scsi.c

基于组件方式开发操作系统的OSKIT源代码

       (scsi_result[3] & 0x0f) == 1))
    SDpnt->scsi_level++;

  /*
   * Accommodate drivers that want to sleep when they should be in a polling
   * loop.
   */
  SDpnt->disconnect = 0;

  /*
   * Get any flags for this device.
   */
  bflags = get_device_flags (scsi_result);

  /*
   * Set the tagged_queue flag for SCSI-II devices that purport to support
   * tagged queuing in the INQUIRY data.
   */
  SDpnt->tagged_queue = 0;
  if ((SDpnt->scsi_level >= SCSI_2) &&
      (scsi_result[7] & 2) &&
      !(bflags & BLIST_NOTQ)) {
    SDpnt->tagged_supported = 1;
    SDpnt->current_tag = 0;
  }

  /*
   * Some revisions of the Texel CD ROM drives have handshaking problems when
   * used with the Seagate controllers.  Before we know what type of device
   * we're talking to, we assume it's borken and then change it here if it
   * turns out that it isn't a TEXEL drive.
   */
  if ((bflags & BLIST_BORKEN) == 0)
    SDpnt->borken = 0;

  /*
   * If we want to only allow I/O to one of the luns attached to this device
   * at a time, then we set this flag.
   */
  if (bflags & BLIST_SINGLELUN)
    SDpnt->single_lun = 1;

  /*
   * These devices need this "key" to unlock the devices so we can use it
   */
  if ((bflags & BLIST_KEY) != 0) {
    printk ("Unlocked floptical drive.\n");
    SDpnt->lockable = 0;
    scsi_cmd[0] = MODE_SENSE;
    scsi_cmd[1] = (lun << 5) & 0xe0;
    scsi_cmd[2] = 0x2e;
    scsi_cmd[3] = 0;
    scsi_cmd[4] = 0x2a;
    scsi_cmd[5] = 0;
    SCpnt->cmd_len = 0;
    {
      struct semaphore sem = MUTEX_LOCKED;
      SCpnt->request.rq_status = RQ_SCSI_BUSY;
      SCpnt->request.sem = &sem;
      spin_lock_irq(&io_request_lock);
      scsi_do_cmd (SCpnt, (void *) scsi_cmd,
                   (void *) scsi_result, 0x2a,
                   scan_scsis_done, SCSI_TIMEOUT, 3);
      spin_unlock_irq(&io_request_lock);
      down (&sem);
      SCpnt->request.sem = NULL;
    }
  }

  /*
   * Detach the command from the device. It was just a temporary to be used while
   * scanning the bus - the real ones will be allocated later.
   */
  SDpnt->device_queue = NULL;

  /*
   * This device was already hooked up to the host in question,
   * so at this point we just let go of it and it should be fine.  We do need to
   * allocate a new one and attach it to the host so that we can further scan the bus.
   */
  SDpnt = (Scsi_Device *) scsi_init_malloc (sizeof (Scsi_Device), GFP_ATOMIC);
  *SDpnt2=SDpnt;
  if (!SDpnt)
  {
      printk ("scsi: scan_scsis_single: Cannot malloc\n");
      return 0;
  }

  /*
   * And hook up our command block to the new device we will be testing
   * for.
   */
  SDpnt->device_queue = SCpnt;
  SDpnt->online = TRUE;

  /*
   * Since we just found one device, there had damn well better be one in the list
   * already.
   */
  if( shpnt->host_queue == NULL )
      panic("scan_scsis_single: Host queue == NULL\n");

  SDtail = shpnt->host_queue;
  while (SDtail->next)
  {
      SDtail = SDtail->next;
  }

  /* Add this device to the linked list at the end */
  SDtail->next = SDpnt;
  SDpnt->prev = SDtail;
  SDpnt->next = NULL;

  /*
   * Some scsi devices cannot be polled for lun != 0 due to firmware bugs
   */
  if (bflags & BLIST_NOLUN)
    return 0;                   /* break; */

  /*
   * If this device is known to support sparse multiple units, override the
   * other settings, and scan all of them.
   */
  if (bflags & BLIST_SPARSELUN) {
    *max_dev_lun = 8;
    *sparse_lun = 1;
    return 1;
  }

  /*
   * If this device is known to support multiple units, override the other
   * settings, and scan all of them.
   */
  if (bflags & BLIST_FORCELUN) {
    *max_dev_lun = 8;
    return 1;
  }

  /*
   * REGAL CDC-4X: avoid hang after LUN 4
   */
  if (bflags & BLIST_MAX5LUN) {
    *max_dev_lun = 5;
    return 1;
  }

  /*
   * We assume the device can't handle lun!=0 if: - it reports scsi-0 (ANSI
   * SCSI Revision 0) (old drives like MAXTOR XT-3280) or - it reports scsi-1
   * (ANSI SCSI Revision 1) and Response Data Format 0
   */
  if (((scsi_result[2] & 0x07) == 0)
      ||
      ((scsi_result[2] & 0x07) == 1 &&
       (scsi_result[3] & 0x0f) == 0))
    return 0;
  return 1;
}

/*
 *  Flag bits for the internal_timeout array
 */
#define NORMAL_TIMEOUT 0
#define IN_ABORT  1
#define IN_RESET  2
#define IN_RESET2 4
#define IN_RESET3 8


/* This function takes a quick look at a request, and decides if it
 * can be queued now, or if there would be a stall while waiting for
 * something else to finish.  This routine assumes that interrupts are
 * turned off when entering the routine.  It is the responsibility
 * of the calling code to ensure that this is the case.
 */

Scsi_Cmnd * scsi_request_queueable (struct request * req, Scsi_Device * device)
{
    Scsi_Cmnd * SCpnt = NULL;
    int tablesize;
    Scsi_Cmnd * found = NULL;
    struct buffer_head * bh, *bhp;

    if (!device)
	panic ("No device passed to scsi_request_queueable().\n");

    if (req && req->rq_status == RQ_INACTIVE)
	panic("Inactive in scsi_request_queueable");

    /*
     * Look for a free command block.  If we have been instructed not to queue
     * multiple commands to multi-lun devices, then check to see what else is
     * going for this device first.
     */

    if (!device->single_lun) {
	SCpnt = device->device_queue;
	while(SCpnt){
	    if(SCpnt->request.rq_status == RQ_INACTIVE) break;
	    SCpnt = SCpnt->next;
	}
    } else {
	SCpnt = device->device_queue;
	while(SCpnt){
	    if(SCpnt->channel == device->channel
                && SCpnt->target == device->id) {
		if (SCpnt->lun == device->lun) {
		    if(found == NULL
		       && SCpnt->request.rq_status == RQ_INACTIVE)
		    {
			found=SCpnt;
		    }
		}
		if(SCpnt->request.rq_status != RQ_INACTIVE) {
		    /*
		     * I think that we should really limit things to one
		     * outstanding command per device - this is what tends
                     * to trip up buggy firmware.
		     */
		    return NULL;
		}
	    }
	    SCpnt = SCpnt->next;
	}
	SCpnt = found;
    }

    if (!SCpnt) return NULL;

    if (SCSI_BLOCK(device, device->host)) return NULL;

    if (req) {
	memcpy(&SCpnt->request, req, sizeof(struct request));
	tablesize = device->host->sg_tablesize;
	bhp = bh = req->bh;
	if(!tablesize) bh = NULL;
	/* Take a quick look through the table to see how big it is.
	 * We already have our copy of req, so we can mess with that
	 * if we want to.
	 */
	while(req->nr_sectors && bh){
	    bhp = bhp->b_reqnext;
	    if(!bhp || !CONTIGUOUS_BUFFERS(bh,bhp)) tablesize--;
	    req->nr_sectors -= bh->b_size >> 9;
	    req->sector += bh->b_size >> 9;
	    if(!tablesize) break;
	    bh = bhp;
	}
	if(req->nr_sectors && bh && bh->b_reqnext){  /* Any leftovers? */
	    SCpnt->request.bhtail = bh;
	    req->bh = bh->b_reqnext; /* Divide request */
	    bh->b_reqnext = NULL;
	    bh = req->bh;

	    /* Now reset things so that req looks OK */
	    SCpnt->request.nr_sectors -= req->nr_sectors;
	    req->current_nr_sectors = bh->b_size >> 9;
	    req->buffer = bh->b_data;
	    SCpnt->request.sem = NULL; /* Wait until whole thing done */
	} else {
	    req->rq_status = RQ_INACTIVE;
	    wake_up(&wait_for_request);
	}
    } else {
	SCpnt->request.rq_status = RQ_SCSI_BUSY;  /* Busy, but no request */
	SCpnt->request.sem = NULL;   /* And no one is waiting for the device
				      * either */
    }

    atomic_inc(&SCpnt->host->host_active); 
    SCSI_LOG_MLQUEUE(5, printk("Activating command for device %d (%d)\n", SCpnt->target,
                               atomic_read(&SCpnt->host->host_active)));
    SCpnt->use_sg = 0;               /* Reset the scatter-gather flag */
    SCpnt->old_use_sg  = 0;
    SCpnt->transfersize = 0;
    SCpnt->underflow = 0;
    SCpnt->cmd_len = 0;

/* Since not everyone seems to set the device info correctly
 * before Scsi_Cmnd gets send out to scsi_do_command, we do it here.
 */
    SCpnt->channel = device->channel;
    SCpnt->lun = device->lun;
    SCpnt->target = device->id;
    SCpnt->state = SCSI_STATE_INITIALIZING;
    SCpnt->owner = SCSI_OWNER_HIGHLEVEL;

    return SCpnt;
}

/* This function returns a structure pointer that will be valid for
 * the device.  The wait parameter tells us whether we should wait for
 * the unit to become free or not.  We are also able to tell this routine
 * not to return a descriptor if the host is unable to accept any more
 * commands for the time being.  We need to keep in mind that there is no
 * guarantee that the host remain not busy.  Keep in mind the
 * scsi_request_queueable function also knows the internal allocation scheme
 * of the packets for each device
 */

Scsi_Cmnd * scsi_allocate_device (struct request ** reqp, Scsi_Device * device,
			     int wait)
{
    kdev_t dev;
    struct request * req = NULL;
    int tablesize;
    struct buffer_head * bh, *bhp;
    struct Scsi_Host * host;
    Scsi_Cmnd * SCpnt = NULL;
    Scsi_Cmnd * SCwait = NULL;
    Scsi_Cmnd * found = NULL;

    if (!device)
	panic ("No device passed to scsi_allocate_device().\n");

    if (reqp) req = *reqp;

    /* See if this request has already been queued by an interrupt routine */
    if (req) {
	if(req->rq_status == RQ_INACTIVE) return NULL;
	dev = req->rq_dev;
    } else
        dev = 0;		/* unused */

    host = device->host;

    if (in_interrupt() && SCSI_BLOCK(device, host)) return NULL;

    while (1==1){
	if (!device->single_lun) {
	    SCpnt = device->device_queue;
	    while(SCpnt){
		SCwait = SCpnt;
		if(SCpnt->request.rq_status == RQ_INACTIVE) break;
		SCpnt = SCpnt->next;
	    }
	} else {
	    SCpnt = device->device_queue;
	    while(SCpnt){
		if(SCpnt->channel == device->channel
                   && SCpnt->target == device->id) {
		    if (SCpnt->lun == device->lun) {
			SCwait = SCpnt;
			if(found == NULL
			   && SCpnt->request.rq_status == RQ_INACTIVE)
			{
			    found=SCpnt;
			}
		    }
		    if(SCpnt->request.rq_status != RQ_INACTIVE) {
			/*
			 * I think that we should really limit things to one
			 * outstanding command per device - this is what tends
                         * to trip up buggy firmware.
			 */
			found = NULL;
			break;
		    }
		}
		SCpnt = SCpnt->next;
	    }
	    SCpnt = found;
	}

	/* See if this request has already been queued by an interrupt routine
	 */
	if (req && (req->rq_status == RQ_INACTIVE || req->rq_dev != dev)) {
	    return NULL;
	}
	if (!SCpnt || SCpnt->request.rq_status != RQ_INACTIVE)	/* Might have changed */
	{
		if (wait && SCwait && SCwait->request.rq_status != RQ_INACTIVE){
			spin_unlock(&io_request_lock);		/* FIXME!!!! */
 			sleep_on(&device->device_wait);
 			spin_lock_irq(&io_request_lock);	/* FIXME!!!! */
	 	} else {
	 		if (!wait) return NULL;
 			if (!SCwait) {
	 			printk("Attempt to allocate device channel %d,"
                                       " target %d, lun %d\n", device->channel,
                                       device->id, device->lun);
 				panic("No device found in scsi_allocate_device\n");
	 		}
 		}
	} else {
	    if (req) {
		memcpy(&SCpnt->request, req, sizeof(struct request));
		tablesize = device->host->sg_tablesize;
		bhp = bh = req->bh;
		if(!tablesize) bh = NULL;
		/* Take a quick look through the table to see how big it is.
		 * We already have our copy of req, so we can mess with that
		 * if we want to.
		 */
		while(req->nr_sectors && bh){
		    bhp = bhp->b_reqnext;
		    if(!bhp || !CONTIGUOUS_BUFFERS(bh,bhp)) tablesize--;
		    req->nr_sectors -= bh->b_size >> 9;
		    req->sector += bh->b_size >> 9;
		    if(!tablesize) break;
		    bh = bhp;
		}
		if(req->nr_sectors && bh && bh->b_reqnext){/* Any leftovers? */
		    SCpnt->request.bhtail = bh;
		    req->bh = bh->b_reqnext; /* Divide request */
		    bh->b_reqnext = NULL;
		    bh = req->bh;
		    /* Now reset things so that req looks OK */
		    SCpnt->request.nr_sectors -= req->nr_sectors;
		    req->current_nr_sectors = bh->b_size >> 9;
		    req->buffer = bh->b_data;
		    SCpnt->request.sem = NULL; /* Wait until whole thing done*/
		}
		else
		{
		    req->rq_status = RQ_INACTIVE;