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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
4 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
5 * Copyright 2009, Boris Hajduk <boris@hajduk.org>
6 *
7 * ch341.c implements a serial port driver for the Winchiphead CH341.
8 *
9 * The CH341 device can be used to implement an RS232 asynchronous
10 * serial port, an IEEE-1284 parallel printer port or a memory-like
11 * interface. In all cases the CH341 supports an I2C interface as well.
12 * This driver only supports the asynchronous serial interface.
13 */
14
15#include <linux/kernel.h>
16#include <linux/tty.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/usb.h>
20#include <linux/usb/serial.h>
21#include <linux/serial.h>
22#include <asm/unaligned.h>
23
24#define DEFAULT_BAUD_RATE 9600
25#define DEFAULT_TIMEOUT 1000
26
27/* flags for IO-Bits */
28#define CH341_BIT_RTS (1 << 6)
29#define CH341_BIT_DTR (1 << 5)
30
31/******************************/
32/* interrupt pipe definitions */
33/******************************/
34/* always 4 interrupt bytes */
35/* first irq byte normally 0x08 */
36/* second irq byte base 0x7d + below */
37/* third irq byte base 0x94 + below */
38/* fourth irq byte normally 0xee */
39
40/* second interrupt byte */
41#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
42
43/* status returned in third interrupt answer byte, inverted in data
44 from irq */
45#define CH341_BIT_CTS 0x01
46#define CH341_BIT_DSR 0x02
47#define CH341_BIT_RI 0x04
48#define CH341_BIT_DCD 0x08
49#define CH341_BITS_MODEM_STAT 0x0f /* all bits */
50
51/*******************************/
52/* baudrate calculation factor */
53/*******************************/
54#define CH341_BAUDBASE_FACTOR 1532620800
55#define CH341_BAUDBASE_DIVMAX 3
56
57/* Break support - the information used to implement this was gleaned from
58 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
59 */
60
61#define CH341_REQ_READ_VERSION 0x5F
62#define CH341_REQ_WRITE_REG 0x9A
63#define CH341_REQ_READ_REG 0x95
64#define CH341_REQ_SERIAL_INIT 0xA1
65#define CH341_REQ_MODEM_CTRL 0xA4
66
67#define CH341_REG_BREAK 0x05
68#define CH341_REG_LCR 0x18
69#define CH341_NBREAK_BITS 0x01
70
71#define CH341_LCR_ENABLE_RX 0x80
72#define CH341_LCR_ENABLE_TX 0x40
73#define CH341_LCR_MARK_SPACE 0x20
74#define CH341_LCR_PAR_EVEN 0x10
75#define CH341_LCR_ENABLE_PAR 0x08
76#define CH341_LCR_STOP_BITS_2 0x04
77#define CH341_LCR_CS8 0x03
78#define CH341_LCR_CS7 0x02
79#define CH341_LCR_CS6 0x01
80#define CH341_LCR_CS5 0x00
81
82static const struct usb_device_id id_table[] = {
83 { USB_DEVICE(0x4348, 0x5523) },
84 { USB_DEVICE(0x1a86, 0x7523) },
85 { USB_DEVICE(0x1a86, 0x5523) },
86 { },
87};
88MODULE_DEVICE_TABLE(usb, id_table);
89
90struct ch341_private {
91 spinlock_t lock; /* access lock */
92 unsigned baud_rate; /* set baud rate */
93 u8 mcr;
94 u8 msr;
95 u8 lcr;
96};
97
98static void ch341_set_termios(struct tty_struct *tty,
99 struct usb_serial_port *port,
100 struct ktermios *old_termios);
101
102static int ch341_control_out(struct usb_device *dev, u8 request,
103 u16 value, u16 index)
104{
105 int r;
106
107 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
108 request, value, index);
109
110 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
111 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
112 value, index, NULL, 0, DEFAULT_TIMEOUT);
113 if (r < 0)
114 dev_err(&dev->dev, "failed to send control message: %d\n", r);
115
116 return r;
117}
118
119static int ch341_control_in(struct usb_device *dev,
120 u8 request, u16 value, u16 index,
121 char *buf, unsigned bufsize)
122{
123 int r;
124
125 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
126 request, value, index, bufsize);
127
128 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
129 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
130 value, index, buf, bufsize, DEFAULT_TIMEOUT);
131 if (r < (int)bufsize) {
132 if (r >= 0) {
133 dev_err(&dev->dev,
134 "short control message received (%d < %u)\n",
135 r, bufsize);
136 r = -EIO;
137 }
138
139 dev_err(&dev->dev, "failed to receive control message: %d\n",
140 r);
141 return r;
142 }
143
144 return 0;
145}
146
147static int ch341_set_baudrate_lcr(struct usb_device *dev,
148 struct ch341_private *priv, u8 lcr)
149{
150 short a;
151 int r;
152 unsigned long factor;
153 short divisor;
154
155 if (!priv->baud_rate)
156 return -EINVAL;
157 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
158 divisor = CH341_BAUDBASE_DIVMAX;
159
160 while ((factor > 0xfff0) && divisor) {
161 factor >>= 3;
162 divisor--;
163 }
164
165 if (factor > 0xfff0)
166 return -EINVAL;
167
168 factor = 0x10000 - factor;
169 a = (factor & 0xff00) | divisor;
170
171 /*
172 * CH341A buffers data until a full endpoint-size packet (32 bytes)
173 * has been received unless bit 7 is set.
174 */
175 a |= BIT(7);
176
177 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
178 if (r)
179 return r;
180
181 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
182 if (r)
183 return r;
184
185 return r;
186}
187
188static int ch341_set_handshake(struct usb_device *dev, u8 control)
189{
190 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
191}
192
193static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
194{
195 const unsigned int size = 2;
196 char *buffer;
197 int r;
198 unsigned long flags;
199
200 buffer = kmalloc(size, GFP_KERNEL);
201 if (!buffer)
202 return -ENOMEM;
203
204 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
205 if (r < 0)
206 goto out;
207
208 spin_lock_irqsave(&priv->lock, flags);
209 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
210 spin_unlock_irqrestore(&priv->lock, flags);
211
212out: kfree(buffer);
213 return r;
214}
215
216/* -------------------------------------------------------------------------- */
217
218static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
219{
220 const unsigned int size = 2;
221 char *buffer;
222 int r;
223
224 buffer = kmalloc(size, GFP_KERNEL);
225 if (!buffer)
226 return -ENOMEM;
227
228 /* expect two bytes 0x27 0x00 */
229 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
230 if (r < 0)
231 goto out;
232 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
233
234 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
235 if (r < 0)
236 goto out;
237
238 r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
239 if (r < 0)
240 goto out;
241
242 r = ch341_set_handshake(dev, priv->mcr);
243
244out: kfree(buffer);
245 return r;
246}
247
248static int ch341_port_probe(struct usb_serial_port *port)
249{
250 struct ch341_private *priv;
251 int r;
252
253 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
254 if (!priv)
255 return -ENOMEM;
256
257 spin_lock_init(&priv->lock);
258 priv->baud_rate = DEFAULT_BAUD_RATE;
259 /*
260 * Some CH340 devices appear unable to change the initial LCR
261 * settings, so set a sane 8N1 default.
262 */
263 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
264
265 r = ch341_configure(port->serial->dev, priv);
266 if (r < 0)
267 goto error;
268
269 usb_set_serial_port_data(port, priv);
270 return 0;
271
272error: kfree(priv);
273 return r;
274}
275
276static int ch341_port_remove(struct usb_serial_port *port)
277{
278 struct ch341_private *priv;
279
280 priv = usb_get_serial_port_data(port);
281 kfree(priv);
282
283 return 0;
284}
285
286static int ch341_carrier_raised(struct usb_serial_port *port)
287{
288 struct ch341_private *priv = usb_get_serial_port_data(port);
289 if (priv->msr & CH341_BIT_DCD)
290 return 1;
291 return 0;
292}
293
294static void ch341_dtr_rts(struct usb_serial_port *port, int on)
295{
296 struct ch341_private *priv = usb_get_serial_port_data(port);
297 unsigned long flags;
298
299 /* drop DTR and RTS */
300 spin_lock_irqsave(&priv->lock, flags);
301 if (on)
302 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
303 else
304 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
305 spin_unlock_irqrestore(&priv->lock, flags);
306 ch341_set_handshake(port->serial->dev, priv->mcr);
307}
308
309static void ch341_close(struct usb_serial_port *port)
310{
311 usb_serial_generic_close(port);
312 usb_kill_urb(port->interrupt_in_urb);
313}
314
315
316/* open this device, set default parameters */
317static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
318{
319 struct ch341_private *priv = usb_get_serial_port_data(port);
320 int r;
321
322 if (tty)
323 ch341_set_termios(tty, port, NULL);
324
325 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
326 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
327 if (r) {
328 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
329 __func__, r);
330 return r;
331 }
332
333 r = ch341_get_status(port->serial->dev, priv);
334 if (r < 0) {
335 dev_err(&port->dev, "failed to read modem status: %d\n", r);
336 goto err_kill_interrupt_urb;
337 }
338
339 r = usb_serial_generic_open(tty, port);
340 if (r)
341 goto err_kill_interrupt_urb;
342
343 return 0;
344
345err_kill_interrupt_urb:
346 usb_kill_urb(port->interrupt_in_urb);
347
348 return r;
349}
350
351/* Old_termios contains the original termios settings and
352 * tty->termios contains the new setting to be used.
353 */
354static void ch341_set_termios(struct tty_struct *tty,
355 struct usb_serial_port *port, struct ktermios *old_termios)
356{
357 struct ch341_private *priv = usb_get_serial_port_data(port);
358 unsigned baud_rate;
359 unsigned long flags;
360 u8 lcr;
361 int r;
362
363 /* redundant changes may cause the chip to lose bytes */
364 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
365 return;
366
367 baud_rate = tty_get_baud_rate(tty);
368
369 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
370
371 switch (C_CSIZE(tty)) {
372 case CS5:
373 lcr |= CH341_LCR_CS5;
374 break;
375 case CS6:
376 lcr |= CH341_LCR_CS6;
377 break;
378 case CS7:
379 lcr |= CH341_LCR_CS7;
380 break;
381 case CS8:
382 lcr |= CH341_LCR_CS8;
383 break;
384 }
385
386 if (C_PARENB(tty)) {
387 lcr |= CH341_LCR_ENABLE_PAR;
388 if (C_PARODD(tty) == 0)
389 lcr |= CH341_LCR_PAR_EVEN;
390 if (C_CMSPAR(tty))
391 lcr |= CH341_LCR_MARK_SPACE;
392 }
393
394 if (C_CSTOPB(tty))
395 lcr |= CH341_LCR_STOP_BITS_2;
396
397 if (baud_rate) {
398 priv->baud_rate = baud_rate;
399
400 r = ch341_set_baudrate_lcr(port->serial->dev, priv, lcr);
401 if (r < 0 && old_termios) {
402 priv->baud_rate = tty_termios_baud_rate(old_termios);
403 tty_termios_copy_hw(&tty->termios, old_termios);
404 } else if (r == 0) {
405 priv->lcr = lcr;
406 }
407 }
408
409 spin_lock_irqsave(&priv->lock, flags);
410 if (C_BAUD(tty) == B0)
411 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
412 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
413 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
414 spin_unlock_irqrestore(&priv->lock, flags);
415
416 ch341_set_handshake(port->serial->dev, priv->mcr);
417}
418
419static void ch341_break_ctl(struct tty_struct *tty, int break_state)
420{
421 const uint16_t ch341_break_reg =
422 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
423 struct usb_serial_port *port = tty->driver_data;
424 int r;
425 uint16_t reg_contents;
426 uint8_t *break_reg;
427
428 break_reg = kmalloc(2, GFP_KERNEL);
429 if (!break_reg)
430 return;
431
432 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
433 ch341_break_reg, 0, break_reg, 2);
434 if (r < 0) {
435 dev_err(&port->dev, "%s - USB control read error (%d)\n",
436 __func__, r);
437 goto out;
438 }
439 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
440 __func__, break_reg[0], break_reg[1]);
441 if (break_state != 0) {
442 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
443 break_reg[0] &= ~CH341_NBREAK_BITS;
444 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
445 } else {
446 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
447 break_reg[0] |= CH341_NBREAK_BITS;
448 break_reg[1] |= CH341_LCR_ENABLE_TX;
449 }
450 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
451 __func__, break_reg[0], break_reg[1]);
452 reg_contents = get_unaligned_le16(break_reg);
453 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
454 ch341_break_reg, reg_contents);
455 if (r < 0)
456 dev_err(&port->dev, "%s - USB control write error (%d)\n",
457 __func__, r);
458out:
459 kfree(break_reg);
460}
461
462static int ch341_tiocmset(struct tty_struct *tty,
463 unsigned int set, unsigned int clear)
464{
465 struct usb_serial_port *port = tty->driver_data;
466 struct ch341_private *priv = usb_get_serial_port_data(port);
467 unsigned long flags;
468 u8 control;
469
470 spin_lock_irqsave(&priv->lock, flags);
471 if (set & TIOCM_RTS)
472 priv->mcr |= CH341_BIT_RTS;
473 if (set & TIOCM_DTR)
474 priv->mcr |= CH341_BIT_DTR;
475 if (clear & TIOCM_RTS)
476 priv->mcr &= ~CH341_BIT_RTS;
477 if (clear & TIOCM_DTR)
478 priv->mcr &= ~CH341_BIT_DTR;
479 control = priv->mcr;
480 spin_unlock_irqrestore(&priv->lock, flags);
481
482 return ch341_set_handshake(port->serial->dev, control);
483}
484
485static void ch341_update_status(struct usb_serial_port *port,
486 unsigned char *data, size_t len)
487{
488 struct ch341_private *priv = usb_get_serial_port_data(port);
489 struct tty_struct *tty;
490 unsigned long flags;
491 u8 status;
492 u8 delta;
493
494 if (len < 4)
495 return;
496
497 status = ~data[2] & CH341_BITS_MODEM_STAT;
498
499 spin_lock_irqsave(&priv->lock, flags);
500 delta = status ^ priv->msr;
501 priv->msr = status;
502 spin_unlock_irqrestore(&priv->lock, flags);
503
504 if (data[1] & CH341_MULT_STAT)
505 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
506
507 if (!delta)
508 return;
509
510 if (delta & CH341_BIT_CTS)
511 port->icount.cts++;
512 if (delta & CH341_BIT_DSR)
513 port->icount.dsr++;
514 if (delta & CH341_BIT_RI)
515 port->icount.rng++;
516 if (delta & CH341_BIT_DCD) {
517 port->icount.dcd++;
518 tty = tty_port_tty_get(&port->port);
519 if (tty) {
520 usb_serial_handle_dcd_change(port, tty,
521 status & CH341_BIT_DCD);
522 tty_kref_put(tty);
523 }
524 }
525
526 wake_up_interruptible(&port->port.delta_msr_wait);
527}
528
529static void ch341_read_int_callback(struct urb *urb)
530{
531 struct usb_serial_port *port = urb->context;
532 unsigned char *data = urb->transfer_buffer;
533 unsigned int len = urb->actual_length;
534 int status;
535
536 switch (urb->status) {
537 case 0:
538 /* success */
539 break;
540 case -ECONNRESET:
541 case -ENOENT:
542 case -ESHUTDOWN:
543 /* this urb is terminated, clean up */
544 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
545 __func__, urb->status);
546 return;
547 default:
548 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
549 __func__, urb->status);
550 goto exit;
551 }
552
553 usb_serial_debug_data(&port->dev, __func__, len, data);
554 ch341_update_status(port, data, len);
555exit:
556 status = usb_submit_urb(urb, GFP_ATOMIC);
557 if (status) {
558 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
559 __func__, status);
560 }
561}
562
563static int ch341_tiocmget(struct tty_struct *tty)
564{
565 struct usb_serial_port *port = tty->driver_data;
566 struct ch341_private *priv = usb_get_serial_port_data(port);
567 unsigned long flags;
568 u8 mcr;
569 u8 status;
570 unsigned int result;
571
572 spin_lock_irqsave(&priv->lock, flags);
573 mcr = priv->mcr;
574 status = priv->msr;
575 spin_unlock_irqrestore(&priv->lock, flags);
576
577 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
578 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
579 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
580 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
581 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
582 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
583
584 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
585
586 return result;
587}
588
589static int ch341_reset_resume(struct usb_serial *serial)
590{
591 struct usb_serial_port *port = serial->port[0];
592 struct ch341_private *priv = usb_get_serial_port_data(port);
593 int ret;
594
595 /* reconfigure ch341 serial port after bus-reset */
596 ch341_configure(serial->dev, priv);
597
598 if (tty_port_initialized(&port->port)) {
599 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
600 if (ret) {
601 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
602 ret);
603 return ret;
604 }
605
606 ret = ch341_get_status(port->serial->dev, priv);
607 if (ret < 0) {
608 dev_err(&port->dev, "failed to read modem status: %d\n",
609 ret);
610 }
611 }
612
613 return usb_serial_generic_resume(serial);
614}
615
616static struct usb_serial_driver ch341_device = {
617 .driver = {
618 .owner = THIS_MODULE,
619 .name = "ch341-uart",
620 },
621 .id_table = id_table,
622 .num_ports = 1,
623 .open = ch341_open,
624 .dtr_rts = ch341_dtr_rts,
625 .carrier_raised = ch341_carrier_raised,
626 .close = ch341_close,
627 .set_termios = ch341_set_termios,
628 .break_ctl = ch341_break_ctl,
629 .tiocmget = ch341_tiocmget,
630 .tiocmset = ch341_tiocmset,
631 .tiocmiwait = usb_serial_generic_tiocmiwait,
632 .read_int_callback = ch341_read_int_callback,
633 .port_probe = ch341_port_probe,
634 .port_remove = ch341_port_remove,
635 .reset_resume = ch341_reset_resume,
636};
637
638static struct usb_serial_driver * const serial_drivers[] = {
639 &ch341_device, NULL
640};
641
642module_usb_serial_driver(serial_drivers, id_table);
643
644MODULE_LICENSE("GPL v2");
1/*
2 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
3 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
4 * Copyright 2009, Boris Hajduk <boris@hajduk.org>
5 *
6 * ch341.c implements a serial port driver for the Winchiphead CH341.
7 *
8 * The CH341 device can be used to implement an RS232 asynchronous
9 * serial port, an IEEE-1284 parallel printer port or a memory-like
10 * interface. In all cases the CH341 supports an I2C interface as well.
11 * This driver only supports the asynchronous serial interface.
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License version
15 * 2 as published by the Free Software Foundation.
16 */
17
18#include <linux/kernel.h>
19#include <linux/init.h>
20#include <linux/tty.h>
21#include <linux/module.h>
22#include <linux/slab.h>
23#include <linux/usb.h>
24#include <linux/usb/serial.h>
25#include <linux/serial.h>
26#include <asm/unaligned.h>
27
28#define DEFAULT_BAUD_RATE 9600
29#define DEFAULT_TIMEOUT 1000
30
31/* flags for IO-Bits */
32#define CH341_BIT_RTS (1 << 6)
33#define CH341_BIT_DTR (1 << 5)
34
35/******************************/
36/* interrupt pipe definitions */
37/******************************/
38/* always 4 interrupt bytes */
39/* first irq byte normally 0x08 */
40/* second irq byte base 0x7d + below */
41/* third irq byte base 0x94 + below */
42/* fourth irq byte normally 0xee */
43
44/* second interrupt byte */
45#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
46
47/* status returned in third interrupt answer byte, inverted in data
48 from irq */
49#define CH341_BIT_CTS 0x01
50#define CH341_BIT_DSR 0x02
51#define CH341_BIT_RI 0x04
52#define CH341_BIT_DCD 0x08
53#define CH341_BITS_MODEM_STAT 0x0f /* all bits */
54
55/*******************************/
56/* baudrate calculation factor */
57/*******************************/
58#define CH341_BAUDBASE_FACTOR 1532620800
59#define CH341_BAUDBASE_DIVMAX 3
60
61/* Break support - the information used to implement this was gleaned from
62 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
63 */
64
65#define CH341_REQ_WRITE_REG 0x9A
66#define CH341_REQ_READ_REG 0x95
67#define CH341_REG_BREAK1 0x05
68#define CH341_REG_BREAK2 0x18
69#define CH341_NBREAK_BITS_REG1 0x01
70#define CH341_NBREAK_BITS_REG2 0x40
71
72
73static bool debug;
74
75static const struct usb_device_id id_table[] = {
76 { USB_DEVICE(0x4348, 0x5523) },
77 { USB_DEVICE(0x1a86, 0x7523) },
78 { USB_DEVICE(0x1a86, 0x5523) },
79 { },
80};
81MODULE_DEVICE_TABLE(usb, id_table);
82
83struct ch341_private {
84 spinlock_t lock; /* access lock */
85 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
86 unsigned baud_rate; /* set baud rate */
87 u8 line_control; /* set line control value RTS/DTR */
88 u8 line_status; /* active status of modem control inputs */
89 u8 multi_status_change; /* status changed multiple since last call */
90};
91
92static int ch341_control_out(struct usb_device *dev, u8 request,
93 u16 value, u16 index)
94{
95 int r;
96 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
97 (int)request, (int)value, (int)index);
98
99 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
100 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
101 value, index, NULL, 0, DEFAULT_TIMEOUT);
102
103 return r;
104}
105
106static int ch341_control_in(struct usb_device *dev,
107 u8 request, u16 value, u16 index,
108 char *buf, unsigned bufsize)
109{
110 int r;
111 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
112 (int)request, (int)value, (int)index, buf, (int)bufsize);
113
114 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
115 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
116 value, index, buf, bufsize, DEFAULT_TIMEOUT);
117 return r;
118}
119
120static int ch341_set_baudrate(struct usb_device *dev,
121 struct ch341_private *priv)
122{
123 short a, b;
124 int r;
125 unsigned long factor;
126 short divisor;
127
128 if (!priv->baud_rate)
129 return -EINVAL;
130 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
131 divisor = CH341_BAUDBASE_DIVMAX;
132
133 while ((factor > 0xfff0) && divisor) {
134 factor >>= 3;
135 divisor--;
136 }
137
138 if (factor > 0xfff0)
139 return -EINVAL;
140
141 factor = 0x10000 - factor;
142 a = (factor & 0xff00) | divisor;
143 b = factor & 0xff;
144
145 r = ch341_control_out(dev, 0x9a, 0x1312, a);
146 if (!r)
147 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
148
149 return r;
150}
151
152static int ch341_set_handshake(struct usb_device *dev, u8 control)
153{
154 return ch341_control_out(dev, 0xa4, ~control, 0);
155}
156
157static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
158{
159 char *buffer;
160 int r;
161 const unsigned size = 8;
162 unsigned long flags;
163
164 buffer = kmalloc(size, GFP_KERNEL);
165 if (!buffer)
166 return -ENOMEM;
167
168 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
169 if (r < 0)
170 goto out;
171
172 /* setup the private status if available */
173 if (r == 2) {
174 r = 0;
175 spin_lock_irqsave(&priv->lock, flags);
176 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
177 priv->multi_status_change = 0;
178 spin_unlock_irqrestore(&priv->lock, flags);
179 } else
180 r = -EPROTO;
181
182out: kfree(buffer);
183 return r;
184}
185
186/* -------------------------------------------------------------------------- */
187
188static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
189{
190 char *buffer;
191 int r;
192 const unsigned size = 8;
193
194 buffer = kmalloc(size, GFP_KERNEL);
195 if (!buffer)
196 return -ENOMEM;
197
198 /* expect two bytes 0x27 0x00 */
199 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
200 if (r < 0)
201 goto out;
202
203 r = ch341_control_out(dev, 0xa1, 0, 0);
204 if (r < 0)
205 goto out;
206
207 r = ch341_set_baudrate(dev, priv);
208 if (r < 0)
209 goto out;
210
211 /* expect two bytes 0x56 0x00 */
212 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
213 if (r < 0)
214 goto out;
215
216 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
217 if (r < 0)
218 goto out;
219
220 /* expect 0xff 0xee */
221 r = ch341_get_status(dev, priv);
222 if (r < 0)
223 goto out;
224
225 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
226 if (r < 0)
227 goto out;
228
229 r = ch341_set_baudrate(dev, priv);
230 if (r < 0)
231 goto out;
232
233 r = ch341_set_handshake(dev, priv->line_control);
234 if (r < 0)
235 goto out;
236
237 /* expect 0x9f 0xee */
238 r = ch341_get_status(dev, priv);
239
240out: kfree(buffer);
241 return r;
242}
243
244/* allocate private data */
245static int ch341_attach(struct usb_serial *serial)
246{
247 struct ch341_private *priv;
248 int r;
249
250 /* private data */
251 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
252 if (!priv)
253 return -ENOMEM;
254
255 spin_lock_init(&priv->lock);
256 init_waitqueue_head(&priv->delta_msr_wait);
257 priv->baud_rate = DEFAULT_BAUD_RATE;
258 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
259
260 r = ch341_configure(serial->dev, priv);
261 if (r < 0)
262 goto error;
263
264 usb_set_serial_port_data(serial->port[0], priv);
265 return 0;
266
267error: kfree(priv);
268 return r;
269}
270
271static int ch341_carrier_raised(struct usb_serial_port *port)
272{
273 struct ch341_private *priv = usb_get_serial_port_data(port);
274 if (priv->line_status & CH341_BIT_DCD)
275 return 1;
276 return 0;
277}
278
279static void ch341_dtr_rts(struct usb_serial_port *port, int on)
280{
281 struct ch341_private *priv = usb_get_serial_port_data(port);
282 unsigned long flags;
283
284 /* drop DTR and RTS */
285 spin_lock_irqsave(&priv->lock, flags);
286 if (on)
287 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
288 else
289 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
290 spin_unlock_irqrestore(&priv->lock, flags);
291 ch341_set_handshake(port->serial->dev, priv->line_control);
292 wake_up_interruptible(&priv->delta_msr_wait);
293}
294
295static void ch341_close(struct usb_serial_port *port)
296{
297 usb_serial_generic_close(port);
298 usb_kill_urb(port->interrupt_in_urb);
299}
300
301
302/* open this device, set default parameters */
303static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
304{
305 struct usb_serial *serial = port->serial;
306 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
307 int r;
308
309 priv->baud_rate = DEFAULT_BAUD_RATE;
310
311 r = ch341_configure(serial->dev, priv);
312 if (r)
313 goto out;
314
315 r = ch341_set_handshake(serial->dev, priv->line_control);
316 if (r)
317 goto out;
318
319 r = ch341_set_baudrate(serial->dev, priv);
320 if (r)
321 goto out;
322
323 dbg("%s - submitting interrupt urb", __func__);
324 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
325 if (r) {
326 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
327 " error %d\n", __func__, r);
328 ch341_close(port);
329 goto out;
330 }
331
332 r = usb_serial_generic_open(tty, port);
333
334out: return r;
335}
336
337/* Old_termios contains the original termios settings and
338 * tty->termios contains the new setting to be used.
339 */
340static void ch341_set_termios(struct tty_struct *tty,
341 struct usb_serial_port *port, struct ktermios *old_termios)
342{
343 struct ch341_private *priv = usb_get_serial_port_data(port);
344 unsigned baud_rate;
345 unsigned long flags;
346
347 baud_rate = tty_get_baud_rate(tty);
348
349 priv->baud_rate = baud_rate;
350
351 if (baud_rate) {
352 spin_lock_irqsave(&priv->lock, flags);
353 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
354 spin_unlock_irqrestore(&priv->lock, flags);
355 ch341_set_baudrate(port->serial->dev, priv);
356 } else {
357 spin_lock_irqsave(&priv->lock, flags);
358 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
359 spin_unlock_irqrestore(&priv->lock, flags);
360 }
361
362 ch341_set_handshake(port->serial->dev, priv->line_control);
363
364 /* Unimplemented:
365 * (cflag & CSIZE) : data bits [5, 8]
366 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
367 * (cflag & CSTOPB) : stop bits [1, 2]
368 */
369}
370
371static void ch341_break_ctl(struct tty_struct *tty, int break_state)
372{
373 const uint16_t ch341_break_reg =
374 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
375 struct usb_serial_port *port = tty->driver_data;
376 int r;
377 uint16_t reg_contents;
378 uint8_t *break_reg;
379
380 break_reg = kmalloc(2, GFP_KERNEL);
381 if (!break_reg) {
382 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
383 return;
384 }
385
386 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
387 ch341_break_reg, 0, break_reg, 2);
388 if (r < 0) {
389 dev_err(&port->dev, "%s - USB control read error (%d)\n",
390 __func__, r);
391 goto out;
392 }
393 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
394 __func__, break_reg[0], break_reg[1]);
395 if (break_state != 0) {
396 dbg("%s - Enter break state requested", __func__);
397 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
398 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
399 } else {
400 dbg("%s - Leave break state requested", __func__);
401 break_reg[0] |= CH341_NBREAK_BITS_REG1;
402 break_reg[1] |= CH341_NBREAK_BITS_REG2;
403 }
404 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
405 __func__, break_reg[0], break_reg[1]);
406 reg_contents = get_unaligned_le16(break_reg);
407 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
408 ch341_break_reg, reg_contents);
409 if (r < 0)
410 dev_err(&port->dev, "%s - USB control write error (%d)\n",
411 __func__, r);
412out:
413 kfree(break_reg);
414}
415
416static int ch341_tiocmset(struct tty_struct *tty,
417 unsigned int set, unsigned int clear)
418{
419 struct usb_serial_port *port = tty->driver_data;
420 struct ch341_private *priv = usb_get_serial_port_data(port);
421 unsigned long flags;
422 u8 control;
423
424 spin_lock_irqsave(&priv->lock, flags);
425 if (set & TIOCM_RTS)
426 priv->line_control |= CH341_BIT_RTS;
427 if (set & TIOCM_DTR)
428 priv->line_control |= CH341_BIT_DTR;
429 if (clear & TIOCM_RTS)
430 priv->line_control &= ~CH341_BIT_RTS;
431 if (clear & TIOCM_DTR)
432 priv->line_control &= ~CH341_BIT_DTR;
433 control = priv->line_control;
434 spin_unlock_irqrestore(&priv->lock, flags);
435
436 return ch341_set_handshake(port->serial->dev, control);
437}
438
439static void ch341_read_int_callback(struct urb *urb)
440{
441 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
442 unsigned char *data = urb->transfer_buffer;
443 unsigned int actual_length = urb->actual_length;
444 int status;
445
446 switch (urb->status) {
447 case 0:
448 /* success */
449 break;
450 case -ECONNRESET:
451 case -ENOENT:
452 case -ESHUTDOWN:
453 /* this urb is terminated, clean up */
454 dbg("%s - urb shutting down with status: %d", __func__,
455 urb->status);
456 return;
457 default:
458 dbg("%s - nonzero urb status received: %d", __func__,
459 urb->status);
460 goto exit;
461 }
462
463 usb_serial_debug_data(debug, &port->dev, __func__,
464 urb->actual_length, urb->transfer_buffer);
465
466 if (actual_length >= 4) {
467 struct ch341_private *priv = usb_get_serial_port_data(port);
468 unsigned long flags;
469 u8 prev_line_status = priv->line_status;
470
471 spin_lock_irqsave(&priv->lock, flags);
472 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
473 if ((data[1] & CH341_MULT_STAT))
474 priv->multi_status_change = 1;
475 spin_unlock_irqrestore(&priv->lock, flags);
476
477 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
478 struct tty_struct *tty = tty_port_tty_get(&port->port);
479 if (tty)
480 usb_serial_handle_dcd_change(port, tty,
481 priv->line_status & CH341_BIT_DCD);
482 tty_kref_put(tty);
483 }
484
485 wake_up_interruptible(&priv->delta_msr_wait);
486 }
487
488exit:
489 status = usb_submit_urb(urb, GFP_ATOMIC);
490 if (status)
491 dev_err(&urb->dev->dev,
492 "%s - usb_submit_urb failed with result %d\n",
493 __func__, status);
494}
495
496static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
497{
498 struct ch341_private *priv = usb_get_serial_port_data(port);
499 unsigned long flags;
500 u8 prevstatus;
501 u8 status;
502 u8 changed;
503 u8 multi_change = 0;
504
505 spin_lock_irqsave(&priv->lock, flags);
506 prevstatus = priv->line_status;
507 priv->multi_status_change = 0;
508 spin_unlock_irqrestore(&priv->lock, flags);
509
510 while (!multi_change) {
511 interruptible_sleep_on(&priv->delta_msr_wait);
512 /* see if a signal did it */
513 if (signal_pending(current))
514 return -ERESTARTSYS;
515
516 spin_lock_irqsave(&priv->lock, flags);
517 status = priv->line_status;
518 multi_change = priv->multi_status_change;
519 spin_unlock_irqrestore(&priv->lock, flags);
520
521 changed = prevstatus ^ status;
522
523 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
524 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
525 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
526 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
527 return 0;
528 }
529 prevstatus = status;
530 }
531
532 return 0;
533}
534
535static int ch341_ioctl(struct tty_struct *tty,
536 unsigned int cmd, unsigned long arg)
537{
538 struct usb_serial_port *port = tty->driver_data;
539 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
540
541 switch (cmd) {
542 case TIOCMIWAIT:
543 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
544 return wait_modem_info(port, arg);
545
546 default:
547 dbg("%s not supported = 0x%04x", __func__, cmd);
548 break;
549 }
550
551 return -ENOIOCTLCMD;
552}
553
554static int ch341_tiocmget(struct tty_struct *tty)
555{
556 struct usb_serial_port *port = tty->driver_data;
557 struct ch341_private *priv = usb_get_serial_port_data(port);
558 unsigned long flags;
559 u8 mcr;
560 u8 status;
561 unsigned int result;
562
563 spin_lock_irqsave(&priv->lock, flags);
564 mcr = priv->line_control;
565 status = priv->line_status;
566 spin_unlock_irqrestore(&priv->lock, flags);
567
568 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
569 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
570 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
571 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
572 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
573 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
574
575 dbg("%s - result = %x", __func__, result);
576
577 return result;
578}
579
580static int ch341_reset_resume(struct usb_serial *serial)
581{
582 struct ch341_private *priv;
583
584 priv = usb_get_serial_port_data(serial->port[0]);
585
586 /* reconfigure ch341 serial port after bus-reset */
587 ch341_configure(serial->dev, priv);
588
589 return 0;
590}
591
592static struct usb_serial_driver ch341_device = {
593 .driver = {
594 .owner = THIS_MODULE,
595 .name = "ch341-uart",
596 },
597 .id_table = id_table,
598 .num_ports = 1,
599 .open = ch341_open,
600 .dtr_rts = ch341_dtr_rts,
601 .carrier_raised = ch341_carrier_raised,
602 .close = ch341_close,
603 .ioctl = ch341_ioctl,
604 .set_termios = ch341_set_termios,
605 .break_ctl = ch341_break_ctl,
606 .tiocmget = ch341_tiocmget,
607 .tiocmset = ch341_tiocmset,
608 .read_int_callback = ch341_read_int_callback,
609 .attach = ch341_attach,
610 .reset_resume = ch341_reset_resume,
611};
612
613static struct usb_serial_driver * const serial_drivers[] = {
614 &ch341_device, NULL
615};
616
617module_usb_serial_driver(serial_drivers, id_table);
618
619MODULE_LICENSE("GPL");
620
621module_param(debug, bool, S_IRUGO | S_IWUSR);
622MODULE_PARM_DESC(debug, "Debug enabled or not");