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 73static bool debug; 74 75static const struct usb_device_id id_table[] = { 76 { USB_DEVICE(0x4348, 0x5523) }, 77 { USB_DEVICE(0x1a86, 0x7523) }, 78 { USB_DEVICE(0x1a86, 0x5523) }, 79 { }, 80}; 81MODULE_DEVICE_TABLE(usb, id_table); 82 83struct 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 92static 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 106static 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 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 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 154static 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 160static 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 187out: kfree(buffer); 188 return r; 189} 190 191/* -------------------------------------------------------------------------- */ 192 193static 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 247out: kfree(buffer); 248 return r; 249} 250 251/* allocate private data */ 252static 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 276error: kfree(priv); 277 return r; 278} 279 280static 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 288static 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 305static 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 */ 315static 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 348out: return r; 349} 350 351/* Old_termios contains the original termios settings and 352 * tty->termios contains the new setting to be used. 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; 360 361 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 387static 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); 430out: 431 kfree(break_reg); 432} 433 434static 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 457static 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 508exit: 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 516static 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 555static 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 574static 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 603static 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 620static 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 631static 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 651static struct usb_serial_driver * const serial_drivers[] = { 652 &ch341_device, NULL 653}; 654 655module_usb_serial_driver(ch341_driver, serial_drivers); 656 657MODULE_LICENSE("GPL"); 658 659module_param(debug, bool, S_IRUGO | S_IWUSR); 660MODULE_PARM_DESC(debug, "Debug enabled or not"); 661