drivers/tty/serial/jsm/jsm_tty.c

   1 /************************************************************************
   2  * Copyright 2003 Digi International (www.digi.com)
   3  *
   4  * Copyright (C) 2004 IBM Corporation. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
  13  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  14  * PURPOSE.  See the GNU General Public License for more details.
  15  *
  16  * Contact Information:
  17  * Scott H Kilau <Scott_Kilau@digi.com>
  18  * Ananda Venkatarman <mansarov@us.ibm.com>
  19  * Modifications:
  20  * 01/19/06:    changed jsm_input routine to use the dynamically allocated
  21  *              tty_buffer changes. Contributors: Scott Kilau and Ananda V.
  22  ***********************************************************************/
  23 #include <linux/tty.h>
  24 #include <linux/tty_flip.h>
  25 #include <linux/serial_reg.h>
  26 #include <linux/delay.h>        /* For udelay */
  27 #include <linux/pci.h>
  28 #include <linux/slab.h>
  29
  30 #include "jsm.h"
  31
  32 static DECLARE_BITMAP(linemap, MAXLINES);
  33
  34 static void jsm_carrier(struct jsm_channel *ch);
  35
  36 static inline int jsm_get_mstat(struct jsm_channel *ch)
  37 {
  38         unsigned char mstat;
  39         unsigned result;
  40
  41         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "start\n");
  42
  43         mstat = (ch->ch_mostat | ch->ch_mistat);
  44
  45         result = 0;
  46
  47         if (mstat & UART_MCR_DTR)
  48                 result |= TIOCM_DTR;
  49         if (mstat & UART_MCR_RTS)
  50                 result |= TIOCM_RTS;
  51         if (mstat & UART_MSR_CTS)
  52                 result |= TIOCM_CTS;
  53         if (mstat & UART_MSR_DSR)
  54                 result |= TIOCM_DSR;
  55         if (mstat & UART_MSR_RI)
  56                 result |= TIOCM_RI;
  57         if (mstat & UART_MSR_DCD)
  58                 result |= TIOCM_CD;
  59
  60         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
  61         return result;
  62 }
  63
  64 static unsigned int jsm_tty_tx_empty(struct uart_port *port)
  65 {
  66         return TIOCSER_TEMT;
  67 }
  68
  69 /*
  70  * Return modem signals to ld.
  71  */
  72 static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
  73 {
  74         int result;
  75         struct jsm_channel *channel =
  76                 container_of(port, struct jsm_channel, uart_port);
  77
  78         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
  79
  80         result = jsm_get_mstat(channel);
  81
  82         if (result < 0)
  83                 return -ENXIO;
  84
  85         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
  86
  87         return result;
  88 }
  89
  90 /*
  91  * jsm_set_modem_info()
  92  *
  93  * Set modem signals, called by ld.
  94  */
  95 static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)
  96 {
  97         struct jsm_channel *channel =
  98                 container_of(port, struct jsm_channel, uart_port);
  99
 100         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 101
 102         if (mctrl & TIOCM_RTS)
 103                 channel->ch_mostat |= UART_MCR_RTS;
 104         else
 105                 channel->ch_mostat &= ~UART_MCR_RTS;
 106
 107         if (mctrl & TIOCM_DTR)
 108                 channel->ch_mostat |= UART_MCR_DTR;
 109         else
 110                 channel->ch_mostat &= ~UART_MCR_DTR;
 111
 112         channel->ch_bd->bd_ops->assert_modem_signals(channel);
 113
 114         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 115         udelay(10);
 116 }
 117
 118 /*
 119  * jsm_tty_write()
 120  *
 121  * Take data from the user or kernel and send it out to the FEP.
 122  * In here exists all the Transparent Print magic as well.
 123  */
 124 static void jsm_tty_write(struct uart_port *port)
 125 {
 126         struct jsm_channel *channel;
 127         channel = container_of(port, struct jsm_channel, uart_port);
 128         channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
 129 }
 130
 131 static void jsm_tty_start_tx(struct uart_port *port)
 132 {
 133         struct jsm_channel *channel =
 134                 container_of(port, struct jsm_channel, uart_port);
 135
 136         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 137
 138         channel->ch_flags &= ~(CH_STOP);
 139         jsm_tty_write(port);
 140
 141         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 142 }
 143
 144 static void jsm_tty_stop_tx(struct uart_port *port)
 145 {
 146         struct jsm_channel *channel =
 147                 container_of(port, struct jsm_channel, uart_port);
 148
 149         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 150
 151         channel->ch_flags |= (CH_STOP);
 152
 153         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 154 }
 155
 156 static void jsm_tty_send_xchar(struct uart_port *port, char ch)
 157 {
 158         unsigned long lock_flags;
 159         struct jsm_channel *channel =
 160                 container_of(port, struct jsm_channel, uart_port);
 161         struct ktermios *termios;
 162
 163         spin_lock_irqsave(&port->lock, lock_flags);
 164         termios = &port->state->port.tty->termios;
 165         if (ch == termios->c_cc[VSTART])
 166                 channel->ch_bd->bd_ops->send_start_character(channel);
 167
 168         if (ch == termios->c_cc[VSTOP])
 169                 channel->ch_bd->bd_ops->send_stop_character(channel);
 170         spin_unlock_irqrestore(&port->lock, lock_flags);
 171 }
 172
 173 static void jsm_tty_stop_rx(struct uart_port *port)
 174 {
 175         struct jsm_channel *channel =
 176                 container_of(port, struct jsm_channel, uart_port);
 177
 178         channel->ch_bd->bd_ops->disable_receiver(channel);
 179 }
 180
 181 static void jsm_tty_break(struct uart_port *port, int break_state)
 182 {
 183         unsigned long lock_flags;
 184         struct jsm_channel *channel =
 185                 container_of(port, struct jsm_channel, uart_port);
 186
 187         spin_lock_irqsave(&port->lock, lock_flags);
 188         if (break_state == -1)
 189                 channel->ch_bd->bd_ops->send_break(channel);
 190         else
 191                 channel->ch_bd->bd_ops->clear_break(channel);
 192
 193         spin_unlock_irqrestore(&port->lock, lock_flags);
 194 }
 195
 196 static int jsm_tty_open(struct uart_port *port)
 197 {
 198         struct jsm_board *brd;
 199         struct jsm_channel *channel =
 200                 container_of(port, struct jsm_channel, uart_port);
 201         struct ktermios *termios;
 202
 203         /* Get board pointer from our array of majors we have allocated */
 204         brd = channel->ch_bd;
 205
 206         /*
 207          * Allocate channel buffers for read/write/error.
 208          * Set flag, so we don't get trounced on.
 209          */
 210         channel->ch_flags |= (CH_OPENING);
 211
 212         /* Drop locks, as malloc with GFP_KERNEL can sleep */
 213
 214         if (!channel->ch_rqueue) {
 215                 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
 216                 if (!channel->ch_rqueue) {
 217                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 218                                 "unable to allocate read queue buf\n");
 219                         return -ENOMEM;
 220                 }
 221         }
 222         if (!channel->ch_equeue) {
 223                 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
 224                 if (!channel->ch_equeue) {
 225                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 226                                 "unable to allocate error queue buf\n");
 227                         return -ENOMEM;
 228                 }
 229         }
 230
 231         channel->ch_flags &= ~(CH_OPENING);
 232         /*
 233          * Initialize if neither terminal is open.
 234          */
 235         jsm_dbg(OPEN, &channel->ch_bd->pci_dev,
 236                 "jsm_open: initializing channel in open...\n");
 237
 238         /*
 239          * Flush input queues.
 240          */
 241         channel->ch_r_head = channel->ch_r_tail = 0;
 242         channel->ch_e_head = channel->ch_e_tail = 0;
 243
 244         brd->bd_ops->flush_uart_write(channel);
 245         brd->bd_ops->flush_uart_read(channel);
 246
 247         channel->ch_flags = 0;
 248         channel->ch_cached_lsr = 0;
 249         channel->ch_stops_sent = 0;
 250
 251         termios = &port->state->port.tty->termios;
 252         channel->ch_c_cflag     = termios->c_cflag;
 253         channel->ch_c_iflag     = termios->c_iflag;
 254         channel->ch_c_oflag     = termios->c_oflag;
 255         channel->ch_c_lflag     = termios->c_lflag;
 256         channel->ch_startc      = termios->c_cc[VSTART];
 257         channel->ch_stopc       = termios->c_cc[VSTOP];
 258
 259         /* Tell UART to init itself */
 260         brd->bd_ops->uart_init(channel);
 261
 262         /*
 263          * Run param in case we changed anything
 264          */
 265         brd->bd_ops->param(channel);
 266
 267         jsm_carrier(channel);
 268
 269         channel->ch_open_count++;
 270
 271         jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
 272         return 0;
 273 }
 274
 275 static void jsm_tty_close(struct uart_port *port)
 276 {
 277         struct jsm_board *bd;
 278         struct ktermios *ts;
 279         struct jsm_channel *channel =
 280                 container_of(port, struct jsm_channel, uart_port);
 281
 282         jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");
 283
 284         bd = channel->ch_bd;
 285         ts = &port->state->port.tty->termios;
 286
 287         channel->ch_flags &= ~(CH_STOPI);
 288
 289         channel->ch_open_count--;
 290
 291         /*
 292          * If we have HUPCL set, lower DTR and RTS
 293          */
 294         if (channel->ch_c_cflag & HUPCL) {
 295                 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev,
 296                         "Close. HUPCL set, dropping DTR/RTS\n");
 297
 298                 /* Drop RTS/DTR */
 299                 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
 300                 bd->bd_ops->assert_modem_signals(channel);
 301         }
 302
 303         /* Turn off UART interrupts for this port */
 304         channel->ch_bd->bd_ops->uart_off(channel);
 305
 306         jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "finish\n");
 307 }
 308
 309 static void jsm_tty_set_termios(struct uart_port *port,
 310                                  struct ktermios *termios,
 311                                  struct ktermios *old_termios)
 312 {
 313         unsigned long lock_flags;
 314         struct jsm_channel *channel =
 315                 container_of(port, struct jsm_channel, uart_port);
 316
 317         spin_lock_irqsave(&port->lock, lock_flags);
 318         channel->ch_c_cflag     = termios->c_cflag;
 319         channel->ch_c_iflag     = termios->c_iflag;
 320         channel->ch_c_oflag     = termios->c_oflag;
 321         channel->ch_c_lflag     = termios->c_lflag;
 322         channel->ch_startc      = termios->c_cc[VSTART];
 323         channel->ch_stopc       = termios->c_cc[VSTOP];
 324
 325         channel->ch_bd->bd_ops->param(channel);
 326         jsm_carrier(channel);
 327         spin_unlock_irqrestore(&port->lock, lock_flags);
 328 }
 329
 330 static const char *jsm_tty_type(struct uart_port *port)
 331 {
 332         return "jsm";
 333 }
 334
 335 static void jsm_tty_release_port(struct uart_port *port)
 336 {
 337 }
 338
 339 static int jsm_tty_request_port(struct uart_port *port)
 340 {
 341         return 0;
 342 }
 343
 344 static void jsm_config_port(struct uart_port *port, int flags)
 345 {
 346         port->type = PORT_JSM;
 347 }
 348
 349 static const struct uart_ops jsm_ops = {
 350         .tx_empty       = jsm_tty_tx_empty,
 351         .set_mctrl      = jsm_tty_set_mctrl,
 352         .get_mctrl      = jsm_tty_get_mctrl,
 353         .stop_tx        = jsm_tty_stop_tx,
 354         .start_tx       = jsm_tty_start_tx,
 355         .send_xchar     = jsm_tty_send_xchar,
 356         .stop_rx        = jsm_tty_stop_rx,
 357         .break_ctl      = jsm_tty_break,
 358         .startup        = jsm_tty_open,
 359         .shutdown       = jsm_tty_close,
 360         .set_termios    = jsm_tty_set_termios,
 361         .type           = jsm_tty_type,
 362         .release_port   = jsm_tty_release_port,
 363         .request_port   = jsm_tty_request_port,
 364         .config_port    = jsm_config_port,
 365 };
 366
 367 /*
 368  * jsm_tty_init()
 369  *
 370  * Init the tty subsystem.  Called once per board after board has been
 371  * downloaded and init'ed.
 372  */
 373 int jsm_tty_init(struct jsm_board *brd)
 374 {
 375         int i;
 376         void __iomem *vaddr;
 377         struct jsm_channel *ch;
 378
 379         if (!brd)
 380                 return -ENXIO;
 381
 382         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 383
 384         /*
 385          * Initialize board structure elements.
 386          */
 387
 388         brd->nasync = brd->maxports;
 389
 390         /*
 391          * Allocate channel memory that might not have been allocated
 392          * when the driver was first loaded.
 393          */
 394         for (i = 0; i < brd->nasync; i++) {
 395                 if (!brd->channels[i]) {
 396
 397                         /*
 398                          * Okay to malloc with GFP_KERNEL, we are not at
 399                          * interrupt context, and there are no locks held.
 400                          */
 401                         brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
 402                         if (!brd->channels[i]) {
 403                                 jsm_dbg(CORE, &brd->pci_dev,
 404                                         "%s:%d Unable to allocate memory for channel struct\n",
 405                                         __FILE__, __LINE__);
 406                         }
 407                 }
 408         }
 409
 410         ch = brd->channels[0];
 411         vaddr = brd->re_map_membase;
 412
 413         /* Set up channel variables */
 414         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 415
 416                 if (!brd->channels[i])
 417                         continue;
 418
 419                 spin_lock_init(&ch->ch_lock);
 420
 421                 if (brd->bd_uart_offset == 0x200)
 422                         ch->ch_neo_uart =  vaddr + (brd->bd_uart_offset * i);
 423                 else
 424                         ch->ch_cls_uart =  vaddr + (brd->bd_uart_offset * i);
 425
 426                 ch->ch_bd = brd;
 427                 ch->ch_portnum = i;
 428
 429                 /* .25 second delay */
 430                 ch->ch_close_delay = 250;
 431
 432                 init_waitqueue_head(&ch->ch_flags_wait);
 433         }
 434
 435         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 436         return 0;
 437 }
 438
 439 int jsm_uart_port_init(struct jsm_board *brd)
 440 {
 441         int i, rc;
 442         unsigned int line;
 443         struct jsm_channel *ch;
 444
 445         if (!brd)
 446                 return -ENXIO;
 447
 448         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 449
 450         /*
 451          * Initialize board structure elements.
 452          */
 453
 454         brd->nasync = brd->maxports;
 455
 456         /* Set up channel variables */
 457         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 458
 459                 if (!brd->channels[i])
 460                         continue;
 461
 462                 brd->channels[i]->uart_port.irq = brd->irq;
 463                 brd->channels[i]->uart_port.uartclk = 14745600;
 464                 brd->channels[i]->uart_port.type = PORT_JSM;
 465                 brd->channels[i]->uart_port.iotype = UPIO_MEM;
 466                 brd->channels[i]->uart_port.membase = brd->re_map_membase;
 467                 brd->channels[i]->uart_port.fifosize = 16;
 468                 brd->channels[i]->uart_port.ops = &jsm_ops;
 469                 line = find_first_zero_bit(linemap, MAXLINES);
 470                 if (line >= MAXLINES) {
 471                         printk(KERN_INFO "jsm: linemap is full, added device failed\n");
 472                         continue;
 473                 } else
 474                         set_bit(line, linemap);
 475                 brd->channels[i]->uart_port.line = line;
 476                 rc = uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port);
 477                 if (rc){
 478                         printk(KERN_INFO "jsm: Port %d failed. Aborting...\n", i);
 479                         return rc;
 480                 }
 481                 else
 482                         printk(KERN_INFO "jsm: Port %d added\n", i);
 483         }
 484
 485         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 486         return 0;
 487 }
 488
 489 int jsm_remove_uart_port(struct jsm_board *brd)
 490 {
 491         int i;
 492         struct jsm_channel *ch;
 493
 494         if (!brd)
 495                 return -ENXIO;
 496
 497         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 498
 499         /*
 500          * Initialize board structure elements.
 501          */
 502
 503         brd->nasync = brd->maxports;
 504
 505         /* Set up channel variables */
 506         for (i = 0; i < brd->nasync; i++) {
 507
 508                 if (!brd->channels[i])
 509                         continue;
 510
 511                 ch = brd->channels[i];
 512
 513                 clear_bit(ch->uart_port.line, linemap);
 514                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 515         }
 516
 517         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 518         return 0;
 519 }
 520
 521 void jsm_input(struct jsm_channel *ch)
 522 {
 523         struct jsm_board *bd;
 524         struct tty_struct *tp;
 525         struct tty_port *port;
 526         u32 rmask;
 527         u16 head;
 528         u16 tail;
 529         int data_len;
 530         unsigned long lock_flags;
 531         int len = 0;
 532         int s = 0;
 533         int i = 0;
 534
 535         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 536
 537         if (!ch)
 538                 return;
 539
 540         port = &ch->uart_port.state->port;
 541         tp = port->tty;
 542
 543         bd = ch->ch_bd;
 544         if(!bd)
 545                 return;
 546
 547         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 548
 549         /*
 550          *Figure the number of characters in the buffer.
 551          *Exit immediately if none.
 552          */
 553
 554         rmask = RQUEUEMASK;
 555
 556         head = ch->ch_r_head & rmask;
 557         tail = ch->ch_r_tail & rmask;
 558
 559         data_len = (head - tail) & rmask;
 560         if (data_len == 0) {
 561                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 562                 return;
 563         }
 564
 565         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 566
 567         /*
 568          *If the device is not open, or CREAD is off, flush
 569          *input data and return immediately.
 570          */
 571         if (!tp || !C_CREAD(tp)) {
 572
 573                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 574                         "input. dropping %d bytes on port %d...\n",
 575                         data_len, ch->ch_portnum);
 576                 ch->ch_r_head = tail;
 577
 578                 /* Force queue flow control to be released, if needed */
 579                 jsm_check_queue_flow_control(ch);
 580
 581                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 582                 return;
 583         }
 584
 585         /*
 586          * If we are throttled, simply don't read any data.
 587          */
 588         if (ch->ch_flags & CH_STOPI) {
 589                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 590                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 591                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 592                         ch->ch_portnum, head, tail);
 593                 return;
 594         }
 595
 596         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");
 597
 598         len = tty_buffer_request_room(port, data_len);
 599
 600         /*
 601          * len now contains the most amount of data we can copy,
 602          * bounded either by the flip buffer size or the amount
 603          * of data the card actually has pending...
 604          */
 605         while (len) {
 606                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 607                 s = min(s, len);
 608
 609                 if (s <= 0)
 610                         break;
 611
 612                         /*
 613                          * If conditions are such that ld needs to see all
 614                          * UART errors, we will have to walk each character
 615                          * and error byte and send them to the buffer one at
 616                          * a time.
 617                          */
 618
 619                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 620                         for (i = 0; i < s; i++) {
 621                                 /*
 622                                  * Give the Linux ld the flags in the
 623                                  * format it likes.
 624                                  */
 625                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 626                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 627                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 628                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 629                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 630                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 631                                 else
 632                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 633                         }
 634                 } else {
 635                         tty_insert_flip_string(port, ch->ch_rqueue + tail, s);
 636                 }
 637                 tail += s;
 638                 len -= s;
 639                 /* Flip queue if needed */
 640                 tail &= rmask;
 641         }
 642
 643         ch->ch_r_tail = tail & rmask;
 644         ch->ch_e_tail = tail & rmask;
 645         jsm_check_queue_flow_control(ch);
 646         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 647
 648         /* Tell the tty layer its okay to "eat" the data now */
 649         tty_flip_buffer_push(port);
 650
 651         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
 652 }
 653
 654 static void jsm_carrier(struct jsm_channel *ch)
 655 {
 656         struct jsm_board *bd;
 657
 658         int virt_carrier = 0;
 659         int phys_carrier = 0;
 660
 661         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");
 662         if (!ch)
 663                 return;
 664
 665         bd = ch->ch_bd;
 666
 667         if (!bd)
 668                 return;
 669
 670         if (ch->ch_mistat & UART_MSR_DCD) {
 671                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "mistat: %x D_CD: %x\n",
 672                         ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 673                 phys_carrier = 1;
 674         }
 675
 676         if (ch->ch_c_cflag & CLOCAL)
 677                 virt_carrier = 1;
 678
 679         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "DCD: physical: %d virt: %d\n",
 680                 phys_carrier, virt_carrier);
 681
 682         /*
 683          * Test for a VIRTUAL carrier transition to HIGH.
 684          */
 685         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 686
 687                 /*
 688                  * When carrier rises, wake any threads waiting
 689                  * for carrier in the open routine.
 690                  */
 691
 692                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "carrier: virt DCD rose\n");
 693
 694                 if (waitqueue_active(&(ch->ch_flags_wait)))
 695                         wake_up_interruptible(&ch->ch_flags_wait);
 696         }
 697
 698         /*
 699          * Test for a PHYSICAL carrier transition to HIGH.
 700          */
 701         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 702
 703                 /*
 704                  * When carrier rises, wake any threads waiting
 705                  * for carrier in the open routine.
 706                  */
 707
 708                 jsm_dbg(CARR, &ch->ch_bd->pci_dev,
 709                         "carrier: physical DCD rose\n");
 710
 711                 if (waitqueue_active(&(ch->ch_flags_wait)))
 712                         wake_up_interruptible(&ch->ch_flags_wait);
 713         }
 714
 715         /*
 716          *  Test for a PHYSICAL transition to low, so long as we aren't
 717          *  currently ignoring physical transitions (which is what "virtual
 718          *  carrier" indicates).
 719          *
 720          *  The transition of the virtual carrier to low really doesn't
 721          *  matter... it really only means "ignore carrier state", not
 722          *  "make pretend that carrier is there".
 723          */
 724         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 725                         && (phys_carrier == 0)) {
 726                 /*
 727                  *      When carrier drops:
 728                  *
 729                  *      Drop carrier on all open units.
 730                  *
 731                  *      Flush queues, waking up any task waiting in the
 732                  *      line discipline.
 733                  *
 734                  *      Send a hangup to the control terminal.
 735                  *
 736                  *      Enable all select calls.
 737                  */
 738                 if (waitqueue_active(&(ch->ch_flags_wait)))
 739                         wake_up_interruptible(&ch->ch_flags_wait);
 740         }
 741
 742         /*
 743          *  Make sure that our cached values reflect the current reality.
 744          */
 745         if (virt_carrier == 1)
 746                 ch->ch_flags |= CH_FCAR;
 747         else
 748                 ch->ch_flags &= ~CH_FCAR;
 749
 750         if (phys_carrier == 1)
 751                 ch->ch_flags |= CH_CD;
 752         else
 753                 ch->ch_flags &= ~CH_CD;
 754 }
 755
 756
 757 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 758 {
 759         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 760         int qleft;
 761
 762         /* Store how much space we have left in the queue */
 763         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 764                 qleft += RQUEUEMASK + 1;
 765
 766         /*
 767          * Check to see if we should enforce flow control on our queue because
 768          * the ld (or user) isn't reading data out of our queue fast enuf.
 769          *
 770          * NOTE: This is done based on what the current flow control of the
 771          * port is set for.
 772          *
 773          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 774          *      This will cause the UART's FIFO to back up, and force
 775          *      the RTS signal to be dropped.
 776          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 777          *      the other side, in hopes it will stop sending data to us.
 778          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 779          *      that gets sent into us when the queue fills up.
 780          */
 781         if (qleft < 256) {
 782                 /* HWFLOW */
 783                 if (ch->ch_c_cflag & CRTSCTS) {
 784                         if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
 785                                 bd_ops->disable_receiver(ch);
 786                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 787                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 788                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts\n",
 789                                         qleft);
 790                         }
 791                 }
 792                 /* SWFLOW */
 793                 else if (ch->ch_c_iflag & IXOFF) {
 794                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 795                                 bd_ops->send_stop_character(ch);
 796                                 ch->ch_stops_sent++;
 797                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 798                                         "Sending stop char! Times sent: %x\n",
 799                                         ch->ch_stops_sent);
 800                         }
 801                 }
 802         }
 803
 804         /*
 805          * Check to see if we should unenforce flow control because
 806          * ld (or user) finally read enuf data out of our queue.
 807          *
 808          * NOTE: This is done based on what the current flow control of the
 809          * port is set for.
 810          *
 811          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 812          *      This will cause the UART's FIFO to raise RTS back up,
 813          *      which will allow the other side to start sending data again.
 814          * 2) SWFLOW (IXOFF) - Send a start character to
 815          *      the other side, so it will start sending data to us again.
 816          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 817          *      other side, we don't need to do anything now.
 818          */
 819         if (qleft > (RQUEUESIZE / 2)) {
 820                 /* HWFLOW */
 821                 if (ch->ch_c_cflag & CRTSCTS) {
 822                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 823                                 bd_ops->enable_receiver(ch);
 824                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 825                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 826                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts\n",
 827                                         qleft);
 828                         }
 829                 }
 830                 /* SWFLOW */
 831                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 832                         ch->ch_stops_sent = 0;
 833                         bd_ops->send_start_character(ch);
 834                         jsm_dbg(READ, &ch->ch_bd->pci_dev,
 835                                 "Sending start char!\n");
 836                 }
 837         }
 838 }