xref: /linux/drivers/usb/serial/ir-usb.c (revision 8c994eff8fcfe8ecb1f1dbebed25b4d7bb75be12) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * USB IR Dongle driver
4  *
5  *	Copyright (C) 2001-2002	Greg Kroah-Hartman (greg@kroah.com)
6  *	Copyright (C) 2002	Gary Brubaker (xavyer@ix.netcom.com)
7  *	Copyright (C) 2010	Johan Hovold (jhovold@gmail.com)
8  *
9  * This driver allows a USB IrDA device to be used as a "dumb" serial device.
10  * This can be useful if you do not have access to a full IrDA stack on the
11  * other side of the connection.  If you do have an IrDA stack on both devices,
12  * please use the usb-irda driver, as it contains the proper error checking and
13  * other goodness of a full IrDA stack.
14  *
15  * Portions of this driver were taken from drivers/net/irda/irda-usb.c, which
16  * was written by Roman Weissgaerber <weissg@vienna.at>, Dag Brattli
17  * <dag@brattli.net>, and Jean Tourrilhes <jt@hpl.hp.com>
18  *
19  * See Documentation/usb/usb-serial.rst for more information on using this
20  * driver
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/errno.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/tty.h>
28 #include <linux/tty_driver.h>
29 #include <linux/tty_flip.h>
30 #include <linux/module.h>
31 #include <linux/spinlock.h>
32 #include <linux/uaccess.h>
33 #include <linux/usb.h>
34 #include <linux/usb/serial.h>
35 #include <linux/usb/irda.h>
36 
37 #define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Johan Hovold <jhovold@gmail.com>"
38 #define DRIVER_DESC "USB IR Dongle driver"
39 
40 /* if overridden by the user, then use their value for the size of the read and
41  * write urbs */
42 static int buffer_size;
43 
44 /* if overridden by the user, then use the specified number of XBOFs */
45 static int xbof = -1;
46 
47 static int  ir_startup (struct usb_serial *serial);
48 static int ir_write(struct tty_struct *tty, struct usb_serial_port *port,
49 		const unsigned char *buf, int count);
50 static unsigned int ir_write_room(struct tty_struct *tty);
51 static void ir_write_bulk_callback(struct urb *urb);
52 static void ir_process_read_urb(struct urb *urb);
53 static void ir_set_termios(struct tty_struct *tty,
54 			   struct usb_serial_port *port,
55 			   const struct ktermios *old_termios);
56 
57 /* Not that this lot means you can only have one per system */
58 static u8 ir_baud;
59 static u8 ir_xbof;
60 static u8 ir_add_bof;
61 
62 static const struct usb_device_id ir_id_table[] = {
63 	{ USB_DEVICE(0x050f, 0x0180) },		/* KC Technology, KC-180 */
64 	{ USB_DEVICE(0x08e9, 0x0100) },		/* XTNDAccess */
65 	{ USB_DEVICE(0x09c4, 0x0011) },		/* ACTiSys ACT-IR2000U */
66 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, USB_SUBCLASS_IRDA, 0) },
67 	{ }					/* Terminating entry */
68 };
69 
70 MODULE_DEVICE_TABLE(usb, ir_id_table);
71 
72 static struct usb_serial_driver ir_device = {
73 	.driver	= {
74 		.owner	= THIS_MODULE,
75 		.name	= "ir-usb",
76 	},
77 	.description		= "IR Dongle",
78 	.id_table		= ir_id_table,
79 	.num_ports		= 1,
80 	.num_bulk_in		= 1,
81 	.num_bulk_out		= 1,
82 	.set_termios		= ir_set_termios,
83 	.attach			= ir_startup,
84 	.write			= ir_write,
85 	.write_room		= ir_write_room,
86 	.write_bulk_callback	= ir_write_bulk_callback,
87 	.process_read_urb	= ir_process_read_urb,
88 };
89 
90 static struct usb_serial_driver * const serial_drivers[] = {
91 	&ir_device, NULL
92 };
93 
94 static inline void irda_usb_dump_class_desc(struct usb_serial *serial,
95 					    struct usb_irda_cs_descriptor *desc)
96 {
97 	struct device *dev = &serial->dev->dev;
98 
99 	dev_dbg(dev, "bLength=%x\n", desc->bLength);
100 	dev_dbg(dev, "bDescriptorType=%x\n", desc->bDescriptorType);
101 	dev_dbg(dev, "bcdSpecRevision=%x\n", __le16_to_cpu(desc->bcdSpecRevision));
102 	dev_dbg(dev, "bmDataSize=%x\n", desc->bmDataSize);
103 	dev_dbg(dev, "bmWindowSize=%x\n", desc->bmWindowSize);
104 	dev_dbg(dev, "bmMinTurnaroundTime=%d\n", desc->bmMinTurnaroundTime);
105 	dev_dbg(dev, "wBaudRate=%x\n", __le16_to_cpu(desc->wBaudRate));
106 	dev_dbg(dev, "bmAdditionalBOFs=%x\n", desc->bmAdditionalBOFs);
107 	dev_dbg(dev, "bIrdaRateSniff=%x\n", desc->bIrdaRateSniff);
108 	dev_dbg(dev, "bMaxUnicastList=%x\n", desc->bMaxUnicastList);
109 }
110 
111 /*------------------------------------------------------------------*/
112 /*
113  * Function irda_usb_find_class_desc(dev, ifnum)
114  *
115  *    Returns instance of IrDA class descriptor, or NULL if not found
116  *
117  * The class descriptor is some extra info that IrDA USB devices will
118  * offer to us, describing their IrDA characteristics. We will use that in
119  * irda_usb_init_qos()
120  *
121  * Based on the same function in drivers/net/irda/irda-usb.c
122  */
123 static struct usb_irda_cs_descriptor *
124 irda_usb_find_class_desc(struct usb_serial *serial, unsigned int ifnum)
125 {
126 	struct usb_device *dev = serial->dev;
127 	struct usb_irda_cs_descriptor *desc;
128 	int ret;
129 
130 	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
131 	if (!desc)
132 		return NULL;
133 
134 	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
135 			USB_REQ_CS_IRDA_GET_CLASS_DESC,
136 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
137 			0, ifnum, desc, sizeof(*desc), 1000);
138 
139 	dev_dbg(&serial->dev->dev, "%s -  ret=%d\n", __func__, ret);
140 	if (ret < (int)sizeof(*desc)) {
141 		dev_dbg(&serial->dev->dev,
142 			"%s - class descriptor read %s (%d)\n", __func__,
143 			(ret < 0) ? "failed" : "too short", ret);
144 		goto error;
145 	}
146 	if (desc->bDescriptorType != USB_DT_CS_IRDA) {
147 		dev_dbg(&serial->dev->dev, "%s - bad class descriptor type\n",
148 			__func__);
149 		goto error;
150 	}
151 
152 	irda_usb_dump_class_desc(serial, desc);
153 	return desc;
154 
155 error:
156 	kfree(desc);
157 	return NULL;
158 }
159 
160 static u8 ir_xbof_change(u8 xbof)
161 {
162 	u8 result;
163 
164 	/* reference irda-usb.c */
165 	switch (xbof) {
166 	case 48:
167 		result = 0x10;
168 		break;
169 	case 28:
170 	case 24:
171 		result = 0x20;
172 		break;
173 	default:
174 	case 12:
175 		result = 0x30;
176 		break;
177 	case  5:
178 	case  6:
179 		result = 0x40;
180 		break;
181 	case  3:
182 		result = 0x50;
183 		break;
184 	case  2:
185 		result = 0x60;
186 		break;
187 	case  1:
188 		result = 0x70;
189 		break;
190 	case  0:
191 		result = 0x80;
192 		break;
193 	}
194 
195 	return(result);
196 }
197 
198 static int ir_startup(struct usb_serial *serial)
199 {
200 	struct usb_irda_cs_descriptor *irda_desc;
201 	int rates;
202 
203 	irda_desc = irda_usb_find_class_desc(serial, 0);
204 	if (!irda_desc) {
205 		dev_err(&serial->dev->dev,
206 			"IRDA class descriptor not found, device not bound\n");
207 		return -ENODEV;
208 	}
209 
210 	rates = le16_to_cpu(irda_desc->wBaudRate);
211 
212 	dev_dbg(&serial->dev->dev,
213 		"%s - Baud rates supported:%s%s%s%s%s%s%s%s%s\n",
214 		__func__,
215 		(rates & USB_IRDA_BR_2400) ? " 2400" : "",
216 		(rates & USB_IRDA_BR_9600) ? " 9600" : "",
217 		(rates & USB_IRDA_BR_19200) ? " 19200" : "",
218 		(rates & USB_IRDA_BR_38400) ? " 38400" : "",
219 		(rates & USB_IRDA_BR_57600) ? " 57600" : "",
220 		(rates & USB_IRDA_BR_115200) ? " 115200" : "",
221 		(rates & USB_IRDA_BR_576000) ? " 576000" : "",
222 		(rates & USB_IRDA_BR_1152000) ? " 1152000" : "",
223 		(rates & USB_IRDA_BR_4000000) ? " 4000000" : "");
224 
225 	switch (irda_desc->bmAdditionalBOFs) {
226 	case USB_IRDA_AB_48:
227 		ir_add_bof = 48;
228 		break;
229 	case USB_IRDA_AB_24:
230 		ir_add_bof = 24;
231 		break;
232 	case USB_IRDA_AB_12:
233 		ir_add_bof = 12;
234 		break;
235 	case USB_IRDA_AB_6:
236 		ir_add_bof = 6;
237 		break;
238 	case USB_IRDA_AB_3:
239 		ir_add_bof = 3;
240 		break;
241 	case USB_IRDA_AB_2:
242 		ir_add_bof = 2;
243 		break;
244 	case USB_IRDA_AB_1:
245 		ir_add_bof = 1;
246 		break;
247 	case USB_IRDA_AB_0:
248 		ir_add_bof = 0;
249 		break;
250 	default:
251 		break;
252 	}
253 
254 	kfree(irda_desc);
255 
256 	return 0;
257 }
258 
259 static int ir_write(struct tty_struct *tty, struct usb_serial_port *port,
260 		const unsigned char *buf, int count)
261 {
262 	struct urb *urb = NULL;
263 	unsigned long flags;
264 	int ret;
265 
266 	if (port->bulk_out_size == 0)
267 		return -EINVAL;
268 
269 	if (count == 0)
270 		return 0;
271 
272 	count = min(count, port->bulk_out_size - 1);
273 
274 	spin_lock_irqsave(&port->lock, flags);
275 	if (__test_and_clear_bit(0, &port->write_urbs_free)) {
276 		urb = port->write_urbs[0];
277 		port->tx_bytes += count;
278 	}
279 	spin_unlock_irqrestore(&port->lock, flags);
280 
281 	if (!urb)
282 		return 0;
283 
284 	/*
285 	 * The first byte of the packet we send to the device contains an
286 	 * outbound header which indicates an additional number of BOFs and
287 	 * a baud rate change.
288 	 *
289 	 * See section 5.4.2.2 of the USB IrDA spec.
290 	 */
291 	*(u8 *)urb->transfer_buffer = ir_xbof | ir_baud;
292 
293 	memcpy(urb->transfer_buffer + 1, buf, count);
294 
295 	urb->transfer_buffer_length = count + 1;
296 	urb->transfer_flags = URB_ZERO_PACKET;
297 
298 	ret = usb_submit_urb(urb, GFP_ATOMIC);
299 	if (ret) {
300 		dev_err(&port->dev, "failed to submit write urb: %d\n", ret);
301 
302 		spin_lock_irqsave(&port->lock, flags);
303 		__set_bit(0, &port->write_urbs_free);
304 		port->tx_bytes -= count;
305 		spin_unlock_irqrestore(&port->lock, flags);
306 
307 		return ret;
308 	}
309 
310 	return count;
311 }
312 
313 static void ir_write_bulk_callback(struct urb *urb)
314 {
315 	struct usb_serial_port *port = urb->context;
316 	int status = urb->status;
317 	unsigned long flags;
318 
319 	spin_lock_irqsave(&port->lock, flags);
320 	__set_bit(0, &port->write_urbs_free);
321 	port->tx_bytes -= urb->transfer_buffer_length - 1;
322 	spin_unlock_irqrestore(&port->lock, flags);
323 
324 	switch (status) {
325 	case 0:
326 		break;
327 	case -ENOENT:
328 	case -ECONNRESET:
329 	case -ESHUTDOWN:
330 		dev_dbg(&port->dev, "write urb stopped: %d\n", status);
331 		return;
332 	case -EPIPE:
333 		dev_err(&port->dev, "write urb stopped: %d\n", status);
334 		return;
335 	default:
336 		dev_err(&port->dev, "nonzero write-urb status: %d\n", status);
337 		break;
338 	}
339 
340 	usb_serial_port_softint(port);
341 }
342 
343 static unsigned int ir_write_room(struct tty_struct *tty)
344 {
345 	struct usb_serial_port *port = tty->driver_data;
346 	unsigned int count = 0;
347 
348 	if (port->bulk_out_size == 0)
349 		return 0;
350 
351 	if (test_bit(0, &port->write_urbs_free))
352 		count = port->bulk_out_size - 1;
353 
354 	return count;
355 }
356 
357 static void ir_process_read_urb(struct urb *urb)
358 {
359 	struct usb_serial_port *port = urb->context;
360 	unsigned char *data = urb->transfer_buffer;
361 
362 	if (!urb->actual_length)
363 		return;
364 	/*
365 	 * The first byte of the packet we get from the device
366 	 * contains a busy indicator and baud rate change.
367 	 * See section 5.4.1.2 of the USB IrDA spec.
368 	 */
369 	if (*data & 0x0f)
370 		ir_baud = *data & 0x0f;
371 
372 	if (urb->actual_length == 1)
373 		return;
374 
375 	tty_insert_flip_string(&port->port, data + 1, urb->actual_length - 1);
376 	tty_flip_buffer_push(&port->port);
377 }
378 
379 static void ir_set_termios(struct tty_struct *tty,
380 			   struct usb_serial_port *port,
381 			   const struct ktermios *old_termios)
382 {
383 	struct usb_device *udev = port->serial->dev;
384 	unsigned char *transfer_buffer;
385 	int actual_length;
386 	speed_t baud;
387 	int ir_baud;
388 	int ret;
389 
390 	baud = tty_get_baud_rate(tty);
391 
392 	/*
393 	 * FIXME, we should compare the baud request against the
394 	 * capability stated in the IR header that we got in the
395 	 * startup function.
396 	 */
397 
398 	switch (baud) {
399 	case 2400:
400 		ir_baud = USB_IRDA_LS_2400;
401 		break;
402 	case 9600:
403 		ir_baud = USB_IRDA_LS_9600;
404 		break;
405 	case 19200:
406 		ir_baud = USB_IRDA_LS_19200;
407 		break;
408 	case 38400:
409 		ir_baud = USB_IRDA_LS_38400;
410 		break;
411 	case 57600:
412 		ir_baud = USB_IRDA_LS_57600;
413 		break;
414 	case 115200:
415 		ir_baud = USB_IRDA_LS_115200;
416 		break;
417 	case 576000:
418 		ir_baud = USB_IRDA_LS_576000;
419 		break;
420 	case 1152000:
421 		ir_baud = USB_IRDA_LS_1152000;
422 		break;
423 	case 4000000:
424 		ir_baud = USB_IRDA_LS_4000000;
425 		break;
426 	default:
427 		ir_baud = USB_IRDA_LS_9600;
428 		baud = 9600;
429 	}
430 
431 	if (xbof == -1)
432 		ir_xbof = ir_xbof_change(ir_add_bof);
433 	else
434 		ir_xbof = ir_xbof_change(xbof) ;
435 
436 	/* Only speed changes are supported */
437 	tty_termios_copy_hw(&tty->termios, old_termios);
438 	tty_encode_baud_rate(tty, baud, baud);
439 
440 	/*
441 	 * send the baud change out on an "empty" data packet
442 	 */
443 	transfer_buffer = kmalloc(1, GFP_KERNEL);
444 	if (!transfer_buffer)
445 		return;
446 
447 	*transfer_buffer = ir_xbof | ir_baud;
448 
449 	ret = usb_bulk_msg(udev,
450 			usb_sndbulkpipe(udev, port->bulk_out_endpointAddress),
451 			transfer_buffer, 1, &actual_length, 5000);
452 	if (ret || actual_length != 1) {
453 		if (!ret)
454 			ret = -EIO;
455 		dev_err(&port->dev, "failed to change line speed: %d\n", ret);
456 	}
457 
458 	kfree(transfer_buffer);
459 }
460 
461 static int __init ir_init(void)
462 {
463 	if (buffer_size) {
464 		ir_device.bulk_in_size = buffer_size;
465 		ir_device.bulk_out_size = buffer_size;
466 	}
467 
468 	return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, ir_id_table);
469 }
470 
471 static void __exit ir_exit(void)
472 {
473 	usb_serial_deregister_drivers(serial_drivers);
474 }
475 
476 
477 module_init(ir_init);
478 module_exit(ir_exit);
479 
480 MODULE_AUTHOR(DRIVER_AUTHOR);
481 MODULE_DESCRIPTION(DRIVER_DESC);
482 MODULE_LICENSE("GPL");
483 
484 module_param(xbof, int, 0);
485 MODULE_PARM_DESC(xbof, "Force specific number of XBOFs");
486 module_param(buffer_size, int, 0);
487 MODULE_PARM_DESC(buffer_size, "Size of the transfer buffers");
488 
489