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1// SPDX-License-Identifier: GPL-2.0+2/************************************************************************3 * Copyright 2003 Digi International (www.digi.com)4 *5 * Copyright (C) 2004 IBM Corporation. All rights reserved.6 *7 * Contact Information:8 * Scott H Kilau <Scott_Kilau@digi.com>9 * Ananda Venkatarman <mansarov@us.ibm.com>10 * Modifications:11 * 01/19/06: changed jsm_input routine to use the dynamically allocated12 * tty_buffer changes. Contributors: Scott Kilau and Ananda V.13 ***********************************************************************/14#include <linux/tty.h>15#include <linux/tty_flip.h>16#include <linux/serial_reg.h>17#include <linux/delay.h> /* For udelay */18#include <linux/pci.h>19#include <linux/slab.h>20 21#include "jsm.h"22 23static DECLARE_BITMAP(linemap, MAXLINES);24 25static void jsm_carrier(struct jsm_channel *ch);26 27static inline int jsm_get_mstat(struct jsm_channel *ch)28{29 unsigned char mstat;30 int result;31 32 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "start\n");33 34 mstat = (ch->ch_mostat | ch->ch_mistat);35 36 result = 0;37 38 if (mstat & UART_MCR_DTR)39 result |= TIOCM_DTR;40 if (mstat & UART_MCR_RTS)41 result |= TIOCM_RTS;42 if (mstat & UART_MSR_CTS)43 result |= TIOCM_CTS;44 if (mstat & UART_MSR_DSR)45 result |= TIOCM_DSR;46 if (mstat & UART_MSR_RI)47 result |= TIOCM_RI;48 if (mstat & UART_MSR_DCD)49 result |= TIOCM_CD;50 51 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");52 return result;53}54 55static unsigned int jsm_tty_tx_empty(struct uart_port *port)56{57 return TIOCSER_TEMT;58}59 60/*61 * Return modem signals to ld.62 */63static unsigned int jsm_tty_get_mctrl(struct uart_port *port)64{65 int result;66 struct jsm_channel *channel =67 container_of(port, struct jsm_channel, uart_port);68 69 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");70 71 result = jsm_get_mstat(channel);72 73 if (result < 0)74 return -ENXIO;75 76 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");77 78 return result;79}80 81/*82 * jsm_set_modem_info()83 *84 * Set modem signals, called by ld.85 */86static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)87{88 struct jsm_channel *channel =89 container_of(port, struct jsm_channel, uart_port);90 91 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");92 93 if (mctrl & TIOCM_RTS)94 channel->ch_mostat |= UART_MCR_RTS;95 else96 channel->ch_mostat &= ~UART_MCR_RTS;97 98 if (mctrl & TIOCM_DTR)99 channel->ch_mostat |= UART_MCR_DTR;100 else101 channel->ch_mostat &= ~UART_MCR_DTR;102 103 channel->ch_bd->bd_ops->assert_modem_signals(channel);104 105 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");106 udelay(10);107}108 109/*110 * jsm_tty_write()111 *112 * Take data from the user or kernel and send it out to the FEP.113 * In here exists all the Transparent Print magic as well.114 */115static void jsm_tty_write(struct uart_port *port)116{117 struct jsm_channel *channel;118 119 channel = container_of(port, struct jsm_channel, uart_port);120 channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);121}122 123static void jsm_tty_start_tx(struct uart_port *port)124{125 struct jsm_channel *channel =126 container_of(port, struct jsm_channel, uart_port);127 128 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");129 130 channel->ch_flags &= ~(CH_STOP);131 jsm_tty_write(port);132 133 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");134}135 136static void jsm_tty_stop_tx(struct uart_port *port)137{138 struct jsm_channel *channel =139 container_of(port, struct jsm_channel, uart_port);140 141 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");142 143 channel->ch_flags |= (CH_STOP);144 145 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");146}147 148static void jsm_tty_send_xchar(struct uart_port *port, char ch)149{150 unsigned long lock_flags;151 struct jsm_channel *channel =152 container_of(port, struct jsm_channel, uart_port);153 struct ktermios *termios;154 155 uart_port_lock_irqsave(port, &lock_flags);156 termios = &port->state->port.tty->termios;157 if (ch == termios->c_cc[VSTART])158 channel->ch_bd->bd_ops->send_start_character(channel);159 160 if (ch == termios->c_cc[VSTOP])161 channel->ch_bd->bd_ops->send_stop_character(channel);162 uart_port_unlock_irqrestore(port, lock_flags);163}164 165static void jsm_tty_stop_rx(struct uart_port *port)166{167 struct jsm_channel *channel =168 container_of(port, struct jsm_channel, uart_port);169 170 channel->ch_bd->bd_ops->disable_receiver(channel);171}172 173static void jsm_tty_break(struct uart_port *port, int break_state)174{175 unsigned long lock_flags;176 struct jsm_channel *channel =177 container_of(port, struct jsm_channel, uart_port);178 179 uart_port_lock_irqsave(port, &lock_flags);180 if (break_state == -1)181 channel->ch_bd->bd_ops->send_break(channel);182 else183 channel->ch_bd->bd_ops->clear_break(channel);184 185 uart_port_unlock_irqrestore(port, lock_flags);186}187 188static int jsm_tty_open(struct uart_port *port)189{190 unsigned long lock_flags;191 struct jsm_board *brd;192 struct jsm_channel *channel =193 container_of(port, struct jsm_channel, uart_port);194 struct ktermios *termios;195 196 /* Get board pointer from our array of majors we have allocated */197 brd = channel->ch_bd;198 199 /*200 * Allocate channel buffers for read/write/error.201 * Set flag, so we don't get trounced on.202 */203 channel->ch_flags |= (CH_OPENING);204 205 /* Drop locks, as malloc with GFP_KERNEL can sleep */206 207 if (!channel->ch_rqueue) {208 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);209 if (!channel->ch_rqueue) {210 jsm_dbg(INIT, &channel->ch_bd->pci_dev,211 "unable to allocate read queue buf\n");212 return -ENOMEM;213 }214 }215 if (!channel->ch_equeue) {216 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);217 if (!channel->ch_equeue) {218 jsm_dbg(INIT, &channel->ch_bd->pci_dev,219 "unable to allocate error queue buf\n");220 return -ENOMEM;221 }222 }223 224 channel->ch_flags &= ~(CH_OPENING);225 /*226 * Initialize if neither terminal is open.227 */228 jsm_dbg(OPEN, &channel->ch_bd->pci_dev,229 "jsm_open: initializing channel in open...\n");230 231 /*232 * Flush input queues.233 */234 channel->ch_r_head = channel->ch_r_tail = 0;235 channel->ch_e_head = channel->ch_e_tail = 0;236 237 brd->bd_ops->flush_uart_write(channel);238 brd->bd_ops->flush_uart_read(channel);239 240 channel->ch_flags = 0;241 channel->ch_cached_lsr = 0;242 channel->ch_stops_sent = 0;243 244 uart_port_lock_irqsave(port, &lock_flags);245 termios = &port->state->port.tty->termios;246 channel->ch_c_cflag = termios->c_cflag;247 channel->ch_c_iflag = termios->c_iflag;248 channel->ch_c_oflag = termios->c_oflag;249 channel->ch_c_lflag = termios->c_lflag;250 channel->ch_startc = termios->c_cc[VSTART];251 channel->ch_stopc = termios->c_cc[VSTOP];252 253 /* Tell UART to init itself */254 brd->bd_ops->uart_init(channel);255 256 /*257 * Run param in case we changed anything258 */259 brd->bd_ops->param(channel);260 261 jsm_carrier(channel);262 263 channel->ch_open_count++;264 uart_port_unlock_irqrestore(port, lock_flags);265 266 jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");267 return 0;268}269 270static void jsm_tty_close(struct uart_port *port)271{272 struct jsm_board *bd;273 struct jsm_channel *channel =274 container_of(port, struct jsm_channel, uart_port);275 276 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");277 278 bd = channel->ch_bd;279 280 channel->ch_flags &= ~(CH_STOPI);281 282 channel->ch_open_count--;283 284 /*285 * If we have HUPCL set, lower DTR and RTS286 */287 if (channel->ch_c_cflag & HUPCL) {288 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev,289 "Close. HUPCL set, dropping DTR/RTS\n");290 291 /* Drop RTS/DTR */292 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);293 bd->bd_ops->assert_modem_signals(channel);294 }295 296 /* Turn off UART interrupts for this port */297 channel->ch_bd->bd_ops->uart_off(channel);298 299 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "finish\n");300}301 302static void jsm_tty_set_termios(struct uart_port *port,303 struct ktermios *termios,304 const struct ktermios *old_termios)305{306 unsigned long lock_flags;307 struct jsm_channel *channel =308 container_of(port, struct jsm_channel, uart_port);309 310 uart_port_lock_irqsave(port, &lock_flags);311 channel->ch_c_cflag = termios->c_cflag;312 channel->ch_c_iflag = termios->c_iflag;313 channel->ch_c_oflag = termios->c_oflag;314 channel->ch_c_lflag = termios->c_lflag;315 channel->ch_startc = termios->c_cc[VSTART];316 channel->ch_stopc = termios->c_cc[VSTOP];317 318 channel->ch_bd->bd_ops->param(channel);319 jsm_carrier(channel);320 uart_port_unlock_irqrestore(port, lock_flags);321}322 323static const char *jsm_tty_type(struct uart_port *port)324{325 return "jsm";326}327 328static void jsm_tty_release_port(struct uart_port *port)329{330}331 332static int jsm_tty_request_port(struct uart_port *port)333{334 return 0;335}336 337static void jsm_config_port(struct uart_port *port, int flags)338{339 port->type = PORT_JSM;340}341 342static const struct uart_ops jsm_ops = {343 .tx_empty = jsm_tty_tx_empty,344 .set_mctrl = jsm_tty_set_mctrl,345 .get_mctrl = jsm_tty_get_mctrl,346 .stop_tx = jsm_tty_stop_tx,347 .start_tx = jsm_tty_start_tx,348 .send_xchar = jsm_tty_send_xchar,349 .stop_rx = jsm_tty_stop_rx,350 .break_ctl = jsm_tty_break,351 .startup = jsm_tty_open,352 .shutdown = jsm_tty_close,353 .set_termios = jsm_tty_set_termios,354 .type = jsm_tty_type,355 .release_port = jsm_tty_release_port,356 .request_port = jsm_tty_request_port,357 .config_port = jsm_config_port,358};359 360/*361 * jsm_tty_init()362 *363 * Init the tty subsystem. Called once per board after board has been364 * downloaded and init'ed.365 */366int jsm_tty_init(struct jsm_board *brd)367{368 int i;369 void __iomem *vaddr;370 struct jsm_channel *ch;371 372 if (!brd)373 return -ENXIO;374 375 jsm_dbg(INIT, &brd->pci_dev, "start\n");376 377 /*378 * Initialize board structure elements.379 */380 381 brd->nasync = brd->maxports;382 383 /*384 * Allocate channel memory that might not have been allocated385 * when the driver was first loaded.386 */387 for (i = 0; i < brd->nasync; i++) {388 if (!brd->channels[i]) {389 390 /*391 * Okay to malloc with GFP_KERNEL, we are not at392 * interrupt context, and there are no locks held.393 */394 brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);395 if (!brd->channels[i]) {396 jsm_dbg(CORE, &brd->pci_dev,397 "%s:%d Unable to allocate memory for channel struct\n",398 __FILE__, __LINE__);399 }400 }401 }402 403 ch = brd->channels[0];404 vaddr = brd->re_map_membase;405 406 /* Set up channel variables */407 for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {408 409 if (!brd->channels[i])410 continue;411 412 spin_lock_init(&ch->ch_lock);413 414 if (brd->bd_uart_offset == 0x200)415 ch->ch_neo_uart = vaddr + (brd->bd_uart_offset * i);416 else417 ch->ch_cls_uart = vaddr + (brd->bd_uart_offset * i);418 419 ch->ch_bd = brd;420 ch->ch_portnum = i;421 422 /* .25 second delay */423 ch->ch_close_delay = 250;424 425 init_waitqueue_head(&ch->ch_flags_wait);426 }427 428 jsm_dbg(INIT, &brd->pci_dev, "finish\n");429 return 0;430}431 432int jsm_uart_port_init(struct jsm_board *brd)433{434 int i, rc;435 unsigned int line;436 437 if (!brd)438 return -ENXIO;439 440 jsm_dbg(INIT, &brd->pci_dev, "start\n");441 442 /*443 * Initialize board structure elements.444 */445 446 brd->nasync = brd->maxports;447 448 /* Set up channel variables */449 for (i = 0; i < brd->nasync; i++) {450 451 if (!brd->channels[i])452 continue;453 454 brd->channels[i]->uart_port.irq = brd->irq;455 brd->channels[i]->uart_port.uartclk = 14745600;456 brd->channels[i]->uart_port.type = PORT_JSM;457 brd->channels[i]->uart_port.iotype = UPIO_MEM;458 brd->channels[i]->uart_port.membase = brd->re_map_membase;459 brd->channels[i]->uart_port.fifosize = 16;460 brd->channels[i]->uart_port.ops = &jsm_ops;461 line = find_first_zero_bit(linemap, MAXLINES);462 if (line >= MAXLINES) {463 printk(KERN_INFO "jsm: linemap is full, added device failed\n");464 continue;465 } else466 set_bit(line, linemap);467 brd->channels[i]->uart_port.line = line;468 rc = uart_add_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);469 if (rc) {470 printk(KERN_INFO "jsm: Port %d failed. Aborting...\n", i);471 return rc;472 } else473 printk(KERN_INFO "jsm: Port %d added\n", i);474 }475 476 jsm_dbg(INIT, &brd->pci_dev, "finish\n");477 return 0;478}479 480int jsm_remove_uart_port(struct jsm_board *brd)481{482 int i;483 struct jsm_channel *ch;484 485 if (!brd)486 return -ENXIO;487 488 jsm_dbg(INIT, &brd->pci_dev, "start\n");489 490 /*491 * Initialize board structure elements.492 */493 494 brd->nasync = brd->maxports;495 496 /* Set up channel variables */497 for (i = 0; i < brd->nasync; i++) {498 499 if (!brd->channels[i])500 continue;501 502 ch = brd->channels[i];503 504 clear_bit(ch->uart_port.line, linemap);505 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);506 }507 508 jsm_dbg(INIT, &brd->pci_dev, "finish\n");509 return 0;510}511 512void jsm_input(struct jsm_channel *ch)513{514 struct jsm_board *bd;515 struct tty_struct *tp;516 struct tty_port *port;517 u32 rmask;518 u16 head;519 u16 tail;520 int data_len;521 unsigned long lock_flags;522 int len = 0;523 int s = 0;524 int i = 0;525 526 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");527 528 port = &ch->uart_port.state->port;529 tp = port->tty;530 531 bd = ch->ch_bd;532 if (!bd)533 return;534 535 spin_lock_irqsave(&ch->ch_lock, lock_flags);536 537 /*538 *Figure the number of characters in the buffer.539 *Exit immediately if none.540 */541 542 rmask = RQUEUEMASK;543 544 head = ch->ch_r_head & rmask;545 tail = ch->ch_r_tail & rmask;546 547 data_len = (head - tail) & rmask;548 if (data_len == 0) {549 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);550 return;551 }552 553 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");554 555 /*556 *If the device is not open, or CREAD is off, flush557 *input data and return immediately.558 */559 if (!tp || !C_CREAD(tp)) {560 561 jsm_dbg(READ, &ch->ch_bd->pci_dev,562 "input. dropping %d bytes on port %d...\n",563 data_len, ch->ch_portnum);564 ch->ch_r_head = tail;565 566 /* Force queue flow control to be released, if needed */567 jsm_check_queue_flow_control(ch);568 569 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);570 return;571 }572 573 /*574 * If we are throttled, simply don't read any data.575 */576 if (ch->ch_flags & CH_STOPI) {577 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);578 jsm_dbg(READ, &ch->ch_bd->pci_dev,579 "Port %d throttled, not reading any data. head: %x tail: %x\n",580 ch->ch_portnum, head, tail);581 return;582 }583 584 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");585 586 len = tty_buffer_request_room(port, data_len);587 588 /*589 * len now contains the most amount of data we can copy,590 * bounded either by the flip buffer size or the amount591 * of data the card actually has pending...592 */593 while (len) {594 s = ((head >= tail) ? head : RQUEUESIZE) - tail;595 s = min(s, len);596 597 if (s <= 0)598 break;599 600 /*601 * If conditions are such that ld needs to see all602 * UART errors, we will have to walk each character603 * and error byte and send them to the buffer one at604 * a time.605 */606 607 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {608 for (i = 0; i < s; i++) {609 u8 chr = ch->ch_rqueue[tail + i];610 u8 error = ch->ch_equeue[tail + i];611 char flag = TTY_NORMAL;612 613 /*614 * Give the Linux ld the flags in the format it615 * likes.616 */617 if (error & UART_LSR_BI)618 flag = TTY_BREAK;619 else if (error & UART_LSR_PE)620 flag = TTY_PARITY;621 else if (error & UART_LSR_FE)622 flag = TTY_FRAME;623 624 tty_insert_flip_char(port, chr, flag);625 }626 } else {627 tty_insert_flip_string(port, ch->ch_rqueue + tail, s);628 }629 tail += s;630 len -= s;631 /* Flip queue if needed */632 tail &= rmask;633 }634 635 ch->ch_r_tail = tail & rmask;636 ch->ch_e_tail = tail & rmask;637 jsm_check_queue_flow_control(ch);638 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);639 640 /* Tell the tty layer its okay to "eat" the data now */641 tty_flip_buffer_push(port);642 643 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");644}645 646static void jsm_carrier(struct jsm_channel *ch)647{648 struct jsm_board *bd;649 650 int virt_carrier = 0;651 int phys_carrier = 0;652 653 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");654 655 bd = ch->ch_bd;656 if (!bd)657 return;658 659 if (ch->ch_mistat & UART_MSR_DCD) {660 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "mistat: %x D_CD: %x\n",661 ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);662 phys_carrier = 1;663 }664 665 if (ch->ch_c_cflag & CLOCAL)666 virt_carrier = 1;667 668 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "DCD: physical: %d virt: %d\n",669 phys_carrier, virt_carrier);670 671 /*672 * Test for a VIRTUAL carrier transition to HIGH.673 */674 if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {675 676 /*677 * When carrier rises, wake any threads waiting678 * for carrier in the open routine.679 */680 681 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "carrier: virt DCD rose\n");682 683 if (waitqueue_active(&(ch->ch_flags_wait)))684 wake_up_interruptible(&ch->ch_flags_wait);685 }686 687 /*688 * Test for a PHYSICAL carrier transition to HIGH.689 */690 if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {691 692 /*693 * When carrier rises, wake any threads waiting694 * for carrier in the open routine.695 */696 697 jsm_dbg(CARR, &ch->ch_bd->pci_dev,698 "carrier: physical DCD rose\n");699 700 if (waitqueue_active(&(ch->ch_flags_wait)))701 wake_up_interruptible(&ch->ch_flags_wait);702 }703 704 /*705 * Test for a PHYSICAL transition to low, so long as we aren't706 * currently ignoring physical transitions (which is what "virtual707 * carrier" indicates).708 *709 * The transition of the virtual carrier to low really doesn't710 * matter... it really only means "ignore carrier state", not711 * "make pretend that carrier is there".712 */713 if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)714 && (phys_carrier == 0)) {715 /*716 * When carrier drops:717 *718 * Drop carrier on all open units.719 *720 * Flush queues, waking up any task waiting in the721 * line discipline.722 *723 * Send a hangup to the control terminal.724 *725 * Enable all select calls.726 */727 if (waitqueue_active(&(ch->ch_flags_wait)))728 wake_up_interruptible(&ch->ch_flags_wait);729 }730 731 /*732 * Make sure that our cached values reflect the current reality.733 */734 if (virt_carrier == 1)735 ch->ch_flags |= CH_FCAR;736 else737 ch->ch_flags &= ~CH_FCAR;738 739 if (phys_carrier == 1)740 ch->ch_flags |= CH_CD;741 else742 ch->ch_flags &= ~CH_CD;743}744 745 746void jsm_check_queue_flow_control(struct jsm_channel *ch)747{748 struct board_ops *bd_ops = ch->ch_bd->bd_ops;749 int qleft;750 751 /* Store how much space we have left in the queue */752 qleft = ch->ch_r_tail - ch->ch_r_head - 1;753 if (qleft < 0)754 qleft += RQUEUEMASK + 1;755 756 /*757 * Check to see if we should enforce flow control on our queue because758 * the ld (or user) isn't reading data out of our queue fast enuf.759 *760 * NOTE: This is done based on what the current flow control of the761 * port is set for.762 *763 * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.764 * This will cause the UART's FIFO to back up, and force765 * the RTS signal to be dropped.766 * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to767 * the other side, in hopes it will stop sending data to us.768 * 3) NONE - Nothing we can do. We will simply drop any extra data769 * that gets sent into us when the queue fills up.770 */771 if (qleft < 256) {772 /* HWFLOW */773 if (ch->ch_c_cflag & CRTSCTS) {774 if (!(ch->ch_flags & CH_RECEIVER_OFF)) {775 bd_ops->disable_receiver(ch);776 ch->ch_flags |= (CH_RECEIVER_OFF);777 jsm_dbg(READ, &ch->ch_bd->pci_dev,778 "Internal queue hit hilevel mark (%d)! Turning off interrupts\n",779 qleft);780 }781 }782 /* SWFLOW */783 else if (ch->ch_c_iflag & IXOFF) {784 if (ch->ch_stops_sent <= MAX_STOPS_SENT) {785 bd_ops->send_stop_character(ch);786 ch->ch_stops_sent++;787 jsm_dbg(READ, &ch->ch_bd->pci_dev,788 "Sending stop char! Times sent: %x\n",789 ch->ch_stops_sent);790 }791 }792 }793 794 /*795 * Check to see if we should unenforce flow control because796 * 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 the799 * 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 to805 * 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 the807 * 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_dbg(READ, &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_dbg(READ, &ch->ch_bd->pci_dev,825 "Sending start char!\n");826 }827 }828}829