drivers/usb/serial/ch341.c

   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");