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
  97         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
  98                 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
  99
 100         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 101                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 102                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 103
 104         return r;
 105 }
 106
 107 static int ch341_control_in(struct usb_device *dev,
 108                             u8 request, u16 value, u16 index,
 109                             char *buf, unsigned bufsize)
 110 {
 111         int r;
 112
 113         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
 114                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
 115                 (int)bufsize);
 116
 117         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 118                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 119                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 120         return r;
 121 }
 122
 123 static int ch341_set_baudrate(struct usb_device *dev,
 124                               struct ch341_private *priv)
 125 {
 126         short a, b;
 127         int r;
 128         unsigned long factor;
 129         short divisor;
 130
 131         if (!priv->baud_rate)
 132                 return -EINVAL;
 133         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 134         divisor = CH341_BAUDBASE_DIVMAX;
 135
 136         while ((factor > 0xfff0) && divisor) {
 137                 factor >>= 3;
 138                 divisor--;
 139         }
 140
 141         if (factor > 0xfff0)
 142                 return -EINVAL;
 143
 144         factor = 0x10000 - factor;
 145         a = (factor & 0xff00) | divisor;
 146         b = factor & 0xff;
 147
 148         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 149         if (!r)
 150                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 151
 152         return r;
 153 }
 154
 155 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 156 {
 157         return ch341_control_out(dev, 0xa4, ~control, 0);
 158 }
 159
 160 static 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         buffer = kmalloc(size, GFP_KERNEL);
 168         if (!buffer)
 169                 return -ENOMEM;
 170
 171         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 172         if (r < 0)
 173                 goto out;
 174
 175         /* setup the private status if available */
 176         if (r == 2) {
 177                 r = 0;
 178                 spin_lock_irqsave(&priv->lock, flags);
 179                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 180                 priv->multi_status_change = 0;
 181                 spin_unlock_irqrestore(&priv->lock, flags);
 182         } else
 183                 r = -EPROTO;
 184
 185 out:    kfree(buffer);
 186         return r;
 187 }
 188
 189 /* -------------------------------------------------------------------------- */
 190
 191 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 192 {
 193         char *buffer;
 194         int r;
 195         const unsigned size = 8;
 196
 197         buffer = kmalloc(size, GFP_KERNEL);
 198         if (!buffer)
 199                 return -ENOMEM;
 200
 201         /* expect two bytes 0x27 0x00 */
 202         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 203         if (r < 0)
 204                 goto out;
 205
 206         r = ch341_control_out(dev, 0xa1, 0, 0);
 207         if (r < 0)
 208                 goto out;
 209
 210         r = ch341_set_baudrate(dev, priv);
 211         if (r < 0)
 212                 goto out;
 213
 214         /* expect two bytes 0x56 0x00 */
 215         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 216         if (r < 0)
 217                 goto out;
 218
 219         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 220         if (r < 0)
 221                 goto out;
 222
 223         /* expect 0xff 0xee */
 224         r = ch341_get_status(dev, priv);
 225         if (r < 0)
 226                 goto out;
 227
 228         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 229         if (r < 0)
 230                 goto out;
 231
 232         r = ch341_set_baudrate(dev, priv);
 233         if (r < 0)
 234                 goto out;
 235
 236         r = ch341_set_handshake(dev, priv->line_control);
 237         if (r < 0)
 238                 goto out;
 239
 240         /* expect 0x9f 0xee */
 241         r = ch341_get_status(dev, priv);
 242
 243 out:    kfree(buffer);
 244         return r;
 245 }
 246
 247 /* allocate private data */
 248 static int ch341_attach(struct usb_serial *serial)
 249 {
 250         struct ch341_private *priv;
 251         int r;
 252
 253         /* private data */
 254         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 255         if (!priv)
 256                 return -ENOMEM;
 257
 258         spin_lock_init(&priv->lock);
 259         init_waitqueue_head(&priv->delta_msr_wait);
 260         priv->baud_rate = DEFAULT_BAUD_RATE;
 261         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 262
 263         r = ch341_configure(serial->dev, priv);
 264         if (r < 0)
 265                 goto error;
 266
 267         usb_set_serial_port_data(serial->port[0], priv);
 268         return 0;
 269
 270 error:  kfree(priv);
 271         return r;
 272 }
 273
 274 static int ch341_carrier_raised(struct usb_serial_port *port)
 275 {
 276         struct ch341_private *priv = usb_get_serial_port_data(port);
 277         if (priv->line_status & CH341_BIT_DCD)
 278                 return 1;
 279         return 0;
 280 }
 281
 282 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 283 {
 284         struct ch341_private *priv = usb_get_serial_port_data(port);
 285         unsigned long flags;
 286
 287         /* drop DTR and RTS */
 288         spin_lock_irqsave(&priv->lock, flags);
 289         if (on)
 290                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 291         else
 292                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 293         spin_unlock_irqrestore(&priv->lock, flags);
 294         ch341_set_handshake(port->serial->dev, priv->line_control);
 295         wake_up_interruptible(&priv->delta_msr_wait);
 296 }
 297
 298 static void ch341_close(struct usb_serial_port *port)
 299 {
 300         usb_serial_generic_close(port);
 301         usb_kill_urb(port->interrupt_in_urb);
 302 }
 303
 304
 305 /* open this device, set default parameters */
 306 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 307 {
 308         struct usb_serial *serial = port->serial;
 309         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 310         int r;
 311
 312         priv->baud_rate = DEFAULT_BAUD_RATE;
 313
 314         r = ch341_configure(serial->dev, priv);
 315         if (r)
 316                 goto out;
 317
 318         r = ch341_set_handshake(serial->dev, priv->line_control);
 319         if (r)
 320                 goto out;
 321
 322         r = ch341_set_baudrate(serial->dev, priv);
 323         if (r)
 324                 goto out;
 325
 326         dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
 327         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 328         if (r) {
 329                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 330                         " error %d\n", __func__, r);
 331                 ch341_close(port);
 332                 goto out;
 333         }
 334
 335         r = usb_serial_generic_open(tty, port);
 336
 337 out:    return r;
 338 }
 339
 340 /* Old_termios contains the original termios settings and
 341  * tty->termios contains the new setting to be used.
 342  */
 343 static void ch341_set_termios(struct tty_struct *tty,
 344                 struct usb_serial_port *port, struct ktermios *old_termios)
 345 {
 346         struct ch341_private *priv = usb_get_serial_port_data(port);
 347         unsigned baud_rate;
 348         unsigned long flags;
 349
 350         baud_rate = tty_get_baud_rate(tty);
 351
 352         priv->baud_rate = baud_rate;
 353
 354         if (baud_rate) {
 355                 spin_lock_irqsave(&priv->lock, flags);
 356                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 357                 spin_unlock_irqrestore(&priv->lock, flags);
 358                 ch341_set_baudrate(port->serial->dev, priv);
 359         } else {
 360                 spin_lock_irqsave(&priv->lock, flags);
 361                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 362                 spin_unlock_irqrestore(&priv->lock, flags);
 363         }
 364
 365         ch341_set_handshake(port->serial->dev, priv->line_control);
 366
 367         /* Unimplemented:
 368          * (cflag & CSIZE) : data bits [5, 8]
 369          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 370          * (cflag & CSTOPB) : stop bits [1, 2]
 371          */
 372 }
 373
 374 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 375 {
 376         const uint16_t ch341_break_reg =
 377                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
 378         struct usb_serial_port *port = tty->driver_data;
 379         int r;
 380         uint16_t reg_contents;
 381         uint8_t *break_reg;
 382
 383         break_reg = kmalloc(2, GFP_KERNEL);
 384         if (!break_reg) {
 385                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 386                 return;
 387         }
 388
 389         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 390                         ch341_break_reg, 0, break_reg, 2);
 391         if (r < 0) {
 392                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 393                                 __func__, r);
 394                 goto out;
 395         }
 396         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
 397                 __func__, break_reg[0], break_reg[1]);
 398         if (break_state != 0) {
 399                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
 400                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 401                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 402         } else {
 403                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
 404                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 405                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 406         }
 407         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
 408                 __func__, break_reg[0], break_reg[1]);
 409         reg_contents = get_unaligned_le16(break_reg);
 410         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 411                         ch341_break_reg, reg_contents);
 412         if (r < 0)
 413                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 414                                 __func__, r);
 415 out:
 416         kfree(break_reg);
 417 }
 418
 419 static int ch341_tiocmset(struct tty_struct *tty,
 420                           unsigned int set, unsigned int clear)
 421 {
 422         struct usb_serial_port *port = tty->driver_data;
 423         struct ch341_private *priv = usb_get_serial_port_data(port);
 424         unsigned long flags;
 425         u8 control;
 426
 427         spin_lock_irqsave(&priv->lock, flags);
 428         if (set & TIOCM_RTS)
 429                 priv->line_control |= CH341_BIT_RTS;
 430         if (set & TIOCM_DTR)
 431                 priv->line_control |= CH341_BIT_DTR;
 432         if (clear & TIOCM_RTS)
 433                 priv->line_control &= ~CH341_BIT_RTS;
 434         if (clear & TIOCM_DTR)
 435                 priv->line_control &= ~CH341_BIT_DTR;
 436         control = priv->line_control;
 437         spin_unlock_irqrestore(&priv->lock, flags);
 438
 439         return ch341_set_handshake(port->serial->dev, control);
 440 }
 441
 442 static void ch341_read_int_callback(struct urb *urb)
 443 {
 444         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 445         unsigned char *data = urb->transfer_buffer;
 446         unsigned int actual_length = urb->actual_length;
 447         int status;
 448
 449         switch (urb->status) {
 450         case 0:
 451                 /* success */
 452                 break;
 453         case -ECONNRESET:
 454         case -ENOENT:
 455         case -ESHUTDOWN:
 456                 /* this urb is terminated, clean up */
 457                 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
 458                         __func__, urb->status);
 459                 return;
 460         default:
 461                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
 462                         __func__, urb->status);
 463                 goto exit;
 464         }
 465
 466         usb_serial_debug_data(&port->dev, __func__,
 467                               urb->actual_length, urb->transfer_buffer);
 468
 469         if (actual_length >= 4) {
 470                 struct ch341_private *priv = usb_get_serial_port_data(port);
 471                 unsigned long flags;
 472                 u8 prev_line_status = priv->line_status;
 473
 474                 spin_lock_irqsave(&priv->lock, flags);
 475                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 476                 if ((data[1] & CH341_MULT_STAT))
 477                         priv->multi_status_change = 1;
 478                 spin_unlock_irqrestore(&priv->lock, flags);
 479
 480                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 481                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 482                         if (tty)
 483                                 usb_serial_handle_dcd_change(port, tty,
 484                                             priv->line_status & CH341_BIT_DCD);
 485                         tty_kref_put(tty);
 486                 }
 487
 488                 wake_up_interruptible(&priv->delta_msr_wait);
 489         }
 490
 491 exit:
 492         status = usb_submit_urb(urb, GFP_ATOMIC);
 493         if (status)
 494                 dev_err(&urb->dev->dev,
 495                         "%s - usb_submit_urb failed with result %d\n",
 496                         __func__, status);
 497 }
 498
 499 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 500 {
 501         struct ch341_private *priv = usb_get_serial_port_data(port);
 502         unsigned long flags;
 503         u8 prevstatus;
 504         u8 status;
 505         u8 changed;
 506         u8 multi_change = 0;
 507
 508         spin_lock_irqsave(&priv->lock, flags);
 509         prevstatus = priv->line_status;
 510         priv->multi_status_change = 0;
 511         spin_unlock_irqrestore(&priv->lock, flags);
 512
 513         while (!multi_change) {
 514                 interruptible_sleep_on(&priv->delta_msr_wait);
 515                 /* see if a signal did it */
 516                 if (signal_pending(current))
 517                         return -ERESTARTSYS;
 518
 519                 spin_lock_irqsave(&priv->lock, flags);
 520                 status = priv->line_status;
 521                 multi_change = priv->multi_status_change;
 522                 spin_unlock_irqrestore(&priv->lock, flags);
 523
 524                 changed = prevstatus ^ status;
 525
 526                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 527                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 528                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 529                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 530                         return 0;
 531                 }
 532                 prevstatus = status;
 533         }
 534
 535         return 0;
 536 }
 537
 538 static int ch341_ioctl(struct tty_struct *tty,
 539                         unsigned int cmd, unsigned long arg)
 540 {
 541         struct usb_serial_port *port = tty->driver_data;
 542
 543         dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd);
 544
 545         switch (cmd) {
 546         case TIOCMIWAIT:
 547                 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__,  port->number);
 548                 return wait_modem_info(port, arg);
 549
 550         default:
 551                 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd);
 552                 break;
 553         }
 554
 555         return -ENOIOCTLCMD;
 556 }
 557
 558 static int ch341_tiocmget(struct tty_struct *tty)
 559 {
 560         struct usb_serial_port *port = tty->driver_data;
 561         struct ch341_private *priv = usb_get_serial_port_data(port);
 562         unsigned long flags;
 563         u8 mcr;
 564         u8 status;
 565         unsigned int result;
 566
 567         spin_lock_irqsave(&priv->lock, flags);
 568         mcr = priv->line_control;
 569         status = priv->line_status;
 570         spin_unlock_irqrestore(&priv->lock, flags);
 571
 572         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 573                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 574                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 575                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 576                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 577                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 578
 579         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 580
 581         return result;
 582 }
 583
 584 static int ch341_reset_resume(struct usb_serial *serial)
 585 {
 586         struct ch341_private *priv;
 587
 588         priv = usb_get_serial_port_data(serial->port[0]);
 589
 590         /* reconfigure ch341 serial port after bus-reset */
 591         ch341_configure(serial->dev, priv);
 592
 593         return 0;
 594 }
 595
 596 static struct usb_serial_driver ch341_device = {
 597         .driver = {
 598                 .owner  = THIS_MODULE,
 599                 .name   = "ch341-uart",
 600         },
 601         .id_table          = id_table,
 602         .num_ports         = 1,
 603         .open              = ch341_open,
 604         .dtr_rts           = ch341_dtr_rts,
 605         .carrier_raised    = ch341_carrier_raised,
 606         .close             = ch341_close,
 607         .ioctl             = ch341_ioctl,
 608         .set_termios       = ch341_set_termios,
 609         .break_ctl         = ch341_break_ctl,
 610         .tiocmget          = ch341_tiocmget,
 611         .tiocmset          = ch341_tiocmset,
 612         .read_int_callback = ch341_read_int_callback,
 613         .attach            = ch341_attach,
 614         .reset_resume      = ch341_reset_resume,
 615 };
 616
 617 static struct usb_serial_driver * const serial_drivers[] = {
 618         &ch341_device, NULL
 619 };
 620
 621 module_usb_serial_driver(serial_drivers, id_table);
 622
 623 MODULE_LICENSE("GPL");
 624
 625 module_param(debug, bool, S_IRUGO | S_IWUSR);
 626 MODULE_PARM_DESC(debug, "Debug enabled or not");