sys/boot/pc32/libi386/comconsole.c

   1 /*-
   2  * Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/sys/boot/i386/libi386/comconsole.c,v 1.10 2003/09/16 11:24:23 bde Exp $
  26  * $DragonFly: src/sys/boot/pc32/libi386/comconsole.c,v 1.9 2004/06/27 21:27:36 dillon Exp $
  27  */
  28
  29 #include <stand.h>
  30 #include <bootstrap.h>
  31 #include <machine/cpufunc.h>
  32 #include <dev/serial/ic_layer/ns16550.h>
  33 #include "libi386.h"
  34
  35 #define COMC_FMT        0x3             /* 8N1 */
  36 #define COMC_TXWAIT     0x40000         /* transmit timeout */
  37 #define COMC_BPS(x)     (115200 / (x))  /* speed to DLAB divisor */
  38
  39 #ifndef COMPORT
  40 #define COMPORT         0x3f8
  41 #endif
  42 #ifndef COMSPEED
  43 #define COMSPEED        9600
  44 #endif
  45
  46 static void     comc_probe(struct console *cp);
  47 static int      comc_init(int arg);
  48 static void     comc_putchar(int c);
  49 static int      comc_getchar(void);
  50 static int      comc_ischar(void);
  51
  52 static int      comc_started;
  53
  54 struct console comconsole = {
  55     "comconsole",
  56     "serial port",
  57     0,
  58     comc_probe,
  59     comc_init,
  60     comc_putchar,
  61     comc_getchar,
  62     comc_ischar
  63 };
  64
  65 /*
  66  * Probe for a comconsole.  If the comport is not mapped at boot time (which
  67  * is often true on laptops), don't try to access it.  If we can't clear
  68  * the input fifo, don't try to access it later.
  69  *
  70  * Normally the stage-2 bootloader will do this detection and hand us
  71  * appropriate flags, but some bootloaders (pxe, cdboot) load the loader
  72  * directly so we have to check again here.
  73  */
  74 static void
  75 comc_probe(struct console *cp)
  76 {
  77     int i;
  78
  79     if (inb(COMPORT + com_lsr) == 0xFF)
  80         return;
  81     for (i = 255; i >= 0; --i) {
  82         if (comc_ischar() == 0)
  83             break;
  84         inb(COMPORT + com_data);
  85     }
  86     if (i < 0)
  87         return;
  88     cp->c_flags |= (C_PRESENTIN | C_PRESENTOUT);
  89 }
  90
  91 static int
  92 comc_init(int arg)
  93 {
  94     if (comc_started && arg == 0)
  95         return 0;
  96     comc_started = 1;
  97
  98     outb(COMPORT + com_cfcr, CFCR_DLAB | COMC_FMT);
  99     outb(COMPORT + com_dlbl, COMC_BPS(COMSPEED) & 0xff);
 100     outb(COMPORT + com_dlbh, COMC_BPS(COMSPEED) >> 8);
 101     outb(COMPORT + com_cfcr, COMC_FMT);
 102     outb(COMPORT + com_mcr, MCR_RTS | MCR_DTR);
 103
 104 #if 0
 105     /*
 106      * Enable the FIFO so the serial port output in dual console mode doesn't
 107      * interfere so much with the disk twiddle.
 108      *
 109      * DISABLED - apparently many new laptops implement only the base 8250,
 110      * writing to this port can crash them.
 111      */
 112     outb(COMPORT + com_fifo, FIFO_ENABLE);
 113 #endif
 114
 115     /*
 116      * Give the serial port a little time to settle after asserting RTS and
 117      * DTR, then drain any pending garbage.
 118      */
 119     delay(1000000 / 10);
 120     while (comc_ischar())
 121         inb(COMPORT + com_data);
 122
 123     return(0);
 124 }
 125
 126 static void
 127 comc_putchar(int c)
 128 {
 129     int wait;
 130
 131     for (wait = COMC_TXWAIT; wait > 0; wait--) {
 132         if (inb(COMPORT + com_lsr) & LSR_TXRDY) {
 133             outb(COMPORT + com_data, (u_char)c);
 134             break;
 135         }
 136     }
 137 }
 138
 139 static int
 140 comc_getchar(void)
 141 {
 142     return(comc_ischar() ? inb(COMPORT + com_data) : -1);
 143 }
 144
 145 static int
 146 comc_ischar(void)
 147 {
 148     return(inb(COMPORT + com_lsr) & LSR_RXRDY);
 149 }