xref: /src/sys/dev/pci/voodoofb.c

/*	$NetBSD: voodoofb.c,v 1.39 2012/03/13 18:40:33 elad Exp $	*/

/*
 * Copyright (c) 2005, 2006 Michael Lorenz
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * A console driver for 3Dfx Voodoo3 graphics boards
 * Thanks to Andreas Drewke (andreas_dr (at) gmx.de) for his Voodoo3 driver for BeOS
 * which I used as reference / documentation
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: voodoofb.c,v 1.39 2012/03/13 18:40:33 elad Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/callout.h>
#include <sys/kauth.h>

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcidevs.h>
#include <dev/pci/pciio.h>
#include <dev/pci/voodoofbreg.h>

#include <dev/wscons/wsdisplayvar.h>
#include <dev/wscons/wsconsio.h>
#include <dev/wsfont/wsfont.h>
#include <dev/rasops/rasops.h>
#include <dev/wscons/wsdisplay_vconsvar.h>
#include <dev/pci/wsdisplay_pci.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/i2c_bitbang.h>
#include <dev/i2c/ddcvar.h>
#include <dev/videomode/videomode.h>
#include <dev/videomode/edidvar.h>
#include <dev/videomode/edidreg.h>

#include "opt_wsemul.h"

struct voodoofb_softc {
	device_t sc_dev;
	pci_chipset_tag_t sc_pc;
	pcitag_t sc_pcitag;
	struct pci_attach_args sc_pa;

	bus_space_tag_t sc_memt;
	bus_space_tag_t sc_iot;
	bus_space_handle_t sc_memh;

	bus_space_tag_t sc_regt;
	bus_space_tag_t sc_ioregt;
	bus_space_handle_t sc_regh;
	bus_space_handle_t sc_ioregh;
	bus_addr_t sc_regs, sc_fb, sc_ioreg;
	bus_size_t sc_regsize, sc_fbsize, sc_ioregsize;

	void *sc_ih;

	size_t sc_memsize;
	int sc_memtype;

	int sc_bits_per_pixel;
	int sc_width, sc_height, sc_linebytes;
	const struct videomode *sc_videomode;

	/* glyph cache */
	long sc_defattr, sc_kernattr;
	uint32_t sc_glyphs_defattr[256];
	uint32_t sc_glyphs_kernattr[256];
	int sc_numglyphs, sc_usedglyphs;
	uint32_t sc_cache;	/* offset where cache starts */
	uint32_t sc_fmt;	/* *fmt register */
	void *sc_font;

	/* i2c stuff */
	struct i2c_controller sc_i2c;
	uint8_t sc_edid_data[128];
	struct edid_info sc_edid_info;
	uint32_t sc_i2creg;

	int sc_mode;
	uint32_t sc_bg;

	u_char sc_cmap_red[256];
	u_char sc_cmap_green[256];
	u_char sc_cmap_blue[256];
	int sc_dacw;

	struct vcons_data vd;
};

struct voodoo_regs {
	uint8_t vr_crtc[31];
	uint8_t vr_graph[9];
	uint8_t vr_attr[21];
	uint8_t vr_seq[5];
};

static struct vcons_screen voodoofb_console_screen;

static int	voodoofb_match(device_t, cfdata_t, void *);
static void	voodoofb_attach(device_t, device_t, void *);

static int	voodoofb_drm_print(void *, const char *);
static int	voodoofb_drm_unmap(struct voodoofb_softc *);
static int	voodoofb_drm_map(struct voodoofb_softc *);

CFATTACH_DECL_NEW(voodoofb, sizeof(struct voodoofb_softc), voodoofb_match,
    voodoofb_attach, NULL, NULL);

static bool	voodoofb_is_console(struct voodoofb_softc *);
static void 	voodoofb_init(struct voodoofb_softc *);

static void	voodoofb_cursor(void *, int, int, int);
static void	voodoofb_putchar(void *, int, int, u_int, long);
static void	voodoofb_putchar_aa(void *, int, int, u_int, long);
static void	voodoofb_copycols(void *, int, int, int, int);
static void	voodoofb_erasecols(void *, int, int, int, long);
static void	voodoofb_copyrows(void *, int, int, int);
static void	voodoofb_eraserows(void *, int, int, long);

#if 0
static int	voodoofb_allocattr(void *, int, int, int, long *);
static void	voodoofb_scroll(void *, void *, int);
static int	voodoofb_load_font(void *, void *, struct wsdisplay_font *);
#endif

static int	voodoofb_putcmap(struct voodoofb_softc *,
			    struct wsdisplay_cmap *);
static int 	voodoofb_getcmap(struct voodoofb_softc *,
			    struct wsdisplay_cmap *);
static int 	voodoofb_putpalreg(struct voodoofb_softc *, uint8_t, uint8_t,
			    uint8_t, uint8_t);
static void	voodoofb_bitblt(struct voodoofb_softc *, int, int, int, int,
			    int, int);
static void	voodoofb_rectfill(struct voodoofb_softc *, int, int, int, int,
			    int);
static void	voodoofb_rectinvert(struct voodoofb_softc *, int, int, int,
			    int);
static void	voodoofb_setup_mono(struct voodoofb_softc *, int, int, int,
			    int, uint32_t, uint32_t);
static void	voodoofb_feed_line(struct voodoofb_softc *, int, uint8_t *);

static void	voodoofb_wait_idle(struct voodoofb_softc *);
static void	voodoofb_init_glyphcache(struct voodoofb_softc *,
			    struct rasops_info *);

#ifdef VOODOOFB_ENABLE_INTR
static int	voodoofb_intr(void *);
#endif

static void	voodoofb_set_videomode(struct voodoofb_softc *,
			    const struct videomode *);

struct wsscreen_descr voodoofb_defaultscreen = {
	"default",
	0, 0,
	NULL,
	8, 16,
	WSSCREEN_WSCOLORS | WSSCREEN_HILIT,
	NULL,
};

const struct wsscreen_descr *_voodoofb_scrlist[] = {
	&voodoofb_defaultscreen,
	/* XXX other formats, graphics screen? */
};

struct wsscreen_list voodoofb_screenlist = {
	sizeof(_voodoofb_scrlist) / sizeof(struct wsscreen_descr *), _voodoofb_scrlist
};

static int	voodoofb_ioctl(void *, void *, u_long, void *, int,
		    struct lwp *);
static paddr_t	voodoofb_mmap(void *, void *, off_t, int);

static void	voodoofb_clearscreen(struct voodoofb_softc *);
static void	voodoofb_init_screen(void *, struct vcons_screen *, int,
			    long *);


struct wsdisplay_accessops voodoofb_accessops = {
	voodoofb_ioctl,
	voodoofb_mmap,
	NULL,
	NULL,
	NULL,
	NULL,	/* load_font */
	NULL,	/* polls */
	NULL,	/* scroll */
};

/* I2C glue */
static int voodoofb_i2c_acquire_bus(void *, int);
static void voodoofb_i2c_release_bus(void *, int);
static int voodoofb_i2c_send_start(void *, int);
static int voodoofb_i2c_send_stop(void *, int);
static int voodoofb_i2c_initiate_xfer(void *, i2c_addr_t, int);
static int voodoofb_i2c_read_byte(void *, uint8_t *, int);
static int voodoofb_i2c_write_byte(void *, uint8_t, int);

/* I2C bitbang glue */
static void voodoofb_i2cbb_set_bits(void *, uint32_t);
static void voodoofb_i2cbb_set_dir(void *, uint32_t);
static uint32_t voodoofb_i2cbb_read(void *);

static void voodoofb_setup_i2c(struct voodoofb_softc *);

static const struct i2c_bitbang_ops voodoofb_i2cbb_ops = {
	voodoofb_i2cbb_set_bits,
	voodoofb_i2cbb_set_dir,
	voodoofb_i2cbb_read,
	{
		VSP_SDA0_IN,
		VSP_SCL0_IN,
		0,
		0
	}
};

extern const u_char rasops_cmap[768];

/*
 * Inline functions for getting access to register aperture.
 */
static inline void
voodoo3_write32(struct voodoofb_softc *sc, uint32_t reg, uint32_t val)
{
	bus_space_write_4(sc->sc_regt, sc->sc_regh, reg, val);
}

static inline void
voodoo3_write32s(struct voodoofb_softc *sc, uint32_t reg, uint32_t val)
{
	bus_space_write_stream_4(sc->sc_regt, sc->sc_regh, reg, val);
}
static inline uint32_t
voodoo3_read32(struct voodoofb_softc *sc, uint32_t reg)
{
	return bus_space_read_4(sc->sc_regt, sc->sc_regh, reg);
}

static inline void
voodoo3_write_crtc(struct voodoofb_softc *sc, uint8_t reg, uint8_t val)
{
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, CRTC_INDEX - 0x300, reg);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, CRTC_DATA - 0x300, val);
}

static inline void
voodoo3_write_seq(struct voodoofb_softc *sc, uint8_t reg, uint8_t val)
{
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, SEQ_INDEX - 0x300, reg);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, SEQ_DATA - 0x300, val);
}

static inline void
voodoo3_write_gra(struct voodoofb_softc *sc, uint8_t reg, uint8_t val)
{
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, GRA_INDEX - 0x300, reg);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, GRA_DATA - 0x300, val);
}

static inline void
voodoo3_write_attr(struct voodoofb_softc *sc, uint8_t reg, uint8_t val)
{
	volatile uint8_t junk;
	uint8_t index;

	junk = bus_space_read_1(sc->sc_ioregt, sc->sc_ioregh, IS1_R - 0x300);
	index = bus_space_read_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, reg);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, val);
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, ATT_IW - 0x300, index);
}

static inline void
vga_outb(struct voodoofb_softc *sc, uint32_t reg,  uint8_t val)
{
	bus_space_write_1(sc->sc_ioregt, sc->sc_ioregh, reg - 0x300, val);
}

/* wait until there's room for len bytes in the FIFO */
static inline void
voodoo3_make_room(struct voodoofb_softc *sc, int len)
{
	while ((voodoo3_read32(sc, STATUS) & 0x1f) < len);
}

static void
voodoofb_wait_idle(struct voodoofb_softc *sc)
{
	int i = 0;

	voodoo3_make_room(sc, 1);
	voodoo3_write32(sc, COMMAND_3D, COMMAND_3D_NOP);

	while (1) {
		i = (voodoo3_read32(sc, STATUS) & STATUS_BUSY) ? 0 : i + 1;
		if(i == 3) break;
	}
}

static int
voodoofb_match(device_t parent, cfdata_t match, void *aux)
{
	struct pci_attach_args *pa = (struct pci_attach_args *)aux;

	if (PCI_CLASS(pa->pa_class) != PCI_CLASS_DISPLAY ||
	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_DISPLAY_VGA)
		return 0;
	if ((PCI_VENDOR(pa->pa_id)==PCI_VENDOR_3DFX) &&
	    (PCI_PRODUCT(pa->pa_id)>=PCI_PRODUCT_3DFX_VOODOO3))
		return 100;
	return 0;
}

static void
voodoofb_attach(device_t parent, device_t self, void *aux)
{
	struct voodoofb_softc *sc = device_private(self);
	struct pci_attach_args *pa = aux;
	struct wsemuldisplaydev_attach_args aa;
	struct rasops_info *ri;
#ifdef VOODOOFB_ENABLE_INTR
	pci_intr_handle_t ih;
	const char *intrstr;
#endif
	ulong defattr;
	int console, width, height, i, j;
	prop_dictionary_t dict;
	int linebytes, depth, flags;
	uint32_t bg, fg, ul;

	sc->sc_dev = self;

	sc->sc_mode = WSDISPLAYIO_MODE_EMUL;
	sc->sc_pc = pa->pa_pc;
	sc->sc_pcitag = pa->pa_tag;
	sc->sc_dacw = -1;
	pci_aprint_devinfo(pa, NULL);

	sc->sc_memt = pa->pa_memt;
	sc->sc_iot = pa->pa_iot;
	sc->sc_pa = *pa;

	/* the framebuffer */
	if (pci_mapreg_info(sc->sc_pc, sc->sc_pcitag, 0x14, PCI_MAPREG_TYPE_MEM,
	    &sc->sc_fb, &sc->sc_fbsize, &flags)) {
		aprint_error_dev(self, "failed to map the frame buffer.\n");
	}
	sc->sc_memsize = sc->sc_fbsize >> 1;	/* VRAM aperture is 2x VRAM */

	/* memory-mapped registers */
	if (pci_mapreg_map(pa, 0x10, PCI_MAPREG_TYPE_MEM, 0,
	    &sc->sc_regt, &sc->sc_regh, &sc->sc_regs, &sc->sc_regsize)) {
		aprint_error_dev(self, "failed to map memory-mapped registers.\n");
	}

	/* IO-mapped registers */
	if (pci_mapreg_map(pa, 0x18, PCI_MAPREG_TYPE_IO, 0,
	    &sc->sc_ioregt, &sc->sc_ioregh, &sc->sc_ioreg,
	    &sc->sc_ioregsize)) {
		aprint_error_dev(self, "failed to map IO-mapped registers.\n");
	}
	voodoofb_init(sc);

	/* we should read these from the chip instead of depending on OF */
	width = height = -1;

	dict = device_properties(self);
	if (!prop_dictionary_get_uint32(dict, "width", &width)) {
		aprint_error_dev(self, "no width property\n");
		return;
	}
	if (!prop_dictionary_get_uint32(dict, "height", &height)) {
		aprint_error_dev(self, "no height property\n");
		return;
	}
	if (!prop_dictionary_get_uint32(dict, "depth", &depth)) {
		aprint_error_dev(self, "no depth property\n");
		return;
	}
	linebytes = width;			/* XXX */

	if (width == -1 || height == -1)
		return;

	sc->sc_width = width;
	sc->sc_height = height;
	sc->sc_bits_per_pixel = depth;
	sc->sc_linebytes = linebytes;
	printf("%s: initial resolution %dx%d, %d bit\n", device_xname(self),
	    sc->sc_width, sc->sc_height, sc->sc_bits_per_pixel);

	sc->sc_videomode = NULL;
	voodoofb_setup_i2c(sc);

	/* XXX this should at least be configurable via kernel config */
	if (sc->sc_videomode == NULL) {
		sc->sc_videomode = pick_mode_by_ref(width, height, 60);
	}

	voodoofb_set_videomode(sc, sc->sc_videomode);

	sc->sc_font = NULL;

	vcons_init(&sc->vd, sc, &voodoofb_defaultscreen, &voodoofb_accessops);
	sc->vd.init_screen = voodoofb_init_screen;

	console = voodoofb_is_console(sc);

	ri = &voodoofb_console_screen.scr_ri;
	if (console) {
		vcons_init_screen(&sc->vd, &voodoofb_console_screen, 1,
		    &defattr);
		voodoofb_console_screen.scr_flags |= VCONS_SCREEN_IS_STATIC;

		voodoofb_defaultscreen.textops = &ri->ri_ops;
		voodoofb_defaultscreen.capabilities = ri->ri_caps;
		voodoofb_defaultscreen.nrows = ri->ri_rows;
		voodoofb_defaultscreen.ncols = ri->ri_cols;
		wsdisplay_cnattach(&voodoofb_defaultscreen, ri, 0, 0, defattr);
	} else {
		/*
		 * since we're not the console we can postpone the rest
		 * until someone actually allocates a screen for us
		 */
		voodoofb_set_videomode(sc, sc->sc_videomode);
	}

	printf("%s: %d MB aperture at 0x%08x, %d MB registers at 0x%08x\n",
	    device_xname(self), (u_int)(sc->sc_fbsize >> 20),
	    (u_int)sc->sc_fb, (u_int)(sc->sc_regsize >> 20),
	    (u_int)sc->sc_regs);
#ifdef VOODOOFB_DEBUG
	printf("fb: %08lx\n", (ulong)ri->ri_bits);
#endif

	j = 0;
	if (sc->sc_bits_per_pixel == 8) {
		uint8_t tmp;
		for (i = 0; i < 256; i++) {
			tmp = i & 0xe0;
			/*
			 * replicate bits so 0xe0 maps to a red value of 0xff
			 * in order to make white look actually white
			 */
			tmp |= (tmp >> 3) | (tmp >> 6);
			sc->sc_cmap_red[i] = tmp;

			tmp = (i & 0x1c) << 3;
			tmp |= (tmp >> 3) | (tmp >> 6);
			sc->sc_cmap_green[i] = tmp;

			tmp = (i & 0x03) << 6;
			tmp |= tmp >> 2;
			tmp |= tmp >> 4;
			sc->sc_cmap_blue[i] = tmp;

			voodoofb_putpalreg(sc, i, sc->sc_cmap_red[i],
			    sc->sc_cmap_green[i], sc->sc_cmap_blue[i]);
		}
	} else {
		/* linear ramp */
		for (i = 0; i < 256; i++) {
			sc->sc_cmap_red[i] = i;
			sc->sc_cmap_green[i] = i;
			sc->sc_cmap_blue[i] = i;

			voodoofb_putpalreg(sc, i, sc->sc_cmap_red[i],
			    sc->sc_cmap_green[i], sc->sc_cmap_blue[i]);
		}
	}

#ifdef VOODOOFB_ENABLE_INTR
	/* Interrupt. We don't use it for anything yet */
	if (pci_intr_map(pa, &ih)) {
		aprint_error_dev(self, "failed to map interrupt\n");
		return;
	}

	intrstr = pci_intr_string(sc->sc_pc, ih);
	sc->sc_ih = pci_intr_establish(sc->sc_pc, ih, IPL_NET, voodoofb_intr,
	    sc);
	if (sc->sc_ih == NULL) {
		aprint_error_dev(self, "failed to establish interrupt");
		if (intrstr != NULL)
			aprint_error(" at %s", intrstr);
		aprint_error("\n");
		return;
	}
	aprint_normal_dev(self, "interrupting at %s\n", intrstr);
#endif

	rasops_unpack_attr(defattr, &fg, &bg, &ul);
	sc->sc_bg = ri->ri_devcmap[bg];
	voodoofb_clearscreen(sc);

	if (console)
		vcons_replay_msgbuf(&voodoofb_console_screen);
	aa.console = console;
	aa.scrdata = &voodoofb_screenlist;
	aa.accessops = &voodoofb_accessops;
	aa.accesscookie = &sc->vd;

	config_found(self, &aa, wsemuldisplaydevprint);
	config_found_ia(self, "drm", aux, voodoofb_drm_print);
}

static int
voodoofb_drm_print(void *opaque, const char *pnp)
{
	if (pnp)
		aprint_normal("drm at %s", pnp);

	return UNCONF;
}

static int
voodoofb_drm_unmap(struct voodoofb_softc *sc)
{
	printf("%s: releasing bus resources\n", device_xname(sc->sc_dev));

	bus_space_unmap(sc->sc_ioregt, sc->sc_ioregh, sc->sc_ioregsize);
	bus_space_unmap(sc->sc_regt, sc->sc_regh, sc->sc_regsize);

	return 0;
}

static int
voodoofb_drm_map(struct voodoofb_softc *sc)
{

	/* memory-mapped registers */
	if (pci_mapreg_map(&sc->sc_pa, 0x10, PCI_MAPREG_TYPE_MEM, 0,
	    &sc->sc_regt, &sc->sc_regh, &sc->sc_regs, &sc->sc_regsize)) {
		aprint_error_dev(sc->sc_dev, "failed to map memory-mapped registers.\n");
	}

	/* IO-mapped registers */
	if (pci_mapreg_map(&sc->sc_pa, 0x18, PCI_MAPREG_TYPE_IO, 0,
	    &sc->sc_ioregt, &sc->sc_ioregh, &sc->sc_ioreg,
	    &sc->sc_ioregsize)) {
		aprint_error_dev(sc->sc_dev, "failed to map IO-mapped registers.\n");
	}

	voodoofb_init(sc);
	/* XXX this should at least be configurable via kernel config */
	voodoofb_set_videomode(sc, sc->sc_videomode);

	return 0;
}

static int
voodoofb_putpalreg(struct voodoofb_softc *sc, uint8_t index, uint8_t r,
    uint8_t g, uint8_t b)
{
	uint32_t color;

	sc->sc_cmap_red[index] = r;
	sc->sc_cmap_green[index] = g;
	sc->sc_cmap_blue[index] = b;

	color = (r << 16) | (g << 8) | b;
	voodoo3_make_room(sc, 2);
	voodoo3_write32(sc, DACADDR, index);
	voodoo3_write32(sc, DACDATA, color);

	return 0;
}

static int
voodoofb_putcmap(struct voodoofb_softc *sc, struct wsdisplay_cmap *cm)
{
	u_char *r, *g, *b;
	u_int index = cm->index;
	u_int count = cm->count;
	int i, error;
	u_char rbuf[256], gbuf[256], bbuf[256];

#ifdef VOODOOFB_DEBUG
	printf("putcmap: %d %d\n",index, count);
#endif
	if (cm->index >= 256 || cm->count > 256 ||
	    (cm->index + cm->count) > 256)
		return EINVAL;
	error = copyin(cm->red, &rbuf[index], count);
	if (error)
		return error;
	error = copyin(cm->green, &gbuf[index], count);
	if (error)
		return error;
	error = copyin(cm->blue, &bbuf[index], count);
	if (error)
		return error;

	memcpy(&sc->sc_cmap_red[index], &rbuf[index], count);
	memcpy(&sc->sc_cmap_green[index], &gbuf[index], count);
	memcpy(&sc->sc_cmap_blue[index], &bbuf[index], count);

	r = &sc->sc_cmap_red[index];
	g = &sc->sc_cmap_green[index];
	b = &sc->sc_cmap_blue[index];

	for (i = 0; i < count; i++) {
		voodoofb_putpalreg(sc, index, *r, *g, *b);
		index++;
		r++, g++, b++;
	}
	return 0;
}

static int
voodoofb_getcmap(struct voodoofb_softc *sc, struct wsdisplay_cmap *cm)
{
	u_int index = cm->index;
	u_int count = cm->count;
	int error;

	if (index >= 255 || count > 256 || index + count > 256)
		return EINVAL;

	error = copyout(&sc->sc_cmap_red[index],   cm->red,   count);
	if (error)
		return error;
	error = copyout(&sc->sc_cmap_green[index], cm->green, count);
	if (error)
		return error;
	error = copyout(&sc->sc_cmap_blue[index],  cm->blue,  count);
	if (error)
		return error;

	return 0;
}

static bool
voodoofb_is_console(struct voodoofb_softc *sc)
{
	prop_dictionary_t dict;
	bool console;

	dict = device_properties(sc->sc_dev);
	prop_dictionary_get_bool(dict, "is_console", &console);
	return console;
}

static void
voodoofb_clearscreen(struct voodoofb_softc *sc)
{
	voodoofb_rectfill(sc, 0, 0, sc->sc_width, sc->sc_height, sc->sc_bg);
}

/*
 * wsdisplay_emulops
 */

static void
voodoofb_cursor(void *cookie, int on, int row, int col)
{
	struct rasops_info *ri = cookie;
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	int x, y, wi, he;

	wi = ri->ri_font->fontwidth;
	he = ri->ri_font->fontheight;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		x = ri->ri_ccol * wi + ri->ri_xorigin;
		y = ri->ri_crow * he + ri->ri_yorigin;
		if (ri->ri_flg & RI_CURSOR) {
			voodoofb_rectinvert(sc, x, y, wi, he);
			ri->ri_flg &= ~RI_CURSOR;
		}
		ri->ri_crow = row;
		ri->ri_ccol = col;
		if (on)
		{
			x = ri->ri_ccol * wi + ri->ri_xorigin;
			y = ri->ri_crow * he + ri->ri_yorigin;
			voodoofb_rectinvert(sc, x, y, wi, he);
			ri->ri_flg |= RI_CURSOR;
		}
	} else {
		ri->ri_flg &= ~RI_CURSOR;
		ri->ri_crow = row;
		ri->ri_ccol = col;
	}
}

#if 0
int
voodoofb_mapchar(void *cookie, int uni, u_int *index)
{
	return 0;
}
#endif

static void
voodoofb_putchar(void *cookie, int row, int col, u_int c, long attr)
{
	struct rasops_info *ri = cookie;
	struct wsdisplay_font *font = PICK_FONT(ri, c);
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		uint8_t *data;
		int fg, bg, uc, i;
		int x, y, wi, he;

		wi = font->fontwidth;
		he = font->fontheight;

		if (!CHAR_IN_FONT(c, font))
			return;
		bg = (u_char)ri->ri_devcmap[(attr >> 16) & 0xf];
		fg = (u_char)ri->ri_devcmap[(attr >> 24) & 0xf];
		x = ri->ri_xorigin + col * wi;
		y = ri->ri_yorigin + row * he;
		if (c == 0x20) {
			voodoofb_rectfill(sc, x, y, wi, he, bg);
		} else {
			uc = c - font->firstchar;
			data = (uint8_t *)font->data + uc *
			    ri->ri_fontscale;
				voodoofb_setup_mono(sc, x, y, wi, he, fg, bg);
			for (i = 0; i < he; i++) {
				voodoofb_feed_line(sc, font->stride, data);
				data += font->stride;
			}
		}
	}
}

static void
voodoofb_putchar_aa(void *cookie, int row, int col, u_int c, long attr)
{
	struct rasops_info *ri = cookie;
	struct wsdisplay_font *font = PICK_FONT(ri, c);
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	uint8_t *data;
	uint32_t bg, latch = 0, bg8, fg8, pixel, save_offset = 0;
	int i, x, y, wi, he, r, g, b, aval;
	int r1, g1, b1, r0, g0, b0, fgo, bgo, j;

	if (sc->sc_mode != WSDISPLAYIO_MODE_EMUL)
		return;

	if (!CHAR_IN_FONT(c, font))
		return;

	wi = font->fontwidth;
	he = font->fontheight;

	bg = ri->ri_devcmap[(attr >> 16) & 0xf];
	x = ri->ri_xorigin + col * wi;
	y = ri->ri_yorigin + row * he;
	if (c == 0x20) {
		voodoofb_rectfill(sc, x, y, wi, he, bg);
		return;
	}

	/* first, see if it's in the cache */
	if ((attr == sc->sc_defattr) && (c < 256)) {
		uint32_t offset = sc->sc_glyphs_defattr[c];
		if (offset != 0) {
			voodoo3_make_room(sc, 8);
			voodoo3_write32(sc, SRCBASE, offset);
			voodoo3_write32(sc, DSTBASE, 0);
			voodoo3_write32(sc, SRCFORMAT,	sc->sc_fmt);
			voodoo3_write32(sc, DSTFORMAT,	sc->sc_linebytes | FMT_8BIT);
			voodoo3_write32(sc, DSTSIZE,	wi | (he << 16));
			voodoo3_write32(sc, DSTXY,	x | (y << 16));
			voodoo3_write32(sc, SRCXY,	0);
			voodoo3_write32(sc, COMMAND_2D, COMMAND_2D_S2S_BITBLT |
			    (ROP_COPY << 24) | SST_2D_GO);
			return;
		} else {
			int slot = sc->sc_usedglyphs;
			sc->sc_usedglyphs++;
			save_offset = sc->sc_cache + (slot * ri->ri_fontscale);
			sc->sc_glyphs_defattr[c] = save_offset;
		}
	}
	data = WSFONT_GLYPH(c, font);

	voodoo3_make_room(sc, 7);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, SRCFORMAT,	FMT_8BIT | FMT_PAD_BYTE);
	voodoo3_write32(sc, DSTFORMAT,	sc->sc_linebytes | FMT_8BIT);
	voodoo3_write32(sc, DSTSIZE,	wi | (he << 16));
	voodoo3_write32(sc, DSTXY,	x | (y << 16));
	voodoo3_write32(sc, SRCXY,	0);
	voodoo3_write32(sc, COMMAND_2D, COMMAND_2D_H2S_BITBLT |
	    (ROP_COPY << 24) | SST_2D_GO);

	/*
	 * we need the RGB colours here, so get offsets into rasops_cmap
	 */
	fgo = ((attr >> 24) & 0xf) * 3;
	bgo = ((attr >> 16) & 0xf) * 3;

	r0 = rasops_cmap[bgo];
	r1 = rasops_cmap[fgo];
	g0 = rasops_cmap[bgo + 1];
	g1 = rasops_cmap[fgo + 1];
	b0 = rasops_cmap[bgo + 2];
	b1 = rasops_cmap[fgo + 2];
#define R3G3B2(r, g, b) ((r & 0xe0) | ((g >> 3) & 0x1c) | (b >> 6))
	bg8 = R3G3B2(r0, g0, b0);
	fg8 = R3G3B2(r1, g1, b1);
	voodoo3_make_room(sc, 15);
	j = 15;
	for (i = 0; i < ri->ri_fontscale; i++) {
		aval = *data;
		if (aval == 0) {
			pixel = bg8;
		} else if (aval == 255) {
			pixel = fg8;
		} else {
			r = aval * r1 + (255 - aval) * r0;
			g = aval * g1 + (255 - aval) * g0;
			b = aval * b1 + (255 - aval) * b0;
			pixel = ((r & 0xe000) >> 8) |
				((g & 0xe000) >> 11) |
				((b & 0xc000) >> 14);
		}
		latch = (latch << 8) | pixel;
		/* write in 32bit chunks */
		if ((i & 3) == 3) {
			voodoo3_write32s(sc, LAUNCH_2D, latch);
			/*
			 * not strictly necessary, old data should be shifted
			 * out
			 */
			latch = 0;
			/*
			 * check for pipeline space every now and then
			 * I don't think we can feed a Voodoo3 faster than it
			 * can process simple pixel data but I have been wrong
			 * about that before
			 */
			j--;
			if (j == 0) {
				voodoo3_make_room(sc, 15);
				j = 15;
			}
		}
		data++;
	}
	/* if we have pixels left in latch write them out */
	if ((i & 3) != 0) {
		latch = latch << ((4 - (i & 3)) << 3);
		voodoo3_write32s(sc, LAUNCH_2D, latch);
	}
	if (save_offset != 0) {
		/* save the glyph we just drew */
		voodoo3_make_room(sc, 8);
		voodoo3_write32(sc, SRCBASE, 0);
		voodoo3_write32(sc, DSTBASE, save_offset);
		voodoo3_write32(sc, SRCFORMAT,	sc->sc_linebytes | FMT_8BIT);
		voodoo3_write32(sc, DSTFORMAT,	sc->sc_fmt);
		voodoo3_write32(sc, DSTSIZE,	wi | (he << 16));
		voodoo3_write32(sc, DSTXY,	0);
		voodoo3_write32(sc, SRCXY,	x | (y << 16));
		voodoo3_write32(sc, COMMAND_2D, COMMAND_2D_S2S_BITBLT |
			    (ROP_COPY << 24) | SST_2D_GO);
	}
}

static void
voodoofb_copycols(void *cookie, int row, int srccol, int dstcol, int ncols)
{
	struct rasops_info *ri = cookie;
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	int32_t xs, xd, y, width, height;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		xs = ri->ri_xorigin + ri->ri_font->fontwidth * srccol;
		xd = ri->ri_xorigin + ri->ri_font->fontwidth * dstcol;
		y = ri->ri_yorigin + ri->ri_font->fontheight * row;
		width = ri->ri_font->fontwidth * ncols;
		height = ri->ri_font->fontheight;
		voodoofb_bitblt(sc, xs, y, xd, y, width, height);
	}
}

static void
voodoofb_erasecols(void *cookie, int row, int startcol, int ncols,
    long fillattr)
{
	struct rasops_info *ri = cookie;
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	int32_t x, y, width, height, fg, bg, ul;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		x = ri->ri_xorigin + ri->ri_font->fontwidth * startcol;
		y = ri->ri_yorigin + ri->ri_font->fontheight * row;
		width = ri->ri_font->fontwidth * ncols;
		height = ri->ri_font->fontheight;
		rasops_unpack_attr(fillattr, &fg, &bg, &ul);

		voodoofb_rectfill(sc, x, y, width, height, ri->ri_devcmap[bg]);
	}
}

static void
voodoofb_copyrows(void *cookie, int srcrow, int dstrow, int nrows)
{
	struct rasops_info *ri = cookie;
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	int32_t x, ys, yd, width, height;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		x = ri->ri_xorigin;
		ys = ri->ri_yorigin + ri->ri_font->fontheight * srcrow;
		yd = ri->ri_yorigin + ri->ri_font->fontheight * dstrow;
		width = ri->ri_emuwidth;
		height = ri->ri_font->fontheight * nrows;
		voodoofb_bitblt(sc, x, ys, x, yd, width, height);
	}
}

static void
voodoofb_eraserows(void *cookie, int row, int nrows, long fillattr)
{
	struct rasops_info *ri = cookie;
	struct vcons_screen *scr = ri->ri_hw;
	struct voodoofb_softc *sc = scr->scr_cookie;
	int32_t x, y, width, height, fg, bg, ul;

	if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
		rasops_unpack_attr(fillattr, &fg, &bg, &ul);
		if ((row == 0) && (nrows == ri->ri_rows)) {
			/* clear the whole screen */
			voodoofb_rectfill(sc, 0, 0, ri->ri_width,
			    ri->ri_height, ri->ri_devcmap[bg]);
		} else {
			x = ri->ri_xorigin;
			y = ri->ri_yorigin + ri->ri_font->fontheight * row;
			width = ri->ri_emuwidth;
			height = ri->ri_font->fontheight * nrows;
			voodoofb_rectfill(sc, x, y, width, height,
			    ri->ri_devcmap[bg]);
		}
	}
}

static void
voodoofb_bitblt(struct voodoofb_softc *sc, int xs, int ys, int xd, int yd, int width, int height)
{
	uint32_t fmt, blitcmd;

	fmt = sc->sc_linebytes | ((sc->sc_bits_per_pixel +
	    ((sc->sc_bits_per_pixel == 8) ? 0 : 8)) << 13);
	blitcmd = COMMAND_2D_S2S_BITBLT | (ROP_COPY << 24);

	if (xs <= xd) {
	        blitcmd |= BIT(14);
		xs += (width - 1);
		xd += (width - 1);
	}
	if (ys <= yd) {
		blitcmd |= BIT(15);
		ys += (height - 1);
		yd += (height - 1);
	}
	voodoo3_make_room(sc, 8);

	voodoo3_write32(sc, SRCBASE, 0);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, SRCFORMAT, fmt);
	voodoo3_write32(sc, DSTFORMAT, fmt);
	voodoo3_write32(sc, DSTSIZE,   width | (height << 16));
	voodoo3_write32(sc, DSTXY,     xd | (yd << 16));
	voodoo3_write32(sc, SRCXY, xs | (ys << 16));
	voodoo3_write32(sc, COMMAND_2D, blitcmd | SST_2D_GO);
}

static void
voodoofb_rectfill(struct voodoofb_softc *sc, int x, int y, int width,
    int height, int colour)
{
	uint32_t fmt, col;

	col = (colour << 24) | (colour << 16) | (colour << 8) | colour;
	fmt = sc->sc_linebytes | ((sc->sc_bits_per_pixel +
	    ((sc->sc_bits_per_pixel == 8) ? 0 : 8)) << 13);

	voodoo3_make_room(sc, 7);
	voodoo3_write32(sc, DSTFORMAT, fmt);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, COLORFORE, colour);
	voodoo3_write32(sc, COLORBACK, colour);
	voodoo3_write32(sc, COMMAND_2D, COMMAND_2D_FILLRECT | (ROP_COPY << 24));
	voodoo3_write32(sc, DSTSIZE,    width | (height << 16));
	voodoo3_write32(sc, LAUNCH_2D,  x | (y << 16));
}

static void
voodoofb_rectinvert(struct voodoofb_softc *sc, int x, int y, int width,
    int height)
{
	uint32_t fmt;

	fmt = sc->sc_linebytes | ((sc->sc_bits_per_pixel +
	    ((sc->sc_bits_per_pixel == 8) ? 0 : 8)) << 13);

	voodoo3_make_room(sc, 8);
	voodoo3_write32(sc, SRCBASE, 0);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, DSTFORMAT,	fmt);
	voodoo3_write32(sc, COMMAND_2D,	COMMAND_2D_FILLRECT |
	    (ROP_INVERT << 24));
	voodoo3_write32(sc, DSTSIZE,	width | (height << 16));
	voodoo3_write32(sc, DSTXY,	x | (y << 16));
	voodoo3_write32(sc, LAUNCH_2D,	x | (y << 16));
}

static void
voodoofb_setup_mono(struct voodoofb_softc *sc, int xd, int yd, int width, int height, uint32_t fg,
					uint32_t bg)
{
	uint32_t dfmt, sfmt = sc->sc_linebytes;

	dfmt = sc->sc_linebytes | ((sc->sc_bits_per_pixel +
	    ((sc->sc_bits_per_pixel == 8) ? 0 : 8)) << 13);

	voodoo3_make_room(sc, 10);
	voodoo3_write32(sc, SRCFORMAT,	sfmt);
	voodoo3_write32(sc, DSTFORMAT,	dfmt);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, COLORFORE,	fg);
	voodoo3_write32(sc, COLORBACK,	bg);
	voodoo3_write32(sc, DSTSIZE,	width | (height << 16));
	voodoo3_write32(sc, DSTXY,	xd | (yd << 16));
	voodoo3_write32(sc, SRCXY,	0);
	voodoo3_write32(sc, COMMAND_2D, COMMAND_2D_H2S_BITBLT |
	    (ROP_COPY << 24) | SST_2D_GO);

	/* now feed the data into the chip */
}

static void
voodoofb_feed_line(struct voodoofb_softc *sc, int count, uint8_t *data)
{
	int i;
	uint32_t latch = 0, bork;
	int shift = 0;

	voodoo3_make_room(sc, count);
	for (i = 0; i < count; i++) {
		bork = data[i];
		latch |= (bork << shift);
		if (shift == 24) {
			voodoo3_write32(sc, LAUNCH_2D, latch);
			latch = 0;
			shift = 0;
		} else
			shift += 8;
		}
	if (shift != 24)
		voodoo3_write32(sc, LAUNCH_2D, latch);
}

#if 0
static int
voodoofb_allocattr(void *cookie, int fg, int bg, int flags, long *attrp)
{

	return 0;
}
#endif

/*
 * wsdisplay_accessops
 */

static int
voodoofb_ioctl(void *v, void *vs, u_long cmd, void *data, int flag,
	struct lwp *l)
{
	struct vcons_data *vd = v;
	struct voodoofb_softc *sc = vd->cookie;
	struct wsdisplay_fbinfo *wdf;
	struct vcons_screen *ms = vd->active;

	switch (cmd) {
	case WSDISPLAYIO_GTYPE:
		*(u_int *)data = WSDISPLAY_TYPE_PCIMISC;
		return 0;

	case WSDISPLAYIO_GINFO:
		wdf = (void *)data;
		wdf->height = ms->scr_ri.ri_height;
		wdf->width = ms->scr_ri.ri_width;
		wdf->depth = ms->scr_ri.ri_depth;
		wdf->cmsize = 256;
		return 0;

	case WSDISPLAYIO_GETCMAP:
		return voodoofb_getcmap(sc,
		    (struct wsdisplay_cmap *)data);

	case WSDISPLAYIO_PUTCMAP:
		return voodoofb_putcmap(sc,
		    (struct wsdisplay_cmap *)data);

	/* PCI config read/write passthrough. */
	case PCI_IOC_CFGREAD:
	case PCI_IOC_CFGWRITE:
		return pci_devioctl(sc->sc_pc, sc->sc_pcitag,
		    cmd, data, flag, l);

	case WSDISPLAYIO_GET_BUSID:
		return wsdisplayio_busid_pci(sc->sc_dev, sc->sc_pc,
		    sc->sc_pcitag, data);

	case WSDISPLAYIO_SMODE: {
		int new_mode = *(int*)data;
		if (new_mode != sc->sc_mode) {
			sc->sc_mode = new_mode;
			if (new_mode == WSDISPLAYIO_MODE_EMUL) {
				voodoofb_drm_map(sc);
				int i;

				/* restore the palette */
				for (i = 0; i < 256; i++) {
					voodoofb_putpalreg(sc,
					   i,
					   sc->sc_cmap_red[i],
					   sc->sc_cmap_green[i],
					   sc->sc_cmap_blue[i]);
				}
				voodoofb_clearscreen(sc);
				vcons_redraw_screen(ms);
			} else {
				voodoofb_drm_unmap(sc);
			}
		}
		}
		return 0;
	}
	return EPASSTHROUGH;
}

static paddr_t
voodoofb_mmap(void *v, void *vs, off_t offset, int prot)
{
	struct vcons_data *vd = v;
	struct voodoofb_softc *sc = vd->cookie;
	paddr_t pa;

	/* 'regular' framebuffer mmap()ing */
	if (offset < sc->sc_fbsize) {
		pa = bus_space_mmap(sc->sc_memt, offset, 0, prot,
		    BUS_SPACE_MAP_LINEAR);
		return pa;
	}

	/*
	 * restrict all other mappings to processes with superuser privileges
	 * or the kernel itself
	 */
	if (kauth_authorize_machdep(kauth_cred_get(), KAUTH_MACHDEP_UNMANAGEDMEM,
	    NULL, NULL, NULL, NULL) != 0) {
		aprint_error_dev(sc->sc_dev, "mmap() rejected.\n");
		return -1;
	}

	if ((offset >= sc->sc_fb) && (offset < (sc->sc_fb + sc->sc_fbsize))) {
		pa = bus_space_mmap(sc->sc_memt, offset, 0, prot,
		    BUS_SPACE_MAP_LINEAR);
		return pa;
	}

	if ((offset >= sc->sc_regs) && (offset < (sc->sc_regs +
	    sc->sc_regsize))) {
		pa = bus_space_mmap(sc->sc_memt, offset, 0, prot,
		    BUS_SPACE_MAP_LINEAR);
		return pa;
	}

#ifdef PCI_MAGIC_IO_RANGE
	/* allow mapping of IO space */
	if ((offset >= PCI_MAGIC_IO_RANGE) &&\
	    (offset < PCI_MAGIC_IO_RANGE + 0x10000)) {
		pa = bus_space_mmap(sc->sc_iot, offset - PCI_MAGIC_IO_RANGE,
		    0, prot, BUS_SPACE_MAP_LINEAR);
		return pa;
	}
#endif

#ifdef OFB_ALLOW_OTHERS
	if (offset >= 0x80000000) {
		pa = bus_space_mmap(sc->sc_memt, offset, 0, prot,
		    BUS_SPACE_MAP_LINEAR);
		return pa;
	}
#endif
	return -1;
}

static void
voodoofb_init_screen(void *cookie, struct vcons_screen *scr,
    int existing, long *defattr)
{
	struct voodoofb_softc *sc = cookie;
	struct rasops_info *ri = &scr->scr_ri;

	ri->ri_depth = sc->sc_bits_per_pixel;
	ri->ri_width = sc->sc_width;
	ri->ri_height = sc->sc_height;
	ri->ri_stride = sc->sc_linebytes;
	ri->ri_flg = RI_CENTER | RI_8BIT_IS_RGB | RI_ENABLE_ALPHA;

	rasops_init(ri, 0, 0);
	ri->ri_caps = WSSCREEN_WSCOLORS;

	rasops_reconfig(ri, sc->sc_height / ri->ri_font->fontheight,
		    sc->sc_width / ri->ri_font->fontwidth);

	ri->ri_hw = scr;
	ri->ri_ops.copyrows = voodoofb_copyrows;
	ri->ri_ops.copycols = voodoofb_copycols;
	ri->ri_ops.eraserows = voodoofb_eraserows;
	ri->ri_ops.erasecols = voodoofb_erasecols;
	ri->ri_ops.cursor = voodoofb_cursor;
	if (FONT_IS_ALPHA(ri->ri_font)) {
		ri->ri_ops.putchar = voodoofb_putchar_aa;
		ri->ri_ops.allocattr(ri, WS_DEFAULT_FG, WS_DEFAULT_BG,
		     0, &sc->sc_defattr);
		sc->sc_kernattr = (WS_KERNEL_FG << 24) | (WS_KERNEL_BG << 16);
		voodoofb_init_glyphcache(sc, ri);
	} else {
		ri->ri_ops.putchar = voodoofb_putchar;
	}
}

#if 0
int
voodoofb_load_font(void *v, void *cookie, struct wsdisplay_font *data)
{

	return 0;
}
#endif

#ifdef VOODOOFB_ENABLE_INTR
static int
voodoofb_intr(void *arg)
{
	struct voodoofb_softc *sc = arg;

	voodoo3_write32(sc, V3_STATUS, 0);	/* clear interrupts */
	return 1;
}
#endif

/* video mode stuff */

#define REFFREQ 14318	/* .18 */

#define ABS(a) ((a < 0) ? -a : a)

static int
voodoofb_calc_pll(int freq, int *f_out, int isBanshee)
{
	int m, n, k, best_m, best_n, best_k, f_cur, best_error;
	int minm, maxm;

	best_error = freq;
	best_n = best_m = best_k = 0;

	if (isBanshee) {
		minm = 24;
		maxm = 24;
	} else {
		minm = 1;
		maxm = 57;
		/* This used to be 64, alas it seems the last 8 (funny that ?)
		 * values cause jittering at lower resolutions. I've not done
		 * any calculations to what the adjustment affects clock ranges,
		 * but I can still run at 1600x1200@75Hz */
	}
	for (n = 1; n < 256; n++) {
		f_cur = REFFREQ * (n + 2);
		if (f_cur < freq) {
			f_cur = f_cur / 3;
			if (freq - f_cur < best_error) {
				best_error = freq - f_cur;
				best_n = n;
				best_m = 1;
				best_k = 0;
				continue;
      			}
		}
		for (m = minm; m < maxm; m++) {
			for (k = 0; k < 4; k++) {
				f_cur = REFFREQ * (n + 2) / (m + 2) / (1 << k);
				if (ABS(f_cur - freq) < best_error) {
					best_error = ABS(f_cur - freq);
					best_n = n;
					best_m = m;
					best_k = k;
				}
			}
		}
	}
	n = best_n;
	m = best_m;
	k = best_k;
	*f_out = REFFREQ * (n + 2) / (m + 2) / (1 << k);
	return ( n << 8) | (m << 2) | k;
}

static void
voodoofb_setup_monitor(struct voodoofb_softc *sc, const struct videomode *vm)
{
	struct voodoo_regs mod;
	struct voodoo_regs *mode;
	uint32_t horizontal_display_end, horizontal_sync_start,
		horizontal_sync_end, horizontal_total,
		horizontal_blanking_start, horizontal_blanking_end;

	uint32_t vertical_display_enable_end, vertical_sync_start,
		vertical_sync_end, vertical_total, vertical_blanking_start,
		vertical_blanking_end;

	uint32_t wd; // CRTC offset

	int i;

	uint8_t misc;

	memset(&mod, 0, sizeof(mode));

	mode = &mod;

	wd = (vm->hdisplay >> 3) - 1;
	horizontal_display_end	= (vm->hdisplay >> 3) - 1;
	horizontal_sync_start	= (vm->hsync_start >> 3) - 1;
	horizontal_sync_end	= (vm->hsync_end >> 3) - 1;
	horizontal_total  	= (vm->htotal   >> 3) - 1;
	horizontal_blanking_start = horizontal_display_end;
	horizontal_blanking_end = horizontal_total;

	vertical_display_enable_end  = vm->vdisplay - 1;
	vertical_sync_start  	= vm->vsync_start;	// - 1;
	vertical_sync_end	= vm->vsync_end;	// - 1;
	vertical_total		= vm->vtotal - 2;
	vertical_blanking_start	= vertical_display_enable_end;
	vertical_blanking_end	= vertical_total;

#if 0
	misc = 0x0f |
	    (vm->hdisplay < 400 ? 0xa0 :
		vm->hdisplay < 480 ? 0x60 :
		vm->hdisplay < 768 ? 0xe0 : 0x20);
#else
	misc = 0x2f;
	if (vm->flags & VID_NHSYNC)
		misc |= HSYNC_NEG;
	if (vm->flags & VID_NVSYNC)
		misc |= VSYNC_NEG;
#ifdef VOODOOFB_DEBUG
	printf("misc: %02x\n", misc);
#endif
#endif
	mode->vr_seq[0] = 3;
	mode->vr_seq[1] = 1;
	mode->vr_seq[2] = 8;
	mode->vr_seq[3] = 0;
	mode->vr_seq[4] = 6;

	/* crtc regs start */
	mode->vr_crtc[0] = horizontal_total - 4;
	mode->vr_crtc[1] = horizontal_display_end;
	mode->vr_crtc[2] = horizontal_blanking_start;
	mode->vr_crtc[3] = 0x80 | (horizontal_blanking_end & 0x1f);
	mode->vr_crtc[4] = horizontal_sync_start;

	mode->vr_crtc[5] = ((horizontal_blanking_end & 0x20) << 2) |
	    (horizontal_sync_end & 0x1f);
	mode->vr_crtc[6] = vertical_total;
	mode->vr_crtc[7] = ((vertical_sync_start & 0x200) >> 2) |
	    ((vertical_display_enable_end & 0x200) >> 3) |
	    ((vertical_total & 0x200) >> 4) |
	    0x10 |
	    ((vertical_blanking_start & 0x100) >> 5) |
	    ((vertical_sync_start  & 0x100) >> 6) |
	    ((vertical_display_enable_end  & 0x100) >> 7) |
	    ((vertical_total  & 0x100) >> 8);

	mode->vr_crtc[8] = 0;
	mode->vr_crtc[9] = 0x40 |
	    ((vertical_blanking_start & 0x200) >> 4);

	mode->vr_crtc[10] = 0;
	mode->vr_crtc[11] = 0;
	mode->vr_crtc[12] = 0;
	mode->vr_crtc[13] = 0;
	mode->vr_crtc[14] = 0;
	mode->vr_crtc[15] = 0;

	mode->vr_crtc[16] = vertical_sync_start;
	mode->vr_crtc[17] = (vertical_sync_end & 0x0f) | 0x20;
	mode->vr_crtc[18] = vertical_display_enable_end;
	mode->vr_crtc[19] = wd; // CRTC offset
	mode->vr_crtc[20] = 0;
	mode->vr_crtc[21] = vertical_blanking_start;
	mode->vr_crtc[22] = vertical_blanking_end + 1;
	mode->vr_crtc[23] = 128;
	mode->vr_crtc[24] = 255;

	/* overflow registers */
	mode->vr_crtc[CRTC_HDISP_EXT] =
	    (horizontal_total&0x100) >> 8 |
	    (horizontal_display_end & 0x100) >> 6 |
	    (horizontal_blanking_start & 0x100) >> 4 |
	    (horizontal_blanking_end & 0x40) >> 1 |
	    (horizontal_sync_start & 0x100) >> 2 |
	    (horizontal_sync_end & 0x20) << 2;

	mode->vr_crtc[CRTC_VDISP_EXT] =
	    (vertical_total & 0x400) >> 10 |
	    (vertical_display_enable_end & 0x400) >> 8 | /* the manual is contradictory here */
	    (vertical_blanking_start & 0x400) >> 6 |
	    (vertical_blanking_end & 0x400) >> 4;

	/* attr regs start */
	mode->vr_attr[0] = 0;
	mode->vr_attr[1] = 0;
	mode->vr_attr[2] = 0;
	mode->vr_attr[3] = 0;
	mode->vr_attr[4] = 0;
	mode->vr_attr[5] = 0;
	mode->vr_attr[6] = 0;
	mode->vr_attr[7] = 0;
	mode->vr_attr[8] = 0;
	mode->vr_attr[9] = 0;
	mode->vr_attr[10] = 0;
	mode->vr_attr[11] = 0;
	mode->vr_attr[12] = 0;
	mode->vr_attr[13] = 0;
	mode->vr_attr[14] = 0;
	mode->vr_attr[15] = 0;
	mode->vr_attr[16] = 1;
	mode->vr_attr[17] = 0;
	mode->vr_attr[18] = 15;
	mode->vr_attr[19] = 0;
	/* attr regs end */

	/* graph regs start */
	mode->vr_graph[0] = 159;
	mode->vr_graph[1] = 127;
	mode->vr_graph[2] = 127;
	mode->vr_graph[3] = 131;
	mode->vr_graph[4] = 130;
	mode->vr_graph[5] = 142;
	mode->vr_graph[6] = 30;
	mode->vr_graph[7] = 245;
	mode->vr_graph[8] = 0;

	vga_outb(sc, MISC_W, misc | 0x01);

	for(i = 0; i < 5; i++)
		voodoo3_write_seq(sc, i, mode->vr_seq[i]);
	for (i = 0; i < CRTC_PCI_READBACK; i ++)
        	voodoo3_write_crtc(sc, i, mode->vr_crtc[i]);
	for (i = 0; i < 0x14; i ++)
        	voodoo3_write_attr(sc, i, mode->vr_attr[i]);
	for (i = 0; i < 0x09; i ++)
        	voodoo3_write_gra(sc, i, mode->vr_graph[i]);
}

static void
voodoofb_set_videomode(struct voodoofb_softc *sc,
    const struct videomode *vm)
{
	uint32_t miscinit0 = 0;
	int vidpll, fout;
	uint32_t vp, vidproc = VIDPROCDEFAULT;
	uint32_t bpp = 1;	/* for now */
	uint32_t bytes_per_row = vm->hdisplay * bpp;

	sc->sc_bits_per_pixel = bpp << 3;
	sc->sc_width = vm->hdisplay;
	sc->sc_height = vm->vdisplay;
	sc->sc_linebytes = bytes_per_row;

	voodoofb_setup_monitor(sc, vm);
	vp = voodoo3_read32(sc, VIDPROCCFG);

	vidproc &= ~(0x1c0000); /* clear bits 18 to 20, bpp in vidproccfg */
	/* enable bits 18 to 20 to the required bpp */
	vidproc |= ((bpp - 1) << VIDCFG_PIXFMT_SHIFT);

	vidpll = voodoofb_calc_pll(vm->dot_clock, &fout, 0);

#ifdef VOODOOFB_DEBUG
	printf("old vidproc: %08x\n", vp);
	printf("pll: %08x %d\n", vidpll, fout);
#endif
	/* bit 10 of vidproccfg, is enabled or disabled as needed */
	switch (bpp) {
		case 1:
			/*
			 * bit 10 off for palettized modes only, off means
			 * palette is used
			 */
			vidproc &= ~(1 << 10);
			break;
#if 0
		case 2:
			#if __POWERPC__
				miscinit0 = 0xc0000000;
			#endif
			/* bypass palette for 16bit modes */
			vidproc |= (1 << 10);
			break;
		case 4:
			#if __POWERPC__
				miscinit0 = 0x40000000;
			#endif
			vidproc |= (1 << 10); /* Same for 32bit modes */
			break;
#endif
		default:
			printf("We support only 8 bit for now\n");
			return;
	}

	voodoofb_wait_idle(sc);

	voodoo3_write32(sc, MISCINIT1, voodoo3_read32(sc, MISCINIT1) | 0x01);

	voodoo3_make_room(sc, 4);
	voodoo3_write32(sc, VGAINIT0, 4928);
	voodoo3_write32(sc, DACMODE, 0);
	voodoo3_write32(sc, VIDDESKSTRIDE, bytes_per_row);
	voodoo3_write32(sc, PLLCTRL0, vidpll);

	voodoo3_make_room(sc, 5);
	voodoo3_write32(sc, VIDSCREENSIZE, sc->sc_width |
	    (sc->sc_height << 12));
	voodoo3_write32(sc, VIDDESKSTART,  0);

	vidproc &= ~VIDCFG_HWCURSOR_ENABLE;
	voodoo3_write32(sc, VIDPROCCFG, vidproc);

	voodoo3_write32(sc, VGAINIT1, 0);
	voodoo3_write32(sc, MISCINIT0, miscinit0);
#ifdef VOODOOFB_DEBUG
	printf("vidproc: %08x\n", vidproc);
#endif
	voodoo3_make_room(sc, 8);
	voodoo3_write32(sc, SRCBASE, 0);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, COMMANDEXTRA_2D, 0);
  	voodoo3_write32(sc, CLIP0MIN,        0);
  	voodoo3_write32(sc, CLIP0MAX,        0x0fff0fff);
  	voodoo3_write32(sc, CLIP1MIN,        0);
  	voodoo3_write32(sc, CLIP1MAX,        0x0fff0fff);
	voodoo3_write32(sc, SRCXY, 0);
	voodoofb_wait_idle(sc);
	printf("%s: switched to %dx%d, %d bit\n", device_xname(sc->sc_dev),
	    sc->sc_width, sc->sc_height, sc->sc_bits_per_pixel);
	sc->sc_numglyphs = 0;	/* invalidate the glyph cache */
}

static void
voodoofb_init(struct voodoofb_softc *sc)
{
	/* XXX */
	uint32_t vgainit0 = 0;
	uint32_t vidcfg = 0;

#ifdef VOODOOFB_DEBUG
	printf("initializing engine...");
#endif
	vgainit0 = voodoo3_read32(sc, VGAINIT0);
#ifdef VOODOOFB_DEBUG
	printf("vga: %08x", vgainit0);
#endif
	vgainit0 |=
	    VGAINIT0_8BIT_DAC     |
	    VGAINIT0_EXT_ENABLE   |
	    VGAINIT0_WAKEUP_3C3   |
	    VGAINIT0_ALT_READBACK |
	    VGAINIT0_EXTSHIFTOUT;

	vidcfg = voodoo3_read32(sc, VIDPROCCFG);
#ifdef VOODOOFB_DEBUG
	printf(" vidcfg: %08x\n", vidcfg);
#endif
	vidcfg |=
	    VIDCFG_VIDPROC_ENABLE |
	    VIDCFG_DESK_ENABLE;
	vidcfg &= ~VIDCFG_HWCURSOR_ENABLE;

	voodoo3_make_room(sc, 2);

	voodoo3_write32(sc, VGAINIT0, vgainit0);
	voodoo3_write32(sc, VIDPROCCFG, vidcfg);

	voodoo3_make_room(sc, 8);
	voodoo3_write32(sc, SRCBASE, 0);
	voodoo3_write32(sc, DSTBASE, 0);
	voodoo3_write32(sc, COMMANDEXTRA_2D, 0);
  	voodoo3_write32(sc, CLIP0MIN,        0);
  	voodoo3_write32(sc, CLIP0MAX,        0x1fff1fff);
  	voodoo3_write32(sc, CLIP1MIN,        0);
  	voodoo3_write32(sc, CLIP1MAX,        0x1fff1fff);
	voodoo3_write32(sc, SRCXY, 0);

	voodoofb_wait_idle(sc);
}

#define MAX_CLOCK 250000	/* all Voodoo3 should support that */
#define MAX_HRES  1700		/*
				 * XXX in theory we can go higher but I
				 * couldn't get anything above 1680 x 1200
				 * to work, so until I find out why, it's
				 * disabled so people won't end up with a
				 * blank screen
				 */
#define MODE_IS_VALID(m) (((m)->dot_clock <= MAX_CLOCK) && \
					    ((m)->hdisplay < MAX_HRES))
static void
voodoofb_setup_i2c(struct voodoofb_softc *sc)
{
	int i;

	/* Fill in the i2c tag */
	sc->sc_i2c.ic_cookie = sc;
	sc->sc_i2c.ic_acquire_bus = voodoofb_i2c_acquire_bus;
	sc->sc_i2c.ic_release_bus = voodoofb_i2c_release_bus;
	sc->sc_i2c.ic_send_start = voodoofb_i2c_send_start;
	sc->sc_i2c.ic_send_stop = voodoofb_i2c_send_stop;
	sc->sc_i2c.ic_initiate_xfer = voodoofb_i2c_initiate_xfer;
	sc->sc_i2c.ic_read_byte = voodoofb_i2c_read_byte;
	sc->sc_i2c.ic_write_byte = voodoofb_i2c_write_byte;
	sc->sc_i2c.ic_exec = NULL;

	sc->sc_i2creg = voodoo3_read32(sc, VIDSERPARPORT);
#ifdef VOODOOFB_DEBUG
	printf("data: %08x\n", sc->sc_i2creg);
#endif
	sc->sc_i2creg |= VSP_ENABLE_IIC0;
	sc->sc_i2creg &= ~(VSP_SDA0_OUT | VSP_SCL0_OUT);
	voodoo3_write32(sc, VIDSERPARPORT, sc->sc_i2creg);

	/* zero out the EDID buffer */
	memset(sc->sc_edid_data, 0, 128);

	/* Some monitors don't respond first time */
	i = 0;
	while (sc->sc_edid_data[1] == 0 && i++ < 3)
		ddc_read_edid(&sc->sc_i2c, sc->sc_edid_data, 128);
	if (i < 3) {
		if (edid_parse(sc->sc_edid_data, &sc->sc_edid_info) != -1) {
#ifdef VOODOOFB_DEBUG
			edid_print(&sc->sc_edid_info);
#endif
			/*
			 * Now pick a mode.
			 * How do we know our max. pixel clock?
			 * All Voodoo3 should support at least 250MHz.
			 * All Voodoo3 I've seen so far have at least 8MB
			 * which we're not going to exhaust either in 8bit.
			 */
			if ((sc->sc_edid_info.edid_preferred_mode != NULL)) {
				struct videomode *m =
				    sc->sc_edid_info.edid_preferred_mode;
				if (MODE_IS_VALID(m)) {
					sc->sc_videomode = m;
				} else {
					aprint_error_dev(sc->sc_dev,
					    "unable to use preferred mode\n");
				}
			}
			/*
			 * if we can't use the preferred mode go look for the
			 * best one we can support
			 */
			if (sc->sc_videomode == NULL) {
				int n;
				struct videomode *m =
				     sc->sc_edid_info.edid_modes;

				sort_modes(sc->sc_edid_info.edid_modes,
			   	    &sc->sc_edid_info.edid_preferred_mode,
				    sc->sc_edid_info.edid_nmodes);
				while ((sc->sc_videomode == NULL) &&
				       (n < sc->sc_edid_info.edid_nmodes)) {
					if (MODE_IS_VALID(&m[n])) {
						sc->sc_videomode = &m[n];
					}
					n++;
				}
			}
		}
	}
}

/* I2C bitbanging */
static void voodoofb_i2cbb_set_bits(void *cookie, uint32_t bits)
{
	struct voodoofb_softc *sc = cookie;
	uint32_t out;

	out = bits >> 2;	/* bitmasks match the IN bits */

	voodoo3_write32(sc, VIDSERPARPORT, sc->sc_i2creg | out);
}

static void voodoofb_i2cbb_set_dir(void *cookie, uint32_t dir)
{
	/* Nothing to do */
}

static uint32_t voodoofb_i2cbb_read(void *cookie)
{
	struct voodoofb_softc *sc = cookie;
	uint32_t bits;

	bits = voodoo3_read32(sc, VIDSERPARPORT);

	return bits;
}

/* higher level I2C stuff */
static int
voodoofb_i2c_acquire_bus(void *cookie, int flags)
{
	/* private bus */
	return (0);
}

static void
voodoofb_i2c_release_bus(void *cookie, int flags)
{
	/* private bus */
}

static int
voodoofb_i2c_send_start(void *cookie, int flags)
{
	return (i2c_bitbang_send_start(cookie, flags, &voodoofb_i2cbb_ops));
}

static int
voodoofb_i2c_send_stop(void *cookie, int flags)
{

	return (i2c_bitbang_send_stop(cookie, flags, &voodoofb_i2cbb_ops));
}

static int
voodoofb_i2c_initiate_xfer(void *cookie, i2c_addr_t addr, int flags)
{

	return (i2c_bitbang_initiate_xfer(cookie, addr, flags,
	    &voodoofb_i2cbb_ops));
}

static int
voodoofb_i2c_read_byte(void *cookie, uint8_t *valp, int flags)
{
	return (i2c_bitbang_read_byte(cookie, valp, flags, &voodoofb_i2cbb_ops));
}

static int
voodoofb_i2c_write_byte(void *cookie, uint8_t val, int flags)
{
	return (i2c_bitbang_write_byte(cookie, val, flags, &voodoofb_i2cbb_ops));
}

/* glyph cache */
static void
voodoofb_init_glyphcache(struct voodoofb_softc *sc, struct rasops_info *ri)
{
	int bufsize, i;

	if (sc->sc_numglyphs != 0) {
		/* re-initialize */
		if (ri->ri_font == sc->sc_font) {
			/* nothing to do, keep using the same cache */
			return;
		}
	}
	sc->sc_cache = (ri->ri_width * ri->ri_stride + 3) & 0xfffffffc;
	bufsize = sc->sc_memsize - sc->sc_cache;
	sc->sc_numglyphs = bufsize / ri->ri_fontscale;
	sc->sc_usedglyphs = 0;
	for (i = 0; i < 256; i++) {
		sc->sc_glyphs_kernattr[i] = 0;
		sc->sc_glyphs_defattr[i] = 0;
	}
	sc->sc_fmt = ri->ri_font->fontwidth | FMT_8BIT;
}