usblp.c

来自「linux 内核源代码」· C语言 代码 · 共 1,436 行 · 第 1/3 页

	poll_wait(file, &usblp->rwait, wait);
	poll_wait(file, &usblp->wwait, wait);
	spin_lock_irqsave(&usblp->lock, flags);
	ret = ((usblp->bidir && usblp->rcomplete) ? POLLIN  | POLLRDNORM : 0) |
	   ((usblp->no_paper || usblp->wcomplete) ? POLLOUT | POLLWRNORM : 0);
	spin_unlock_irqrestore(&usblp->lock, flags);
	return ret;
}

static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct usblp *usblp = file->private_data;
	int length, err, i;
	unsigned char newChannel;
	int status;
	int twoints[2];
	int retval = 0;

	mutex_lock (&usblp->mut);
	if (!usblp->present) {
		retval = -ENODEV;
		goto done;
	}

	if (usblp->sleeping) {
		retval = -ENODEV;
		goto done;
	}

	dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
		_IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );

	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */

		switch (_IOC_NR(cmd)) {

			case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
				if (_IOC_DIR(cmd) != _IOC_READ) {
					retval = -EINVAL;
					goto done;
				}

				length = usblp_cache_device_id_string(usblp);
				if (length < 0) {
					retval = length;
					goto done;
				}
				if (length > _IOC_SIZE(cmd))
					length = _IOC_SIZE(cmd); /* truncate */

				if (copy_to_user((void __user *) arg,
						usblp->device_id_string,
						(unsigned long) length)) {
					retval = -EFAULT;
					goto done;
				}

				break;

			case IOCNR_GET_PROTOCOLS:
				if (_IOC_DIR(cmd) != _IOC_READ ||
				    _IOC_SIZE(cmd) < sizeof(twoints)) {
					retval = -EINVAL;
					goto done;
				}

				twoints[0] = usblp->current_protocol;
				twoints[1] = 0;
				for (i = USBLP_FIRST_PROTOCOL;
				     i <= USBLP_LAST_PROTOCOL; i++) {
					if (usblp->protocol[i].alt_setting >= 0)
						twoints[1] |= (1<<i);
				}

				if (copy_to_user((void __user *)arg,
						(unsigned char *)twoints,
						sizeof(twoints))) {
					retval = -EFAULT;
					goto done;
				}

				break;

			case IOCNR_SET_PROTOCOL:
				if (_IOC_DIR(cmd) != _IOC_WRITE) {
					retval = -EINVAL;
					goto done;
				}

#ifdef DEBUG
				if (arg == -10) {
					usblp_dump(usblp);
					break;
				}
#endif

				usblp_unlink_urbs(usblp);
				retval = usblp_set_protocol(usblp, arg);
				if (retval < 0) {
					usblp_set_protocol(usblp,
						usblp->current_protocol);
				}
				break;

			case IOCNR_HP_SET_CHANNEL:
				if (_IOC_DIR(cmd) != _IOC_WRITE ||
				    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
				    usblp->quirks & USBLP_QUIRK_BIDIR) {
					retval = -EINVAL;
					goto done;
				}

				err = usblp_hp_channel_change_request(usblp,
					arg, &newChannel);
				if (err < 0) {
					err("usblp%d: error = %d setting "
						"HP channel",
						usblp->minor, err);
					retval = -EIO;
					goto done;
				}

				dbg("usblp%d requested/got HP channel %ld/%d",
					usblp->minor, arg, newChannel);
				break;

			case IOCNR_GET_BUS_ADDRESS:
				if (_IOC_DIR(cmd) != _IOC_READ ||
				    _IOC_SIZE(cmd) < sizeof(twoints)) {
					retval = -EINVAL;
					goto done;
				}

				twoints[0] = usblp->dev->bus->busnum;
				twoints[1] = usblp->dev->devnum;
				if (copy_to_user((void __user *)arg,
						(unsigned char *)twoints,
						sizeof(twoints))) {
					retval = -EFAULT;
					goto done;
				}

				dbg("usblp%d is bus=%d, device=%d",
					usblp->minor, twoints[0], twoints[1]);
				break;

			case IOCNR_GET_VID_PID:
				if (_IOC_DIR(cmd) != _IOC_READ ||
				    _IOC_SIZE(cmd) < sizeof(twoints)) {
					retval = -EINVAL;
					goto done;
				}

				twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
				twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
				if (copy_to_user((void __user *)arg,
						(unsigned char *)twoints,
						sizeof(twoints))) {
					retval = -EFAULT;
					goto done;
				}

				dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
					usblp->minor, twoints[0], twoints[1]);
				break;

			case IOCNR_SOFT_RESET:
				if (_IOC_DIR(cmd) != _IOC_NONE) {
					retval = -EINVAL;
					goto done;
				}
				retval = usblp_reset(usblp);
				break;
			default:
				retval = -ENOTTY;
		}
	else	/* old-style ioctl value */
		switch (cmd) {

			case LPGETSTATUS:
				if ((retval = usblp_read_status(usblp, usblp->statusbuf))) {
					if (printk_ratelimit())
						printk(KERN_ERR "usblp%d:"
						    "failed reading printer status (%d)\n",
						    usblp->minor, retval);
					retval = -EIO;
					goto done;
				}
				status = *usblp->statusbuf;
				if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
					retval = -EFAULT;
				break;

			case LPABORT:
				if (arg)
					usblp->flags |= LP_ABORT;
				else
					usblp->flags &= ~LP_ABORT;
				break;

			default:
				retval = -ENOTTY;
		}

done:
	mutex_unlock (&usblp->mut);
	return retval;
}

static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
{
	struct urb *urb;
	char *writebuf;

	if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
		return NULL;
	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
		kfree(writebuf);
		return NULL;
	}

	usb_fill_bulk_urb(urb, usblp->dev,
		usb_sndbulkpipe(usblp->dev,
		 usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
		writebuf, transfer_length, usblp_bulk_write, usblp);
	urb->transfer_flags |= URB_FREE_BUFFER;

	return urb;
}

static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	struct usblp *usblp = file->private_data;
	struct urb *writeurb;
	int rv;
	int transfer_length;
	ssize_t writecount = 0;

	if (mutex_lock_interruptible(&usblp->wmut)) {
		rv = -EINTR;
		goto raise_biglock;
	}
	if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
		goto raise_wait;

	while (writecount < count) {
		/*
		 * Step 1: Submit next block.
		 */
		if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
			transfer_length = USBLP_BUF_SIZE;

		rv = -ENOMEM;
		if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
			goto raise_urb;
		usb_anchor_urb(writeurb, &usblp->urbs);

		if (copy_from_user(writeurb->transfer_buffer,
				   buffer + writecount, transfer_length)) {
			rv = -EFAULT;
			goto raise_badaddr;
		}

		spin_lock_irq(&usblp->lock);
		usblp->wcomplete = 0;
		spin_unlock_irq(&usblp->lock);
		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
			usblp->wstatus = 0;
			spin_lock_irq(&usblp->lock);
			usblp->no_paper = 0;
			usblp->wcomplete = 1;
			wake_up(&usblp->wwait);
			spin_unlock_irq(&usblp->lock);
			if (rv != -ENOMEM)
				rv = -EIO;
			goto raise_submit;
		}

		/*
		 * Step 2: Wait for transfer to end, collect results.
		 */
		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
		if (rv < 0) {
			if (rv == -EAGAIN) {
				/* Presume that it's going to complete well. */
				writecount += transfer_length;
			}
			if (rv == -ENOSPC) {
				spin_lock_irq(&usblp->lock);
				usblp->no_paper = 1;	/* Mark for poll(2) */
				spin_unlock_irq(&usblp->lock);
				writecount += transfer_length;
			}
			/* Leave URB dangling, to be cleaned on close. */
			goto collect_error;
		}

		if (usblp->wstatus < 0) {
			rv = -EIO;
			goto collect_error;
		}
		/*
		 * This is critical: it must be our URB, not other writer's.
		 * The wmut exists mainly to cover us here.
		 */
		writecount += usblp->wstatus;
	}

	mutex_unlock(&usblp->wmut);
	return writecount;

raise_submit:
raise_badaddr:
	usb_unanchor_urb(writeurb);
	usb_free_urb(writeurb);
raise_urb:
raise_wait:
collect_error:		/* Out of raise sequence */
	mutex_unlock(&usblp->wmut);
raise_biglock:
	return writecount ? writecount : rv;
}

/*
 * Notice that we fail to restart in a few cases: on EFAULT, on restart
 * error, etc. This is the historical behaviour. In all such cases we return
 * EIO, and applications loop in order to get the new read going.
 */
static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
{
	struct usblp *usblp = file->private_data;
	ssize_t count;
	ssize_t avail;
	int rv;

	if (!usblp->bidir)
		return -EINVAL;

	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
	if (rv < 0)
		return rv;

	if ((avail = usblp->rstatus) < 0) {
		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
		    usblp->minor, (int)avail);
		usblp_submit_read(usblp);
		count = -EIO;
		goto done;
	}

	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
	if (count != 0 &&
	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
		count = -EFAULT;
		goto done;
	}

	if ((usblp->readcount += count) == avail) {
		if (usblp_submit_read(usblp) < 0) {
			/* We don't want to leak USB return codes into errno. */
			if (count == 0)
				count = -EIO;
			goto done;
		}
	}

done:
	mutex_unlock (&usblp->mut);
	return count;
}

/*
 * Wait for the write path to come idle.
 * This is called under the ->wmut, so the idle path stays idle.
 *
 * Our write path has a peculiar property: it does not buffer like a tty,
 * but waits for the write to succeed. This allows our ->release to bug out
 * without waiting for writes to drain. But it obviously does not work
 * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
 * select(2) or poll(2) to wait for the buffer to drain before closing.
 * Alternatively, set blocking mode with fcntl and issue a zero-size write.
 */
static int usblp_wwait(struct usblp *usblp, int nonblock)
{
	DECLARE_WAITQUEUE(waita, current);
	int rc;
	int err = 0;

	add_wait_queue(&usblp->wwait, &waita);
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (mutex_lock_interruptible(&usblp->mut)) {
			rc = -EINTR;
			break;
		}
		rc = usblp_wtest(usblp, nonblock);
		mutex_unlock(&usblp->mut);
		if (rc <= 0)
			break;

		if (usblp->flags & LP_ABORT) {
			if (schedule_timeout(msecs_to_jiffies(5000)) == 0) {
				err = usblp_check_status(usblp, err);
				if (err == 1) {	/* Paper out */
					rc = -ENOSPC;
					break;
				}
			}
		} else {
			schedule();
		}
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&usblp->wwait, &waita);
	return rc;
}

static int usblp_wtest(struct usblp *usblp, int nonblock)
{
	unsigned long flags;

	if (!usblp->present)
		return -ENODEV;
	if (signal_pending(current))
		return -EINTR;
	spin_lock_irqsave(&usblp->lock, flags);
	if (usblp->wcomplete) {
		spin_unlock_irqrestore(&usblp->lock, flags);
		return 0;
	}
	spin_unlock_irqrestore(&usblp->lock, flags);
	if (usblp->sleeping)
		return -ENODEV;
	if (nonblock)
		return -EAGAIN;
	return 1;
}

/*
 * Wait for read bytes to become available. This probably should have been
 * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
 * name for functions which lock and return.
 *
 * We do not use wait_event_interruptible because it makes locking iffy.
 */
static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
{
	DECLARE_WAITQUEUE(waita, current);
	int rc;

	add_wait_queue(&usblp->rwait, &waita);
	for (;;) {
		if (mutex_lock_interruptible(&usblp->mut)) {
			rc = -EINTR;
			break;
		}
		set_current_state(TASK_INTERRUPTIBLE);
		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
			mutex_unlock(&usblp->mut);
			break;
		}
		if (rc == 0)	/* Keep it locked */
			break;
		mutex_unlock(&usblp->mut);
		schedule();
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&usblp->rwait, &waita);
	return rc;
}

static int usblp_rtest(struct usblp *usblp, int nonblock)
{
	unsigned long flags;

	if (!usblp->present)
		return -ENODEV;
	if (signal_pending(current))
		return -EINTR;