sys/dev/ic/vga_common.c

   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  */
  46 int
  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 }