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 73 static const struct usb_device_id id_table[] = { 74 { USB_DEVICE(0x4348, 0x5523) }, 75 { USB_DEVICE(0x1a86, 0x7523) }, 76 { USB_DEVICE(0x1a86, 0x5523) }, 77 { }, 78 }; 79 MODULE_DEVICE_TABLE(usb, id_table); 80 81 struct ch341_private { 82 spinlock_t lock; /* access lock */ 83 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ 84 unsigned baud_rate; /* set baud rate */ 85 u8 line_control; /* set line control value RTS/DTR */ 86 u8 line_status; /* active status of modem control inputs */ 87 u8 multi_status_change; /* status changed multiple since last call */ 88 }; 89 90 static int ch341_control_out(struct usb_device *dev, u8 request, 91 u16 value, u16 index) 92 { 93 int r; 94 95 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n", 96 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); 97 98 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 99 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 100 value, index, NULL, 0, DEFAULT_TIMEOUT); 101 102 return r; 103 } 104 105 static int ch341_control_in(struct usb_device *dev, 106 u8 request, u16 value, u16 index, 107 char *buf, unsigned bufsize) 108 { 109 int r; 110 111 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n", 112 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, 113 (int)bufsize); 114 115 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 116 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 117 value, index, buf, bufsize, DEFAULT_TIMEOUT); 118 return r; 119 } 120 121 static int ch341_set_baudrate(struct usb_device *dev, 122 struct ch341_private *priv) 123 { 124 short a, b; 125 int r; 126 unsigned long factor; 127 short divisor; 128 129 if (!priv->baud_rate) 130 return -EINVAL; 131 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 132 divisor = CH341_BAUDBASE_DIVMAX; 133 134 while ((factor > 0xfff0) && divisor) { 135 factor >>= 3; 136 divisor--; 137 } 138 139 if (factor > 0xfff0) 140 return -EINVAL; 141 142 factor = 0x10000 - factor; 143 a = (factor & 0xff00) | divisor; 144 b = factor & 0xff; 145 146 r = ch341_control_out(dev, 0x9a, 0x1312, a); 147 if (!r) 148 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 149 150 return r; 151 } 152 153 static int ch341_set_handshake(struct usb_device *dev, u8 control) 154 { 155 return ch341_control_out(dev, 0xa4, ~control, 0); 156 } 157 158 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 159 { 160 char *buffer; 161 int r; 162 const unsigned size = 8; 163 unsigned long flags; 164 165 buffer = kmalloc(size, GFP_KERNEL); 166 if (!buffer) 167 return -ENOMEM; 168 169 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 170 if (r < 0) 171 goto out; 172 173 /* setup the private status if available */ 174 if (r == 2) { 175 r = 0; 176 spin_lock_irqsave(&priv->lock, flags); 177 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 178 priv->multi_status_change = 0; 179 spin_unlock_irqrestore(&priv->lock, flags); 180 } else 181 r = -EPROTO; 182 183 out: kfree(buffer); 184 return r; 185 } 186 187 /* -------------------------------------------------------------------------- */ 188 189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 190 { 191 char *buffer; 192 int r; 193 const unsigned size = 8; 194 195 buffer = kmalloc(size, GFP_KERNEL); 196 if (!buffer) 197 return -ENOMEM; 198 199 /* expect two bytes 0x27 0x00 */ 200 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 201 if (r < 0) 202 goto out; 203 204 r = ch341_control_out(dev, 0xa1, 0, 0); 205 if (r < 0) 206 goto out; 207 208 r = ch341_set_baudrate(dev, priv); 209 if (r < 0) 210 goto out; 211 212 /* expect two bytes 0x56 0x00 */ 213 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 214 if (r < 0) 215 goto out; 216 217 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 218 if (r < 0) 219 goto out; 220 221 /* expect 0xff 0xee */ 222 r = ch341_get_status(dev, priv); 223 if (r < 0) 224 goto out; 225 226 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 227 if (r < 0) 228 goto out; 229 230 r = ch341_set_baudrate(dev, priv); 231 if (r < 0) 232 goto out; 233 234 r = ch341_set_handshake(dev, priv->line_control); 235 if (r < 0) 236 goto out; 237 238 /* expect 0x9f 0xee */ 239 r = ch341_get_status(dev, priv); 240 241 out: kfree(buffer); 242 return r; 243 } 244 245 static int ch341_port_probe(struct usb_serial_port *port) 246 { 247 struct ch341_private *priv; 248 int r; 249 250 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 251 if (!priv) 252 return -ENOMEM; 253 254 spin_lock_init(&priv->lock); 255 init_waitqueue_head(&priv->delta_msr_wait); 256 priv->baud_rate = DEFAULT_BAUD_RATE; 257 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 258 259 r = ch341_configure(port->serial->dev, priv); 260 if (r < 0) 261 goto error; 262 263 usb_set_serial_port_data(port, priv); 264 return 0; 265 266 error: kfree(priv); 267 return r; 268 } 269 270 static int ch341_port_remove(struct usb_serial_port *port) 271 { 272 struct ch341_private *priv; 273 274 priv = usb_get_serial_port_data(port); 275 kfree(priv); 276 277 return 0; 278 } 279 280 static 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 } 287 288 static 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 /* drop DTR and RTS */ 294 spin_lock_irqsave(&priv->lock, flags); 295 if (on) 296 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 297 else 298 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 299 spin_unlock_irqrestore(&priv->lock, flags); 300 ch341_set_handshake(port->serial->dev, priv->line_control); 301 wake_up_interruptible(&priv->delta_msr_wait); 302 } 303 304 static void ch341_close(struct usb_serial_port *port) 305 { 306 usb_serial_generic_close(port); 307 usb_kill_urb(port->interrupt_in_urb); 308 } 309 310 311 /* open this device, set default parameters */ 312 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 313 { 314 struct usb_serial *serial = port->serial; 315 struct ch341_private *priv = usb_get_serial_port_data(port); 316 int r; 317 318 priv->baud_rate = DEFAULT_BAUD_RATE; 319 320 r = ch341_configure(serial->dev, priv); 321 if (r) 322 goto out; 323 324 r = ch341_set_handshake(serial->dev, priv->line_control); 325 if (r) 326 goto out; 327 328 r = ch341_set_baudrate(serial->dev, priv); 329 if (r) 330 goto out; 331 332 dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__); 333 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 334 if (r) { 335 dev_err(&port->dev, "%s - failed submitting interrupt urb," 336 " error %d\n", __func__, r); 337 ch341_close(port); 338 goto out; 339 } 340 341 r = usb_serial_generic_open(tty, port); 342 343 out: return r; 344 } 345 346 /* Old_termios contains the original termios settings and 347 * tty->termios contains the new setting to be used. 348 */ 349 static void ch341_set_termios(struct tty_struct *tty, 350 struct usb_serial_port *port, struct ktermios *old_termios) 351 { 352 struct ch341_private *priv = usb_get_serial_port_data(port); 353 unsigned baud_rate; 354 unsigned long flags; 355 356 baud_rate = tty_get_baud_rate(tty); 357 358 priv->baud_rate = baud_rate; 359 360 if (baud_rate) { 361 spin_lock_irqsave(&priv->lock, flags); 362 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 363 spin_unlock_irqrestore(&priv->lock, flags); 364 ch341_set_baudrate(port->serial->dev, priv); 365 } else { 366 spin_lock_irqsave(&priv->lock, flags); 367 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 368 spin_unlock_irqrestore(&priv->lock, flags); 369 } 370 371 ch341_set_handshake(port->serial->dev, priv->line_control); 372 373 /* Unimplemented: 374 * (cflag & CSIZE) : data bits [5, 8] 375 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 376 * (cflag & CSTOPB) : stop bits [1, 2] 377 */ 378 } 379 380 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 381 { 382 const uint16_t ch341_break_reg = 383 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 384 struct usb_serial_port *port = tty->driver_data; 385 int r; 386 uint16_t reg_contents; 387 uint8_t *break_reg; 388 389 break_reg = kmalloc(2, GFP_KERNEL); 390 if (!break_reg) { 391 dev_err(&port->dev, "%s - kmalloc failed\n", __func__); 392 return; 393 } 394 395 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 396 ch341_break_reg, 0, break_reg, 2); 397 if (r < 0) { 398 dev_err(&port->dev, "%s - USB control read error (%d)\n", 399 __func__, r); 400 goto out; 401 } 402 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 403 __func__, break_reg[0], break_reg[1]); 404 if (break_state != 0) { 405 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 406 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 407 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 408 } else { 409 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 410 break_reg[0] |= CH341_NBREAK_BITS_REG1; 411 break_reg[1] |= CH341_NBREAK_BITS_REG2; 412 } 413 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 414 __func__, break_reg[0], break_reg[1]); 415 reg_contents = get_unaligned_le16(break_reg); 416 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 417 ch341_break_reg, reg_contents); 418 if (r < 0) 419 dev_err(&port->dev, "%s - USB control write error (%d)\n", 420 __func__, r); 421 out: 422 kfree(break_reg); 423 } 424 425 static int ch341_tiocmset(struct tty_struct *tty, 426 unsigned int set, unsigned int clear) 427 { 428 struct usb_serial_port *port = tty->driver_data; 429 struct ch341_private *priv = usb_get_serial_port_data(port); 430 unsigned long flags; 431 u8 control; 432 433 spin_lock_irqsave(&priv->lock, flags); 434 if (set & TIOCM_RTS) 435 priv->line_control |= CH341_BIT_RTS; 436 if (set & TIOCM_DTR) 437 priv->line_control |= CH341_BIT_DTR; 438 if (clear & TIOCM_RTS) 439 priv->line_control &= ~CH341_BIT_RTS; 440 if (clear & TIOCM_DTR) 441 priv->line_control &= ~CH341_BIT_DTR; 442 control = priv->line_control; 443 spin_unlock_irqrestore(&priv->lock, flags); 444 445 return ch341_set_handshake(port->serial->dev, control); 446 } 447 448 static void ch341_read_int_callback(struct urb *urb) 449 { 450 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 451 unsigned char *data = urb->transfer_buffer; 452 unsigned int actual_length = urb->actual_length; 453 int status; 454 455 switch (urb->status) { 456 case 0: 457 /* success */ 458 break; 459 case -ECONNRESET: 460 case -ENOENT: 461 case -ESHUTDOWN: 462 /* this urb is terminated, clean up */ 463 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n", 464 __func__, urb->status); 465 return; 466 default: 467 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n", 468 __func__, urb->status); 469 goto exit; 470 } 471 472 usb_serial_debug_data(&port->dev, __func__, 473 urb->actual_length, urb->transfer_buffer); 474 475 if (actual_length >= 4) { 476 struct ch341_private *priv = usb_get_serial_port_data(port); 477 unsigned long flags; 478 u8 prev_line_status = priv->line_status; 479 480 spin_lock_irqsave(&priv->lock, flags); 481 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 482 if ((data[1] & CH341_MULT_STAT)) 483 priv->multi_status_change = 1; 484 spin_unlock_irqrestore(&priv->lock, flags); 485 486 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) { 487 struct tty_struct *tty = tty_port_tty_get(&port->port); 488 if (tty) 489 usb_serial_handle_dcd_change(port, tty, 490 priv->line_status & CH341_BIT_DCD); 491 tty_kref_put(tty); 492 } 493 494 wake_up_interruptible(&priv->delta_msr_wait); 495 } 496 497 exit: 498 status = usb_submit_urb(urb, GFP_ATOMIC); 499 if (status) 500 dev_err(&urb->dev->dev, 501 "%s - usb_submit_urb failed with result %d\n", 502 __func__, status); 503 } 504 505 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 506 { 507 struct ch341_private *priv = usb_get_serial_port_data(port); 508 unsigned long flags; 509 u8 prevstatus; 510 u8 status; 511 u8 changed; 512 u8 multi_change = 0; 513 514 spin_lock_irqsave(&priv->lock, flags); 515 prevstatus = priv->line_status; 516 priv->multi_status_change = 0; 517 spin_unlock_irqrestore(&priv->lock, flags); 518 519 while (!multi_change) { 520 interruptible_sleep_on(&priv->delta_msr_wait); 521 /* see if a signal did it */ 522 if (signal_pending(current)) 523 return -ERESTARTSYS; 524 525 spin_lock_irqsave(&priv->lock, flags); 526 status = priv->line_status; 527 multi_change = priv->multi_status_change; 528 spin_unlock_irqrestore(&priv->lock, flags); 529 530 changed = prevstatus ^ status; 531 532 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 533 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 534 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 535 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 536 return 0; 537 } 538 prevstatus = status; 539 } 540 541 return 0; 542 } 543 544 static int ch341_ioctl(struct tty_struct *tty, 545 unsigned int cmd, unsigned long arg) 546 { 547 struct usb_serial_port *port = tty->driver_data; 548 549 dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd); 550 551 switch (cmd) { 552 case TIOCMIWAIT: 553 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__, port->number); 554 return wait_modem_info(port, arg); 555 556 default: 557 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd); 558 break; 559 } 560 561 return -ENOIOCTLCMD; 562 } 563 564 static int ch341_tiocmget(struct tty_struct *tty) 565 { 566 struct usb_serial_port *port = tty->driver_data; 567 struct ch341_private *priv = usb_get_serial_port_data(port); 568 unsigned long flags; 569 u8 mcr; 570 u8 status; 571 unsigned int result; 572 573 spin_lock_irqsave(&priv->lock, flags); 574 mcr = priv->line_control; 575 status = priv->line_status; 576 spin_unlock_irqrestore(&priv->lock, flags); 577 578 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 579 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 580 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 581 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 582 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 583 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 584 585 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 586 587 return result; 588 } 589 590 static int ch341_reset_resume(struct usb_serial *serial) 591 { 592 struct ch341_private *priv; 593 594 priv = usb_get_serial_port_data(serial->port[0]); 595 596 /* reconfigure ch341 serial port after bus-reset */ 597 ch341_configure(serial->dev, priv); 598 599 return 0; 600 } 601 602 static struct usb_serial_driver ch341_device = { 603 .driver = { 604 .owner = THIS_MODULE, 605 .name = "ch341-uart", 606 }, 607 .id_table = id_table, 608 .num_ports = 1, 609 .open = ch341_open, 610 .dtr_rts = ch341_dtr_rts, 611 .carrier_raised = ch341_carrier_raised, 612 .close = ch341_close, 613 .ioctl = ch341_ioctl, 614 .set_termios = ch341_set_termios, 615 .break_ctl = ch341_break_ctl, 616 .tiocmget = ch341_tiocmget, 617 .tiocmset = ch341_tiocmset, 618 .read_int_callback = ch341_read_int_callback, 619 .port_probe = ch341_port_probe, 620 .port_remove = ch341_port_remove, 621 .reset_resume = ch341_reset_resume, 622 }; 623 624 static struct usb_serial_driver * const serial_drivers[] = { 625 &ch341_device, NULL 626 }; 627 628 module_usb_serial_driver(serial_drivers, id_table); 629 630 MODULE_LICENSE("GPL"); 631