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 unsigned baud_rate; /* set baud rate */ 84 u8 line_control; /* set line control value RTS/DTR */ 85 u8 line_status; /* active status of modem control inputs */ 86 u8 multi_status_change; /* status changed multiple since last call */ 87 }; 88 89 static 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 } 103 104 static 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 } 119 120 static 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 } 151 152 static int ch341_set_handshake(struct usb_device *dev, u8 control) 153 { 154 return ch341_control_out(dev, 0xa4, ~control, 0); 155 } 156 157 static 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 /* setup the private status if available */ 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; 181 182 out: kfree(buffer); 183 return r; 184 } 185 186 /* -------------------------------------------------------------------------- */ 187 188 static 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 /* expect two bytes 0x27 0x00 */ 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 /* expect two bytes 0x56 0x00 */ 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 /* expect 0xff 0xee */ 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 /* expect 0x9f 0xee */ 238 r = ch341_get_status(dev, priv); 239 240 out: kfree(buffer); 241 return r; 242 } 243 244 static 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; 263 264 error: kfree(priv); 265 return r; 266 } 267 268 static 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 } 277 278 static 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 } 285 286 static 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 /* drop DTR and RTS */ 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 } 300 301 static 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 /* open this device, set default parameters */ 309 static 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); 339 340 out: return r; 341 } 342 343 /* Old_termios contains the original termios settings and 344 * tty->termios contains the new setting to be used. 345 */ 346 static 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 /* Unimplemented: 371 * (cflag & CSIZE) : data bits [5, 8] 372 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 373 * (cflag & CSTOPB) : stop bits [1, 2] 374 */ 375 } 376 377 static 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); 418 out: 419 kfree(break_reg); 420 } 421 422 static 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 } 444 445 static 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 /* success */ 455 break; 456 case -ECONNRESET: 457 case -ENOENT: 458 case -ESHUTDOWN: 459 /* this urb is terminated, clean up */ 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 } 493 494 exit: 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 } 501 502 static 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 /* see if a signal did it */ 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 } 544 545 static 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 } 570 571 static 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 /* reconfigure ch341 serial port after bus-reset */ 578 ch341_configure(serial->dev, priv); 579 580 return 0; 581 } 582 583 static 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 }; 604 605 static struct usb_serial_driver * const serial_drivers[] = { 606 &ch341_device, NULL 607 }; 608 609 module_usb_serial_driver(serial_drivers, id_table); 610 611 MODULE_LICENSE("GPL"); 612