cm206.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

    cd->adapter_last = -1;	/* invalidate adapter memory */
    cd->sector_last = -1;
  }
  ++cd->openfiles;
  stats(open);
  return 0;
}

static void cm206_release(struct cdrom_device_info * cdi)
{
  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(request_queue_t * q)
{
  long int i, cd_sec_no;
  int quarter, error; 
  uch * source, * dest;
  
  while(1) {	 /* repeat until all requests have been satisfied */
    INIT_REQUEST;
    if (QUEUE_EMPTY || CURRENT->rq_status == RQ_INACTIVE)
      return;
    if (CURRENT->cmd != READ) {
      debug(("Non-read command %d on cdrom\n", CURRENT->cmd));
      end_request(0);
      continue;
    }
    spin_unlock_irq(&io_request_lock);
    error=0;
    for (i=0; i<CURRENT->nr_sectors; i++) {
      int e1, e2;
      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 (!(e1=try_adapter(cd_sec_no)) || 
	       !(e2=read_sector(cd_sec_no))) {
	source =  ((uch *) cd->sector)+16+quarter*LINUX_BLOCK_SIZE;
	memcpy(dest, source, LINUX_BLOCK_SIZE); 
      }
      else {
	error=1;
	debug(("cm206_request: %d %d\n", e1, e2));
      }
    }
    spin_lock_irq(&io_request_lock);
    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.  Note that the start of the disc must be in toc[1].fsm. 
 */
int get_toc_lba(uch track)
{
  int max=74*60*75-150, min=fsm2lba(cd->toc[1].fsm);
  int i, lba, l, old_lba=0;
  uch * q = cd->q;
  uch ct;			/* current track */
  int binary=0;
  const int skip = 3*60*75;		/* 3 minutes */

  for (i=track; i>0; i--) if (cd->toc[i].track) {
    min = fsm2lba(cd->toc[i].fsm);
    break;
  }
  lba = min + skip;
  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) { 
    int i;
    hp->cdth_trk0 = FIRST_TRACK;
    hp->cdth_trk1 = LAST_TRACK; 
				/* 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(struct cdrom_device_info * cdi, 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(struct cdrom_device_info * cdi, 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;
  }
}