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         unsigned long lock_flags;
 199         struct jsm_board *brd;
 200         struct jsm_channel *channel =
 201                 container_of(port, struct jsm_channel, uart_port);
 202         struct ktermios *termios;
 203
 204         /* Get board pointer from our array of majors we have allocated */
 205         brd = channel->ch_bd;
 206
 207         /*
 208          * Allocate channel buffers for read/write/error.
 209          * Set flag, so we don't get trounced on.
 210          */
 211         channel->ch_flags |= (CH_OPENING);
 212
 213         /* Drop locks, as malloc with GFP_KERNEL can sleep */
 214
 215         if (!channel->ch_rqueue) {
 216                 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
 217                 if (!channel->ch_rqueue) {
 218                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 219                                 "unable to allocate read queue buf\n");
 220                         return -ENOMEM;
 221                 }
 222         }
 223         if (!channel->ch_equeue) {
 224                 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
 225                 if (!channel->ch_equeue) {
 226                         jsm_dbg(INIT, &channel->ch_bd->pci_dev,
 227                                 "unable to allocate error queue buf\n");
 228                         return -ENOMEM;
 229                 }
 230         }
 231
 232         channel->ch_flags &= ~(CH_OPENING);
 233         /*
 234          * Initialize if neither terminal is open.
 235          */
 236         jsm_dbg(OPEN, &channel->ch_bd->pci_dev,
 237                 "jsm_open: initializing channel in open...\n");
 238
 239         /*
 240          * Flush input queues.
 241          */
 242         channel->ch_r_head = channel->ch_r_tail = 0;
 243         channel->ch_e_head = channel->ch_e_tail = 0;
 244
 245         brd->bd_ops->flush_uart_write(channel);
 246         brd->bd_ops->flush_uart_read(channel);
 247
 248         channel->ch_flags = 0;
 249         channel->ch_cached_lsr = 0;
 250         channel->ch_stops_sent = 0;
 251
 252         spin_lock_irqsave(&port->lock, lock_flags);
 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         spin_unlock_irqrestore(&port->lock, lock_flags);
 273
 274         jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
 275         return 0;
 276 }
 277
 278 static void jsm_tty_close(struct uart_port *port)
 279 {
 280         struct jsm_board *bd;
 281         struct ktermios *ts;
 282         struct jsm_channel *channel =
 283                 container_of(port, struct jsm_channel, uart_port);
 284
 285         jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");
 286
 287         bd = channel->ch_bd;
 288         ts = &port->state->port.tty->termios;
 289
 290         channel->ch_flags &= ~(CH_STOPI);
 291
 292         channel->ch_open_count--;
 293
 294         /*
 295          * If we have HUPCL set, lower DTR and RTS
 296          */
 297         if (channel->ch_c_cflag & HUPCL) {
 298                 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev,
 299                         "Close. HUPCL set, dropping DTR/RTS\n");
 300
 301                 /* Drop RTS/DTR */
 302                 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
 303                 bd->bd_ops->assert_modem_signals(channel);
 304         }
 305
 306         /* Turn off UART interrupts for this port */
 307         channel->ch_bd->bd_ops->uart_off(channel);
 308
 309         jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "finish\n");
 310 }
 311
 312 static void jsm_tty_set_termios(struct uart_port *port,
 313                                  struct ktermios *termios,
 314                                  struct ktermios *old_termios)
 315 {
 316         unsigned long lock_flags;
 317         struct jsm_channel *channel =
 318                 container_of(port, struct jsm_channel, uart_port);
 319
 320         spin_lock_irqsave(&port->lock, lock_flags);
 321         channel->ch_c_cflag     = termios->c_cflag;
 322         channel->ch_c_iflag     = termios->c_iflag;
 323         channel->ch_c_oflag     = termios->c_oflag;
 324         channel->ch_c_lflag     = termios->c_lflag;
 325         channel->ch_startc      = termios->c_cc[VSTART];
 326         channel->ch_stopc       = termios->c_cc[VSTOP];
 327
 328         channel->ch_bd->bd_ops->param(channel);
 329         jsm_carrier(channel);
 330         spin_unlock_irqrestore(&port->lock, lock_flags);
 331 }
 332
 333 static const char *jsm_tty_type(struct uart_port *port)
 334 {
 335         return "jsm";
 336 }
 337
 338 static void jsm_tty_release_port(struct uart_port *port)
 339 {
 340 }
 341
 342 static int jsm_tty_request_port(struct uart_port *port)
 343 {
 344         return 0;
 345 }
 346
 347 static void jsm_config_port(struct uart_port *port, int flags)
 348 {
 349         port->type = PORT_JSM;
 350 }
 351
 352 static struct uart_ops jsm_ops = {
 353         .tx_empty       = jsm_tty_tx_empty,
 354         .set_mctrl      = jsm_tty_set_mctrl,
 355         .get_mctrl      = jsm_tty_get_mctrl,
 356         .stop_tx        = jsm_tty_stop_tx,
 357         .start_tx       = jsm_tty_start_tx,
 358         .send_xchar     = jsm_tty_send_xchar,
 359         .stop_rx        = jsm_tty_stop_rx,
 360         .break_ctl      = jsm_tty_break,
 361         .startup        = jsm_tty_open,
 362         .shutdown       = jsm_tty_close,
 363         .set_termios    = jsm_tty_set_termios,
 364         .type           = jsm_tty_type,
 365         .release_port   = jsm_tty_release_port,
 366         .request_port   = jsm_tty_request_port,
 367         .config_port    = jsm_config_port,
 368 };
 369
 370 /*
 371  * jsm_tty_init()
 372  *
 373  * Init the tty subsystem.  Called once per board after board has been
 374  * downloaded and init'ed.
 375  */
 376 int jsm_tty_init(struct jsm_board *brd)
 377 {
 378         int i;
 379         void __iomem *vaddr;
 380         struct jsm_channel *ch;
 381
 382         if (!brd)
 383                 return -ENXIO;
 384
 385         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 386
 387         /*
 388          * Initialize board structure elements.
 389          */
 390
 391         brd->nasync = brd->maxports;
 392
 393         /*
 394          * Allocate channel memory that might not have been allocated
 395          * when the driver was first loaded.
 396          */
 397         for (i = 0; i < brd->nasync; i++) {
 398                 if (!brd->channels[i]) {
 399
 400                         /*
 401                          * Okay to malloc with GFP_KERNEL, we are not at
 402                          * interrupt context, and there are no locks held.
 403                          */
 404                         brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
 405                         if (!brd->channels[i]) {
 406                                 jsm_dbg(CORE, &brd->pci_dev,
 407                                         "%s:%d Unable to allocate memory for channel struct\n",
 408                                         __FILE__, __LINE__);
 409                         }
 410                 }
 411         }
 412
 413         ch = brd->channels[0];
 414         vaddr = brd->re_map_membase;
 415
 416         /* Set up channel variables */
 417         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 418
 419                 if (!brd->channels[i])
 420                         continue;
 421
 422                 spin_lock_init(&ch->ch_lock);
 423
 424                 if (brd->bd_uart_offset == 0x200)
 425                         ch->ch_neo_uart =  vaddr + (brd->bd_uart_offset * i);
 426                 else
 427                         ch->ch_cls_uart =  vaddr + (brd->bd_uart_offset * i);
 428
 429                 ch->ch_bd = brd;
 430                 ch->ch_portnum = i;
 431
 432                 /* .25 second delay */
 433                 ch->ch_close_delay = 250;
 434
 435                 init_waitqueue_head(&ch->ch_flags_wait);
 436         }
 437
 438         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 439         return 0;
 440 }
 441
 442 int jsm_uart_port_init(struct jsm_board *brd)
 443 {
 444         int i, rc;
 445         unsigned int line;
 446         struct jsm_channel *ch;
 447
 448         if (!brd)
 449                 return -ENXIO;
 450
 451         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 452
 453         /*
 454          * Initialize board structure elements.
 455          */
 456
 457         brd->nasync = brd->maxports;
 458
 459         /* Set up channel variables */
 460         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 461
 462                 if (!brd->channels[i])
 463                         continue;
 464
 465                 brd->channels[i]->uart_port.irq = brd->irq;
 466                 brd->channels[i]->uart_port.uartclk = 14745600;
 467                 brd->channels[i]->uart_port.type = PORT_JSM;
 468                 brd->channels[i]->uart_port.iotype = UPIO_MEM;
 469                 brd->channels[i]->uart_port.membase = brd->re_map_membase;
 470                 brd->channels[i]->uart_port.fifosize = 16;
 471                 brd->channels[i]->uart_port.ops = &jsm_ops;
 472                 line = find_first_zero_bit(linemap, MAXLINES);
 473                 if (line >= MAXLINES) {
 474                         printk(KERN_INFO "jsm: linemap is full, added device failed\n");
 475                         continue;
 476                 } else
 477                         set_bit(line, linemap);
 478                 brd->channels[i]->uart_port.line = line;
 479                 rc = uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port);
 480                 if (rc){
 481                         printk(KERN_INFO "jsm: Port %d failed. Aborting...\n", i);
 482                         return rc;
 483                 }
 484                 else
 485                         printk(KERN_INFO "jsm: Port %d added\n", i);
 486         }
 487
 488         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 489         return 0;
 490 }
 491
 492 int jsm_remove_uart_port(struct jsm_board *brd)
 493 {
 494         int i;
 495         struct jsm_channel *ch;
 496
 497         if (!brd)
 498                 return -ENXIO;
 499
 500         jsm_dbg(INIT, &brd->pci_dev, "start\n");
 501
 502         /*
 503          * Initialize board structure elements.
 504          */
 505
 506         brd->nasync = brd->maxports;
 507
 508         /* Set up channel variables */
 509         for (i = 0; i < brd->nasync; i++) {
 510
 511                 if (!brd->channels[i])
 512                         continue;
 513
 514                 ch = brd->channels[i];
 515
 516                 clear_bit(ch->uart_port.line, linemap);
 517                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 518         }
 519
 520         jsm_dbg(INIT, &brd->pci_dev, "finish\n");
 521         return 0;
 522 }
 523
 524 void jsm_input(struct jsm_channel *ch)
 525 {
 526         struct jsm_board *bd;
 527         struct tty_struct *tp;
 528         struct tty_port *port;
 529         u32 rmask;
 530         u16 head;
 531         u16 tail;
 532         int data_len;
 533         unsigned long lock_flags;
 534         int len = 0;
 535         int n = 0;
 536         int s = 0;
 537         int i = 0;
 538
 539         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 540
 541         if (!ch)
 542                 return;
 543
 544         port = &ch->uart_port.state->port;
 545         tp = port->tty;
 546
 547         bd = ch->ch_bd;
 548         if(!bd)
 549                 return;
 550
 551         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 552
 553         /*
 554          *Figure the number of characters in the buffer.
 555          *Exit immediately if none.
 556          */
 557
 558         rmask = RQUEUEMASK;
 559
 560         head = ch->ch_r_head & rmask;
 561         tail = ch->ch_r_tail & rmask;
 562
 563         data_len = (head - tail) & rmask;
 564         if (data_len == 0) {
 565                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 566                 return;
 567         }
 568
 569         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
 570
 571         /*
 572          *If the device is not open, or CREAD is off, flush
 573          *input data and return immediately.
 574          */
 575         if (!tp ||
 576                 !(tp->termios.c_cflag & CREAD) ) {
 577
 578                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 579                         "input. dropping %d bytes on port %d...\n",
 580                         data_len, ch->ch_portnum);
 581                 ch->ch_r_head = tail;
 582
 583                 /* Force queue flow control to be released, if needed */
 584                 jsm_check_queue_flow_control(ch);
 585
 586                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 587                 return;
 588         }
 589
 590         /*
 591          * If we are throttled, simply don't read any data.
 592          */
 593         if (ch->ch_flags & CH_STOPI) {
 594                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 595                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 596                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 597                         ch->ch_portnum, head, tail);
 598                 return;
 599         }
 600
 601         jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");
 602
 603         len = tty_buffer_request_room(port, data_len);
 604         n = len;
 605
 606         /*
 607          * n now contains the most amount of data we can copy,
 608          * bounded either by the flip buffer size or the amount
 609          * of data the card actually has pending...
 610          */
 611         while (n) {
 612                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 613                 s = min(s, n);
 614
 615                 if (s <= 0)
 616                         break;
 617
 618                         /*
 619                          * If conditions are such that ld needs to see all
 620                          * UART errors, we will have to walk each character
 621                          * and error byte and send them to the buffer one at
 622                          * a time.
 623                          */
 624
 625                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 626                         for (i = 0; i < s; i++) {
 627                                 /*
 628                                  * Give the Linux ld the flags in the
 629                                  * format it likes.
 630                                  */
 631                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 632                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 633                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 634                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 635                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 636                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 637                                 else
 638                                         tty_insert_flip_char(port, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 639                         }
 640                 } else {
 641                         tty_insert_flip_string(port, ch->ch_rqueue + tail, s);
 642                 }
 643                 tail += s;
 644                 n -= s;
 645                 /* Flip queue if needed */
 646                 tail &= rmask;
 647         }
 648
 649         ch->ch_r_tail = tail & rmask;
 650         ch->ch_e_tail = tail & rmask;
 651         jsm_check_queue_flow_control(ch);
 652         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 653
 654         /* Tell the tty layer its okay to "eat" the data now */
 655         tty_flip_buffer_push(port);
 656
 657         jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
 658 }
 659
 660 static void jsm_carrier(struct jsm_channel *ch)
 661 {
 662         struct jsm_board *bd;
 663
 664         int virt_carrier = 0;
 665         int phys_carrier = 0;
 666
 667         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");
 668         if (!ch)
 669                 return;
 670
 671         bd = ch->ch_bd;
 672
 673         if (!bd)
 674                 return;
 675
 676         if (ch->ch_mistat & UART_MSR_DCD) {
 677                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "mistat: %x D_CD: %x\n",
 678                         ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 679                 phys_carrier = 1;
 680         }
 681
 682         if (ch->ch_c_cflag & CLOCAL)
 683                 virt_carrier = 1;
 684
 685         jsm_dbg(CARR, &ch->ch_bd->pci_dev, "DCD: physical: %d virt: %d\n",
 686                 phys_carrier, virt_carrier);
 687
 688         /*
 689          * Test for a VIRTUAL carrier transition to HIGH.
 690          */
 691         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 692
 693                 /*
 694                  * When carrier rises, wake any threads waiting
 695                  * for carrier in the open routine.
 696                  */
 697
 698                 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "carrier: virt DCD rose\n");
 699
 700                 if (waitqueue_active(&(ch->ch_flags_wait)))
 701                         wake_up_interruptible(&ch->ch_flags_wait);
 702         }
 703
 704         /*
 705          * Test for a PHYSICAL carrier transition to HIGH.
 706          */
 707         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 708
 709                 /*
 710                  * When carrier rises, wake any threads waiting
 711                  * for carrier in the open routine.
 712                  */
 713
 714                 jsm_dbg(CARR, &ch->ch_bd->pci_dev,
 715                         "carrier: physical DCD rose\n");
 716
 717                 if (waitqueue_active(&(ch->ch_flags_wait)))
 718                         wake_up_interruptible(&ch->ch_flags_wait);
 719         }
 720
 721         /*
 722          *  Test for a PHYSICAL transition to low, so long as we aren't
 723          *  currently ignoring physical transitions (which is what "virtual
 724          *  carrier" indicates).
 725          *
 726          *  The transition of the virtual carrier to low really doesn't
 727          *  matter... it really only means "ignore carrier state", not
 728          *  "make pretend that carrier is there".
 729          */
 730         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 731                         && (phys_carrier == 0)) {
 732                 /*
 733                  *      When carrier drops:
 734                  *
 735                  *      Drop carrier on all open units.
 736                  *
 737                  *      Flush queues, waking up any task waiting in the
 738                  *      line discipline.
 739                  *
 740                  *      Send a hangup to the control terminal.
 741                  *
 742                  *      Enable all select calls.
 743                  */
 744                 if (waitqueue_active(&(ch->ch_flags_wait)))
 745                         wake_up_interruptible(&ch->ch_flags_wait);
 746         }
 747
 748         /*
 749          *  Make sure that our cached values reflect the current reality.
 750          */
 751         if (virt_carrier == 1)
 752                 ch->ch_flags |= CH_FCAR;
 753         else
 754                 ch->ch_flags &= ~CH_FCAR;
 755
 756         if (phys_carrier == 1)
 757                 ch->ch_flags |= CH_CD;
 758         else
 759                 ch->ch_flags &= ~CH_CD;
 760 }
 761
 762
 763 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 764 {
 765         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 766         int qleft;
 767
 768         /* Store how much space we have left in the queue */
 769         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 770                 qleft += RQUEUEMASK + 1;
 771
 772         /*
 773          * Check to see if we should enforce flow control on our queue because
 774          * the ld (or user) isn't reading data out of our queue fast enuf.
 775          *
 776          * NOTE: This is done based on what the current flow control of the
 777          * port is set for.
 778          *
 779          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 780          *      This will cause the UART's FIFO to back up, and force
 781          *      the RTS signal to be dropped.
 782          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 783          *      the other side, in hopes it will stop sending data to us.
 784          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 785          *      that gets sent into us when the queue fills up.
 786          */
 787         if (qleft < 256) {
 788                 /* HWFLOW */
 789                 if (ch->ch_c_cflag & CRTSCTS) {
 790                         if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
 791                                 bd_ops->disable_receiver(ch);
 792                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 793                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 794                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts\n",
 795                                         qleft);
 796                         }
 797                 }
 798                 /* SWFLOW */
 799                 else if (ch->ch_c_iflag & IXOFF) {
 800                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 801                                 bd_ops->send_stop_character(ch);
 802                                 ch->ch_stops_sent++;
 803                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 804                                         "Sending stop char! Times sent: %x\n",
 805                                         ch->ch_stops_sent);
 806                         }
 807                 }
 808         }
 809
 810         /*
 811          * Check to see if we should unenforce flow control because
 812          * ld (or user) finally read enuf data out of our queue.
 813          *
 814          * NOTE: This is done based on what the current flow control of the
 815          * port is set for.
 816          *
 817          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 818          *      This will cause the UART's FIFO to raise RTS back up,
 819          *      which will allow the other side to start sending data again.
 820          * 2) SWFLOW (IXOFF) - Send a start character to
 821          *      the other side, so it will start sending data to us again.
 822          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 823          *      other side, we don't need to do anything now.
 824          */
 825         if (qleft > (RQUEUESIZE / 2)) {
 826                 /* HWFLOW */
 827                 if (ch->ch_c_cflag & CRTSCTS) {
 828                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 829                                 bd_ops->enable_receiver(ch);
 830                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 831                                 jsm_dbg(READ, &ch->ch_bd->pci_dev,
 832                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts\n",
 833                                         qleft);
 834                         }
 835                 }
 836                 /* SWFLOW */
 837                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 838                         ch->ch_stops_sent = 0;
 839                         bd_ops->send_start_character(ch);
 840                         jsm_dbg(READ, &ch->ch_bd->pci_dev,
 841                                 "Sending start char!\n");
 842                 }
 843         }
 844 }