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->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_break(struct uart_port *port, int break_state)
 165 {
 166         unsigned long lock_flags;
 167         struct jsm_channel *channel = (struct jsm_channel *)port;
 168
 169         spin_lock_irqsave(&port->lock, lock_flags);
 170         if (break_state == -1)
 171                 channel->ch_bd->bd_ops->send_break(channel);
 172         else
 173                 channel->ch_bd->bd_ops->clear_break(channel, 0);
 174
 175         spin_unlock_irqrestore(&port->lock, lock_flags);
 176 }
 177
 178 static int jsm_tty_open(struct uart_port *port)
 179 {
 180         struct jsm_board *brd;
 181         int rc = 0;
 182         struct jsm_channel *channel = (struct jsm_channel *)port;
 183         struct ktermios *termios;
 184
 185         /* Get board pointer from our array of majors we have allocated */
 186         brd = channel->ch_bd;
 187
 188         /*
 189          * Allocate channel buffers for read/write/error.
 190          * Set flag, so we don't get trounced on.
 191          */
 192         channel->ch_flags |= (CH_OPENING);
 193
 194         /* Drop locks, as malloc with GFP_KERNEL can sleep */
 195
 196         if (!channel->ch_rqueue) {
 197                 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
 198                 if (!channel->ch_rqueue) {
 199                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 200                                 "unable to allocate read queue buf");
 201                         return -ENOMEM;
 202                 }
 203         }
 204         if (!channel->ch_equeue) {
 205                 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
 206                 if (!channel->ch_equeue) {
 207                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 208                                 "unable to allocate error queue buf");
 209                         return -ENOMEM;
 210                 }
 211         }
 212         if (!channel->ch_wqueue) {
 213                 channel->ch_wqueue = kzalloc(WQUEUESIZE, GFP_KERNEL);
 214                 if (!channel->ch_wqueue) {
 215                         jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
 216                                 "unable to allocate write queue buf");
 217                         return -ENOMEM;
 218                 }
 219         }
 220
 221         channel->ch_flags &= ~(CH_OPENING);
 222         /*
 223          * Initialize if neither terminal is open.
 224          */
 225         jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev,
 226                 "jsm_open: initializing channel in open...\n");
 227
 228         /*
 229          * Flush input queues.
 230          */
 231         channel->ch_r_head = channel->ch_r_tail = 0;
 232         channel->ch_e_head = channel->ch_e_tail = 0;
 233         channel->ch_w_head = channel->ch_w_tail = 0;
 234
 235         brd->bd_ops->flush_uart_write(channel);
 236         brd->bd_ops->flush_uart_read(channel);
 237
 238         channel->ch_flags = 0;
 239         channel->ch_cached_lsr = 0;
 240         channel->ch_stops_sent = 0;
 241
 242         termios = port->info->tty->termios;
 243         channel->ch_c_cflag     = termios->c_cflag;
 244         channel->ch_c_iflag     = termios->c_iflag;
 245         channel->ch_c_oflag     = termios->c_oflag;
 246         channel->ch_c_lflag     = termios->c_lflag;
 247         channel->ch_startc      = termios->c_cc[VSTART];
 248         channel->ch_stopc       = termios->c_cc[VSTOP];
 249
 250         /* Tell UART to init itself */
 251         brd->bd_ops->uart_init(channel);
 252
 253         /*
 254          * Run param in case we changed anything
 255          */
 256         brd->bd_ops->param(channel);
 257
 258         jsm_carrier(channel);
 259
 260         channel->ch_open_count++;
 261
 262         jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev, "finish\n");
 263         return rc;
 264 }
 265
 266 static void jsm_tty_close(struct uart_port *port)
 267 {
 268         struct jsm_board *bd;
 269         struct ktermios *ts;
 270         struct jsm_channel *channel = (struct jsm_channel *)port;
 271
 272         jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "start\n");
 273
 274         bd = channel->ch_bd;
 275         ts = channel->uart_port.info->tty->termios;
 276
 277         channel->ch_flags &= ~(CH_STOPI);
 278
 279         channel->ch_open_count--;
 280
 281         /*
 282          * If we have HUPCL set, lower DTR and RTS
 283          */
 284         if (channel->ch_c_cflag & HUPCL) {
 285                 jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev,
 286                         "Close. HUPCL set, dropping DTR/RTS\n");
 287
 288                 /* Drop RTS/DTR */
 289                 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
 290                 bd->bd_ops->assert_modem_signals(channel);
 291         }
 292
 293         channel->ch_old_baud = 0;
 294
 295         /* Turn off UART interrupts for this port */
 296         channel->ch_bd->bd_ops->uart_off(channel);
 297
 298         jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "finish\n");
 299 }
 300
 301 static void jsm_tty_set_termios(struct uart_port *port,
 302                                  struct ktermios *termios,
 303                                  struct ktermios *old_termios)
 304 {
 305         unsigned long lock_flags;
 306         struct jsm_channel *channel = (struct jsm_channel *)port;
 307
 308         spin_lock_irqsave(&port->lock, lock_flags);
 309         channel->ch_c_cflag     = termios->c_cflag;
 310         channel->ch_c_iflag     = termios->c_iflag;
 311         channel->ch_c_oflag     = termios->c_oflag;
 312         channel->ch_c_lflag     = termios->c_lflag;
 313         channel->ch_startc      = termios->c_cc[VSTART];
 314         channel->ch_stopc       = termios->c_cc[VSTOP];
 315
 316         channel->ch_bd->bd_ops->param(channel);
 317         jsm_carrier(channel);
 318         spin_unlock_irqrestore(&port->lock, lock_flags);
 319 }
 320
 321 static const char *jsm_tty_type(struct uart_port *port)
 322 {
 323         return "jsm";
 324 }
 325
 326 static void jsm_tty_release_port(struct uart_port *port)
 327 {
 328 }
 329
 330 static int jsm_tty_request_port(struct uart_port *port)
 331 {
 332         return 0;
 333 }
 334
 335 static void jsm_config_port(struct uart_port *port, int flags)
 336 {
 337         port->type = PORT_JSM;
 338 }
 339
 340 static struct uart_ops jsm_ops = {
 341         .tx_empty       = jsm_tty_tx_empty,
 342         .set_mctrl      = jsm_tty_set_mctrl,
 343         .get_mctrl      = jsm_tty_get_mctrl,
 344         .stop_tx        = jsm_tty_stop_tx,
 345         .start_tx       = jsm_tty_start_tx,
 346         .send_xchar     = jsm_tty_send_xchar,
 347         .stop_rx        = jsm_tty_stop_rx,
 348         .break_ctl      = jsm_tty_break,
 349         .startup        = jsm_tty_open,
 350         .shutdown       = jsm_tty_close,
 351         .set_termios    = jsm_tty_set_termios,
 352         .type           = jsm_tty_type,
 353         .release_port   = jsm_tty_release_port,
 354         .request_port   = jsm_tty_request_port,
 355         .config_port    = jsm_config_port,
 356 };
 357
 358 /*
 359  * jsm_tty_init()
 360  *
 361  * Init the tty subsystem.  Called once per board after board has been
 362  * downloaded and init'ed.
 363  */
 364 int jsm_tty_init(struct jsm_board *brd)
 365 {
 366         int i;
 367         void __iomem *vaddr;
 368         struct jsm_channel *ch;
 369
 370         if (!brd)
 371                 return -ENXIO;
 372
 373         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 374
 375         /*
 376          * Initialize board structure elements.
 377          */
 378
 379         brd->nasync = brd->maxports;
 380
 381         /*
 382          * Allocate channel memory that might not have been allocated
 383          * when the driver was first loaded.
 384          */
 385         for (i = 0; i < brd->nasync; i++) {
 386                 if (!brd->channels[i]) {
 387
 388                         /*
 389                          * Okay to malloc with GFP_KERNEL, we are not at
 390                          * interrupt context, and there are no locks held.
 391                          */
 392                         brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
 393                         if (!brd->channels[i]) {
 394                                 jsm_printk(CORE, ERR, &brd->pci_dev,
 395                                         "%s:%d Unable to allocate memory for channel struct\n",
 396                                                          __FILE__, __LINE__);
 397                         }
 398                 }
 399         }
 400
 401         ch = brd->channels[0];
 402         vaddr = brd->re_map_membase;
 403
 404         /* Set up channel variables */
 405         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 406
 407                 if (!brd->channels[i])
 408                         continue;
 409
 410                 spin_lock_init(&ch->ch_lock);
 411
 412                 if (brd->bd_uart_offset == 0x200)
 413                         ch->ch_neo_uart =  vaddr + (brd->bd_uart_offset * i);
 414
 415                 ch->ch_bd = brd;
 416                 ch->ch_portnum = i;
 417
 418                 /* .25 second delay */
 419                 ch->ch_close_delay = 250;
 420
 421                 init_waitqueue_head(&ch->ch_flags_wait);
 422         }
 423
 424         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 425         return 0;
 426 }
 427
 428 int jsm_uart_port_init(struct jsm_board *brd)
 429 {
 430         int i;
 431         struct jsm_channel *ch;
 432
 433         if (!brd)
 434                 return -ENXIO;
 435
 436         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 437
 438         /*
 439          * Initialize board structure elements.
 440          */
 441
 442         brd->nasync = brd->maxports;
 443
 444         /* Set up channel variables */
 445         for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
 446
 447                 if (!brd->channels[i])
 448                         continue;
 449
 450                 brd->channels[i]->uart_port.irq = brd->irq;
 451                 brd->channels[i]->uart_port.type = PORT_JSM;
 452                 brd->channels[i]->uart_port.iotype = UPIO_MEM;
 453                 brd->channels[i]->uart_port.membase = brd->re_map_membase;
 454                 brd->channels[i]->uart_port.fifosize = 16;
 455                 brd->channels[i]->uart_port.ops = &jsm_ops;
 456                 brd->channels[i]->uart_port.line = brd->channels[i]->ch_portnum + brd->boardnum * 2;
 457                 if (uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port))
 458                         printk(KERN_INFO "Added device failed\n");
 459                 else
 460                         printk(KERN_INFO "Added device \n");
 461         }
 462
 463         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 464         return 0;
 465 }
 466
 467 int jsm_remove_uart_port(struct jsm_board *brd)
 468 {
 469         int i;
 470         struct jsm_channel *ch;
 471
 472         if (!brd)
 473                 return -ENXIO;
 474
 475         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 476
 477         /*
 478          * Initialize board structure elements.
 479          */
 480
 481         brd->nasync = brd->maxports;
 482
 483         /* Set up channel variables */
 484         for (i = 0; i < brd->nasync; i++) {
 485
 486                 if (!brd->channels[i])
 487                         continue;
 488
 489                 ch = brd->channels[i];
 490
 491                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 492         }
 493
 494         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 495         return 0;
 496 }
 497
 498 void jsm_input(struct jsm_channel *ch)
 499 {
 500         struct jsm_board *bd;
 501         struct tty_struct *tp;
 502         struct tty_ldisc *ld;
 503         u32 rmask;
 504         u16 head;
 505         u16 tail;
 506         int data_len;
 507         unsigned long lock_flags;
 508         int flip_len = 0;
 509         int len = 0;
 510         int n = 0;
 511         int s = 0;
 512         int i = 0;
 513
 514         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 515
 516         if (!ch)
 517                 return;
 518
 519         tp = ch->uart_port.info->tty;
 520
 521         bd = ch->ch_bd;
 522         if(!bd)
 523                 return;
 524
 525         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 526
 527         /*
 528          *Figure the number of characters in the buffer.
 529          *Exit immediately if none.
 530          */
 531
 532         rmask = RQUEUEMASK;
 533
 534         head = ch->ch_r_head & rmask;
 535         tail = ch->ch_r_tail & rmask;
 536
 537         data_len = (head - tail) & rmask;
 538         if (data_len == 0) {
 539                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 540                 return;
 541         }
 542
 543         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 544
 545         /*
 546          *If the device is not open, or CREAD is off, flush
 547          *input data and return immediately.
 548          */
 549         if (!tp ||
 550                 !(tp->termios->c_cflag & CREAD) ) {
 551
 552                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 553                         "input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
 554                 ch->ch_r_head = tail;
 555
 556                 /* Force queue flow control to be released, if needed */
 557                 jsm_check_queue_flow_control(ch);
 558
 559                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 560                 return;
 561         }
 562
 563         /*
 564          * If we are throttled, simply don't read any data.
 565          */
 566         if (ch->ch_flags & CH_STOPI) {
 567                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 568                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 569                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 570                         ch->ch_portnum, head, tail);
 571                 return;
 572         }
 573
 574         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");
 575
 576         /*
 577          * If the rxbuf is empty and we are not throttled, put as much
 578          * as we can directly into the linux TTY buffer.
 579          *
 580          */
 581         flip_len = TTY_FLIPBUF_SIZE;
 582
 583         len = min(data_len, flip_len);
 584         len = min(len, (N_TTY_BUF_SIZE - 1) - tp->read_cnt);
 585         ld = tty_ldisc_ref(tp);
 586
 587         /*
 588          * If we were unable to get a reference to the ld,
 589          * don't flush our buffer, and act like the ld doesn't
 590          * have any space to put the data right now.
 591          */
 592         if (!ld) {
 593                 len = 0;
 594         } else {
 595                 /*
 596                  * If ld doesn't have a pointer to a receive_buf function,
 597                  * flush the data, then act like the ld doesn't have any
 598                  * space to put the data right now.
 599                  */
 600                 if (!ld->receive_buf) {
 601                                 ch->ch_r_head = ch->ch_r_tail;
 602                                 len = 0;
 603                 }
 604         }
 605
 606         if (len <= 0) {
 607                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 608                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
 609                 if (ld)
 610                         tty_ldisc_deref(ld);
 611                 return;
 612         }
 613
 614         len = tty_buffer_request_room(tp, len);
 615         n = len;
 616
 617         /*
 618          * n now contains the most amount of data we can copy,
 619          * bounded either by the flip buffer size or the amount
 620          * of data the card actually has pending...
 621          */
 622         while (n) {
 623                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 624                 s = min(s, n);
 625
 626                 if (s <= 0)
 627                         break;
 628
 629                         /*
 630                          * If conditions are such that ld needs to see all
 631                          * UART errors, we will have to walk each character
 632                          * and error byte and send them to the buffer one at
 633                          * a time.
 634                          */
 635
 636                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 637                         for (i = 0; i < s; i++) {
 638                                 /*
 639                                  * Give the Linux ld the flags in the
 640                                  * format it likes.
 641                                  */
 642                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 643                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 644                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 645                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 646                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 647                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 648                                 else
 649                                 tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 650                         }
 651                 } else {
 652                         tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
 653                 }
 654                 tail += s;
 655                 n -= s;
 656                 /* Flip queue if needed */
 657                 tail &= rmask;
 658         }
 659
 660         ch->ch_r_tail = tail & rmask;
 661         ch->ch_e_tail = tail & rmask;
 662         jsm_check_queue_flow_control(ch);
 663         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 664
 665         /* Tell the tty layer its okay to "eat" the data now */
 666         tty_flip_buffer_push(tp);
 667
 668         if (ld)
 669                 tty_ldisc_deref(ld);
 670
 671         jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
 672 }
 673
 674 static void jsm_carrier(struct jsm_channel *ch)
 675 {
 676         struct jsm_board *bd;
 677
 678         int virt_carrier = 0;
 679         int phys_carrier = 0;
 680
 681         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev, "start\n");
 682         if (!ch)
 683                 return;
 684
 685         bd = ch->ch_bd;
 686
 687         if (!bd)
 688                 return;
 689
 690         if (ch->ch_mistat & UART_MSR_DCD) {
 691                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 692                         "mistat: %x D_CD: %x\n", ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 693                 phys_carrier = 1;
 694         }
 695
 696         if (ch->ch_c_cflag & CLOCAL)
 697                 virt_carrier = 1;
 698
 699         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 700                 "DCD: physical: %d virt: %d\n", phys_carrier, virt_carrier);
 701
 702         /*
 703          * Test for a VIRTUAL carrier transition to HIGH.
 704          */
 705         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 706
 707                 /*
 708                  * When carrier rises, wake any threads waiting
 709                  * for carrier in the open routine.
 710                  */
 711
 712                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 713                         "carrier: virt DCD rose\n");
 714
 715                 if (waitqueue_active(&(ch->ch_flags_wait)))
 716                         wake_up_interruptible(&ch->ch_flags_wait);
 717         }
 718
 719         /*
 720          * Test for a PHYSICAL carrier transition to HIGH.
 721          */
 722         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 723
 724                 /*
 725                  * When carrier rises, wake any threads waiting
 726                  * for carrier in the open routine.
 727                  */
 728
 729                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 730                         "carrier: physical DCD rose\n");
 731
 732                 if (waitqueue_active(&(ch->ch_flags_wait)))
 733                         wake_up_interruptible(&ch->ch_flags_wait);
 734         }
 735
 736         /*
 737          *  Test for a PHYSICAL transition to low, so long as we aren't
 738          *  currently ignoring physical transitions (which is what "virtual
 739          *  carrier" indicates).
 740          *
 741          *  The transition of the virtual carrier to low really doesn't
 742          *  matter... it really only means "ignore carrier state", not
 743          *  "make pretend that carrier is there".
 744          */
 745         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 746                         && (phys_carrier == 0)) {
 747                 /*
 748                  *      When carrier drops:
 749                  *
 750                  *      Drop carrier on all open units.
 751                  *
 752                  *      Flush queues, waking up any task waiting in the
 753                  *      line discipline.
 754                  *
 755                  *      Send a hangup to the control terminal.
 756                  *
 757                  *      Enable all select calls.
 758                  */
 759                 if (waitqueue_active(&(ch->ch_flags_wait)))
 760                         wake_up_interruptible(&ch->ch_flags_wait);
 761         }
 762
 763         /*
 764          *  Make sure that our cached values reflect the current reality.
 765          */
 766         if (virt_carrier == 1)
 767                 ch->ch_flags |= CH_FCAR;
 768         else
 769                 ch->ch_flags &= ~CH_FCAR;
 770
 771         if (phys_carrier == 1)
 772                 ch->ch_flags |= CH_CD;
 773         else
 774                 ch->ch_flags &= ~CH_CD;
 775 }
 776
 777
 778 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 779 {
 780         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 781         int qleft = 0;
 782
 783         /* Store how much space we have left in the queue */
 784         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 785                 qleft += RQUEUEMASK + 1;
 786
 787         /*
 788          * Check to see if we should enforce flow control on our queue because
 789          * the ld (or user) isn't reading data out of our queue fast enuf.
 790          *
 791          * NOTE: This is done based on what the current flow control of the
 792          * port is set for.
 793          *
 794          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 795          *      This will cause the UART's FIFO to back up, and force
 796          *      the RTS signal to be dropped.
 797          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 798          *      the other side, in hopes it will stop sending data to us.
 799          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 800          *      that gets sent into us when the queue fills up.
 801          */
 802         if (qleft < 256) {
 803                 /* HWFLOW */
 804                 if (ch->ch_c_cflag & CRTSCTS) {
 805                         if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
 806                                 bd_ops->disable_receiver(ch);
 807                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 808                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 809                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
 810                                         qleft);
 811                         }
 812                 }
 813                 /* SWFLOW */
 814                 else if (ch->ch_c_iflag & IXOFF) {
 815                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 816                                 bd_ops->send_stop_character(ch);
 817                                 ch->ch_stops_sent++;
 818                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 819                                         "Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
 820                         }
 821                 }
 822         }
 823
 824         /*
 825          * Check to see if we should unenforce flow control because
 826          * ld (or user) finally read enuf data out of our queue.
 827          *
 828          * NOTE: This is done based on what the current flow control of the
 829          * port is set for.
 830          *
 831          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 832          *      This will cause the UART's FIFO to raise RTS back up,
 833          *      which will allow the other side to start sending data again.
 834          * 2) SWFLOW (IXOFF) - Send a start character to
 835          *      the other side, so it will start sending data to us again.
 836          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 837          *      other side, we don't need to do anything now.
 838          */
 839         if (qleft > (RQUEUESIZE / 2)) {
 840                 /* HWFLOW */
 841                 if (ch->ch_c_cflag & CRTSCTS) {
 842                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 843                                 bd_ops->enable_receiver(ch);
 844                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 845                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 846                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
 847                                         qleft);
 848                         }
 849                 }
 850                 /* SWFLOW */
 851                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 852                         ch->ch_stops_sent = 0;
 853                         bd_ops->send_start_character(ch);
 854                         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
 855                 }
 856         }
 857 }
 858
 859 /*
 860  * jsm_tty_write()
 861  *
 862  * Take data from the user or kernel and send it out to the FEP.
 863  * In here exists all the Transparent Print magic as well.
 864  */
 865 int jsm_tty_write(struct uart_port *port)
 866 {
 867         int bufcount = 0, n = 0;
 868         int data_count = 0,data_count1 =0;
 869         u16 head;
 870         u16 tail;
 871         u16 tmask;
 872         u32 remain;
 873         int temp_tail = port->info->xmit.tail;
 874         struct jsm_channel *channel = (struct jsm_channel *)port;
 875
 876         tmask = WQUEUEMASK;
 877         head = (channel->ch_w_head) & tmask;
 878         tail = (channel->ch_w_tail) & tmask;
 879
 880         if ((bufcount = tail - head - 1) < 0)
 881                 bufcount += WQUEUESIZE;
 882
 883         n = bufcount;
 884
 885         n = min(n, 56);
 886         remain = WQUEUESIZE - head;
 887
 888         data_count = 0;
 889         if (n >= remain) {
 890                 n -= remain;
 891                 while ((port->info->xmit.head != temp_tail) &&
 892                 (data_count < remain)) {
 893                         channel->ch_wqueue[head++] =
 894                         port->info->xmit.buf[temp_tail];
 895
 896                         temp_tail++;
 897                         temp_tail &= (UART_XMIT_SIZE - 1);
 898                         data_count++;
 899                 }
 900                 if (data_count == remain) head = 0;
 901         }
 902
 903         data_count1 = 0;
 904         if (n > 0) {
 905                 remain = n;
 906                 while ((port->info->xmit.head != temp_tail) &&
 907                         (data_count1 < remain)) {
 908                         channel->ch_wqueue[head++] =
 909                                 port->info->xmit.buf[temp_tail];
 910
 911                         temp_tail++;
 912                         temp_tail &= (UART_XMIT_SIZE - 1);
 913                         data_count1++;
 914
 915                 }
 916         }
 917
 918         port->info->xmit.tail = temp_tail;
 919
 920         data_count += data_count1;
 921         if (data_count) {
 922                 head &= tmask;
 923                 channel->ch_w_head = head;
 924         }
 925
 926         if (data_count) {
 927                 channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
 928         }
 929
 930         return data_count;
 931 }