drivers/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  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 * Temple Place - Suite 330, Boston,
  19  * MA  02111-1307, USA.
  20  *
  21  * Contact Information:
  22  * Scott H Kilau <Scott_Kilau@digi.com>
  23  * Ananda Venkatarman <mansarov@us.ibm.com>
  24  * Modifications:
  25  * 01/19/06:    changed jsm_input routine to use the dynamically allocated
  26  *              tty_buffer changes. Contributors: Scott Kilau and Ananda V.
  27  ***********************************************************************/
  28 #include <linux/tty.h>
  29 #include <linux/tty_flip.h>
  30 #include <linux/serial_reg.h>
  31 #include <linux/delay.h>        /* For udelay */
  32 #include <linux/pci.h>
  33
  34 #include "jsm.h"
  35
  36 static void jsm_carrier(struct jsm_channel *ch);
  37
  38 static inline int jsm_get_mstat(struct jsm_channel *ch)
  39 {
  40         unsigned char mstat;
  41         unsigned result;
  42
  43         jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "start\n");
  44
  45         mstat = (ch->ch_mostat | ch->ch_mistat);
  46
  47         result = 0;
  48
  49         if (mstat & UART_MCR_DTR)
  50                 result |= TIOCM_DTR;
  51         if (mstat & UART_MCR_RTS)
  52                 result |= TIOCM_RTS;
  53         if (mstat & UART_MSR_CTS)
  54                 result |= TIOCM_CTS;
  55         if (mstat & UART_MSR_DSR)
  56                 result |= TIOCM_DSR;
  57         if (mstat & UART_MSR_RI)
  58                 result |= TIOCM_RI;
  59         if (mstat & UART_MSR_DCD)
  60                 result |= TIOCM_CD;
  61
  62         jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
  63         return result;
  64 }
  65
  66 static unsigned int jsm_tty_tx_empty(struct uart_port *port)
  67 {
  68         return TIOCSER_TEMT;
  69 }
  70
  71 /*
  72  * Return modem signals to ld.
  73  */
  74 static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
  75 {
  76         int result;
  77         struct jsm_channel *channel = (struct jsm_channel *)port;
  78
  79         jsm_printk(IOCTL, INFO, &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_printk(IOCTL, INFO, &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 = (struct jsm_channel *)port;
  99
 100         jsm_printk(IOCTL, INFO, &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_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
 115         udelay(10);
 116 }
 117
 118 static void jsm_tty_start_tx(struct uart_port *port)
 119 {
 120         struct jsm_channel *channel = (struct jsm_channel *)port;
 121
 122         jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");
 123
 124         channel->ch_flags &= ~(CH_STOP);
 125         jsm_tty_write(port);
 126
 127         jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
 128 }
 129
 130 static void jsm_tty_stop_tx(struct uart_port *port)
 131 {
 132         struct jsm_channel *channel = (struct jsm_channel *)port;
 133
 134         jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");
 135
 136         channel->ch_flags |= (CH_STOP);
 137
 138         jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
 139 }
 140
 141 static void jsm_tty_send_xchar(struct uart_port *port, char ch)
 142 {
 143         unsigned long lock_flags;
 144         struct jsm_channel *channel = (struct jsm_channel *)port;
 145         struct ktermios *termios;
 146
 147         spin_lock_irqsave(&port->lock, lock_flags);
 148         termios = port->info->port.tty->termios;
 149         if (ch == termios->c_cc[VSTART])
 150                 channel->ch_bd->bd_ops->send_start_character(channel);
 151
 152         if (ch == termios->c_cc[VSTOP])
 153                 channel->ch_bd->bd_ops->send_stop_character(channel);
 154         spin_unlock_irqrestore(&port->lock, lock_flags);
 155 }
 156
 157 static void jsm_tty_stop_rx(struct uart_port *port)
 158 {
 159         struct jsm_channel *channel = (struct jsm_channel *)port;
 160
 161         channel->ch_bd->bd_ops->disable_receiver(channel);
 162 }
 163
 164 static void jsm_tty_enable_ms(struct uart_port *port)
 165 {
 166         /* Nothing needed */
 167 }
 168
 169 static void jsm_tty_break(struct uart_port *port, int break_state)
 170 {
 171         unsigned long lock_flags;
 172         struct jsm_channel *channel = (struct jsm_channel *)port;
 173
 174         spin_lock_irqsave(&port->lock, lock_flags);
 175         if (break_state == -1)
 176                 channel->ch_bd->bd_ops->send_break(channel);
 177         else
 178                 channel->ch_bd->bd_ops->clear_break(channel, 0);
 179
 180         spin_unlock_irqrestore(&port->lock, lock_flags);
 181 }
 182
 183 static int jsm_tty_open(struct uart_port *port)
 184 {
 185         struct jsm_board *brd;
 186         int rc = 0;
 187         struct jsm_channel *channel = (struct jsm_channel *)port;
 188         struct ktermios *termios;
 189
 190         /* Get board pointer from our array of majors we have allocated */
 191         brd = channel->ch_bd;
 192
 193         /*
 194          * Allocate channel buffers for read/write/error.
 195          * Set flag, so we don't get trounced on.
 196          */
 197         channel->ch_flags |= (CH_OPENING);
 198
 199         /* Drop locks, as malloc with GFP_KERNEL can sleep */
 200
 201         if (!channel->ch_rqueue) {
 202                 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
 203                 if (!channel->ch_rqueue) {
 204                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 205                                 "unable to allocate read queue buf");
 206                         return -ENOMEM;
 207                 }
 208         }
 209         if (!channel->ch_equeue) {
 210                 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
 211                 if (!channel->ch_equeue) {
 212                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 213                                 "unable to allocate error queue buf");
 214                         return -ENOMEM;
 215                 }
 216         }
 217         if (!channel->ch_wqueue) {
 218                 channel->ch_wqueue = kzalloc(WQUEUESIZE, GFP_KERNEL);
 219                 if (!channel->ch_wqueue) {
 220                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 221                                 "unable to allocate write queue buf");
 222                         return -ENOMEM;
 223                 }
 224         }
 225
 226         channel->ch_flags &= ~(CH_OPENING);
 227         /*
 228          * Initialize if neither terminal is open.
 229          */
 230         jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev,
 231                 "jsm_open: initializing channel in open...\n");
 232
 233         /*
 234          * Flush input queues.
 235          */
 236         channel->ch_r_head = channel->ch_r_tail = 0;
 237         channel->ch_e_head = channel->ch_e_tail = 0;
 238         channel->ch_w_head = channel->ch_w_tail = 0;
 239
 240         brd->bd_ops->flush_uart_write(channel);
 241         brd->bd_ops->flush_uart_read(channel);
 242
 243         channel->ch_flags = 0;
 244         channel->ch_cached_lsr = 0;
 245         channel->ch_stops_sent = 0;
 246
 247         termios = port->info->port.tty->termios;
 248         channel->ch_c_cflag     = termios->c_cflag;
 249         channel->ch_c_iflag     = termios->c_iflag;
 250         channel->ch_c_oflag     = termios->c_oflag;
 251         channel->ch_c_lflag     = termios->c_lflag;
 252         channel->ch_startc      = termios->c_cc[VSTART];
 253         channel->ch_stopc       = termios->c_cc[VSTOP];
 254
 255         /* Tell UART to init itself */
 256         brd->bd_ops->uart_init(channel);
 257
 258         /*
 259          * Run param in case we changed anything
 260          */
 261         brd->bd_ops->param(channel);
 262
 263         jsm_carrier(channel);
 264
 265         channel->ch_open_count++;
 266
 267         jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev, "finish\n");
 268         return rc;
 269 }
 270
 271 static void jsm_tty_close(struct uart_port *port)
 272 {
 273         struct jsm_board *bd;
 274         struct ktermios *ts;
 275         struct jsm_channel *channel = (struct jsm_channel *)port;
 276
 277         jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "start\n");
 278
 279         bd = channel->ch_bd;
 280         ts = port->info->port.tty->termios;
 281
 282         channel->ch_flags &= ~(CH_STOPI);
 283
 284         channel->ch_open_count--;
 285
 286         /*
 287          * If we have HUPCL set, lower DTR and RTS
 288          */
 289         if (channel->ch_c_cflag & HUPCL) {
 290                 jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev,
 291                         "Close. HUPCL set, dropping DTR/RTS\n");
 292
 293                 /* Drop RTS/DTR */
 294                 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
 295                 bd->bd_ops->assert_modem_signals(channel);
 296         }
 297
 298         channel->ch_old_baud = 0;
 299
 300         /* Turn off UART interrupts for this port */
 301         channel->ch_bd->bd_ops->uart_off(channel);
 302
 303         jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "finish\n");
 304 }
 305
 306 static void jsm_tty_set_termios(struct uart_port *port,
 307                                  struct ktermios *termios,
 308                                  struct ktermios *old_termios)
 309 {
 310         unsigned long lock_flags;
 311         struct jsm_channel *channel = (struct jsm_channel *)port;
 312
 313         spin_lock_irqsave(&port->lock, lock_flags);
 314         channel->ch_c_cflag     = termios->c_cflag;
 315         channel->ch_c_iflag     = termios->c_iflag;
 316         channel->ch_c_oflag     = termios->c_oflag;
 317         channel->ch_c_lflag     = termios->c_lflag;
 318         channel->ch_startc      = termios->c_cc[VSTART];
 319         channel->ch_stopc       = termios->c_cc[VSTOP];
 320
 321         channel->ch_bd->bd_ops->param(channel);
 322         jsm_carrier(channel);
 323         spin_unlock_irqrestore(&port->lock, lock_flags);
 324 }
 325
 326 static const char *jsm_tty_type(struct uart_port *port)
 327 {
 328         return "jsm";
 329 }
 330
 331 static void jsm_tty_release_port(struct uart_port *port)
 332 {
 333 }
 334
 335 static int jsm_tty_request_port(struct uart_port *port)
 336 {
 337         return 0;
 338 }
 339
 340 static void jsm_config_port(struct uart_port *port, int flags)
 341 {
 342         port->type = PORT_JSM;
 343 }
 344
 345 static struct uart_ops jsm_ops = {
 346         .tx_empty       = jsm_tty_tx_empty,
 347         .set_mctrl      = jsm_tty_set_mctrl,
 348         .get_mctrl      = jsm_tty_get_mctrl,
 349         .stop_tx        = jsm_tty_stop_tx,
 350         .start_tx       = jsm_tty_start_tx,
 351         .send_xchar     = jsm_tty_send_xchar,
 352         .stop_rx        = jsm_tty_stop_rx,
 353         .enable_ms      = jsm_tty_enable_ms,
 354         .break_ctl      = jsm_tty_break,
 355         .startup        = jsm_tty_open,
 356         .shutdown       = jsm_tty_close,
 357         .set_termios    = jsm_tty_set_termios,
 358         .type           = jsm_tty_type,
 359         .release_port   = jsm_tty_release_port,
 360         .request_port   = jsm_tty_request_port,
 361         .config_port    = jsm_config_port,
 362 };
 363
 364 /*
 365  * jsm_tty_init()
 366  *
 367  * Init the tty subsystem.  Called once per board after board has been
 368  * downloaded and init'ed.
 369  */
 370 int jsm_tty_init(struct jsm_board *brd)
 371 {
 372         int i;
 373         void __iomem *vaddr;
 374         struct jsm_channel *ch;
 375
 376         if (!brd)
 377                 return -ENXIO;
 378
 379         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 380
 381         /*
 382          * Initialize board structure elements.
 383          */
 384
 385         brd->nasync = brd->maxports;
 386
 387         /*
 388          * Allocate channel memory that might not have been allocated
 389          * when the driver was first loaded.
 390          */
 391         for (i = 0; i < brd->nasync; i++) {
 392                 if (!brd->channels[i]) {
 393
 394                         /*
 395                          * Okay to malloc with GFP_KERNEL, we are not at
 396                          * interrupt context, and there are no locks held.
 397                          */
 398                         brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
 399                         if (!brd->channels[i]) {
 400                                 jsm_printk(CORE, ERR, &brd->pci_dev,
 401                                         "%s:%d Unable to allocate memory for channel struct\n",
 402                                                          __FILE__, __LINE__);
 403                         }
 404                 }
 405         }
 406
 407         ch = brd->channels[0];
 408         vaddr = brd->re_map_membase;
 409
 410         /* Set up channel variables */
 411         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 412
 413                 if (!brd->channels[i])
 414                         continue;
 415
 416                 spin_lock_init(&ch->ch_lock);
 417
 418                 if (brd->bd_uart_offset == 0x200)
 419                         ch->ch_neo_uart =  vaddr + (brd->bd_uart_offset * i);
 420
 421                 ch->ch_bd = brd;
 422                 ch->ch_portnum = i;
 423
 424                 /* .25 second delay */
 425                 ch->ch_close_delay = 250;
 426
 427                 init_waitqueue_head(&ch->ch_flags_wait);
 428         }
 429
 430         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 431         return 0;
 432 }
 433
 434 int jsm_uart_port_init(struct jsm_board *brd)
 435 {
 436         int i;
 437         struct jsm_channel *ch;
 438
 439         if (!brd)
 440                 return -ENXIO;
 441
 442         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 443
 444         /*
 445          * Initialize board structure elements.
 446          */
 447
 448         brd->nasync = brd->maxports;
 449
 450         /* Set up channel variables */
 451         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 452
 453                 if (!brd->channels[i])
 454                         continue;
 455
 456                 brd->channels[i]->uart_port.irq = brd->irq;
 457                 brd->channels[i]->uart_port.uartclk = 14745600;
 458                 brd->channels[i]->uart_port.type = PORT_JSM;
 459                 brd->channels[i]->uart_port.iotype = UPIO_MEM;
 460                 brd->channels[i]->uart_port.membase = brd->re_map_membase;
 461                 brd->channels[i]->uart_port.fifosize = 16;
 462                 brd->channels[i]->uart_port.ops = &jsm_ops;
 463                 brd->channels[i]->uart_port.line = brd->channels[i]->ch_portnum + brd->boardnum * 2;
 464                 if (uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port))
 465                         printk(KERN_INFO "Added device failed\n");
 466                 else
 467                         printk(KERN_INFO "Added device \n");
 468         }
 469
 470         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 471         return 0;
 472 }
 473
 474 int jsm_remove_uart_port(struct jsm_board *brd)
 475 {
 476         int i;
 477         struct jsm_channel *ch;
 478
 479         if (!brd)
 480                 return -ENXIO;
 481
 482         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 483
 484         /*
 485          * Initialize board structure elements.
 486          */
 487
 488         brd->nasync = brd->maxports;
 489
 490         /* Set up channel variables */
 491         for (i = 0; i < brd->nasync; i++) {
 492
 493                 if (!brd->channels[i])
 494                         continue;
 495
 496                 ch = brd->channels[i];
 497
 498                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 499         }
 500
 501         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 502         return 0;
 503 }
 504
 505 void jsm_input(struct jsm_channel *ch)
 506 {
 507         struct jsm_board *bd;
 508         struct tty_struct *tp;
 509         u32 rmask;
 510         u16 head;
 511         u16 tail;
 512         int data_len;
 513         unsigned long lock_flags;
 514         int len = 0;
 515         int n = 0;
 516         int s = 0;
 517         int i = 0;
 518
 519         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 520
 521         if (!ch)
 522                 return;
 523
 524         tp = ch->uart_port.info->port.tty;
 525
 526         bd = ch->ch_bd;
 527         if(!bd)
 528                 return;
 529
 530         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 531
 532         /*
 533          *Figure the number of characters in the buffer.
 534          *Exit immediately if none.
 535          */
 536
 537         rmask = RQUEUEMASK;
 538
 539         head = ch->ch_r_head & rmask;
 540         tail = ch->ch_r_tail & rmask;
 541
 542         data_len = (head - tail) & rmask;
 543         if (data_len == 0) {
 544                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 545                 return;
 546         }
 547
 548         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 549
 550         /*
 551          *If the device is not open, or CREAD is off, flush
 552          *input data and return immediately.
 553          */
 554         if (!tp ||
 555                 !(tp->termios->c_cflag & CREAD) ) {
 556
 557                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 558                         "input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
 559                 ch->ch_r_head = tail;
 560
 561                 /* Force queue flow control to be released, if needed */
 562                 jsm_check_queue_flow_control(ch);
 563
 564                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 565                 return;
 566         }
 567
 568         /*
 569          * If we are throttled, simply don't read any data.
 570          */
 571         if (ch->ch_flags & CH_STOPI) {
 572                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 573                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 574                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 575                         ch->ch_portnum, head, tail);
 576                 return;
 577         }
 578
 579         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");
 580
 581         if (data_len <= 0) {
 582                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 583                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
 584                 return;
 585         }
 586
 587         len = tty_buffer_request_room(tp, data_len);
 588         n = len;
 589
 590         /*
 591          * n now contains the most amount of data we can copy,
 592          * bounded either by the flip buffer size or the amount
 593          * of data the card actually has pending...
 594          */
 595         while (n) {
 596                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 597                 s = min(s, n);
 598
 599                 if (s <= 0)
 600                         break;
 601
 602                         /*
 603                          * If conditions are such that ld needs to see all
 604                          * UART errors, we will have to walk each character
 605                          * and error byte and send them to the buffer one at
 606                          * a time.
 607                          */
 608
 609                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 610                         for (i = 0; i < s; i++) {
 611                                 /*
 612                                  * Give the Linux ld the flags in the
 613                                  * format it likes.
 614                                  */
 615                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 616                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 617                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 618                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 619                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 620                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 621                                 else
 622                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 623                         }
 624                 } else {
 625                         tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
 626                 }
 627                 tail += s;
 628                 n -= s;
 629                 /* Flip queue if needed */
 630                 tail &= rmask;
 631         }
 632
 633         ch->ch_r_tail = tail & rmask;
 634         ch->ch_e_tail = tail & rmask;
 635         jsm_check_queue_flow_control(ch);
 636         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 637
 638         /* Tell the tty layer its okay to "eat" the data now */
 639         tty_flip_buffer_push(tp);
 640
 641         jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
 642 }
 643
 644 static void jsm_carrier(struct jsm_channel *ch)
 645 {
 646         struct jsm_board *bd;
 647
 648         int virt_carrier = 0;
 649         int phys_carrier = 0;
 650
 651         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev, "start\n");
 652         if (!ch)
 653                 return;
 654
 655         bd = ch->ch_bd;
 656
 657         if (!bd)
 658                 return;
 659
 660         if (ch->ch_mistat & UART_MSR_DCD) {
 661                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 662                         "mistat: %x D_CD: %x\n", ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 663                 phys_carrier = 1;
 664         }
 665
 666         if (ch->ch_c_cflag & CLOCAL)
 667                 virt_carrier = 1;
 668
 669         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 670                 "DCD: physical: %d virt: %d\n", phys_carrier, virt_carrier);
 671
 672         /*
 673          * Test for a VIRTUAL carrier transition to HIGH.
 674          */
 675         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 676
 677                 /*
 678                  * When carrier rises, wake any threads waiting
 679                  * for carrier in the open routine.
 680                  */
 681
 682                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 683                         "carrier: virt DCD rose\n");
 684
 685                 if (waitqueue_active(&(ch->ch_flags_wait)))
 686                         wake_up_interruptible(&ch->ch_flags_wait);
 687         }
 688
 689         /*
 690          * Test for a PHYSICAL carrier transition to HIGH.
 691          */
 692         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 693
 694                 /*
 695                  * When carrier rises, wake any threads waiting
 696                  * for carrier in the open routine.
 697                  */
 698
 699                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 700                         "carrier: physical DCD rose\n");
 701
 702                 if (waitqueue_active(&(ch->ch_flags_wait)))
 703                         wake_up_interruptible(&ch->ch_flags_wait);
 704         }
 705
 706         /*
 707          *  Test for a PHYSICAL transition to low, so long as we aren't
 708          *  currently ignoring physical transitions (which is what "virtual
 709          *  carrier" indicates).
 710          *
 711          *  The transition of the virtual carrier to low really doesn't
 712          *  matter... it really only means "ignore carrier state", not
 713          *  "make pretend that carrier is there".
 714          */
 715         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 716                         && (phys_carrier == 0)) {
 717                 /*
 718                  *      When carrier drops:
 719                  *
 720                  *      Drop carrier on all open units.
 721                  *
 722                  *      Flush queues, waking up any task waiting in the
 723                  *      line discipline.
 724                  *
 725                  *      Send a hangup to the control terminal.
 726                  *
 727                  *      Enable all select calls.
 728                  */
 729                 if (waitqueue_active(&(ch->ch_flags_wait)))
 730                         wake_up_interruptible(&ch->ch_flags_wait);
 731         }
 732
 733         /*
 734          *  Make sure that our cached values reflect the current reality.
 735          */
 736         if (virt_carrier == 1)
 737                 ch->ch_flags |= CH_FCAR;
 738         else
 739                 ch->ch_flags &= ~CH_FCAR;
 740
 741         if (phys_carrier == 1)
 742                 ch->ch_flags |= CH_CD;
 743         else
 744                 ch->ch_flags &= ~CH_CD;
 745 }
 746
 747
 748 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 749 {
 750         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 751         int qleft = 0;
 752
 753         /* Store how much space we have left in the queue */
 754         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 755                 qleft += RQUEUEMASK + 1;
 756
 757         /*
 758          * Check to see if we should enforce flow control on our queue because
 759          * the ld (or user) isn't reading data out of our queue fast enuf.
 760          *
 761          * NOTE: This is done based on what the current flow control of the
 762          * port is set for.
 763          *
 764          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 765          *      This will cause the UART's FIFO to back up, and force
 766          *      the RTS signal to be dropped.
 767          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 768          *      the other side, in hopes it will stop sending data to us.
 769          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 770          *      that gets sent into us when the queue fills up.
 771          */
 772         if (qleft < 256) {
 773                 /* HWFLOW */
 774                 if (ch->ch_c_cflag & CRTSCTS) {
 775                         if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
 776                                 bd_ops->disable_receiver(ch);
 777                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 778                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 779                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
 780                                         qleft);
 781                         }
 782                 }
 783                 /* SWFLOW */
 784                 else if (ch->ch_c_iflag & IXOFF) {
 785                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 786                                 bd_ops->send_stop_character(ch);
 787                                 ch->ch_stops_sent++;
 788                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 789                                         "Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
 790                         }
 791                 }
 792         }
 793
 794         /*
 795          * Check to see if we should unenforce flow control because
 796          * ld (or user) finally read enuf data out of our queue.
 797          *
 798          * NOTE: This is done based on what the current flow control of the
 799          * port is set for.
 800          *
 801          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 802          *      This will cause the UART's FIFO to raise RTS back up,
 803          *      which will allow the other side to start sending data again.
 804          * 2) SWFLOW (IXOFF) - Send a start character to
 805          *      the other side, so it will start sending data to us again.
 806          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 807          *      other side, we don't need to do anything now.
 808          */
 809         if (qleft > (RQUEUESIZE / 2)) {
 810                 /* HWFLOW */
 811                 if (ch->ch_c_cflag & CRTSCTS) {
 812                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 813                                 bd_ops->enable_receiver(ch);
 814                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 815                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 816                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
 817                                         qleft);
 818                         }
 819                 }
 820                 /* SWFLOW */
 821                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 822                         ch->ch_stops_sent = 0;
 823                         bd_ops->send_start_character(ch);
 824                         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
 825                 }
 826         }
 827 }
 828
 829 /*
 830  * jsm_tty_write()
 831  *
 832  * Take data from the user or kernel and send it out to the FEP.
 833  * In here exists all the Transparent Print magic as well.
 834  */
 835 int jsm_tty_write(struct uart_port *port)
 836 {
 837         int bufcount = 0, n = 0;
 838         int data_count = 0,data_count1 =0;
 839         u16 head;
 840         u16 tail;
 841         u16 tmask;
 842         u32 remain;
 843         int temp_tail = port->info->xmit.tail;
 844         struct jsm_channel *channel = (struct jsm_channel *)port;
 845
 846         tmask = WQUEUEMASK;
 847         head = (channel->ch_w_head) & tmask;
 848         tail = (channel->ch_w_tail) & tmask;
 849
 850         if ((bufcount = tail - head - 1) < 0)
 851                 bufcount += WQUEUESIZE;
 852
 853         n = bufcount;
 854
 855         n = min(n, 56);
 856         remain = WQUEUESIZE - head;
 857
 858         data_count = 0;
 859         if (n >= remain) {
 860                 n -= remain;
 861                 while ((port->info->xmit.head != temp_tail) &&
 862                 (data_count < remain)) {
 863                         channel->ch_wqueue[head++] =
 864                         port->info->xmit.buf[temp_tail];
 865
 866                         temp_tail++;
 867                         temp_tail &= (UART_XMIT_SIZE - 1);
 868                         data_count++;
 869                 }
 870                 if (data_count == remain) head = 0;
 871         }
 872
 873         data_count1 = 0;
 874         if (n > 0) {
 875                 remain = n;
 876                 while ((port->info->xmit.head != temp_tail) &&
 877                         (data_count1 < remain)) {
 878                         channel->ch_wqueue[head++] =
 879                                 port->info->xmit.buf[temp_tail];
 880
 881                         temp_tail++;
 882                         temp_tail &= (UART_XMIT_SIZE - 1);
 883                         data_count1++;
 884
 885                 }
 886         }
 887
 888         port->info->xmit.tail = temp_tail;
 889
 890         data_count += data_count1;
 891         if (data_count) {
 892                 head &= tmask;
 893                 channel->ch_w_head = head;
 894         }
 895
 896         if (data_count) {
 897                 channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
 898         }
 899
 900         return data_count;
 901 }