Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
/*
 * Belkin USB Serial Adapter Driver
 *
 *  Copyright (C) 2000		William Greathouse (wgreathouse@smva.com)
 *  Copyright (C) 2000-2001	Greg Kroah-Hartman (greg@kroah.com)
 *  Copyright (C) 2010		Johan Hovold (jhovold@gmail.com)
 *
 *  This program is largely derived from work by the linux-usb group
 *  and associated source files.  Please see the usb/serial files for
 *  individual credits and copyrights.
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 *
 * TODO:
 * -- Add true modem control line query capability.  Currently we track the
 *    states reported by the interrupt and the states we request.
 * -- Add support for flush commands
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include "belkin_sa.h"

#define DRIVER_AUTHOR "William Greathouse <wgreathouse@smva.com>"
#define DRIVER_DESC "USB Belkin Serial converter driver"

/* function prototypes for a Belkin USB Serial Adapter F5U103 */
static int belkin_sa_port_probe(struct usb_serial_port *port);
static int belkin_sa_port_remove(struct usb_serial_port *port);
static int  belkin_sa_open(struct tty_struct *tty,
			struct usb_serial_port *port);
static void belkin_sa_close(struct usb_serial_port *port);
static void belkin_sa_read_int_callback(struct urb *urb);
static void belkin_sa_process_read_urb(struct urb *urb);
static void belkin_sa_set_termios(struct tty_struct *tty,
			struct usb_serial_port *port, struct ktermios * old);
static void belkin_sa_break_ctl(struct tty_struct *tty, int break_state);
static int  belkin_sa_tiocmget(struct tty_struct *tty);
static int  belkin_sa_tiocmset(struct tty_struct *tty,
					unsigned int set, unsigned int clear);


static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(BELKIN_SA_VID, BELKIN_SA_PID) },
	{ USB_DEVICE(BELKIN_OLD_VID, BELKIN_OLD_PID) },
	{ USB_DEVICE(PERACOM_VID, PERACOM_PID) },
	{ USB_DEVICE(GOHUBS_VID, GOHUBS_PID) },
	{ USB_DEVICE(GOHUBS_VID, HANDYLINK_PID) },
	{ USB_DEVICE(BELKIN_DOCKSTATION_VID, BELKIN_DOCKSTATION_PID) },
	{ }	/* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, id_table);

/* All of the device info needed for the serial converters */
static struct usb_serial_driver belkin_device = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"belkin",
	},
	.description =		"Belkin / Peracom / GoHubs USB Serial Adapter",
	.id_table =		id_table,
	.num_ports =		1,
	.open =			belkin_sa_open,
	.close =		belkin_sa_close,
	.read_int_callback =	belkin_sa_read_int_callback,
	.process_read_urb =	belkin_sa_process_read_urb,
	.set_termios =		belkin_sa_set_termios,
	.break_ctl =		belkin_sa_break_ctl,
	.tiocmget =		belkin_sa_tiocmget,
	.tiocmset =		belkin_sa_tiocmset,
	.port_probe =		belkin_sa_port_probe,
	.port_remove =		belkin_sa_port_remove,
};

static struct usb_serial_driver * const serial_drivers[] = {
	&belkin_device, NULL
};

struct belkin_sa_private {
	spinlock_t		lock;
	unsigned long		control_state;
	unsigned char		last_lsr;
	unsigned char		last_msr;
	int			bad_flow_control;
};


/*
 * ***************************************************************************
 * Belkin USB Serial Adapter F5U103 specific driver functions
 * ***************************************************************************
 */

#define WDR_TIMEOUT 5000 /* default urb timeout */

/* assumes that struct usb_serial *serial is available */
#define BSA_USB_CMD(c, v) usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), \
					    (c), BELKIN_SA_SET_REQUEST_TYPE, \
					    (v), 0, NULL, 0, WDR_TIMEOUT)

static int belkin_sa_port_probe(struct usb_serial_port *port)
{
	struct usb_device *dev = port->serial->dev;
	struct belkin_sa_private *priv;

	priv = kmalloc(sizeof(struct belkin_sa_private), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	spin_lock_init(&priv->lock);
	priv->control_state = 0;
	priv->last_lsr = 0;
	priv->last_msr = 0;
	/* see comments at top of file */
	priv->bad_flow_control =
		(le16_to_cpu(dev->descriptor.bcdDevice) <= 0x0206) ? 1 : 0;
	dev_info(&dev->dev, "bcdDevice: %04x, bfc: %d\n",
					le16_to_cpu(dev->descriptor.bcdDevice),
					priv->bad_flow_control);

	usb_set_serial_port_data(port, priv);

	return 0;
}

static int belkin_sa_port_remove(struct usb_serial_port *port)
{
	struct belkin_sa_private *priv;

	priv = usb_get_serial_port_data(port);
	kfree(priv);

	return 0;
}

static int belkin_sa_open(struct tty_struct *tty,
					struct usb_serial_port *port)
{
	int retval;

	retval = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	if (retval) {
		dev_err(&port->dev, "usb_submit_urb(read int) failed\n");
		return retval;
	}

	retval = usb_serial_generic_open(tty, port);
	if (retval)
		usb_kill_urb(port->interrupt_in_urb);

	return retval;
}

static void belkin_sa_close(struct usb_serial_port *port)
{
	usb_serial_generic_close(port);
	usb_kill_urb(port->interrupt_in_urb);
}

static void belkin_sa_read_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct belkin_sa_private *priv;
	unsigned char *data = urb->transfer_buffer;
	int retval;
	int status = urb->status;
	unsigned long flags;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
			__func__, status);
		return;
	default:
		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
			__func__, status);
		goto exit;
	}

	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);

	/* Handle known interrupt data */
	/* ignore data[0] and data[1] */

	priv = usb_get_serial_port_data(port);
	spin_lock_irqsave(&priv->lock, flags);
	priv->last_msr = data[BELKIN_SA_MSR_INDEX];

	/* Record Control Line states */
	if (priv->last_msr & BELKIN_SA_MSR_DSR)
		priv->control_state |= TIOCM_DSR;
	else
		priv->control_state &= ~TIOCM_DSR;

	if (priv->last_msr & BELKIN_SA_MSR_CTS)
		priv->control_state |= TIOCM_CTS;
	else
		priv->control_state &= ~TIOCM_CTS;

	if (priv->last_msr & BELKIN_SA_MSR_RI)
		priv->control_state |= TIOCM_RI;
	else
		priv->control_state &= ~TIOCM_RI;

	if (priv->last_msr & BELKIN_SA_MSR_CD)
		priv->control_state |= TIOCM_CD;
	else
		priv->control_state &= ~TIOCM_CD;

	priv->last_lsr = data[BELKIN_SA_LSR_INDEX];
	spin_unlock_irqrestore(&priv->lock, flags);
exit:
	retval = usb_submit_urb(urb, GFP_ATOMIC);
	if (retval)
		dev_err(&port->dev, "%s - usb_submit_urb failed with "
			"result %d\n", __func__, retval);
}

static void belkin_sa_process_read_urb(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct belkin_sa_private *priv = usb_get_serial_port_data(port);
	unsigned char *data = urb->transfer_buffer;
	unsigned long flags;
	unsigned char status;
	char tty_flag;

	/* Update line status */
	tty_flag = TTY_NORMAL;

	spin_lock_irqsave(&priv->lock, flags);
	status = priv->last_lsr;
	priv->last_lsr &= ~BELKIN_SA_LSR_ERR;
	spin_unlock_irqrestore(&priv->lock, flags);

	if (!urb->actual_length)
		return;

	if (status & BELKIN_SA_LSR_ERR) {
		/* Break takes precedence over parity, which takes precedence
		 * over framing errors. */
		if (status & BELKIN_SA_LSR_BI)
			tty_flag = TTY_BREAK;
		else if (status & BELKIN_SA_LSR_PE)
			tty_flag = TTY_PARITY;
		else if (status & BELKIN_SA_LSR_FE)
			tty_flag = TTY_FRAME;
		dev_dbg(&port->dev, "tty_flag = %d\n", tty_flag);

		/* Overrun is special, not associated with a char. */
		if (status & BELKIN_SA_LSR_OE)
			tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
	}

	tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
							urb->actual_length);
	tty_flip_buffer_push(&port->port);
}

static void belkin_sa_set_termios(struct tty_struct *tty,
		struct usb_serial_port *port, struct ktermios *old_termios)
{
	struct usb_serial *serial = port->serial;
	struct belkin_sa_private *priv = usb_get_serial_port_data(port);
	unsigned int iflag;
	unsigned int cflag;
	unsigned int old_iflag = 0;
	unsigned int old_cflag = 0;
	__u16 urb_value = 0; /* Will hold the new flags */
	unsigned long flags;
	unsigned long control_state;
	int bad_flow_control;
	speed_t baud;
	struct ktermios *termios = &tty->termios;

	iflag = termios->c_iflag;
	cflag = termios->c_cflag;

	termios->c_cflag &= ~CMSPAR;

	/* get a local copy of the current port settings */
	spin_lock_irqsave(&priv->lock, flags);
	control_state = priv->control_state;
	bad_flow_control = priv->bad_flow_control;
	spin_unlock_irqrestore(&priv->lock, flags);

	old_iflag = old_termios->c_iflag;
	old_cflag = old_termios->c_cflag;

	/* Set the baud rate */
	if ((cflag & CBAUD) != (old_cflag & CBAUD)) {
		/* reassert DTR and (maybe) RTS on transition from B0 */
		if ((old_cflag & CBAUD) == B0) {
			control_state |= (TIOCM_DTR|TIOCM_RTS);
			if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 1) < 0)
				dev_err(&port->dev, "Set DTR error\n");
			/* don't set RTS if using hardware flow control */
			if (!(old_cflag & CRTSCTS))
				if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST
								, 1) < 0)
					dev_err(&port->dev, "Set RTS error\n");
		}
	}

	baud = tty_get_baud_rate(tty);
	if (baud) {
		urb_value = BELKIN_SA_BAUD(baud);
		/* Clip to maximum speed */
		if (urb_value == 0)
			urb_value = 1;
		/* Turn it back into a resulting real baud rate */
		baud = BELKIN_SA_BAUD(urb_value);

		/* Report the actual baud rate back to the caller */
		tty_encode_baud_rate(tty, baud, baud);
		if (BSA_USB_CMD(BELKIN_SA_SET_BAUDRATE_REQUEST, urb_value) < 0)
			dev_err(&port->dev, "Set baudrate error\n");
	} else {
		/* Disable flow control */
		if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST,
						BELKIN_SA_FLOW_NONE) < 0)
			dev_err(&port->dev, "Disable flowcontrol error\n");
		/* Drop RTS and DTR */
		control_state &= ~(TIOCM_DTR | TIOCM_RTS);
		if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 0) < 0)
			dev_err(&port->dev, "DTR LOW error\n");
		if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 0) < 0)
			dev_err(&port->dev, "RTS LOW error\n");
	}

	/* set the parity */
	if ((cflag ^ old_cflag) & (PARENB | PARODD)) {
		if (cflag & PARENB)
			urb_value = (cflag & PARODD) ?  BELKIN_SA_PARITY_ODD
						: BELKIN_SA_PARITY_EVEN;
		else
			urb_value = BELKIN_SA_PARITY_NONE;
		if (BSA_USB_CMD(BELKIN_SA_SET_PARITY_REQUEST, urb_value) < 0)
			dev_err(&port->dev, "Set parity error\n");
	}

	/* set the number of data bits */
	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
		switch (cflag & CSIZE) {
		case CS5:
			urb_value = BELKIN_SA_DATA_BITS(5);
			break;
		case CS6:
			urb_value = BELKIN_SA_DATA_BITS(6);
			break;
		case CS7:
			urb_value = BELKIN_SA_DATA_BITS(7);
			break;
		case CS8:
			urb_value = BELKIN_SA_DATA_BITS(8);
			break;
		default:
			dev_dbg(&port->dev,
				"CSIZE was not CS5-CS8, using default of 8\n");
			urb_value = BELKIN_SA_DATA_BITS(8);
			break;
		}
		if (BSA_USB_CMD(BELKIN_SA_SET_DATA_BITS_REQUEST, urb_value) < 0)
			dev_err(&port->dev, "Set data bits error\n");
	}

	/* set the number of stop bits */
	if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
		urb_value = (cflag & CSTOPB) ? BELKIN_SA_STOP_BITS(2)
						: BELKIN_SA_STOP_BITS(1);
		if (BSA_USB_CMD(BELKIN_SA_SET_STOP_BITS_REQUEST,
							urb_value) < 0)
			dev_err(&port->dev, "Set stop bits error\n");
	}

	/* Set flow control */
	if (((iflag ^ old_iflag) & (IXOFF | IXON)) ||
		((cflag ^ old_cflag) & CRTSCTS)) {
		urb_value = 0;
		if ((iflag & IXOFF) || (iflag & IXON))
			urb_value |= (BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON);
		else
			urb_value &= ~(BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON);

		if (cflag & CRTSCTS)
			urb_value |=  (BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS);
		else
			urb_value &= ~(BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS);

		if (bad_flow_control)
			urb_value &= ~(BELKIN_SA_FLOW_IRTS);

		if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, urb_value) < 0)
			dev_err(&port->dev, "Set flow control error\n");
	}

	/* save off the modified port settings */
	spin_lock_irqsave(&priv->lock, flags);
	priv->control_state = control_state;
	spin_unlock_irqrestore(&priv->lock, flags);
}

static void belkin_sa_break_ctl(struct tty_struct *tty, int break_state)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;

	if (BSA_USB_CMD(BELKIN_SA_SET_BREAK_REQUEST, break_state ? 1 : 0) < 0)
		dev_err(&port->dev, "Set break_ctl %d\n", break_state);
}

static int belkin_sa_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct belkin_sa_private *priv = usb_get_serial_port_data(port);
	unsigned long control_state;
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	control_state = priv->control_state;
	spin_unlock_irqrestore(&priv->lock, flags);

	return control_state;
}

static int belkin_sa_tiocmset(struct tty_struct *tty,
			       unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;
	struct belkin_sa_private *priv = usb_get_serial_port_data(port);
	unsigned long control_state;
	unsigned long flags;
	int retval;
	int rts = 0;
	int dtr = 0;

	spin_lock_irqsave(&priv->lock, flags);
	control_state = priv->control_state;

	if (set & TIOCM_RTS) {
		control_state |= TIOCM_RTS;
		rts = 1;
	}
	if (set & TIOCM_DTR) {
		control_state |= TIOCM_DTR;
		dtr = 1;
	}
	if (clear & TIOCM_RTS) {
		control_state &= ~TIOCM_RTS;
		rts = 0;
	}
	if (clear & TIOCM_DTR) {
		control_state &= ~TIOCM_DTR;
		dtr = 0;
	}

	priv->control_state = control_state;
	spin_unlock_irqrestore(&priv->lock, flags);

	retval = BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, rts);
	if (retval < 0) {
		dev_err(&port->dev, "Set RTS error %d\n", retval);
		goto exit;
	}

	retval = BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, dtr);
	if (retval < 0) {
		dev_err(&port->dev, "Set DTR error %d\n", retval);
		goto exit;
	}
exit:
	return retval;
}

module_usb_serial_driver(serial_drivers, id_table);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");