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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
32#define CH341_BIT_RTS (1 << 6)
33#define CH341_BIT_DTR (1 << 5)
34
35
36
37
38
39
40
41
42
43
44
45#define CH341_MULT_STAT 0x04
46
47
48
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
54
55
56
57
58#define CH341_BAUDBASE_FACTOR 1532620800
59#define CH341_BAUDBASE_DIVMAX 3
60
61
62
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 const struct usb_device_id id_table[] = {
74 { USB_DEVICE(0x4348, 0x5523) },
75 { USB_DEVICE(0x1a86, 0x7523) },
76 { USB_DEVICE(0x1a86, 0x5523) },
77 { },
78};
79MODULE_DEVICE_TABLE(usb, id_table);
80
81struct ch341_private {
82 spinlock_t lock;
83 unsigned baud_rate;
84 u8 line_control;
85 u8 line_status;
86 u8 multi_status_change;
87};
88
89static int ch341_control_out(struct usb_device *dev, u8 request,
90 u16 value, u16 index)
91{
92 int r;
93
94 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
95 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
96
97 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
98 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
99 value, index, NULL, 0, DEFAULT_TIMEOUT);
100
101 return r;
102}
103
104static int ch341_control_in(struct usb_device *dev,
105 u8 request, u16 value, u16 index,
106 char *buf, unsigned bufsize)
107{
108 int r;
109
110 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
111 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
112 (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
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
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
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
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
238 r = ch341_get_status(dev, priv);
239
240out: kfree(buffer);
241 return r;
242}
243
244static int ch341_port_probe(struct usb_serial_port *port)
245{
246 struct ch341_private *priv;
247 int r;
248
249 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
250 if (!priv)
251 return -ENOMEM;
252
253 spin_lock_init(&priv->lock);
254 priv->baud_rate = DEFAULT_BAUD_RATE;
255 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
256
257 r = ch341_configure(port->serial->dev, priv);
258 if (r < 0)
259 goto error;
260
261 usb_set_serial_port_data(port, priv);
262 return 0;
263
264error: kfree(priv);
265 return r;
266}
267
268static int ch341_port_remove(struct usb_serial_port *port)
269{
270 struct ch341_private *priv;
271
272 priv = usb_get_serial_port_data(port);
273 kfree(priv);
274
275 return 0;
276}
277
278static int ch341_carrier_raised(struct usb_serial_port *port)
279{
280 struct ch341_private *priv = usb_get_serial_port_data(port);
281 if (priv->line_status & CH341_BIT_DCD)
282 return 1;
283 return 0;
284}
285
286static void ch341_dtr_rts(struct usb_serial_port *port, int on)
287{
288 struct ch341_private *priv = usb_get_serial_port_data(port);
289 unsigned long flags;
290
291
292 spin_lock_irqsave(&priv->lock, flags);
293 if (on)
294 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
295 else
296 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
297 spin_unlock_irqrestore(&priv->lock, flags);
298 ch341_set_handshake(port->serial->dev, priv->line_control);
299}
300
301static void ch341_close(struct usb_serial_port *port)
302{
303 usb_serial_generic_close(port);
304 usb_kill_urb(port->interrupt_in_urb);
305}
306
307
308
309static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
310{
311 struct usb_serial *serial = port->serial;
312 struct ch341_private *priv = usb_get_serial_port_data(port);
313 int r;
314
315 priv->baud_rate = DEFAULT_BAUD_RATE;
316
317 r = ch341_configure(serial->dev, priv);
318 if (r)
319 goto out;
320
321 r = ch341_set_handshake(serial->dev, priv->line_control);
322 if (r)
323 goto out;
324
325 r = ch341_set_baudrate(serial->dev, priv);
326 if (r)
327 goto out;
328
329 dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
330 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
331 if (r) {
332 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
333 " error %d\n", __func__, r);
334 ch341_close(port);
335 goto out;
336 }
337
338 r = usb_serial_generic_open(tty, port);
339
340out: return r;
341}
342
343
344
345
346static void ch341_set_termios(struct tty_struct *tty,
347 struct usb_serial_port *port, struct ktermios *old_termios)
348{
349 struct ch341_private *priv = usb_get_serial_port_data(port);
350 unsigned baud_rate;
351 unsigned long flags;
352
353 baud_rate = tty_get_baud_rate(tty);
354
355 priv->baud_rate = baud_rate;
356
357 if (baud_rate) {
358 spin_lock_irqsave(&priv->lock, flags);
359 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
360 spin_unlock_irqrestore(&priv->lock, flags);
361 ch341_set_baudrate(port->serial->dev, priv);
362 } else {
363 spin_lock_irqsave(&priv->lock, flags);
364 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
365 spin_unlock_irqrestore(&priv->lock, flags);
366 }
367
368 ch341_set_handshake(port->serial->dev, priv->line_control);
369
370
371
372
373
374
375}
376
377static void ch341_break_ctl(struct tty_struct *tty, int break_state)
378{
379 const uint16_t ch341_break_reg =
380 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
381 struct usb_serial_port *port = tty->driver_data;
382 int r;
383 uint16_t reg_contents;
384 uint8_t *break_reg;
385
386 break_reg = kmalloc(2, GFP_KERNEL);
387 if (!break_reg) {
388 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
389 return;
390 }
391
392 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
393 ch341_break_reg, 0, break_reg, 2);
394 if (r < 0) {
395 dev_err(&port->dev, "%s - USB control read error (%d)\n",
396 __func__, r);
397 goto out;
398 }
399 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
400 __func__, break_reg[0], break_reg[1]);
401 if (break_state != 0) {
402 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
403 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
404 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
405 } else {
406 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
407 break_reg[0] |= CH341_NBREAK_BITS_REG1;
408 break_reg[1] |= CH341_NBREAK_BITS_REG2;
409 }
410 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
411 __func__, break_reg[0], break_reg[1]);
412 reg_contents = get_unaligned_le16(break_reg);
413 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
414 ch341_break_reg, reg_contents);
415 if (r < 0)
416 dev_err(&port->dev, "%s - USB control write error (%d)\n",
417 __func__, r);
418out:
419 kfree(break_reg);
420}
421
422static int ch341_tiocmset(struct tty_struct *tty,
423 unsigned int set, unsigned int clear)
424{
425 struct usb_serial_port *port = tty->driver_data;
426 struct ch341_private *priv = usb_get_serial_port_data(port);
427 unsigned long flags;
428 u8 control;
429
430 spin_lock_irqsave(&priv->lock, flags);
431 if (set & TIOCM_RTS)
432 priv->line_control |= CH341_BIT_RTS;
433 if (set & TIOCM_DTR)
434 priv->line_control |= CH341_BIT_DTR;
435 if (clear & TIOCM_RTS)
436 priv->line_control &= ~CH341_BIT_RTS;
437 if (clear & TIOCM_DTR)
438 priv->line_control &= ~CH341_BIT_DTR;
439 control = priv->line_control;
440 spin_unlock_irqrestore(&priv->lock, flags);
441
442 return ch341_set_handshake(port->serial->dev, control);
443}
444
445static void ch341_read_int_callback(struct urb *urb)
446{
447 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
448 unsigned char *data = urb->transfer_buffer;
449 unsigned int actual_length = urb->actual_length;
450 int status;
451
452 switch (urb->status) {
453 case 0:
454
455 break;
456 case -ECONNRESET:
457 case -ENOENT:
458 case -ESHUTDOWN:
459
460 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
461 __func__, urb->status);
462 return;
463 default:
464 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
465 __func__, urb->status);
466 goto exit;
467 }
468
469 usb_serial_debug_data(&port->dev, __func__,
470 urb->actual_length, urb->transfer_buffer);
471
472 if (actual_length >= 4) {
473 struct ch341_private *priv = usb_get_serial_port_data(port);
474 unsigned long flags;
475 u8 prev_line_status = priv->line_status;
476
477 spin_lock_irqsave(&priv->lock, flags);
478 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
479 if ((data[1] & CH341_MULT_STAT))
480 priv->multi_status_change = 1;
481 spin_unlock_irqrestore(&priv->lock, flags);
482
483 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
484 struct tty_struct *tty = tty_port_tty_get(&port->port);
485 if (tty)
486 usb_serial_handle_dcd_change(port, tty,
487 priv->line_status & CH341_BIT_DCD);
488 tty_kref_put(tty);
489 }
490
491 wake_up_interruptible(&port->port.delta_msr_wait);
492 }
493
494exit:
495 status = usb_submit_urb(urb, GFP_ATOMIC);
496 if (status)
497 dev_err(&urb->dev->dev,
498 "%s - usb_submit_urb failed with result %d\n",
499 __func__, status);
500}
501
502static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
503{
504 struct usb_serial_port *port = tty->driver_data;
505 struct ch341_private *priv = usb_get_serial_port_data(port);
506 unsigned long flags;
507 u8 prevstatus;
508 u8 status;
509 u8 changed;
510 u8 multi_change = 0;
511
512 spin_lock_irqsave(&priv->lock, flags);
513 prevstatus = priv->line_status;
514 priv->multi_status_change = 0;
515 spin_unlock_irqrestore(&priv->lock, flags);
516
517 while (!multi_change) {
518 interruptible_sleep_on(&port->port.delta_msr_wait);
519
520 if (signal_pending(current))
521 return -ERESTARTSYS;
522
523 if (port->serial->disconnected)
524 return -EIO;
525
526 spin_lock_irqsave(&priv->lock, flags);
527 status = priv->line_status;
528 multi_change = priv->multi_status_change;
529 spin_unlock_irqrestore(&priv->lock, flags);
530
531 changed = prevstatus ^ status;
532
533 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
534 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
535 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
536 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
537 return 0;
538 }
539 prevstatus = status;
540 }
541
542 return 0;
543}
544
545static int ch341_tiocmget(struct tty_struct *tty)
546{
547 struct usb_serial_port *port = tty->driver_data;
548 struct ch341_private *priv = usb_get_serial_port_data(port);
549 unsigned long flags;
550 u8 mcr;
551 u8 status;
552 unsigned int result;
553
554 spin_lock_irqsave(&priv->lock, flags);
555 mcr = priv->line_control;
556 status = priv->line_status;
557 spin_unlock_irqrestore(&priv->lock, flags);
558
559 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
560 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
561 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
562 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
563 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
564 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
565
566 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
567
568 return result;
569}
570
571static int ch341_reset_resume(struct usb_serial *serial)
572{
573 struct ch341_private *priv;
574
575 priv = usb_get_serial_port_data(serial->port[0]);
576
577
578 ch341_configure(serial->dev, priv);
579
580 return 0;
581}
582
583static struct usb_serial_driver ch341_device = {
584 .driver = {
585 .owner = THIS_MODULE,
586 .name = "ch341-uart",
587 },
588 .id_table = id_table,
589 .num_ports = 1,
590 .open = ch341_open,
591 .dtr_rts = ch341_dtr_rts,
592 .carrier_raised = ch341_carrier_raised,
593 .close = ch341_close,
594 .set_termios = ch341_set_termios,
595 .break_ctl = ch341_break_ctl,
596 .tiocmget = ch341_tiocmget,
597 .tiocmset = ch341_tiocmset,
598 .tiocmiwait = ch341_tiocmiwait,
599 .read_int_callback = ch341_read_int_callback,
600 .port_probe = ch341_port_probe,
601 .port_remove = ch341_port_remove,
602 .reset_resume = ch341_reset_resume,
603};
604
605static struct usb_serial_driver * const serial_drivers[] = {
606 &ch341_device, NULL
607};
608
609module_usb_serial_driver(serial_drivers, id_table);
610
611MODULE_LICENSE("GPL");
612