xref: /openbmc/linux/drivers/usb/misc/usblcd.c (revision 57ee11ea)
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 
31 static DEFINE_MUTEX(lcd_mutex);
32 static const struct usb_device_id id_table[] = {
33 	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
34 	{ },
35 };
36 MODULE_DEVICE_TABLE(usb, id_table);
37 
38 static DEFINE_MUTEX(open_disc_mutex);
39 
40 
41 struct 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 
64 static struct usb_driver lcd_driver;
65 
66 
67 static 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 
77 static 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 
121 static 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 
135 static 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 
163 static 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 
199 static 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 
221 static 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 
280 exit:
281 	return count;
282 error_unanchor:
283 	usb_unanchor_urb(urb);
284 error:
285 	usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
286 	usb_free_urb(urb);
287 err_no_buf:
288 	up(&dev->limit_sem);
289 	return retval;
290 }
291 
292 static 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  */
306 static struct usb_class_driver lcd_class = {
307 	.name =         "lcd%d",
308 	.fops =         &lcd_fops,
309 	.minor_base =   USBLCD_MINOR,
310 };
311 
312 static int lcd_probe(struct usb_interface *interface,
313 		     const struct usb_device_id *id)
314 {
315 	struct usb_lcd *dev = NULL;
316 	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
317 	int i;
318 	int retval;
319 
320 	/* allocate memory for our device state and initialize it */
321 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
322 	if (!dev)
323 		return -ENOMEM;
324 
325 	kref_init(&dev->kref);
326 	sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
327 	init_usb_anchor(&dev->submitted);
328 
329 	dev->udev = usb_get_dev(interface_to_usbdev(interface));
330 	dev->interface = interface;
331 
332 	if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
333 		dev_warn(&interface->dev, "USBLCD model not supported.\n");
334 		retval = -ENODEV;
335 		goto error;
336 	}
337 
338 	/* set up the endpoint information */
339 	/* use only the first bulk-in and bulk-out endpoints */
340 	retval = usb_find_common_endpoints(interface->cur_altsetting,
341 			&bulk_in, &bulk_out, NULL, NULL);
342 	if (retval) {
343 		dev_err(&interface->dev,
344 			"Could not find both bulk-in and bulk-out endpoints\n");
345 		goto error;
346 	}
347 
348 	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
349 	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
350 	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
351 	if (!dev->bulk_in_buffer) {
352 		retval = -ENOMEM;
353 		goto error;
354 	}
355 
356 	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
357 
358 	/* save our data pointer in this interface device */
359 	usb_set_intfdata(interface, dev);
360 
361 	/* we can register the device now, as it is ready */
362 	retval = usb_register_dev(interface, &lcd_class);
363 	if (retval) {
364 		/* something prevented us from registering this driver */
365 		dev_err(&interface->dev,
366 			"Not able to get a minor for this device.\n");
367 		usb_set_intfdata(interface, NULL);
368 		goto error;
369 	}
370 
371 	i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
372 
373 	dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
374 		 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
375 		 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
376 
377 	/* let the user know what node this device is now attached to */
378 	dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
379 		 interface->minor);
380 	return 0;
381 
382 error:
383 	kref_put(&dev->kref, lcd_delete);
384 	return retval;
385 }
386 
387 static void lcd_draw_down(struct usb_lcd *dev)
388 {
389 	int time;
390 
391 	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
392 	if (!time)
393 		usb_kill_anchored_urbs(&dev->submitted);
394 }
395 
396 static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
397 {
398 	struct usb_lcd *dev = usb_get_intfdata(intf);
399 
400 	if (!dev)
401 		return 0;
402 	lcd_draw_down(dev);
403 	return 0;
404 }
405 
406 static int lcd_resume(struct usb_interface *intf)
407 {
408 	return 0;
409 }
410 
411 static void lcd_disconnect(struct usb_interface *interface)
412 {
413 	struct usb_lcd *dev;
414 	int minor = interface->minor;
415 
416 	mutex_lock(&open_disc_mutex);
417 	dev = usb_get_intfdata(interface);
418 	usb_set_intfdata(interface, NULL);
419 	mutex_unlock(&open_disc_mutex);
420 
421 	/* give back our minor */
422 	usb_deregister_dev(interface, &lcd_class);
423 
424 	/* decrement our usage count */
425 	kref_put(&dev->kref, lcd_delete);
426 
427 	dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
428 }
429 
430 static struct usb_driver lcd_driver = {
431 	.name =		"usblcd",
432 	.probe =	lcd_probe,
433 	.disconnect =	lcd_disconnect,
434 	.suspend =	lcd_suspend,
435 	.resume =	lcd_resume,
436 	.id_table =	id_table,
437 	.supports_autosuspend = 1,
438 };
439 
440 module_usb_driver(lcd_driver);
441 
442 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
443 MODULE_DESCRIPTION(DRIVER_VERSION);
444 MODULE_LICENSE("GPL");
445