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 115200 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 } 150