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 | /* Break support - the information used to implement this was gleaned from |
52 | * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. |
53 | */ |
54 | |
55 | #define CH341_REQ_READ_VERSION 0x5F |
56 | #define CH341_REQ_WRITE_REG 0x9A |
57 | #define CH341_REQ_READ_REG 0x95 |
58 | #define CH341_REQ_SERIAL_INIT 0xA1 |
59 | #define CH341_REQ_MODEM_CTRL 0xA4 |
60 | |
61 | #define CH341_REG_BREAK 0x05 |
62 | #define CH341_REG_PRESCALER 0x12 |
63 | #define CH341_REG_DIVISOR 0x13 |
64 | #define CH341_REG_LCR 0x18 |
65 | #define CH341_REG_LCR2 0x25 |
66 | |
67 | #define CH341_NBREAK_BITS 0x01 |
68 | |
69 | #define CH341_LCR_ENABLE_RX 0x80 |
70 | #define CH341_LCR_ENABLE_TX 0x40 |
71 | #define CH341_LCR_MARK_SPACE 0x20 |
72 | #define CH341_LCR_PAR_EVEN 0x10 |
73 | #define CH341_LCR_ENABLE_PAR 0x08 |
74 | #define CH341_LCR_STOP_BITS_2 0x04 |
75 | #define CH341_LCR_CS8 0x03 |
76 | #define CH341_LCR_CS7 0x02 |
77 | #define CH341_LCR_CS6 0x01 |
78 | #define CH341_LCR_CS5 0x00 |
79 | |
80 | #define CH341_QUIRK_LIMITED_PRESCALER BIT(0) |
81 | #define CH341_QUIRK_SIMULATE_BREAK BIT(1) |
82 | |
83 | static const struct usb_device_id id_table[] = { |
84 | { USB_DEVICE(0x1a86, 0x5523) }, |
85 | { USB_DEVICE(0x1a86, 0x7522) }, |
86 | { USB_DEVICE(0x1a86, 0x7523) }, |
87 | { USB_DEVICE(0x2184, 0x0057) }, |
88 | { USB_DEVICE(0x4348, 0x5523) }, |
89 | { USB_DEVICE(0x9986, 0x7523) }, |
90 | { }, |
91 | }; |
92 | MODULE_DEVICE_TABLE(usb, id_table); |
93 | |
94 | struct ch341_private { |
95 | spinlock_t lock; /* access lock */ |
96 | unsigned baud_rate; /* set baud rate */ |
97 | u8 mcr; |
98 | u8 msr; |
99 | u8 lcr; |
100 | |
101 | unsigned long quirks; |
102 | u8 version; |
103 | |
104 | unsigned long break_end; |
105 | }; |
106 | |
107 | static void ch341_set_termios(struct tty_struct *tty, |
108 | struct usb_serial_port *port, |
109 | const struct ktermios *old_termios); |
110 | |
111 | static int ch341_control_out(struct usb_device *dev, u8 request, |
112 | u16 value, u16 index) |
113 | { |
114 | int r; |
115 | |
116 | dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n" , __func__, |
117 | request, value, index); |
118 | |
119 | r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, |
120 | USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, |
121 | value, index, NULL, size: 0, DEFAULT_TIMEOUT); |
122 | if (r < 0) |
123 | dev_err(&dev->dev, "failed to send control message: %d\n" , r); |
124 | |
125 | return r; |
126 | } |
127 | |
128 | static int ch341_control_in(struct usb_device *dev, |
129 | u8 request, u16 value, u16 index, |
130 | char *buf, unsigned bufsize) |
131 | { |
132 | int r; |
133 | |
134 | dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n" , __func__, |
135 | request, value, index, bufsize); |
136 | |
137 | r = usb_control_msg_recv(dev, endpoint: 0, request, |
138 | USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, |
139 | value, index, data: buf, size: bufsize, DEFAULT_TIMEOUT, |
140 | GFP_KERNEL); |
141 | if (r) { |
142 | dev_err(&dev->dev, "failed to receive control message: %d\n" , |
143 | r); |
144 | return r; |
145 | } |
146 | |
147 | return 0; |
148 | } |
149 | |
150 | #define CH341_CLKRATE 48000000 |
151 | #define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact))) |
152 | #define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512)) |
153 | |
154 | static const speed_t ch341_min_rates[] = { |
155 | CH341_MIN_RATE(0), |
156 | CH341_MIN_RATE(1), |
157 | CH341_MIN_RATE(2), |
158 | CH341_MIN_RATE(3), |
159 | }; |
160 | |
161 | /* Supported range is 46 to 3000000 bps. */ |
162 | #define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256) |
163 | #define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2)) |
164 | |
165 | /* |
166 | * The device line speed is given by the following equation: |
167 | * |
168 | * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where |
169 | * |
170 | * 0 <= ps <= 3, |
171 | * 0 <= fact <= 1, |
172 | * 2 <= div <= 256 if fact = 0, or |
173 | * 9 <= div <= 256 if fact = 1 |
174 | */ |
175 | static int ch341_get_divisor(struct ch341_private *priv, speed_t speed) |
176 | { |
177 | unsigned int fact, div, clk_div; |
178 | bool force_fact0 = false; |
179 | int ps; |
180 | |
181 | /* |
182 | * Clamp to supported range, this makes the (ps < 0) and (div < 2) |
183 | * sanity checks below redundant. |
184 | */ |
185 | speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS); |
186 | |
187 | /* |
188 | * Start with highest possible base clock (fact = 1) that will give a |
189 | * divisor strictly less than 512. |
190 | */ |
191 | fact = 1; |
192 | for (ps = 3; ps >= 0; ps--) { |
193 | if (speed > ch341_min_rates[ps]) |
194 | break; |
195 | } |
196 | |
197 | if (ps < 0) |
198 | return -EINVAL; |
199 | |
200 | /* Determine corresponding divisor, rounding down. */ |
201 | clk_div = CH341_CLK_DIV(ps, fact); |
202 | div = CH341_CLKRATE / (clk_div * speed); |
203 | |
204 | /* Some devices require a lower base clock if ps < 3. */ |
205 | if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER)) |
206 | force_fact0 = true; |
207 | |
208 | /* Halve base clock (fact = 0) if required. */ |
209 | if (div < 9 || div > 255 || force_fact0) { |
210 | div /= 2; |
211 | clk_div *= 2; |
212 | fact = 0; |
213 | } |
214 | |
215 | if (div < 2) |
216 | return -EINVAL; |
217 | |
218 | /* |
219 | * Pick next divisor if resulting rate is closer to the requested one, |
220 | * scale up to avoid rounding errors on low rates. |
221 | */ |
222 | if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >= |
223 | 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1))) |
224 | div++; |
225 | |
226 | /* |
227 | * Prefer lower base clock (fact = 0) if even divisor. |
228 | * |
229 | * Note that this makes the receiver more tolerant to errors. |
230 | */ |
231 | if (fact == 1 && div % 2 == 0) { |
232 | div /= 2; |
233 | fact = 0; |
234 | } |
235 | |
236 | return (0x100 - div) << 8 | fact << 2 | ps; |
237 | } |
238 | |
239 | static int ch341_set_baudrate_lcr(struct usb_device *dev, |
240 | struct ch341_private *priv, |
241 | speed_t baud_rate, u8 lcr) |
242 | { |
243 | int val; |
244 | int r; |
245 | |
246 | if (!baud_rate) |
247 | return -EINVAL; |
248 | |
249 | val = ch341_get_divisor(priv, speed: baud_rate); |
250 | if (val < 0) |
251 | return -EINVAL; |
252 | |
253 | /* |
254 | * CH341A buffers data until a full endpoint-size packet (32 bytes) |
255 | * has been received unless bit 7 is set. |
256 | * |
257 | * At least one device with version 0x27 appears to have this bit |
258 | * inverted. |
259 | */ |
260 | if (priv->version > 0x27) |
261 | val |= BIT(7); |
262 | |
263 | r = ch341_control_out(dev, CH341_REQ_WRITE_REG, |
264 | CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER, |
265 | index: val); |
266 | if (r) |
267 | return r; |
268 | |
269 | /* |
270 | * Chip versions before version 0x30 as read using |
271 | * CH341_REQ_READ_VERSION used separate registers for line control |
272 | * (stop bits, parity and word length). Version 0x30 and above use |
273 | * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero. |
274 | */ |
275 | if (priv->version < 0x30) |
276 | return 0; |
277 | |
278 | r = ch341_control_out(dev, CH341_REQ_WRITE_REG, |
279 | CH341_REG_LCR2 << 8 | CH341_REG_LCR, index: lcr); |
280 | if (r) |
281 | return r; |
282 | |
283 | return r; |
284 | } |
285 | |
286 | static int ch341_set_handshake(struct usb_device *dev, u8 control) |
287 | { |
288 | return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, value: ~control, index: 0); |
289 | } |
290 | |
291 | static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) |
292 | { |
293 | const unsigned int size = 2; |
294 | u8 buffer[2]; |
295 | int r; |
296 | unsigned long flags; |
297 | |
298 | r = ch341_control_in(dev, CH341_REQ_READ_REG, value: 0x0706, index: 0, buf: buffer, bufsize: size); |
299 | if (r) |
300 | return r; |
301 | |
302 | spin_lock_irqsave(&priv->lock, flags); |
303 | priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT; |
304 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
305 | |
306 | return 0; |
307 | } |
308 | |
309 | /* -------------------------------------------------------------------------- */ |
310 | |
311 | static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) |
312 | { |
313 | const unsigned int size = 2; |
314 | u8 buffer[2]; |
315 | int r; |
316 | |
317 | /* expect two bytes 0x27 0x00 */ |
318 | r = ch341_control_in(dev, CH341_REQ_READ_VERSION, value: 0, index: 0, buf: buffer, bufsize: size); |
319 | if (r) |
320 | return r; |
321 | |
322 | priv->version = buffer[0]; |
323 | dev_dbg(&dev->dev, "Chip version: 0x%02x\n" , priv->version); |
324 | |
325 | r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, value: 0, index: 0); |
326 | if (r < 0) |
327 | return r; |
328 | |
329 | r = ch341_set_baudrate_lcr(dev, priv, baud_rate: priv->baud_rate, lcr: priv->lcr); |
330 | if (r < 0) |
331 | return r; |
332 | |
333 | r = ch341_set_handshake(dev, control: priv->mcr); |
334 | if (r < 0) |
335 | return r; |
336 | |
337 | return 0; |
338 | } |
339 | |
340 | static int ch341_detect_quirks(struct usb_serial_port *port) |
341 | { |
342 | struct ch341_private *priv = usb_get_serial_port_data(port); |
343 | struct usb_device *udev = port->serial->dev; |
344 | const unsigned int size = 2; |
345 | unsigned long quirks = 0; |
346 | u8 buffer[2]; |
347 | int r; |
348 | |
349 | /* |
350 | * A subset of CH34x devices does not support all features. The |
351 | * prescaler is limited and there is no support for sending a RS232 |
352 | * break condition. A read failure when trying to set up the latter is |
353 | * used to detect these devices. |
354 | */ |
355 | r = usb_control_msg_recv(dev: udev, endpoint: 0, CH341_REQ_READ_REG, |
356 | USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, |
357 | CH341_REG_BREAK, index: 0, data: &buffer, size, |
358 | DEFAULT_TIMEOUT, GFP_KERNEL); |
359 | if (r == -EPIPE) { |
360 | dev_info(&port->dev, "break control not supported, using simulated break\n" ); |
361 | quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK; |
362 | r = 0; |
363 | } else if (r) { |
364 | dev_err(&port->dev, "failed to read break control: %d\n" , r); |
365 | } |
366 | |
367 | if (quirks) { |
368 | dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n" , quirks); |
369 | priv->quirks |= quirks; |
370 | } |
371 | |
372 | return r; |
373 | } |
374 | |
375 | static int ch341_port_probe(struct usb_serial_port *port) |
376 | { |
377 | struct ch341_private *priv; |
378 | int r; |
379 | |
380 | priv = kzalloc(size: sizeof(struct ch341_private), GFP_KERNEL); |
381 | if (!priv) |
382 | return -ENOMEM; |
383 | |
384 | spin_lock_init(&priv->lock); |
385 | priv->baud_rate = DEFAULT_BAUD_RATE; |
386 | /* |
387 | * Some CH340 devices appear unable to change the initial LCR |
388 | * settings, so set a sane 8N1 default. |
389 | */ |
390 | priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8; |
391 | |
392 | r = ch341_configure(dev: port->serial->dev, priv); |
393 | if (r < 0) |
394 | goto error; |
395 | |
396 | usb_set_serial_port_data(port, data: priv); |
397 | |
398 | r = ch341_detect_quirks(port); |
399 | if (r < 0) |
400 | goto error; |
401 | |
402 | return 0; |
403 | |
404 | error: kfree(objp: priv); |
405 | return r; |
406 | } |
407 | |
408 | static void ch341_port_remove(struct usb_serial_port *port) |
409 | { |
410 | struct ch341_private *priv; |
411 | |
412 | priv = usb_get_serial_port_data(port); |
413 | kfree(objp: priv); |
414 | } |
415 | |
416 | static int ch341_carrier_raised(struct usb_serial_port *port) |
417 | { |
418 | struct ch341_private *priv = usb_get_serial_port_data(port); |
419 | if (priv->msr & CH341_BIT_DCD) |
420 | return 1; |
421 | return 0; |
422 | } |
423 | |
424 | static void ch341_dtr_rts(struct usb_serial_port *port, int on) |
425 | { |
426 | struct ch341_private *priv = usb_get_serial_port_data(port); |
427 | unsigned long flags; |
428 | |
429 | /* drop DTR and RTS */ |
430 | spin_lock_irqsave(&priv->lock, flags); |
431 | if (on) |
432 | priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR; |
433 | else |
434 | priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR); |
435 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
436 | ch341_set_handshake(dev: port->serial->dev, control: priv->mcr); |
437 | } |
438 | |
439 | static void ch341_close(struct usb_serial_port *port) |
440 | { |
441 | usb_serial_generic_close(port); |
442 | usb_kill_urb(urb: port->interrupt_in_urb); |
443 | } |
444 | |
445 | |
446 | /* open this device, set default parameters */ |
447 | static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) |
448 | { |
449 | struct ch341_private *priv = usb_get_serial_port_data(port); |
450 | int r; |
451 | |
452 | if (tty) |
453 | ch341_set_termios(tty, port, NULL); |
454 | |
455 | dev_dbg(&port->dev, "%s - submitting interrupt urb\n" , __func__); |
456 | r = usb_submit_urb(urb: port->interrupt_in_urb, GFP_KERNEL); |
457 | if (r) { |
458 | dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n" , |
459 | __func__, r); |
460 | return r; |
461 | } |
462 | |
463 | r = ch341_get_status(dev: port->serial->dev, priv); |
464 | if (r < 0) { |
465 | dev_err(&port->dev, "failed to read modem status: %d\n" , r); |
466 | goto err_kill_interrupt_urb; |
467 | } |
468 | |
469 | r = usb_serial_generic_open(tty, port); |
470 | if (r) |
471 | goto err_kill_interrupt_urb; |
472 | |
473 | return 0; |
474 | |
475 | err_kill_interrupt_urb: |
476 | usb_kill_urb(urb: port->interrupt_in_urb); |
477 | |
478 | return r; |
479 | } |
480 | |
481 | /* Old_termios contains the original termios settings and |
482 | * tty->termios contains the new setting to be used. |
483 | */ |
484 | static void ch341_set_termios(struct tty_struct *tty, |
485 | struct usb_serial_port *port, |
486 | const struct ktermios *old_termios) |
487 | { |
488 | struct ch341_private *priv = usb_get_serial_port_data(port); |
489 | unsigned baud_rate; |
490 | unsigned long flags; |
491 | u8 lcr; |
492 | int r; |
493 | |
494 | /* redundant changes may cause the chip to lose bytes */ |
495 | if (old_termios && !tty_termios_hw_change(a: &tty->termios, b: old_termios)) |
496 | return; |
497 | |
498 | baud_rate = tty_get_baud_rate(tty); |
499 | |
500 | lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX; |
501 | |
502 | switch (C_CSIZE(tty)) { |
503 | case CS5: |
504 | lcr |= CH341_LCR_CS5; |
505 | break; |
506 | case CS6: |
507 | lcr |= CH341_LCR_CS6; |
508 | break; |
509 | case CS7: |
510 | lcr |= CH341_LCR_CS7; |
511 | break; |
512 | case CS8: |
513 | lcr |= CH341_LCR_CS8; |
514 | break; |
515 | } |
516 | |
517 | if (C_PARENB(tty)) { |
518 | lcr |= CH341_LCR_ENABLE_PAR; |
519 | if (C_PARODD(tty) == 0) |
520 | lcr |= CH341_LCR_PAR_EVEN; |
521 | if (C_CMSPAR(tty)) |
522 | lcr |= CH341_LCR_MARK_SPACE; |
523 | } |
524 | |
525 | if (C_CSTOPB(tty)) |
526 | lcr |= CH341_LCR_STOP_BITS_2; |
527 | |
528 | if (baud_rate) { |
529 | priv->baud_rate = baud_rate; |
530 | |
531 | r = ch341_set_baudrate_lcr(dev: port->serial->dev, priv, |
532 | baud_rate: priv->baud_rate, lcr); |
533 | if (r < 0 && old_termios) { |
534 | priv->baud_rate = tty_termios_baud_rate(termios: old_termios); |
535 | tty_termios_copy_hw(new: &tty->termios, old: old_termios); |
536 | } else if (r == 0) { |
537 | priv->lcr = lcr; |
538 | } |
539 | } |
540 | |
541 | spin_lock_irqsave(&priv->lock, flags); |
542 | if (C_BAUD(tty) == B0) |
543 | priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS); |
544 | else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) |
545 | priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS); |
546 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
547 | |
548 | ch341_set_handshake(dev: port->serial->dev, control: priv->mcr); |
549 | } |
550 | |
551 | /* |
552 | * A subset of all CH34x devices don't support a real break condition and |
553 | * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function |
554 | * simulates a break condition by lowering the baud rate to the minimum |
555 | * supported by the hardware upon enabling the break condition and sending |
556 | * a NUL byte. |
557 | * |
558 | * Incoming data is corrupted while the break condition is being simulated. |
559 | * |
560 | * Normally the duration of the break condition can be controlled individually |
561 | * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to |
562 | * TCSBRKP. Due to how the simulation is implemented the duration can't be |
563 | * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms. |
564 | */ |
565 | static int ch341_simulate_break(struct tty_struct *tty, int break_state) |
566 | { |
567 | struct usb_serial_port *port = tty->driver_data; |
568 | struct ch341_private *priv = usb_get_serial_port_data(port); |
569 | unsigned long now, delay; |
570 | int r, r2; |
571 | |
572 | if (break_state != 0) { |
573 | dev_dbg(&port->dev, "enter break state requested\n" ); |
574 | |
575 | r = ch341_set_baudrate_lcr(dev: port->serial->dev, priv, |
576 | CH341_MIN_BPS, |
577 | CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8); |
578 | if (r < 0) { |
579 | dev_err(&port->dev, |
580 | "failed to change baud rate to %u: %d\n" , |
581 | CH341_MIN_BPS, r); |
582 | goto restore; |
583 | } |
584 | |
585 | r = tty_put_char(tty, c: '\0'); |
586 | if (r < 0) { |
587 | dev_err(&port->dev, |
588 | "failed to write NUL byte for simulated break condition: %d\n" , |
589 | r); |
590 | goto restore; |
591 | } |
592 | |
593 | /* |
594 | * Compute expected transmission duration including safety |
595 | * margin. The original baud rate is only restored after the |
596 | * computed point in time. |
597 | * |
598 | * 11 bits = 1 start, 8 data, 1 stop, 1 margin |
599 | */ |
600 | priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS); |
601 | |
602 | return 0; |
603 | } |
604 | |
605 | dev_dbg(&port->dev, "leave break state requested\n" ); |
606 | |
607 | now = jiffies; |
608 | |
609 | if (time_before(now, priv->break_end)) { |
610 | /* Wait until NUL byte is written */ |
611 | delay = priv->break_end - now; |
612 | dev_dbg(&port->dev, |
613 | "wait %d ms while transmitting NUL byte at %u baud\n" , |
614 | jiffies_to_msecs(delay), CH341_MIN_BPS); |
615 | schedule_timeout_interruptible(timeout: delay); |
616 | } |
617 | |
618 | r = 0; |
619 | restore: |
620 | /* Restore original baud rate */ |
621 | r2 = ch341_set_baudrate_lcr(dev: port->serial->dev, priv, baud_rate: priv->baud_rate, |
622 | lcr: priv->lcr); |
623 | if (r2 < 0) { |
624 | dev_err(&port->dev, |
625 | "restoring original baud rate of %u failed: %d\n" , |
626 | priv->baud_rate, r2); |
627 | return r2; |
628 | } |
629 | |
630 | return r; |
631 | } |
632 | |
633 | static int ch341_break_ctl(struct tty_struct *tty, int break_state) |
634 | { |
635 | const uint16_t ch341_break_reg = |
636 | ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; |
637 | struct usb_serial_port *port = tty->driver_data; |
638 | struct ch341_private *priv = usb_get_serial_port_data(port); |
639 | int r; |
640 | uint16_t reg_contents; |
641 | uint8_t break_reg[2]; |
642 | |
643 | if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) |
644 | return ch341_simulate_break(tty, break_state); |
645 | |
646 | r = ch341_control_in(dev: port->serial->dev, CH341_REQ_READ_REG, |
647 | value: ch341_break_reg, index: 0, buf: break_reg, bufsize: 2); |
648 | if (r) { |
649 | dev_err(&port->dev, "%s - USB control read error (%d)\n" , |
650 | __func__, r); |
651 | if (r > 0) |
652 | r = -EIO; |
653 | return r; |
654 | } |
655 | dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n" , |
656 | __func__, break_reg[0], break_reg[1]); |
657 | if (break_state != 0) { |
658 | dev_dbg(&port->dev, "%s - Enter break state requested\n" , __func__); |
659 | break_reg[0] &= ~CH341_NBREAK_BITS; |
660 | break_reg[1] &= ~CH341_LCR_ENABLE_TX; |
661 | } else { |
662 | dev_dbg(&port->dev, "%s - Leave break state requested\n" , __func__); |
663 | break_reg[0] |= CH341_NBREAK_BITS; |
664 | break_reg[1] |= CH341_LCR_ENABLE_TX; |
665 | } |
666 | dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n" , |
667 | __func__, break_reg[0], break_reg[1]); |
668 | reg_contents = get_unaligned_le16(p: break_reg); |
669 | r = ch341_control_out(dev: port->serial->dev, CH341_REQ_WRITE_REG, |
670 | value: ch341_break_reg, index: reg_contents); |
671 | if (r < 0) { |
672 | dev_err(&port->dev, "%s - USB control write error (%d)\n" , |
673 | __func__, r); |
674 | return r; |
675 | } |
676 | |
677 | return 0; |
678 | } |
679 | |
680 | static int ch341_tiocmset(struct tty_struct *tty, |
681 | unsigned int set, unsigned int clear) |
682 | { |
683 | struct usb_serial_port *port = tty->driver_data; |
684 | struct ch341_private *priv = usb_get_serial_port_data(port); |
685 | unsigned long flags; |
686 | u8 control; |
687 | |
688 | spin_lock_irqsave(&priv->lock, flags); |
689 | if (set & TIOCM_RTS) |
690 | priv->mcr |= CH341_BIT_RTS; |
691 | if (set & TIOCM_DTR) |
692 | priv->mcr |= CH341_BIT_DTR; |
693 | if (clear & TIOCM_RTS) |
694 | priv->mcr &= ~CH341_BIT_RTS; |
695 | if (clear & TIOCM_DTR) |
696 | priv->mcr &= ~CH341_BIT_DTR; |
697 | control = priv->mcr; |
698 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
699 | |
700 | return ch341_set_handshake(dev: port->serial->dev, control); |
701 | } |
702 | |
703 | static void ch341_update_status(struct usb_serial_port *port, |
704 | unsigned char *data, size_t len) |
705 | { |
706 | struct ch341_private *priv = usb_get_serial_port_data(port); |
707 | struct tty_struct *tty; |
708 | unsigned long flags; |
709 | u8 status; |
710 | u8 delta; |
711 | |
712 | if (len < 4) |
713 | return; |
714 | |
715 | status = ~data[2] & CH341_BITS_MODEM_STAT; |
716 | |
717 | spin_lock_irqsave(&priv->lock, flags); |
718 | delta = status ^ priv->msr; |
719 | priv->msr = status; |
720 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
721 | |
722 | if (data[1] & CH341_MULT_STAT) |
723 | dev_dbg(&port->dev, "%s - multiple status change\n" , __func__); |
724 | |
725 | if (!delta) |
726 | return; |
727 | |
728 | if (delta & CH341_BIT_CTS) |
729 | port->icount.cts++; |
730 | if (delta & CH341_BIT_DSR) |
731 | port->icount.dsr++; |
732 | if (delta & CH341_BIT_RI) |
733 | port->icount.rng++; |
734 | if (delta & CH341_BIT_DCD) { |
735 | port->icount.dcd++; |
736 | tty = tty_port_tty_get(port: &port->port); |
737 | if (tty) { |
738 | usb_serial_handle_dcd_change(usb_port: port, tty, |
739 | status: status & CH341_BIT_DCD); |
740 | tty_kref_put(tty); |
741 | } |
742 | } |
743 | |
744 | wake_up_interruptible(&port->port.delta_msr_wait); |
745 | } |
746 | |
747 | static void ch341_read_int_callback(struct urb *urb) |
748 | { |
749 | struct usb_serial_port *port = urb->context; |
750 | unsigned char *data = urb->transfer_buffer; |
751 | unsigned int len = urb->actual_length; |
752 | int status; |
753 | |
754 | switch (urb->status) { |
755 | case 0: |
756 | /* success */ |
757 | break; |
758 | case -ECONNRESET: |
759 | case -ENOENT: |
760 | case -ESHUTDOWN: |
761 | /* this urb is terminated, clean up */ |
762 | dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n" , |
763 | __func__, urb->status); |
764 | return; |
765 | default: |
766 | dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n" , |
767 | __func__, urb->status); |
768 | goto exit; |
769 | } |
770 | |
771 | usb_serial_debug_data(dev: &port->dev, function: __func__, size: len, data); |
772 | ch341_update_status(port, data, len); |
773 | exit: |
774 | status = usb_submit_urb(urb, GFP_ATOMIC); |
775 | if (status) { |
776 | dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n" , |
777 | __func__, status); |
778 | } |
779 | } |
780 | |
781 | static int ch341_tiocmget(struct tty_struct *tty) |
782 | { |
783 | struct usb_serial_port *port = tty->driver_data; |
784 | struct ch341_private *priv = usb_get_serial_port_data(port); |
785 | unsigned long flags; |
786 | u8 mcr; |
787 | u8 status; |
788 | unsigned int result; |
789 | |
790 | spin_lock_irqsave(&priv->lock, flags); |
791 | mcr = priv->mcr; |
792 | status = priv->msr; |
793 | spin_unlock_irqrestore(lock: &priv->lock, flags); |
794 | |
795 | result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) |
796 | | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) |
797 | | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) |
798 | | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) |
799 | | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) |
800 | | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); |
801 | |
802 | dev_dbg(&port->dev, "%s - result = %x\n" , __func__, result); |
803 | |
804 | return result; |
805 | } |
806 | |
807 | static int ch341_reset_resume(struct usb_serial *serial) |
808 | { |
809 | struct usb_serial_port *port = serial->port[0]; |
810 | struct ch341_private *priv; |
811 | int ret; |
812 | |
813 | priv = usb_get_serial_port_data(port); |
814 | if (!priv) |
815 | return 0; |
816 | |
817 | /* reconfigure ch341 serial port after bus-reset */ |
818 | ch341_configure(dev: serial->dev, priv); |
819 | |
820 | if (tty_port_initialized(port: &port->port)) { |
821 | ret = usb_submit_urb(urb: port->interrupt_in_urb, GFP_NOIO); |
822 | if (ret) { |
823 | dev_err(&port->dev, "failed to submit interrupt urb: %d\n" , |
824 | ret); |
825 | return ret; |
826 | } |
827 | |
828 | ret = ch341_get_status(dev: port->serial->dev, priv); |
829 | if (ret < 0) { |
830 | dev_err(&port->dev, "failed to read modem status: %d\n" , |
831 | ret); |
832 | } |
833 | } |
834 | |
835 | return usb_serial_generic_resume(serial); |
836 | } |
837 | |
838 | static struct usb_serial_driver ch341_device = { |
839 | .driver = { |
840 | .owner = THIS_MODULE, |
841 | .name = "ch341-uart" , |
842 | }, |
843 | .id_table = id_table, |
844 | .num_ports = 1, |
845 | .open = ch341_open, |
846 | .dtr_rts = ch341_dtr_rts, |
847 | .carrier_raised = ch341_carrier_raised, |
848 | .close = ch341_close, |
849 | .set_termios = ch341_set_termios, |
850 | .break_ctl = ch341_break_ctl, |
851 | .tiocmget = ch341_tiocmget, |
852 | .tiocmset = ch341_tiocmset, |
853 | .tiocmiwait = usb_serial_generic_tiocmiwait, |
854 | .read_int_callback = ch341_read_int_callback, |
855 | .port_probe = ch341_port_probe, |
856 | .port_remove = ch341_port_remove, |
857 | .reset_resume = ch341_reset_resume, |
858 | }; |
859 | |
860 | static struct usb_serial_driver * const serial_drivers[] = { |
861 | &ch341_device, NULL |
862 | }; |
863 | |
864 | module_usb_serial_driver(serial_drivers, id_table); |
865 | |
866 | MODULE_LICENSE("GPL v2" ); |
867 | |