1/*****************************************************************************
2 *                          USBLCD Kernel Driver                             *
3 *                            Version 1.05                                   *
4 *             (C) 2005 Georges Toth <g.toth@e-biz.lu>                       *
5 *                                                                           *
6 *     This file is licensed under the GPL. See COPYING in the package.      *
7 * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com)        *
8 *                                                                           *
9 *                                                                           *
10 * 28.02.05 Complete rewrite of the original usblcd.c driver,                *
11 *          based on usb_skeleton.c.                                         *
12 *          This new driver allows more than one USB-LCD to be connected     *
13 *          and controlled, at once                                          *
14 *****************************************************************************/
15#include <linux/module.h>
16#include <linux/kernel.h>
17#include <linux/slab.h>
18#include <linux/errno.h>
19#include <linux/mutex.h>
20#include <linux/uaccess.h>
21#include <linux/usb.h>
22
23#define DRIVER_VERSION "USBLCD Driver Version 1.05"
24
25#define USBLCD_MINOR		144
26
27#define IOCTL_GET_HARD_VERSION	1
28#define IOCTL_GET_DRV_VERSION	2
29
30
31static DEFINE_MUTEX(lcd_mutex);
32static const struct usb_device_id id_table[] = {
33	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
34	{ },
35};
36MODULE_DEVICE_TABLE(usb, id_table);
37
38static DEFINE_MUTEX(open_disc_mutex);
39
40
41struct usb_lcd {
42	struct usb_device	*udev;			/* init: probe_lcd */
43	struct usb_interface	*interface;		/* the interface for
44							   this device */
45	unsigned char		*bulk_in_buffer;	/* the buffer to receive
46							   data */
47	size_t			bulk_in_size;		/* the size of the
48							   receive buffer */
49	__u8			bulk_in_endpointAddr;	/* the address of the
50							   bulk in endpoint */
51	__u8			bulk_out_endpointAddr;	/* the address of the
52							   bulk out endpoint */
53	struct kref		kref;
54	struct semaphore	limit_sem;		/* to stop writes at
55							   full throttle from
56							   using up all RAM */
57	struct usb_anchor	submitted;		/* URBs to wait for
58							   before suspend */
59};
60#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
61
62#define USB_LCD_CONCURRENT_WRITES	5
63
64static struct usb_driver lcd_driver;
65
66
67static void lcd_delete(struct kref *kref)
68{
69	struct usb_lcd *dev = to_lcd_dev(kref);
70
71	usb_put_dev(dev->udev);
72	kfree(dev->bulk_in_buffer);
73	kfree(dev);
74}
75
76
77static int lcd_open(struct inode *inode, struct file *file)
78{
79	struct usb_lcd *dev;
80	struct usb_interface *interface;
81	int subminor, r;
82
83	mutex_lock(&lcd_mutex);
84	subminor = iminor(inode);
85
86	interface = usb_find_interface(&lcd_driver, subminor);
87	if (!interface) {
88		mutex_unlock(&lcd_mutex);
89		printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n",
90		       __func__, subminor);
91		return -ENODEV;
92	}
93
94	mutex_lock(&open_disc_mutex);
95	dev = usb_get_intfdata(interface);
96	if (!dev) {
97		mutex_unlock(&open_disc_mutex);
98		mutex_unlock(&lcd_mutex);
99		return -ENODEV;
100	}
101
102	/* increment our usage count for the device */
103	kref_get(&dev->kref);
104	mutex_unlock(&open_disc_mutex);
105
106	/* grab a power reference */
107	r = usb_autopm_get_interface(interface);
108	if (r < 0) {
109		kref_put(&dev->kref, lcd_delete);
110		mutex_unlock(&lcd_mutex);
111		return r;
112	}
113
114	/* save our object in the file's private structure */
115	file->private_data = dev;
116	mutex_unlock(&lcd_mutex);
117
118	return 0;
119}
120
121static int lcd_release(struct inode *inode, struct file *file)
122{
123	struct usb_lcd *dev;
124
125	dev = file->private_data;
126	if (dev == NULL)
127		return -ENODEV;
128
129	/* decrement the count on our device */
130	usb_autopm_put_interface(dev->interface);
131	kref_put(&dev->kref, lcd_delete);
132	return 0;
133}
134
135static ssize_t lcd_read(struct file *file, char __user * buffer,
136			size_t count, loff_t *ppos)
137{
138	struct usb_lcd *dev;
139	int retval = 0;
140	int bytes_read;
141
142	dev = file->private_data;
143
144	/* do a blocking bulk read to get data from the device */
145	retval = usb_bulk_msg(dev->udev,
146			      usb_rcvbulkpipe(dev->udev,
147					      dev->bulk_in_endpointAddr),
148			      dev->bulk_in_buffer,
149			      min(dev->bulk_in_size, count),
150			      &bytes_read, 10000);
151
152	/* if the read was successful, copy the data to userspace */
153	if (!retval) {
154		if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
155			retval = -EFAULT;
156		else
157			retval = bytes_read;
158	}
159
160	return retval;
161}
162
163static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
164{
165	struct usb_lcd *dev;
166	u16 bcdDevice;
167	char buf[30];
168
169	dev = file->private_data;
170	if (dev == NULL)
171		return -ENODEV;
172
173	switch (cmd) {
174	case IOCTL_GET_HARD_VERSION:
175		mutex_lock(&lcd_mutex);
176		bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
177		sprintf(buf, "%1d%1d.%1d%1d",
178			(bcdDevice & 0xF000)>>12,
179			(bcdDevice & 0xF00)>>8,
180			(bcdDevice & 0xF0)>>4,
181			(bcdDevice & 0xF));
182		mutex_unlock(&lcd_mutex);
183		if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
184			return -EFAULT;
185		break;
186	case IOCTL_GET_DRV_VERSION:
187		sprintf(buf, DRIVER_VERSION);
188		if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
189			return -EFAULT;
190		break;
191	default:
192		return -ENOTTY;
193		break;
194	}
195
196	return 0;
197}
198
199static void lcd_write_bulk_callback(struct urb *urb)
200{
201	struct usb_lcd *dev;
202	int status = urb->status;
203
204	dev = urb->context;
205
206	/* sync/async unlink faults aren't errors */
207	if (status &&
208	    !(status == -ENOENT ||
209	      status == -ECONNRESET ||
210	      status == -ESHUTDOWN)) {
211		dev_dbg(&dev->interface->dev,
212			"nonzero write bulk status received: %d\n", status);
213	}
214
215	/* free up our allocated buffer */
216	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
217			  urb->transfer_buffer, urb->transfer_dma);
218	up(&dev->limit_sem);
219}
220
221static ssize_t lcd_write(struct file *file, const char __user * user_buffer,
222			 size_t count, loff_t *ppos)
223{
224	struct usb_lcd *dev;
225	int retval = 0, r;
226	struct urb *urb = NULL;
227	char *buf = NULL;
228
229	dev = file->private_data;
230
231	/* verify that we actually have some data to write */
232	if (count == 0)
233		goto exit;
234
235	r = down_interruptible(&dev->limit_sem);
236	if (r < 0)
237		return -EINTR;
238
239	/* create a urb, and a buffer for it, and copy the data to the urb */
240	urb = usb_alloc_urb(0, GFP_KERNEL);
241	if (!urb) {
242		retval = -ENOMEM;
243		goto err_no_buf;
244	}
245
246	buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
247				 &urb->transfer_dma);
248	if (!buf) {
249		retval = -ENOMEM;
250		goto error;
251	}
252
253	if (copy_from_user(buf, user_buffer, count)) {
254		retval = -EFAULT;
255		goto error;
256	}
257
258	/* initialize the urb properly */
259	usb_fill_bulk_urb(urb, dev->udev,
260			  usb_sndbulkpipe(dev->udev,
261			  dev->bulk_out_endpointAddr),
262			  buf, count, lcd_write_bulk_callback, dev);
263	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
264
265	usb_anchor_urb(urb, &dev->submitted);
266
267	/* send the data out the bulk port */
268	retval = usb_submit_urb(urb, GFP_KERNEL);
269	if (retval) {
270		dev_err(&dev->udev->dev,
271			"%s - failed submitting write urb, error %d\n",
272			__func__, retval);
273		goto error_unanchor;
274	}
275
276	/* release our reference to this urb,
277	   the USB core will eventually free it entirely */
278	usb_free_urb(urb);
279
280exit:
281	return count;
282error_unanchor:
283	usb_unanchor_urb(urb);
284error:
285	usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
286	usb_free_urb(urb);
287err_no_buf:
288	up(&dev->limit_sem);
289	return retval;
290}
291
292static const struct file_operations lcd_fops = {
293	.owner =        THIS_MODULE,
294	.read =         lcd_read,
295	.write =        lcd_write,
296	.open =         lcd_open,
297	.unlocked_ioctl = lcd_ioctl,
298	.release =      lcd_release,
299	.llseek =	 noop_llseek,
300};
301
302/*
303 * usb class driver info in order to get a minor number from the usb core,
304 * and to have the device registered with the driver core
305 */
306static struct usb_class_driver lcd_class = {
307	.name =         "lcd%d",
308	.fops =         &lcd_fops,
309	.minor_base =   USBLCD_MINOR,
310};
311
312static int lcd_probe(struct usb_interface *interface,
313		     const struct usb_device_id *id)
314{
315	struct usb_lcd *dev = NULL;
316	struct usb_host_interface *iface_desc;
317	struct usb_endpoint_descriptor *endpoint;
318	size_t buffer_size;
319	int i;
320	int retval = -ENOMEM;
321
322	/* allocate memory for our device state and initialize it */
323	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
324	if (dev == NULL) {
325		dev_err(&interface->dev, "Out of memory\n");
326		goto error;
327	}
328	kref_init(&dev->kref);
329	sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
330	init_usb_anchor(&dev->submitted);
331
332	dev->udev = usb_get_dev(interface_to_usbdev(interface));
333	dev->interface = interface;
334
335	if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
336		dev_warn(&interface->dev, "USBLCD model not supported.\n");
337		retval = -ENODEV;
338		goto error;
339	}
340
341	/* set up the endpoint information */
342	/* use only the first bulk-in and bulk-out endpoints */
343	iface_desc = interface->cur_altsetting;
344	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
345		endpoint = &iface_desc->endpoint[i].desc;
346
347		if (!dev->bulk_in_endpointAddr &&
348		    usb_endpoint_is_bulk_in(endpoint)) {
349			/* we found a bulk in endpoint */
350			buffer_size = usb_endpoint_maxp(endpoint);
351			dev->bulk_in_size = buffer_size;
352			dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
353			dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
354			if (!dev->bulk_in_buffer) {
355				dev_err(&interface->dev,
356					"Could not allocate bulk_in_buffer\n");
357				goto error;
358			}
359		}
360
361		if (!dev->bulk_out_endpointAddr &&
362		    usb_endpoint_is_bulk_out(endpoint)) {
363			/* we found a bulk out endpoint */
364			dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
365		}
366	}
367	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
368		dev_err(&interface->dev,
369			"Could not find both bulk-in and bulk-out endpoints\n");
370		goto error;
371	}
372
373	/* save our data pointer in this interface device */
374	usb_set_intfdata(interface, dev);
375
376	/* we can register the device now, as it is ready */
377	retval = usb_register_dev(interface, &lcd_class);
378	if (retval) {
379		/* something prevented us from registering this driver */
380		dev_err(&interface->dev,
381			"Not able to get a minor for this device.\n");
382		usb_set_intfdata(interface, NULL);
383		goto error;
384	}
385
386	i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
387
388	dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
389		 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
390		 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
391
392	/* let the user know what node this device is now attached to */
393	dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
394		 interface->minor);
395	return 0;
396
397error:
398	if (dev)
399		kref_put(&dev->kref, lcd_delete);
400	return retval;
401}
402
403static void lcd_draw_down(struct usb_lcd *dev)
404{
405	int time;
406
407	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
408	if (!time)
409		usb_kill_anchored_urbs(&dev->submitted);
410}
411
412static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
413{
414	struct usb_lcd *dev = usb_get_intfdata(intf);
415
416	if (!dev)
417		return 0;
418	lcd_draw_down(dev);
419	return 0;
420}
421
422static int lcd_resume(struct usb_interface *intf)
423{
424	return 0;
425}
426
427static void lcd_disconnect(struct usb_interface *interface)
428{
429	struct usb_lcd *dev;
430	int minor = interface->minor;
431
432	mutex_lock(&open_disc_mutex);
433	dev = usb_get_intfdata(interface);
434	usb_set_intfdata(interface, NULL);
435	mutex_unlock(&open_disc_mutex);
436
437	/* give back our minor */
438	usb_deregister_dev(interface, &lcd_class);
439
440	/* decrement our usage count */
441	kref_put(&dev->kref, lcd_delete);
442
443	dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
444}
445
446static struct usb_driver lcd_driver = {
447	.name =		"usblcd",
448	.probe =	lcd_probe,
449	.disconnect =	lcd_disconnect,
450	.suspend =	lcd_suspend,
451	.resume =	lcd_resume,
452	.id_table =	id_table,
453	.supports_autosuspend = 1,
454};
455
456module_usb_driver(lcd_driver);
457
458MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
459MODULE_DESCRIPTION(DRIVER_VERSION);
460MODULE_LICENSE("GPL");
461