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/* cm206.c. A linux-driver for the cm206 cdrom player with cm260 adapter card.
   Copyright (c) 1995, 1996 David van Leeuwen.
 
     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.
 
History:
 Started 25 jan 1994. Waiting for documentation...
 22 feb 1995: 0.1a first reasonably safe polling driver.
	      Two major bugs, one in read_sector and one in 
	      do_cm206_request, happened to cancel!
 25 feb 1995: 0.2a first reasonable interrupt driven version of above.
              uart writes are still done in polling mode. 
 25 feb 1995: 0.21a writes also in interrupt mode, still some
	      small bugs to be found... Larger buffer. 
  2 mrt 1995: 0.22 Bug found (cd-> nowhere, interrupt was called in
              initialization), read_ahead of 16. Timeouts implemented.
	      unclear if they do something...
  7 mrt 1995: 0.23 Start of background read-ahead.
 18 mrt 1995: 0.24 Working background read-ahead. (still problems)
 26 mrt 1995: 0.25 Multi-session ioctl added (kernel v1.2).
              Statistics implemented, though separate stats206.h.
	      Accessible trough ioctl 0x1000 (just a number).
	      Hard to choose between v1.2 development and 1.1.75.
	      Bottom-half doesn't work with 1.2...
	      0.25a: fixed... typo. Still problems...
  1 apr 1995: 0.26 Module support added. Most bugs found. Use kernel 1.2.n.
  5 apr 1995: 0.27 Auto-probe for the adapter card base address.
              Auto-probe for the adaptor card irq line.
  7 apr 1995: 0.28 Added lilo setup support for base address and irq.
              Use major number 32 (not in this source), officially
	      assigned to this driver.
  9 apr 1995: 0.29 Added very limited audio support. Toc_header, stop, pause,
              resume, eject. Play_track ignores track info, because we can't 
	      read a table-of-contents entry. Toc_entry is implemented
	      as a `placebo' function: always returns start of disc. 
  3 may 1995: 0.30 Audio support completed. The get_toc_entry function
              is implemented as a binary search. 
 15 may 1995: 0.31 More work on audio stuff. Workman is not easy to 
              satisfy; changed binary search into linear search.
	      Auto-probe for base address somewhat relaxed.
  1 jun 1995: 0.32 Removed probe_irq_on/off for module version.
 10 jun 1995: 0.33 Workman still behaves funny, but you should be
              able to eject and substitute another disc.
 
 An adaptation of 0.33 is included in linux-1.3.7 by Eberhard Moenkeberg
 
 18 jul 1995: 0.34 Patch by Heiko Eissfeldt included, mainly considering 
              verify_area's in the ioctls. Some bugs introduced by 
	      EM considering the base port and irq fixed. 
 
 18 dec 1995: 0.35 Add some code for error checking... no luck...
 
 We jump to reach our goal: version 1.0 in the next stable linux kernel.
 
 19 mar 1996: 0.95 Different implementation of CDROM_GET_UPC, on
	      request of Thomas Quinot. 
 25 mar 1996: 0.96 Interpretation of opening with O_WRONLY or O_RDWR:
	      open only for ioctl operation, e.g., for operation of
	      tray etc.
 4 apr 1996:  0.97 First implementation of layer between VFS and cdrom
              driver, a generic interface. Much of the functionality
	      of cm206_open() and cm206_ioctl() is transferred to a
	      new file cdrom.c and its header ucdrom.h. 
 
	      Upgrade to Linux kernel 1.3.78. 
 
 11 apr 1996  0.98 Upgrade to Linux kernel 1.3.85
              Made it more uniform.
 * 
 * Parts of the code are based upon lmscd.c written by Kai Petzke,
 * sbpcd.c written by Eberhard Moenkeberg, and mcd.c by Martin
 * Harriss, but any off-the-shelf dynamic programming algorithm won't
 * be able to find them.
 *
 * The cm206 drive interface and the cm260 adapter card seem to be 
 * sufficiently different from their cm205/cm250 counterparts
 * in order to write a complete new driver.
 * 
 * I call all routines connected to the Linux kernel something
 * with `cm206' in it, as this stuff is too series-dependent. 
 * 
 * Currently, my limited knowledge is based on:
 * - The Linux Kernel Hacker's guide, v. 0.5, by Michael K. Johnson
 * - Linux Kernel Programmierung, by Michael Beck and others
 * - Philips/LMS cm206 and cm226 product specification
 * - Philips/LMS cm260 product specification
 *
 *                       David van Leeuwen, david@tm.tno.nl.  */
#define VERSION "$Id: cm206.c,v 1.1 2005-12-20 10:16:38 jcastillo Exp $"
 
#include <linux/module.h>	
 
#include <linux/errno.h>	/* These include what we really need */
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/cdrom.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/malloc.h>
 
#include <linux/ucdrom.h>
 
#include <asm/io.h>
 
#define MAJOR_NR CM206_CDROM_MAJOR
#include <linux/blk.h>
 
#undef DEBUG
#define STATISTICS		/* record times and frequencies of events */
#undef AUTO_PROBE_MODULE
#define USE_INSW
 
#include <linux/cm206.h>
 
/* This variable defines whether or not to probe for adapter base port 
   address and interrupt request. It can be overridden by the boot 
   parameter `auto'.
*/
static int auto_probe=1;	/* Yes, why not? */
 
static int cm206_base = CM206_BASE;
static int cm206_irq = CM206_IRQ; 
 
#define POLLOOP 10000
#define READ_AHEAD 1		/* defines private buffer, waste! */
#define BACK_AHEAD 1		/* defines adapter-read ahead */
#define DATA_TIMEOUT (3*HZ)	/* measured in jiffies (10 ms) */
#define UART_TIMEOUT (5*HZ/100)
#define DSB_TIMEOUT (7*HZ)	/* time for the slowest command to finish */
 
#define LINUX_BLOCK_SIZE 512	/* WHERE is this defined? */
#define RAW_SECTOR_SIZE 2352	/* ok, is also defined in cdrom.h */
#define ISO_SECTOR_SIZE 2048
#define BLOCKS_ISO (ISO_SECTOR_SIZE/LINUX_BLOCK_SIZE) /* 4 */
#define CD_SYNC_HEAD 16		/* CD_SYNC + CD_HEAD */
 
#ifdef STATISTICS		/* keep track of errors in counters */
#define stats(i) { ++cd->stats[st_ ## i]; \
		     cd->last_stat[st_ ## i] = cd->stat_counter++; \
		 }
#else
#define stats(i) (void) 0
#endif
 
#ifdef DEBUG			/* from lmscd.c */
#define debug(a) printk a
#else
#define debug(a) (void) 0
#endif
 
typedef unsigned char uch;	/* 8-bits */
typedef unsigned short ush;	/* 16-bits */
 
struct toc_struct{		/* private copy of Table of Contents */
  uch track, fsm[3], q0;
};
 
struct cm206_struct {
  ush intr_ds;	 /* data status read on last interrupt */
  ush intr_ls;	 /* uart line status read on last interrupt*/
  uch intr_ur;			/* uart receive buffer */
  uch dsb, cc;	 /* drive status byte and condition (error) code */
  uch fool;
  int command;			/* command to be written to the uart */
  int openfiles;
  ush sector[READ_AHEAD*RAW_SECTOR_SIZE/2]; /* buffered cd-sector */
  int sector_first, sector_last;	/* range of these sector */
  struct wait_queue * uart;	/* wait for interrupt */
  struct wait_queue * data;
  struct timer_list timer;	/* time-out */
  char timed_out;
  signed char max_sectors;
  char wait_back;		/* we're waiting for a background-read */
  char background;		/* is a read going on in the background? */
  int adapter_first;		/* if so, that's the starting sector */
  int adapter_last;
  char fifo_overflowed;
  uch disc_status[7];		/* result of get_disc_status command */
#ifdef STATISTICS
  int stats[NR_STATS];
  int last_stat[NR_STATS];	/* `time' at which stat was stat */
  int stat_counter;
#endif  
  struct toc_struct toc[101];	/* The whole table of contents + lead-out */
  uch q[10];			/* Last read q-channel info */
  uch audio_status[5];		/* last read position on pause */
  uch media_changed;		/* record if media changed */
};
 
#define DISC_STATUS cd->disc_status[0]
#define FIRST_TRACK cd->disc_status[1]
#define LAST_TRACK cd->disc_status[2]
#define PAUSED cd->audio_status[0] /* misuse this memory byte! */
#define PLAY_TO cd->toc[0]	/* toc[0] records end-time in play */
 
static struct cm206_struct * cd; /* the main memory structure */
 
/* First, we define some polling functions. These are actually
   only being used in the initialization. */
 
void send_command_polled(int command)
{
  int loop=POLLOOP;
  while (!(inw(r_line_status) & ls_transmitter_buffer_empty) && loop>0) 
    --loop;
  outw(command, r_uart_transmit);
}
 
uch receive_echo_polled(void)
{
  int loop=POLLOOP;
  while (!(inw(r_line_status) & ls_receive_buffer_full) && loop>0) --loop;
  return ((uch) inw(r_uart_receive));
}
 
uch send_receive_polled(int command)
{
  send_command_polled(command);
  return receive_echo_polled();
}
 
/* The interrupt handler. When the cm260 generates an interrupt, very
   much care has to be taken in reading out the registers in the right
   order; in case of a receive_buffer_full interrupt, first the
   uart_receive must be read, and then the line status again to
   de-assert the interrupt line. It took me a couple of hours to find
   this out:-( 
 
   The function reset_cm206 appears to cause an interrupt, because
   pulling up the INIT line clears both the uart-write-buffer /and/
   the uart-write-buffer-empty mask. We call this a `lost interrupt,'
   as there seems so reason for this to happen.
*/
 
static void cm206_interrupt(int sig, void *dev_id, struct pt_regs * regs) 
/* you rang? */
{
  volatile ush fool;
  cd->intr_ds = inw(r_data_status); /* resets data_ready, data_error,
				       crc_error, sync_error, toc_ready 
				       interrupts */
  cd->intr_ls = inw(r_line_status); /* resets overrun bit */
  if (cd->intr_ls & ls_attention) stats(attention);
  /* receive buffer full? */
  if (cd->intr_ls & ls_receive_buffer_full) {	
    cd->intr_ur = inb(r_uart_receive); /* get order right! */
    cd->intr_ls = inw(r_line_status); /* resets rbf interrupt */
    if (!cd->background && cd->uart) wake_up_interruptible(&cd->uart);
  }
  /* data ready in fifo? */
  else if (cd->intr_ds & ds_data_ready) { 
    if (cd->background) ++cd->adapter_last;
    if ((cd->wait_back || !cd->background) && cd->data) 
      wake_up_interruptible(&cd->data);
    stats(data_ready);
  }
  /* ready to issue a write command? */
  else if (cd->command && cd->intr_ls & ls_transmitter_buffer_empty) {
    outw(dc_normal | (inw(r_data_status) & 0x7f), r_data_control);
    outw(cd->command, r_uart_transmit);
    cd->command=0;
    if (!cd->background) wake_up_interruptible(&cd->uart);
  }
  /* now treat errors (at least, identify them for debugging) */
  else if (cd->intr_ds & ds_fifo_overflow) {
    debug(("Fifo overflow at sectors 0x%x\n", cd->sector_first));
    fool = inw(r_fifo_output_buffer);	/* de-assert the interrupt */
    cd->fifo_overflowed=1;	/* signal one word less should be read */
    stats(fifo_overflow);
  }
  else if (cd->intr_ds & ds_data_error) {
    debug(("Data error at sector 0x%x\n", cd->sector_first));
    stats(data_error);
  }
  else if (cd->intr_ds & ds_crc_error) {
    debug(("CRC error at sector 0x%x\n", cd->sector_first));
    stats(crc_error);
  }
  else if (cd->intr_ds & ds_sync_error) {
    debug(("Sync at sector 0x%x\n", cd->sector_first));
    stats(sync_error);
  }
  else if (cd->intr_ds & ds_toc_ready) {
    /* do something appropriate */
  }
  /* couldn't see why this interrupt, maybe due to init */
  else {			
    outw(dc_normal | READ_AHEAD, r_data_control);
    stats(lost_intr);
  }
  if (cd->background && (cd->adapter_last-cd->adapter_first == cd->max_sectors
			 || cd->fifo_overflowed))
    mark_bh(CM206_BH);	/* issue a stop read command */
  stats(interrupt);
}
 
/* we have put the address of the wait queue in who */
void cm206_timeout(unsigned long who)
{
  cd->timed_out = 1;
  wake_up_interruptible((struct wait_queue **) who);
}
 
/* This function returns 1 if a timeout occurred, 0 if an interrupt
   happened */
int sleep_or_timeout(struct wait_queue ** wait, int timeout)
{
  cd->timer.data=(unsigned long) wait;
  cd->timer.expires = jiffies + timeout;
  add_timer(&cd->timer);
  interruptible_sleep_on(wait);
  del_timer(&cd->timer);
  if (cd->timed_out) {
    cd->timed_out = 0;
    return 1;
  }
  else return 0;
}
 
void cm206_delay(int jiffies) 
{
  struct wait_queue * wait = NULL;
  sleep_or_timeout(&wait, jiffies);
}
 
void send_command(int command)
{
  if (!(inw(r_line_status) & ls_transmitter_buffer_empty)) {
    cd->command = command;
    cli();			/* don't interrupt before sleep */
    outw(dc_mask_sync_error | dc_no_stop_on_error | 
	 (inw(r_data_status) & 0x7f), r_data_control);
    /* interrupt routine sends command */
    if (sleep_or_timeout(&cd->uart, UART_TIMEOUT)) {
      debug(("Time out on write-buffer\n"));
      stats(write_timeout);
      outw(command, r_uart_transmit);
    }
  }
  else outw(command, r_uart_transmit);
}
 
uch receive_echo(void)
{
  if (!(inw(r_line_status) & ls_receive_buffer_full) &&
      sleep_or_timeout(&cd->uart, UART_TIMEOUT)) {
    debug(("Time out on receive-buffer\n"));
    stats(receive_timeout);
    return ((uch) inw(r_uart_receive));
  }
  return cd->intr_ur;
}
 
inline uch send_receive(int command)
{
  send_command(command);
  return receive_echo();
}
 
uch wait_dsb(void)
{
  if (!(inw(r_line_status) & ls_receive_buffer_full) &&
      sleep_or_timeout(&cd->uart, DSB_TIMEOUT)) {
    debug(("Time out on Drive Status Byte\n"));
    stats(dsb_timeout);
    return ((uch) inw(r_uart_receive));
  }
  return cd->intr_ur;
}
 
int type_0_command(int command, int expect_dsb)
{
  int e;
  if (command != (e=send_receive(command))) {
    debug(("command 0x%x echoed as 0x%x\n", command, e));
    stats(echo);
    return -1;
  }
  if (expect_dsb) {
    cd->dsb = wait_dsb();	/* wait for command to finish */
  }
  return 0;
}
 
int type_1_command(int command, int bytes, uch * status) /* returns info */
{
  int i;
  if (type_0_command(command,0)) return -1;
  for(i=0; i<bytes; i++) 
    status[i] = send_receive(c_gimme);
  return 0;
}  
 
/* This function resets the adapter card. We'd better not do this too */
/* often, because it tends to generate `lost interrupts.' */
void reset_cm260(void)
{
  outw(dc_normal | dc_initialize | READ_AHEAD, r_data_control);
  udelay(10);			/* 3.3 mu sec minimum */
  outw(dc_normal | READ_AHEAD, r_data_control);
}
 
/* fsm: frame-sec-min from linear address */
void fsm(int lba, uch * fsm) 
{
  fsm[0] = lba % 75;
  lba /= 75; lba += 2;
  fsm[1] = lba % 60; fsm[2] = lba / 60;
}
 
inline int fsm2lba(uch * fsm) 
{
  return fsm[0] + 75*(fsm[1]-2 + 60*fsm[2]);
}
 
inline int f_s_m2lba(uch f, uch s, uch m)
{
  return f + 75*(s-2 + 60*m);
}
 
int start_read(int start) 
{
  uch read_sector[4] = {c_read_data, };
  int i, e;
 
  fsm(start, &read_sector[1]);
  for (i=0; i<4; i++) 
    if (read_sector[i] != (e=send_receive(read_sector[i]))) {
      debug(("read_sector: %x echoes %x\n", read_sector[i], e));
      stats(echo);
      return -1;
    }
  return 0;
}
 
int stop_read(void)
{
  type_0_command(c_stop,0);
  if(receive_echo() != 0xff) {
    debug(("c_stop didn't send 0xff\n"));
    stats(stop_0xff);
    return -1;
  }
  return 0;
}  
 
/* This function starts to read sectors in adapter memory, the
   interrupt routine should stop the read. In fact, the bottom_half
   routine takes care of this. Set a flag `background' in the cd
   struct to indicate the process. */
 
int read_background(int start, int reading)
{
  if (cd->background) return -1; /* can't do twice */
  outw(dc_normal | BACK_AHEAD, r_data_control);
  if (!reading && start_read(start)) return -2;
  cd->adapter_first = cd->adapter_last = start; 
  cd->background = 1;		/* flag a read is going on */
  return 0;
}
 
#ifdef USE_INSW
#define transport_data insw
#else
/* this routine implements insw(,,). There was a time i had the
   impression that there would be any difference in error-behaviour. */
void transport_data(int port, ush * dest, int count) 
{
  int i;
  ush * d;
  for (i=0, d=dest; i<count; i++, d++) 
    *d = inw(port);
}
#endif
 
int read_sector(int start)
{
  if (cd->background) {
    cd->background=0;
    cd->adapter_last = -1;	/* invalidate adapter memory */
    stop_read();
  }
  cd->fifo_overflowed=0;
  reset_cm260();		/* empty fifo etc. */
  if (start_read(start)) return -1;
  if (sleep_or_timeout(&cd->data, DATA_TIMEOUT)) {
    debug(("Read timed out sector 0x%x\n", start));
    stats(read_timeout);
    stop_read();
    return -3;		
  }
  transport_data(r_fifo_output_buffer, cd->sector, 
		 READ_AHEAD*RAW_SECTOR_SIZE/2);
  if (read_background(start+READ_AHEAD,1)) stats(read_background);
  cd->sector_first = start; cd->sector_last = start+READ_AHEAD;
  stats(read_restarted);
  return 0;
}
 
/* The function of bottom-half is to send a stop command to the drive
   This isn't easy because the routine is not `owned' by any process;
   we can't go to sleep! The variable cd->background gives the status:
   0 no read pending
   1 a read is pending
   2 c_stop waits for write_buffer_empty
   3 c_stop waits for receive_buffer_full: echo
   4 c_stop waits for receive_buffer_full: 0xff
*/
 
void cm206_bh(void)
{
  debug(("bh: %d\n", cd->background));
  switch (cd->background) {
  case 1:
    stats(bh);
    if (!(cd->intr_ls & ls_transmitter_buffer_empty)) {
      cd->command = c_stop;
      outw(dc_mask_sync_error | dc_no_stop_on_error | 
	   (inw(r_data_status) & 0x7f), r_data_control);
      cd->background=2;
      break;			/* we'd better not time-out here! */
    }
    else outw(c_stop, r_uart_transmit);
    /* fall into case 2: */
  case 2:			
    /* the write has been satisfied by interrupt routine */
    cd->background=3;
    break;
  case 3:
    if (cd->intr_ur != c_stop) {
      debug(("cm206_bh: c_stop echoed 0x%x\n", cd->intr_ur));
      stats(echo);
    }
    cd->background++;
    break;
  case 4:
    if (cd->intr_ur != 0xff) {
      debug(("cm206_bh: c_stop reacted with 0x%x\n", cd->intr_ur));
      stats(stop_0xff);
    }
    cd->background=0;
  }
}
 
/* This command clears the dsb_possible_media_change flag, so we must 
 * retain it.
 */
void get_drive_status(void)
{
  uch status[2];
  type_1_command(c_drive_status, 2, status); /* this might be done faster */
  cd->dsb=status[0];
  cd->cc=status[1];
  cd->media_changed |= 
    !!(cd->dsb & (dsb_possible_media_change | 
		  dsb_drive_not_ready | dsb_tray_not_closed));
}
 
void get_disc_status(void)
{
  if (type_1_command(c_disc_status, 7, cd->disc_status)) {
    debug(("get_disc_status: error\n"));
  }
}
 
/* The new open. The real opening strategy is defined in cdrom.c. */
 
static int cm206_open(kdev_t dev, int purpose) 
{
  if (!cd->openfiles) {		/* reset only first time */
    cd->background=0;
    reset_cm260();
    cd->adapter_last = -1;	/* invalidate adapter memory */
    cd->sector_last = -1;
  }
  ++cd->openfiles; MOD_INC_USE_COUNT;
  stats(open);
  return 0;
}
 
static void cm206_release(kdev_t dev)
{
  if (cd->openfiles==1) {
    if (cd->background) {
      cd->background=0;
      stop_read();
    }
    cd->sector_last = -1;	/* Make our internal buffer invalid */
    FIRST_TRACK = 0;		/* No valid disc status */
  }
  --cd->openfiles; MOD_DEC_USE_COUNT;
}
 
/* Empty buffer empties $sectors$ sectors of the adapter card buffer,
 * and then reads a sector in kernel memory.  */
void empty_buffer(int sectors) 
{
  while (sectors>=0) {
    transport_data(r_fifo_output_buffer, cd->sector + cd->fifo_overflowed, 
	 RAW_SECTOR_SIZE/2 - cd->fifo_overflowed);
    --sectors;
    ++cd->adapter_first;	/* update the current adapter sector */
    cd->fifo_overflowed=0;	/* reset overflow bit */
    stats(sector_transferred);
  } 
  cd->sector_first=cd->adapter_first-1;
  cd->sector_last=cd->adapter_first; /* update the buffer sector */
}
 
/* try_adapter. This function determines if the requested sector is
   in adapter memory, or will appear there soon. Returns 0 upon
   success */
int try_adapter(int sector)
{
  if (cd->adapter_first <= sector && sector < cd->adapter_last) { 
    /* sector is in adapter memory */
    empty_buffer(sector - cd->adapter_first);
    return 0;
  }
  else if (cd->background==1 && cd->adapter_first <= sector
	   && sector < cd->adapter_first+cd->max_sectors) {
    /* a read is going on, we can wait for it */
    cd->wait_back=1;
    while (sector >= cd->adapter_last) {
      if (sleep_or_timeout(&cd->data, DATA_TIMEOUT)) {
	debug(("Timed out during background wait: %d %d %d %d\n", sector, 
	       cd->adapter_last, cd->adapter_first, cd->background));
	stats(back_read_timeout);
	cd->wait_back=0;
	return -1;
      }
    }
    cd->wait_back=0;
    empty_buffer(sector - cd->adapter_first);
    return 0;
  }
  else return -2;
}
 
/* This is not a very smart implementation. We could optimize for 
   consecutive block numbers. I'm not convinced this would really
   bring down the processor load. */
static void do_cm206_request(void)
{
  long int i, cd_sec_no;
  int quarter, error; 
  uch * source, * dest;
 
  while(1) {	 /* repeat until all requests have been satisfied */
    INIT_REQUEST;
    if (CURRENT == NULL || CURRENT->rq_status == RQ_INACTIVE)
      return;
    if (CURRENT->cmd != READ) {
      debug(("Non-read command %d on cdrom\n", CURRENT->cmd));
      end_request(0);
      continue;
    }
    error=0;
    for (i=0; i<CURRENT->nr_sectors; i++) {
      cd_sec_no = (CURRENT->sector+i)/BLOCKS_ISO; /* 4 times 512 bytes */
      quarter = (CURRENT->sector+i) % BLOCKS_ISO; 
      dest = CURRENT->buffer + i*LINUX_BLOCK_SIZE;
      /* is already in buffer memory? */
      if (cd->sector_first <= cd_sec_no && cd_sec_no < cd->sector_last) {
	source = ((uch *) cd->sector) + 16 + quarter*LINUX_BLOCK_SIZE 
	  + (cd_sec_no-cd->sector_first)*RAW_SECTOR_SIZE;
 	memcpy(dest, source, LINUX_BLOCK_SIZE); 
      }
      else if (!try_adapter(cd_sec_no) || !read_sector(cd_sec_no)) {
	source =  ((uch *) cd->sector)+16+quarter*LINUX_BLOCK_SIZE;
	memcpy(dest, source, LINUX_BLOCK_SIZE); 
      }
      else {
	error=1;
      }
    }
    end_request(!error);
  }
}
 
/* Audio support. I've tried very hard, but the cm206 drive doesn't 
   seem to have a get_toc (table-of-contents) function, while i'm
   pretty sure it must read the toc upon disc insertion. Therefore
   this function has been implemented through a binary search 
   strategy. All track starts that happen to be found are stored in
   cd->toc[], for future use. 
 
   I've spent a whole day on a bug that only shows under Workman---
   I don't get it. Tried everything, nothing works. If workman asks
   for track# 0xaa, it'll get the wrong time back. Any other program
   receives the correct value. I'm stymied.
*/
 
/* seek seeks to address lba. It does wait to arrive there. */
void seek(int lba)
{
  int i;
  uch seek_command[4]={c_seek, };
 
  fsm(lba, &seek_command[1]);
  for (i=0; i<4; i++) type_0_command(seek_command[i], 0);
  cd->dsb = wait_dsb();
}
 
uch bcdbin(unsigned char bcd)	/* stolen from mcd.c! */
{
  return (bcd >> 4)*10 + (bcd & 0xf);
} 
 
inline uch normalize_track(uch track) 
{
  if (track<1) return 1;
  if (track>LAST_TRACK) return LAST_TRACK+1;
  return track;
}
 
/* This function does a binary search for track start. It records all
 * tracks seen in the process. Input $track$ must be between 1 and
 * #-of-tracks+1 */
int get_toc_lba(uch track)
{
  int max=74*60*75-150, min=0;
  int i, lba, l, old_lba=0;
  uch * q = cd->q;
  uch ct;			/* current track */
  int binary=0;
  const int skip = 3*60*75;
 
  for (i=track; i>0; i--) if (cd->toc[i].track) {
    min = fsm2lba(cd->toc[i].fsm);
    break;
  }
  lba = min + skip;		/* 3 minutes */
  do {
    seek(lba); 
    type_1_command(c_read_current_q, 10, q);
    ct = normalize_track(q[1]);
    if (!cd->toc[ct].track) {
      l = q[9]-bcdbin(q[5]) + 75*(q[8]-bcdbin(q[4])-2 + 
				  60*(q[7]-bcdbin(q[3])));
      cd->toc[ct].track=q[1];	/* lead out still 0xaa */
      fsm(l, cd->toc[ct].fsm);
      cd->toc[ct].q0 = q[0];	/* contains adr and ctrl info */
      if (ct==track) return l;
    }
    old_lba=lba;
    if (binary) {
      if (ct < track) min = lba; else max = lba;
      lba = (min+max)/2; 
    } else {
      if(ct < track) lba += skip;
      else {
	binary=1;
	max = lba; min = lba - skip;
	lba = (min+max)/2;
      }
    }
  } while (lba!=old_lba);
  return lba;
}
 
void update_toc_entry(uch track) 
{
  track = normalize_track(track);
  if (!cd->toc[track].track) get_toc_lba(track);
}
 
/* return 0 upon success */
int read_toc_header(struct cdrom_tochdr * hp)
{
  if (!FIRST_TRACK) get_disc_status();
  if (hp && DISC_STATUS & cds_all_audio) { /* all audio */
    int i;
    hp->cdth_trk0 = FIRST_TRACK;
    hp->cdth_trk1 = LAST_TRACK;
    cd->toc[1].track=1;		/* fill in first track position */
    for (i=0; i<3; i++) cd->toc[1].fsm[i] = cd->disc_status[3+i];
    update_toc_entry(LAST_TRACK+1);		/* find most entries */
    return 0;
  }
  return -1;
}  
 
void play_from_to_msf(struct cdrom_msf* msfp)
{
  uch play_command[] = {c_play, 
	   msfp->cdmsf_frame0, msfp->cdmsf_sec0, msfp->cdmsf_min0,
	   msfp->cdmsf_frame1, msfp->cdmsf_sec1, msfp->cdmsf_min1, 2, 2};
  int i;
  for (i=0; i<9; i++) type_0_command(play_command[i], 0);
  for (i=0; i<3; i++) 
    PLAY_TO.fsm[i] = play_command[i+4];
  PLAY_TO.track = 0;		/* say no track end */
  cd->dsb = wait_dsb();
}  
 
void play_from_to_track(int from, int to)
{
  uch play_command[8] = {c_play, };
  int i;
 
  if (from==0) {		/* continue paused play */
    for (i=0; i<3; i++) { 
      play_command[i+1] = cd->audio_status[i+2];
      play_command[i+4] = PLAY_TO.fsm[i];
    }
  } else {
    update_toc_entry(from); update_toc_entry(to+1);
    for (i=0; i<3; i++) {
      play_command[i+1] = cd->toc[from].fsm[i];
      PLAY_TO.fsm[i] = play_command[i+4] = cd->toc[to+1].fsm[i];
    }
    PLAY_TO.track = to; 
  }
  for (i=0; i<7; i++) type_0_command(play_command[i],0);
  for (i=0; i<2; i++) type_0_command(0x2, 0); /* volume */
  cd->dsb = wait_dsb();
}
 
int get_current_q(struct cdrom_subchnl * qp)
{
  int i;
  uch * q = cd->q;
  if (type_1_command(c_read_current_q, 10, q)) return 0;
/*  q[0] = bcdbin(q[0]); Don't think so! */
  for (i=2; i<6; i++) q[i]=bcdbin(q[i]); 
  qp->cdsc_adr = q[0] & 0xf; qp->cdsc_ctrl = q[0] >> 4;	/* from mcd.c */
  qp->cdsc_trk = q[1];  qp->cdsc_ind = q[2];
  if (qp->cdsc_format == CDROM_MSF) {
    qp->cdsc_reladdr.msf.minute = q[3];
    qp->cdsc_reladdr.msf.second = q[4];
    qp->cdsc_reladdr.msf.frame = q[5];
    qp->cdsc_absaddr.msf.minute = q[7];
    qp->cdsc_absaddr.msf.second = q[8];
    qp->cdsc_absaddr.msf.frame = q[9];
  } else {
    qp->cdsc_reladdr.lba = f_s_m2lba(q[5], q[4], q[3]);
    qp->cdsc_absaddr.lba = f_s_m2lba(q[9], q[8], q[7]);
  }
  get_drive_status();
  if (cd->dsb & dsb_play_in_progress) 
    qp->cdsc_audiostatus = CDROM_AUDIO_PLAY ;
  else if (PAUSED) 
    qp->cdsc_audiostatus = CDROM_AUDIO_PAUSED;
  else qp->cdsc_audiostatus = CDROM_AUDIO_NO_STATUS;
  return 0;
}
 
void invalidate_toc(void)
{
  memset(cd->toc, 0, sizeof(cd->toc));
  memset(cd->disc_status, 0, sizeof(cd->disc_status));
}
 
/* cdrom.c guarantees that cdte_format == CDROM_MSF */
void get_toc_entry(struct cdrom_tocentry * ep)
{
  uch track = normalize_track(ep->cdte_track);
  update_toc_entry(track);
  ep->cdte_addr.msf.frame = cd->toc[track].fsm[0];
  ep->cdte_addr.msf.second = cd->toc[track].fsm[1];
  ep->cdte_addr.msf.minute = cd->toc[track].fsm[2];
  ep->cdte_adr = cd->toc[track].q0 & 0xf; 
  ep->cdte_ctrl = cd->toc[track].q0 >> 4;
  ep->cdte_datamode=0;
}
 
/* Audio ioctl.  Ioctl commands connected to audio are in such an
 * idiosyncratic i/o format, that we leave these untouched. Return 0
 * upon success. Memory checking has been done by cdrom_ioctl(), the
 * calling function, as well as LBA/MSF sanitization.
*/
int cm206_audio_ioctl(kdev_t dev, unsigned int cmd, void * arg)
{
  switch (cmd) {
  case CDROMREADTOCHDR: 
    return read_toc_header((struct cdrom_tochdr *) arg);
  case CDROMREADTOCENTRY: 	
    get_toc_entry((struct cdrom_tocentry *) arg);
    return 0;
  case CDROMPLAYMSF: 
    play_from_to_msf((struct cdrom_msf *) arg);
    return 0;
  case CDROMPLAYTRKIND:		/* admittedly, not particularly beautiful */
    play_from_to_track(((struct cdrom_ti *)arg)->cdti_trk0, 
		       ((struct cdrom_ti *)arg)->cdti_trk1);
    return 0;
  case CDROMSTOP: 
    PAUSED=0;
    if (cd->dsb & dsb_play_in_progress) return type_0_command(c_stop, 1);
    else return 0;
  case CDROMPAUSE: 
    get_drive_status();
    if (cd->dsb & dsb_play_in_progress) {
      type_0_command(c_stop, 1);
      type_1_command(c_audio_status, 5, cd->audio_status);
      PAUSED=1;	/* say we're paused */
    }
    return 0;
  case CDROMRESUME:
    if (PAUSED) play_from_to_track(0,0);
    PAUSED=0;
    return 0;
  case CDROMSTART:
  case CDROMVOLCTRL:
    return 0;
  case CDROMSUBCHNL: 
    return get_current_q((struct cdrom_subchnl *)arg);
  default:
    return -EINVAL;
  }
}
 
/* Ioctl. These ioctls are specific to the cm206 driver. I have made
   some driver statistics accessible through ioctl calls.
 */
 
static int cm206_ioctl(kdev_t dev, unsigned int cmd, unsigned long arg)
{
  switch (cmd) {
#ifdef STATISTICS
  case CM206CTL_GET_STAT:
    if (arg >= NR_STATS) return -EINVAL;
    else return cd->stats[arg];
  case CM206CTL_GET_LAST_STAT:
    if (arg >= NR_STATS) return -EINVAL;
    else return cd->last_stat[arg];
#endif    
  default:
    debug(("Unknown ioctl call 0x%x\n", cmd));
    return -EINVAL;
  }
}     
 
int cm206_media_changed(kdev_t dev) 
{
  if (cd != NULL) {
    int r;
    get_drive_status();		/* ensure cd->media_changed OK */
    r = cd->media_changed;
    cd->media_changed = 0;	/* clear bit */
    return r;
  }
  else return -EIO;
}
 
/* The new generic cdrom support. Routines should be concise, most of
   the logic should be in cdrom.c */
 
/* returns number of times device is in use */
int cm206_open_files(kdev_t dev)	
{
  if (cd) return cd->openfiles;
  return -1;
}
 
/* controls tray movement */
int cm206_tray_move(kdev_t dev, int position) 
{
  if (position) {		/* 1: eject */
    type_0_command(c_open_tray,1);
    invalidate_toc();
  } 
  else type_0_command(c_close_tray, 1);	/* 0: close */
  return 0;
}
 
/* gives current state of the drive */
int cm206_drive_status(kdev_t dev)
{
  get_drive_status();
  if (cd->dsb & dsb_tray_not_closed) return CDS_TRAY_OPEN;
  if (!(cd->dsb & dsb_disc_present)) return CDS_NO_DISC; 
  if (cd->dsb & dsb_drive_not_ready) return CDS_DRIVE_NOT_READY;
  return CDS_DISC_OK;
}
 
/* gives current state of disc in drive */
int cm206_disc_status(kdev_t dev)
{
  uch xa;
  get_drive_status();
  if ((cd->dsb & dsb_not_useful) | !(cd->dsb & dsb_disc_present))
    return CDS_NO_DISC;
  get_disc_status();
  if (DISC_STATUS & cds_all_audio) return CDS_AUDIO;
  xa = DISC_STATUS >> 4;
  switch (xa) {
  case 0: return CDS_DATA_1;	/* can we detect CDS_DATA_2? */
  case 1: return CDS_XA_2_1;	/* untested */
  case 2: return CDS_XA_2_2;
  }
  return 0;
}
 
/* locks or unlocks door lock==1: lock; return 0 upon success */
int cm206_lock_door(kdev_t dev, int lock)
{
  uch command = (lock) ? c_lock_tray : c_unlock_tray;
  type_0_command(command, 1);	/* wait and get dsb */
  /* the logic calculates the success, 0 means successful */
  return lock ^ ((cd->dsb & dsb_tray_locked) != 0);
}
 
/* Although a session start should be in LBA format, we return it in 
   MSF format because it is slightly easier, and the new generic ioctl
   will take care of the necessary conversion. */
int cm206_get_last_session(kdev_t dev, struct cdrom_multisession * mssp) 
{
  if (!FIRST_TRACK) get_disc_status();
  if (mssp != NULL) {
    if (DISC_STATUS & cds_multi_session) { /* multi-session */
      mssp->addr.msf.frame = cd->disc_status[3];
      mssp->addr.msf.second = cd->disc_status[4];
      mssp->addr.msf.minute = cd->disc_status[5];
      mssp->addr_format = CDROM_MSF;
      mssp->xa_flag = 1;
    } else {
      mssp->xa_flag = 0;
    }
    return 1;
  }
  return 0;
}
 
int cm206_get_upc(kdev_t dev, struct cdrom_mcn * mcn)
{
  uch upc[10];
  char * ret = mcn->medium_catalog_number;
  int i;
 
  if (type_1_command(c_read_upc, 10, upc)) return -EIO;
  for (i=0; i<13; i++) {
    int w=i/2+1, r=i%2;
    if (r) ret[i] = 0x30 | (upc[w] & 0x0f);
    else ret[i] = 0x30 | ((upc[w] >> 4) & 0x0f);
  }
  ret[13] = '\0';
  return 0;
} 
 
int cm206_reset(kdev_t dev)
{
  stop_read();
  reset_cm260();
  outw(dc_normal | dc_break | READ_AHEAD, r_data_control);
  udelay(1000);			/* 750 musec minimum */
  outw(dc_normal | READ_AHEAD, r_data_control);
  cd->sector_last = -1;		/* flag no data buffered */
  cd->adapter_last = -1;    
  invalidate_toc();
  return 0;
}
 
static struct cdrom_device_ops cm206_dops = {
  cm206_open,			/* open */
  cm206_release,		/* release */
  cm206_open_files,		/* number of open_files */
  cm206_drive_status,		/* drive status */
  cm206_disc_status,		/* disc status */
  cm206_media_changed,		/* media changed */
  cm206_tray_move,		/* tray move */
  cm206_lock_door,		/* lock door */
  NULL,				/* select speed */
  NULL,				/* select disc */
  cm206_get_last_session,	/* get last session */
  cm206_get_upc,		/* get universal product code */
  cm206_reset,			/* hard reset */
  cm206_audio_ioctl,		/* audio ioctl */
  cm206_ioctl,			/* device-specific ioctl */
  CDC_CLOSE_TRAY | CDC_OPEN_TRAY | CDC_LOCK | CDC_MULTI_SESSION |
    CDC_MEDIA_CHANGED | CDC_MCN | CDC_PLAY_AUDIO, /* capability */
  0,				/* mask flags */
  2,				/* maximum speed */
  1,				/* number of minor devices */
  1,				/* number of discs */
  0,				/* options, ignored */
  0				/* mc_flags, ignored */
};
 
/* This routine gets called during init if thing go wrong, can be used
 * in cleanup_module as well. */
void cleanup(int level)
{
  switch (level) {
  case 4: 
    if (unregister_cdrom(MAJOR_NR, "cm206")) {
      printk("Can't unregister cdrom cm206\n");
      return;
    }
    if (unregister_blkdev(MAJOR_NR, "cm206")) {
      printk("Can't unregister major cm206\n");
      return;
    }
  case 3: 
    free_irq(cm206_irq, NULL);
  case 2: 
  case 1: 
    kfree(cd);
    release_region(cm206_base, 16);
  default:
  }
}
 
/* This function probes for the adapter card. It returns the base
   address if it has found the adapter card. One can specify a base 
   port to probe specifically, or 0 which means span all possible
   bases. 
 
   Linus says it is too dangerous to use writes for probing, so we
   stick with pure reads for a while. Hope that 8 possible ranges,
   check_region, 15 bits of one port and 6 of another make things
   likely enough to accept the region on the first hit...
 */
int probe_base_port(int base)
{
  int b=0x300, e=0x370;		/* this is the range of start addresses */
  volatile int fool, i;
 
  if (base) b=e=base;
  for (base=b; base<=e; base += 0x10) {
    if (check_region(base, 0x10)) continue;
    for (i=0; i<3; i++) 
      fool = inw(base+2); /* empty possibly uart_receive_buffer */
    if((inw(base+6) & 0xffef) != 0x0001 || /* line_status */
       (inw(base) & 0xad00) != 0) /* data status */
      continue;
    return(base);
  }
  return 0;
}
 
#if !defined(MODULE) || defined(AUTO_PROBE_MODULE)
/* Probe for irq# nr. If nr==0, probe for all possible irq's. */
int probe_irq(int nr) {
  int irqs, irq;
  outw(dc_normal | READ_AHEAD, r_data_control);	/* disable irq-generation */
  sti(); 
  irqs = probe_irq_on();
  reset_cm260();		/* causes interrupt */
  udelay(100);			/* wait for it */
  irq = probe_irq_off(irqs);
  outw(dc_normal | READ_AHEAD, r_data_control);	/* services interrupt */
  if (nr && irq!=nr && irq>0) return 0;	/* wrong interrupt happened */
  else return irq;
}
#endif
 
int cm206_init(void)
{
  uch e=0;
  long int size=sizeof(struct cm206_struct);
 
  printk(KERN_INFO VERSION);
  cm206_base = probe_base_port(auto_probe ? 0 : cm206_base);
  if (!cm206_base) {
    printk(" can't find adapter!\n");
    return -EIO;
  }
  printk(" adapter at 0x%x", cm206_base);
  request_region(cm206_base, 16, "cm206");
  cd = (struct cm206_struct *) kmalloc(size, GFP_KERNEL);
  if (!cd) return -EIO;
  /* Now we have found the adaptor card, try to reset it. As we have
   * found out earlier, this process generates an interrupt as well,
   * so we might just exploit that fact for irq probing! */
#if !defined(MODULE) || defined(AUTO_PROBE_MODULE)
  cm206_irq = probe_irq(auto_probe ? 0 : cm206_irq);	
  if (cm206_irq<=0) {
    printk("can't find IRQ!\n");
    cleanup(1);
    return -EIO;
  }
  else printk(" IRQ %d found\n", cm206_irq);
#else
  cli();
  reset_cm260();
  /* Now, the problem here is that reset_cm260 can generate an
     interrupt. It seems that this can cause a kernel oops some time
     later. So we wait a while and `service' this interrupt. */
  udelay(10);
  outw(dc_normal | READ_AHEAD, r_data_control);
  sti();
  printk(" using IRQ %d\n", cm206_irq);
#endif
  if (send_receive_polled(c_drive_configuration) != c_drive_configuration) 
    {
      printk(" drive not there\n");
      cleanup(1);
      return -EIO;
    }
  e = send_receive_polled(c_gimme);
  printk(KERN_INFO "Firmware revision %d", e & dcf_revision_code);
  if (e & dcf_transfer_rate) printk(" double");
  else printk(" single");
  printk(" speed drive");
  if (e & dcf_motorized_tray) printk(", motorized tray");
  if (request_irq(cm206_irq, cm206_interrupt, 0, "cm206", NULL)) {
    printk("\nUnable to reserve IRQ---aborted\n");
    cleanup(2);
    return -EIO;
  }
  printk(".\n");
  if (register_blkdev(MAJOR_NR, "cm206", &cdrom_fops) != 0) {
    printk("Cannot register for major %d!\n", MAJOR_NR);
    cleanup(3);
    return -EIO;
  }
  if (register_cdrom(MAJOR_NR, "cm206", &cm206_dops) != 0) {
    printk("Cannot register for cdrom %d!\n", MAJOR_NR);
    cleanup(3);
    return -EIO;
  }    
  blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
  read_ahead[MAJOR_NR] = 16;	/* reads ahead what? */
  init_bh(CM206_BH, cm206_bh);
 
  memset(cd, 0, sizeof(*cd));	/* give'm some reasonable value */
  cd->sector_last = -1;		/* flag no data buffered */
  cd->adapter_last = -1;
  cd->timer.function = cm206_timeout;
  cd->max_sectors = (inw(r_data_status) & ds_ram_size) ? 24 : 97;
  printk(KERN_INFO "%d kB adapter memory available, "  
	 " %ld bytes kernel memory used.\n", cd->max_sectors*2, size);
  return 0;
}
 
#ifdef MODULE
 
static int cm206[2] = {0,0};	/* for compatible `insmod' parameter passing */
 
void parse_options(void) 
{
  int i;
  for (i=0; i<2; i++) {
    if (0x300 <= cm206[i] && i<= 0x370 && cm206[i] % 0x10 == 0) {
      cm206_base = cm206[i];
      auto_probe=0;
    }
    else if (3 <= cm206[i] && cm206[i] <= 15) {
      cm206_irq = cm206[i];
      auto_probe=0;
    }
  }
}
 
int init_module(void)
{
	parse_options();
#if !defined(AUTO_PROBE_MODULE)
	auto_probe=0;
#endif
	return cm206_init();
}
 
void cleanup_module(void)
{
  cleanup(4);
  printk(KERN_INFO "cm206 removed\n");
}
 
#else /* !MODULE */
 
/* This setup function accepts either `auto' or numbers in the range
 * 3--11 (for irq) or 0x300--0x370 (for base port) or both. */
void cm206_setup(char *s, int *p)
{
  int i;
  if (!strcmp(s, "auto")) auto_probe=1;
  for(i=1; i<=p[0]; i++) {
    if (0x300 <= p[i] && i<= 0x370 && p[i] % 0x10 == 0) {
      cm206_base = p[i];
      auto_probe = 0;
    }
    else if (3 <= p[i] && p[i] <= 15) {
      cm206_irq = p[i];
      auto_probe = 0;
    }
  }
}
#endif /* MODULE */
/*
 * Local variables:
 * compile-command: "gcc -DMODULE -D__KERNEL__ -I/usr/src/linux/include/linux -Wall -Wstrict-prototypes -O2 -m486 -c cm206.c -o cm206.o"
 * End:
 */