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/tty.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/usb.h>
23 #include <linux/usb/serial.h>
24 #include <linux/serial.h>
25 #include <asm/unaligned.h>
26
27 #define DEFAULT_BAUD_RATE 9600
28 #define DEFAULT_TIMEOUT 1000
29
30 /* flags for IO-Bits */
31 #define CH341_BIT_RTS (1 << 6)
32 #define CH341_BIT_DTR (1 << 5)
33
34 /******************************/
35 /* interrupt pipe definitions */
36 /******************************/
37 /* always 4 interrupt bytes */
38 /* first irq byte normally 0x08 */
39 /* second irq byte base 0x7d + below */
40 /* third irq byte base 0x94 + below */
41 /* fourth irq byte normally 0xee */
42
43 /* second interrupt byte */
44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
45
46 /* status returned in third interrupt answer byte, inverted in data
47 from irq */
48 #define CH341_BIT_CTS 0x01
49 #define CH341_BIT_DSR 0x02
50 #define CH341_BIT_RI 0x04
51 #define CH341_BIT_DCD 0x08
52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
53
54 /*******************************/
55 /* baudrate calculation factor */
56 /*******************************/
57 #define CH341_BAUDBASE_FACTOR 1532620800
58 #define CH341_BAUDBASE_DIVMAX 3
59
60 /* Break support - the information used to implement this was gleaned from
61 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
62 */
63
64 #define CH341_REQ_WRITE_REG 0x9A
65 #define CH341_REQ_READ_REG 0x95
66 #define CH341_REG_BREAK1 0x05
67 #define CH341_REG_BREAK2 0x18
68 #define CH341_NBREAK_BITS_REG1 0x01
69 #define CH341_NBREAK_BITS_REG2 0x40
70
71
72 static const struct usb_device_id id_table[] = {
73 { USB_DEVICE(0x4348, 0x5523) },
74 { USB_DEVICE(0x1a86, 0x7523) },
75 { USB_DEVICE(0x1a86, 0x5523) },
76 { },
77 };
78 MODULE_DEVICE_TABLE(usb, id_table);
79
80 struct ch341_private {
81 spinlock_t lock; /* access lock */
82 unsigned baud_rate; /* set baud rate */
83 u8 line_control; /* set line control value RTS/DTR */
84 u8 line_status; /* active status of modem control inputs */
85 };
86
87 static void ch341_set_termios(struct tty_struct *tty,
88 struct usb_serial_port *port,
89 struct ktermios *old_termios);
90
ch341_control_out(struct usb_device * dev,u8 request,u16 value,u16 index)91 static int ch341_control_out(struct usb_device *dev, u8 request,
92 u16 value, u16 index)
93 {
94 int r;
95
96 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
97 USB_DIR_OUT|0x40, (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 if (r < 0)
103 dev_err(&dev->dev, "failed to send control message: %d\n", r);
104
105 return r;
106 }
107
ch341_control_in(struct usb_device * dev,u8 request,u16 value,u16 index,char * buf,unsigned bufsize)108 static int ch341_control_in(struct usb_device *dev,
109 u8 request, u16 value, u16 index,
110 char *buf, unsigned bufsize)
111 {
112 int r;
113
114 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
115 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
116 (int)bufsize);
117
118 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
119 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
120 value, index, buf, bufsize, DEFAULT_TIMEOUT);
121 if (r < bufsize) {
122 if (r >= 0) {
123 dev_err(&dev->dev,
124 "short control message received (%d < %u)\n",
125 r, bufsize);
126 r = -EIO;
127 }
128
129 dev_err(&dev->dev, "failed to receive control message: %d\n",
130 r);
131 return r;
132 }
133
134 return 0;
135 }
136
ch341_set_baudrate(struct usb_device * dev,struct ch341_private * priv)137 static int ch341_set_baudrate(struct usb_device *dev,
138 struct ch341_private *priv)
139 {
140 short a, b;
141 int r;
142 unsigned long factor;
143 short divisor;
144
145 if (!priv->baud_rate)
146 return -EINVAL;
147 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
148 divisor = CH341_BAUDBASE_DIVMAX;
149
150 while ((factor > 0xfff0) && divisor) {
151 factor >>= 3;
152 divisor--;
153 }
154
155 if (factor > 0xfff0)
156 return -EINVAL;
157
158 factor = 0x10000 - factor;
159 a = (factor & 0xff00) | divisor;
160 b = factor & 0xff;
161
162 r = ch341_control_out(dev, 0x9a, 0x1312, a);
163 if (!r)
164 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
165
166 return r;
167 }
168
ch341_set_handshake(struct usb_device * dev,u8 control)169 static int ch341_set_handshake(struct usb_device *dev, u8 control)
170 {
171 return ch341_control_out(dev, 0xa4, ~control, 0);
172 }
173
ch341_get_status(struct usb_device * dev,struct ch341_private * priv)174 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
175 {
176 const unsigned int size = 2;
177 char *buffer;
178 int r;
179 unsigned long flags;
180
181 buffer = kmalloc(size, GFP_KERNEL);
182 if (!buffer)
183 return -ENOMEM;
184
185 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
186 if (r < 0)
187 goto out;
188
189 spin_lock_irqsave(&priv->lock, flags);
190 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
191 spin_unlock_irqrestore(&priv->lock, flags);
192
193 out: kfree(buffer);
194 return r;
195 }
196
197 /* -------------------------------------------------------------------------- */
198
ch341_configure(struct usb_device * dev,struct ch341_private * priv)199 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
200 {
201 const unsigned int size = 2;
202 char *buffer;
203 int r;
204
205 buffer = kmalloc(size, GFP_KERNEL);
206 if (!buffer)
207 return -ENOMEM;
208
209 /* expect two bytes 0x27 0x00 */
210 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
211 if (r < 0)
212 goto out;
213
214 r = ch341_control_out(dev, 0xa1, 0, 0);
215 if (r < 0)
216 goto out;
217
218 r = ch341_set_baudrate(dev, priv);
219 if (r < 0)
220 goto out;
221
222 /* expect two bytes 0x56 0x00 */
223 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
224 if (r < 0)
225 goto out;
226
227 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
228 if (r < 0)
229 goto out;
230
231 /* expect 0xff 0xee */
232 r = ch341_get_status(dev, priv);
233 if (r < 0)
234 goto out;
235
236 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
237 if (r < 0)
238 goto out;
239
240 r = ch341_set_baudrate(dev, priv);
241 if (r < 0)
242 goto out;
243
244 r = ch341_set_handshake(dev, priv->line_control);
245 if (r < 0)
246 goto out;
247
248 /* expect 0x9f 0xee */
249 r = ch341_get_status(dev, priv);
250
251 out: kfree(buffer);
252 return r;
253 }
254
ch341_port_probe(struct usb_serial_port * port)255 static int ch341_port_probe(struct usb_serial_port *port)
256 {
257 struct ch341_private *priv;
258 int r;
259
260 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
261 if (!priv)
262 return -ENOMEM;
263
264 spin_lock_init(&priv->lock);
265 priv->baud_rate = DEFAULT_BAUD_RATE;
266
267 r = ch341_configure(port->serial->dev, priv);
268 if (r < 0)
269 goto error;
270
271 usb_set_serial_port_data(port, priv);
272 return 0;
273
274 error: kfree(priv);
275 return r;
276 }
277
ch341_port_remove(struct usb_serial_port * port)278 static int ch341_port_remove(struct usb_serial_port *port)
279 {
280 struct ch341_private *priv;
281
282 priv = usb_get_serial_port_data(port);
283 kfree(priv);
284
285 return 0;
286 }
287
ch341_carrier_raised(struct usb_serial_port * port)288 static int ch341_carrier_raised(struct usb_serial_port *port)
289 {
290 struct ch341_private *priv = usb_get_serial_port_data(port);
291 if (priv->line_status & CH341_BIT_DCD)
292 return 1;
293 return 0;
294 }
295
ch341_dtr_rts(struct usb_serial_port * port,int on)296 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
297 {
298 struct ch341_private *priv = usb_get_serial_port_data(port);
299 unsigned long flags;
300
301 /* drop DTR and RTS */
302 spin_lock_irqsave(&priv->lock, flags);
303 if (on)
304 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
305 else
306 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
307 spin_unlock_irqrestore(&priv->lock, flags);
308 ch341_set_handshake(port->serial->dev, priv->line_control);
309 }
310
ch341_close(struct usb_serial_port * port)311 static void ch341_close(struct usb_serial_port *port)
312 {
313 usb_serial_generic_close(port);
314 usb_kill_urb(port->interrupt_in_urb);
315 }
316
317
318 /* open this device, set default parameters */
ch341_open(struct tty_struct * tty,struct usb_serial_port * port)319 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
320 {
321 struct usb_serial *serial = port->serial;
322 struct ch341_private *priv = usb_get_serial_port_data(port);
323 int r;
324
325 r = ch341_configure(serial->dev, priv);
326 if (r)
327 return r;
328
329 if (tty)
330 ch341_set_termios(tty, port, NULL);
331
332 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
333 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
334 if (r) {
335 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
336 __func__, r);
337 return r;
338 }
339
340 r = usb_serial_generic_open(tty, port);
341 if (r)
342 goto err_kill_interrupt_urb;
343
344 return 0;
345
346 err_kill_interrupt_urb:
347 usb_kill_urb(port->interrupt_in_urb);
348
349 return r;
350 }
351
352 /* Old_termios contains the original termios settings and
353 * tty->termios contains the new setting to be used.
354 */
ch341_set_termios(struct tty_struct * tty,struct usb_serial_port * port,struct ktermios * old_termios)355 static void ch341_set_termios(struct tty_struct *tty,
356 struct usb_serial_port *port, struct ktermios *old_termios)
357 {
358 struct ch341_private *priv = usb_get_serial_port_data(port);
359 unsigned baud_rate;
360 unsigned long flags;
361
362 baud_rate = tty_get_baud_rate(tty);
363
364 if (baud_rate) {
365 priv->baud_rate = baud_rate;
366 ch341_set_baudrate(port->serial->dev, priv);
367 }
368
369 /* Unimplemented:
370 * (cflag & CSIZE) : data bits [5, 8]
371 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
372 * (cflag & CSTOPB) : stop bits [1, 2]
373 */
374
375 spin_lock_irqsave(&priv->lock, flags);
376 if (C_BAUD(tty) == B0)
377 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
378 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
379 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
380 spin_unlock_irqrestore(&priv->lock, flags);
381
382 ch341_set_handshake(port->serial->dev, priv->line_control);
383 }
384
ch341_break_ctl(struct tty_struct * tty,int break_state)385 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
386 {
387 const uint16_t ch341_break_reg =
388 ((uint16_t) CH341_REG_BREAK2 << 8) | CH341_REG_BREAK1;
389 struct usb_serial_port *port = tty->driver_data;
390 int r;
391 uint16_t reg_contents;
392 uint8_t *break_reg;
393
394 break_reg = kmalloc(2, GFP_KERNEL);
395 if (!break_reg)
396 return;
397
398 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
399 ch341_break_reg, 0, break_reg, 2);
400 if (r < 0) {
401 dev_err(&port->dev, "%s - USB control read error (%d)\n",
402 __func__, r);
403 goto out;
404 }
405 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
406 __func__, break_reg[0], break_reg[1]);
407 if (break_state != 0) {
408 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
409 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
410 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
411 } else {
412 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
413 break_reg[0] |= CH341_NBREAK_BITS_REG1;
414 break_reg[1] |= CH341_NBREAK_BITS_REG2;
415 }
416 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
417 __func__, break_reg[0], break_reg[1]);
418 reg_contents = get_unaligned_le16(break_reg);
419 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
420 ch341_break_reg, reg_contents);
421 if (r < 0)
422 dev_err(&port->dev, "%s - USB control write error (%d)\n",
423 __func__, r);
424 out:
425 kfree(break_reg);
426 }
427
ch341_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)428 static int ch341_tiocmset(struct tty_struct *tty,
429 unsigned int set, unsigned int clear)
430 {
431 struct usb_serial_port *port = tty->driver_data;
432 struct ch341_private *priv = usb_get_serial_port_data(port);
433 unsigned long flags;
434 u8 control;
435
436 spin_lock_irqsave(&priv->lock, flags);
437 if (set & TIOCM_RTS)
438 priv->line_control |= CH341_BIT_RTS;
439 if (set & TIOCM_DTR)
440 priv->line_control |= CH341_BIT_DTR;
441 if (clear & TIOCM_RTS)
442 priv->line_control &= ~CH341_BIT_RTS;
443 if (clear & TIOCM_DTR)
444 priv->line_control &= ~CH341_BIT_DTR;
445 control = priv->line_control;
446 spin_unlock_irqrestore(&priv->lock, flags);
447
448 return ch341_set_handshake(port->serial->dev, control);
449 }
450
ch341_update_line_status(struct usb_serial_port * port,unsigned char * data,size_t len)451 static void ch341_update_line_status(struct usb_serial_port *port,
452 unsigned char *data, size_t len)
453 {
454 struct ch341_private *priv = usb_get_serial_port_data(port);
455 struct tty_struct *tty;
456 unsigned long flags;
457 u8 status;
458 u8 delta;
459
460 if (len < 4)
461 return;
462
463 status = ~data[2] & CH341_BITS_MODEM_STAT;
464
465 spin_lock_irqsave(&priv->lock, flags);
466 delta = status ^ priv->line_status;
467 priv->line_status = status;
468 spin_unlock_irqrestore(&priv->lock, flags);
469
470 if (data[1] & CH341_MULT_STAT)
471 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
472
473 if (!delta)
474 return;
475
476 if (delta & CH341_BIT_CTS)
477 port->icount.cts++;
478 if (delta & CH341_BIT_DSR)
479 port->icount.dsr++;
480 if (delta & CH341_BIT_RI)
481 port->icount.rng++;
482 if (delta & CH341_BIT_DCD) {
483 port->icount.dcd++;
484 tty = tty_port_tty_get(&port->port);
485 if (tty) {
486 usb_serial_handle_dcd_change(port, tty,
487 status & CH341_BIT_DCD);
488 tty_kref_put(tty);
489 }
490 }
491
492 wake_up_interruptible(&port->port.delta_msr_wait);
493 }
494
ch341_read_int_callback(struct urb * urb)495 static void ch341_read_int_callback(struct urb *urb)
496 {
497 struct usb_serial_port *port = urb->context;
498 unsigned char *data = urb->transfer_buffer;
499 unsigned int len = urb->actual_length;
500 int status;
501
502 switch (urb->status) {
503 case 0:
504 /* success */
505 break;
506 case -ECONNRESET:
507 case -ENOENT:
508 case -ESHUTDOWN:
509 /* this urb is terminated, clean up */
510 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
511 __func__, urb->status);
512 return;
513 default:
514 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
515 __func__, urb->status);
516 goto exit;
517 }
518
519 usb_serial_debug_data(&port->dev, __func__, len, data);
520 ch341_update_line_status(port, data, len);
521 exit:
522 status = usb_submit_urb(urb, GFP_ATOMIC);
523 if (status) {
524 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
525 __func__, status);
526 }
527 }
528
ch341_tiocmget(struct tty_struct * tty)529 static int ch341_tiocmget(struct tty_struct *tty)
530 {
531 struct usb_serial_port *port = tty->driver_data;
532 struct ch341_private *priv = usb_get_serial_port_data(port);
533 unsigned long flags;
534 u8 mcr;
535 u8 status;
536 unsigned int result;
537
538 spin_lock_irqsave(&priv->lock, flags);
539 mcr = priv->line_control;
540 status = priv->line_status;
541 spin_unlock_irqrestore(&priv->lock, flags);
542
543 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
544 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
545 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
546 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
547 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
548 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
549
550 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
551
552 return result;
553 }
554
ch341_reset_resume(struct usb_serial * serial)555 static int ch341_reset_resume(struct usb_serial *serial)
556 {
557 struct usb_serial_port *port = serial->port[0];
558 struct ch341_private *priv = usb_get_serial_port_data(port);
559 int ret;
560
561 /* reconfigure ch341 serial port after bus-reset */
562 ch341_configure(serial->dev, priv);
563
564 if (tty_port_initialized(&port->port)) {
565 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
566 if (ret) {
567 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
568 ret);
569 return ret;
570 }
571 }
572
573 return usb_serial_generic_resume(serial);
574 }
575
576 static struct usb_serial_driver ch341_device = {
577 .driver = {
578 .owner = THIS_MODULE,
579 .name = "ch341-uart",
580 },
581 .id_table = id_table,
582 .num_ports = 1,
583 .open = ch341_open,
584 .dtr_rts = ch341_dtr_rts,
585 .carrier_raised = ch341_carrier_raised,
586 .close = ch341_close,
587 .set_termios = ch341_set_termios,
588 .break_ctl = ch341_break_ctl,
589 .tiocmget = ch341_tiocmget,
590 .tiocmset = ch341_tiocmset,
591 .tiocmiwait = usb_serial_generic_tiocmiwait,
592 .read_int_callback = ch341_read_int_callback,
593 .port_probe = ch341_port_probe,
594 .port_remove = ch341_port_remove,
595 .reset_resume = ch341_reset_resume,
596 };
597
598 static struct usb_serial_driver * const serial_drivers[] = {
599 &ch341_device, NULL
600 };
601
602 module_usb_serial_driver(serial_drivers, id_table);
603
604 MODULE_LICENSE("GPL");
605