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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
28#define CH341_BIT_RTS (1 << 6)
29#define CH341_BIT_DTR (1 << 5)
30
31
32
33
34
35
36
37
38
39
40
41#define CH341_MULT_STAT 0x04
42
43
44
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
50
51
52
53
54#define CH341_BAUDBASE_FACTOR 1532620800
55#define CH341_BAUDBASE_DIVMAX 3
56
57
58
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;
92 unsigned 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
173
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
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
261
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
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
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
352
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
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 int ret;
494
495 if (len < 4)
496 return;
497
498 status = ~data[2] & CH341_BITS_MODEM_STAT;
499
500 spin_lock_irqsave(&priv->lock, flags);
501 delta = status ^ priv->msr;
502 priv->msr = status;
503 spin_unlock_irqrestore(&priv->lock, flags);
504
505 if (data[1] & CH341_MULT_STAT)
506 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
507
508 if (!delta)
509 return;
510
511 if (delta & CH341_BIT_CTS)
512 port->icount.cts++;
513 if (delta & CH341_BIT_DSR)
514 port->icount.dsr++;
515 if (delta & CH341_BIT_RI)
516 port->icount.rng++;
517 if (delta & CH341_BIT_DCD) {
518 port->icount.dcd++;
519 tty = tty_port_tty_get(&port->port);
520 if (tty) {
521 usb_serial_handle_dcd_change(port, tty,
522 status & CH341_BIT_DCD);
523 tty_kref_put(tty);
524 }
525
526 ret = ch341_get_status(port->serial->dev, priv);
527 if (ret < 0) {
528 dev_err(&port->dev, "failed to read modem status: %d\n",
529 ret);
530 }
531 }
532
533 wake_up_interruptible(&port->port.delta_msr_wait);
534}
535
536static void ch341_read_int_callback(struct urb *urb)
537{
538 struct usb_serial_port *port = urb->context;
539 unsigned char *data = urb->transfer_buffer;
540 unsigned int len = urb->actual_length;
541 int status;
542
543 switch (urb->status) {
544 case 0:
545
546 break;
547 case -ECONNRESET:
548 case -ENOENT:
549 case -ESHUTDOWN:
550
551 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
552 __func__, urb->status);
553 return;
554 default:
555 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
556 __func__, urb->status);
557 goto exit;
558 }
559
560 usb_serial_debug_data(&port->dev, __func__, len, data);
561 ch341_update_status(port, data, len);
562exit:
563 status = usb_submit_urb(urb, GFP_ATOMIC);
564 if (status) {
565 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
566 __func__, status);
567 }
568}
569
570static int ch341_tiocmget(struct tty_struct *tty)
571{
572 struct usb_serial_port *port = tty->driver_data;
573 struct ch341_private *priv = usb_get_serial_port_data(port);
574 unsigned long flags;
575 u8 mcr;
576 u8 status;
577 unsigned int result;
578
579 spin_lock_irqsave(&priv->lock, flags);
580 mcr = priv->mcr;
581 status = priv->msr;
582 spin_unlock_irqrestore(&priv->lock, flags);
583
584 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
585 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
586 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
587 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
588 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
589 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
590
591 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
592
593 return result;
594}
595
596static int ch341_reset_resume(struct usb_serial *serial)
597{
598 struct ch341_private *priv;
599
600 priv = usb_get_serial_port_data(serial->port[0]);
601
602
603 ch341_configure(serial->dev, priv);
604
605 return 0;
606}
607
608static struct usb_serial_driver ch341_device = {
609 .driver = {
610 .owner = THIS_MODULE,
611 .name = "ch341-uart",
612 },
613 .id_table = id_table,
614 .num_ports = 1,
615 .open = ch341_open,
616 .dtr_rts = ch341_dtr_rts,
617 .carrier_raised = ch341_carrier_raised,
618 .close = ch341_close,
619 .set_termios = ch341_set_termios,
620 .break_ctl = ch341_break_ctl,
621 .tiocmget = ch341_tiocmget,
622 .tiocmset = ch341_tiocmset,
623 .tiocmiwait = usb_serial_generic_tiocmiwait,
624 .read_int_callback = ch341_read_int_callback,
625 .port_probe = ch341_port_probe,
626 .port_remove = ch341_port_remove,
627 .reset_resume = ch341_reset_resume,
628};
629
630static struct usb_serial_driver * const serial_drivers[] = {
631 &ch341_device, NULL
632};
633
634module_usb_serial_driver(serial_drivers, id_table);
635
636MODULE_LICENSE("GPL v2");
637
