1 /* $NetBSD: vga_common.c,v 1.11 2009/02/19 00:39:26 jmcneill 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 1.11 2009/02/19 00:39:26 jmcneill 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 */
46 int
vga_common_probe(bus_space_tag_t iot,bus_space_tag_t memt)47 vga_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;
101 bad:
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