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_READ_VERSION 0x5F 65 #define CH341_REQ_WRITE_REG 0x9A 66 #define CH341_REQ_READ_REG 0x95 67 #define CH341_REQ_SERIAL_INIT 0xA1 68 #define CH341_REQ_MODEM_CTRL 0xA4 69 70 #define CH341_REG_BREAK 0x05 71 #define CH341_REG_LCR 0x18 72 #define CH341_NBREAK_BITS 0x01 73 74 #define CH341_LCR_ENABLE_RX 0x80 75 #define CH341_LCR_ENABLE_TX 0x40 76 #define CH341_LCR_MARK_SPACE 0x20 77 #define CH341_LCR_PAR_EVEN 0x10 78 #define CH341_LCR_ENABLE_PAR 0x08 79 #define CH341_LCR_STOP_BITS_2 0x04 80 #define CH341_LCR_CS8 0x03 81 #define CH341_LCR_CS7 0x02 82 #define CH341_LCR_CS6 0x01 83 #define CH341_LCR_CS5 0x00 84 85 static const struct usb_device_id id_table[] = { 86 { USB_DEVICE(0x4348, 0x5523) }, 87 { USB_DEVICE(0x1a86, 0x7523) }, 88 { USB_DEVICE(0x1a86, 0x5523) }, 89 { }, 90 }; 91 MODULE_DEVICE_TABLE(usb, id_table); 92 93 struct ch341_private { 94 spinlock_t lock; /* access lock */ 95 unsigned baud_rate; /* set baud rate */ 96 u8 line_control; /* set line control value RTS/DTR */ 97 u8 line_status; /* active status of modem control inputs */ 98 u8 lcr; 99 }; 100 101 static void ch341_set_termios(struct tty_struct *tty, 102 struct usb_serial_port *port, 103 struct ktermios *old_termios); 104 105 static int ch341_control_out(struct usb_device *dev, u8 request, 106 u16 value, u16 index) 107 { 108 int r; 109 110 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n", 111 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); 112 113 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 114 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 115 value, index, NULL, 0, DEFAULT_TIMEOUT); 116 if (r < 0) 117 dev_err(&dev->dev, "failed to send control message: %d\n", r); 118 119 return r; 120 } 121 122 static int ch341_control_in(struct usb_device *dev, 123 u8 request, u16 value, u16 index, 124 char *buf, unsigned bufsize) 125 { 126 int r; 127 128 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n", 129 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, 130 (int)bufsize); 131 132 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 133 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 134 value, index, buf, bufsize, DEFAULT_TIMEOUT); 135 if (r < bufsize) { 136 if (r >= 0) { 137 dev_err(&dev->dev, 138 "short control message received (%d < %u)\n", 139 r, bufsize); 140 r = -EIO; 141 } 142 143 dev_err(&dev->dev, "failed to receive control message: %d\n", 144 r); 145 return r; 146 } 147 148 return 0; 149 } 150 151 static int ch341_set_baudrate_lcr(struct usb_device *dev, 152 struct ch341_private *priv, u8 lcr) 153 { 154 short a; 155 int r; 156 unsigned long factor; 157 short divisor; 158 159 if (!priv->baud_rate) 160 return -EINVAL; 161 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 162 divisor = CH341_BAUDBASE_DIVMAX; 163 164 while ((factor > 0xfff0) && divisor) { 165 factor >>= 3; 166 divisor--; 167 } 168 169 if (factor > 0xfff0) 170 return -EINVAL; 171 172 factor = 0x10000 - factor; 173 a = (factor & 0xff00) | divisor; 174 175 /* 176 * CH341A buffers data until a full endpoint-size packet (32 bytes) 177 * has been received unless bit 7 is set. 178 */ 179 a |= BIT(7); 180 181 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a); 182 if (r) 183 return r; 184 185 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr); 186 if (r) 187 return r; 188 189 return r; 190 } 191 192 static int ch341_set_handshake(struct usb_device *dev, u8 control) 193 { 194 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0); 195 } 196 197 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 198 { 199 const unsigned int size = 2; 200 char *buffer; 201 int r; 202 unsigned long flags; 203 204 buffer = kmalloc(size, GFP_KERNEL); 205 if (!buffer) 206 return -ENOMEM; 207 208 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size); 209 if (r < 0) 210 goto out; 211 212 spin_lock_irqsave(&priv->lock, flags); 213 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 214 spin_unlock_irqrestore(&priv->lock, flags); 215 216 out: kfree(buffer); 217 return r; 218 } 219 220 /* -------------------------------------------------------------------------- */ 221 222 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 223 { 224 const unsigned int size = 2; 225 char *buffer; 226 int r; 227 228 buffer = kmalloc(size, GFP_KERNEL); 229 if (!buffer) 230 return -ENOMEM; 231 232 /* expect two bytes 0x27 0x00 */ 233 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size); 234 if (r < 0) 235 goto out; 236 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]); 237 238 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0); 239 if (r < 0) 240 goto out; 241 242 /* expect two bytes 0x56 0x00 */ 243 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size); 244 if (r < 0) 245 goto out; 246 247 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050); 248 if (r < 0) 249 goto out; 250 251 /* expect 0xff 0xee */ 252 r = ch341_get_status(dev, priv); 253 if (r < 0) 254 goto out; 255 256 r = ch341_set_baudrate_lcr(dev, priv, priv->lcr); 257 if (r < 0) 258 goto out; 259 260 r = ch341_set_handshake(dev, priv->line_control); 261 if (r < 0) 262 goto out; 263 264 /* expect 0x9f 0xee */ 265 r = ch341_get_status(dev, priv); 266 267 out: kfree(buffer); 268 return r; 269 } 270 271 static int ch341_port_probe(struct usb_serial_port *port) 272 { 273 struct ch341_private *priv; 274 int r; 275 276 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 277 if (!priv) 278 return -ENOMEM; 279 280 spin_lock_init(&priv->lock); 281 priv->baud_rate = DEFAULT_BAUD_RATE; 282 283 r = ch341_configure(port->serial->dev, priv); 284 if (r < 0) 285 goto error; 286 287 usb_set_serial_port_data(port, priv); 288 return 0; 289 290 error: kfree(priv); 291 return r; 292 } 293 294 static int ch341_port_remove(struct usb_serial_port *port) 295 { 296 struct ch341_private *priv; 297 298 priv = usb_get_serial_port_data(port); 299 kfree(priv); 300 301 return 0; 302 } 303 304 static int ch341_carrier_raised(struct usb_serial_port *port) 305 { 306 struct ch341_private *priv = usb_get_serial_port_data(port); 307 if (priv->line_status & CH341_BIT_DCD) 308 return 1; 309 return 0; 310 } 311 312 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 313 { 314 struct ch341_private *priv = usb_get_serial_port_data(port); 315 unsigned long flags; 316 317 /* drop DTR and RTS */ 318 spin_lock_irqsave(&priv->lock, flags); 319 if (on) 320 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 321 else 322 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 323 spin_unlock_irqrestore(&priv->lock, flags); 324 ch341_set_handshake(port->serial->dev, priv->line_control); 325 } 326 327 static void ch341_close(struct usb_serial_port *port) 328 { 329 usb_serial_generic_close(port); 330 usb_kill_urb(port->interrupt_in_urb); 331 } 332 333 334 /* open this device, set default parameters */ 335 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 336 { 337 struct usb_serial *serial = port->serial; 338 struct ch341_private *priv = usb_get_serial_port_data(port); 339 int r; 340 341 r = ch341_configure(serial->dev, priv); 342 if (r) 343 return r; 344 345 if (tty) 346 ch341_set_termios(tty, port, NULL); 347 348 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); 349 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 350 if (r) { 351 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", 352 __func__, r); 353 return r; 354 } 355 356 r = usb_serial_generic_open(tty, port); 357 if (r) 358 goto err_kill_interrupt_urb; 359 360 return 0; 361 362 err_kill_interrupt_urb: 363 usb_kill_urb(port->interrupt_in_urb); 364 365 return r; 366 } 367 368 /* Old_termios contains the original termios settings and 369 * tty->termios contains the new setting to be used. 370 */ 371 static void ch341_set_termios(struct tty_struct *tty, 372 struct usb_serial_port *port, struct ktermios *old_termios) 373 { 374 struct ch341_private *priv = usb_get_serial_port_data(port); 375 unsigned baud_rate; 376 unsigned long flags; 377 unsigned char ctrl; 378 int r; 379 380 /* redundant changes may cause the chip to lose bytes */ 381 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) 382 return; 383 384 baud_rate = tty_get_baud_rate(tty); 385 386 ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX; 387 388 switch (C_CSIZE(tty)) { 389 case CS5: 390 ctrl |= CH341_LCR_CS5; 391 break; 392 case CS6: 393 ctrl |= CH341_LCR_CS6; 394 break; 395 case CS7: 396 ctrl |= CH341_LCR_CS7; 397 break; 398 case CS8: 399 ctrl |= CH341_LCR_CS8; 400 break; 401 } 402 403 if (C_PARENB(tty)) { 404 ctrl |= CH341_LCR_ENABLE_PAR; 405 if (C_PARODD(tty) == 0) 406 ctrl |= CH341_LCR_PAR_EVEN; 407 if (C_CMSPAR(tty)) 408 ctrl |= CH341_LCR_MARK_SPACE; 409 } 410 411 if (C_CSTOPB(tty)) 412 ctrl |= CH341_LCR_STOP_BITS_2; 413 414 if (baud_rate) { 415 priv->baud_rate = baud_rate; 416 417 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl); 418 if (r < 0 && old_termios) { 419 priv->baud_rate = tty_termios_baud_rate(old_termios); 420 tty_termios_copy_hw(&tty->termios, old_termios); 421 } else if (r == 0) { 422 priv->lcr = ctrl; 423 } 424 } 425 426 spin_lock_irqsave(&priv->lock, flags); 427 if (C_BAUD(tty) == B0) 428 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 429 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) 430 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 431 spin_unlock_irqrestore(&priv->lock, flags); 432 433 ch341_set_handshake(port->serial->dev, priv->line_control); 434 } 435 436 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 437 { 438 const uint16_t ch341_break_reg = 439 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; 440 struct usb_serial_port *port = tty->driver_data; 441 int r; 442 uint16_t reg_contents; 443 uint8_t *break_reg; 444 445 break_reg = kmalloc(2, GFP_KERNEL); 446 if (!break_reg) 447 return; 448 449 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 450 ch341_break_reg, 0, break_reg, 2); 451 if (r < 0) { 452 dev_err(&port->dev, "%s - USB control read error (%d)\n", 453 __func__, r); 454 goto out; 455 } 456 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 457 __func__, break_reg[0], break_reg[1]); 458 if (break_state != 0) { 459 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 460 break_reg[0] &= ~CH341_NBREAK_BITS; 461 break_reg[1] &= ~CH341_LCR_ENABLE_TX; 462 } else { 463 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 464 break_reg[0] |= CH341_NBREAK_BITS; 465 break_reg[1] |= CH341_LCR_ENABLE_TX; 466 } 467 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 468 __func__, break_reg[0], break_reg[1]); 469 reg_contents = get_unaligned_le16(break_reg); 470 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 471 ch341_break_reg, reg_contents); 472 if (r < 0) 473 dev_err(&port->dev, "%s - USB control write error (%d)\n", 474 __func__, r); 475 out: 476 kfree(break_reg); 477 } 478 479 static int ch341_tiocmset(struct tty_struct *tty, 480 unsigned int set, unsigned int clear) 481 { 482 struct usb_serial_port *port = tty->driver_data; 483 struct ch341_private *priv = usb_get_serial_port_data(port); 484 unsigned long flags; 485 u8 control; 486 487 spin_lock_irqsave(&priv->lock, flags); 488 if (set & TIOCM_RTS) 489 priv->line_control |= CH341_BIT_RTS; 490 if (set & TIOCM_DTR) 491 priv->line_control |= CH341_BIT_DTR; 492 if (clear & TIOCM_RTS) 493 priv->line_control &= ~CH341_BIT_RTS; 494 if (clear & TIOCM_DTR) 495 priv->line_control &= ~CH341_BIT_DTR; 496 control = priv->line_control; 497 spin_unlock_irqrestore(&priv->lock, flags); 498 499 return ch341_set_handshake(port->serial->dev, control); 500 } 501 502 static void ch341_update_line_status(struct usb_serial_port *port, 503 unsigned char *data, size_t len) 504 { 505 struct ch341_private *priv = usb_get_serial_port_data(port); 506 struct tty_struct *tty; 507 unsigned long flags; 508 u8 status; 509 u8 delta; 510 511 if (len < 4) 512 return; 513 514 status = ~data[2] & CH341_BITS_MODEM_STAT; 515 516 spin_lock_irqsave(&priv->lock, flags); 517 delta = status ^ priv->line_status; 518 priv->line_status = status; 519 spin_unlock_irqrestore(&priv->lock, flags); 520 521 if (data[1] & CH341_MULT_STAT) 522 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 523 524 if (!delta) 525 return; 526 527 if (delta & CH341_BIT_CTS) 528 port->icount.cts++; 529 if (delta & CH341_BIT_DSR) 530 port->icount.dsr++; 531 if (delta & CH341_BIT_RI) 532 port->icount.rng++; 533 if (delta & CH341_BIT_DCD) { 534 port->icount.dcd++; 535 tty = tty_port_tty_get(&port->port); 536 if (tty) { 537 usb_serial_handle_dcd_change(port, tty, 538 status & CH341_BIT_DCD); 539 tty_kref_put(tty); 540 } 541 } 542 543 wake_up_interruptible(&port->port.delta_msr_wait); 544 } 545 546 static void ch341_read_int_callback(struct urb *urb) 547 { 548 struct usb_serial_port *port = urb->context; 549 unsigned char *data = urb->transfer_buffer; 550 unsigned int len = urb->actual_length; 551 int status; 552 553 switch (urb->status) { 554 case 0: 555 /* success */ 556 break; 557 case -ECONNRESET: 558 case -ENOENT: 559 case -ESHUTDOWN: 560 /* this urb is terminated, clean up */ 561 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 562 __func__, urb->status); 563 return; 564 default: 565 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 566 __func__, urb->status); 567 goto exit; 568 } 569 570 usb_serial_debug_data(&port->dev, __func__, len, data); 571 ch341_update_line_status(port, data, len); 572 exit: 573 status = usb_submit_urb(urb, GFP_ATOMIC); 574 if (status) { 575 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 576 __func__, status); 577 } 578 } 579 580 static int ch341_tiocmget(struct tty_struct *tty) 581 { 582 struct usb_serial_port *port = tty->driver_data; 583 struct ch341_private *priv = usb_get_serial_port_data(port); 584 unsigned long flags; 585 u8 mcr; 586 u8 status; 587 unsigned int result; 588 589 spin_lock_irqsave(&priv->lock, flags); 590 mcr = priv->line_control; 591 status = priv->line_status; 592 spin_unlock_irqrestore(&priv->lock, flags); 593 594 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 595 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 596 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 597 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 598 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 599 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 600 601 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 602 603 return result; 604 } 605 606 static int ch341_reset_resume(struct usb_serial *serial) 607 { 608 struct usb_serial_port *port = serial->port[0]; 609 struct ch341_private *priv = usb_get_serial_port_data(port); 610 int ret; 611 612 /* reconfigure ch341 serial port after bus-reset */ 613 ch341_configure(serial->dev, priv); 614 615 if (tty_port_initialized(&port->port)) { 616 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO); 617 if (ret) { 618 dev_err(&port->dev, "failed to submit interrupt urb: %d\n", 619 ret); 620 return ret; 621 } 622 } 623 624 return usb_serial_generic_resume(serial); 625 } 626 627 static struct usb_serial_driver ch341_device = { 628 .driver = { 629 .owner = THIS_MODULE, 630 .name = "ch341-uart", 631 }, 632 .id_table = id_table, 633 .num_ports = 1, 634 .open = ch341_open, 635 .dtr_rts = ch341_dtr_rts, 636 .carrier_raised = ch341_carrier_raised, 637 .close = ch341_close, 638 .set_termios = ch341_set_termios, 639 .break_ctl = ch341_break_ctl, 640 .tiocmget = ch341_tiocmget, 641 .tiocmset = ch341_tiocmset, 642 .tiocmiwait = usb_serial_generic_tiocmiwait, 643 .read_int_callback = ch341_read_int_callback, 644 .port_probe = ch341_port_probe, 645 .port_remove = ch341_port_remove, 646 .reset_resume = ch341_reset_resume, 647 }; 648 649 static struct usb_serial_driver * const serial_drivers[] = { 650 &ch341_device, NULL 651 }; 652 653 module_usb_serial_driver(serial_drivers, id_table); 654 655 MODULE_LICENSE("GPL"); 656