/* $NetBSD: vga_common.c,v 1.11 2009/02/19 00:39:26 jmcneill Exp $ */
/*
* Copyright (c) 1995, 1996 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or
[email protected]
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vga_common.c,v 1.11 2009/02/19 00:39:26 jmcneill Exp $");
#include <sys/param.h>
#include <sys/device.h>
#include <sys/bus.h>
#include <dev/ic/mc6845reg.h>
#include <dev/ic/pcdisplayvar.h>
#include <dev/ic/vgareg.h>
#include <dev/ic/vgavar.h>
/*
* The following functions implement back-end configuration grabbing
* and attachment.
*/
int
vga_common_probe(bus_space_tag_t iot, bus_space_tag_t memt)
{
bus_space_handle_t ioh_vga, ioh_6845, memh;
u_int8_t regval;
u_int16_t vgadata;
int gotio_vga, gotio_6845, gotmem, mono, rv;
int dispoffset;
gotio_vga = gotio_6845 = gotmem = rv = 0;
if (bus_space_map(iot, 0x3c0, 0x10, 0, &ioh_vga))
goto bad;
gotio_vga = 1;
/* read "misc output register" */
regval = bus_space_read_1(iot, ioh_vga, VGA_MISC_DATAR);
mono = !(regval & 1);
if (bus_space_map(iot, (mono ? 0x3b0 : 0x3d0), 0x10, 0, &ioh_6845))
goto bad;
gotio_6845 = 1;
if (bus_space_map(memt, 0xa0000, 0x20000, 0, &memh))
goto bad;
gotmem = 1;
dispoffset = (mono ? 0x10000 : 0x18000);
vgadata = bus_space_read_2(memt, memh, dispoffset);
bus_space_write_2(memt, memh, dispoffset, 0xa55a);
if (bus_space_read_2(memt, memh, dispoffset) != 0xa55a)
goto bad;
bus_space_write_2(memt, memh, dispoffset, vgadata);
/*
* check if this is really a VGA
* (try to write "Color Select" register as XFree86 does)
* XXX check before if at least EGA?
*/
/* reset state */
(void) bus_space_read_1(iot, ioh_6845, 10);
bus_space_write_1(iot, ioh_vga, VGA_ATC_INDEX,
20 | 0x20); /* colselect | enable */
regval = bus_space_read_1(iot, ioh_vga, VGA_ATC_DATAR);
/* toggle the implemented bits */
bus_space_write_1(iot, ioh_vga, VGA_ATC_DATAW, regval ^ 0x0f);
bus_space_write_1(iot, ioh_vga, VGA_ATC_INDEX, 20 | 0x20);
/* read back */
if (bus_space_read_1(iot, ioh_vga, VGA_ATC_DATAR) != (regval ^ 0x0f))
goto bad;
/* restore contents */
bus_space_write_1(iot, ioh_vga, VGA_ATC_DATAW, regval);
rv = 1;
bad:
if (gotio_vga)
bus_space_unmap(iot, ioh_vga, 0x10);
if (gotio_6845)
bus_space_unmap(iot, ioh_6845, 0x10);
if (gotmem)
bus_space_unmap(memt, memh, 0x20000);
return (rv);
}
