USB: usblcd: Push down BKL into driver
[linux-2.6.git] / drivers / usb / misc / usblcd.c
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 <linux/mutex.h>
21 #include <asm/uaccess.h>
22 #include <linux/usb.h>
23
24 #define DRIVER_VERSION "USBLCD Driver Version 1.05"
25
26 #define USBLCD_MINOR            144
27
28 #define IOCTL_GET_HARD_VERSION  1
29 #define IOCTL_GET_DRV_VERSION   2
30
31
32 static 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 this device */
44         unsigned char *         bulk_in_buffer;         /* the buffer to receive data */
45         size_t                  bulk_in_size;           /* the size of the receive buffer */
46         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
47         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
48         struct kref             kref;
49         struct semaphore        limit_sem;              /* to stop writes at full throttle from
50                                                          * using up all RAM */
51         struct usb_anchor       submitted;              /* URBs to wait for before suspend */
52 };
53 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
54
55 #define USB_LCD_CONCURRENT_WRITES       5
56
57 static struct usb_driver lcd_driver;
58
59
60 static void lcd_delete(struct kref *kref)
61 {
62         struct usb_lcd *dev = to_lcd_dev(kref);
63
64         usb_put_dev(dev->udev);
65         kfree (dev->bulk_in_buffer);
66         kfree (dev);
67 }
68
69
70 static int lcd_open(struct inode *inode, struct file *file)
71 {
72         struct usb_lcd *dev;
73         struct usb_interface *interface;
74         int subminor, r;
75
76         subminor = iminor(inode);
77
78         interface = usb_find_interface(&lcd_driver, subminor);
79         if (!interface) {
80                 err ("USBLCD: %s - error, can't find device for minor %d",
81                      __func__, subminor);
82                 return -ENODEV;
83         }
84
85         mutex_lock(&open_disc_mutex);
86         dev = usb_get_intfdata(interface);
87         if (!dev) {
88                 mutex_unlock(&open_disc_mutex);
89                 return -ENODEV;
90         }
91
92         /* increment our usage count for the device */
93         kref_get(&dev->kref);
94         mutex_unlock(&open_disc_mutex);
95
96         /* grab a power reference */
97         r = usb_autopm_get_interface(interface);
98         if (r < 0) {
99                 kref_put(&dev->kref, lcd_delete);
100                 return r;
101         }
102
103         /* save our object in the file's private structure */
104         file->private_data = dev;
105
106         return 0;
107 }
108
109 static int lcd_release(struct inode *inode, struct file *file)
110 {
111         struct usb_lcd *dev;
112
113         dev = (struct usb_lcd *)file->private_data;
114         if (dev == NULL)
115                 return -ENODEV;
116
117         /* decrement the count on our device */
118         usb_autopm_put_interface(dev->interface);
119         kref_put(&dev->kref, lcd_delete);
120         return 0;
121 }
122
123 static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, loff_t *ppos)
124 {
125         struct usb_lcd *dev;
126         int retval = 0;
127         int bytes_read;
128
129         dev = (struct usb_lcd *)file->private_data;
130
131         /* do a blocking bulk read to get data from the device */
132         retval = usb_bulk_msg(dev->udev, 
133                               usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
134                               dev->bulk_in_buffer,
135                               min(dev->bulk_in_size, count),
136                               &bytes_read, 10000);
137
138         /* if the read was successful, copy the data to userspace */
139         if (!retval) {
140                 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
141                         retval = -EFAULT;
142                 else
143                         retval = bytes_read;
144         }
145
146         return retval;
147 }
148
149 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
150 {
151         struct usb_lcd *dev;
152         u16 bcdDevice;
153         char buf[30];
154
155         dev = (struct usb_lcd *)file->private_data;
156         if (dev == NULL)
157                 return -ENODEV;
158         
159         switch (cmd) {
160         case IOCTL_GET_HARD_VERSION:
161                 lock_kernel();
162                 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
163                 sprintf(buf,"%1d%1d.%1d%1d",
164                         (bcdDevice & 0xF000)>>12,
165                         (bcdDevice & 0xF00)>>8,
166                         (bcdDevice & 0xF0)>>4,
167                         (bcdDevice & 0xF));
168                 unlock_kernel();
169                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
170                         return -EFAULT;
171                 break;
172         case IOCTL_GET_DRV_VERSION:
173                 sprintf(buf,DRIVER_VERSION);
174                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
175                         return -EFAULT;
176                 break;
177         default:
178                 return -ENOTTY;
179                 break;
180         }
181
182         return 0;
183 }
184
185 static void lcd_write_bulk_callback(struct urb *urb)
186 {
187         struct usb_lcd *dev;
188         int status = urb->status;
189
190         dev = urb->context;
191
192         /* sync/async unlink faults aren't errors */
193         if (status &&
194             !(status == -ENOENT ||
195               status == -ECONNRESET ||
196               status == -ESHUTDOWN)) {
197                 dbg("USBLCD: %s - nonzero write bulk status received: %d",
198                     __func__, status);
199         }
200
201         /* free up our allocated buffer */
202         usb_buffer_free(urb->dev, urb->transfer_buffer_length,
203                         urb->transfer_buffer, urb->transfer_dma);
204         up(&dev->limit_sem);
205 }
206
207 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos)
208 {
209         struct usb_lcd *dev;
210         int retval = 0, r;
211         struct urb *urb = NULL;
212         char *buf = NULL;
213         
214         dev = (struct usb_lcd *)file->private_data;
215         
216         /* verify that we actually have some data to write */
217         if (count == 0)
218                 goto exit;
219
220         r = down_interruptible(&dev->limit_sem);
221         if (r < 0)
222                 return -EINTR;
223
224         /* create a urb, and a buffer for it, and copy the data to the urb */
225         urb = usb_alloc_urb(0, GFP_KERNEL);
226         if (!urb) {
227                 retval = -ENOMEM;
228                 goto err_no_buf;
229         }
230         
231         buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
232         if (!buf) {
233                 retval = -ENOMEM;
234                 goto error;
235         }
236         
237         if (copy_from_user(buf, user_buffer, count)) {
238                 retval = -EFAULT;
239                 goto error;
240         }
241         
242         /* initialize the urb properly */
243         usb_fill_bulk_urb(urb, dev->udev,
244                           usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
245                           buf, count, lcd_write_bulk_callback, dev);
246         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
247
248         usb_anchor_urb(urb, &dev->submitted);
249         
250         /* send the data out the bulk port */
251         retval = usb_submit_urb(urb, GFP_KERNEL);
252         if (retval) {
253                 err("USBLCD: %s - failed submitting write urb, error %d", __func__, retval);
254                 goto error_unanchor;
255         }
256         
257         /* release our reference to this urb, the USB core will eventually free it entirely */
258         usb_free_urb(urb);
259
260 exit:
261         return count;
262 error_unanchor:
263         usb_unanchor_urb(urb);
264 error:
265         usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
266         usb_free_urb(urb);
267 err_no_buf:
268         up(&dev->limit_sem);
269         return retval;
270 }
271
272 static const struct file_operations lcd_fops = {
273         .owner =        THIS_MODULE,
274         .read =         lcd_read,
275         .write =        lcd_write,
276         .open =         lcd_open,
277         .unlocked_ioctl = lcd_ioctl,
278         .release =      lcd_release,
279 };
280
281 /*
282  * usb class driver info in order to get a minor number from the usb core,
283  * and to have the device registered with the driver core
284  */
285 static struct usb_class_driver lcd_class = {
286         .name =         "lcd%d",
287         .fops =         &lcd_fops,
288         .minor_base =   USBLCD_MINOR,
289 };
290
291 static int lcd_probe(struct usb_interface *interface, const struct usb_device_id *id)
292 {
293         struct usb_lcd *dev = NULL;
294         struct usb_host_interface *iface_desc;
295         struct usb_endpoint_descriptor *endpoint;
296         size_t buffer_size;
297         int i;
298         int retval = -ENOMEM;
299
300         /* allocate memory for our device state and initialize it */
301         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
302         if (dev == NULL) {
303                 err("Out of memory");
304                 goto error;
305         }
306         kref_init(&dev->kref);
307         sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
308         init_usb_anchor(&dev->submitted);
309
310         dev->udev = usb_get_dev(interface_to_usbdev(interface));
311         dev->interface = interface;
312
313         if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
314                 warn(KERN_INFO "USBLCD model not supported.");
315                 return -ENODEV;
316         }
317         
318         /* set up the endpoint information */
319         /* use only the first bulk-in and bulk-out endpoints */
320         iface_desc = interface->cur_altsetting;
321         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
322                 endpoint = &iface_desc->endpoint[i].desc;
323
324                 if (!dev->bulk_in_endpointAddr &&
325                     usb_endpoint_is_bulk_in(endpoint)) {
326                         /* we found a bulk in endpoint */
327                         buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
328                         dev->bulk_in_size = buffer_size;
329                         dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
330                         dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
331                         if (!dev->bulk_in_buffer) {
332                                 err("Could not allocate bulk_in_buffer");
333                                 goto error;
334                         }
335                 }
336
337                 if (!dev->bulk_out_endpointAddr &&
338                     usb_endpoint_is_bulk_out(endpoint)) {
339                         /* we found a bulk out endpoint */
340                         dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
341                 }
342         }
343         if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
344                 err("Could not find both bulk-in and bulk-out endpoints");
345                 goto error;
346         }
347
348         /* save our data pointer in this interface device */
349         usb_set_intfdata(interface, dev);
350
351         /* we can register the device now, as it is ready */
352         retval = usb_register_dev(interface, &lcd_class);
353         if (retval) {
354                 /* something prevented us from registering this driver */
355                 err("Not able to get a minor for this device.");
356                 usb_set_intfdata(interface, NULL);
357                 goto error;
358         }
359
360         i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
361
362         info("USBLCD Version %1d%1d.%1d%1d found at address %d",
363                 (i & 0xF000)>>12,(i & 0xF00)>>8,(i & 0xF0)>>4,(i & 0xF),
364                 dev->udev->devnum);
365
366         /* let the user know what node this device is now attached to */
367         info("USB LCD device now attached to USBLCD-%d", interface->minor);
368         return 0;
369
370 error:
371         if (dev)
372                 kref_put(&dev->kref, lcd_delete);
373         return retval;
374 }
375
376 static void lcd_draw_down(struct usb_lcd *dev)
377 {
378         int time;
379
380         time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
381         if (!time)
382                 usb_kill_anchored_urbs(&dev->submitted);
383 }
384
385 static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
386 {
387         struct usb_lcd *dev = usb_get_intfdata(intf);
388
389         if (!dev)
390                 return 0;
391         lcd_draw_down(dev);
392         return 0;
393 }
394
395 static int lcd_resume (struct usb_interface *intf)
396 {
397         return 0;
398 }
399
400 static void lcd_disconnect(struct usb_interface *interface)
401 {
402         struct usb_lcd *dev;
403         int minor = interface->minor;
404
405         mutex_lock(&open_disc_mutex);
406         dev = usb_get_intfdata(interface);
407         usb_set_intfdata(interface, NULL);
408         mutex_unlock(&open_disc_mutex);
409
410         /* give back our minor */
411         usb_deregister_dev(interface, &lcd_class);
412  
413         /* decrement our usage count */
414         kref_put(&dev->kref, lcd_delete);
415
416         info("USB LCD #%d now disconnected", minor);
417 }
418
419 static struct usb_driver lcd_driver = {
420         .name =         "usblcd",
421         .probe =        lcd_probe,
422         .disconnect =   lcd_disconnect,
423         .suspend =      lcd_suspend,
424         .resume =       lcd_resume,
425         .id_table =     id_table,
426         .supports_autosuspend = 1,
427 };
428
429 static int __init usb_lcd_init(void)
430 {
431         int result;
432         
433         result = usb_register(&lcd_driver);
434         if (result)
435                 err("usb_register failed. Error number %d", result);
436
437         return result;
438 }
439
440
441 static void __exit usb_lcd_exit(void)
442 {
443         usb_deregister(&lcd_driver);
444 }
445
446 module_init(usb_lcd_init);
447 module_exit(usb_lcd_exit);
448
449 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
450 MODULE_DESCRIPTION(DRIVER_VERSION);
451 MODULE_LICENSE("GPL");