File: /usr/src/linux/drivers/usb/usb-skeleton.c
1 /*
2 * USB Skeleton driver - 0.4
3 *
4 * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of
9 * the License, or (at your option) any later version.
10 *
11 *
12 * This driver is to be used as a skeleton driver to be able to create a
13 * USB driver quickly. The design of it is based on the usb-serial and
14 * dc2xx drivers.
15 *
16 * Thanks to Oliver Neukum and David Brownell for their help in debugging
17 * this driver.
18 *
19 * TODO:
20 * - fix urb->status race condition in write sequence
21 * - move minor_table to a dynamic list.
22 *
23 * History:
24 *
25 * 2001_08_21 - 0.4 - more small bug fixes.
26 * 2001_05_29 - 0.3 - more bug fixes based on review from linux-usb-devel
27 * 2001_05_24 - 0.2 - bug fixes based on review from linux-usb-devel people
28 * 2001_05_01 - 0.1 - first version
29 *
30 */
31
32 #include <linux/config.h>
33 #include <linux/kernel.h>
34 #include <linux/sched.h>
35 #include <linux/signal.h>
36 #include <linux/errno.h>
37 #include <linux/poll.h>
38 #include <linux/init.h>
39 #include <linux/slab.h>
40 #include <linux/fcntl.h>
41 #include <linux/module.h>
42 #include <linux/spinlock.h>
43 #include <linux/list.h>
44 #include <linux/smp_lock.h>
45 #include <linux/devfs_fs_kernel.h>
46 #include <linux/usb.h>
47
48 #ifdef CONFIG_USB_DEBUG
49 static int debug = 1;
50 #else
51 static int debug;
52 #endif
53
54 /* Use our own dbg macro */
55 #undef dbg
56 #define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg); } while (0)
57
58
59 /* Version Information */
60 #define DRIVER_VERSION "v0.4"
61 #define DRIVER_AUTHOR "Greg Kroah-Hartman, greg@kroah.com"
62 #define DRIVER_DESC "USB Skeleton Driver"
63
64 /* Module paramaters */
65 MODULE_PARM(debug, "i");
66 MODULE_PARM_DESC(debug, "Debug enabled or not");
67
68
69 /* Define these values to match your device */
70 #define USB_SKEL_VENDOR_ID 0xfff0
71 #define USB_SKEL_PRODUCT_ID 0xfff0
72
73 /* table of devices that work with this driver */
74 static struct usb_device_id skel_table [] = {
75 { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
76 { } /* Terminating entry */
77 };
78
79 MODULE_DEVICE_TABLE (usb, skel_table);
80
81
82
83 /* Get a minor range for your devices from the usb maintainer */
84 #define USB_SKEL_MINOR_BASE 200
85
86 /* we can have up to this number of device plugged in at once */
87 #define MAX_DEVICES 16
88
89 /* Structure to hold all of our device specific stuff */
90 struct usb_skel {
91 struct usb_device * udev; /* save off the usb device pointer */
92 struct usb_interface * interface; /* the interface for this device */
93 devfs_handle_t devfs; /* devfs device node */
94 unsigned char minor; /* the starting minor number for this device */
95 unsigned char num_ports; /* the number of ports this device has */
96 char num_interrupt_in; /* number of interrupt in endpoints we have */
97 char num_bulk_in; /* number of bulk in endpoints we have */
98 char num_bulk_out; /* number of bulk out endpoints we have */
99
100 unsigned char * bulk_in_buffer; /* the buffer to receive data */
101 int bulk_in_size; /* the size of the receive buffer */
102 __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
103
104 unsigned char * bulk_out_buffer; /* the buffer to send data */
105 int bulk_out_size; /* the size of the send buffer */
106 struct urb * write_urb; /* the urb used to send data */
107 __u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
108
109 struct tq_struct tqueue; /* task queue for line discipline waking up */
110 int open_count; /* number of times this port has been opened */
111 struct semaphore sem; /* locks this structure */
112 };
113
114
115 /* the global usb devfs handle */
116 extern devfs_handle_t usb_devfs_handle;
117
118
119 /* local function prototypes */
120 static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos);
121 static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos);
122 static int skel_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
123 static int skel_open (struct inode *inode, struct file *file);
124 static int skel_release (struct inode *inode, struct file *file);
125
126 static void * skel_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id);
127 static void skel_disconnect (struct usb_device *dev, void *ptr);
128
129 static void skel_write_bulk_callback (struct urb *urb);
130
131
132 /* array of pointers to our devices that are currently connected */
133 static struct usb_skel *minor_table[MAX_DEVICES];
134
135 /* lock to protect the minor_table structure */
136 static DECLARE_MUTEX (minor_table_mutex);
137
138 /* file operations needed when we register this driver */
139 static struct file_operations skel_fops = {
140 owner: THIS_MODULE,
141 read: skel_read,
142 write: skel_write,
143 ioctl: skel_ioctl,
144 open: skel_open,
145 release: skel_release,
146 };
147
148
149 /* usb specific object needed to register this driver with the usb subsystem */
150 static struct usb_driver skel_driver = {
151 name: "skeleton",
152 probe: skel_probe,
153 disconnect: skel_disconnect,
154 fops: &skel_fops,
155 minor: USB_SKEL_MINOR_BASE,
156 id_table: skel_table,
157 };
158
159
160
161
162
163 /**
164 * usb_skel_debug_data
165 */
166 static inline void usb_skel_debug_data (const char *function, int size, const unsigned char *data)
167 {
168 int i;
169
170 if (!debug)
171 return;
172
173 printk (KERN_DEBUG __FILE__": %s - length = %d, data = ",
174 function, size);
175 for (i = 0; i < size; ++i) {
176 printk ("%.2x ", data[i]);
177 }
178 printk ("\n");
179 }
180
181
182 /**
183 * skel_delete
184 */
185 static inline void skel_delete (struct usb_skel *dev)
186 {
187 minor_table[dev->minor] = NULL;
188 if (dev->bulk_in_buffer != NULL)
189 kfree (dev->bulk_in_buffer);
190 if (dev->bulk_out_buffer != NULL)
191 kfree (dev->bulk_out_buffer);
192 if (dev->write_urb != NULL)
193 usb_free_urb (dev->write_urb);
194 kfree (dev);
195 }
196
197
198 /**
199 * skel_open
200 */
201 static int skel_open (struct inode *inode, struct file *file)
202 {
203 struct usb_skel *dev = NULL;
204 int subminor;
205 int retval = 0;
206
207 dbg(__FUNCTION__);
208
209 subminor = MINOR (inode->i_rdev) - USB_SKEL_MINOR_BASE;
210 if ((subminor < 0) ||
211 (subminor >= MAX_DEVICES)) {
212 return -ENODEV;
213 }
214
215 /* increment our usage count for the module */
216 MOD_INC_USE_COUNT;
217
218 /* lock our minor table and get our local data for this minor */
219 down (&minor_table_mutex);
220 dev = minor_table[subminor];
221 if (dev == NULL) {
222 up (&minor_table_mutex);
223 MOD_DEC_USE_COUNT;
224 return -ENODEV;
225 }
226
227 /* lock this device */
228 down (&dev->sem);
229
230 /* unlock the minor table */
231 up (&minor_table_mutex);
232
233 /* increment our usage count for the driver */
234 ++dev->open_count;
235
236 /* save our object in the file's private structure */
237 file->private_data = dev;
238
239 /* unlock this device */
240 up (&dev->sem);
241
242 return retval;
243 }
244
245
246 /**
247 * skel_release
248 */
249 static int skel_release (struct inode *inode, struct file *file)
250 {
251 struct usb_skel *dev;
252 int retval = 0;
253
254 dev = (struct usb_skel *)file->private_data;
255 if (dev == NULL) {
256 dbg (__FUNCTION__ " - object is NULL");
257 return -ENODEV;
258 }
259
260 dbg(__FUNCTION__ " - minor %d", dev->minor);
261
262 /* lock our minor table */
263 down (&minor_table_mutex);
264
265 /* lock our device */
266 down (&dev->sem);
267
268 if (dev->open_count <= 0) {
269 dbg (__FUNCTION__ " - device not opened");
270 retval = -ENODEV;
271 goto exit_not_opened;
272 }
273
274 if (dev->udev == NULL) {
275 /* the device was unplugged before the file was released */
276 up (&dev->sem);
277 skel_delete (dev);
278 MOD_DEC_USE_COUNT;
279 up (&minor_table_mutex);
280 return 0;
281 }
282
283 /* decrement our usage count for the device */
284 --dev->open_count;
285 if (dev->open_count <= 0) {
286 /* shutdown any bulk writes that might be going on */
287 usb_unlink_urb (dev->write_urb);
288 dev->open_count = 0;
289 }
290
291 /* decrement our usage count for the module */
292 MOD_DEC_USE_COUNT;
293
294 exit_not_opened:
295 up (&dev->sem);
296 up (&minor_table_mutex);
297
298 return retval;
299 }
300
301
302 /**
303 * skel_read
304 */
305 static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
306 {
307 struct usb_skel *dev;
308 int retval = 0;
309
310 dev = (struct usb_skel *)file->private_data;
311
312 dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count);
313
314 /* lock this object */
315 down (&dev->sem);
316
317 /* verify that the device wasn't unplugged */
318 if (dev->udev == NULL) {
319 up (&dev->sem);
320 return -ENODEV;
321 }
322
323 /* do an immediate bulk read to get data from the device */
324 retval = usb_bulk_msg (dev->udev,
325 usb_rcvbulkpipe (dev->udev,
326 dev->bulk_in_endpointAddr),
327 dev->bulk_in_buffer, dev->bulk_in_size,
328 &count, HZ*10);
329
330 /* if the read was successful, copy the data to userspace */
331 if (!retval) {
332 if (copy_to_user (buffer, dev->bulk_in_buffer, count))
333 retval = -EFAULT;
334 else
335 retval = count;
336 }
337
338 /* unlock the device */
339 up (&dev->sem);
340 return retval;
341 }
342
343
344 /**
345 * skel_write
346 */
347 static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
348 {
349 struct usb_skel *dev;
350 ssize_t bytes_written = 0;
351 int retval = 0;
352
353 dev = (struct usb_skel *)file->private_data;
354
355 dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count);
356
357 /* lock this object */
358 down (&dev->sem);
359
360 /* verify that the device wasn't unplugged */
361 if (dev->udev == NULL) {
362 retval = -ENODEV;
363 goto exit;
364 }
365
366 /* verify that we actually have some data to write */
367 if (count == 0) {
368 dbg(__FUNCTION__ " - write request of 0 bytes");
369 goto exit;
370 }
371
372 /* see if we are already in the middle of a write */
373 if (dev->write_urb->status == -EINPROGRESS) {
374 dbg (__FUNCTION__ " - already writing");
375 goto exit;
376 }
377
378 /* we can only write as much as 1 urb will hold */
379 bytes_written = (count > dev->bulk_out_size) ?
380 dev->bulk_out_size : count;
381
382 /* copy the data from userspace into our urb */
383 if (copy_from_user(dev->write_urb->transfer_buffer, buffer,
384 bytes_written)) {
385 retval = -EFAULT;
386 goto exit;
387 }
388
389 usb_skel_debug_data (__FUNCTION__, bytes_written,
390 dev->write_urb->transfer_buffer);
391
392 /* set up our urb */
393 FILL_BULK_URB(dev->write_urb, dev->udev,
394 usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
395 dev->write_urb->transfer_buffer, bytes_written,
396 skel_write_bulk_callback, dev);
397
398 /* send the data out the bulk port */
399 retval = usb_submit_urb(dev->write_urb);
400 if (retval) {
401 err(__FUNCTION__ " - failed submitting write urb, error %d",
402 retval);
403 } else {
404 retval = bytes_written;
405 }
406
407 exit:
408 /* unlock the device */
409 up (&dev->sem);
410
411 return retval;
412 }
413
414
415 /**
416 * skel_ioctl
417 */
418 static int skel_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
419 {
420 struct usb_skel *dev;
421
422 dev = (struct usb_skel *)file->private_data;
423
424 /* lock this object */
425 down (&dev->sem);
426
427 /* verify that the device wasn't unplugged */
428 if (dev->udev == NULL) {
429 up (&dev->sem);
430 return -ENODEV;
431 }
432
433 dbg(__FUNCTION__ " - minor %d, cmd 0x%.4x, arg %ld",
434 dev->minor, cmd, arg);
435
436
437 /* fill in your device specific stuff here */
438
439 /* unlock the device */
440 up (&dev->sem);
441
442 /* return that we did not understand this ioctl call */
443 return -ENOTTY;
444 }
445
446
447 /**
448 * skel_write_bulk_callback
449 */
450 static void skel_write_bulk_callback (struct urb *urb)
451 {
452 struct usb_skel *dev = (struct usb_skel *)urb->context;
453
454 dbg(__FUNCTION__ " - minor %d", dev->minor);
455
456 if ((urb->status != -ENOENT) &&
457 (urb->status != -ECONNRESET)) {
458 dbg(__FUNCTION__ " - nonzero write bulk status received: %d",
459 urb->status);
460 return;
461 }
462
463 return;
464 }
465
466
467 /**
468 * skel_probe
469 *
470 * Called by the usb core when a new device is connected that it thinks
471 * this driver might be interested in.
472 */
473 static void * skel_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id)
474 {
475 struct usb_skel *dev = NULL;
476 struct usb_interface *interface;
477 struct usb_interface_descriptor *iface_desc;
478 struct usb_endpoint_descriptor *endpoint;
479 int minor;
480 int buffer_size;
481 int i;
482 char name[10];
483
484
485 /* See if the device offered us matches what we can accept */
486 if ((udev->descriptor.idVendor != USB_SKEL_VENDOR_ID) ||
487 (udev->descriptor.idProduct != USB_SKEL_PRODUCT_ID)) {
488 return NULL;
489 }
490
491 /* select a "subminor" number (part of a minor number) */
492 down (&minor_table_mutex);
493 for (minor = 0; minor < MAX_DEVICES; ++minor) {
494 if (minor_table[minor] == NULL)
495 break;
496 }
497 if (minor >= MAX_DEVICES) {
498 info ("Too many devices plugged in, can not handle this device.");
499 goto exit;
500 }
501
502 /* allocate memory for our device state and intialize it */
503 dev = kmalloc (sizeof(struct usb_skel), GFP_KERNEL);
504 if (dev == NULL) {
505 err ("Out of memory");
506 goto exit;
507 }
508 minor_table[minor] = dev;
509
510 interface = &udev->actconfig->interface[ifnum];
511
512 init_MUTEX (&dev->sem);
513 dev->udev = udev;
514 dev->interface = interface;
515 dev->minor = minor;
516
517 /* set up the endpoint information */
518 /* check out the endpoints */
519 iface_desc = &interface->altsetting[0];
520 for (i = 0; i < iface_desc->bNumEndpoints; ++i) {
521 endpoint = &iface_desc->endpoint[i];
522
523 if ((endpoint->bEndpointAddress & 0x80) &&
524 ((endpoint->bmAttributes & 3) == 0x02)) {
525 /* we found a bulk in endpoint */
526 buffer_size = endpoint->wMaxPacketSize;
527 dev->bulk_in_size = buffer_size;
528 dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
529 dev->bulk_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
530 if (!dev->bulk_in_buffer) {
531 err("Couldn't allocate bulk_in_buffer");
532 goto error;
533 }
534 }
535
536 if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
537 ((endpoint->bmAttributes & 3) == 0x02)) {
538 /* we found a bulk out endpoint */
539 dev->write_urb = usb_alloc_urb(0);
540 if (!dev->write_urb) {
541 err("No free urbs available");
542 goto error;
543 }
544 buffer_size = endpoint->wMaxPacketSize;
545 dev->bulk_out_size = buffer_size;
546 dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
547 dev->bulk_out_buffer = kmalloc (buffer_size, GFP_KERNEL);
548 if (!dev->bulk_out_buffer) {
549 err("Couldn't allocate bulk_out_buffer");
550 goto error;
551 }
552 FILL_BULK_URB(dev->write_urb, udev,
553 usb_sndbulkpipe(udev,
554 endpoint->bEndpointAddress),
555 dev->bulk_out_buffer, buffer_size,
556 skel_write_bulk_callback, dev);
557 }
558 }
559
560 /* initialize the devfs node for this device and register it */
561 sprintf(name, "skel%d", dev->minor);
562
563 dev->devfs = devfs_register (usb_devfs_handle, name,
564 DEVFS_FL_DEFAULT, USB_MAJOR,
565 USB_SKEL_MINOR_BASE + dev->minor,
566 S_IFCHR | S_IRUSR | S_IWUSR |
567 S_IRGRP | S_IWGRP | S_IROTH,
568 &skel_fops, NULL);
569
570 /* let the user know what node this device is now attached to */
571 info ("USB Skeleton device now attached to USBSkel%d", dev->minor);
572 goto exit;
573
574 error:
575 skel_delete (dev);
576 dev = NULL;
577
578 exit:
579 up (&minor_table_mutex);
580 return dev;
581 }
582
583
584 /**
585 * skel_disconnect
586 *
587 * Called by the usb core when the device is removed from the system.
588 */
589 static void skel_disconnect(struct usb_device *udev, void *ptr)
590 {
591 struct usb_skel *dev;
592 int minor;
593
594 dev = (struct usb_skel *)ptr;
595
596 down (&minor_table_mutex);
597 down (&dev->sem);
598
599 minor = dev->minor;
600
601 /* if the device is not opened, then we clean up right now */
602 if (!dev->open_count) {
603 skel_delete (dev);
604 } else {
605 dev->udev = NULL;
606 up (&dev->sem);
607 }
608
609 /* remove our devfs node */
610 devfs_unregister(dev->devfs);
611
612 info("USB Skeleton #%d now disconnected", minor);
613 up (&minor_table_mutex);
614 }
615
616
617
618 /**
619 * usb_skel_init
620 */
621 static int __init usb_skel_init(void)
622 {
623 int result;
624
625 /* register this driver with the USB subsystem */
626 result = usb_register(&skel_driver);
627 if (result < 0) {
628 err("usb_register failed for the "__FILE__" driver. Error number %d",
629 result);
630 return -1;
631 }
632
633 info(DRIVER_DESC " " DRIVER_VERSION);
634 return 0;
635 }
636
637
638 /**
639 * usb_skel_exit
640 */
641 static void __exit usb_skel_exit(void)
642 {
643 /* deregister this driver with the USB subsystem */
644 usb_deregister(&skel_driver);
645 }
646
647
648 module_init (usb_skel_init);
649 module_exit (usb_skel_exit);
650
651 MODULE_AUTHOR(DRIVER_AUTHOR);
652 MODULE_DESCRIPTION(DRIVER_DESC);
653 MODULE_LICENSE("GPL");
654
655