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 bool debug; 74 75 static const struct usb_device_id id_table[] = { 76 { USB_DEVICE(0x4348, 0x5523) }, 77 { USB_DEVICE(0x1a86, 0x7523) }, 78 { USB_DEVICE(0x1a86, 0x5523) }, 79 { }, 80 }; 81 MODULE_DEVICE_TABLE(usb, id_table); 82 83 struct 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 92 static 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 } 105 106 static 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 } 119 120 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 /* allocate private data */ 245 static int ch341_attach(struct usb_serial *serial) 246 { 247 struct ch341_private *priv; 248 int r; 249 250 /* private data */ 251 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 252 if (!priv) 253 return -ENOMEM; 254 255 spin_lock_init(&priv->lock); 256 init_waitqueue_head(&priv->delta_msr_wait); 257 priv->baud_rate = DEFAULT_BAUD_RATE; 258 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 259 260 r = ch341_configure(serial->dev, priv); 261 if (r < 0) 262 goto error; 263 264 usb_set_serial_port_data(serial->port[0], priv); 265 return 0; 266 267 error: kfree(priv); 268 return r; 269 } 270 271 static int ch341_carrier_raised(struct usb_serial_port *port) 272 { 273 struct ch341_private *priv = usb_get_serial_port_data(port); 274 if (priv->line_status & CH341_BIT_DCD) 275 return 1; 276 return 0; 277 } 278 279 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 280 { 281 struct ch341_private *priv = usb_get_serial_port_data(port); 282 unsigned long flags; 283 284 /* drop DTR and RTS */ 285 spin_lock_irqsave(&priv->lock, flags); 286 if (on) 287 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 288 else 289 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 290 spin_unlock_irqrestore(&priv->lock, flags); 291 ch341_set_handshake(port->serial->dev, priv->line_control); 292 wake_up_interruptible(&priv->delta_msr_wait); 293 } 294 295 static void ch341_close(struct usb_serial_port *port) 296 { 297 usb_serial_generic_close(port); 298 usb_kill_urb(port->interrupt_in_urb); 299 } 300 301 302 /* open this device, set default parameters */ 303 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 304 { 305 struct usb_serial *serial = port->serial; 306 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); 307 int r; 308 309 priv->baud_rate = DEFAULT_BAUD_RATE; 310 311 r = ch341_configure(serial->dev, priv); 312 if (r) 313 goto out; 314 315 r = ch341_set_handshake(serial->dev, priv->line_control); 316 if (r) 317 goto out; 318 319 r = ch341_set_baudrate(serial->dev, priv); 320 if (r) 321 goto out; 322 323 dbg("%s - submitting interrupt urb", __func__); 324 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 325 if (r) { 326 dev_err(&port->dev, "%s - failed submitting interrupt urb," 327 " error %d\n", __func__, r); 328 ch341_close(port); 329 goto out; 330 } 331 332 r = usb_serial_generic_open(tty, port); 333 334 out: return r; 335 } 336 337 /* Old_termios contains the original termios settings and 338 * tty->termios contains the new setting to be used. 339 */ 340 static void ch341_set_termios(struct tty_struct *tty, 341 struct usb_serial_port *port, struct ktermios *old_termios) 342 { 343 struct ch341_private *priv = usb_get_serial_port_data(port); 344 unsigned baud_rate; 345 unsigned long flags; 346 347 baud_rate = tty_get_baud_rate(tty); 348 349 priv->baud_rate = baud_rate; 350 351 if (baud_rate) { 352 spin_lock_irqsave(&priv->lock, flags); 353 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 354 spin_unlock_irqrestore(&priv->lock, flags); 355 ch341_set_baudrate(port->serial->dev, priv); 356 } else { 357 spin_lock_irqsave(&priv->lock, flags); 358 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 359 spin_unlock_irqrestore(&priv->lock, flags); 360 } 361 362 ch341_set_handshake(port->serial->dev, priv->line_control); 363 364 /* Unimplemented: 365 * (cflag & CSIZE) : data bits [5, 8] 366 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 367 * (cflag & CSTOPB) : stop bits [1, 2] 368 */ 369 } 370 371 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 372 { 373 const uint16_t ch341_break_reg = 374 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 375 struct usb_serial_port *port = tty->driver_data; 376 int r; 377 uint16_t reg_contents; 378 uint8_t *break_reg; 379 380 break_reg = kmalloc(2, GFP_KERNEL); 381 if (!break_reg) { 382 dev_err(&port->dev, "%s - kmalloc failed\n", __func__); 383 return; 384 } 385 386 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 387 ch341_break_reg, 0, break_reg, 2); 388 if (r < 0) { 389 dev_err(&port->dev, "%s - USB control read error (%d)\n", 390 __func__, r); 391 goto out; 392 } 393 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x", 394 __func__, break_reg[0], break_reg[1]); 395 if (break_state != 0) { 396 dbg("%s - Enter break state requested", __func__); 397 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 398 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 399 } else { 400 dbg("%s - Leave break state requested", __func__); 401 break_reg[0] |= CH341_NBREAK_BITS_REG1; 402 break_reg[1] |= CH341_NBREAK_BITS_REG2; 403 } 404 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x", 405 __func__, break_reg[0], break_reg[1]); 406 reg_contents = get_unaligned_le16(break_reg); 407 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 408 ch341_break_reg, reg_contents); 409 if (r < 0) 410 dev_err(&port->dev, "%s - USB control write error (%d)\n", 411 __func__, r); 412 out: 413 kfree(break_reg); 414 } 415 416 static int ch341_tiocmset(struct tty_struct *tty, 417 unsigned int set, unsigned int clear) 418 { 419 struct usb_serial_port *port = tty->driver_data; 420 struct ch341_private *priv = usb_get_serial_port_data(port); 421 unsigned long flags; 422 u8 control; 423 424 spin_lock_irqsave(&priv->lock, flags); 425 if (set & TIOCM_RTS) 426 priv->line_control |= CH341_BIT_RTS; 427 if (set & TIOCM_DTR) 428 priv->line_control |= CH341_BIT_DTR; 429 if (clear & TIOCM_RTS) 430 priv->line_control &= ~CH341_BIT_RTS; 431 if (clear & TIOCM_DTR) 432 priv->line_control &= ~CH341_BIT_DTR; 433 control = priv->line_control; 434 spin_unlock_irqrestore(&priv->lock, flags); 435 436 return ch341_set_handshake(port->serial->dev, control); 437 } 438 439 static void ch341_read_int_callback(struct urb *urb) 440 { 441 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 442 unsigned char *data = urb->transfer_buffer; 443 unsigned int actual_length = urb->actual_length; 444 int status; 445 446 switch (urb->status) { 447 case 0: 448 /* success */ 449 break; 450 case -ECONNRESET: 451 case -ENOENT: 452 case -ESHUTDOWN: 453 /* this urb is terminated, clean up */ 454 dbg("%s - urb shutting down with status: %d", __func__, 455 urb->status); 456 return; 457 default: 458 dbg("%s - nonzero urb status received: %d", __func__, 459 urb->status); 460 goto exit; 461 } 462 463 usb_serial_debug_data(debug, &port->dev, __func__, 464 urb->actual_length, urb->transfer_buffer); 465 466 if (actual_length >= 4) { 467 struct ch341_private *priv = usb_get_serial_port_data(port); 468 unsigned long flags; 469 u8 prev_line_status = priv->line_status; 470 471 spin_lock_irqsave(&priv->lock, flags); 472 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 473 if ((data[1] & CH341_MULT_STAT)) 474 priv->multi_status_change = 1; 475 spin_unlock_irqrestore(&priv->lock, flags); 476 477 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) { 478 struct tty_struct *tty = tty_port_tty_get(&port->port); 479 if (tty) 480 usb_serial_handle_dcd_change(port, tty, 481 priv->line_status & CH341_BIT_DCD); 482 tty_kref_put(tty); 483 } 484 485 wake_up_interruptible(&priv->delta_msr_wait); 486 } 487 488 exit: 489 status = usb_submit_urb(urb, GFP_ATOMIC); 490 if (status) 491 dev_err(&urb->dev->dev, 492 "%s - usb_submit_urb failed with result %d\n", 493 __func__, status); 494 } 495 496 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 497 { 498 struct ch341_private *priv = usb_get_serial_port_data(port); 499 unsigned long flags; 500 u8 prevstatus; 501 u8 status; 502 u8 changed; 503 u8 multi_change = 0; 504 505 spin_lock_irqsave(&priv->lock, flags); 506 prevstatus = priv->line_status; 507 priv->multi_status_change = 0; 508 spin_unlock_irqrestore(&priv->lock, flags); 509 510 while (!multi_change) { 511 interruptible_sleep_on(&priv->delta_msr_wait); 512 /* see if a signal did it */ 513 if (signal_pending(current)) 514 return -ERESTARTSYS; 515 516 spin_lock_irqsave(&priv->lock, flags); 517 status = priv->line_status; 518 multi_change = priv->multi_status_change; 519 spin_unlock_irqrestore(&priv->lock, flags); 520 521 changed = prevstatus ^ status; 522 523 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 524 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 525 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 526 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 527 return 0; 528 } 529 prevstatus = status; 530 } 531 532 return 0; 533 } 534 535 static int ch341_ioctl(struct tty_struct *tty, 536 unsigned int cmd, unsigned long arg) 537 { 538 struct usb_serial_port *port = tty->driver_data; 539 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); 540 541 switch (cmd) { 542 case TIOCMIWAIT: 543 dbg("%s (%d) TIOCMIWAIT", __func__, port->number); 544 return wait_modem_info(port, arg); 545 546 default: 547 dbg("%s not supported = 0x%04x", __func__, cmd); 548 break; 549 } 550 551 return -ENOIOCTLCMD; 552 } 553 554 static int ch341_tiocmget(struct tty_struct *tty) 555 { 556 struct usb_serial_port *port = tty->driver_data; 557 struct ch341_private *priv = usb_get_serial_port_data(port); 558 unsigned long flags; 559 u8 mcr; 560 u8 status; 561 unsigned int result; 562 563 spin_lock_irqsave(&priv->lock, flags); 564 mcr = priv->line_control; 565 status = priv->line_status; 566 spin_unlock_irqrestore(&priv->lock, flags); 567 568 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 569 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 570 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 571 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 572 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 573 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 574 575 dbg("%s - result = %x", __func__, result); 576 577 return result; 578 } 579 580 static int ch341_reset_resume(struct usb_serial *serial) 581 { 582 struct ch341_private *priv; 583 584 priv = usb_get_serial_port_data(serial->port[0]); 585 586 /* reconfigure ch341 serial port after bus-reset */ 587 ch341_configure(serial->dev, priv); 588 589 return 0; 590 } 591 592 static struct usb_serial_driver ch341_device = { 593 .driver = { 594 .owner = THIS_MODULE, 595 .name = "ch341-uart", 596 }, 597 .id_table = id_table, 598 .num_ports = 1, 599 .open = ch341_open, 600 .dtr_rts = ch341_dtr_rts, 601 .carrier_raised = ch341_carrier_raised, 602 .close = ch341_close, 603 .ioctl = ch341_ioctl, 604 .set_termios = ch341_set_termios, 605 .break_ctl = ch341_break_ctl, 606 .tiocmget = ch341_tiocmget, 607 .tiocmset = ch341_tiocmset, 608 .read_int_callback = ch341_read_int_callback, 609 .attach = ch341_attach, 610 .reset_resume = ch341_reset_resume, 611 }; 612 613 static struct usb_serial_driver * const serial_drivers[] = { 614 &ch341_device, NULL 615 }; 616 617 module_usb_serial_driver(serial_drivers, id_table); 618 619 MODULE_LICENSE("GPL"); 620 621 module_param(debug, bool, S_IRUGO | S_IWUSR); 622 MODULE_PARM_DESC(debug, "Debug enabled or not"); 623