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
73 static bool debug;
74
75 static const struct usb_device_id id_table[] = {
76 { USB_DEVICE(0x4348, 0x5523) },
77 { USB_DEVICE(0x1a86, 0x7523) },
78 { USB_DEVICE(0x1a86, 0x5523) },
79 { },
80 };
81 MODULE_DEVICE_TABLE(usb, id_table);
82
83 struct 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
ch341_control_out(struct usb_device * dev,u8 request,u16 value,u16 index)92 static 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
ch341_control_in(struct usb_device * dev,u8 request,u16 value,u16 index,char * buf,unsigned bufsize)106 static 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
ch341_set_baudrate(struct usb_device * dev,struct ch341_private * priv)120 static 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 dbg("ch341_set_baudrate(%d)", priv->baud_rate);
129
130 if (!priv->baud_rate)
131 return -EINVAL;
132 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
133 divisor = CH341_BAUDBASE_DIVMAX;
134
135 while ((factor > 0xfff0) && divisor) {
136 factor >>= 3;
137 divisor--;
138 }
139
140 if (factor > 0xfff0)
141 return -EINVAL;
142
143 factor = 0x10000 - factor;
144 a = (factor & 0xff00) | divisor;
145 b = factor & 0xff;
146
147 r = ch341_control_out(dev, 0x9a, 0x1312, a);
148 if (!r)
149 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
150
151 return r;
152 }
153
ch341_set_handshake(struct usb_device * dev,u8 control)154 static int ch341_set_handshake(struct usb_device *dev, u8 control)
155 {
156 dbg("ch341_set_handshake(0x%02x)", control);
157 return ch341_control_out(dev, 0xa4, ~control, 0);
158 }
159
ch341_get_status(struct usb_device * dev,struct ch341_private * priv)160 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
161 {
162 char *buffer;
163 int r;
164 const unsigned size = 8;
165 unsigned long flags;
166
167 dbg("ch341_get_status()");
168
169 buffer = kmalloc(size, GFP_KERNEL);
170 if (!buffer)
171 return -ENOMEM;
172
173 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
174 if (r < 0)
175 goto out;
176
177 /* setup the private status if available */
178 if (r == 2) {
179 r = 0;
180 spin_lock_irqsave(&priv->lock, flags);
181 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
182 priv->multi_status_change = 0;
183 spin_unlock_irqrestore(&priv->lock, flags);
184 } else
185 r = -EPROTO;
186
187 out: kfree(buffer);
188 return r;
189 }
190
191 /* -------------------------------------------------------------------------- */
192
ch341_configure(struct usb_device * dev,struct ch341_private * priv)193 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
194 {
195 char *buffer;
196 int r;
197 const unsigned size = 8;
198
199 dbg("ch341_configure()");
200
201 buffer = kmalloc(size, GFP_KERNEL);
202 if (!buffer)
203 return -ENOMEM;
204
205 /* expect two bytes 0x27 0x00 */
206 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
207 if (r < 0)
208 goto out;
209
210 r = ch341_control_out(dev, 0xa1, 0, 0);
211 if (r < 0)
212 goto out;
213
214 r = ch341_set_baudrate(dev, priv);
215 if (r < 0)
216 goto out;
217
218 /* expect two bytes 0x56 0x00 */
219 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
220 if (r < 0)
221 goto out;
222
223 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
224 if (r < 0)
225 goto out;
226
227 /* expect 0xff 0xee */
228 r = ch341_get_status(dev, priv);
229 if (r < 0)
230 goto out;
231
232 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
233 if (r < 0)
234 goto out;
235
236 r = ch341_set_baudrate(dev, priv);
237 if (r < 0)
238 goto out;
239
240 r = ch341_set_handshake(dev, priv->line_control);
241 if (r < 0)
242 goto out;
243
244 /* expect 0x9f 0xee */
245 r = ch341_get_status(dev, priv);
246
247 out: kfree(buffer);
248 return r;
249 }
250
251 /* allocate private data */
ch341_attach(struct usb_serial * serial)252 static int ch341_attach(struct usb_serial *serial)
253 {
254 struct ch341_private *priv;
255 int r;
256
257 dbg("ch341_attach()");
258
259 /* private data */
260 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
261 if (!priv)
262 return -ENOMEM;
263
264 spin_lock_init(&priv->lock);
265 init_waitqueue_head(&priv->delta_msr_wait);
266 priv->baud_rate = DEFAULT_BAUD_RATE;
267 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
268
269 r = ch341_configure(serial->dev, priv);
270 if (r < 0)
271 goto error;
272
273 usb_set_serial_port_data(serial->port[0], priv);
274 return 0;
275
276 error: kfree(priv);
277 return r;
278 }
279
ch341_carrier_raised(struct usb_serial_port * port)280 static int ch341_carrier_raised(struct usb_serial_port *port)
281 {
282 struct ch341_private *priv = usb_get_serial_port_data(port);
283 if (priv->line_status & CH341_BIT_DCD)
284 return 1;
285 return 0;
286 }
287
ch341_dtr_rts(struct usb_serial_port * port,int on)288 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
289 {
290 struct ch341_private *priv = usb_get_serial_port_data(port);
291 unsigned long flags;
292
293 dbg("%s - port %d", __func__, port->number);
294 /* drop DTR and RTS */
295 spin_lock_irqsave(&priv->lock, flags);
296 if (on)
297 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
298 else
299 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
300 spin_unlock_irqrestore(&priv->lock, flags);
301 ch341_set_handshake(port->serial->dev, priv->line_control);
302 wake_up_interruptible(&priv->delta_msr_wait);
303 }
304
ch341_close(struct usb_serial_port * port)305 static void ch341_close(struct usb_serial_port *port)
306 {
307 dbg("%s - port %d", __func__, port->number);
308
309 usb_serial_generic_close(port);
310 usb_kill_urb(port->interrupt_in_urb);
311 }
312
313
314 /* open this device, set default parameters */
ch341_open(struct tty_struct * tty,struct usb_serial_port * port)315 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
316 {
317 struct usb_serial *serial = port->serial;
318 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
319 int r;
320
321 dbg("ch341_open()");
322
323 priv->baud_rate = DEFAULT_BAUD_RATE;
324
325 r = ch341_configure(serial->dev, priv);
326 if (r)
327 goto out;
328
329 r = ch341_set_handshake(serial->dev, priv->line_control);
330 if (r)
331 goto out;
332
333 r = ch341_set_baudrate(serial->dev, priv);
334 if (r)
335 goto out;
336
337 dbg("%s - submitting interrupt urb", __func__);
338 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
339 if (r) {
340 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
341 " error %d\n", __func__, r);
342 ch341_close(port);
343 goto out;
344 }
345
346 r = usb_serial_generic_open(tty, port);
347
348 out: return r;
349 }
350
351 /* Old_termios contains the original termios settings and
352 * tty->termios contains the new setting to be used.
353 */
ch341_set_termios(struct tty_struct * tty,struct usb_serial_port * port,struct ktermios * old_termios)354 static 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
361 dbg("ch341_set_termios()");
362
363 baud_rate = tty_get_baud_rate(tty);
364
365 priv->baud_rate = baud_rate;
366
367 if (baud_rate) {
368 spin_lock_irqsave(&priv->lock, flags);
369 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
370 spin_unlock_irqrestore(&priv->lock, flags);
371 ch341_set_baudrate(port->serial->dev, priv);
372 } else {
373 spin_lock_irqsave(&priv->lock, flags);
374 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
375 spin_unlock_irqrestore(&priv->lock, flags);
376 }
377
378 ch341_set_handshake(port->serial->dev, priv->line_control);
379
380 /* Unimplemented:
381 * (cflag & CSIZE) : data bits [5, 8]
382 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
383 * (cflag & CSTOPB) : stop bits [1, 2]
384 */
385 }
386
ch341_break_ctl(struct tty_struct * tty,int break_state)387 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
388 {
389 const uint16_t ch341_break_reg =
390 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
391 struct usb_serial_port *port = tty->driver_data;
392 int r;
393 uint16_t reg_contents;
394 uint8_t *break_reg;
395
396 dbg("%s()", __func__);
397
398 break_reg = kmalloc(2, GFP_KERNEL);
399 if (!break_reg) {
400 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
401 return;
402 }
403
404 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
405 ch341_break_reg, 0, break_reg, 2);
406 if (r < 0) {
407 dev_err(&port->dev, "%s - USB control read error (%d)\n",
408 __func__, r);
409 goto out;
410 }
411 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
412 __func__, break_reg[0], break_reg[1]);
413 if (break_state != 0) {
414 dbg("%s - Enter break state requested", __func__);
415 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
416 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
417 } else {
418 dbg("%s - Leave break state requested", __func__);
419 break_reg[0] |= CH341_NBREAK_BITS_REG1;
420 break_reg[1] |= CH341_NBREAK_BITS_REG2;
421 }
422 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
423 __func__, break_reg[0], break_reg[1]);
424 reg_contents = get_unaligned_le16(break_reg);
425 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
426 ch341_break_reg, reg_contents);
427 if (r < 0)
428 dev_err(&port->dev, "%s - USB control write error (%d)\n",
429 __func__, r);
430 out:
431 kfree(break_reg);
432 }
433
ch341_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)434 static int ch341_tiocmset(struct tty_struct *tty,
435 unsigned int set, unsigned int clear)
436 {
437 struct usb_serial_port *port = tty->driver_data;
438 struct ch341_private *priv = usb_get_serial_port_data(port);
439 unsigned long flags;
440 u8 control;
441
442 spin_lock_irqsave(&priv->lock, flags);
443 if (set & TIOCM_RTS)
444 priv->line_control |= CH341_BIT_RTS;
445 if (set & TIOCM_DTR)
446 priv->line_control |= CH341_BIT_DTR;
447 if (clear & TIOCM_RTS)
448 priv->line_control &= ~CH341_BIT_RTS;
449 if (clear & TIOCM_DTR)
450 priv->line_control &= ~CH341_BIT_DTR;
451 control = priv->line_control;
452 spin_unlock_irqrestore(&priv->lock, flags);
453
454 return ch341_set_handshake(port->serial->dev, control);
455 }
456
ch341_read_int_callback(struct urb * urb)457 static void ch341_read_int_callback(struct urb *urb)
458 {
459 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
460 unsigned char *data = urb->transfer_buffer;
461 unsigned int actual_length = urb->actual_length;
462 int status;
463
464 dbg("%s (%d)", __func__, port->number);
465
466 switch (urb->status) {
467 case 0:
468 /* success */
469 break;
470 case -ECONNRESET:
471 case -ENOENT:
472 case -ESHUTDOWN:
473 /* this urb is terminated, clean up */
474 dbg("%s - urb shutting down with status: %d", __func__,
475 urb->status);
476 return;
477 default:
478 dbg("%s - nonzero urb status received: %d", __func__,
479 urb->status);
480 goto exit;
481 }
482
483 usb_serial_debug_data(debug, &port->dev, __func__,
484 urb->actual_length, urb->transfer_buffer);
485
486 if (actual_length >= 4) {
487 struct ch341_private *priv = usb_get_serial_port_data(port);
488 unsigned long flags;
489 u8 prev_line_status = priv->line_status;
490
491 spin_lock_irqsave(&priv->lock, flags);
492 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
493 if ((data[1] & CH341_MULT_STAT))
494 priv->multi_status_change = 1;
495 spin_unlock_irqrestore(&priv->lock, flags);
496
497 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
498 struct tty_struct *tty = tty_port_tty_get(&port->port);
499 if (tty)
500 usb_serial_handle_dcd_change(port, tty,
501 priv->line_status & CH341_BIT_DCD);
502 tty_kref_put(tty);
503 }
504
505 wake_up_interruptible(&priv->delta_msr_wait);
506 }
507
508 exit:
509 status = usb_submit_urb(urb, GFP_ATOMIC);
510 if (status)
511 dev_err(&urb->dev->dev,
512 "%s - usb_submit_urb failed with result %d\n",
513 __func__, status);
514 }
515
wait_modem_info(struct usb_serial_port * port,unsigned int arg)516 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
517 {
518 struct ch341_private *priv = usb_get_serial_port_data(port);
519 unsigned long flags;
520 u8 prevstatus;
521 u8 status;
522 u8 changed;
523 u8 multi_change = 0;
524
525 spin_lock_irqsave(&priv->lock, flags);
526 prevstatus = priv->line_status;
527 priv->multi_status_change = 0;
528 spin_unlock_irqrestore(&priv->lock, flags);
529
530 while (!multi_change) {
531 interruptible_sleep_on(&priv->delta_msr_wait);
532 /* see if a signal did it */
533 if (signal_pending(current))
534 return -ERESTARTSYS;
535
536 spin_lock_irqsave(&priv->lock, flags);
537 status = priv->line_status;
538 multi_change = priv->multi_status_change;
539 spin_unlock_irqrestore(&priv->lock, flags);
540
541 changed = prevstatus ^ status;
542
543 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
544 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
545 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
546 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
547 return 0;
548 }
549 prevstatus = status;
550 }
551
552 return 0;
553 }
554
ch341_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)555 static int ch341_ioctl(struct tty_struct *tty,
556 unsigned int cmd, unsigned long arg)
557 {
558 struct usb_serial_port *port = tty->driver_data;
559 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
560
561 switch (cmd) {
562 case TIOCMIWAIT:
563 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
564 return wait_modem_info(port, arg);
565
566 default:
567 dbg("%s not supported = 0x%04x", __func__, cmd);
568 break;
569 }
570
571 return -ENOIOCTLCMD;
572 }
573
ch341_tiocmget(struct tty_struct * tty)574 static int ch341_tiocmget(struct tty_struct *tty)
575 {
576 struct usb_serial_port *port = tty->driver_data;
577 struct ch341_private *priv = usb_get_serial_port_data(port);
578 unsigned long flags;
579 u8 mcr;
580 u8 status;
581 unsigned int result;
582
583 dbg("%s (%d)", __func__, port->number);
584
585 spin_lock_irqsave(&priv->lock, flags);
586 mcr = priv->line_control;
587 status = priv->line_status;
588 spin_unlock_irqrestore(&priv->lock, flags);
589
590 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
591 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
592 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
593 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
594 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
595 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
596
597 dbg("%s - result = %x", __func__, result);
598
599 return result;
600 }
601
602
ch341_reset_resume(struct usb_interface * intf)603 static int ch341_reset_resume(struct usb_interface *intf)
604 {
605 struct usb_device *dev = interface_to_usbdev(intf);
606 struct usb_serial *serial = NULL;
607 struct ch341_private *priv;
608
609 serial = usb_get_intfdata(intf);
610 priv = usb_get_serial_port_data(serial->port[0]);
611
612 /*reconfigure ch341 serial port after bus-reset*/
613 ch341_configure(dev, priv);
614
615 usb_serial_resume(intf);
616
617 return 0;
618 }
619
620 static struct usb_driver ch341_driver = {
621 .name = "ch341",
622 .probe = usb_serial_probe,
623 .disconnect = usb_serial_disconnect,
624 .suspend = usb_serial_suspend,
625 .resume = usb_serial_resume,
626 .reset_resume = ch341_reset_resume,
627 .id_table = id_table,
628 .supports_autosuspend = 1,
629 };
630
631 static struct usb_serial_driver ch341_device = {
632 .driver = {
633 .owner = THIS_MODULE,
634 .name = "ch341-uart",
635 },
636 .id_table = id_table,
637 .num_ports = 1,
638 .open = ch341_open,
639 .dtr_rts = ch341_dtr_rts,
640 .carrier_raised = ch341_carrier_raised,
641 .close = ch341_close,
642 .ioctl = ch341_ioctl,
643 .set_termios = ch341_set_termios,
644 .break_ctl = ch341_break_ctl,
645 .tiocmget = ch341_tiocmget,
646 .tiocmset = ch341_tiocmset,
647 .read_int_callback = ch341_read_int_callback,
648 .attach = ch341_attach,
649 };
650
651 static struct usb_serial_driver * const serial_drivers[] = {
652 &ch341_device, NULL
653 };
654
655 module_usb_serial_driver(ch341_driver, serial_drivers);
656
657 MODULE_LICENSE("GPL");
658
659 module_param(debug, bool, S_IRUGO | S_IWUSR);
660 MODULE_PARM_DESC(debug, "Debug enabled or not");
661