freebsd-dev/sys/dev/nmdm/nmdm.c
2006-01-04 08:34:23 +00:00

460 lines
10 KiB
C

/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Pseudo-nulmodem driver
* Mighty handy for use with serial console in Vmware
*/
#include "opt_compat.h"
#include "opt_tty.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/tty.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/poll.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/serial.h>
#include <sys/signalvar.h>
#include <sys/malloc.h>
#include <sys/taskqueue.h>
MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
static d_close_t nmdmclose;
static t_modem_t nmdmmodem;
static d_open_t nmdmopen;
static t_oproc_t nmdmoproc;
static t_param_t nmdmparam;
static t_stop_t nmdmstop;
static struct cdevsw nmdm_cdevsw = {
.d_version = D_VERSION,
.d_open = nmdmopen,
.d_close = nmdmclose,
.d_name = "nmdn",
.d_flags = D_TTY | D_PSEUDO | D_NEEDGIANT,
};
#define BUFSIZ 100 /* Chunk size iomoved to/from user */
#define NMDM_MAX_NUM 128 /* Artificially limit # devices. */
#define PF_STOPPED 0x10 /* user told stopped */
#define BFLAG CLONE_FLAG0
struct softpart {
struct tty *nm_tty;
struct cdev *dev;
int nm_dcd;
struct task pt_task;
struct softpart *other;
struct callout co;
u_long quota;
u_long accumulator;
int rate;
int credits;
#define QS 8 /* Quota shift */
};
struct nm_softc {
TAILQ_ENTRY(nm_softc) pt_list;
int pt_flags;
struct softpart part1, part2;
struct prison *pt_prison;
};
static struct clonedevs *nmdmclones;
static TAILQ_HEAD(,nm_softc) nmdmhead = TAILQ_HEAD_INITIALIZER(nmdmhead);
static void
nmdm_clone(void *arg, struct ucred *cred, char *name, int nameen,
struct cdev **dev)
{
int i, unit;
char *p;
struct cdev *d1, *d2;
if (*dev != NULL)
return;
if (strcmp(name, "nmdm") == 0) {
p = NULL;
unit = -1;
} else {
i = dev_stdclone(name, &p, "nmdm", &unit);
if (i == 0)
return;
if (p[0] != '\0' && p[0] != 'A' && p[0] != 'B')
return;
else if (p[0] != '\0' && p[1] != '\0')
return;
}
i = clone_create(&nmdmclones, &nmdm_cdevsw, &unit, &d1, 0);
if (i) {
d1 = make_dev(&nmdm_cdevsw, unit2minor(unit),
0, 0, 0666, "nmdm%dA", unit);
if (d1 == NULL)
return;
d2 = make_dev(&nmdm_cdevsw, unit2minor(unit) | BFLAG,
0, 0, 0666, "nmdm%dB", unit);
if (d2 == NULL) {
destroy_dev(d1);
return;
}
d2->si_drv2 = d1;
d1->si_drv2 = d2;
dev_depends(d1, d2);
dev_depends(d2, d1);
d1->si_flags |= SI_CHEAPCLONE;
d2->si_flags |= SI_CHEAPCLONE;
}
if (p != NULL && p[0] == 'B')
*dev = d1->si_drv2;
else
*dev = d1;
dev_ref(*dev);
}
static void
nmdm_timeout(void *arg)
{
struct softpart *sp;
sp = arg;
if (sp->rate == 0)
return;
/*
* Do a simple Floyd-Steinberg dither here to avoid FP math.
* Wipe out unused quota from last tick.
*/
sp->accumulator += sp->credits;
sp->quota = sp->accumulator >> QS;
sp->accumulator &= ((1 << QS) - 1);
taskqueue_enqueue(taskqueue_swi_giant, &sp->pt_task);
callout_reset(&sp->co, sp->rate, nmdm_timeout, arg);
}
static void
nmdm_task_tty(void *arg, int pending __unused)
{
struct tty *tp, *otp;
struct softpart *sp;
int c;
tp = arg;
sp = tp->t_sc;
otp = sp->other->nm_tty;
KASSERT(otp != NULL, ("NULL otp in nmdmstart"));
KASSERT(otp != tp, ("NULL otp == tp nmdmstart"));
if (sp->other->nm_dcd) {
if (!(tp->t_state & TS_ISOPEN)) {
sp->other->nm_dcd = 0;
(void)ttyld_modem(otp, 0);
}
} else {
if (tp->t_state & TS_ISOPEN) {
sp->other->nm_dcd = 1;
(void)ttyld_modem(otp, 1);
}
}
if (tp->t_state & TS_TTSTOP)
return;
while (tp->t_outq.c_cc != 0) {
if (sp->rate && !sp->quota)
return;
if (otp->t_state & TS_TBLOCK)
return;
sp->quota--;
c = getc(&tp->t_outq);
if (otp->t_state & TS_ISOPEN)
ttyld_rint(otp, c);
}
if (tp->t_outq.c_cc == 0)
ttwwakeup(tp);
}
/*
* This function creates and initializes a pair of ttys.
*/
static void
nmdminit(struct cdev *dev1)
{
struct cdev *dev2;
struct nm_softc *pt;
dev2 = dev1->si_drv2;
dev1->si_flags &= ~SI_CHEAPCLONE;
dev2->si_flags &= ~SI_CHEAPCLONE;
pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
TAILQ_INSERT_TAIL(&nmdmhead, pt, pt_list);
dev1->si_drv1 = dev2->si_drv1 = pt;
pt->part1.dev = dev1;
pt->part2.dev = dev2;
pt->part1.nm_tty = ttyalloc();
pt->part1.nm_tty->t_oproc = nmdmoproc;
pt->part1.nm_tty->t_stop = nmdmstop;
pt->part1.nm_tty->t_modem = nmdmmodem;
pt->part1.nm_tty->t_param = nmdmparam;
pt->part1.nm_tty->t_dev = dev1;
pt->part1.nm_tty->t_sc = &pt->part1;
TASK_INIT(&pt->part1.pt_task, 0, nmdm_task_tty, pt->part1.nm_tty);
callout_init(&pt->part1.co, 0);
pt->part2.nm_tty = ttyalloc();
pt->part2.nm_tty->t_oproc = nmdmoproc;
pt->part2.nm_tty->t_stop = nmdmstop;
pt->part2.nm_tty->t_modem = nmdmmodem;
pt->part2.nm_tty->t_param = nmdmparam;
pt->part2.nm_tty->t_dev = dev2;
pt->part2.nm_tty->t_sc = &pt->part2;
TASK_INIT(&pt->part2.pt_task, 0, nmdm_task_tty, pt->part2.nm_tty);
callout_init(&pt->part2.co, 0);
pt->part1.other = &pt->part2;
pt->part2.other = &pt->part1;
dev1->si_tty = pt->part1.nm_tty;
dev1->si_drv1 = pt;
dev2->si_tty = pt->part2.nm_tty;
dev2->si_drv1 = pt;
}
/*
* Device opened from userland
*/
static int
nmdmopen(struct cdev *dev, int flag, int devtype, struct thread *td)
{
struct tty *tp, *tp2;
int error;
struct nm_softc *pti;
struct softpart *sp;
if (dev->si_drv1 == NULL)
nmdminit(dev);
pti = dev->si_drv1;
if (pti->pt_prison != td->td_ucred->cr_prison)
return (EBUSY);
tp = dev->si_tty;
sp = tp->t_sc;
tp2 = sp->other->nm_tty;
if ((tp->t_state & TS_ISOPEN) == 0) {
ttyinitmode(tp, 0, 0);
ttsetwater(tp); /* XXX ? */
} else if (tp->t_state & TS_XCLUDE && suser(td)) {
return (EBUSY);
}
error = ttyld_open(tp, dev);
return (error);
}
static int
bits_per_char(struct termios *t)
{
int bits;
bits = 1; /* start bit */
switch (t->c_cflag & CSIZE) {
case CS5: bits += 5; break;
case CS6: bits += 6; break;
case CS7: bits += 7; break;
case CS8: bits += 8; break;
}
bits++; /* stop bit */
if (t->c_cflag & PARENB)
bits++;
if (t->c_cflag & CSTOPB)
bits++;
return (bits);
}
static int
nmdmparam(struct tty *tp, struct termios *t)
{
struct softpart *sp;
struct tty *tp2;
int bpc, rate, speed, i;
sp = tp->t_sc;
tp2 = sp->other->nm_tty;
if (!((t->c_cflag | tp2->t_cflag) & CDSR_OFLOW)) {
sp->rate = 0;
sp->other->rate = 0;
return (0);
}
/*
* DSRFLOW one either side enables rate-simulation for both
* directions.
* NB: the two directions may run at different rates.
*/
/* Find the larger of the number of bits transmitted */
bpc = imax(bits_per_char(t), bits_per_char(&tp2->t_termios));
for (i = 0; i < 2; i++) {
/* Use the slower of our receive and their transmit rate */
speed = imin(tp2->t_ospeed, t->c_ispeed);
if (speed == 0) {
sp->rate = 0;
sp->other->rate = 0;
return (0);
}
speed <<= QS; /* [bit/sec, scaled] */
speed /= bpc; /* [char/sec, scaled] */
rate = (hz << QS) / speed; /* [hz per callout] */
if (rate == 0)
rate = 1;
speed *= rate;
speed /= hz; /* [(char/sec)/tick, scaled */
sp->credits = speed;
sp->rate = rate;
callout_reset(&sp->co, rate, nmdm_timeout, sp);
/*
* swap pointers for second pass so the other end gets
* updated as well.
*/
sp = sp->other;
t = &tp2->t_termios;
tp2 = tp;
}
return (0);
}
static int
nmdmmodem(struct tty *tp, int sigon, int sigoff)
{
struct softpart *sp;
int i;
sp = tp->t_sc;
if (sigon || sigoff) {
if (sigon & SER_DTR)
sp->other->nm_dcd = 1;
if (sigoff & SER_DTR)
sp->other->nm_dcd = 0;
ttyld_modem(sp->other->nm_tty, sp->other->nm_dcd);
return (0);
} else {
i = 0;
if (sp->nm_dcd)
i |= SER_DCD;
if (sp->other->nm_dcd)
i |= SER_DTR;
return (i);
}
}
static int
nmdmclose(struct cdev *dev, int flag, int mode, struct thread *td)
{
return (tty_close(dev->si_tty));
}
static void
nmdmoproc(struct tty *tp)
{
struct softpart *pt;
pt = tp->t_sc;
taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
}
static void
nmdmstop(struct tty *tp, int flush)
{
struct softpart *pt;
pt = tp->t_sc;
taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
}
/*
* Module handling
*/
static int
nmdm_modevent(module_t mod, int type, void *data)
{
static eventhandler_tag tag;
struct nm_softc *pt, *tpt;
int error = 0;
switch(type) {
case MOD_LOAD:
clone_setup(&nmdmclones);
tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000);
if (tag == NULL)
return (ENOMEM);
break;
case MOD_SHUTDOWN:
/* FALLTHROUGH */
case MOD_UNLOAD:
EVENTHANDLER_DEREGISTER(dev_clone, tag);
TAILQ_FOREACH_SAFE(pt, &nmdmhead, pt_list, tpt) {
destroy_dev(pt->part1.dev);
TAILQ_REMOVE(&nmdmhead, pt, pt_list);
free(pt, M_NLMDM);
}
clone_cleanup(&nmdmclones);
break;
default:
error = EOPNOTSUPP;
}
return (error);
}
DEV_MODULE(nmdm, nmdm_modevent, NULL);