xref: /openbmc/linux/drivers/usb/serial/pl2303.c (revision 4f3db074)
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 static void pl2303_set_break(struct usb_serial_port *port, bool enable);
136 
137 enum pl2303_type {
138 	TYPE_01,	/* Type 0 and 1 (difference unknown) */
139 	TYPE_HX,	/* HX version of the pl2303 chip */
140 	TYPE_COUNT
141 };
142 
143 struct pl2303_type_data {
144 	speed_t max_baud_rate;
145 	unsigned long quirks;
146 };
147 
148 struct pl2303_serial_private {
149 	const struct pl2303_type_data *type;
150 	unsigned long quirks;
151 };
152 
153 struct pl2303_private {
154 	spinlock_t lock;
155 	u8 line_control;
156 	u8 line_status;
157 
158 	u8 line_settings[7];
159 };
160 
161 static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
162 	[TYPE_01] = {
163 		.max_baud_rate =	1228800,
164 		.quirks =		PL2303_QUIRK_LEGACY,
165 	},
166 	[TYPE_HX] = {
167 		.max_baud_rate =	12000000,
168 	},
169 };
170 
171 static int pl2303_vendor_read(struct usb_serial *serial, u16 value,
172 							unsigned char buf[1])
173 {
174 	struct device *dev = &serial->interface->dev;
175 	int res;
176 
177 	res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
178 			VENDOR_READ_REQUEST, VENDOR_READ_REQUEST_TYPE,
179 			value, 0, buf, 1, 100);
180 	if (res != 1) {
181 		dev_err(dev, "%s - failed to read [%04x]: %d\n", __func__,
182 								value, res);
183 		if (res >= 0)
184 			res = -EIO;
185 
186 		return res;
187 	}
188 
189 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, buf[0]);
190 
191 	return 0;
192 }
193 
194 static int pl2303_vendor_write(struct usb_serial *serial, u16 value, u16 index)
195 {
196 	struct device *dev = &serial->interface->dev;
197 	int res;
198 
199 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, index);
200 
201 	res = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
202 			VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
203 			value, index, NULL, 0, 100);
204 	if (res) {
205 		dev_err(dev, "%s - failed to write [%04x]: %d\n", __func__,
206 								value, res);
207 		return res;
208 	}
209 
210 	return 0;
211 }
212 
213 static int pl2303_probe(struct usb_serial *serial,
214 					const struct usb_device_id *id)
215 {
216 	usb_set_serial_data(serial, (void *)id->driver_info);
217 
218 	return 0;
219 }
220 
221 static int pl2303_startup(struct usb_serial *serial)
222 {
223 	struct pl2303_serial_private *spriv;
224 	enum pl2303_type type = TYPE_01;
225 	unsigned char *buf;
226 
227 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
228 	if (!spriv)
229 		return -ENOMEM;
230 
231 	buf = kmalloc(1, GFP_KERNEL);
232 	if (!buf) {
233 		kfree(spriv);
234 		return -ENOMEM;
235 	}
236 
237 	if (serial->dev->descriptor.bDeviceClass == 0x02)
238 		type = TYPE_01;		/* type 0 */
239 	else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40)
240 		type = TYPE_HX;
241 	else if (serial->dev->descriptor.bDeviceClass == 0x00)
242 		type = TYPE_01;		/* type 1 */
243 	else if (serial->dev->descriptor.bDeviceClass == 0xFF)
244 		type = TYPE_01;		/* type 1 */
245 	dev_dbg(&serial->interface->dev, "device type: %d\n", type);
246 
247 	spriv->type = &pl2303_type_data[type];
248 	spriv->quirks = (unsigned long)usb_get_serial_data(serial);
249 	spriv->quirks |= spriv->type->quirks;
250 
251 	usb_set_serial_data(serial, spriv);
252 
253 	pl2303_vendor_read(serial, 0x8484, buf);
254 	pl2303_vendor_write(serial, 0x0404, 0);
255 	pl2303_vendor_read(serial, 0x8484, buf);
256 	pl2303_vendor_read(serial, 0x8383, buf);
257 	pl2303_vendor_read(serial, 0x8484, buf);
258 	pl2303_vendor_write(serial, 0x0404, 1);
259 	pl2303_vendor_read(serial, 0x8484, buf);
260 	pl2303_vendor_read(serial, 0x8383, buf);
261 	pl2303_vendor_write(serial, 0, 1);
262 	pl2303_vendor_write(serial, 1, 0);
263 	if (spriv->quirks & PL2303_QUIRK_LEGACY)
264 		pl2303_vendor_write(serial, 2, 0x24);
265 	else
266 		pl2303_vendor_write(serial, 2, 0x44);
267 
268 	kfree(buf);
269 
270 	return 0;
271 }
272 
273 static void pl2303_release(struct usb_serial *serial)
274 {
275 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
276 
277 	kfree(spriv);
278 }
279 
280 static int pl2303_port_probe(struct usb_serial_port *port)
281 {
282 	struct pl2303_private *priv;
283 
284 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
285 	if (!priv)
286 		return -ENOMEM;
287 
288 	spin_lock_init(&priv->lock);
289 
290 	usb_set_serial_port_data(port, priv);
291 
292 	port->port.drain_delay = 256;
293 
294 	return 0;
295 }
296 
297 static int pl2303_port_remove(struct usb_serial_port *port)
298 {
299 	struct pl2303_private *priv = usb_get_serial_port_data(port);
300 
301 	kfree(priv);
302 
303 	return 0;
304 }
305 
306 static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value)
307 {
308 	struct usb_device *dev = port->serial->dev;
309 	int retval;
310 
311 	dev_dbg(&port->dev, "%s - %02x\n", __func__, value);
312 
313 	retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
314 				 SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE,
315 				 value, 0, NULL, 0, 100);
316 	if (retval)
317 		dev_err(&port->dev, "%s - failed: %d\n", __func__, retval);
318 
319 	return retval;
320 }
321 
322 /*
323  * Returns the nearest supported baud rate that can be set directly without
324  * using divisors.
325  */
326 static speed_t pl2303_get_supported_baud_rate(speed_t baud)
327 {
328 	static const speed_t baud_sup[] = {
329 		75, 150, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200, 9600,
330 		14400, 19200, 28800, 38400, 57600, 115200, 230400, 460800,
331 		614400, 921600, 1228800, 2457600, 3000000, 6000000
332 	};
333 
334 	unsigned i;
335 
336 	for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
337 		if (baud_sup[i] > baud)
338 			break;
339 	}
340 
341 	if (i == ARRAY_SIZE(baud_sup))
342 		baud = baud_sup[i - 1];
343 	else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
344 		baud = baud_sup[i - 1];
345 	else
346 		baud = baud_sup[i];
347 
348 	return baud;
349 }
350 
351 /*
352  * NOTE: If unsupported baud rates are set directly, the PL2303 seems to
353  *       use 9600 baud.
354  */
355 static speed_t pl2303_encode_baud_rate_direct(unsigned char buf[4],
356 								speed_t baud)
357 {
358 	put_unaligned_le32(baud, buf);
359 
360 	return baud;
361 }
362 
363 static speed_t pl2303_encode_baud_rate_divisor(unsigned char buf[4],
364 								speed_t baud)
365 {
366 	unsigned int tmp;
367 
368 	/*
369 	 * Apparently the formula is:
370 	 * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
371 	 */
372 	tmp = 12000000 * 32 / baud;
373 	buf[3] = 0x80;
374 	buf[2] = 0;
375 	buf[1] = (tmp >= 256);
376 	while (tmp >= 256) {
377 		tmp >>= 2;
378 		buf[1] <<= 1;
379 	}
380 	buf[0] = tmp;
381 
382 	return baud;
383 }
384 
385 static void pl2303_encode_baud_rate(struct tty_struct *tty,
386 					struct usb_serial_port *port,
387 					u8 buf[4])
388 {
389 	struct usb_serial *serial = port->serial;
390 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
391 	speed_t	baud_sup;
392 	speed_t baud;
393 
394 	baud = tty_get_baud_rate(tty);
395 	dev_dbg(&port->dev, "baud requested = %u\n", baud);
396 	if (!baud)
397 		return;
398 
399 	if (spriv->type->max_baud_rate)
400 		baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
401 	/*
402 	 * Use direct method for supported baud rates, otherwise use divisors.
403 	 */
404 	baud_sup = pl2303_get_supported_baud_rate(baud);
405 
406 	if (baud == baud_sup)
407 		baud = pl2303_encode_baud_rate_direct(buf, baud);
408 	else
409 		baud = pl2303_encode_baud_rate_divisor(buf, baud);
410 
411 	/* Save resulting baud rate */
412 	tty_encode_baud_rate(tty, baud, baud);
413 	dev_dbg(&port->dev, "baud set = %u\n", baud);
414 }
415 
416 static int pl2303_get_line_request(struct usb_serial_port *port,
417 							unsigned char buf[7])
418 {
419 	struct usb_device *udev = port->serial->dev;
420 	int ret;
421 
422 	ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
423 				GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
424 				0, 0, buf, 7, 100);
425 	if (ret != 7) {
426 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
427 
428 		if (ret > 0)
429 			ret = -EIO;
430 
431 		return ret;
432 	}
433 
434 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
435 
436 	return 0;
437 }
438 
439 static int pl2303_set_line_request(struct usb_serial_port *port,
440 							unsigned char buf[7])
441 {
442 	struct usb_device *udev = port->serial->dev;
443 	int ret;
444 
445 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
446 				SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
447 				0, 0, buf, 7, 100);
448 	if (ret != 7) {
449 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
450 
451 		if (ret > 0)
452 			ret = -EIO;
453 
454 		return ret;
455 	}
456 
457 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
458 
459 	return 0;
460 }
461 
462 static void pl2303_set_termios(struct tty_struct *tty,
463 		struct usb_serial_port *port, struct ktermios *old_termios)
464 {
465 	struct usb_serial *serial = port->serial;
466 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
467 	struct pl2303_private *priv = usb_get_serial_port_data(port);
468 	unsigned long flags;
469 	unsigned char *buf;
470 	int ret;
471 	u8 control;
472 
473 	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
474 		return;
475 
476 	buf = kzalloc(7, GFP_KERNEL);
477 	if (!buf) {
478 		/* Report back no change occurred */
479 		if (old_termios)
480 			tty->termios = *old_termios;
481 		return;
482 	}
483 
484 	pl2303_get_line_request(port, buf);
485 
486 	switch (C_CSIZE(tty)) {
487 	case CS5:
488 		buf[6] = 5;
489 		break;
490 	case CS6:
491 		buf[6] = 6;
492 		break;
493 	case CS7:
494 		buf[6] = 7;
495 		break;
496 	default:
497 	case CS8:
498 		buf[6] = 8;
499 	}
500 	dev_dbg(&port->dev, "data bits = %d\n", buf[6]);
501 
502 	/* For reference buf[0]:buf[3] baud rate value */
503 	pl2303_encode_baud_rate(tty, port, &buf[0]);
504 
505 	/* For reference buf[4]=0 is 1 stop bits */
506 	/* For reference buf[4]=1 is 1.5 stop bits */
507 	/* For reference buf[4]=2 is 2 stop bits */
508 	if (C_CSTOPB(tty)) {
509 		/*
510 		 * NOTE: Comply with "real" UARTs / RS232:
511 		 *       use 1.5 instead of 2 stop bits with 5 data bits
512 		 */
513 		if (C_CSIZE(tty) == CS5) {
514 			buf[4] = 1;
515 			dev_dbg(&port->dev, "stop bits = 1.5\n");
516 		} else {
517 			buf[4] = 2;
518 			dev_dbg(&port->dev, "stop bits = 2\n");
519 		}
520 	} else {
521 		buf[4] = 0;
522 		dev_dbg(&port->dev, "stop bits = 1\n");
523 	}
524 
525 	if (C_PARENB(tty)) {
526 		/* For reference buf[5]=0 is none parity */
527 		/* For reference buf[5]=1 is odd parity */
528 		/* For reference buf[5]=2 is even parity */
529 		/* For reference buf[5]=3 is mark parity */
530 		/* For reference buf[5]=4 is space parity */
531 		if (C_PARODD(tty)) {
532 			if (C_CMSPAR(tty)) {
533 				buf[5] = 3;
534 				dev_dbg(&port->dev, "parity = mark\n");
535 			} else {
536 				buf[5] = 1;
537 				dev_dbg(&port->dev, "parity = odd\n");
538 			}
539 		} else {
540 			if (C_CMSPAR(tty)) {
541 				buf[5] = 4;
542 				dev_dbg(&port->dev, "parity = space\n");
543 			} else {
544 				buf[5] = 2;
545 				dev_dbg(&port->dev, "parity = even\n");
546 			}
547 		}
548 	} else {
549 		buf[5] = 0;
550 		dev_dbg(&port->dev, "parity = none\n");
551 	}
552 
553 	/*
554 	 * Some PL2303 are known to lose bytes if you change serial settings
555 	 * even to the same values as before. Thus we actually need to filter
556 	 * in this specific case.
557 	 *
558 	 * Note that the tty_termios_hw_change check above is not sufficient
559 	 * as a previously requested baud rate may differ from the one
560 	 * actually used (and stored in old_termios).
561 	 *
562 	 * NOTE: No additional locking needed for line_settings as it is
563 	 *       only used in set_termios, which is serialised against itself.
564 	 */
565 	if (!old_termios || memcmp(buf, priv->line_settings, 7)) {
566 		ret = pl2303_set_line_request(port, buf);
567 		if (!ret)
568 			memcpy(priv->line_settings, buf, 7);
569 	}
570 
571 	/* change control lines if we are switching to or from B0 */
572 	spin_lock_irqsave(&priv->lock, flags);
573 	control = priv->line_control;
574 	if (C_BAUD(tty) == B0)
575 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
576 	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
577 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
578 	if (control != priv->line_control) {
579 		control = priv->line_control;
580 		spin_unlock_irqrestore(&priv->lock, flags);
581 		pl2303_set_control_lines(port, control);
582 	} else {
583 		spin_unlock_irqrestore(&priv->lock, flags);
584 	}
585 
586 	if (C_CRTSCTS(tty)) {
587 		if (spriv->quirks & PL2303_QUIRK_LEGACY)
588 			pl2303_vendor_write(serial, 0x0, 0x41);
589 		else
590 			pl2303_vendor_write(serial, 0x0, 0x61);
591 	} else {
592 		pl2303_vendor_write(serial, 0x0, 0x0);
593 	}
594 
595 	kfree(buf);
596 }
597 
598 static void pl2303_dtr_rts(struct usb_serial_port *port, int on)
599 {
600 	struct pl2303_private *priv = usb_get_serial_port_data(port);
601 	unsigned long flags;
602 	u8 control;
603 
604 	spin_lock_irqsave(&priv->lock, flags);
605 	if (on)
606 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
607 	else
608 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
609 	control = priv->line_control;
610 	spin_unlock_irqrestore(&priv->lock, flags);
611 
612 	pl2303_set_control_lines(port, control);
613 }
614 
615 static void pl2303_close(struct usb_serial_port *port)
616 {
617 	usb_serial_generic_close(port);
618 	usb_kill_urb(port->interrupt_in_urb);
619 	pl2303_set_break(port, false);
620 }
621 
622 static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
623 {
624 	struct usb_serial *serial = port->serial;
625 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
626 	int result;
627 
628 	if (spriv->quirks & PL2303_QUIRK_LEGACY) {
629 		usb_clear_halt(serial->dev, port->write_urb->pipe);
630 		usb_clear_halt(serial->dev, port->read_urb->pipe);
631 	} else {
632 		/* reset upstream data pipes */
633 		pl2303_vendor_write(serial, 8, 0);
634 		pl2303_vendor_write(serial, 9, 0);
635 	}
636 
637 	/* Setup termios */
638 	if (tty)
639 		pl2303_set_termios(tty, port, NULL);
640 
641 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
642 	if (result) {
643 		dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
644 			result);
645 		return result;
646 	}
647 
648 	result = usb_serial_generic_open(tty, port);
649 	if (result) {
650 		usb_kill_urb(port->interrupt_in_urb);
651 		return result;
652 	}
653 
654 	return 0;
655 }
656 
657 static int pl2303_tiocmset(struct tty_struct *tty,
658 			   unsigned int set, unsigned int clear)
659 {
660 	struct usb_serial_port *port = tty->driver_data;
661 	struct pl2303_private *priv = usb_get_serial_port_data(port);
662 	unsigned long flags;
663 	u8 control;
664 	int ret;
665 
666 	spin_lock_irqsave(&priv->lock, flags);
667 	if (set & TIOCM_RTS)
668 		priv->line_control |= CONTROL_RTS;
669 	if (set & TIOCM_DTR)
670 		priv->line_control |= CONTROL_DTR;
671 	if (clear & TIOCM_RTS)
672 		priv->line_control &= ~CONTROL_RTS;
673 	if (clear & TIOCM_DTR)
674 		priv->line_control &= ~CONTROL_DTR;
675 	control = priv->line_control;
676 	spin_unlock_irqrestore(&priv->lock, flags);
677 
678 	ret = pl2303_set_control_lines(port, control);
679 	if (ret)
680 		return usb_translate_errors(ret);
681 
682 	return 0;
683 }
684 
685 static int pl2303_tiocmget(struct tty_struct *tty)
686 {
687 	struct usb_serial_port *port = tty->driver_data;
688 	struct pl2303_private *priv = usb_get_serial_port_data(port);
689 	unsigned long flags;
690 	unsigned int mcr;
691 	unsigned int status;
692 	unsigned int result;
693 
694 	spin_lock_irqsave(&priv->lock, flags);
695 	mcr = priv->line_control;
696 	status = priv->line_status;
697 	spin_unlock_irqrestore(&priv->lock, flags);
698 
699 	result = ((mcr & CONTROL_DTR)		? TIOCM_DTR : 0)
700 		  | ((mcr & CONTROL_RTS)	? TIOCM_RTS : 0)
701 		  | ((status & UART_CTS)	? TIOCM_CTS : 0)
702 		  | ((status & UART_DSR)	? TIOCM_DSR : 0)
703 		  | ((status & UART_RING)	? TIOCM_RI  : 0)
704 		  | ((status & UART_DCD)	? TIOCM_CD  : 0);
705 
706 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
707 
708 	return result;
709 }
710 
711 static int pl2303_carrier_raised(struct usb_serial_port *port)
712 {
713 	struct pl2303_private *priv = usb_get_serial_port_data(port);
714 
715 	if (priv->line_status & UART_DCD)
716 		return 1;
717 
718 	return 0;
719 }
720 
721 static int pl2303_ioctl(struct tty_struct *tty,
722 			unsigned int cmd, unsigned long arg)
723 {
724 	struct serial_struct ser;
725 	struct usb_serial_port *port = tty->driver_data;
726 
727 	switch (cmd) {
728 	case TIOCGSERIAL:
729 		memset(&ser, 0, sizeof ser);
730 		ser.type = PORT_16654;
731 		ser.line = port->minor;
732 		ser.port = port->port_number;
733 		ser.baud_base = 460800;
734 
735 		if (copy_to_user((void __user *)arg, &ser, sizeof ser))
736 			return -EFAULT;
737 
738 		return 0;
739 	default:
740 		break;
741 	}
742 
743 	return -ENOIOCTLCMD;
744 }
745 
746 static void pl2303_set_break(struct usb_serial_port *port, bool enable)
747 {
748 	struct usb_serial *serial = port->serial;
749 	u16 state;
750 	int result;
751 
752 	if (enable)
753 		state = BREAK_ON;
754 	else
755 		state = BREAK_OFF;
756 
757 	dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
758 			state == BREAK_OFF ? "off" : "on");
759 
760 	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
761 				 BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
762 				 0, NULL, 0, 100);
763 	if (result)
764 		dev_err(&port->dev, "error sending break = %d\n", result);
765 }
766 
767 static void pl2303_break_ctl(struct tty_struct *tty, int state)
768 {
769 	struct usb_serial_port *port = tty->driver_data;
770 
771 	pl2303_set_break(port, state);
772 }
773 
774 static void pl2303_update_line_status(struct usb_serial_port *port,
775 				      unsigned char *data,
776 				      unsigned int actual_length)
777 {
778 	struct usb_serial *serial = port->serial;
779 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
780 	struct pl2303_private *priv = usb_get_serial_port_data(port);
781 	struct tty_struct *tty;
782 	unsigned long flags;
783 	unsigned int status_idx = UART_STATE_INDEX;
784 	u8 status;
785 	u8 delta;
786 
787 	if (spriv->quirks & PL2303_QUIRK_UART_STATE_IDX0)
788 		status_idx = 0;
789 
790 	if (actual_length < status_idx + 1)
791 		return;
792 
793 	status = data[status_idx];
794 
795 	/* Save off the uart status for others to look at */
796 	spin_lock_irqsave(&priv->lock, flags);
797 	delta = priv->line_status ^ status;
798 	priv->line_status = status;
799 	spin_unlock_irqrestore(&priv->lock, flags);
800 
801 	if (status & UART_BREAK_ERROR)
802 		usb_serial_handle_break(port);
803 
804 	if (delta & UART_STATE_MSR_MASK) {
805 		if (delta & UART_CTS)
806 			port->icount.cts++;
807 		if (delta & UART_DSR)
808 			port->icount.dsr++;
809 		if (delta & UART_RING)
810 			port->icount.rng++;
811 		if (delta & UART_DCD) {
812 			port->icount.dcd++;
813 			tty = tty_port_tty_get(&port->port);
814 			if (tty) {
815 				usb_serial_handle_dcd_change(port, tty,
816 							status & UART_DCD);
817 				tty_kref_put(tty);
818 			}
819 		}
820 
821 		wake_up_interruptible(&port->port.delta_msr_wait);
822 	}
823 }
824 
825 static void pl2303_read_int_callback(struct urb *urb)
826 {
827 	struct usb_serial_port *port =  urb->context;
828 	unsigned char *data = urb->transfer_buffer;
829 	unsigned int actual_length = urb->actual_length;
830 	int status = urb->status;
831 	int retval;
832 
833 	switch (status) {
834 	case 0:
835 		/* success */
836 		break;
837 	case -ECONNRESET:
838 	case -ENOENT:
839 	case -ESHUTDOWN:
840 		/* this urb is terminated, clean up */
841 		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
842 			__func__, status);
843 		return;
844 	default:
845 		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
846 			__func__, status);
847 		goto exit;
848 	}
849 
850 	usb_serial_debug_data(&port->dev, __func__,
851 			      urb->actual_length, urb->transfer_buffer);
852 
853 	pl2303_update_line_status(port, data, actual_length);
854 
855 exit:
856 	retval = usb_submit_urb(urb, GFP_ATOMIC);
857 	if (retval) {
858 		dev_err(&port->dev,
859 			"%s - usb_submit_urb failed with result %d\n",
860 			__func__, retval);
861 	}
862 }
863 
864 static void pl2303_process_read_urb(struct urb *urb)
865 {
866 	struct usb_serial_port *port = urb->context;
867 	struct pl2303_private *priv = usb_get_serial_port_data(port);
868 	unsigned char *data = urb->transfer_buffer;
869 	char tty_flag = TTY_NORMAL;
870 	unsigned long flags;
871 	u8 line_status;
872 	int i;
873 
874 	/* update line status */
875 	spin_lock_irqsave(&priv->lock, flags);
876 	line_status = priv->line_status;
877 	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
878 	spin_unlock_irqrestore(&priv->lock, flags);
879 
880 	if (!urb->actual_length)
881 		return;
882 
883 	/*
884 	 * Break takes precedence over parity, which takes precedence over
885 	 * framing errors.
886 	 */
887 	if (line_status & UART_BREAK_ERROR)
888 		tty_flag = TTY_BREAK;
889 	else if (line_status & UART_PARITY_ERROR)
890 		tty_flag = TTY_PARITY;
891 	else if (line_status & UART_FRAME_ERROR)
892 		tty_flag = TTY_FRAME;
893 
894 	if (tty_flag != TTY_NORMAL)
895 		dev_dbg(&port->dev, "%s - tty_flag = %d\n", __func__,
896 								tty_flag);
897 	/* overrun is special, not associated with a char */
898 	if (line_status & UART_OVERRUN_ERROR)
899 		tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
900 
901 	if (port->port.console && port->sysrq) {
902 		for (i = 0; i < urb->actual_length; ++i)
903 			if (!usb_serial_handle_sysrq_char(port, data[i]))
904 				tty_insert_flip_char(&port->port, data[i],
905 						tty_flag);
906 	} else {
907 		tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
908 							urb->actual_length);
909 	}
910 
911 	tty_flip_buffer_push(&port->port);
912 }
913 
914 static struct usb_serial_driver pl2303_device = {
915 	.driver = {
916 		.owner =	THIS_MODULE,
917 		.name =		"pl2303",
918 	},
919 	.id_table =		id_table,
920 	.num_ports =		1,
921 	.bulk_in_size =		256,
922 	.bulk_out_size =	256,
923 	.open =			pl2303_open,
924 	.close =		pl2303_close,
925 	.dtr_rts =		pl2303_dtr_rts,
926 	.carrier_raised =	pl2303_carrier_raised,
927 	.ioctl =		pl2303_ioctl,
928 	.break_ctl =		pl2303_break_ctl,
929 	.set_termios =		pl2303_set_termios,
930 	.tiocmget =		pl2303_tiocmget,
931 	.tiocmset =		pl2303_tiocmset,
932 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
933 	.process_read_urb =	pl2303_process_read_urb,
934 	.read_int_callback =	pl2303_read_int_callback,
935 	.probe =		pl2303_probe,
936 	.attach =		pl2303_startup,
937 	.release =		pl2303_release,
938 	.port_probe =		pl2303_port_probe,
939 	.port_remove =		pl2303_port_remove,
940 };
941 
942 static struct usb_serial_driver * const serial_drivers[] = {
943 	&pl2303_device, NULL
944 };
945 
946 module_usb_serial_driver(serial_drivers, id_table);
947 
948 MODULE_DESCRIPTION("Prolific PL2303 USB to serial adaptor driver");
949 MODULE_LICENSE("GPL");
950