xref: /openbmc/linux/drivers/usb/serial/pl2303.c (revision 5534b673)
1 /*
2  * Prolific PL2303 USB to serial adaptor driver
3  *
4  * Copyright (C) 2001-2007 Greg Kroah-Hartman (greg@kroah.com)
5  * Copyright (C) 2003 IBM Corp.
6  *
7  * Original driver for 2.2.x by anonymous
8  *
9  *	This program is free software; you can redistribute it and/or
10  *	modify it under the terms of the GNU General Public License version
11  *	2 as published by the Free Software Foundation.
12  *
13  * See Documentation/usb/usb-serial.txt for more information on using this
14  * driver
15  */
16 
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 #include <linux/tty.h>
21 #include <linux/tty_driver.h>
22 #include <linux/tty_flip.h>
23 #include <linux/serial.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/spinlock.h>
27 #include <linux/uaccess.h>
28 #include <linux/usb.h>
29 #include <linux/usb/serial.h>
30 #include <asm/unaligned.h>
31 #include "pl2303.h"
32 
33 
34 #define PL2303_QUIRK_UART_STATE_IDX0		BIT(0)
35 #define PL2303_QUIRK_LEGACY			BIT(1)
36 
37 static const struct usb_device_id id_table[] = {
38 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID) },
39 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ2) },
40 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_DCU11) },
41 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_RSAQ3) },
42 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_PHAROS) },
43 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_ALDIGA) },
44 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_MMX) },
45 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_GPRS) },
46 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_HCR331) },
47 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_MOTOROLA) },
48 	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID_ZTEK) },
49 	{ USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID) },
50 	{ USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID_RSAQ5) },
51 	{ USB_DEVICE(ATEN_VENDOR_ID, ATEN_PRODUCT_ID) },
52 	{ USB_DEVICE(ATEN_VENDOR_ID2, ATEN_PRODUCT_ID) },
53 	{ USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID) },
54 	{ USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID_UCSGT) },
55 	{ USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID) },
56 	{ USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID_2080) },
57 	{ USB_DEVICE(MA620_VENDOR_ID, MA620_PRODUCT_ID) },
58 	{ USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID) },
59 	{ USB_DEVICE(TRIPP_VENDOR_ID, TRIPP_PRODUCT_ID) },
60 	{ USB_DEVICE(RADIOSHACK_VENDOR_ID, RADIOSHACK_PRODUCT_ID) },
61 	{ USB_DEVICE(DCU10_VENDOR_ID, DCU10_PRODUCT_ID) },
62 	{ USB_DEVICE(SITECOM_VENDOR_ID, SITECOM_PRODUCT_ID) },
63 	{ USB_DEVICE(ALCATEL_VENDOR_ID, ALCATEL_PRODUCT_ID) },
64 	{ USB_DEVICE(SAMSUNG_VENDOR_ID, SAMSUNG_PRODUCT_ID) },
65 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_SX1),
66 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
67 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X65),
68 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
69 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X75),
70 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
71 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_EF81) },
72 	{ USB_DEVICE(BENQ_VENDOR_ID, BENQ_PRODUCT_ID_S81) }, /* Benq/Siemens S81 */
73 	{ USB_DEVICE(SYNTECH_VENDOR_ID, SYNTECH_PRODUCT_ID) },
74 	{ USB_DEVICE(NOKIA_CA42_VENDOR_ID, NOKIA_CA42_PRODUCT_ID) },
75 	{ USB_DEVICE(CA_42_CA42_VENDOR_ID, CA_42_CA42_PRODUCT_ID) },
76 	{ USB_DEVICE(SAGEM_VENDOR_ID, SAGEM_PRODUCT_ID) },
77 	{ USB_DEVICE(LEADTEK_VENDOR_ID, LEADTEK_9531_PRODUCT_ID) },
78 	{ USB_DEVICE(SPEEDDRAGON_VENDOR_ID, SPEEDDRAGON_PRODUCT_ID) },
79 	{ USB_DEVICE(DATAPILOT_U2_VENDOR_ID, DATAPILOT_U2_PRODUCT_ID) },
80 	{ USB_DEVICE(BELKIN_VENDOR_ID, BELKIN_PRODUCT_ID) },
81 	{ USB_DEVICE(ALCOR_VENDOR_ID, ALCOR_PRODUCT_ID) },
82 	{ USB_DEVICE(WS002IN_VENDOR_ID, WS002IN_PRODUCT_ID) },
83 	{ USB_DEVICE(COREGA_VENDOR_ID, COREGA_PRODUCT_ID) },
84 	{ USB_DEVICE(YCCABLE_VENDOR_ID, YCCABLE_PRODUCT_ID) },
85 	{ USB_DEVICE(SUPERIAL_VENDOR_ID, SUPERIAL_PRODUCT_ID) },
86 	{ USB_DEVICE(HP_VENDOR_ID, HP_LD220_PRODUCT_ID) },
87 	{ USB_DEVICE(HP_VENDOR_ID, HP_LD960_PRODUCT_ID) },
88 	{ USB_DEVICE(HP_VENDOR_ID, HP_LCM220_PRODUCT_ID) },
89 	{ USB_DEVICE(HP_VENDOR_ID, HP_LCM960_PRODUCT_ID) },
90 	{ USB_DEVICE(CRESSI_VENDOR_ID, CRESSI_EDY_PRODUCT_ID) },
91 	{ USB_DEVICE(ZEAGLE_VENDOR_ID, ZEAGLE_N2ITION3_PRODUCT_ID) },
92 	{ USB_DEVICE(SONY_VENDOR_ID, SONY_QN3USB_PRODUCT_ID) },
93 	{ USB_DEVICE(SANWA_VENDOR_ID, SANWA_PRODUCT_ID) },
94 	{ USB_DEVICE(ADLINK_VENDOR_ID, ADLINK_ND6530_PRODUCT_ID) },
95 	{ USB_DEVICE(SMART_VENDOR_ID, SMART_PRODUCT_ID) },
96 	{ }					/* Terminating entry */
97 };
98 
99 MODULE_DEVICE_TABLE(usb, id_table);
100 
101 #define SET_LINE_REQUEST_TYPE		0x21
102 #define SET_LINE_REQUEST		0x20
103 
104 #define SET_CONTROL_REQUEST_TYPE	0x21
105 #define SET_CONTROL_REQUEST		0x22
106 #define CONTROL_DTR			0x01
107 #define CONTROL_RTS			0x02
108 
109 #define BREAK_REQUEST_TYPE		0x21
110 #define BREAK_REQUEST			0x23
111 #define BREAK_ON			0xffff
112 #define BREAK_OFF			0x0000
113 
114 #define GET_LINE_REQUEST_TYPE		0xa1
115 #define GET_LINE_REQUEST		0x21
116 
117 #define VENDOR_WRITE_REQUEST_TYPE	0x40
118 #define VENDOR_WRITE_REQUEST		0x01
119 
120 #define VENDOR_READ_REQUEST_TYPE	0xc0
121 #define VENDOR_READ_REQUEST		0x01
122 
123 #define UART_STATE_INDEX		8
124 #define UART_STATE_MSR_MASK		0x8b
125 #define UART_STATE_TRANSIENT_MASK	0x74
126 #define UART_DCD			0x01
127 #define UART_DSR			0x02
128 #define UART_BREAK_ERROR		0x04
129 #define UART_RING			0x08
130 #define UART_FRAME_ERROR		0x10
131 #define UART_PARITY_ERROR		0x20
132 #define UART_OVERRUN_ERROR		0x40
133 #define UART_CTS			0x80
134 
135 
136 enum pl2303_type {
137 	TYPE_01,	/* Type 0 and 1 (difference unknown) */
138 	TYPE_HX,	/* HX version of the pl2303 chip */
139 	TYPE_COUNT
140 };
141 
142 struct pl2303_type_data {
143 	speed_t max_baud_rate;
144 	unsigned long quirks;
145 };
146 
147 struct pl2303_serial_private {
148 	const struct pl2303_type_data *type;
149 	unsigned long quirks;
150 };
151 
152 struct pl2303_private {
153 	spinlock_t lock;
154 	u8 line_control;
155 	u8 line_status;
156 
157 	u8 line_settings[7];
158 };
159 
160 static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
161 	[TYPE_01] = {
162 		.max_baud_rate =	1228800,
163 		.quirks =		PL2303_QUIRK_LEGACY,
164 	},
165 };
166 
167 static int pl2303_vendor_read(struct usb_serial *serial, u16 value,
168 							unsigned char buf[1])
169 {
170 	struct device *dev = &serial->interface->dev;
171 	int res;
172 
173 	res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
174 			VENDOR_READ_REQUEST, VENDOR_READ_REQUEST_TYPE,
175 			value, 0, buf, 1, 100);
176 	if (res != 1) {
177 		dev_err(dev, "%s - failed to read [%04x]: %d\n", __func__,
178 								value, res);
179 		if (res >= 0)
180 			res = -EIO;
181 
182 		return res;
183 	}
184 
185 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, buf[0]);
186 
187 	return 0;
188 }
189 
190 static int pl2303_vendor_write(struct usb_serial *serial, u16 value, u16 index)
191 {
192 	struct device *dev = &serial->interface->dev;
193 	int res;
194 
195 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, index);
196 
197 	res = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
198 			VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
199 			value, index, NULL, 0, 100);
200 	if (res) {
201 		dev_err(dev, "%s - failed to write [%04x]: %d\n", __func__,
202 								value, res);
203 		return res;
204 	}
205 
206 	return 0;
207 }
208 
209 static int pl2303_probe(struct usb_serial *serial,
210 					const struct usb_device_id *id)
211 {
212 	usb_set_serial_data(serial, (void *)id->driver_info);
213 
214 	return 0;
215 }
216 
217 static int pl2303_startup(struct usb_serial *serial)
218 {
219 	struct pl2303_serial_private *spriv;
220 	enum pl2303_type type = TYPE_01;
221 	unsigned char *buf;
222 
223 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
224 	if (!spriv)
225 		return -ENOMEM;
226 
227 	buf = kmalloc(1, GFP_KERNEL);
228 	if (!buf) {
229 		kfree(spriv);
230 		return -ENOMEM;
231 	}
232 
233 	if (serial->dev->descriptor.bDeviceClass == 0x02)
234 		type = TYPE_01;		/* type 0 */
235 	else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40)
236 		type = TYPE_HX;
237 	else if (serial->dev->descriptor.bDeviceClass == 0x00)
238 		type = TYPE_01;		/* type 1 */
239 	else if (serial->dev->descriptor.bDeviceClass == 0xFF)
240 		type = TYPE_01;		/* type 1 */
241 	dev_dbg(&serial->interface->dev, "device type: %d\n", type);
242 
243 	spriv->type = &pl2303_type_data[type];
244 	spriv->quirks = (unsigned long)usb_get_serial_data(serial);
245 	spriv->quirks |= spriv->type->quirks;
246 
247 	usb_set_serial_data(serial, spriv);
248 
249 	pl2303_vendor_read(serial, 0x8484, buf);
250 	pl2303_vendor_write(serial, 0x0404, 0);
251 	pl2303_vendor_read(serial, 0x8484, buf);
252 	pl2303_vendor_read(serial, 0x8383, buf);
253 	pl2303_vendor_read(serial, 0x8484, buf);
254 	pl2303_vendor_write(serial, 0x0404, 1);
255 	pl2303_vendor_read(serial, 0x8484, buf);
256 	pl2303_vendor_read(serial, 0x8383, buf);
257 	pl2303_vendor_write(serial, 0, 1);
258 	pl2303_vendor_write(serial, 1, 0);
259 	if (spriv->quirks & PL2303_QUIRK_LEGACY)
260 		pl2303_vendor_write(serial, 2, 0x24);
261 	else
262 		pl2303_vendor_write(serial, 2, 0x44);
263 
264 	kfree(buf);
265 
266 	return 0;
267 }
268 
269 static void pl2303_release(struct usb_serial *serial)
270 {
271 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
272 
273 	kfree(spriv);
274 }
275 
276 static int pl2303_port_probe(struct usb_serial_port *port)
277 {
278 	struct pl2303_private *priv;
279 
280 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
281 	if (!priv)
282 		return -ENOMEM;
283 
284 	spin_lock_init(&priv->lock);
285 
286 	usb_set_serial_port_data(port, priv);
287 
288 	port->port.drain_delay = 256;
289 
290 	return 0;
291 }
292 
293 static int pl2303_port_remove(struct usb_serial_port *port)
294 {
295 	struct pl2303_private *priv = usb_get_serial_port_data(port);
296 
297 	kfree(priv);
298 
299 	return 0;
300 }
301 
302 static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value)
303 {
304 	struct usb_device *dev = port->serial->dev;
305 	int retval;
306 
307 	dev_dbg(&port->dev, "%s - %02x\n", __func__, value);
308 
309 	retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
310 				 SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE,
311 				 value, 0, NULL, 0, 100);
312 	if (retval)
313 		dev_err(&port->dev, "%s - failed: %d\n", __func__, retval);
314 
315 	return retval;
316 }
317 
318 /*
319  * Returns the nearest supported baud rate that can be set directly without
320  * using divisors.
321  */
322 static speed_t pl2303_get_supported_baud_rate(speed_t baud)
323 {
324 	static const speed_t baud_sup[] = {
325 		75, 150, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200, 9600,
326 		14400, 19200, 28800, 38400, 57600, 115200, 230400, 460800,
327 		614400, 921600, 1228800, 2457600, 3000000, 6000000
328 	};
329 
330 	unsigned i;
331 
332 	for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
333 		if (baud_sup[i] > baud)
334 			break;
335 	}
336 
337 	if (i == ARRAY_SIZE(baud_sup))
338 		baud = baud_sup[i - 1];
339 	else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
340 		baud = baud_sup[i - 1];
341 	else
342 		baud = baud_sup[i];
343 
344 	return baud;
345 }
346 
347 /*
348  * NOTE: If unsupported baud rates are set directly, the PL2303 seems to
349  *       use 9600 baud.
350  */
351 static speed_t pl2303_encode_baud_rate_direct(unsigned char buf[4],
352 								speed_t baud)
353 {
354 	put_unaligned_le32(baud, buf);
355 
356 	return baud;
357 }
358 
359 static speed_t pl2303_encode_baud_rate_divisor(unsigned char buf[4],
360 								speed_t baud)
361 {
362 	unsigned int tmp;
363 
364 	/*
365 	 * Apparently the formula is:
366 	 * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
367 	 */
368 	tmp = 12000000 * 32 / baud;
369 	buf[3] = 0x80;
370 	buf[2] = 0;
371 	buf[1] = (tmp >= 256);
372 	while (tmp >= 256) {
373 		tmp >>= 2;
374 		buf[1] <<= 1;
375 	}
376 	buf[0] = tmp;
377 
378 	return baud;
379 }
380 
381 static void pl2303_encode_baud_rate(struct tty_struct *tty,
382 					struct usb_serial_port *port,
383 					u8 buf[4])
384 {
385 	struct usb_serial *serial = port->serial;
386 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
387 	speed_t	baud_sup;
388 	speed_t baud;
389 
390 	baud = tty_get_baud_rate(tty);
391 	dev_dbg(&port->dev, "baud requested = %u\n", baud);
392 	if (!baud)
393 		return;
394 
395 	if (spriv->type->max_baud_rate)
396 		baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
397 	/*
398 	 * Set baud rate to nearest supported value.
399 	 *
400 	 * NOTE: Baud rate 500k can only be set using divisors.
401 	 */
402 	baud_sup = pl2303_get_supported_baud_rate(baud);
403 
404 	if (baud == 500000)
405 		baud = pl2303_encode_baud_rate_divisor(buf, baud);
406 	else
407 		baud = pl2303_encode_baud_rate_direct(buf, baud_sup);
408 
409 	/* Save resulting baud rate */
410 	tty_encode_baud_rate(tty, baud, baud);
411 	dev_dbg(&port->dev, "baud set = %u\n", baud);
412 }
413 
414 static int pl2303_get_line_request(struct usb_serial_port *port,
415 							unsigned char buf[7])
416 {
417 	struct usb_device *udev = port->serial->dev;
418 	int ret;
419 
420 	ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
421 				GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
422 				0, 0, buf, 7, 100);
423 	if (ret != 7) {
424 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
425 
426 		if (ret > 0)
427 			ret = -EIO;
428 
429 		return ret;
430 	}
431 
432 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
433 
434 	return 0;
435 }
436 
437 static int pl2303_set_line_request(struct usb_serial_port *port,
438 							unsigned char buf[7])
439 {
440 	struct usb_device *udev = port->serial->dev;
441 	int ret;
442 
443 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
444 				SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
445 				0, 0, buf, 7, 100);
446 	if (ret != 7) {
447 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
448 
449 		if (ret > 0)
450 			ret = -EIO;
451 
452 		return ret;
453 	}
454 
455 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
456 
457 	return 0;
458 }
459 
460 static void pl2303_set_termios(struct tty_struct *tty,
461 		struct usb_serial_port *port, struct ktermios *old_termios)
462 {
463 	struct usb_serial *serial = port->serial;
464 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
465 	struct pl2303_private *priv = usb_get_serial_port_data(port);
466 	unsigned long flags;
467 	unsigned char *buf;
468 	int ret;
469 	u8 control;
470 
471 	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
472 		return;
473 
474 	buf = kzalloc(7, GFP_KERNEL);
475 	if (!buf) {
476 		/* Report back no change occurred */
477 		if (old_termios)
478 			tty->termios = *old_termios;
479 		return;
480 	}
481 
482 	pl2303_get_line_request(port, buf);
483 
484 	switch (C_CSIZE(tty)) {
485 	case CS5:
486 		buf[6] = 5;
487 		break;
488 	case CS6:
489 		buf[6] = 6;
490 		break;
491 	case CS7:
492 		buf[6] = 7;
493 		break;
494 	default:
495 	case CS8:
496 		buf[6] = 8;
497 	}
498 	dev_dbg(&port->dev, "data bits = %d\n", buf[6]);
499 
500 	/* For reference buf[0]:buf[3] baud rate value */
501 	pl2303_encode_baud_rate(tty, port, &buf[0]);
502 
503 	/* For reference buf[4]=0 is 1 stop bits */
504 	/* For reference buf[4]=1 is 1.5 stop bits */
505 	/* For reference buf[4]=2 is 2 stop bits */
506 	if (C_CSTOPB(tty)) {
507 		/*
508 		 * NOTE: Comply with "real" UARTs / RS232:
509 		 *       use 1.5 instead of 2 stop bits with 5 data bits
510 		 */
511 		if (C_CSIZE(tty) == CS5) {
512 			buf[4] = 1;
513 			dev_dbg(&port->dev, "stop bits = 1.5\n");
514 		} else {
515 			buf[4] = 2;
516 			dev_dbg(&port->dev, "stop bits = 2\n");
517 		}
518 	} else {
519 		buf[4] = 0;
520 		dev_dbg(&port->dev, "stop bits = 1\n");
521 	}
522 
523 	if (C_PARENB(tty)) {
524 		/* For reference buf[5]=0 is none parity */
525 		/* For reference buf[5]=1 is odd parity */
526 		/* For reference buf[5]=2 is even parity */
527 		/* For reference buf[5]=3 is mark parity */
528 		/* For reference buf[5]=4 is space parity */
529 		if (C_PARODD(tty)) {
530 			if (C_CMSPAR(tty)) {
531 				buf[5] = 3;
532 				dev_dbg(&port->dev, "parity = mark\n");
533 			} else {
534 				buf[5] = 1;
535 				dev_dbg(&port->dev, "parity = odd\n");
536 			}
537 		} else {
538 			if (C_CMSPAR(tty)) {
539 				buf[5] = 4;
540 				dev_dbg(&port->dev, "parity = space\n");
541 			} else {
542 				buf[5] = 2;
543 				dev_dbg(&port->dev, "parity = even\n");
544 			}
545 		}
546 	} else {
547 		buf[5] = 0;
548 		dev_dbg(&port->dev, "parity = none\n");
549 	}
550 
551 	/*
552 	 * Some PL2303 are known to lose bytes if you change serial settings
553 	 * even to the same values as before. Thus we actually need to filter
554 	 * in this specific case.
555 	 *
556 	 * Note that the tty_termios_hw_change check above is not sufficient
557 	 * as a previously requested baud rate may differ from the one
558 	 * actually used (and stored in old_termios).
559 	 *
560 	 * NOTE: No additional locking needed for line_settings as it is
561 	 *       only used in set_termios, which is serialised against itself.
562 	 */
563 	if (!old_termios || memcmp(buf, priv->line_settings, 7)) {
564 		ret = pl2303_set_line_request(port, buf);
565 		if (!ret)
566 			memcpy(priv->line_settings, buf, 7);
567 	}
568 
569 	/* change control lines if we are switching to or from B0 */
570 	spin_lock_irqsave(&priv->lock, flags);
571 	control = priv->line_control;
572 	if (C_BAUD(tty) == B0)
573 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
574 	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
575 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
576 	if (control != priv->line_control) {
577 		control = priv->line_control;
578 		spin_unlock_irqrestore(&priv->lock, flags);
579 		pl2303_set_control_lines(port, control);
580 	} else {
581 		spin_unlock_irqrestore(&priv->lock, flags);
582 	}
583 
584 	if (C_CRTSCTS(tty)) {
585 		if (spriv->quirks & PL2303_QUIRK_LEGACY)
586 			pl2303_vendor_write(serial, 0x0, 0x41);
587 		else
588 			pl2303_vendor_write(serial, 0x0, 0x61);
589 	} else {
590 		pl2303_vendor_write(serial, 0x0, 0x0);
591 	}
592 
593 	kfree(buf);
594 }
595 
596 static void pl2303_dtr_rts(struct usb_serial_port *port, int on)
597 {
598 	struct pl2303_private *priv = usb_get_serial_port_data(port);
599 	unsigned long flags;
600 	u8 control;
601 
602 	spin_lock_irqsave(&priv->lock, flags);
603 	if (on)
604 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
605 	else
606 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
607 	control = priv->line_control;
608 	spin_unlock_irqrestore(&priv->lock, flags);
609 
610 	pl2303_set_control_lines(port, control);
611 }
612 
613 static void pl2303_close(struct usb_serial_port *port)
614 {
615 	usb_serial_generic_close(port);
616 	usb_kill_urb(port->interrupt_in_urb);
617 }
618 
619 static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
620 {
621 	struct usb_serial *serial = port->serial;
622 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
623 	int result;
624 
625 	if (spriv->quirks & PL2303_QUIRK_LEGACY) {
626 		usb_clear_halt(serial->dev, port->write_urb->pipe);
627 		usb_clear_halt(serial->dev, port->read_urb->pipe);
628 	} else {
629 		/* reset upstream data pipes */
630 		pl2303_vendor_write(serial, 8, 0);
631 		pl2303_vendor_write(serial, 9, 0);
632 	}
633 
634 	/* Setup termios */
635 	if (tty)
636 		pl2303_set_termios(tty, port, NULL);
637 
638 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
639 	if (result) {
640 		dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
641 			result);
642 		return result;
643 	}
644 
645 	result = usb_serial_generic_open(tty, port);
646 	if (result) {
647 		usb_kill_urb(port->interrupt_in_urb);
648 		return result;
649 	}
650 
651 	return 0;
652 }
653 
654 static int pl2303_tiocmset(struct tty_struct *tty,
655 			   unsigned int set, unsigned int clear)
656 {
657 	struct usb_serial_port *port = tty->driver_data;
658 	struct pl2303_private *priv = usb_get_serial_port_data(port);
659 	unsigned long flags;
660 	u8 control;
661 	int ret;
662 
663 	spin_lock_irqsave(&priv->lock, flags);
664 	if (set & TIOCM_RTS)
665 		priv->line_control |= CONTROL_RTS;
666 	if (set & TIOCM_DTR)
667 		priv->line_control |= CONTROL_DTR;
668 	if (clear & TIOCM_RTS)
669 		priv->line_control &= ~CONTROL_RTS;
670 	if (clear & TIOCM_DTR)
671 		priv->line_control &= ~CONTROL_DTR;
672 	control = priv->line_control;
673 	spin_unlock_irqrestore(&priv->lock, flags);
674 
675 	ret = pl2303_set_control_lines(port, control);
676 	if (ret)
677 		return usb_translate_errors(ret);
678 
679 	return 0;
680 }
681 
682 static int pl2303_tiocmget(struct tty_struct *tty)
683 {
684 	struct usb_serial_port *port = tty->driver_data;
685 	struct pl2303_private *priv = usb_get_serial_port_data(port);
686 	unsigned long flags;
687 	unsigned int mcr;
688 	unsigned int status;
689 	unsigned int result;
690 
691 	spin_lock_irqsave(&priv->lock, flags);
692 	mcr = priv->line_control;
693 	status = priv->line_status;
694 	spin_unlock_irqrestore(&priv->lock, flags);
695 
696 	result = ((mcr & CONTROL_DTR)		? TIOCM_DTR : 0)
697 		  | ((mcr & CONTROL_RTS)	? TIOCM_RTS : 0)
698 		  | ((status & UART_CTS)	? TIOCM_CTS : 0)
699 		  | ((status & UART_DSR)	? TIOCM_DSR : 0)
700 		  | ((status & UART_RING)	? TIOCM_RI  : 0)
701 		  | ((status & UART_DCD)	? TIOCM_CD  : 0);
702 
703 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
704 
705 	return result;
706 }
707 
708 static int pl2303_carrier_raised(struct usb_serial_port *port)
709 {
710 	struct pl2303_private *priv = usb_get_serial_port_data(port);
711 
712 	if (priv->line_status & UART_DCD)
713 		return 1;
714 
715 	return 0;
716 }
717 
718 static int pl2303_ioctl(struct tty_struct *tty,
719 			unsigned int cmd, unsigned long arg)
720 {
721 	struct serial_struct ser;
722 	struct usb_serial_port *port = tty->driver_data;
723 
724 	switch (cmd) {
725 	case TIOCGSERIAL:
726 		memset(&ser, 0, sizeof ser);
727 		ser.type = PORT_16654;
728 		ser.line = port->minor;
729 		ser.port = port->port_number;
730 		ser.baud_base = 460800;
731 
732 		if (copy_to_user((void __user *)arg, &ser, sizeof ser))
733 			return -EFAULT;
734 
735 		return 0;
736 	default:
737 		break;
738 	}
739 
740 	return -ENOIOCTLCMD;
741 }
742 
743 static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
744 {
745 	struct usb_serial_port *port = tty->driver_data;
746 	struct usb_serial *serial = port->serial;
747 	u16 state;
748 	int result;
749 
750 	if (break_state == 0)
751 		state = BREAK_OFF;
752 	else
753 		state = BREAK_ON;
754 
755 	dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
756 			state == BREAK_OFF ? "off" : "on");
757 
758 	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
759 				 BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
760 				 0, NULL, 0, 100);
761 	if (result)
762 		dev_err(&port->dev, "error sending break = %d\n", result);
763 }
764 
765 static void pl2303_update_line_status(struct usb_serial_port *port,
766 				      unsigned char *data,
767 				      unsigned int actual_length)
768 {
769 	struct usb_serial *serial = port->serial;
770 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
771 	struct pl2303_private *priv = usb_get_serial_port_data(port);
772 	struct tty_struct *tty;
773 	unsigned long flags;
774 	unsigned int status_idx = UART_STATE_INDEX;
775 	u8 status;
776 	u8 delta;
777 
778 	if (spriv->quirks & PL2303_QUIRK_UART_STATE_IDX0)
779 		status_idx = 0;
780 
781 	if (actual_length < status_idx + 1)
782 		return;
783 
784 	status = data[status_idx];
785 
786 	/* Save off the uart status for others to look at */
787 	spin_lock_irqsave(&priv->lock, flags);
788 	delta = priv->line_status ^ status;
789 	priv->line_status = status;
790 	spin_unlock_irqrestore(&priv->lock, flags);
791 
792 	if (status & UART_BREAK_ERROR)
793 		usb_serial_handle_break(port);
794 
795 	if (delta & UART_STATE_MSR_MASK) {
796 		if (delta & UART_CTS)
797 			port->icount.cts++;
798 		if (delta & UART_DSR)
799 			port->icount.dsr++;
800 		if (delta & UART_RING)
801 			port->icount.rng++;
802 		if (delta & UART_DCD) {
803 			port->icount.dcd++;
804 			tty = tty_port_tty_get(&port->port);
805 			if (tty) {
806 				usb_serial_handle_dcd_change(port, tty,
807 							status & UART_DCD);
808 				tty_kref_put(tty);
809 			}
810 		}
811 
812 		wake_up_interruptible(&port->port.delta_msr_wait);
813 	}
814 }
815 
816 static void pl2303_read_int_callback(struct urb *urb)
817 {
818 	struct usb_serial_port *port =  urb->context;
819 	unsigned char *data = urb->transfer_buffer;
820 	unsigned int actual_length = urb->actual_length;
821 	int status = urb->status;
822 	int retval;
823 
824 	switch (status) {
825 	case 0:
826 		/* success */
827 		break;
828 	case -ECONNRESET:
829 	case -ENOENT:
830 	case -ESHUTDOWN:
831 		/* this urb is terminated, clean up */
832 		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
833 			__func__, status);
834 		return;
835 	default:
836 		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
837 			__func__, status);
838 		goto exit;
839 	}
840 
841 	usb_serial_debug_data(&port->dev, __func__,
842 			      urb->actual_length, urb->transfer_buffer);
843 
844 	pl2303_update_line_status(port, data, actual_length);
845 
846 exit:
847 	retval = usb_submit_urb(urb, GFP_ATOMIC);
848 	if (retval) {
849 		dev_err(&port->dev,
850 			"%s - usb_submit_urb failed with result %d\n",
851 			__func__, retval);
852 	}
853 }
854 
855 static void pl2303_process_read_urb(struct urb *urb)
856 {
857 	struct usb_serial_port *port = urb->context;
858 	struct pl2303_private *priv = usb_get_serial_port_data(port);
859 	unsigned char *data = urb->transfer_buffer;
860 	char tty_flag = TTY_NORMAL;
861 	unsigned long flags;
862 	u8 line_status;
863 	int i;
864 
865 	/* update line status */
866 	spin_lock_irqsave(&priv->lock, flags);
867 	line_status = priv->line_status;
868 	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
869 	spin_unlock_irqrestore(&priv->lock, flags);
870 
871 	if (!urb->actual_length)
872 		return;
873 
874 	/*
875 	 * Break takes precedence over parity, which takes precedence over
876 	 * framing errors.
877 	 */
878 	if (line_status & UART_BREAK_ERROR)
879 		tty_flag = TTY_BREAK;
880 	else if (line_status & UART_PARITY_ERROR)
881 		tty_flag = TTY_PARITY;
882 	else if (line_status & UART_FRAME_ERROR)
883 		tty_flag = TTY_FRAME;
884 
885 	if (tty_flag != TTY_NORMAL)
886 		dev_dbg(&port->dev, "%s - tty_flag = %d\n", __func__,
887 								tty_flag);
888 	/* overrun is special, not associated with a char */
889 	if (line_status & UART_OVERRUN_ERROR)
890 		tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
891 
892 	if (port->port.console && port->sysrq) {
893 		for (i = 0; i < urb->actual_length; ++i)
894 			if (!usb_serial_handle_sysrq_char(port, data[i]))
895 				tty_insert_flip_char(&port->port, data[i],
896 						tty_flag);
897 	} else {
898 		tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
899 							urb->actual_length);
900 	}
901 
902 	tty_flip_buffer_push(&port->port);
903 }
904 
905 static struct usb_serial_driver pl2303_device = {
906 	.driver = {
907 		.owner =	THIS_MODULE,
908 		.name =		"pl2303",
909 	},
910 	.id_table =		id_table,
911 	.num_ports =		1,
912 	.bulk_in_size =		256,
913 	.bulk_out_size =	256,
914 	.open =			pl2303_open,
915 	.close =		pl2303_close,
916 	.dtr_rts =		pl2303_dtr_rts,
917 	.carrier_raised =	pl2303_carrier_raised,
918 	.ioctl =		pl2303_ioctl,
919 	.break_ctl =		pl2303_break_ctl,
920 	.set_termios =		pl2303_set_termios,
921 	.tiocmget =		pl2303_tiocmget,
922 	.tiocmset =		pl2303_tiocmset,
923 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
924 	.process_read_urb =	pl2303_process_read_urb,
925 	.read_int_callback =	pl2303_read_int_callback,
926 	.probe =		pl2303_probe,
927 	.attach =		pl2303_startup,
928 	.release =		pl2303_release,
929 	.port_probe =		pl2303_port_probe,
930 	.port_remove =		pl2303_port_remove,
931 };
932 
933 static struct usb_serial_driver * const serial_drivers[] = {
934 	&pl2303_device, NULL
935 };
936 
937 module_usb_serial_driver(serial_drivers, id_table);
938 
939 MODULE_DESCRIPTION("Prolific PL2303 USB to serial adaptor driver");
940 MODULE_LICENSE("GPL");
941