Home | History | Annotate | Line # | Download | only in ic 
      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 (at) 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
     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