Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * USB Serial Converter Generic functions
  3  *
  4  * Copyright (C) 1999 - 2002 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 version
  8  *      2 as published by the Free Software Foundation.
  9  *
 10  */
 11 
 12 #include <linux/kernel.h>
 13 #include <linux/errno.h>
 14 #include <linux/slab.h>
 15 #include <linux/tty.h>
 16 #include <linux/tty_flip.h>
 17 #include <linux/module.h>
 18 #include <linux/moduleparam.h>
 19 #include <linux/usb.h>
 20 #include <linux/usb/serial.h>
 21 #include <asm/uaccess.h>
 22 
 23 
 24 static int debug;
 25 
 26 #ifdef CONFIG_USB_SERIAL_GENERIC
 27 
 28 static int generic_probe(struct usb_interface *interface,
 29                          const struct usb_device_id *id);
 30 
 31 static __u16 vendor  = 0x05f9;
 32 static __u16 product = 0xffff;
 33 
 34 module_param(vendor, ushort, 0);
 35 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
 36 
 37 module_param(product, ushort, 0);
 38 MODULE_PARM_DESC(product, "User specified USB idProduct");
 39 
 40 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
 41 
 42 /* we want to look at all devices, as the vendor/product id can change
 43  * depending on the command line argument */
 44 static struct usb_device_id generic_serial_ids[] = {
 45         {.driver_info = 42},
 46         {}
 47 };
 48 
 49 static struct usb_driver generic_driver = {
 50         .name =         "usbserial_generic",
 51         .probe =        generic_probe,
 52         .disconnect =   usb_serial_disconnect,
 53         .id_table =     generic_serial_ids,
 54         .no_dynamic_id =        1,
 55 };
 56 
 57 /* All of the device info needed for the Generic Serial Converter */
 58 struct usb_serial_driver usb_serial_generic_device = {
 59         .driver = {
 60                 .owner =        THIS_MODULE,
 61                 .name =         "generic",
 62         },
 63         .id_table =             generic_device_ids,
 64         .usb_driver =           &generic_driver,
 65         .num_interrupt_in =     NUM_DONT_CARE,
 66         .num_bulk_in =          NUM_DONT_CARE,
 67         .num_bulk_out =         NUM_DONT_CARE,
 68         .num_ports =            1,
 69         .shutdown =             usb_serial_generic_shutdown,
 70         .throttle =             usb_serial_generic_throttle,
 71         .unthrottle =           usb_serial_generic_unthrottle,
 72         .resume =               usb_serial_generic_resume,
 73 };
 74 
 75 static int generic_probe(struct usb_interface *interface,
 76                                const struct usb_device_id *id)
 77 {
 78         const struct usb_device_id *id_pattern;
 79 
 80         id_pattern = usb_match_id(interface, generic_device_ids);
 81         if (id_pattern != NULL)
 82                 return usb_serial_probe(interface, id);
 83         return -ENODEV;
 84 }
 85 #endif
 86 
 87 int usb_serial_generic_register (int _debug)
 88 {
 89         int retval = 0;
 90 
 91         debug = _debug;
 92 #ifdef CONFIG_USB_SERIAL_GENERIC
 93         generic_device_ids[0].idVendor = vendor;
 94         generic_device_ids[0].idProduct = product;
 95         generic_device_ids[0].match_flags = USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
 96 
 97         /* register our generic driver with ourselves */
 98         retval = usb_serial_register (&usb_serial_generic_device);
 99         if (retval)
100                 goto exit;
101         retval = usb_register(&generic_driver);
102         if (retval)
103                 usb_serial_deregister(&usb_serial_generic_device);
104 exit:
105 #endif
106         return retval;
107 }
108 
109 void usb_serial_generic_deregister (void)
110 {
111 #ifdef CONFIG_USB_SERIAL_GENERIC
112         /* remove our generic driver */
113         usb_deregister(&generic_driver);
114         usb_serial_deregister (&usb_serial_generic_device);
115 #endif
116 }
117 
118 int usb_serial_generic_open (struct usb_serial_port *port, struct file *filp)
119 {
120         struct usb_serial *serial = port->serial;
121         int result = 0;
122         unsigned long flags;
123 
124         dbg("%s - port %d", __FUNCTION__, port->number);
125 
126         /* force low_latency on so that our tty_push actually forces the data through, 
127            otherwise it is scheduled, and with high data rates (like with OHCI) data
128            can get lost. */
129         if (port->tty)
130                 port->tty->low_latency = 1;
131 
132         /* clear the throttle flags */
133         spin_lock_irqsave(&port->lock, flags);
134         port->throttled = 0;
135         port->throttle_req = 0;
136         spin_unlock_irqrestore(&port->lock, flags);
137 
138         /* if we have a bulk endpoint, start reading from it */
139         if (serial->num_bulk_in) {
140                 /* Start reading from the device */
141                 usb_fill_bulk_urb (port->read_urb, serial->dev,
142                                    usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
143                                    port->read_urb->transfer_buffer,
144                                    port->read_urb->transfer_buffer_length,
145                                    ((serial->type->read_bulk_callback) ?
146                                      serial->type->read_bulk_callback :
147                                      usb_serial_generic_read_bulk_callback),
148                                    port);
149                 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
150                 if (result)
151                         dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
152         }
153 
154         return result;
155 }
156 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
157 
158 static void generic_cleanup (struct usb_serial_port *port)
159 {
160         struct usb_serial *serial = port->serial;
161 
162         dbg("%s - port %d", __FUNCTION__, port->number);
163 
164         if (serial->dev) {
165                 /* shutdown any bulk reads that might be going on */
166                 if (serial->num_bulk_out)
167                         usb_kill_urb(port->write_urb);
168                 if (serial->num_bulk_in)
169                         usb_kill_urb(port->read_urb);
170         }
171 }
172 
173 int usb_serial_generic_resume(struct usb_serial *serial)
174 {
175         struct usb_serial_port *port;
176         int i, c = 0, r;
177 
178 #ifdef CONFIG_PM
179         /*
180          * If this is an autoresume, don't submit URBs.
181          * They will be submitted in the open function instead.
182          */
183         if (serial->dev->auto_pm)
184                 return 0;
185 #endif
186         for (i = 0; i < serial->num_ports; i++) {
187                 port = serial->port[i];
188                 if (port->open_count && port->read_urb) {
189                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
190                         if (r < 0)
191                                 c++;
192                 }
193         }
194 
195         return c ? -EIO : 0;
196 }
197 
198 void usb_serial_generic_close (struct usb_serial_port *port, struct file * filp)
199 {
200         dbg("%s - port %d", __FUNCTION__, port->number);
201         generic_cleanup (port);
202 }
203 
204 int usb_serial_generic_write(struct usb_serial_port *port, const unsigned char *buf, int count)
205 {
206         struct usb_serial *serial = port->serial;
207         int result;
208         unsigned char *data;
209 
210         dbg("%s - port %d", __FUNCTION__, port->number);
211 
212         if (count == 0) {
213                 dbg("%s - write request of 0 bytes", __FUNCTION__);
214                 return (0);
215         }
216 
217         /* only do something if we have a bulk out endpoint */
218         if (serial->num_bulk_out) {
219                 unsigned long flags;
220                 spin_lock_irqsave(&port->lock, flags);
221                 if (port->write_urb_busy) {
222                         spin_unlock_irqrestore(&port->lock, flags);
223                         dbg("%s - already writing", __FUNCTION__);
224                         return 0;
225                 }
226                 port->write_urb_busy = 1;
227                 spin_unlock_irqrestore(&port->lock, flags);
228 
229                 count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
230 
231                 memcpy (port->write_urb->transfer_buffer, buf, count);
232                 data = port->write_urb->transfer_buffer;
233                 usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, data);
234 
235                 /* set up our urb */
236                 usb_fill_bulk_urb (port->write_urb, serial->dev,
237                                    usb_sndbulkpipe (serial->dev,
238                                                     port->bulk_out_endpointAddress),
239                                    port->write_urb->transfer_buffer, count,
240                                    ((serial->type->write_bulk_callback) ? 
241                                      serial->type->write_bulk_callback :
242                                      usb_serial_generic_write_bulk_callback), port);
243 
244                 /* send the data out the bulk port */
245                 port->write_urb_busy = 1;
246                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
247                 if (result) {
248                         dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
249                         /* don't have to grab the lock here, as we will retry if != 0 */
250                         port->write_urb_busy = 0;
251                 } else
252                         result = count;
253 
254                 return result;
255         }
256 
257         /* no bulk out, so return 0 bytes written */
258         return 0;
259 }
260 
261 int usb_serial_generic_write_room (struct usb_serial_port *port)
262 {
263         struct usb_serial *serial = port->serial;
264         int room = 0;
265 
266         dbg("%s - port %d", __FUNCTION__, port->number);
267 
268         if (serial->num_bulk_out) {
269                 if (!(port->write_urb_busy))
270                         room = port->bulk_out_size;
271         }
272 
273         dbg("%s - returns %d", __FUNCTION__, room);
274         return (room);
275 }
276 
277 int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
278 {
279         struct usb_serial *serial = port->serial;
280         int chars = 0;
281 
282         dbg("%s - port %d", __FUNCTION__, port->number);
283 
284         if (serial->num_bulk_out) {
285                 if (port->write_urb_busy)
286                         chars = port->write_urb->transfer_buffer_length;
287         }
288 
289         dbg("%s - returns %d", __FUNCTION__, chars);
290         return (chars);
291 }
292 
293 
294 static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
295 {
296         struct urb *urb = port->read_urb;
297         struct usb_serial *serial = port->serial;
298         int result;
299 
300         /* Continue reading from device */
301         usb_fill_bulk_urb (urb, serial->dev,
302                            usb_rcvbulkpipe (serial->dev,
303                                             port->bulk_in_endpointAddress),
304                            urb->transfer_buffer,
305                            urb->transfer_buffer_length,
306                            ((serial->type->read_bulk_callback) ? 
307                              serial->type->read_bulk_callback : 
308                              usb_serial_generic_read_bulk_callback), port);
309         result = usb_submit_urb(urb, mem_flags);
310         if (result)
311                 dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
312 }
313 
314 /* Push data to tty layer and resubmit the bulk read URB */
315 static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
316 {
317         struct urb *urb = port->read_urb;
318         struct tty_struct *tty = port->tty;
319         int room;
320 
321         /* Push data to tty */
322         if (tty && urb->actual_length) {
323                 room = tty_buffer_request_room(tty, urb->actual_length);
324                 if (room) {
325                         tty_insert_flip_string(tty, urb->transfer_buffer, room);
326                         tty_flip_buffer_push(tty);
327                 }
328         }
329 
330         resubmit_read_urb(port, GFP_ATOMIC);
331 }
332 
333 void usb_serial_generic_read_bulk_callback (struct urb *urb)
334 {
335         struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
336         unsigned char *data = urb->transfer_buffer;
337         int status = urb->status;
338         unsigned long flags;
339 
340         dbg("%s - port %d", __FUNCTION__, port->number);
341 
342         if (unlikely(status != 0)) {
343                 dbg("%s - nonzero read bulk status received: %d",
344                     __FUNCTION__, status);
345                 return;
346         }
347 
348         usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
349 
350         /* Throttle the device if requested by tty */
351         spin_lock_irqsave(&port->lock, flags);
352         if (!(port->throttled = port->throttle_req)) {
353                 spin_unlock_irqrestore(&port->lock, flags);
354                 flush_and_resubmit_read_urb(port);
355         } else {
356                 spin_unlock_irqrestore(&port->lock, flags);
357         }
358 }
359 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
360 
361 void usb_serial_generic_write_bulk_callback (struct urb *urb)
362 {
363         struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
364         int status = urb->status;
365 
366         dbg("%s - port %d", __FUNCTION__, port->number);
367 
368         port->write_urb_busy = 0;
369         if (status) {
370                 dbg("%s - nonzero write bulk status received: %d",
371                     __FUNCTION__, status);
372                 return;
373         }
374 
375         usb_serial_port_softint(port);
376 }
377 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
378 
379 void usb_serial_generic_throttle (struct usb_serial_port *port)
380 {
381         unsigned long flags;
382 
383         dbg("%s - port %d", __FUNCTION__, port->number);
384 
385         /* Set the throttle request flag. It will be picked up
386          * by usb_serial_generic_read_bulk_callback(). */
387         spin_lock_irqsave(&port->lock, flags);
388         port->throttle_req = 1;
389         spin_unlock_irqrestore(&port->lock, flags);
390 }
391 
392 void usb_serial_generic_unthrottle (struct usb_serial_port *port)
393 {
394         int was_throttled;
395         unsigned long flags;
396 
397         dbg("%s - port %d", __FUNCTION__, port->number);
398 
399         /* Clear the throttle flags */
400         spin_lock_irqsave(&port->lock, flags);
401         was_throttled = port->throttled;
402         port->throttled = port->throttle_req = 0;
403         spin_unlock_irqrestore(&port->lock, flags);
404 
405         if (was_throttled) {
406                 /* Resume reading from device */
407                 resubmit_read_urb(port, GFP_KERNEL);
408         }
409 }
410 
411 void usb_serial_generic_shutdown (struct usb_serial *serial)
412 {
413         int i;
414 
415         dbg("%s", __FUNCTION__);
416 
417         /* stop reads and writes on all ports */
418         for (i=0; i < serial->num_ports; ++i) {
419                 generic_cleanup(serial->port[i]);
420         }
421 }
422 
423 
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