ub.c

Linux块设备驱动源码

			printk(KERN_NOTICE
			     "%s: Unable to submit GetMaxLUN (%d)\n",
			     sc->name, rc);
		}
		goto err_submit;
	}

	init_timer(&timer);
	timer.function = ub_probe_timeout;
	timer.data = (unsigned long) &compl;
	timer.expires = jiffies + UB_CTRL_TIMEOUT;
	add_timer(&timer);

	wait_for_completion(&compl);

	del_timer_sync(&timer);
	usb_kill_urb(&sc->work_urb);

	if ((rc = sc->work_urb.status) < 0) {
		if (rc == -EPIPE) {
			printk("%s: Stall at GetMaxLUN, using 1 LUN\n",
			     sc->name); /* P3 */
		} else {
			printk(KERN_NOTICE
			     "%s: Error at GetMaxLUN (%d)\n",
			     sc->name, rc);
		}
		goto err_io;
	}

	if (sc->work_urb.actual_length != 1) {
		printk("%s: GetMaxLUN returned %d bytes\n", sc->name,
		    sc->work_urb.actual_length); /* P3 */
		nluns = 0;
	} else {
		if ((nluns = *p) == 55) {
			nluns = 0;
		} else {
  			/* GetMaxLUN returns the maximum LUN number */
			nluns += 1;
			if (nluns > UB_MAX_LUNS)
				nluns = UB_MAX_LUNS;
		}
		printk("%s: GetMaxLUN returned %d, using %d LUNs\n", sc->name,
		    *p, nluns); /* P3 */
	}

	kfree(p);
	return nluns;

err_io:
err_submit:
	kfree(p);
err_alloc:
	return rc;
}

/*
 * Clear initial stalls.
 */
static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
{
	int endp;
	struct usb_ctrlrequest *cr;
	struct completion compl;
	struct timer_list timer;
	int rc;

	init_completion(&compl);

	endp = usb_pipeendpoint(stalled_pipe);
	if (usb_pipein (stalled_pipe))
		endp |= USB_DIR_IN;

	cr = &sc->work_cr;
	cr->bRequestType = USB_RECIP_ENDPOINT;
	cr->bRequest = USB_REQ_CLEAR_FEATURE;
	cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
	cr->wIndex = cpu_to_le16(endp);
	cr->wLength = cpu_to_le16(0);

	usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
	    (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
	sc->work_urb.actual_length = 0;
	sc->work_urb.error_count = 0;
	sc->work_urb.status = 0;

	if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
		printk(KERN_WARNING
		     "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
		return rc;
	}

	init_timer(&timer);
	timer.function = ub_probe_timeout;
	timer.data = (unsigned long) &compl;
	timer.expires = jiffies + UB_CTRL_TIMEOUT;
	add_timer(&timer);

	wait_for_completion(&compl);

	del_timer_sync(&timer);
	usb_kill_urb(&sc->work_urb);

	/* reset the endpoint toggle */
	usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);

	return 0;
}

/*
 * Get the pipe settings.
 */
static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
    struct usb_interface *intf)
{
	struct usb_host_interface *altsetting = intf->cur_altsetting;
	struct usb_endpoint_descriptor *ep_in = NULL;
	struct usb_endpoint_descriptor *ep_out = NULL;
	struct usb_endpoint_descriptor *ep;
	int i;

	/*
	 * Find the endpoints we need.
	 * We are expecting a minimum of 2 endpoints - in and out (bulk).
	 * We will ignore any others.
	 */
	for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
		ep = &altsetting->endpoint[i].desc;

		/* Is it a BULK endpoint? */
		if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
				== USB_ENDPOINT_XFER_BULK) {
			/* BULK in or out? */
			if (ep->bEndpointAddress & USB_DIR_IN)
				ep_in = ep;
			else
				ep_out = ep;
		}
	}

	if (ep_in == NULL || ep_out == NULL) {
		printk(KERN_NOTICE "%s: failed endpoint check\n",
		    sc->name);
		return -EIO;
	}

	/* Calculate and store the pipe values */
	sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
	sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
	sc->send_bulk_pipe = usb_sndbulkpipe(dev,
		ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	sc->recv_bulk_pipe = usb_rcvbulkpipe(dev, 
		ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);

	return 0;
}

/*
 * Probing is done in the process context, which allows us to cheat
 * and not to build a state machine for the discovery.
 */
static int ub_probe(struct usb_interface *intf,
    const struct usb_device_id *dev_id)
{
	struct ub_dev *sc;
	int nluns;
	int rc;
	int i;

	rc = -ENOMEM;
	if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
		goto err_core;
	memset(sc, 0, sizeof(struct ub_dev));
	spin_lock_init(&sc->lock);
	INIT_LIST_HEAD(&sc->luns);
	usb_init_urb(&sc->work_urb);
	tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
	atomic_set(&sc->poison, 0);

	init_timer(&sc->work_timer);
	sc->work_timer.data = (unsigned long) sc;
	sc->work_timer.function = ub_urb_timeout;

	ub_init_completion(&sc->work_done);
	sc->work_done.done = 1;		/* A little yuk, but oh well... */

	sc->dev = interface_to_usbdev(intf);
	sc->intf = intf;
	// sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
	usb_set_intfdata(intf, sc);
	usb_get_dev(sc->dev);
	// usb_get_intf(sc->intf);	/* Do we need this? */

	snprintf(sc->name, 12, DRV_NAME "(%d.%d)",
	    sc->dev->bus->busnum, sc->dev->devnum);

	/* XXX Verify that we can handle the device (from descriptors) */

	ub_get_pipes(sc, sc->dev, intf);

	if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
		goto err_diag;

	/*
	 * At this point, all USB initialization is done, do upper layer.
	 * We really hate halfway initialized structures, so from the
	 * invariants perspective, this ub_dev is fully constructed at
	 * this point.
	 */

	/*
	 * This is needed to clear toggles. It is a problem only if we do
	 * `rmmod ub && modprobe ub` without disconnects, but we like that.
	 */
#if 0 /* iPod Mini fails if we do this (big white iPod works) */
	ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
	ub_probe_clear_stall(sc, sc->send_bulk_pipe);
#endif

	/*
	 * The way this is used by the startup code is a little specific.
	 * A SCSI check causes a USB stall. Our common case code sees it
	 * and clears the check, after which the device is ready for use.
	 * But if a check was not present, any command other than
	 * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
	 *
	 * If we neglect to clear the SCSI check, the first real command fails
	 * (which is the capacity readout). We clear that and retry, but why
	 * causing spurious retries for no reason.
	 *
	 * Revalidation may start with its own TEST_UNIT_READY, but that one
	 * has to succeed, so we clear checks with an additional one here.
	 * In any case it's not our business how revaliadation is implemented.
	 */
	for (i = 0; i < 3; i++) {	/* Retries for benh's key */
		if ((rc = ub_sync_tur(sc, NULL)) <= 0) break;
		if (rc != 0x6) break;
		msleep(10);
	}

	nluns = 1;
	for (i = 0; i < 3; i++) {
		if ((rc = ub_sync_getmaxlun(sc)) < 0) {
			/* 
			 * This segment is taken from usb-storage. They say
			 * that ZIP-100 needs this, but my own ZIP-100 works
			 * fine without this.
			 * Still, it does not seem to hurt anything.
			 */
			if (rc == -EPIPE) {
				ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
				ub_probe_clear_stall(sc, sc->send_bulk_pipe);
			}
			break;
		}
		if (rc != 0) {
			nluns = rc;
			break;
		}
		msleep(100);
	}

	for (i = 0; i < nluns; i++) {
		ub_probe_lun(sc, i);
	}
	return 0;

	/* device_remove_file(&sc->intf->dev, &dev_attr_diag); */
err_diag:
	usb_set_intfdata(intf, NULL);
	// usb_put_intf(sc->intf);
	usb_put_dev(sc->dev);
	kfree(sc);
err_core:
	return rc;
}

static int ub_probe_lun(struct ub_dev *sc, int lnum)
{
	struct ub_lun *lun;
	request_queue_t *q;
	struct gendisk *disk;
	int rc;

	rc = -ENOMEM;
	if ((lun = kmalloc(sizeof(struct ub_lun), GFP_KERNEL)) == NULL)
		goto err_alloc;
	memset(lun, 0, sizeof(struct ub_lun));
	lun->num = lnum;

	rc = -ENOSR;
	if ((lun->id = ub_id_get()) == -1)
		goto err_id;

	lun->udev = sc;
	list_add(&lun->link, &sc->luns);

	snprintf(lun->name, 16, DRV_NAME "%c(%d.%d.%d)",
	    lun->id + 'a', sc->dev->bus->busnum, sc->dev->devnum, lun->num);

	lun->removable = 1;		/* XXX Query this from the device */
	lun->changed = 1;		/* ub_revalidate clears only */
	lun->first_open = 1;
	ub_revalidate(sc, lun);

	rc = -ENOMEM;
	if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
		goto err_diskalloc;

	lun->disk = disk;
	sprintf(disk->disk_name, DRV_NAME "%c", lun->id + 'a');
	sprintf(disk->devfs_name, DEVFS_NAME "/%c", lun->id + 'a');
	disk->major = UB_MAJOR;
	disk->first_minor = lun->id * UB_MINORS_PER_MAJOR;
	disk->fops = &ub_bd_fops;
	disk->private_data = lun;
	disk->driverfs_dev = &sc->intf->dev;

	rc = -ENOMEM;
	if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL)
		goto err_blkqinit;

	disk->queue = q;

	blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
	blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
	blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
	blk_queue_segment_boundary(q, 0xffffffff);	/* Dubious. */
	blk_queue_max_sectors(q, UB_MAX_SECTORS);
	blk_queue_hardsect_size(q, lun->capacity.bsize);

	q->queuedata = lun;

	set_capacity(disk, lun->capacity.nsec);
	if (lun->removable)
		disk->flags |= GENHD_FL_REMOVABLE;

	add_disk(disk);

	return 0;

err_blkqinit:
	put_disk(disk);
err_diskalloc:
	list_del(&lun->link);
	ub_id_put(lun->id);
err_id:
	kfree(lun);
err_alloc:
	return rc;
}

static void ub_disconnect(struct usb_interface *intf)
{
	struct ub_dev *sc = usb_get_intfdata(intf);
	struct list_head *p;
	struct ub_lun *lun;
	struct gendisk *disk;
	unsigned long flags;

	/*
	 * Prevent ub_bd_release from pulling the rug from under us.
	 * XXX This is starting to look like a kref.
	 * XXX Why not to take this ref at probe time?
	 */
	spin_lock_irqsave(&ub_lock, flags);
	sc->openc++;
	spin_unlock_irqrestore(&ub_lock, flags);

	/*
	 * Fence stall clearnings, operations triggered by unlinkings and so on.
	 * We do not attempt to unlink any URBs, because we do not trust the
	 * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
	 */
	atomic_set(&sc->poison, 1);

	/*
	 * Blow away queued commands.
	 *
	 * Actually, this never works, because before we get here
	 * the HCD terminates outstanding URB(s). It causes our
	 * SCSI command queue to advance, commands fail to submit,
	 * and the whole queue drains. So, we just use this code to
	 * print warnings.
	 */
	spin_lock_irqsave(&sc->lock, flags);
	{
		struct ub_scsi_cmd *cmd;
		int cnt = 0;
		while ((cmd = ub_cmdq_pop(sc)) != NULL) {
			cmd->error = -ENOTCONN;
			cmd->state = UB_CMDST_DONE;
			ub_cmdtr_state(sc, cmd);
			ub_cmdq_pop(sc);
			(*cmd->done)(sc, cmd);
			cnt++;
		}
		if (cnt != 0) {
			printk(KERN_WARNING "%s: "
			    "%d was queued after shutdown\n", sc->name, cnt);
		}
	}
	spin_unlock_irqrestore(&sc->lock, flags);

	/*
	 * Unregister the upper layer.
	 */
	list_for_each (p, &sc->luns) {
		lun = list_entry(p, struct ub_lun, link);
		disk = lun->disk;
		if (disk->flags & GENHD_FL_UP)
			del_gendisk(disk);
		/*
		 * I wish I could do:
		 *    set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
		 * As it is, we rely on our internal poisoning and let
		 * the upper levels to spin furiously failing all the I/O.
		 */
	}

	/*
	 * Taking a lock on a structure which is about to be freed
	 * is very nonsensual. Here it is largely a way to do a debug freeze,
	 * and a bracket which shows where the nonsensual code segment ends.
	 *
	 * Testing for -EINPROGRESS is always a bug, so we are bending
	 * the rules a little.
	 */
	spin_lock_irqsave(&sc->lock, flags);
	if (sc->work_urb.status == -EINPROGRESS) {	/* janitors: ignore */
		printk(KERN_WARNING "%s: "
		    "URB is active after disconnect\n", sc->name);
	}
	spin_unlock_irqrestore(&sc->lock, flags);

	/*
	 * There is virtually no chance that other CPU runs times so long
	 * after ub_urb_complete should have called del_timer, but only if HCD
	 * didn't forget to deliver a callback on unlink.
	 */
	del_timer_sync(&sc->work_timer);

	/*
	 * At this point there must be no commands coming from anyone
	 * and no URBs left in transit.
	 */

	device_remove_file(&sc->intf->dev, &dev_attr_diag);
	usb_set_intfdata(intf, NULL);
	// usb_put_intf(sc->intf);
	sc->intf = NULL;
	usb_put_dev(sc->dev);
	sc->dev = NULL;

	ub_put(sc);
}

static struct usb_driver ub_driver = {
	.owner =	THIS_MODULE,
	.name =		"ub",
	.probe =	ub_probe,
	.disconnect =	ub_disconnect,
	.id_table =	ub_usb_ids,
};

static int __init ub_init(void)
{
	int rc;

	if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
		goto err_regblkdev;
	devfs_mk_dir(DEVFS_NAME);

	if ((rc = usb_register(&ub_driver)) != 0)
		goto err_register;

	return 0;

err_register:
	devfs_remove(DEVFS_NAME);
	unregister_blkdev(UB_MAJOR, DRV_NAME);
err_regblkdev:
	return rc;
}

static void __exit ub_exit(void)
{
	usb_deregister(&ub_driver);

	devfs_remove(DEVFS_NAME);
	unregister_blkdev(UB_MAJOR, DRV_NAME);
}

module_init(ub_init);
module_exit(ub_exit);

MODULE_LICENSE("GPL");