xref: /openbmc/linux/drivers/usb/serial/pl2303.c (revision 206a81c1)
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(IODATA_VENDOR_ID, IODATA_PRODUCT_ID) },
49 	{ USB_DEVICE(IODATA_VENDOR_ID, IODATA_PRODUCT_ID_RSAQ5) },
50 	{ USB_DEVICE(ATEN_VENDOR_ID, ATEN_PRODUCT_ID) },
51 	{ USB_DEVICE(ATEN_VENDOR_ID2, ATEN_PRODUCT_ID) },
52 	{ USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID) },
53 	{ USB_DEVICE(ELCOM_VENDOR_ID, ELCOM_PRODUCT_ID_UCSGT) },
54 	{ USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID) },
55 	{ USB_DEVICE(ITEGNO_VENDOR_ID, ITEGNO_PRODUCT_ID_2080) },
56 	{ USB_DEVICE(MA620_VENDOR_ID, MA620_PRODUCT_ID) },
57 	{ USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID) },
58 	{ USB_DEVICE(TRIPP_VENDOR_ID, TRIPP_PRODUCT_ID) },
59 	{ USB_DEVICE(RADIOSHACK_VENDOR_ID, RADIOSHACK_PRODUCT_ID) },
60 	{ USB_DEVICE(DCU10_VENDOR_ID, DCU10_PRODUCT_ID) },
61 	{ USB_DEVICE(SITECOM_VENDOR_ID, SITECOM_PRODUCT_ID) },
62 	{ USB_DEVICE(ALCATEL_VENDOR_ID, ALCATEL_PRODUCT_ID) },
63 	{ USB_DEVICE(SAMSUNG_VENDOR_ID, SAMSUNG_PRODUCT_ID) },
64 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_SX1),
65 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
66 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X65),
67 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
68 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_X75),
69 		.driver_info = PL2303_QUIRK_UART_STATE_IDX0 },
70 	{ USB_DEVICE(SIEMENS_VENDOR_ID, SIEMENS_PRODUCT_ID_EF81) },
71 	{ USB_DEVICE(BENQ_VENDOR_ID, BENQ_PRODUCT_ID_S81) }, /* Benq/Siemens S81 */
72 	{ USB_DEVICE(SYNTECH_VENDOR_ID, SYNTECH_PRODUCT_ID) },
73 	{ USB_DEVICE(NOKIA_CA42_VENDOR_ID, NOKIA_CA42_PRODUCT_ID) },
74 	{ USB_DEVICE(CA_42_CA42_VENDOR_ID, CA_42_CA42_PRODUCT_ID) },
75 	{ USB_DEVICE(SAGEM_VENDOR_ID, SAGEM_PRODUCT_ID) },
76 	{ USB_DEVICE(LEADTEK_VENDOR_ID, LEADTEK_9531_PRODUCT_ID) },
77 	{ USB_DEVICE(SPEEDDRAGON_VENDOR_ID, SPEEDDRAGON_PRODUCT_ID) },
78 	{ USB_DEVICE(DATAPILOT_U2_VENDOR_ID, DATAPILOT_U2_PRODUCT_ID) },
79 	{ USB_DEVICE(BELKIN_VENDOR_ID, BELKIN_PRODUCT_ID) },
80 	{ USB_DEVICE(ALCOR_VENDOR_ID, ALCOR_PRODUCT_ID) },
81 	{ USB_DEVICE(WS002IN_VENDOR_ID, WS002IN_PRODUCT_ID) },
82 	{ USB_DEVICE(COREGA_VENDOR_ID, COREGA_PRODUCT_ID) },
83 	{ USB_DEVICE(YCCABLE_VENDOR_ID, YCCABLE_PRODUCT_ID) },
84 	{ USB_DEVICE(SUPERIAL_VENDOR_ID, SUPERIAL_PRODUCT_ID) },
85 	{ USB_DEVICE(HP_VENDOR_ID, HP_LD220_PRODUCT_ID) },
86 	{ USB_DEVICE(HP_VENDOR_ID, HP_LD960_PRODUCT_ID) },
87 	{ USB_DEVICE(HP_VENDOR_ID, HP_LCM220_PRODUCT_ID) },
88 	{ USB_DEVICE(HP_VENDOR_ID, HP_LCM960_PRODUCT_ID) },
89 	{ USB_DEVICE(CRESSI_VENDOR_ID, CRESSI_EDY_PRODUCT_ID) },
90 	{ USB_DEVICE(ZEAGLE_VENDOR_ID, ZEAGLE_N2ITION3_PRODUCT_ID) },
91 	{ USB_DEVICE(SONY_VENDOR_ID, SONY_QN3USB_PRODUCT_ID) },
92 	{ USB_DEVICE(SANWA_VENDOR_ID, SANWA_PRODUCT_ID) },
93 	{ USB_DEVICE(ADLINK_VENDOR_ID, ADLINK_ND6530_PRODUCT_ID) },
94 	{ USB_DEVICE(SMART_VENDOR_ID, SMART_PRODUCT_ID) },
95 	{ }					/* Terminating entry */
96 };
97 
98 MODULE_DEVICE_TABLE(usb, id_table);
99 
100 #define SET_LINE_REQUEST_TYPE		0x21
101 #define SET_LINE_REQUEST		0x20
102 
103 #define SET_CONTROL_REQUEST_TYPE	0x21
104 #define SET_CONTROL_REQUEST		0x22
105 #define CONTROL_DTR			0x01
106 #define CONTROL_RTS			0x02
107 
108 #define BREAK_REQUEST_TYPE		0x21
109 #define BREAK_REQUEST			0x23
110 #define BREAK_ON			0xffff
111 #define BREAK_OFF			0x0000
112 
113 #define GET_LINE_REQUEST_TYPE		0xa1
114 #define GET_LINE_REQUEST		0x21
115 
116 #define VENDOR_WRITE_REQUEST_TYPE	0x40
117 #define VENDOR_WRITE_REQUEST		0x01
118 
119 #define VENDOR_READ_REQUEST_TYPE	0xc0
120 #define VENDOR_READ_REQUEST		0x01
121 
122 #define UART_STATE_INDEX		8
123 #define UART_STATE_MSR_MASK		0x8b
124 #define UART_STATE_TRANSIENT_MASK	0x74
125 #define UART_DCD			0x01
126 #define UART_DSR			0x02
127 #define UART_BREAK_ERROR		0x04
128 #define UART_RING			0x08
129 #define UART_FRAME_ERROR		0x10
130 #define UART_PARITY_ERROR		0x20
131 #define UART_OVERRUN_ERROR		0x40
132 #define UART_CTS			0x80
133 
134 
135 enum pl2303_type {
136 	TYPE_01,	/* Type 0 and 1 (difference unknown) */
137 	TYPE_HX,	/* HX version of the pl2303 chip */
138 	TYPE_COUNT
139 };
140 
141 struct pl2303_type_data {
142 	speed_t max_baud_rate;
143 	unsigned long quirks;
144 };
145 
146 struct pl2303_serial_private {
147 	const struct pl2303_type_data *type;
148 	unsigned long quirks;
149 };
150 
151 struct pl2303_private {
152 	spinlock_t lock;
153 	u8 line_control;
154 	u8 line_status;
155 
156 	u8 line_settings[7];
157 };
158 
159 static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
160 	[TYPE_01] = {
161 		.max_baud_rate =	1228800,
162 		.quirks =		PL2303_QUIRK_LEGACY,
163 	},
164 };
165 
166 static int pl2303_vendor_read(struct usb_serial *serial, u16 value,
167 							unsigned char buf[1])
168 {
169 	struct device *dev = &serial->interface->dev;
170 	int res;
171 
172 	res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
173 			VENDOR_READ_REQUEST, VENDOR_READ_REQUEST_TYPE,
174 			value, 0, buf, 1, 100);
175 	if (res != 1) {
176 		dev_err(dev, "%s - failed to read [%04x]: %d\n", __func__,
177 								value, res);
178 		if (res >= 0)
179 			res = -EIO;
180 
181 		return res;
182 	}
183 
184 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, buf[0]);
185 
186 	return 0;
187 }
188 
189 static int pl2303_vendor_write(struct usb_serial *serial, u16 value, u16 index)
190 {
191 	struct device *dev = &serial->interface->dev;
192 	int res;
193 
194 	dev_dbg(dev, "%s - [%04x] = %02x\n", __func__, value, index);
195 
196 	res = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
197 			VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
198 			value, index, NULL, 0, 100);
199 	if (res) {
200 		dev_err(dev, "%s - failed to write [%04x]: %d\n", __func__,
201 								value, res);
202 		return res;
203 	}
204 
205 	return 0;
206 }
207 
208 static int pl2303_probe(struct usb_serial *serial,
209 					const struct usb_device_id *id)
210 {
211 	usb_set_serial_data(serial, (void *)id->driver_info);
212 
213 	return 0;
214 }
215 
216 static int pl2303_startup(struct usb_serial *serial)
217 {
218 	struct pl2303_serial_private *spriv;
219 	enum pl2303_type type = TYPE_01;
220 	unsigned char *buf;
221 
222 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
223 	if (!spriv)
224 		return -ENOMEM;
225 
226 	buf = kmalloc(1, GFP_KERNEL);
227 	if (!buf) {
228 		kfree(spriv);
229 		return -ENOMEM;
230 	}
231 
232 	if (serial->dev->descriptor.bDeviceClass == 0x02)
233 		type = TYPE_01;		/* type 0 */
234 	else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40)
235 		type = TYPE_HX;
236 	else if (serial->dev->descriptor.bDeviceClass == 0x00)
237 		type = TYPE_01;		/* type 1 */
238 	else if (serial->dev->descriptor.bDeviceClass == 0xFF)
239 		type = TYPE_01;		/* type 1 */
240 	dev_dbg(&serial->interface->dev, "device type: %d\n", type);
241 
242 	spriv->type = &pl2303_type_data[type];
243 	spriv->quirks = (unsigned long)usb_get_serial_data(serial);
244 	spriv->quirks |= spriv->type->quirks;
245 
246 	usb_set_serial_data(serial, spriv);
247 
248 	pl2303_vendor_read(serial, 0x8484, buf);
249 	pl2303_vendor_write(serial, 0x0404, 0);
250 	pl2303_vendor_read(serial, 0x8484, buf);
251 	pl2303_vendor_read(serial, 0x8383, buf);
252 	pl2303_vendor_read(serial, 0x8484, buf);
253 	pl2303_vendor_write(serial, 0x0404, 1);
254 	pl2303_vendor_read(serial, 0x8484, buf);
255 	pl2303_vendor_read(serial, 0x8383, buf);
256 	pl2303_vendor_write(serial, 0, 1);
257 	pl2303_vendor_write(serial, 1, 0);
258 	if (spriv->quirks & PL2303_QUIRK_LEGACY)
259 		pl2303_vendor_write(serial, 2, 0x24);
260 	else
261 		pl2303_vendor_write(serial, 2, 0x44);
262 
263 	kfree(buf);
264 
265 	return 0;
266 }
267 
268 static void pl2303_release(struct usb_serial *serial)
269 {
270 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
271 
272 	kfree(spriv);
273 }
274 
275 static int pl2303_port_probe(struct usb_serial_port *port)
276 {
277 	struct pl2303_private *priv;
278 
279 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
280 	if (!priv)
281 		return -ENOMEM;
282 
283 	spin_lock_init(&priv->lock);
284 
285 	usb_set_serial_port_data(port, priv);
286 
287 	port->port.drain_delay = 256;
288 
289 	return 0;
290 }
291 
292 static int pl2303_port_remove(struct usb_serial_port *port)
293 {
294 	struct pl2303_private *priv = usb_get_serial_port_data(port);
295 
296 	kfree(priv);
297 
298 	return 0;
299 }
300 
301 static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value)
302 {
303 	struct usb_device *dev = port->serial->dev;
304 	int retval;
305 
306 	dev_dbg(&port->dev, "%s - %02x\n", __func__, value);
307 
308 	retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
309 				 SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE,
310 				 value, 0, NULL, 0, 100);
311 	if (retval)
312 		dev_err(&port->dev, "%s - failed: %d\n", __func__, retval);
313 
314 	return retval;
315 }
316 
317 /*
318  * Returns the nearest supported baud rate that can be set directly without
319  * using divisors.
320  */
321 static speed_t pl2303_get_supported_baud_rate(speed_t baud)
322 {
323 	static const speed_t baud_sup[] = {
324 		75, 150, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200, 9600,
325 		14400, 19200, 28800, 38400, 57600, 115200, 230400, 460800,
326 		614400, 921600, 1228800, 2457600, 3000000, 6000000
327 	};
328 
329 	unsigned i;
330 
331 	for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
332 		if (baud_sup[i] > baud)
333 			break;
334 	}
335 
336 	if (i == ARRAY_SIZE(baud_sup))
337 		baud = baud_sup[i - 1];
338 	else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
339 		baud = baud_sup[i - 1];
340 	else
341 		baud = baud_sup[i];
342 
343 	return baud;
344 }
345 
346 /*
347  * NOTE: If unsupported baud rates are set directly, the PL2303 seems to
348  *       use 9600 baud.
349  */
350 static speed_t pl2303_encode_baud_rate_direct(unsigned char buf[4],
351 								speed_t baud)
352 {
353 	put_unaligned_le32(baud, buf);
354 
355 	return baud;
356 }
357 
358 static speed_t pl2303_encode_baud_rate_divisor(unsigned char buf[4],
359 								speed_t baud)
360 {
361 	unsigned int tmp;
362 
363 	/*
364 	 * Apparently the formula is:
365 	 * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
366 	 */
367 	tmp = 12000000 * 32 / baud;
368 	buf[3] = 0x80;
369 	buf[2] = 0;
370 	buf[1] = (tmp >= 256);
371 	while (tmp >= 256) {
372 		tmp >>= 2;
373 		buf[1] <<= 1;
374 	}
375 	buf[0] = tmp;
376 
377 	return baud;
378 }
379 
380 static void pl2303_encode_baud_rate(struct tty_struct *tty,
381 					struct usb_serial_port *port,
382 					u8 buf[4])
383 {
384 	struct usb_serial *serial = port->serial;
385 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
386 	speed_t	baud_sup;
387 	speed_t baud;
388 
389 	baud = tty_get_baud_rate(tty);
390 	dev_dbg(&port->dev, "baud requested = %u\n", baud);
391 	if (!baud)
392 		return;
393 
394 	if (spriv->type->max_baud_rate)
395 		baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
396 	/*
397 	 * Set baud rate to nearest supported value.
398 	 *
399 	 * NOTE: Baud rate 500k can only be set using divisors.
400 	 */
401 	baud_sup = pl2303_get_supported_baud_rate(baud);
402 
403 	if (baud == 500000)
404 		baud = pl2303_encode_baud_rate_divisor(buf, baud);
405 	else
406 		baud = pl2303_encode_baud_rate_direct(buf, baud_sup);
407 
408 	/* Save resulting baud rate */
409 	tty_encode_baud_rate(tty, baud, baud);
410 	dev_dbg(&port->dev, "baud set = %u\n", baud);
411 }
412 
413 static int pl2303_get_line_request(struct usb_serial_port *port,
414 							unsigned char buf[7])
415 {
416 	struct usb_device *udev = port->serial->dev;
417 	int ret;
418 
419 	ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
420 				GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
421 				0, 0, buf, 7, 100);
422 	if (ret != 7) {
423 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
424 
425 		if (ret > 0)
426 			ret = -EIO;
427 
428 		return ret;
429 	}
430 
431 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
432 
433 	return 0;
434 }
435 
436 static int pl2303_set_line_request(struct usb_serial_port *port,
437 							unsigned char buf[7])
438 {
439 	struct usb_device *udev = port->serial->dev;
440 	int ret;
441 
442 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
443 				SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
444 				0, 0, buf, 7, 100);
445 	if (ret != 7) {
446 		dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
447 
448 		if (ret > 0)
449 			ret = -EIO;
450 
451 		return ret;
452 	}
453 
454 	dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);
455 
456 	return 0;
457 }
458 
459 static void pl2303_set_termios(struct tty_struct *tty,
460 		struct usb_serial_port *port, struct ktermios *old_termios)
461 {
462 	struct usb_serial *serial = port->serial;
463 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
464 	struct pl2303_private *priv = usb_get_serial_port_data(port);
465 	unsigned long flags;
466 	unsigned char *buf;
467 	int ret;
468 	u8 control;
469 
470 	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
471 		return;
472 
473 	buf = kzalloc(7, GFP_KERNEL);
474 	if (!buf) {
475 		/* Report back no change occurred */
476 		if (old_termios)
477 			tty->termios = *old_termios;
478 		return;
479 	}
480 
481 	pl2303_get_line_request(port, buf);
482 
483 	switch (C_CSIZE(tty)) {
484 	case CS5:
485 		buf[6] = 5;
486 		break;
487 	case CS6:
488 		buf[6] = 6;
489 		break;
490 	case CS7:
491 		buf[6] = 7;
492 		break;
493 	default:
494 	case CS8:
495 		buf[6] = 8;
496 	}
497 	dev_dbg(&port->dev, "data bits = %d\n", buf[6]);
498 
499 	/* For reference buf[0]:buf[3] baud rate value */
500 	pl2303_encode_baud_rate(tty, port, &buf[0]);
501 
502 	/* For reference buf[4]=0 is 1 stop bits */
503 	/* For reference buf[4]=1 is 1.5 stop bits */
504 	/* For reference buf[4]=2 is 2 stop bits */
505 	if (C_CSTOPB(tty)) {
506 		/*
507 		 * NOTE: Comply with "real" UARTs / RS232:
508 		 *       use 1.5 instead of 2 stop bits with 5 data bits
509 		 */
510 		if (C_CSIZE(tty) == CS5) {
511 			buf[4] = 1;
512 			dev_dbg(&port->dev, "stop bits = 1.5\n");
513 		} else {
514 			buf[4] = 2;
515 			dev_dbg(&port->dev, "stop bits = 2\n");
516 		}
517 	} else {
518 		buf[4] = 0;
519 		dev_dbg(&port->dev, "stop bits = 1\n");
520 	}
521 
522 	if (C_PARENB(tty)) {
523 		/* For reference buf[5]=0 is none parity */
524 		/* For reference buf[5]=1 is odd parity */
525 		/* For reference buf[5]=2 is even parity */
526 		/* For reference buf[5]=3 is mark parity */
527 		/* For reference buf[5]=4 is space parity */
528 		if (C_PARODD(tty)) {
529 			if (C_CMSPAR(tty)) {
530 				buf[5] = 3;
531 				dev_dbg(&port->dev, "parity = mark\n");
532 			} else {
533 				buf[5] = 1;
534 				dev_dbg(&port->dev, "parity = odd\n");
535 			}
536 		} else {
537 			if (C_CMSPAR(tty)) {
538 				buf[5] = 4;
539 				dev_dbg(&port->dev, "parity = space\n");
540 			} else {
541 				buf[5] = 2;
542 				dev_dbg(&port->dev, "parity = even\n");
543 			}
544 		}
545 	} else {
546 		buf[5] = 0;
547 		dev_dbg(&port->dev, "parity = none\n");
548 	}
549 
550 	/*
551 	 * Some PL2303 are known to lose bytes if you change serial settings
552 	 * even to the same values as before. Thus we actually need to filter
553 	 * in this specific case.
554 	 *
555 	 * Note that the tty_termios_hw_change check above is not sufficient
556 	 * as a previously requested baud rate may differ from the one
557 	 * actually used (and stored in old_termios).
558 	 *
559 	 * NOTE: No additional locking needed for line_settings as it is
560 	 *       only used in set_termios, which is serialised against itself.
561 	 */
562 	if (!old_termios || memcmp(buf, priv->line_settings, 7)) {
563 		ret = pl2303_set_line_request(port, buf);
564 		if (!ret)
565 			memcpy(priv->line_settings, buf, 7);
566 	}
567 
568 	/* change control lines if we are switching to or from B0 */
569 	spin_lock_irqsave(&priv->lock, flags);
570 	control = priv->line_control;
571 	if (C_BAUD(tty) == B0)
572 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
573 	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
574 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
575 	if (control != priv->line_control) {
576 		control = priv->line_control;
577 		spin_unlock_irqrestore(&priv->lock, flags);
578 		pl2303_set_control_lines(port, control);
579 	} else {
580 		spin_unlock_irqrestore(&priv->lock, flags);
581 	}
582 
583 	if (C_CRTSCTS(tty)) {
584 		if (spriv->quirks & PL2303_QUIRK_LEGACY)
585 			pl2303_vendor_write(serial, 0x0, 0x41);
586 		else
587 			pl2303_vendor_write(serial, 0x0, 0x61);
588 	} else {
589 		pl2303_vendor_write(serial, 0x0, 0x0);
590 	}
591 
592 	kfree(buf);
593 }
594 
595 static void pl2303_dtr_rts(struct usb_serial_port *port, int on)
596 {
597 	struct pl2303_private *priv = usb_get_serial_port_data(port);
598 	unsigned long flags;
599 	u8 control;
600 
601 	spin_lock_irqsave(&priv->lock, flags);
602 	if (on)
603 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
604 	else
605 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
606 	control = priv->line_control;
607 	spin_unlock_irqrestore(&priv->lock, flags);
608 
609 	pl2303_set_control_lines(port, control);
610 }
611 
612 static void pl2303_close(struct usb_serial_port *port)
613 {
614 	usb_serial_generic_close(port);
615 	usb_kill_urb(port->interrupt_in_urb);
616 }
617 
618 static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
619 {
620 	struct usb_serial *serial = port->serial;
621 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
622 	int result;
623 
624 	if (spriv->quirks & PL2303_QUIRK_LEGACY) {
625 		usb_clear_halt(serial->dev, port->write_urb->pipe);
626 		usb_clear_halt(serial->dev, port->read_urb->pipe);
627 	} else {
628 		/* reset upstream data pipes */
629 		pl2303_vendor_write(serial, 8, 0);
630 		pl2303_vendor_write(serial, 9, 0);
631 	}
632 
633 	/* Setup termios */
634 	if (tty)
635 		pl2303_set_termios(tty, port, NULL);
636 
637 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
638 	if (result) {
639 		dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
640 			result);
641 		return result;
642 	}
643 
644 	result = usb_serial_generic_open(tty, port);
645 	if (result) {
646 		usb_kill_urb(port->interrupt_in_urb);
647 		return result;
648 	}
649 
650 	return 0;
651 }
652 
653 static int pl2303_tiocmset(struct tty_struct *tty,
654 			   unsigned int set, unsigned int clear)
655 {
656 	struct usb_serial_port *port = tty->driver_data;
657 	struct pl2303_private *priv = usb_get_serial_port_data(port);
658 	unsigned long flags;
659 	u8 control;
660 	int ret;
661 
662 	spin_lock_irqsave(&priv->lock, flags);
663 	if (set & TIOCM_RTS)
664 		priv->line_control |= CONTROL_RTS;
665 	if (set & TIOCM_DTR)
666 		priv->line_control |= CONTROL_DTR;
667 	if (clear & TIOCM_RTS)
668 		priv->line_control &= ~CONTROL_RTS;
669 	if (clear & TIOCM_DTR)
670 		priv->line_control &= ~CONTROL_DTR;
671 	control = priv->line_control;
672 	spin_unlock_irqrestore(&priv->lock, flags);
673 
674 	ret = pl2303_set_control_lines(port, control);
675 	if (ret)
676 		return usb_translate_errors(ret);
677 
678 	return 0;
679 }
680 
681 static int pl2303_tiocmget(struct tty_struct *tty)
682 {
683 	struct usb_serial_port *port = tty->driver_data;
684 	struct pl2303_private *priv = usb_get_serial_port_data(port);
685 	unsigned long flags;
686 	unsigned int mcr;
687 	unsigned int status;
688 	unsigned int result;
689 
690 	spin_lock_irqsave(&priv->lock, flags);
691 	mcr = priv->line_control;
692 	status = priv->line_status;
693 	spin_unlock_irqrestore(&priv->lock, flags);
694 
695 	result = ((mcr & CONTROL_DTR)		? TIOCM_DTR : 0)
696 		  | ((mcr & CONTROL_RTS)	? TIOCM_RTS : 0)
697 		  | ((status & UART_CTS)	? TIOCM_CTS : 0)
698 		  | ((status & UART_DSR)	? TIOCM_DSR : 0)
699 		  | ((status & UART_RING)	? TIOCM_RI  : 0)
700 		  | ((status & UART_DCD)	? TIOCM_CD  : 0);
701 
702 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
703 
704 	return result;
705 }
706 
707 static int pl2303_carrier_raised(struct usb_serial_port *port)
708 {
709 	struct pl2303_private *priv = usb_get_serial_port_data(port);
710 
711 	if (priv->line_status & UART_DCD)
712 		return 1;
713 
714 	return 0;
715 }
716 
717 static int pl2303_ioctl(struct tty_struct *tty,
718 			unsigned int cmd, unsigned long arg)
719 {
720 	struct serial_struct ser;
721 	struct usb_serial_port *port = tty->driver_data;
722 
723 	switch (cmd) {
724 	case TIOCGSERIAL:
725 		memset(&ser, 0, sizeof ser);
726 		ser.type = PORT_16654;
727 		ser.line = port->minor;
728 		ser.port = port->port_number;
729 		ser.baud_base = 460800;
730 
731 		if (copy_to_user((void __user *)arg, &ser, sizeof ser))
732 			return -EFAULT;
733 
734 		return 0;
735 	default:
736 		break;
737 	}
738 
739 	return -ENOIOCTLCMD;
740 }
741 
742 static void pl2303_break_ctl(struct tty_struct *tty, int break_state)
743 {
744 	struct usb_serial_port *port = tty->driver_data;
745 	struct usb_serial *serial = port->serial;
746 	u16 state;
747 	int result;
748 
749 	if (break_state == 0)
750 		state = BREAK_OFF;
751 	else
752 		state = BREAK_ON;
753 
754 	dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
755 			state == BREAK_OFF ? "off" : "on");
756 
757 	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
758 				 BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
759 				 0, NULL, 0, 100);
760 	if (result)
761 		dev_err(&port->dev, "error sending break = %d\n", result);
762 }
763 
764 static void pl2303_update_line_status(struct usb_serial_port *port,
765 				      unsigned char *data,
766 				      unsigned int actual_length)
767 {
768 	struct usb_serial *serial = port->serial;
769 	struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
770 	struct pl2303_private *priv = usb_get_serial_port_data(port);
771 	struct tty_struct *tty;
772 	unsigned long flags;
773 	unsigned int status_idx = UART_STATE_INDEX;
774 	u8 status;
775 	u8 delta;
776 
777 	if (spriv->quirks & PL2303_QUIRK_UART_STATE_IDX0)
778 		status_idx = 0;
779 
780 	if (actual_length < status_idx + 1)
781 		return;
782 
783 	status = data[status_idx];
784 
785 	/* Save off the uart status for others to look at */
786 	spin_lock_irqsave(&priv->lock, flags);
787 	delta = priv->line_status ^ status;
788 	priv->line_status = status;
789 	spin_unlock_irqrestore(&priv->lock, flags);
790 
791 	if (status & UART_BREAK_ERROR)
792 		usb_serial_handle_break(port);
793 
794 	if (delta & UART_STATE_MSR_MASK) {
795 		if (delta & UART_CTS)
796 			port->icount.cts++;
797 		if (delta & UART_DSR)
798 			port->icount.dsr++;
799 		if (delta & UART_RING)
800 			port->icount.rng++;
801 		if (delta & UART_DCD) {
802 			port->icount.dcd++;
803 			tty = tty_port_tty_get(&port->port);
804 			if (tty) {
805 				usb_serial_handle_dcd_change(port, tty,
806 							status & UART_DCD);
807 				tty_kref_put(tty);
808 			}
809 		}
810 
811 		wake_up_interruptible(&port->port.delta_msr_wait);
812 	}
813 }
814 
815 static void pl2303_read_int_callback(struct urb *urb)
816 {
817 	struct usb_serial_port *port =  urb->context;
818 	unsigned char *data = urb->transfer_buffer;
819 	unsigned int actual_length = urb->actual_length;
820 	int status = urb->status;
821 	int retval;
822 
823 	switch (status) {
824 	case 0:
825 		/* success */
826 		break;
827 	case -ECONNRESET:
828 	case -ENOENT:
829 	case -ESHUTDOWN:
830 		/* this urb is terminated, clean up */
831 		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
832 			__func__, status);
833 		return;
834 	default:
835 		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
836 			__func__, status);
837 		goto exit;
838 	}
839 
840 	usb_serial_debug_data(&port->dev, __func__,
841 			      urb->actual_length, urb->transfer_buffer);
842 
843 	pl2303_update_line_status(port, data, actual_length);
844 
845 exit:
846 	retval = usb_submit_urb(urb, GFP_ATOMIC);
847 	if (retval) {
848 		dev_err(&port->dev,
849 			"%s - usb_submit_urb failed with result %d\n",
850 			__func__, retval);
851 	}
852 }
853 
854 static void pl2303_process_read_urb(struct urb *urb)
855 {
856 	struct usb_serial_port *port = urb->context;
857 	struct pl2303_private *priv = usb_get_serial_port_data(port);
858 	unsigned char *data = urb->transfer_buffer;
859 	char tty_flag = TTY_NORMAL;
860 	unsigned long flags;
861 	u8 line_status;
862 	int i;
863 
864 	/* update line status */
865 	spin_lock_irqsave(&priv->lock, flags);
866 	line_status = priv->line_status;
867 	priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
868 	spin_unlock_irqrestore(&priv->lock, flags);
869 
870 	if (!urb->actual_length)
871 		return;
872 
873 	/*
874 	 * Break takes precedence over parity, which takes precedence over
875 	 * framing errors.
876 	 */
877 	if (line_status & UART_BREAK_ERROR)
878 		tty_flag = TTY_BREAK;
879 	else if (line_status & UART_PARITY_ERROR)
880 		tty_flag = TTY_PARITY;
881 	else if (line_status & UART_FRAME_ERROR)
882 		tty_flag = TTY_FRAME;
883 
884 	if (tty_flag != TTY_NORMAL)
885 		dev_dbg(&port->dev, "%s - tty_flag = %d\n", __func__,
886 								tty_flag);
887 	/* overrun is special, not associated with a char */
888 	if (line_status & UART_OVERRUN_ERROR)
889 		tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
890 
891 	if (port->port.console && port->sysrq) {
892 		for (i = 0; i < urb->actual_length; ++i)
893 			if (!usb_serial_handle_sysrq_char(port, data[i]))
894 				tty_insert_flip_char(&port->port, data[i],
895 						tty_flag);
896 	} else {
897 		tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
898 							urb->actual_length);
899 	}
900 
901 	tty_flip_buffer_push(&port->port);
902 }
903 
904 static struct usb_serial_driver pl2303_device = {
905 	.driver = {
906 		.owner =	THIS_MODULE,
907 		.name =		"pl2303",
908 	},
909 	.id_table =		id_table,
910 	.num_ports =		1,
911 	.bulk_in_size =		256,
912 	.bulk_out_size =	256,
913 	.open =			pl2303_open,
914 	.close =		pl2303_close,
915 	.dtr_rts =		pl2303_dtr_rts,
916 	.carrier_raised =	pl2303_carrier_raised,
917 	.ioctl =		pl2303_ioctl,
918 	.break_ctl =		pl2303_break_ctl,
919 	.set_termios =		pl2303_set_termios,
920 	.tiocmget =		pl2303_tiocmget,
921 	.tiocmset =		pl2303_tiocmset,
922 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
923 	.process_read_urb =	pl2303_process_read_urb,
924 	.read_int_callback =	pl2303_read_int_callback,
925 	.probe =		pl2303_probe,
926 	.attach =		pl2303_startup,
927 	.release =		pl2303_release,
928 	.port_probe =		pl2303_port_probe,
929 	.port_remove =		pl2303_port_remove,
930 };
931 
932 static struct usb_serial_driver * const serial_drivers[] = {
933 	&pl2303_device, NULL
934 };
935 
936 module_usb_serial_driver(serial_drivers, id_table);
937 
938 MODULE_DESCRIPTION("Prolific PL2303 USB to serial adaptor driver");
939 MODULE_LICENSE("GPL");
940