Read error: 0x%.2x\n", status[0]);
+                  sony_first_block = -1;
+                  sony_last_block = -1;
+                  end_request(0);
+                  return;
+               }
+            }
+   
+            /*
+             * The data is in memory now, copy it to the buffer and advance to the
+             * next block to read.
+             */
+            copyoff = (block - sony_first_block) * 512;
+            memcpy(CURRENT->buffer, sony_buffer+copyoff, 512);
+               
+            block += 1;
+            nsect -= 1;
+            CURRENT->buffer += 512;
+         }
+               
+         end_request(1);
+         break;
+            
+      case WRITE:
+         end_request(0);
+         break;
+            
+      default:
+         panic("Unkown SONY CD cmd");
+      }
+   }
+}
+
+
+/*
+ * Read the table of contents from the drive and set sony_toc_read if
+ * successful.
+ */
+static void
+sony_get_toc(void)
+{
+   unsigned char status[2];
+  
+   if ( !sony_toc_read ) 
+   {
+       /* do not call check_drive_status() from here since it can call this routine */
+      if ( request_toc_data( status, sony_toc ) < 0 )
+         return;
+      sony_toc->lead_out_start_lba = msf_to_log(sony_toc->lead_out_start_msf);
+      sony_toc_read = 1;
+   }
+}
+
+
+/*
+ * Search for a specific track in the table of contents.  track is
+ * passed in bcd format
+ */
+static int
+find_track(int track)
+{
+   int i;
+   int num_tracks;
+
+
+   num_tracks = bcd_to_int(sony_toc->last_track_num) - 
+                   bcd_to_int(sony_toc->first_track_num) + 1;
+   for (i = 0; i < num_tracks; i++)
+   {
+      if (sony_toc->tracks[i].track == track)
+      {
+         return i;
+      }
+   }
+
+   return -1;
+}
+
+/*
+ * Read the subcode and put it int last_sony_subcode for future use.
+ */
+static int
+read_subcode(void)
+{
+   Byte cmd = SONY535_REQUEST_SUB_Q_DATA, status[2];
+   int dsc_status;
+   
+   if ( check_drive_status() != 0 )
+      return( -EIO );
+     
+   if ( (dsc_status=do_sony_cmd( &cmd,1, status, (Byte *)last_sony_subcode, 
+                      sizeof(struct s535_sony_subcode), 1 )) != 0 ) 
+   {
+      printk("Sony CDROM error 0x%.2x, %d (read_subcode)\n", status[0], 
+              dsc_status );
+      return( -EIO );
+   }
+   return(0);
+}
+
+
+/*
+ * Get the subchannel info like the CDROMSUBCHNL command wants to see it.  If
+ * the drive is playing, the subchannel needs to be read (since it would be
+ * changing).  If the drive is paused or completed, the subcode information has
+ * already been stored, just use that.  The ioctl call wants things in decimal
+ * (not BCD), so all the conversions are done.
+ */
+static int
+sony_get_subchnl_info(long arg)
+{
+   struct cdrom_subchnl schi;
+
+
+   /* Get attention stuff */
+   if ( check_drive_status() != 0 )
+      return( -EIO );
+
+   sony_get_toc();
+   if (!sony_toc_read)
+   {
+      return -EIO;
+   }
+
+   verify_area(VERIFY_WRITE /* and read */, (char *) arg, sizeof(schi));
+
+   memcpy_fromfs(&schi, (char *) arg, sizeof(schi));
+   
+   switch (sony_audio_status)
+   {
+   case CDROM_AUDIO_PLAY:
+      if (read_subcode() < 0)
+      {
+         return -EIO;
+      }
+      break;
+
+   case CDROM_AUDIO_PAUSED:
+   case CDROM_AUDIO_COMPLETED:
+      break;
+
+   case CDROM_AUDIO_NO_STATUS:
+      schi.cdsc_audiostatus = sony_audio_status;
+      memcpy_tofs((char *) arg, &schi, sizeof(schi));
+      return 0;
+      break;
+
+   case CDROM_AUDIO_INVALID:
+   case CDROM_AUDIO_ERROR:
+   default:
+      return -EIO;
+   }
+
+   schi.cdsc_audiostatus = sony_audio_status;
+   schi.cdsc_adr = last_sony_subcode->address;
+   schi.cdsc_ctrl = last_sony_subcode->control;
+   schi.cdsc_trk = bcd_to_int(last_sony_subcode->track_num);
+   schi.cdsc_ind = bcd_to_int(last_sony_subcode->index_num);
+   if (schi.cdsc_format == CDROM_MSF)
+   {
+      schi.cdsc_absaddr.msf.minute = bcd_to_int(last_sony_subcode->abs_msf[0]);
+      schi.cdsc_absaddr.msf.second = bcd_to_int(last_sony_subcode->abs_msf[1]);
+      schi.cdsc_absaddr.msf.frame = bcd_to_int(last_sony_subcode->abs_msf[2]);
+
+      schi.cdsc_reladdr.msf.minute = bcd_to_int(last_sony_subcode->rel_msf[0]);
+      schi.cdsc_reladdr.msf.second = bcd_to_int(last_sony_subcode->rel_msf[1]);
+      schi.cdsc_reladdr.msf.frame = bcd_to_int(last_sony_subcode->rel_msf[2]);
+   }
+   else if (schi.cdsc_format == CDROM_LBA)
+   {
+      schi.cdsc_absaddr.lba = msf_to_log(last_sony_subcode->abs_msf);
+      schi.cdsc_reladdr.lba = msf_to_log(last_sony_subcode->rel_msf);
+   }
+   
+   memcpy_tofs((char *) arg, &schi, sizeof(schi));
+   return 0;
+}
+
+
+/*
+ * The big ugly ioctl handler.
+ */
+static int
+scd_ioctl(struct inode *inode,
+          struct file  *file,
+          unsigned int cmd,
+          unsigned long arg)
+{
+   unsigned int dev;
+   unsigned char status[2];
+   unsigned char cmd_buff[10], params[10];
+   int i, dsc_status;
+
+
+   if (!inode)
+   {
+      return -EINVAL;
+   }
+   dev = MINOR(inode->i_rdev) >> 6;
+   if (dev != 0)
+   {
+      return -EINVAL;
+   }
+   
+   if ( check_drive_status() != 0 )
+      return( -EIO );
+
+   switch (cmd)
+   {
+   case CDROMSTART:     /* Spin up the drive */
+      if ( spin_up_drive( status ) < 0 )
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMSTART)\n", status[0]);
+         return -EIO;
+      }
+      return 0;
+      break;
+      
+   case CDROMSTOP:      /* Spin down the drive */
+      cmd_buff[0] = SONY535_HOLD;
+      do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+
+      /*
+       * Spin the drive down, ignoring the error if the disk was
+       * already not spinning.
+       */
+      sony_audio_status = CDROM_AUDIO_NO_STATUS;
+      cmd_buff[0] = SONY535_SPIN_DOWN;
+      dsc_status = do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+      if ( (( dsc_status < 0 ) && (dsc_status != BAD_STATUS)) ||
+           ( (status[0] & ~(SONY535_STATUS1_NOT_SPINNING)) != 0) ) 
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMSTOP)\n", status[0]);
+         return -EIO;
+      }
+      
+      return 0;
+      break;
+
+   case CDROMPAUSE:     /* Pause the drive */
+      cmd_buff[0] = SONY535_HOLD;  /* CDU-31 driver uses AUDIO_STOP, not pause */
+      if ( do_sony_cmd( cmd_buff,1, status, NULL,0, 0 ) != 0 ) 
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMPAUSE)\n", status[0]);
+         return -EIO;
+      }
+
+      /* Get the current position and save it for resuming */
+      if (read_subcode() < 0)
+      {
+         return -EIO;
+      }
+      cur_pos_msf[0] = last_sony_subcode->abs_msf[0];
+      cur_pos_msf[1] = last_sony_subcode->abs_msf[1];
+      cur_pos_msf[2] = last_sony_subcode->abs_msf[2];
+      sony_audio_status = CDROM_AUDIO_PAUSED;
+      return 0;
+      break;
+
+   case CDROMRESUME:    /* Start the drive after being paused */
+      set_drive_mode( SONY535_AUDIO_DRIVE_MODE, status );
+      
+      if (sony_audio_status != CDROM_AUDIO_PAUSED)
+      {
+         return -EINVAL;
+      }
+      
+      spin_up_drive( status );
+      
+      /* Start the drive at the saved position. */
+      cmd_buff[0] = SONY535_PLAY_AUDIO;
+      cmd_buff[1] = 0;  /* play back starting at this address */
+      cmd_buff[2] = cur_pos_msf[0];
+      cmd_buff[3] = cur_pos_msf[1];
+      cmd_buff[4] = cur_pos_msf[2];
+      cmd_buff[5] = SONY535_PLAY_AUDIO;
+      cmd_buff[6] = 2;  /* set ending address */
+      cmd_buff[7] = final_pos_msf[0];
+      cmd_buff[8] = final_pos_msf[1];
+      cmd_buff[9] = final_pos_msf[2];
+      if ( (do_sony_cmd( cmd_buff,5, status, NULL,0, 0 ) != 0 ) ||
+           (do_sony_cmd( cmd_buff+5,5, status, NULL,0, 0 ) != 0 ) )
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMRESUME)\n", status[0]);
+         return -EIO;
+      }
+      sony_audio_status = CDROM_AUDIO_PLAY;
+      return 0;
+      break;
+
+   case CDROMPLAYMSF:   /* Play starting at the given MSF address. */
+      verify_area(VERIFY_READ, (char *) arg, 6);
+      spin_up_drive( status );
+      set_drive_mode( SONY535_AUDIO_DRIVE_MODE, status );
+      memcpy_fromfs(params, (void *) arg, 6);
+      
+      /* The parameters are given in int, must be converted */
+      for (i=0; i<3; i++)
+      {
+         cmd_buff[2+i] = int_to_bcd(params[i]);
+         cmd_buff[7+i] = int_to_bcd(params[i+3]);
+      }
+      cmd_buff[0] = SONY535_PLAY_AUDIO;
+      cmd_buff[1] = 0;  /* play back starting at this address */
+       /* cmd_buff[2-4] are filled in for loop above */
+      cmd_buff[5] = SONY535_PLAY_AUDIO;
+      cmd_buff[6] = 2;  /* set ending address */
+       /* cmd_buff[7-9] are filled in for loop above */
+      if ( (do_sony_cmd( cmd_buff,5, status, NULL,0, 0 ) != 0 ) ||
+           (do_sony_cmd( cmd_buff+5,5, status, NULL,0, 0 ) != 0 ) )
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMPLAYMSF)\n", status[0]);
+         return -EIO;
+      }
+      
+      /* Save the final position for pauses and resumes */
+      final_pos_msf[0] = cmd_buff[7];
+      final_pos_msf[1] = cmd_buff[8];
+      final_pos_msf[2] = cmd_buff[9];
+      sony_audio_status = CDROM_AUDIO_PLAY;
+      return 0;
+      break;
+
+   case CDROMREADTOCHDR:        /* Read the table of contents header */
+      {
+         struct cdrom_tochdr *hdr;
+         struct cdrom_tochdr loc_hdr;
+         
+         sony_get_toc();
+         if (!sony_toc_read)
+         {
+            return -EIO;
+         }
+         
+         hdr = (struct cdrom_tochdr *) arg;
+         verify_area(VERIFY_WRITE, hdr, sizeof(*hdr));
+         loc_hdr.cdth_trk0 = bcd_to_int(sony_toc->first_track_num);
+         loc_hdr.cdth_trk1 = bcd_to_int(sony_toc->last_track_num);
+         memcpy_tofs(hdr, &loc_hdr, sizeof(*hdr));
+      }
+      return 0;
+      break;
+
+   case CDROMREADTOCENTRY:      /* Read a given table of contents entry */
+      {
+         struct cdrom_tocentry *entry;
+         struct cdrom_tocentry loc_entry;
+         int track_idx;
+         unsigned char *msf_val = NULL;
+         
+         sony_get_toc();
+         if (!sony_toc_read)
+         {
+            return -EIO;
+         }
+         
+         entry = (struct cdrom_tocentry *) arg;
+         verify_area(VERIFY_WRITE /* and read */, entry, sizeof(*entry));
+         
+         memcpy_fromfs(&loc_entry, entry, sizeof(loc_entry));
+         
+         /* Lead out is handled separately since it is special. */
+         if (loc_entry.cdte_track == CDROM_LEADOUT)
+         {
+            loc_entry.cdte_adr = 0 /*sony_toc->address2*/;
+            loc_entry.cdte_ctrl = sony_toc->control2;
+            msf_val = sony_toc->lead_out_start_msf;
+         }
+         else
+         {
+            track_idx = find_track(int_to_bcd(loc_entry.cdte_track));
+            if (track_idx < 0)
+            {
+               return -EINVAL;
+            }
+            
+            loc_entry.cdte_adr = 0 /*sony_toc->tracks[track_idx].address*/;
+            loc_entry.cdte_ctrl = sony_toc->tracks[track_idx].control;
+            msf_val = sony_toc->tracks[track_idx].track_start_msf;
+         }
+         
+         /* Logical buffer address or MSF format requested? */
+         if (loc_entry.cdte_format == CDROM_LBA)
+         {
+            loc_entry.cdte_addr.lba = msf_to_log(msf_val);
+         }
+         else if (loc_entry.cdte_format == CDROM_MSF)
+         {
+            loc_entry.cdte_addr.msf.minute = bcd_to_int(*msf_val);
+            loc_entry.cdte_addr.msf.second = bcd_to_int(*(msf_val+1));
+            loc_entry.cdte_addr.msf.frame = bcd_to_int(*(msf_val+2));
+         }
+         memcpy_tofs(entry, &loc_entry, sizeof(*entry));
+      }
+      return 0;
+      break;
+
+   case CDROMPLAYTRKIND:     /* Play a track.  This currently ignores index. */
+      {
+         struct cdrom_ti ti;
+         int track_idx;
+         
+         sony_get_toc();
+         if (!sony_toc_read)
+         {
+            return -EIO;
+         }
+         
+         verify_area( VERIFY_READ, (char *) arg, sizeof(ti));
+         
+         memcpy_fromfs(&ti, (char *) arg, sizeof(ti));
+         if (   (ti.cdti_trk0 < sony_toc->first_track_num)
+             || (ti.cdti_trk0 > sony_toc->last_track_num)
+             || (ti.cdti_trk1 < ti.cdti_trk0))
+         {
+            return -EINVAL;
+         }
+         
+         track_idx = find_track(int_to_bcd(ti.cdti_trk0));
+         if (track_idx < 0)
+         {
+            return -EINVAL;
+         }
+         params[1] = sony_toc->tracks[track_idx].track_start_msf[0];
+         params[2] = sony_toc->tracks[track_idx].track_start_msf[1];
+         params[3] = sony_toc->tracks[track_idx].track_start_msf[2];
+         /*
+          * If we want to stop after the last track, use the lead-out
+          * MSF to do that.
+          */
+         if (ti.cdti_trk1 >= bcd_to_int(sony_toc->last_track_num))
+         {
+            log_to_msf(msf_to_log(sony_toc->lead_out_start_msf)-1,
+                       &(params[4]));
+         }
+         else
+         {
+            track_idx = find_track(int_to_bcd(ti.cdti_trk1+1));
+            if (track_idx < 0)
+            {
+               return -EINVAL;
+            }
+            log_to_msf(msf_to_log(sony_toc->tracks[track_idx].track_start_msf)-1,
+                       &(params[4]));
+         }
+         params[0] = 0x03;
+         
+         spin_up_drive( status );
+         
+         set_drive_mode( SONY535_AUDIO_DRIVE_MODE, status );
+      
+         /* Start the drive at the saved position. */
+         cmd_buff[0] = SONY535_PLAY_AUDIO;
+         cmd_buff[1] = 0;  /* play back starting at this address */
+         cmd_buff[2] = params[1];
+         cmd_buff[3] = params[2];
+         cmd_buff[4] = params[3];
+         cmd_buff[5] = SONY535_PLAY_AUDIO;
+         cmd_buff[6] = 2;  /* set ending address */
+         cmd_buff[7] = params[4];
+         cmd_buff[8] = params[5];
+         cmd_buff[9] = params[6];
+         if ( (do_sony_cmd( cmd_buff,5, status, NULL,0, 0 ) != 0 ) ||
+              (do_sony_cmd( cmd_buff+5,5, status, NULL,0, 0 ) != 0 ) )
+         {
+            printk("Params: %x %x %x %x %x %x %x\n", params[0], params[1],
+                   params[2], params[3], params[4], params[5], params[6]);
+            printk("Sony CDROM error 0x%.2x (CDROMPLAYTRKIND)\n", status[0]);
+            return -EIO;
+         }
+         
+         /* Save the final position for pauses and resumes */
+         final_pos_msf[0] = params[4];
+         final_pos_msf[1] = params[5];
+         final_pos_msf[2] = params[6];
+         sony_audio_status = CDROM_AUDIO_PLAY;
+         return 0;
+      }
+     
+   case CDROMSUBCHNL:   /* Get subchannel info */
+      return sony_get_subchnl_info(arg);
+
+   case CDROMVOLCTRL:   /* Volume control.  What volume does this change, anyway? */
+      {
+         struct cdrom_volctrl volctrl;
+         
+         verify_area(VERIFY_READ, (char *) arg, sizeof(volctrl));
+         
+         memcpy_fromfs(&volctrl, (char *) arg, sizeof(volctrl));
+         cmd_buff[0] = SONY535_SET_VOLUME;
+         cmd_buff[1] = volctrl.channel0;
+         cmd_buff[2] = volctrl.channel1;
+         if ( do_sony_cmd( cmd_buff,3, status, NULL,0, 0 ) != 0 )
+         {
+            printk("Sony CDROM error 0x%.2x (CDROMVOLCTRL)\n", status[0]);
+            return -EIO;
+         }
+      }
+      return 0;
+
+   case CDROMEJECT:     /* Eject the drive */
+      cmd_buff[0] = SONY535_STOP;
+      do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+      cmd_buff[0] = SONY535_SPIN_DOWN;
+      do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+
+      sony_audio_status = CDROM_AUDIO_INVALID;
+      cmd_buff[0] = SONY535_EJECT_CADDY;
+      if ( do_sony_cmd( cmd_buff,1, status, NULL,0, 0 ) != 0 )
+      {
+         printk("Sony CDROM error 0x%.2x (CDROMEJECT)\n", status[0]);
+         return -EIO;
+      }
+      return 0;
+      break;
+     
+   default:
+      return -EINVAL;
+   }
+}
+
+
+/*
+ * Open the drive for operations.  Spin the drive up and read the table of
+ * contents if these have not already been done.
+ */
+static int
+scd_open(struct inode *inode,
+         struct file *filp)
+{
+   unsigned char status[2], cmd_buff[2];
+
+
+   if ( sony_inuse )
+   {
+      return( -EBUSY );
+   }
+   
+   if ( check_drive_status() != 0 )
+   {
+      return( -EIO );
+   }
+      
+   sony_inuse = 1;
+   
+   if ( spin_up_drive( status ) != 0 )
+   {
+      printk("Sony CDROM error 0x%.2x (scd_open, spin up)\n", status[0]);
+      sony_inuse = 0;
+      return -EIO;
+   }
+      
+#if 0  /* what is this doing - CDU-535 does not have separate READ and REQ_TOC */
+   do_sony_cd_cmd(SONY_READ_TOC_CMD, NULL, 0, res_reg, &res_size);
+   if ((res_size < 2) || (res_reg[0] != 0))
+   {
+      /* If the drive is already playing, its ok. */
+      if (res_reg[1] == SONY_AUDIO_PLAYING_ERR)
+      {
+         goto drive_spinning;
+      }
+
+      printk("Sony CDROM error 0x%.2x (scd_open, read toc)\n", res_reg[1]);
+      do_sony_cd_cmd(SONY_SPIN_DOWN_CMD, NULL, 0, res_reg, &res_size);
+      
+      sony_inuse = 0;
+      return -EIO;
+   }
+#endif
+
+   sony_get_toc();
+   if (!sony_toc_read)
+   {
+      cmd_buff[0] = SONY535_SPIN_DOWN;
+      do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+      sony_inuse = 0;
+      return -EIO;
+   }
+      
+#if 0  /* not used without stuff read toc above */
+drive_spinning:
+#endif
+
+   if ( inode ) 
+   {
+      check_disk_change(inode->i_rdev);
+   }
+
+   sony_usage++;
+   
+#ifdef LOCK_DOORS
+    /* disable the eject button while mounted */
+   cmd_buff[0] = SONY535_DISABLE_EJECT_BUTTON;
+   do_sony_cmd( cmd_buff,1, status, NULL,0, 0 );
+#endif
+
+   return 0;
+}
+
+
+/*
+ * Close the drive.  Spin it down if no task is using it.  The spin
+ * down will fail if playing audio, so audio play is OK.
+ */
+static void
+scd_release(struct inode *inode,
+         struct file *filp)
+{
+   unsigned char status[2], cmd_no;
+
+   sony_inuse = 0;
+
+   if (sony_usage > 0)
+   {
+      sony_usage--;
+   }
+   if (sony_usage == 0)
+   {
+      sync_dev(inode->i_rdev);
+      check_drive_status();
+
+      if ( sony_audio_status != CDROM_AUDIO_PLAY ) {
+         cmd_no = SONY535_SPIN_DOWN;
+         do_sony_cmd( &cmd_no,1, status, NULL,0, 0 );
+         }
+#ifdef LOCK_DOORS
+       /* enable the eject button after umount */
+      cmd_no = SONY535_ENABLE_EJECT_BUTTON;
+      do_sony_cmd( &cmd_no,1, status, NULL,0, 0 );
+#endif
+   }
+}
+
+
+static struct file_operations scd_fops = {
+   NULL,                   /* lseek - default */
+   block_read,             /* read - general block-dev read */
+   block_write,            /* write - general block-dev write */
+   NULL,                   /* readdir - bad */
+   NULL,                   /* select */
+   scd_ioctl,              /* ioctl */
+   NULL,                   /* mmap */
+   scd_open,               /* open */
+   scd_release             /* release */
+};
+
+
+/*
+ * Initialize the driver.
+ */
+unsigned long
+init_sony535(unsigned long mem_start, unsigned long mem_end)
+{
+   struct s535_sony_drive_config drive_config;
+   unsigned char cmd_buff[3], ret_buff[2];
+   unsigned char status[2];
+   int retry_count;
+
+
+   /* Set up all the register locations */
+   result_reg = sony_cd_base_io;
+   command_reg = sony_cd_base_io;
+   data_reg = sony_cd_base_io + 1;
+   read_status_reg = sony_cd_base_io + 2;
+   select_unit_reg = sony_cd_base_io + 3;
+
+    /* look for the CD-ROM, follows the procedure in the DOS driver */
+   inb( select_unit_reg );
+   retry_count = jiffies + 2*HZ;
+   while ( retry_count > jiffies )
+      sony_sleep();		/* wait for 40 18 Hz ticks (from DOS driver) */
+   inb( result_reg );
+   
+   outb( 0, read_status_reg );	/* does a reset? */
+   retry_count = jiffies + SONY_JIFFIES_TIMEOUT;
+   while ( retry_count > jiffies ) 
+   {
+      select_unit(0);
+      if ( inb( result_reg ) != 0xff )
+         break;
+      sony_sleep();  /* about 1-2 ms on my machine */
+   }
+   
+   if ( (retry_count > jiffies) && (check_drive_status() != TIME_OUT) ) 
+   {  
+       /* CD-ROM drive responded --  get the drive configuration */
+      cmd_buff[0] = SONY535_INQUIRY;
+      if ( do_sony_cmd( cmd_buff,1, status, (Byte *)&drive_config, 28, 1) == 0 ) 
+      {
+          /* was able to get the configuration, set drive mode as rest of init */
+         if ( (status[0] & 0x7f) != 0 )
+            printk("Inquiry command returned status = 0x%x\n",status[0]);
+         cmd_buff[0] = SONY535_SET_DRIVE_MODE;
+         cmd_buff[1] = 0x0;  /* default audio */
+         if (do_sony_cmd( cmd_buff,2, status, ret_buff,1, 1 ) == 0 ) 
+         {
+             /* set the drive mode successful, we are set! */
+            sony_buffer_size = SONY535_BUFFER_SIZE;
+            sony_buffer_sectors = sony_buffer_size / 2048;
+
+            printk("Sony I/F CDROM : %8.8s %16.16s %4.4s",
+                   drive_config.vendor_id,
+                   drive_config.product_id,
+                   drive_config.product_rev_level );
+            printk("  using %d byte buffer\n", sony_buffer_size);
+
+	    if (register_blkdev(MAJOR_NR,"scd",&scd_fops)) {
+		printk("Unable to get major %d for sony CDU-535 cd\n",MAJOR_NR);
+		return( mem_start );
+	    }
+            blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
+            read_ahead[MAJOR_NR] = 8;               /* 8 sector (4kB) read-ahead */
+
+            sony_toc = (struct s535_sony_toc *) mem_start;
+            mem_start += sizeof(*sony_toc);
+            last_sony_subcode = (struct s535_sony_subcode *) mem_start;
+            mem_start += sizeof(*last_sony_subcode);
+            sony_buffer = (unsigned char *) mem_start;
+            mem_start += sony_buffer_size;
+
+            initialized = 1;
+         }
+      }
+   }
+
+   if ( !initialized )
+      printk( "Did not find a Sony CDU-535 drive\n");
+
+   return mem_start;
+}
+
+#endif  /* CONFIG_CDU535 */
diff -ru --new-file linux-1.0/fs/buffer.c linux/fs/buffer.c
--- linux-1.0/fs/buffer.c	Thu Mar 10 12:20:55 1994
+++ linux/fs/buffer.c	Tue Mar 15 11:37:54 1994
@@ -45,6 +45,9 @@
 #ifdef CONFIG_MCD
 extern int check_mcd_media_change(int, int);
 #endif
+#ifdef CONFIG_CDU535
+extern int sony535_check_cdrom_media_change(int, int);
+#endif
 
 static int grow_buffers(int pri, int size);
 
@@ -239,6 +242,12 @@
 #if defined(CONFIG_BLK_DEV_SR) && defined(CONFIG_SCSI)
 	 case SCSI_CDROM_MAJOR:
 		i = check_cdrom_media_change(dev, 0);
+		break;
+#endif
+
+#if defined (CONFIG_CDU535)
+         case CDU535_CDROM_MAJOR: /* Sony CDU-535 I/F CDROM */
+		i = sony535_check_cdrom_media_change(dev, 0);
 		break;
 #endif
 
diff -ru --new-file linux-1.0/fs/isofs/inode.c linux/fs/isofs/inode.c
--- linux-1.0/fs/isofs/inode.c	Sun Mar 13 18:39:14 1994
+++ linux/fs/isofs/inode.c	Tue Mar 15 11:37:55 1994
@@ -38,6 +38,9 @@
 static int check_malloc = 0;
 static int check_bread = 0;
 #endif
+#if defined(CONFIG_CDU535)
+extern int sony535_check_cdrom_media_change(int, int);
+#endif
 
 void isofs_put_super(struct super_block *sb)
 {
@@ -288,6 +291,13 @@
 	if (MAJOR(s->s_dev) == MITSUMI_CDROM_MAJOR) {
 		/* Check this one more time. */
 		if(check_mcd_media_change(s->s_dev, 0))
+		  goto out;
+	};
+#endif
+#if defined (CONFIG_CDU535)
+	if(MAJOR(s->s_dev) == CDU535_CDROM_MAJOR) {
+		/* Check this one more time. */
+		if(sony535_check_cdrom_media_change(s->s_dev, 0))
 		  goto out;
 	}
 #endif
diff -ru --new-file linux-1.0/include/linux/sonycd535.h linux/include/linux/sonycd535.h
--- linux-1.0/include/linux/sonycd535.h	Thu Jan  1 00:00:00 1970
+++ linux/include/linux/sonycd535.h	Tue Mar 15 11:37:56 1994
@@ -0,0 +1,183 @@
+#ifndef SONYCD535_H
+#define SONYCD535_H
+
+/*
+ * define all the commands recognized by the CDU-531/5
+ */
+#define SONY535_REQUEST_DRIVE_STATUS_1		(0x80)
+#define SONY535_REQUEST_SENSE			(0x82)
+#define SONY535_REQUEST_DRIVE_STATUS_2		(0x84)
+#define SONY535_REQUEST_ERROR_STATUS		(0x86)
+#define SONY535_REQUEST_AUDIO_STATUS		(0x88)
+#define SONY535_INQUIRY				(0x8a)
+
+#define SONY535_SET_INACTIVITY_TIME		(0x90)
+
+#define SONY535_SEEK_AND_READ_N_BLOCKS_1	(0xa0)
+#define SONY535_SEEK_AND_READ_N_BLOCKS_2	(0xa4)
+#define SONY535_PLAY_AUDIO			(0xa6)
+
+#define SONY535_REQUEST_DISC_CAPACITY		(0xb0)
+#define SONY535_REQUEST_TOC_DATA		(0xb2)
+#define SONY535_REQUEST_SUB_Q_DATA		(0xb4)
+#define SONY535_REQUEST_ISRC			(0xb6)
+#define SONY535_REQUEST_UPC_EAN			(0xb8)
+
+#define SONY535_SET_DRIVE_MODE			(0xc0)
+#define SONY535_REQUEST_DRIVE_MODE		(0xc2)
+#define SONY535_SET_RETRY_COUNT			(0xc4)
+
+#define SONY535_DIAGNOSTIC_1			(0xc6)
+#define SONY535_DIAGNOSTIC_4			(0xcc)
+#define SONY535_DIAGNOSTIC_5			(0xce)
+
+#define SONY535_EJECT_CADDY			(0xd0)
+#define SONY535_DISABLE_EJECT_BUTTON		(0xd2)
+#define SONY535_ENABLE_EJECT_BUTTON		(0xd4)
+
+#define SONY535_HOLD				(0xe0)
+#define SONY535_AUDIO_PAUSE_ON_OFF		(0xe2)
+#define SONY535_SET_VOLUME			(0xe8)
+
+#define SONY535_STOP				(0xf0)
+#define SONY535_SPIN_UP				(0xf2)
+#define SONY535_SPIN_DOWN			(0xf4)
+
+#define SONY535_CLEAR_PARAMETERS		(0xf6)
+#define SONY535_CLEAR_ENDING_ADDRESS		(0xf8)
+
+/*
+ * define some masks
+ */
+#define SONY535_DATA_NOT_READY_BIT		(0x1)
+#define SONY535_RESULT_NOT_READY_BIT		(0x2)
+
+/*
+ *  drive status 1
+ */
+#define SONY535_STATUS1_COMMAND_ERROR		(0x1)
+#define SONY535_STATUS1_DATA_ERROR		(0x2)
+#define SONY535_STATUS1_SEEK_ERROR		(0x4)
+#define SONY535_STATUS1_DISC_TYPE_ERROR		(0x8)
+#define SONY535_STATUS1_NOT_SPINNING		(0x10)
+#define SONY535_STATUS1_EJECT_BUTTON_PRESSED	(0x20)
+#define SONY535_STATUS1_CADDY_NOT_INSERTED	(0x40)
+#define SONY535_STATUS1_BYTE_TWO_FOLLOWS	(0x80)
+
+/*
+ * drive status 2
+ */
+#define SONY535_CDD_LOADING_ERROR		(0x7)
+#define SONY535_CDD_NO_DISC			(0x8)
+#define SONY535_CDD_UNLOADING_ERROR		(0x9)
+#define SONY535_CDD_CADDY_NOT_INSERTED		(0xd)
+#define SONY535_ATN_RESET_OCCURRED		(0x2)
+#define SONY535_ATN_DISC_CHANGED		(0x4)
+#define SONY535_ATN_RESET_AND_DISC_CHANGED	(0x6)
+#define SONY535_ATN_EJECT_IN_PROGRESS		(0xe)
+#define SONY535_ATN_BUSY			(0xf)
+
+/*
+ * define some parameters
+ */
+#define SONY535_AUDIO_DRIVE_MODE		(0)
+#define SONY535_CDROM_DRIVE_MODE		(0xe0)
+
+#define SONY535_PLAY_OP_PLAYBACK		(0)
+#define SONY535_PLAY_OP_ENTER_HOLD		(1)
+#define SONY535_PLAY_OP_SET_AUDIO_ENDING_ADDR	(2)
+#define SONY535_PLAY_OP_SCAN_FORWARD		(3)
+#define SONY535_PLAY_OP_SCAN_BACKWARD		(4)
+
+/*
+ *  convert from msf format to block number 
+ */
+#define SONY_BLOCK_NUMBER(m,s,f) (((m)*60L+(s))*75L+(f))
+#define SONY_BLOCK_NUMBER_MSF(x) (((x)[0]*60L+(x)[1])*75L+(x)[2])
+
+/*
+ *  error return values from the doSonyCmd() routines
+ */
+#define TIME_OUT			(-1)
+#define NO_CDROM			(-2)
+#define BAD_STATUS			(-3)
+#define CD_BUSY				(-4)
+#define NOT_DATA_CD			(-5)
+#define NO_ROOM				(-6)
+
+#define LOG_START_OFFSET        150     /* Offset of first logical sector */
+
+#define SONY_JIFFIES_TIMEOUT            500  /* Maximum number of jiffies (10ms)
+                                                  the drive will wait/try for an
+                                                  operation */
+#define SONY_READY_RETRIES      (50000)  /* How many times to retry a
+                                                  spin waiting for a register
+                                                  to come ready */
+#define SONY535_FAST_POLLS	(10000)   /* how many times recheck 
+                                                  status waiting for a data
+                                                  to become ready */
+
+typedef unsigned char Byte;
+
+/*
+ * This is the complete status returned from the drive configuration request
+ * command.
+ */
+struct s535_sony_drive_config
+{
+   char vendor_id[8];
+   char product_id[16];
+   char product_rev_level[4];
+};
+
+/* The following is returned from the request sub-q data command */
+struct s535_sony_subcode
+{
+   unsigned char address        :4;
+   unsigned char control        :4;
+   unsigned char track_num;
+   unsigned char index_num;
+   unsigned char rel_msf[3];
+   unsigned char abs_msf[3];
+};
+
+struct s535_sony_disc_capacity
+{
+   Byte mFirstTrack, sFirstTrack, fFirstTrack;
+   Byte mLeadOut, sLeadOut, fLeadOut;
+};
+
+/*
+ * The following is returned from the request TOC (Table Of Contents) command.
+ * (last_track_num-first_track_num+1) values are valid in tracks.
+ */
+struct s535_sony_toc
+{
+   unsigned char reserved0      :4;
+   unsigned char control0       :4;
+   unsigned char point0;
+   unsigned char first_track_num;
+   unsigned char reserved0a;
+   unsigned char reserved0b;
+   unsigned char reserved1      :4;
+   unsigned char control1       :4;
+   unsigned char point1;
+   unsigned char last_track_num;
+   unsigned char dummy1;
+   unsigned char dummy2;
+   unsigned char reserved2      :4;
+   unsigned char control2       :4;
+   unsigned char point2;
+   unsigned char lead_out_start_msf[3];
+   struct
+   {
+      unsigned char reserved    :4;
+      unsigned char control     :4;
+      unsigned char track;
+      unsigned char track_start_msf[3];
+   } tracks[100];
+
+   unsigned int lead_out_start_lba;
+};
+
+#endif /* SONYCD535_H */
