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