1/* $NetBSD: vga_common.c,v 1.10 2008/04/08 12:07:27 cegger Exp $ */ 2 3/* 4 * Copyright (c) 1995, 1996 Carnegie-Mellon University. 5 * All rights reserved. 6 * 7 * Author: Chris G. Demetriou 8 * 9 * Permission to use, copy, modify and distribute this software and 10 * its documentation is hereby granted, provided that both the copyright 11 * notice and this permission notice appear in all copies of the 12 * software, derivative works or modified versions, and any portions 13 * thereof, and that both notices appear in supporting documentation. 14 * 15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 17 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 18 * 19 * Carnegie Mellon requests users of this software to return to 20 * 21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 22 * School of Computer Science 23 * Carnegie Mellon University 24 * Pittsburgh PA 15213-3890 25 * 26 * any improvements or extensions that they make and grant Carnegie the 27 * rights to redistribute these changes. 28 */ 29 30#include <sys/cdefs.h> 31__KERNEL_RCSID(0, "$NetBSD: vga_common.c,v 1.10 2008/04/08 12:07:27 cegger Exp $"); 32 33#include <sys/param.h> 34#include <sys/device.h> 35#include <sys/bus.h> 36 37#include <dev/ic/mc6845reg.h> 38#include <dev/ic/pcdisplayvar.h> 39#include <dev/ic/vgareg.h> 40#include <dev/ic/vgavar.h> 41 42/* 43 * The following functions implement back-end configuration grabbing 44 * and attachment. 45 */ 46int 47vga_common_probe(bus_space_tag_t iot, bus_space_tag_t memt) 48{ 49 bus_space_handle_t ioh_vga, ioh_6845, memh; 50 u_int8_t regval; 51 u_int16_t vgadata; 52 int gotio_vga, gotio_6845, gotmem, mono, rv; 53 int dispoffset; 54 55 gotio_vga = gotio_6845 = gotmem = rv = 0; 56 57 if (bus_space_map(iot, 0x3c0, 0x10, 0, &ioh_vga)) 58 goto bad; 59 gotio_vga = 1; 60 61 /* read "misc output register" */ 62 regval = bus_space_read_1(iot, ioh_vga, VGA_MISC_DATAR); 63 mono = !(regval & 1); 64 65 if (bus_space_map(iot, (mono ? 0x3b0 : 0x3d0), 0x10, 0, &ioh_6845)) 66 goto bad; 67 gotio_6845 = 1; 68 69 if (bus_space_map(memt, 0xa0000, 0x20000, 0, &memh)) 70 goto bad; 71 gotmem = 1; 72 73 dispoffset = (mono ? 0x10000 : 0x18000); 74 75 vgadata = bus_space_read_2(memt, memh, dispoffset); 76 bus_space_write_2(memt, memh, dispoffset, 0xa55a); 77 if (bus_space_read_2(memt, memh, dispoffset) != 0xa55a) 78 goto bad; 79 bus_space_write_2(memt, memh, dispoffset, vgadata); 80 81 /* 82 * check if this is really a VGA 83 * (try to write "Color Select" register as XFree86 does) 84 * XXX check before if at least EGA? 85 */ 86 /* reset state */ 87 (void) bus_space_read_1(iot, ioh_6845, 10); 88 bus_space_write_1(iot, ioh_vga, VGA_ATC_INDEX, 89 20 | 0x20); /* colselect | enable */ 90 regval = bus_space_read_1(iot, ioh_vga, VGA_ATC_DATAR); 91 /* toggle the implemented bits */ 92 bus_space_write_1(iot, ioh_vga, VGA_ATC_DATAW, regval ^ 0x0f); 93 bus_space_write_1(iot, ioh_vga, VGA_ATC_INDEX, 20 | 0x20); 94 /* read back */ 95 if (bus_space_read_1(iot, ioh_vga, VGA_ATC_DATAR) != (regval ^ 0x0f)) 96 goto bad; 97 /* restore contents */ 98 bus_space_write_1(iot, ioh_vga, VGA_ATC_DATAW, regval); 99 100 rv = 1; 101bad: 102 if (gotio_vga) 103 bus_space_unmap(iot, ioh_vga, 0x10); 104 if (gotio_6845) 105 bus_space_unmap(iot, ioh_6845, 0x10); 106 if (gotmem) 107 bus_space_unmap(memt, memh, 0x20000); 108 109 return (rv); 110} 111