drivers/tty/serial/jsm/jsm_tty.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /************************************************************************
   3  * Copyright 2003 Digi International (www.digi.com)
   4  *
   5  * Copyright (C) 2004 IBM Corporation. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE.  See the GNU General Public License for more details.
  16  *
  17  * Contact Information:
  18  * Scott H Kilau <Scott_Kilau@digi.com>
  19  * Ananda Venkatarman <mansarov@us.ibm.com>
  20  * Modifications:
  21  * 01/19/06:    changed jsm_input routine to use the dynamically allocated
  22  *              tty_buffer changes. Contributors: Scott Kilau and Ananda V.
  23  ***********************************************************************/
  24 #include <linux/tty.h>
  25 #include <linux/tty_flip.h>
  26 #include <linux/serial_reg.h>
  27 #include <linux/delay.h>        /* For udelay */
  28 #include <linux/pci.h>
  29 #include <linux/slab.h>
  30
  31 #include "jsm.h"
  32
  33 static DECLARE_BITMAP(linemap, MAXLINES);
  34
  35 static void jsm_carrier(struct jsm_channel *ch);
  36
  37 static inline int jsm_get_mstat(struct jsm_channel *ch)
  38 {
  39         unsigned char mstat;
  40         int result;
  41
  42         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "start\n");
  43
  44         mstat = (ch->ch_mostat | ch->ch_mistat);
  45
  46         result = 0;
  47
  48         if (mstat & UART_MCR_DTR)
  49                 result |= TIOCM_DTR;
  50         if (mstat & UART_MCR_RTS)
  51                 result |= TIOCM_RTS;
  52         if (mstat & UART_MSR_CTS)
  53                 result |= TIOCM_CTS;
  54         if (mstat & UART_MSR_DSR)
  55                 result |= TIOCM_DSR;
  56         if (mstat & UART_MSR_RI)
  57                 result |= TIOCM_RI;
  58         if (mstat & UART_MSR_DCD)
  59                 result |= TIOCM_CD;
  60
  61         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
  62         return result;
  63 }
  64
  65 static unsigned int jsm_tty_tx_empty(struct uart_port *port)
  66 {
  67         return TIOCSER_TEMT;
  68 }
  69
  70 /*
  71  * Return modem signals to ld.
  72  */
  73 static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
  74 {
  75         int result;
  76         struct jsm_channel *channel =
  77                 container_of(port, struct jsm_channel, uart_port);
  78
  79         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
  80
  81         result = jsm_get_mstat(channel);
  82
  83         if (result < 0)
  84                 return -ENXIO;
  85
  86         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
  87
  88         return result;
  89 }
  90
  91 /*
  92  * jsm_set_modem_info()
  93  *
  94  * Set modem signals, called by ld.
  95  */
  96 static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)
  97 {
  98         struct jsm_channel *channel =
  99                 container_of(port, struct jsm_channel, uart_port);
 100
 101         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 102
 103         if (mctrl & TIOCM_RTS)
 104                 channel->ch_mostat |= UART_MCR_RTS;
 105         else
 106                 channel->ch_mostat &= ~UART_MCR_RTS;
 107
 108         if (mctrl & TIOCM_DTR)
 109                 channel->ch_mostat |= UART_MCR_DTR;
 110         else
 111                 channel->ch_mostat &= ~UART_MCR_DTR;
 112
 113         channel->ch_bd->bd_ops->assert_modem_signals(channel);
 114
 115         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 116         udelay(10);
 117 }
 118
 119 /*
 120  * jsm_tty_write()
 121  *
 122  * Take data from the user or kernel and send it out to the FEP.
 123  * In here exists all the Transparent Print magic as well.
 124  */
 125 static void jsm_tty_write(struct uart_port *port)
 126 {
 127         struct jsm_channel *channel;
 128
 129         channel = container_of(port, struct jsm_channel, uart_port);
 130         channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
 131 }
 132
 133 static void jsm_tty_start_tx(struct uart_port *port)
 134 {
 135         struct jsm_channel *channel =
 136                 container_of(port, struct jsm_channel, uart_port);
 137
 138         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 139
 140         channel->ch_flags &= ~(CH_STOP);
 141         jsm_tty_write(port);
 142
 143         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 144 }
 145
 146 static void jsm_tty_stop_tx(struct uart_port *port)
 147 {
 148         struct jsm_channel *channel =
 149                 container_of(port, struct jsm_channel, uart_port);
 150
 151         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
 152
 153         channel->ch_flags |= (CH_STOP);
 154
 155         jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
 156 }
 157
 158 static void jsm_tty_send_xchar(struct uart_port *port, char ch)
 159 {
 160         unsigned long lock_flags;
 161         struct jsm_channel *channel =
 162                 container_of(port, struct jsm_channel, uart_port);
 163         struct ktermios *termios;
 164
 165         spin_lock_irqsave(&port->lock, lock_flags);
 166         termios = &port->state->port.tty->termios;
 167         if (ch == termios->c_cc[VSTART])
 168                 channel->ch_bd->bd_ops->send_start_character(channel);
 169
 170         if (ch == termios->c_cc[VSTOP])
 171                 channel->ch_bd->bd_ops->send_stop_character(channel);
 172         spin_unlock_irqrestore(&port->lock, lock_flags);
 173 }
 174
 175 static void jsm_tty_stop_rx(struct uart_port *port)
 176 {
 177         struct jsm_channel *channel =
 178                 container_of(port, struct jsm_channel, uart_port);
 179
 180         channel->ch_bd->bd_ops->disable_receiver(channel);
 181 }
 182
 183 static void jsm_tty_break(struct uart_port *port, int break_state)
 184 {
 185         unsigned long lock_flags;
 186         struct jsm_channel *channel =
 187                 container_of(port, struct jsm_channel, uart_port);
 188
 189         spin_lock_irqsave(&port->lock, lock_flags);
 190         if (break_state == -1)
 191                 channel->ch_bd->bd_ops->send_break(channel);
 192         else
 193                 channel->ch_bd->bd_ops->clear_break(channel);
 194
 195         spin_unlock_irqrestore(&port->lock, lock_flags);
 196 }
 197
 198 static int jsm_tty_open(struct uart_port *port)
 199 {
 200         struct jsm_board *brd;
 201         struct jsm_channel *channel =
 202                 container_of(port, struct jsm_channel, uart_port);
 203         struct ktermios *termios;
 204
 205         /* Get board pointer from our array of majors we have allocated */
 206         brd = channel->ch_bd;
 207
 208         /*
 209          * Allocate channel buffers for read/write/error.
 210          * Set flag, so we don't get trounced on.
 211          */
 212         channel->ch_flags |= (CH_OPENING);
 213
 214         /* Drop locks, as malloc with GFP_KERNEL can sleep */
 215
 216         if (!channel->ch_rqueue) {
 217                 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
 218                 if (!channel->ch_rqueue) {
 219                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 220                                 "unable to allocate read queue buf\n");
 221                         return -ENOMEM;
 222                 }
 223         }
 224         if (!channel->ch_equeue) {
 225                 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
 226                 if (!channel->ch_equeue) {
 227                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 228                                 "unable to allocate error queue buf\n");
 229                         return -ENOMEM;
 230                 }
 231         }
 232
 233         channel->ch_flags &= ~(CH_OPENING);
 234         /*
 235          * Initialize if neither terminal is open.
 236          */
 237         jsm_dbg(OPEN, &channel->ch_bd->pci_dev,
 238                 "jsm_open: initializing channel in open...\n");
 239
 240         /*
 241          * Flush input queues.
 242          */
 243         channel->ch_r_head = channel->ch_r_tail = 0;
 244         channel->ch_e_head = channel->ch_e_tail = 0;
 245
 246         brd->bd_ops->flush_uart_write(channel);
 247         brd->bd_ops->flush_uart_read(channel);
 248
 249         channel->ch_flags = 0;
 250         channel->ch_cached_lsr = 0;
 251         channel->ch_stops_sent = 0;
 252
 253         termios = &port->state->port.tty->termios;
 254         channel->ch_c_cflag     = termios->c_cflag;
 255         channel->ch_c_iflag     = termios->c_iflag;
 256         channel->ch_c_oflag     = termios->c_oflag;
 257         channel->ch_c_lflag     = termios->c_lflag;
 258         channel->ch_startc      = termios->c_cc[VSTART];
 259         channel->ch_stopc       = termios->c_cc[VSTOP];
 260
 261         /* Tell UART to init itself */
 262         brd->bd_ops->uart_init(channel);
 263
 264         /*
 265          * Run param in case we changed anything
 266          */
 267         brd->bd_ops->param(channel);
 268
 269         jsm_carrier(channel);
 270
 271         channel->ch_open_count++;
 272
 273         jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
 274         return 0;
 275 }
 276
 277 static void jsm_tty_close(struct uart_port *port)
 278 {
 279         struct jsm_board *bd;
 280         struct jsm_channel *channel =
 281                 container_of(port, struct jsm_channel, uart_port);
 282
 283         jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");
 284
 285         bd = channel->ch_bd;
 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                 } else
 481                         printk(KERN_INFO "jsm: Port %d added\n", i);
 482         }
 483
 484         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 485         return 0;
 486 }
 487
 488 int jsm_remove_uart_port(struct jsm_board *brd)
 489 {
 490         int i;
 491         struct jsm_channel *ch;
 492
 493         if (!brd)
 494                 return -ENXIO;
 495
 496         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 497
 498         /*
 499          * Initialize board structure elements.
 500          */
 501
 502         brd->nasync = brd->maxports;
 503
 504         /* Set up channel variables */
 505         for (i = 0; i < brd->nasync; i++) {
 506
 507                 if (!brd->channels[i])
 508                         continue;
 509
 510                 ch = brd->channels[i];
 511
 512                 clear_bit(ch->uart_port.line, linemap);
 513                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 514         }
 515
 516         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 517         return 0;
 518 }
 519
 520 void jsm_input(struct jsm_channel *ch)
 521 {
 522         struct jsm_board *bd;
 523         struct tty_struct *tp;
 524         struct tty_port *port;
 525         u32 rmask;
 526         u16 head;
 527         u16 tail;
 528         int data_len;
 529         unsigned long lock_flags;
 530         int len = 0;
 531         int s = 0;
 532         int i = 0;
 533
 534         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 535
 536         if (!ch)
 537                 return;
 538
 539         port = &ch->uart_port.state->port;
 540         tp = port->tty;
 541
 542         bd = ch->ch_bd;
 543         if (!bd)
 544                 return;
 545
 546         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 547
 548         /*
 549          *Figure the number of characters in the buffer.
 550          *Exit immediately if none.
 551          */
 552
 553         rmask = RQUEUEMASK;
 554
 555         head = ch->ch_r_head & rmask;
 556         tail = ch->ch_r_tail & rmask;
 557
 558         data_len = (head - tail) & rmask;
 559         if (data_len == 0) {
 560                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 561                 return;
 562         }
 563
 564         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 565
 566         /*
 567          *If the device is not open, or CREAD is off, flush
 568          *input data and return immediately.
 569          */
 570         if (!tp || !C_CREAD(tp)) {
 571
 572                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 573                         "input. dropping %d bytes on port %d...\n",
 574                         data_len, ch->ch_portnum);
 575                 ch->ch_r_head = tail;
 576
 577                 /* Force queue flow control to be released, if needed */
 578                 jsm_check_queue_flow_control(ch);
 579
 580                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 581                 return;
 582         }
 583
 584         /*
 585          * If we are throttled, simply don't read any data.
 586          */
 587         if (ch->ch_flags & CH_STOPI) {
 588                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 589                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 590                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 591                         ch->ch_portnum, head, tail);
 592                 return;
 593         }
 594
 595         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");
 596
 597         len = tty_buffer_request_room(port, data_len);
 598
 599         /*
 600          * len now contains the most amount of data we can copy,
 601          * bounded either by the flip buffer size or the amount
 602          * of data the card actually has pending...
 603          */
 604         while (len) {
 605                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 606                 s = min(s, len);
 607
 608                 if (s <= 0)
 609                         break;
 610
 611                         /*
 612                          * If conditions are such that ld needs to see all
 613                          * UART errors, we will have to walk each character
 614                          * and error byte and send them to the buffer one at
 615                          * a time.
 616                          */
 617
 618                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 619                         for (i = 0; i < s; i++) {
 620                                 /*
 621                                  * Give the Linux ld the flags in the
 622                                  * format it likes.
 623                                  */
 624                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 625                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 626                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 627                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 628                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 629                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 630                                 else
 631                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 632                         }
 633                 } else {
 634                         tty_insert_flip_string(port, ch->ch_rqueue + tail, s);
 635                 }
 636                 tail += s;
 637                 len -= s;
 638                 /* Flip queue if needed */
 639                 tail &= rmask;
 640         }
 641
 642         ch->ch_r_tail = tail & rmask;
 643         ch->ch_e_tail = tail & rmask;
 644         jsm_check_queue_flow_control(ch);
 645         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 646
 647         /* Tell the tty layer its okay to "eat" the data now */
 648         tty_flip_buffer_push(port);
 649
 650         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
 651 }
 652
 653 static void jsm_carrier(struct jsm_channel *ch)
 654 {
 655         struct jsm_board *bd;
 656
 657         int virt_carrier = 0;
 658         int phys_carrier = 0;
 659
 660         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");
 661         if (!ch)
 662                 return;
 663
 664         bd = ch->ch_bd;
 665
 666         if (!bd)
 667                 return;
 668
 669         if (ch->ch_mistat & UART_MSR_DCD) {
 670                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "mistat: %x D_CD: %x\n",
 671                         ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 672                 phys_carrier = 1;
 673         }
 674
 675         if (ch->ch_c_cflag & CLOCAL)
 676                 virt_carrier = 1;
 677
 678         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "DCD: physical: %d virt: %d\n",
 679                 phys_carrier, virt_carrier);
 680
 681         /*
 682          * Test for a VIRTUAL carrier transition to HIGH.
 683          */
 684         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 685
 686                 /*
 687                  * When carrier rises, wake any threads waiting
 688                  * for carrier in the open routine.
 689                  */
 690
 691                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "carrier: virt DCD rose\n");
 692
 693                 if (waitqueue_active(&(ch->ch_flags_wait)))
 694                         wake_up_interruptible(&ch->ch_flags_wait);
 695         }
 696
 697         /*
 698          * Test for a PHYSICAL carrier transition to HIGH.
 699          */
 700         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 701
 702                 /*
 703                  * When carrier rises, wake any threads waiting
 704                  * for carrier in the open routine.
 705                  */
 706
 707                 jsm_dbg(CARR, &ch->ch_bd->pci_dev,
 708                         "carrier: physical DCD rose\n");
 709
 710                 if (waitqueue_active(&(ch->ch_flags_wait)))
 711                         wake_up_interruptible(&ch->ch_flags_wait);
 712         }
 713
 714         /*
 715          *  Test for a PHYSICAL transition to low, so long as we aren't
 716          *  currently ignoring physical transitions (which is what "virtual
 717          *  carrier" indicates).
 718          *
 719          *  The transition of the virtual carrier to low really doesn't
 720          *  matter... it really only means "ignore carrier state", not
 721          *  "make pretend that carrier is there".
 722          */
 723         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 724                         && (phys_carrier == 0)) {
 725                 /*
 726                  *      When carrier drops:
 727                  *
 728                  *      Drop carrier on all open units.
 729                  *
 730                  *      Flush queues, waking up any task waiting in the
 731                  *      line discipline.
 732                  *
 733                  *      Send a hangup to the control terminal.
 734                  *
 735                  *      Enable all select calls.
 736                  */
 737                 if (waitqueue_active(&(ch->ch_flags_wait)))
 738                         wake_up_interruptible(&ch->ch_flags_wait);
 739         }
 740
 741         /*
 742          *  Make sure that our cached values reflect the current reality.
 743          */
 744         if (virt_carrier == 1)
 745                 ch->ch_flags |= CH_FCAR;
 746         else
 747                 ch->ch_flags &= ~CH_FCAR;
 748
 749         if (phys_carrier == 1)
 750                 ch->ch_flags |= CH_CD;
 751         else
 752                 ch->ch_flags &= ~CH_CD;
 753 }
 754
 755
 756 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 757 {
 758         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 759         int qleft;
 760
 761         /* Store how much space we have left in the queue */
 762         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 763                 qleft += RQUEUEMASK + 1;
 764
 765         /*
 766          * Check to see if we should enforce flow control on our queue because
 767          * the ld (or user) isn't reading data out of our queue fast enuf.
 768          *
 769          * NOTE: This is done based on what the current flow control of the
 770          * port is set for.
 771          *
 772          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 773          *      This will cause the UART's FIFO to back up, and force
 774          *      the RTS signal to be dropped.
 775          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 776          *      the other side, in hopes it will stop sending data to us.
 777          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 778          *      that gets sent into us when the queue fills up.
 779          */
 780         if (qleft < 256) {
 781                 /* HWFLOW */
 782                 if (ch->ch_c_cflag & CRTSCTS) {
 783                         if (!(ch->ch_flags & CH_RECEIVER_OFF)) {
 784                                 bd_ops->disable_receiver(ch);
 785                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 786                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 787                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts\n",
 788                                         qleft);
 789                         }
 790                 }
 791                 /* SWFLOW */
 792                 else if (ch->ch_c_iflag & IXOFF) {
 793                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 794                                 bd_ops->send_stop_character(ch);
 795                                 ch->ch_stops_sent++;
 796                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 797                                         "Sending stop char! Times sent: %x\n",
 798                                         ch->ch_stops_sent);
 799                         }
 800                 }
 801         }
 802
 803         /*
 804          * Check to see if we should unenforce flow control because
 805          * ld (or user) finally read enuf data out of our queue.
 806          *
 807          * NOTE: This is done based on what the current flow control of the
 808          * port is set for.
 809          *
 810          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 811          *      This will cause the UART's FIFO to raise RTS back up,
 812          *      which will allow the other side to start sending data again.
 813          * 2) SWFLOW (IXOFF) - Send a start character to
 814          *      the other side, so it will start sending data to us again.
 815          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 816          *      other side, we don't need to do anything now.
 817          */
 818         if (qleft > (RQUEUESIZE / 2)) {
 819                 /* HWFLOW */
 820                 if (ch->ch_c_cflag & CRTSCTS) {
 821                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 822                                 bd_ops->enable_receiver(ch);
 823                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 824                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 825                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts\n",
 826                                         qleft);
 827                         }
 828                 }
 829                 /* SWFLOW */
 830                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 831                         ch->ch_stops_sent = 0;
 832                         bd_ops->send_start_character(ch);
 833                         jsm_dbg(READ, &ch->ch_bd->pci_dev,
 834                                 "Sending start char!\n");
 835                 }
 836         }
 837 }