373 lines
8.5 KiB
C
373 lines
8.5 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Pseudo-nulmodem driver
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* Mighty handy for use with serial console in Vmware
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/tty.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/poll.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/module.h>
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#include <sys/serial.h>
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#include <sys/signalvar.h>
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#include <sys/malloc.h>
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#include <sys/taskqueue.h>
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static MALLOC_DEFINE(M_NMDM, "nullmodem", "nullmodem data structures");
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static tsw_inwakeup_t nmdm_outwakeup;
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static tsw_outwakeup_t nmdm_inwakeup;
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static tsw_param_t nmdm_param;
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static tsw_modem_t nmdm_modem;
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static struct ttydevsw nmdm_class = {
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.tsw_flags = TF_NOPREFIX,
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.tsw_inwakeup = nmdm_inwakeup,
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.tsw_outwakeup = nmdm_outwakeup,
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.tsw_param = nmdm_param,
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.tsw_modem = nmdm_modem,
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};
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static void nmdm_task_tty(void *, int);
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struct nmdmsoftc;
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struct nmdmpart {
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struct tty *np_tty;
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int np_dcd;
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struct task np_task;
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struct nmdmpart *np_other;
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struct nmdmsoftc *np_pair;
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struct callout np_callout;
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u_long np_quota;
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u_long np_accumulator;
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int np_rate;
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int np_credits;
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#define QS 8 /* Quota shift */
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};
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struct nmdmsoftc {
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struct nmdmpart ns_part1;
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struct nmdmpart ns_part2;
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struct mtx ns_mtx;
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};
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static int nmdm_count = 0;
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static struct nmdmsoftc *
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nmdm_alloc(unsigned long unit)
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{
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struct nmdmsoftc *ns;
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struct tty *tp;
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atomic_add_int(&nmdm_count, 1);
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ns = malloc(sizeof(*ns), M_NMDM, M_WAITOK|M_ZERO);
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mtx_init(&ns->ns_mtx, "nmdm", NULL, MTX_DEF);
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/* Hook the pairs together. */
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ns->ns_part1.np_pair = ns;
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ns->ns_part1.np_other = &ns->ns_part2;
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TASK_INIT(&ns->ns_part1.np_task, 0, nmdm_task_tty, &ns->ns_part1);
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callout_init_mtx(&ns->ns_part1.np_callout, &ns->ns_mtx, 0);
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ns->ns_part2.np_pair = ns;
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ns->ns_part2.np_other = &ns->ns_part1;
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TASK_INIT(&ns->ns_part2.np_task, 0, nmdm_task_tty, &ns->ns_part2);
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callout_init_mtx(&ns->ns_part2.np_callout, &ns->ns_mtx, 0);
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/* Create device nodes. */
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tp = ns->ns_part1.np_tty = tty_alloc_mutex(&nmdm_class, &ns->ns_part1,
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&ns->ns_mtx);
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tty_makedev(tp, NULL, "nmdm%luA", unit);
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tp = ns->ns_part2.np_tty = tty_alloc_mutex(&nmdm_class, &ns->ns_part2,
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&ns->ns_mtx);
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tty_makedev(tp, NULL, "nmdm%luB", unit);
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return (ns);
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}
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static void
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nmdm_clone(void *arg, struct ucred *cred, char *name, int nameen,
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struct cdev **dev)
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{
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unsigned long unit;
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char *end;
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struct nmdmsoftc *ns;
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if (*dev != NULL)
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return;
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if (strncmp(name, "nmdm", 4) != 0)
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return;
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/* Device name must be "nmdm%lu%c", where %c is 'A' or 'B'. */
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name += 4;
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unit = strtoul(name, &end, 10);
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if (unit == ULONG_MAX || name == end)
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return;
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if ((end[0] != 'A' && end[0] != 'B') || end[1] != '\0')
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return;
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/* XXX: pass privileges? */
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ns = nmdm_alloc(unit);
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if (end[0] == 'A')
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*dev = ns->ns_part1.np_tty->t_dev;
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else
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*dev = ns->ns_part2.np_tty->t_dev;
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}
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static void
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nmdm_timeout(void *arg)
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{
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struct nmdmpart *np = arg;
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if (np->np_rate == 0)
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return;
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/*
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* Do a simple Floyd-Steinberg dither here to avoid FP math.
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* Wipe out unused quota from last tick.
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*/
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np->np_accumulator += np->np_credits;
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np->np_quota = np->np_accumulator >> QS;
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np->np_accumulator &= ((1 << QS) - 1);
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taskqueue_enqueue(taskqueue_swi, &np->np_task);
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callout_reset(&np->np_callout, np->np_rate, nmdm_timeout, np);
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}
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static void
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nmdm_task_tty(void *arg, int pending __unused)
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{
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struct tty *tp, *otp;
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struct nmdmpart *np = arg;
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char c;
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tp = np->np_tty;
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tty_lock(tp);
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otp = np->np_other->np_tty;
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KASSERT(otp != NULL, ("NULL otp in nmdmstart"));
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KASSERT(otp != tp, ("NULL otp == tp nmdmstart"));
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if (np->np_other->np_dcd) {
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if (!tty_opened(tp)) {
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np->np_other->np_dcd = 0;
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ttydisc_modem(otp, 0);
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}
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} else {
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if (tty_opened(tp)) {
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np->np_other->np_dcd = 1;
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ttydisc_modem(otp, 1);
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}
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}
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while (ttydisc_rint_poll(otp) > 0) {
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if (np->np_rate && !np->np_quota)
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break;
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if (ttydisc_getc(tp, &c, 1) != 1)
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break;
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np->np_quota--;
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ttydisc_rint(otp, c, 0);
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}
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ttydisc_rint_done(otp);
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tty_unlock(tp);
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}
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static int
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bits_per_char(struct termios *t)
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{
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int bits;
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bits = 1; /* start bit */
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switch (t->c_cflag & CSIZE) {
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case CS5: bits += 5; break;
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case CS6: bits += 6; break;
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case CS7: bits += 7; break;
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case CS8: bits += 8; break;
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}
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bits++; /* stop bit */
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if (t->c_cflag & PARENB)
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bits++;
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if (t->c_cflag & CSTOPB)
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bits++;
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return (bits);
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}
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static int
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nmdm_param(struct tty *tp, struct termios *t)
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{
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struct nmdmpart *np = tty_softc(tp);
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struct tty *tp2;
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int bpc, rate, speed, i;
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tp2 = np->np_other->np_tty;
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if (!((t->c_cflag | tp2->t_termios.c_cflag) & CDSR_OFLOW)) {
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np->np_rate = 0;
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np->np_other->np_rate = 0;
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return (0);
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}
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/*
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* DSRFLOW one either side enables rate-simulation for both
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* directions.
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* NB: the two directions may run at different rates.
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*/
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/* Find the larger of the number of bits transmitted */
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bpc = imax(bits_per_char(t), bits_per_char(&tp2->t_termios));
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for (i = 0; i < 2; i++) {
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/* Use the slower of our receive and their transmit rate */
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speed = imin(tp2->t_termios.c_ospeed, t->c_ispeed);
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if (speed == 0) {
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np->np_rate = 0;
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np->np_other->np_rate = 0;
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return (0);
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}
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speed <<= QS; /* [bit/sec, scaled] */
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speed /= bpc; /* [char/sec, scaled] */
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rate = (hz << QS) / speed; /* [hz per callout] */
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if (rate == 0)
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rate = 1;
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speed *= rate;
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speed /= hz; /* [(char/sec)/tick, scaled */
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np->np_credits = speed;
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np->np_rate = rate;
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callout_reset(&np->np_callout, rate, nmdm_timeout, np);
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/*
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* swap pointers for second pass so the other end gets
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* updated as well.
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*/
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np = np->np_other;
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t = &tp2->t_termios;
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tp2 = tp;
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}
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return (0);
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}
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static int
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nmdm_modem(struct tty *tp, int sigon, int sigoff)
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{
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struct nmdmpart *np = tty_softc(tp);
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int i = 0;
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if (sigon || sigoff) {
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if (sigon & SER_DTR)
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np->np_other->np_dcd = 1;
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if (sigoff & SER_DTR)
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np->np_other->np_dcd = 0;
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ttydisc_modem(np->np_other->np_tty, np->np_other->np_dcd);
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return (0);
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} else {
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if (np->np_dcd)
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i |= SER_DCD;
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if (np->np_other->np_dcd)
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i |= SER_DTR;
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return (i);
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}
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}
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static void
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nmdm_inwakeup(struct tty *tp)
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{
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struct nmdmpart *np = tty_softc(tp);
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/* We can receive again, so wake up the other side. */
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taskqueue_enqueue(taskqueue_swi, &np->np_other->np_task);
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}
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static void
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nmdm_outwakeup(struct tty *tp)
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{
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struct nmdmpart *np = tty_softc(tp);
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/* We can transmit again, so wake up our side. */
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taskqueue_enqueue(taskqueue_swi, &np->np_task);
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}
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/*
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* Module handling
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*/
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static int
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nmdm_modevent(module_t mod, int type, void *data)
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{
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static eventhandler_tag tag;
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switch(type) {
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case MOD_LOAD:
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tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000);
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if (tag == NULL)
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return (ENOMEM);
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break;
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case MOD_SHUTDOWN:
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break;
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case MOD_UNLOAD:
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if (nmdm_count != 0)
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return (EBUSY);
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EVENTHANDLER_DEREGISTER(dev_clone, tag);
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break;
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default:
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return (EOPNOTSUPP);
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}
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return (0);
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}
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DEV_MODULE(nmdm, nmdm_modevent, NULL);
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