1 /*
2 * USB Skeleton driver - 2.0
3 *
4 * Copyright (C) 2001-2004 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, version 2.
9 *
10 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
11 * but has been rewritten to be easy to read and use, as no locks are now
12 * needed anymore.
13 *
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
21 #include <linux/kref.h>
22 #include <linux/smp_lock.h>
23 #include <linux/usb.h>
24 #include <asm/uaccess.h>
25
26
27 /* Define these values to match your devices */
28 #define USB_SKEL_VENDOR_ID 0xfff0
29 #define USB_SKEL_PRODUCT_ID 0xfff0
30
31 /* table of devices that work with this driver */
32 static struct usb_device_id skel_table [] = {
33 { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
34 { } /* Terminating entry */
35 };
36 MODULE_DEVICE_TABLE (usb, skel_table);
37
38
39 /* Get a minor range for your devices from the usb maintainer */
40 #define USB_SKEL_MINOR_BASE 192
41
42 /* Structure to hold all of our device specific stuff */
43 struct usb_skel {
44 struct usb_device * udev; /* the usb device for this device */
45 struct usb_interface * interface; /* the interface for this device */
46 unsigned char * bulk_in_buffer; /* the buffer to receive data */
47 size_t bulk_in_size; /* the size of the receive buffer */
48 __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
49 __u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
50 struct kref kref;
51 };
52 #define to_skel_dev(d) container_of(d, struct usb_skel, kref)
53
54 static struct usb_driver skel_driver;
55
56 static void skel_delete(struct kref *kref)
57 {
58 struct usb_skel *dev = to_skel_dev(kref);
59
60 usb_put_dev(dev->udev);
61 kfree (dev->bulk_in_buffer);
62 kfree (dev);
63 }
64
65 static int skel_open(struct inode *inode, struct file *file)
66 {
67 struct usb_skel *dev;
68 struct usb_interface *interface;
69 int subminor;
70 int retval = 0;
71
72 subminor = iminor(inode);
73
74 interface = usb_find_interface(&skel_driver, subminor);
75 if (!interface) {
76 err ("%s - error, can't find device for minor %d",
77 __FUNCTION__, subminor);
78 retval = -ENODEV;
79 goto exit;
80 }
81
82 dev = usb_get_intfdata(interface);
83 if (!dev) {
84 retval = -ENODEV;
85 goto exit;
86 }
87
88 /* increment our usage count for the device */
89 kref_get(&dev->kref);
90
91 /* save our object in the file's private structure */
92 file->private_data = dev;
93
94 exit:
95 return retval;
96 }
97
98 static int skel_release(struct inode *inode, struct file *file)
99 {
100 struct usb_skel *dev;
101
102 dev = (struct usb_skel *)file->private_data;
103 if (dev == NULL)
104 return -ENODEV;
105
106 /* decrement the count on our device */
107 kref_put(&dev->kref, skel_delete);
108 return 0;
109 }
110
111 static ssize_t skel_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
112 {
113 struct usb_skel *dev;
114 int retval = 0;
115 int actual_size;
116
117 dev = (struct usb_skel *)file->private_data;
118
119 /* do a blocking bulk read to get data from the device */
120 retval = usb_bulk_msg(dev->udev,
121 usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
122 dev->bulk_in_buffer,
123 min(dev->bulk_in_size, count),
124 &actual_size,
125 HZ*10);
126
127 /* if the read was successful, copy the data to userspace */
128 if (!retval) {
129 if (copy_to_user(buffer, dev->bulk_in_buffer, actual_size))
130 retval = -EFAULT;
131 else
132 retval = count;
133 }
134
135 return retval;
136 }
137
138 static void skel_write_bulk_callback(struct urb *urb)
139 {
140 /* sync/async unlink faults aren't errors */
141 if (urb->status &&
142 !(urb->status == -ENOENT ||
143 urb->status == -ECONNRESET ||
144 urb->status == -ESHUTDOWN)) {
145 dbg("%s - nonzero write bulk status received: %d",
146 __FUNCTION__, urb->status);
147 }
148
149 /* free up our allocated buffer */
150 usb_buffer_free(urb->dev, urb->transfer_buffer_length,
151 urb->transfer_buffer, urb->transfer_dma);
152 }
153
154 static ssize_t skel_write(struct file *file, const char __user *user_buffer, size_t count, loff_t *ppos)
155 {
156 struct usb_skel *dev;
157 int retval = 0;
158 struct urb *urb = NULL;
159 char *buf = NULL;
160
161 dev = (struct usb_skel *)file->private_data;
162
163 /* verify that we actually have some data to write */
164 if (count == 0)
165 goto exit;
166
167 /* create a urb, and a buffer for it, and copy the data to the urb */
168 urb = usb_alloc_urb(0, GFP_KERNEL);
169 if (!urb) {
170 retval = -ENOMEM;
171 goto error;
172 }
173
174 buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
175 if (!buf) {
176 retval = -ENOMEM;
177 goto error;
178 }
179 if (copy_from_user(buf, user_buffer, count)) {
180 retval = -EFAULT;
181 goto error;
182 }
183
184 /* initialize the urb properly */
185 usb_fill_bulk_urb(urb, dev->udev,
186 usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
187 buf, count, skel_write_bulk_callback, dev);
188 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
189
190 /* send the data out the bulk port */
191 retval = usb_submit_urb(urb, GFP_KERNEL);
192 if (retval) {
193 err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
194 goto error;
195 }
196
197 /* release our reference to this urb, the USB core will eventually free it entirely */
198 usb_free_urb(urb);
199
200 exit:
201 return count;
202
203 error:
204 usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
205 usb_free_urb(urb);
206 kfree(buf);
207 return retval;
208 }
209
210 static struct file_operations skel_fops = {
211 .owner = THIS_MODULE,
212 .read = skel_read,
213 .write = skel_write,
214 .open = skel_open,
215 .release = skel_release,
216 };
217
218 /*
219 * usb class driver info in order to get a minor number from the usb core,
220 * and to have the device registered with devfs and the driver core
221 */
222 static struct usb_class_driver skel_class = {
223 .name = "usb/skel%d",
224 .fops = &skel_fops,
225 .minor_base = USB_SKEL_MINOR_BASE,
226 };
227
228 static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
229 {
230 struct usb_skel *dev = NULL;
231 struct usb_host_interface *iface_desc;
232 struct usb_endpoint_descriptor *endpoint;
233 size_t buffer_size;
234 int i;
235 int retval = -ENOMEM;
236
237 /* allocate memory for our device state and initialize it */
238 dev = kmalloc(sizeof(struct usb_skel), GFP_KERNEL);
239 if (dev == NULL) {
240 err("Out of memory");
241 goto error;
242 }
243 memset(dev, 0x00, sizeof (*dev));
244 kref_init(&dev->kref);
245
246 dev->udev = usb_get_dev(interface_to_usbdev(interface));
247 dev->interface = interface;
248
249 /* set up the endpoint information */
250 /* use only the first bulk-in and bulk-out endpoints */
251 iface_desc = interface->cur_altsetting;
252 for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
253 endpoint = &iface_desc->endpoint[i].desc;
254
255 if (!dev->bulk_in_endpointAddr &&
256 (endpoint->bEndpointAddress & USB_DIR_IN) &&
257 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
258 == USB_ENDPOINT_XFER_BULK)) {
259 /* we found a bulk in endpoint */
260 buffer_size = endpoint->wMaxPacketSize;
261 dev->bulk_in_size = buffer_size;
262 dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
263 dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
264 if (!dev->bulk_in_buffer) {
265 err("Could not allocate bulk_in_buffer");
266 goto error;
267 }
268 }
269
270 if (!dev->bulk_out_endpointAddr &&
271 !(endpoint->bEndpointAddress & USB_DIR_IN) &&
272 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
273 == USB_ENDPOINT_XFER_BULK)) {
274 /* we found a bulk out endpoint */
275 dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
276 }
277 }
278 if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
279 err("Could not find both bulk-in and bulk-out endpoints");
280 goto error;
281 }
282
283 /* save our data pointer in this interface device */
284 usb_set_intfdata(interface, dev);
285
286 /* we can register the device now, as it is ready */
287 retval = usb_register_dev(interface, &skel_class);
288 if (retval) {
289 /* something prevented us from registering this driver */
290 err("Not able to get a minor for this device.");
291 usb_set_intfdata(interface, NULL);
292 goto error;
293 }
294
295 /* let the user know what node this device is now attached to */
296 info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
297 return 0;
298
299 error:
300 if (dev)
301 kref_put(&dev->kref, skel_delete);
302 return retval;
303 }
304
305 static void skel_disconnect(struct usb_interface *interface)
306 {
307 struct usb_skel *dev;
308 int minor = interface->minor;
309
310 /* prevent skel_open() from racing skel_disconnect() */
311 lock_kernel();
312
313 dev = usb_get_intfdata(interface);
314 usb_set_intfdata(interface, NULL);
315
316 /* give back our minor */
317 usb_deregister_dev(interface, &skel_class);
318
319 unlock_kernel();
320
321 /* decrement our usage count */
322 kref_put(&dev->kref, skel_delete);
323
324 info("USB Skeleton #%d now disconnected", minor);
325 }
326
327 static struct usb_driver skel_driver = {
328 .name = "skeleton",
329 .id_table = skel_table,
330 .probe = skel_probe,
331 .disconnect = skel_disconnect,
332 };
333
334 static int __init usb_skel_init(void)
335 {
336 int result;
337
338 /* register this driver with the USB subsystem */
339 result = usb_register(&skel_driver);
340 if (result)
341 err("usb_register failed. Error number %d", result);
342
343 return result;
344 }
345
346 static void __exit usb_skel_exit(void)
347 {
348 /* deregister this driver with the USB subsystem */
349 usb_deregister(&skel_driver);
350 }
351
352 module_init (usb_skel_init);
353 module_exit (usb_skel_exit);
354
355 MODULE_LICENSE("GPL");
356
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