1 // SPDX-License-Identifier: GPL-2.0
3  * USB Skeleton driver - 2.2
5  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
7  * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
37 #define MAX_TRANSFER		(PAGE_SIZE - 512)
46 /* Structure to hold all of our device specific stuff */
59 	int			errors;			/* the last request tanked */  member
61 	spinlock_t		err_lock;		/* lock for errors */
76 	usb_free_urb(dev->bulk_in_urb);  in skel_delete()
77 	usb_put_intf(dev->interface);  in skel_delete()
78 	usb_put_dev(dev->udev);  in skel_delete()
79 	kfree(dev->bulk_in_buffer);  in skel_delete()
94 		pr_err("%s - error, can't find device for minor %d\n",  in skel_open()
96 		retval = -ENODEV;  in skel_open()
102 		retval = -ENODEV;  in skel_open()
111 	kref_get(&dev->kref);  in skel_open()
114 	file->private_data = dev;  in skel_open()
124 	dev = file->private_data;  in skel_release()
126 		return -ENODEV;  in skel_release()
129 	usb_autopm_put_interface(dev->interface);  in skel_release()
132 	kref_put(&dev->kref, skel_delete);  in skel_release()
141 	dev = file->private_data;  in skel_flush()
143 		return -ENODEV;  in skel_flush()
146 	mutex_lock(&dev->io_mutex);  in skel_flush()
149 	/* read out errors, leave subsequent opens a clean slate */  in skel_flush()
150 	spin_lock_irq(&dev->err_lock);  in skel_flush()
151 	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;  in skel_flush()
152 	dev->errors = 0;  in skel_flush()
153 	spin_unlock_irq(&dev->err_lock);  in skel_flush()
155 	mutex_unlock(&dev->io_mutex);  in skel_flush()
165 	dev = urb->context;  in skel_read_bulk_callback()
167 	spin_lock_irqsave(&dev->err_lock, flags);  in skel_read_bulk_callback()
168 	/* sync/async unlink faults aren't errors */  in skel_read_bulk_callback()
169 	if (urb->status) {  in skel_read_bulk_callback()
170 		if (!(urb->status == -ENOENT ||  in skel_read_bulk_callback()
171 		    urb->status == -ECONNRESET ||  in skel_read_bulk_callback()
172 		    urb->status == -ESHUTDOWN))  in skel_read_bulk_callback()
173 			dev_err(&dev->interface->dev,  in skel_read_bulk_callback()
174 				"%s - nonzero write bulk status received: %d\n",  in skel_read_bulk_callback()
175 				__func__, urb->status);  in skel_read_bulk_callback()
177 		dev->errors = urb->status;  in skel_read_bulk_callback()
179 		dev->bulk_in_filled = urb->actual_length;  in skel_read_bulk_callback()
181 	dev->ongoing_read = 0;  in skel_read_bulk_callback()
182 	spin_unlock_irqrestore(&dev->err_lock, flags);  in skel_read_bulk_callback()
184 	wake_up_interruptible(&dev->bulk_in_wait);  in skel_read_bulk_callback()
192 	usb_fill_bulk_urb(dev->bulk_in_urb,  in skel_do_read_io()
193 			dev->udev,  in skel_do_read_io()
194 			usb_rcvbulkpipe(dev->udev,  in skel_do_read_io()
195 				dev->bulk_in_endpointAddr),  in skel_do_read_io()
196 			dev->bulk_in_buffer,  in skel_do_read_io()
197 			min(dev->bulk_in_size, count),  in skel_do_read_io()
201 	spin_lock_irq(&dev->err_lock);  in skel_do_read_io()
202 	dev->ongoing_read = 1;  in skel_do_read_io()
203 	spin_unlock_irq(&dev->err_lock);  in skel_do_read_io()
206 	dev->bulk_in_filled = 0;  in skel_do_read_io()
207 	dev->bulk_in_copied = 0;  in skel_do_read_io()
210 	rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);  in skel_do_read_io()
212 		dev_err(&dev->interface->dev,  in skel_do_read_io()
213 			"%s - failed submitting read urb, error %d\n",  in skel_do_read_io()
215 		rv = (rv == -ENOMEM) ? rv : -EIO;  in skel_do_read_io()
216 		spin_lock_irq(&dev->err_lock);  in skel_do_read_io()
217 		dev->ongoing_read = 0;  in skel_do_read_io()
218 		spin_unlock_irq(&dev->err_lock);  in skel_do_read_io()
231 	dev = file->private_data;  in skel_read()
237 	rv = mutex_lock_interruptible(&dev->io_mutex);  in skel_read()
241 	if (dev->disconnected) {		/* disconnect() was called */  in skel_read()
242 		rv = -ENODEV;  in skel_read()
247 retry:  in skel_read()
248 	spin_lock_irq(&dev->err_lock);  in skel_read()
249 	ongoing_io = dev->ongoing_read;  in skel_read()
250 	spin_unlock_irq(&dev->err_lock);  in skel_read()
254 		if (file->f_flags & O_NONBLOCK) {  in skel_read()
255 			rv = -EAGAIN;  in skel_read()
262 		rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));  in skel_read()
267 	/* errors must be reported */  in skel_read()
268 	rv = dev->errors;  in skel_read()
271 		dev->errors = 0;  in skel_read()
273 		rv = (rv == -EPIPE) ? rv : -EIO;  in skel_read()
283 	if (dev->bulk_in_filled) {  in skel_read()
285 		size_t available = dev->bulk_in_filled - dev->bulk_in_copied;  in skel_read()
290 			 * all data has been used  in skel_read()
297 				goto retry;  in skel_read()
305 				 dev->bulk_in_buffer + dev->bulk_in_copied,  in skel_read()
307 			rv = -EFAULT;  in skel_read()
311 		dev->bulk_in_copied += chunk;  in skel_read()
318 			skel_do_read_io(dev, count - chunk);  in skel_read()
325 			goto retry;  in skel_read()
328 	mutex_unlock(&dev->io_mutex);  in skel_read()
337 	dev = urb->context;  in skel_write_bulk_callback()
339 	/* sync/async unlink faults aren't errors */  in skel_write_bulk_callback()
340 	if (urb->status) {  in skel_write_bulk_callback()
341 		if (!(urb->status == -ENOENT ||  in skel_write_bulk_callback()
342 		    urb->status == -ECONNRESET ||  in skel_write_bulk_callback()
343 		    urb->status == -ESHUTDOWN))  in skel_write_bulk_callback()
344 			dev_err(&dev->interface->dev,  in skel_write_bulk_callback()
345 				"%s - nonzero write bulk status received: %d\n",  in skel_write_bulk_callback()
346 				__func__, urb->status);  in skel_write_bulk_callback()
348 		spin_lock_irqsave(&dev->err_lock, flags);  in skel_write_bulk_callback()
349 		dev->errors = urb->status;  in skel_write_bulk_callback()
350 		spin_unlock_irqrestore(&dev->err_lock, flags);  in skel_write_bulk_callback()
354 	usb_free_coherent(urb->dev, urb->transfer_buffer_length,  in skel_write_bulk_callback()
355 			  urb->transfer_buffer, urb->transfer_dma);  in skel_write_bulk_callback()
356 	up(&dev->limit_sem);  in skel_write_bulk_callback()
368 	dev = file->private_data;  in skel_write()
375 	 * limit the number of URBs in flight to stop a user from using up all  in skel_write()
378 	if (!(file->f_flags & O_NONBLOCK)) {  in skel_write()
379 		if (down_interruptible(&dev->limit_sem)) {  in skel_write()
380 			retval = -ERESTARTSYS;  in skel_write()
384 		if (down_trylock(&dev->limit_sem)) {  in skel_write()
385 			retval = -EAGAIN;  in skel_write()
390 	spin_lock_irq(&dev->err_lock);  in skel_write()
391 	retval = dev->errors;  in skel_write()
394 		dev->errors = 0;  in skel_write()
396 		retval = (retval == -EPIPE) ? retval : -EIO;  in skel_write()
398 	spin_unlock_irq(&dev->err_lock);  in skel_write()
405 		retval = -ENOMEM;  in skel_write()
409 	buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL,  in skel_write()
410 				 &urb->transfer_dma);  in skel_write()
412 		retval = -ENOMEM;  in skel_write()
417 		retval = -EFAULT;  in skel_write()
422 	mutex_lock(&dev->io_mutex);  in skel_write()
423 	if (dev->disconnected) {		/* disconnect() was called */  in skel_write()
424 		mutex_unlock(&dev->io_mutex);  in skel_write()
425 		retval = -ENODEV;  in skel_write()
430 	usb_fill_bulk_urb(urb, dev->udev,  in skel_write()
431 			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),  in skel_write()
433 	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;  in skel_write()
434 	usb_anchor_urb(urb, &dev->submitted);  in skel_write()
438 	mutex_unlock(&dev->io_mutex);  in skel_write()
440 		dev_err(&dev->interface->dev,  in skel_write()
441 			"%s - failed submitting write urb, error %d\n",  in skel_write()
459 		usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);  in skel_write()
462 	up(&dev->limit_sem);  in skel_write()
498 		return -ENOMEM;  in skel_probe()
500 	kref_init(&dev->kref);  in skel_probe()
501 	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);  in skel_probe()
502 	mutex_init(&dev->io_mutex);  in skel_probe()
503 	spin_lock_init(&dev->err_lock);  in skel_probe()
504 	init_usb_anchor(&dev->submitted);  in skel_probe()
505 	init_waitqueue_head(&dev->bulk_in_wait);  in skel_probe()
507 	dev->udev = usb_get_dev(interface_to_usbdev(interface));  in skel_probe()
508 	dev->interface = usb_get_intf(interface);  in skel_probe()
511 	/* use only the first bulk-in and bulk-out endpoints */  in skel_probe()
512 	retval = usb_find_common_endpoints(interface->cur_altsetting,  in skel_probe()
515 		dev_err(&interface->dev,  in skel_probe()
516 			"Could not find both bulk-in and bulk-out endpoints\n");  in skel_probe()
520 	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);  in skel_probe()
521 	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;  in skel_probe()
522 	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);  in skel_probe()
523 	if (!dev->bulk_in_buffer) {  in skel_probe()
524 		retval = -ENOMEM;  in skel_probe()
527 	dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);  in skel_probe()
528 	if (!dev->bulk_in_urb) {  in skel_probe()
529 		retval = -ENOMEM;  in skel_probe()
533 	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;  in skel_probe()
542 		dev_err(&interface->dev,  in skel_probe()
549 	dev_info(&interface->dev,  in skel_probe()
550 		 "USB Skeleton device now attached to USBSkel-%d",  in skel_probe()
551 		 interface->minor);  in skel_probe()
556 	kref_put(&dev->kref, skel_delete);  in skel_probe()
564 	int minor = interface->minor;  in skel_disconnect()
572 	mutex_lock(&dev->io_mutex);  in skel_disconnect()
573 	dev->disconnected = 1;  in skel_disconnect()
574 	mutex_unlock(&dev->io_mutex);  in skel_disconnect()
576 	usb_kill_urb(dev->bulk_in_urb);  in skel_disconnect()
577 	usb_kill_anchored_urbs(&dev->submitted);  in skel_disconnect()
580 	kref_put(&dev->kref, skel_delete);  in skel_disconnect()
582 	dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);  in skel_disconnect()
589 	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);  in skel_draw_down()
591 		usb_kill_anchored_urbs(&dev->submitted);  in skel_draw_down()
592 	usb_kill_urb(dev->bulk_in_urb);  in skel_draw_down()
614 	mutex_lock(&dev->io_mutex);  in skel_pre_reset()
624 	/* we are sure no URBs are active - no locking needed */  in skel_post_reset()
625 	dev->errors = -EPIPE;  in skel_post_reset()
626 	mutex_unlock(&dev->io_mutex);  in skel_post_reset()