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.uartclk = 14745600;
 452                 brd->channels[i]->uart_port.type = PORT_JSM;
 453                 brd->channels[i]->uart_port.iotype = UPIO_MEM;
 454                 brd->channels[i]->uart_port.membase = brd->re_map_membase;
 455                 brd->channels[i]->uart_port.fifosize = 16;
 456                 brd->channels[i]->uart_port.ops = &jsm_ops;
 457                 brd->channels[i]->uart_port.line = brd->channels[i]->ch_portnum + brd->boardnum * 2;
 458                 if (uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port))
 459                         printk(KERN_INFO "Added device failed\n");
 460                 else
 461                         printk(KERN_INFO "Added device \n");
 462         }
 463
 464         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 465         return 0;
 466 }
 467
 468 int jsm_remove_uart_port(struct jsm_board *brd)
 469 {
 470         int i;
 471         struct jsm_channel *ch;
 472
 473         if (!brd)
 474                 return -ENXIO;
 475
 476         jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");
 477
 478         /*
 479          * Initialize board structure elements.
 480          */
 481
 482         brd->nasync = brd->maxports;
 483
 484         /* Set up channel variables */
 485         for (i = 0; i < brd->nasync; i++) {
 486
 487                 if (!brd->channels[i])
 488                         continue;
 489
 490                 ch = brd->channels[i];
 491
 492                 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
 493         }
 494
 495         jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
 496         return 0;
 497 }
 498
 499 void jsm_input(struct jsm_channel *ch)
 500 {
 501         struct jsm_board *bd;
 502         struct tty_struct *tp;
 503         struct tty_ldisc *ld;
 504         u32 rmask;
 505         u16 head;
 506         u16 tail;
 507         int data_len;
 508         unsigned long lock_flags;
 509         int flip_len = 0;
 510         int len = 0;
 511         int n = 0;
 512         int s = 0;
 513         int i = 0;
 514
 515         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 516
 517         if (!ch)
 518                 return;
 519
 520         tp = ch->uart_port.info->tty;
 521
 522         bd = ch->ch_bd;
 523         if(!bd)
 524                 return;
 525
 526         spin_lock_irqsave(&ch->ch_lock, lock_flags);
 527
 528         /*
 529          *Figure the number of characters in the buffer.
 530          *Exit immediately if none.
 531          */
 532
 533         rmask = RQUEUEMASK;
 534
 535         head = ch->ch_r_head & rmask;
 536         tail = ch->ch_r_tail & rmask;
 537
 538         data_len = (head - tail) & rmask;
 539         if (data_len == 0) {
 540                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 541                 return;
 542         }
 543
 544         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");
 545
 546         /*
 547          *If the device is not open, or CREAD is off, flush
 548          *input data and return immediately.
 549          */
 550         if (!tp ||
 551                 !(tp->termios->c_cflag & CREAD) ) {
 552
 553                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 554                         "input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
 555                 ch->ch_r_head = tail;
 556
 557                 /* Force queue flow control to be released, if needed */
 558                 jsm_check_queue_flow_control(ch);
 559
 560                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 561                 return;
 562         }
 563
 564         /*
 565          * If we are throttled, simply don't read any data.
 566          */
 567         if (ch->ch_flags & CH_STOPI) {
 568                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 569                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 570                         "Port %d throttled, not reading any data. head: %x tail: %x\n",
 571                         ch->ch_portnum, head, tail);
 572                 return;
 573         }
 574
 575         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");
 576
 577         /*
 578          * If the rxbuf is empty and we are not throttled, put as much
 579          * as we can directly into the linux TTY buffer.
 580          *
 581          */
 582         flip_len = TTY_FLIPBUF_SIZE;
 583
 584         len = min(data_len, flip_len);
 585         len = min(len, (N_TTY_BUF_SIZE - 1) - tp->read_cnt);
 586         ld = tty_ldisc_ref(tp);
 587
 588         /*
 589          * If we were unable to get a reference to the ld,
 590          * don't flush our buffer, and act like the ld doesn't
 591          * have any space to put the data right now.
 592          */
 593         if (!ld) {
 594                 len = 0;
 595         } else {
 596                 /*
 597                  * If ld doesn't have a pointer to a receive_buf function,
 598                  * flush the data, then act like the ld doesn't have any
 599                  * space to put the data right now.
 600                  */
 601                 if (!ld->receive_buf) {
 602                                 ch->ch_r_head = ch->ch_r_tail;
 603                                 len = 0;
 604                 }
 605         }
 606
 607         if (len <= 0) {
 608                 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 609                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
 610                 if (ld)
 611                         tty_ldisc_deref(ld);
 612                 return;
 613         }
 614
 615         len = tty_buffer_request_room(tp, len);
 616         n = len;
 617
 618         /*
 619          * n now contains the most amount of data we can copy,
 620          * bounded either by the flip buffer size or the amount
 621          * of data the card actually has pending...
 622          */
 623         while (n) {
 624                 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
 625                 s = min(s, n);
 626
 627                 if (s <= 0)
 628                         break;
 629
 630                         /*
 631                          * If conditions are such that ld needs to see all
 632                          * UART errors, we will have to walk each character
 633                          * and error byte and send them to the buffer one at
 634                          * a time.
 635                          */
 636
 637                 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
 638                         for (i = 0; i < s; i++) {
 639                                 /*
 640                                  * Give the Linux ld the flags in the
 641                                  * format it likes.
 642                                  */
 643                                 if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
 644                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
 645                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
 646                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
 647                                 else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
 648                                         tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
 649                                 else
 650                                 tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
 651                         }
 652                 } else {
 653                         tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
 654                 }
 655                 tail += s;
 656                 n -= s;
 657                 /* Flip queue if needed */
 658                 tail &= rmask;
 659         }
 660
 661         ch->ch_r_tail = tail & rmask;
 662         ch->ch_e_tail = tail & rmask;
 663         jsm_check_queue_flow_control(ch);
 664         spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
 665
 666         /* Tell the tty layer its okay to "eat" the data now */
 667         tty_flip_buffer_push(tp);
 668
 669         if (ld)
 670                 tty_ldisc_deref(ld);
 671
 672         jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
 673 }
 674
 675 static void jsm_carrier(struct jsm_channel *ch)
 676 {
 677         struct jsm_board *bd;
 678
 679         int virt_carrier = 0;
 680         int phys_carrier = 0;
 681
 682         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev, "start\n");
 683         if (!ch)
 684                 return;
 685
 686         bd = ch->ch_bd;
 687
 688         if (!bd)
 689                 return;
 690
 691         if (ch->ch_mistat & UART_MSR_DCD) {
 692                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 693                         "mistat: %x D_CD: %x\n", ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
 694                 phys_carrier = 1;
 695         }
 696
 697         if (ch->ch_c_cflag & CLOCAL)
 698                 virt_carrier = 1;
 699
 700         jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 701                 "DCD: physical: %d virt: %d\n", phys_carrier, virt_carrier);
 702
 703         /*
 704          * Test for a VIRTUAL carrier transition to HIGH.
 705          */
 706         if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
 707
 708                 /*
 709                  * When carrier rises, wake any threads waiting
 710                  * for carrier in the open routine.
 711                  */
 712
 713                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 714                         "carrier: virt DCD rose\n");
 715
 716                 if (waitqueue_active(&(ch->ch_flags_wait)))
 717                         wake_up_interruptible(&ch->ch_flags_wait);
 718         }
 719
 720         /*
 721          * Test for a PHYSICAL carrier transition to HIGH.
 722          */
 723         if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
 724
 725                 /*
 726                  * When carrier rises, wake any threads waiting
 727                  * for carrier in the open routine.
 728                  */
 729
 730                 jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
 731                         "carrier: physical DCD rose\n");
 732
 733                 if (waitqueue_active(&(ch->ch_flags_wait)))
 734                         wake_up_interruptible(&ch->ch_flags_wait);
 735         }
 736
 737         /*
 738          *  Test for a PHYSICAL transition to low, so long as we aren't
 739          *  currently ignoring physical transitions (which is what "virtual
 740          *  carrier" indicates).
 741          *
 742          *  The transition of the virtual carrier to low really doesn't
 743          *  matter... it really only means "ignore carrier state", not
 744          *  "make pretend that carrier is there".
 745          */
 746         if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
 747                         && (phys_carrier == 0)) {
 748                 /*
 749                  *      When carrier drops:
 750                  *
 751                  *      Drop carrier on all open units.
 752                  *
 753                  *      Flush queues, waking up any task waiting in the
 754                  *      line discipline.
 755                  *
 756                  *      Send a hangup to the control terminal.
 757                  *
 758                  *      Enable all select calls.
 759                  */
 760                 if (waitqueue_active(&(ch->ch_flags_wait)))
 761                         wake_up_interruptible(&ch->ch_flags_wait);
 762         }
 763
 764         /*
 765          *  Make sure that our cached values reflect the current reality.
 766          */
 767         if (virt_carrier == 1)
 768                 ch->ch_flags |= CH_FCAR;
 769         else
 770                 ch->ch_flags &= ~CH_FCAR;
 771
 772         if (phys_carrier == 1)
 773                 ch->ch_flags |= CH_CD;
 774         else
 775                 ch->ch_flags &= ~CH_CD;
 776 }
 777
 778
 779 void jsm_check_queue_flow_control(struct jsm_channel *ch)
 780 {
 781         struct board_ops *bd_ops = ch->ch_bd->bd_ops;
 782         int qleft = 0;
 783
 784         /* Store how much space we have left in the queue */
 785         if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
 786                 qleft += RQUEUEMASK + 1;
 787
 788         /*
 789          * Check to see if we should enforce flow control on our queue because
 790          * the ld (or user) isn't reading data out of our queue fast enuf.
 791          *
 792          * NOTE: This is done based on what the current flow control of the
 793          * port is set for.
 794          *
 795          * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
 796          *      This will cause the UART's FIFO to back up, and force
 797          *      the RTS signal to be dropped.
 798          * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
 799          *      the other side, in hopes it will stop sending data to us.
 800          * 3) NONE - Nothing we can do.  We will simply drop any extra data
 801          *      that gets sent into us when the queue fills up.
 802          */
 803         if (qleft < 256) {
 804                 /* HWFLOW */
 805                 if (ch->ch_c_cflag & CRTSCTS) {
 806                         if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
 807                                 bd_ops->disable_receiver(ch);
 808                                 ch->ch_flags |= (CH_RECEIVER_OFF);
 809                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 810                                         "Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
 811                                         qleft);
 812                         }
 813                 }
 814                 /* SWFLOW */
 815                 else if (ch->ch_c_iflag & IXOFF) {
 816                         if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
 817                                 bd_ops->send_stop_character(ch);
 818                                 ch->ch_stops_sent++;
 819                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 820                                         "Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
 821                         }
 822                 }
 823         }
 824
 825         /*
 826          * Check to see if we should unenforce flow control because
 827          * ld (or user) finally read enuf data out of our queue.
 828          *
 829          * NOTE: This is done based on what the current flow control of the
 830          * port is set for.
 831          *
 832          * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
 833          *      This will cause the UART's FIFO to raise RTS back up,
 834          *      which will allow the other side to start sending data again.
 835          * 2) SWFLOW (IXOFF) - Send a start character to
 836          *      the other side, so it will start sending data to us again.
 837          * 3) NONE - Do nothing. Since we didn't do anything to turn off the
 838          *      other side, we don't need to do anything now.
 839          */
 840         if (qleft > (RQUEUESIZE / 2)) {
 841                 /* HWFLOW */
 842                 if (ch->ch_c_cflag & CRTSCTS) {
 843                         if (ch->ch_flags & CH_RECEIVER_OFF) {
 844                                 bd_ops->enable_receiver(ch);
 845                                 ch->ch_flags &= ~(CH_RECEIVER_OFF);
 846                                 jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
 847                                         "Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
 848                                         qleft);
 849                         }
 850                 }
 851                 /* SWFLOW */
 852                 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
 853                         ch->ch_stops_sent = 0;
 854                         bd_ops->send_start_character(ch);
 855                         jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
 856                 }
 857         }
 858 }
 859
 860 /*
 861  * jsm_tty_write()
 862  *
 863  * Take data from the user or kernel and send it out to the FEP.
 864  * In here exists all the Transparent Print magic as well.
 865  */
 866 int jsm_tty_write(struct uart_port *port)
 867 {
 868         int bufcount = 0, n = 0;
 869         int data_count = 0,data_count1 =0;
 870         u16 head;
 871         u16 tail;
 872         u16 tmask;
 873         u32 remain;
 874         int temp_tail = port->info->xmit.tail;
 875         struct jsm_channel *channel = (struct jsm_channel *)port;
 876
 877         tmask = WQUEUEMASK;
 878         head = (channel->ch_w_head) & tmask;
 879         tail = (channel->ch_w_tail) & tmask;
 880
 881         if ((bufcount = tail - head - 1) < 0)
 882                 bufcount += WQUEUESIZE;
 883
 884         n = bufcount;
 885
 886         n = min(n, 56);
 887         remain = WQUEUESIZE - head;
 888
 889         data_count = 0;
 890         if (n >= remain) {
 891                 n -= remain;
 892                 while ((port->info->xmit.head != temp_tail) &&
 893                 (data_count < remain)) {
 894                         channel->ch_wqueue[head++] =
 895                         port->info->xmit.buf[temp_tail];
 896
 897                         temp_tail++;
 898                         temp_tail &= (UART_XMIT_SIZE - 1);
 899                         data_count++;
 900                 }
 901                 if (data_count == remain) head = 0;
 902         }
 903
 904         data_count1 = 0;
 905         if (n > 0) {
 906                 remain = n;
 907                 while ((port->info->xmit.head != temp_tail) &&
 908                         (data_count1 < remain)) {
 909                         channel->ch_wqueue[head++] =
 910                                 port->info->xmit.buf[temp_tail];
 911
 912                         temp_tail++;
 913                         temp_tail &= (UART_XMIT_SIZE - 1);
 914                         data_count1++;
 915
 916                 }
 917         }
 918
 919         port->info->xmit.tail = temp_tail;
 920
 921         data_count += data_count1;
 922         if (data_count) {
 923                 head &= tmask;
 924                 channel->ch_w_head = head;
 925         }
 926
 927         if (data_count) {
 928                 channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
 929         }
 930
 931         return data_count;
 932 }