freebsd-skq/sys/dev/uart/uart_tty.c
Ed Schouten bc093719ca Integrate the new MPSAFE TTY layer to the FreeBSD operating system.
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

  The old TTY layer has a driver model that is not abstract enough to
  make it friendly to use. A good example is the output path, where the
  device drivers directly access the output buffers. This means that an
  in-kernel PPP implementation must always convert network buffers into
  TTY buffers.

  If a PPP implementation would be built on top of the new TTY layer
  (still needs a hooks layer, though), it would allow the PPP
  implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

  With the old TTY layer, it isn't entirely safe to destroy TTY's from
  the system. This implementation has a two-step destructing design,
  where the driver first abandons the TTY. After all threads have left
  the TTY, the TTY layer calls a routine in the driver, which can be
  used to free resources (unit numbers, etc).

  The pts(4) driver also implements this feature, which means
  posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

  One of the major improvements is the per-TTY mutex, which is expected
  to improve scalability when compared to the old Giant locking.
  Another change is the unbuffered copying to userspace, which is both
  used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from:		//depot/projects/mpsafetty/...
Approved by:		philip (ex-mentor)
Discussed:		on the lists, at BSDCan, at the DevSummit
Sponsored by:		Snow B.V., the Netherlands
dcons(4) fixed by:	kan
2008-08-20 08:31:58 +00:00

376 lines
8.8 KiB
C

/*-
* Copyright (c) 2003 Marcel Moolenaar
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/fcntl.h>
#include <sys/interrupt.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <sys/termios.h>
#include <sys/tty.h>
#include <machine/resource.h>
#include <machine/stdarg.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_cpu.h>
#include "uart_if.h"
static cn_probe_t uart_cnprobe;
static cn_init_t uart_cninit;
static cn_term_t uart_cnterm;
static cn_getc_t uart_cngetc;
static cn_putc_t uart_cnputc;
CONSOLE_DRIVER(uart);
static struct uart_devinfo uart_console;
static void
uart_cnprobe(struct consdev *cp)
{
cp->cn_pri = CN_DEAD;
KASSERT(uart_console.cookie == NULL, ("foo"));
if (uart_cpu_getdev(UART_DEV_CONSOLE, &uart_console))
return;
if (uart_probe(&uart_console))
return;
strlcpy(cp->cn_name, uart_driver_name, sizeof(cp->cn_name));
cp->cn_pri = (boothowto & RB_SERIAL) ? CN_REMOTE : CN_NORMAL;
cp->cn_arg = &uart_console;
}
static void
uart_cninit(struct consdev *cp)
{
struct uart_devinfo *di;
/*
* Yedi trick: we need to be able to define cn_dev before we go
* single- or multi-user. The problem is that we don't know at
* this time what the device will be. Hence, we need to link from
* the uart_devinfo to the consdev that corresponds to it so that
* we can define cn_dev in uart_bus_attach() when we find the
* device during bus enumeration. That's when we'll know what the
* the unit number will be.
*/
di = cp->cn_arg;
KASSERT(di->cookie == NULL, ("foo"));
di->cookie = cp;
di->type = UART_DEV_CONSOLE;
uart_add_sysdev(di);
uart_init(di);
}
static void
uart_cnterm(struct consdev *cp)
{
uart_term(cp->cn_arg);
}
static void
uart_cnputc(struct consdev *cp, int c)
{
uart_putc(cp->cn_arg, c);
}
static int
uart_cngetc(struct consdev *cp)
{
return (uart_poll(cp->cn_arg));
}
static int
uart_tty_open(struct tty *tp)
{
struct uart_softc *sc;
sc = tty_softc(tp);
if (sc == NULL || sc->sc_leaving)
return (ENXIO);
sc->sc_opened = 1;
return (0);
}
static void
uart_tty_close(struct tty *tp)
{
struct uart_softc *sc;
sc = tty_softc(tp);
if (sc == NULL || sc->sc_leaving || !sc->sc_opened)
return;
if (sc->sc_hwiflow)
UART_IOCTL(sc, UART_IOCTL_IFLOW, 0);
if (sc->sc_hwoflow)
UART_IOCTL(sc, UART_IOCTL_OFLOW, 0);
if (sc->sc_sysdev == NULL)
UART_SETSIG(sc, SER_DDTR | SER_DRTS);
wakeup(sc);
sc->sc_opened = 0;
return;
}
static void
uart_tty_outwakeup(struct tty *tp)
{
struct uart_softc *sc;
sc = tty_softc(tp);
if (sc == NULL || sc->sc_leaving)
return;
/*
* Handle input flow control. Note that if we have hardware support,
* we don't do anything here. We continue to receive until our buffer
* is full. At that time we cannot empty the UART itself and it will
* de-assert RTS for us. In that situation we're completely stuffed.
* Without hardware support, we need to toggle RTS ourselves.
*/
if ((tp->t_termios.c_cflag & CRTS_IFLOW) && !sc->sc_hwiflow) {
#if 0
/*if ((tp->t_state & TS_TBLOCK) &&
(sc->sc_hwsig & SER_RTS))
UART_SETSIG(sc, SER_DRTS);
else */ if (/*!(tp->t_state & TS_TBLOCK) &&*/
!(sc->sc_hwsig & SER_RTS))
UART_SETSIG(sc, SER_DRTS|SER_RTS);
#endif
/* XXX: we should use inwakeup to implement this! */
if (!(sc->sc_hwsig & SER_RTS))
UART_SETSIG(sc, SER_DRTS|SER_RTS);
}
if (sc->sc_txbusy)
return;
sc->sc_txdatasz = ttydisc_getc(tp, sc->sc_txbuf, sc->sc_txfifosz);
if (sc->sc_txdatasz != 0)
UART_TRANSMIT(sc);
}
static int
uart_tty_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
{
struct uart_softc *sc;
sc = tty_softc(tp);
switch (cmd) {
case TIOCSBRK:
UART_IOCTL(sc, UART_IOCTL_BREAK, 1);
return (0);
case TIOCCBRK:
UART_IOCTL(sc, UART_IOCTL_BREAK, 0);
return (0);
default:
return pps_ioctl(cmd, data, &sc->sc_pps);
}
}
static int
uart_tty_param(struct tty *tp, struct termios *t)
{
struct uart_softc *sc;
int databits, parity, stopbits;
sc = tty_softc(tp);
if (sc == NULL || sc->sc_leaving)
return (ENODEV);
if (t->c_ispeed != t->c_ospeed && t->c_ospeed != 0)
return (EINVAL);
/* Fixate certain parameters for system devices. */
if (sc->sc_sysdev != NULL) {
t->c_ispeed = t->c_ospeed = sc->sc_sysdev->baudrate;
t->c_cflag |= CLOCAL;
t->c_cflag &= ~HUPCL;
}
if (t->c_ospeed == 0) {
UART_SETSIG(sc, SER_DDTR | SER_DRTS);
return (0);
}
switch (t->c_cflag & CSIZE) {
case CS5: databits = 5; break;
case CS6: databits = 6; break;
case CS7: databits = 7; break;
default: databits = 8; break;
}
stopbits = (t->c_cflag & CSTOPB) ? 2 : 1;
if (t->c_cflag & PARENB)
parity = (t->c_cflag & PARODD) ? UART_PARITY_ODD
: UART_PARITY_EVEN;
else
parity = UART_PARITY_NONE;
if (UART_PARAM(sc, t->c_ospeed, databits, stopbits, parity) != 0)
return (EINVAL);
UART_SETSIG(sc, SER_DDTR | SER_DTR);
/* Set input flow control state. */
if (!sc->sc_hwiflow) {
/* if ((t->c_cflag & CRTS_IFLOW) && (tp->t_state & TS_TBLOCK))
UART_SETSIG(sc, SER_DRTS);
else */
UART_SETSIG(sc, SER_DRTS | SER_RTS);
} else
UART_IOCTL(sc, UART_IOCTL_IFLOW, (t->c_cflag & CRTS_IFLOW));
/* Set output flow control state. */
if (sc->sc_hwoflow)
UART_IOCTL(sc, UART_IOCTL_OFLOW, (t->c_cflag & CCTS_OFLOW));
return (0);
}
static int
uart_tty_modem(struct tty *tp, int biton, int bitoff)
{
struct uart_softc *sc;
sc = tty_softc(tp);
if (biton != 0 || bitoff != 0)
UART_SETSIG(sc, SER_DELTA(bitoff|biton) | biton);
return (sc->sc_hwsig);
}
void
uart_tty_intr(void *arg)
{
struct uart_softc *sc = arg;
struct tty *tp;
int c, err = 0, pend, sig, xc;
if (sc->sc_leaving)
return;
pend = atomic_readandclear_32(&sc->sc_ttypend);
if (!(pend & SER_INT_MASK))
return;
tp = sc->sc_u.u_tty.tp;
tty_lock(tp);
if (pend & SER_INT_RXREADY) {
while (!uart_rx_empty(sc) /* && !(tp->t_state & TS_TBLOCK)*/) {
xc = uart_rx_get(sc);
c = xc & 0xff;
if (xc & UART_STAT_FRAMERR)
err |= TRE_FRAMING;
if (xc & UART_STAT_OVERRUN)
err |= TRE_OVERRUN;
if (xc & UART_STAT_PARERR)
err |= TRE_PARITY;
ttydisc_rint(tp, c, err);
}
}
if (pend & SER_INT_BREAK)
ttydisc_rint(tp, 0, TRE_BREAK);
if (pend & SER_INT_SIGCHG) {
sig = pend & SER_INT_SIGMASK;
if (sig & SER_DDCD)
ttydisc_modem(tp, sig & SER_DCD);
if ((sig & SER_DCTS) && (tp->t_termios.c_cflag & CCTS_OFLOW) &&
!sc->sc_hwoflow) {
if (sig & SER_CTS)
uart_tty_outwakeup(tp);
}
}
if (pend & SER_INT_TXIDLE)
uart_tty_outwakeup(tp);
ttydisc_rint_done(tp);
tty_unlock(tp);
}
static struct ttydevsw uart_tty_class = {
.tsw_flags = TF_INITLOCK|TF_CALLOUT,
.tsw_open = uart_tty_open,
.tsw_close = uart_tty_close,
.tsw_outwakeup = uart_tty_outwakeup,
.tsw_ioctl = uart_tty_ioctl,
.tsw_param = uart_tty_param,
.tsw_modem = uart_tty_modem,
};
int
uart_tty_attach(struct uart_softc *sc)
{
struct tty *tp;
int unit;
sc->sc_u.u_tty.tp = tp = tty_alloc(&uart_tty_class, sc, NULL);
unit = device_get_unit(sc->sc_dev);
if (sc->sc_sysdev != NULL && sc->sc_sysdev->type == UART_DEV_CONSOLE) {
sprintf(((struct consdev *)sc->sc_sysdev->cookie)->cn_name,
"ttyu%r", unit);
tty_init_console(tp, 0);
}
swi_add(&tty_intr_event, uart_driver_name, uart_tty_intr, sc, SWI_TTY,
INTR_TYPE_TTY, &sc->sc_softih);
tty_makedev(tp, NULL, "u%r", unit);
return (0);
}
int uart_tty_detach(struct uart_softc *sc)
{
struct tty *tp;
tp = sc->sc_u.u_tty.tp;
tty_lock(tp);
swi_remove(sc->sc_softih);
tty_rel_gone(tp);
return (0);
}