freebsd-dev/sys/boot/i386/libi386/comconsole.c
Ian Dowse 4832a19173 Add a "comconsole_speed" loader variable that can be used to change
the serial console speed (i386 and amd64 only). If the previous
stage boot loader requested a serial console (RB_SERIAL or RB_MULTIPLE)
then the default speed is determined from the current serial port
speed. Otherwise it is set to 9600 or the value of BOOT_COMCONSOLE_SPEED
at compile time.

This makes it possible to set the serial port speed once in
/boot.config and the setting will propagate to boot2, loader and
the kernel serial console.
2005-08-18 01:39:43 +00:00

214 lines
5.1 KiB
C

/*-
* Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
*
* 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 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 AUTHOR 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("$FreeBSD$");
#include <stand.h>
#include <bootstrap.h>
#include <machine/cpufunc.h>
#include <dev/ic/ns16550.h>
#include "libi386.h"
#define COMC_FMT 0x3 /* 8N1 */
#define COMC_TXWAIT 0x40000 /* transmit timeout */
#define COMC_BPS(x) (115200 / (x)) /* speed to DLAB divisor */
#define COMC_DIV2BPS(x) (115200 / (x)) /* DLAB divisor to speed */
#ifndef COMPORT
#define COMPORT 0x3f8
#endif
#ifndef COMSPEED
#define COMSPEED 9600
#endif
static void comc_probe(struct console *cp);
static int comc_init(int arg);
static void comc_putchar(int c);
static int comc_getchar(void);
static int comc_getspeed(void);
static int comc_ischar(void);
static int comc_parsespeed(const char *string);
static void comc_setup(int speed);
static int comc_speed_set(struct env_var *ev, int flags,
const void *value);
static int comc_started;
static int comc_curspeed;
struct console comconsole = {
"comconsole",
"serial port",
0,
comc_probe,
comc_init,
comc_putchar,
comc_getchar,
comc_ischar
};
static void
comc_probe(struct console *cp)
{
char speedbuf[16];
char *cons, *speedenv;
int speed;
/* XXX check the BIOS equipment list? */
cp->c_flags |= (C_PRESENTIN | C_PRESENTOUT);
if (comc_curspeed == 0) {
comc_curspeed = COMSPEED;
/*
* Assume that the speed was set by an earlier boot loader if
* comconsole is already the preferred console.
*/
cons = getenv("console");
if ((cons != NULL && strcmp(cons, comconsole.c_name) == 0) ||
getenv("boot_multicons") != NULL) {
comc_curspeed = comc_getspeed();
}
speedenv = getenv("comconsole_speed");
if (speedenv != NULL) {
speed = comc_parsespeed(speedenv);
if (speed > 0)
comc_curspeed = speed;
}
sprintf(speedbuf, "%d", comc_curspeed);
unsetenv("comconsole_speed");
env_setenv("comconsole_speed", EV_VOLATILE, speedbuf, comc_speed_set,
env_nounset);
}
}
static int
comc_init(int arg)
{
if (comc_started && arg == 0)
return 0;
comc_started = 1;
comc_setup(comc_curspeed);
return(0);
}
static void
comc_putchar(int c)
{
int wait;
for (wait = COMC_TXWAIT; wait > 0; wait--)
if (inb(COMPORT + com_lsr) & LSR_TXRDY) {
outb(COMPORT + com_data, (u_char)c);
break;
}
}
static int
comc_getchar(void)
{
return(comc_ischar() ? inb(COMPORT + com_data) : -1);
}
static int
comc_ischar(void)
{
return(inb(COMPORT + com_lsr) & LSR_RXRDY);
}
static int
comc_speed_set(struct env_var *ev, int flags, const void *value)
{
int speed;
if (value == NULL || (speed = comc_parsespeed(value)) <= 0) {
printf("Invalid speed\n");
return (CMD_ERROR);
}
if (comc_started && comc_curspeed != speed)
comc_setup(speed);
env_setenv(ev->ev_name, flags | EV_NOHOOK, value, NULL, NULL);
return (CMD_OK);
}
static void
comc_setup(int speed)
{
comc_curspeed = speed;
outb(COMPORT + com_cfcr, CFCR_DLAB | COMC_FMT);
outb(COMPORT + com_dlbl, COMC_BPS(speed) & 0xff);
outb(COMPORT + com_dlbh, COMC_BPS(speed) >> 8);
outb(COMPORT + com_cfcr, COMC_FMT);
outb(COMPORT + com_mcr, MCR_RTS | MCR_DTR);
do
inb(COMPORT + com_data);
while (inb(COMPORT + com_lsr) & LSR_RXRDY);
}
static int
comc_parsespeed(const char *speedstr)
{
char *p;
int speed;
speed = strtol(speedstr, &p, 0);
if (p == speedstr || *p != '\0' || speed <= 0)
return (-1);
return (speed);
}
static int
comc_getspeed(void)
{
u_int divisor;
u_char dlbh;
u_char dlbl;
u_char cfcr;
cfcr = inb(COMPORT + com_cfcr);
outb(COMPORT + com_cfcr, CFCR_DLAB | cfcr);
dlbl = inb(COMPORT + com_dlbl);
dlbh = inb(COMPORT + com_dlbh);
outb(COMPORT + com_cfcr, cfcr);
divisor = dlbh << 8 | dlbl;
/* XXX there should be more sanity checking. */
if (divisor == 0)
return (COMSPEED);
return (COMC_DIV2BPS(divisor));
}