drivers/gpu/drm/mgag200/mgag200_mode.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2010 Matt Turner.
 * Copyright 2012 Red Hat
 *
 * Authors: Matthew Garrett
 *	    Matt Turner
 *	    Dave Airlie
 */

#include <linux/delay.h>
#include <linux/pci.h>

#include <drm/drm_crtc_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>

#include "mgag200_drv.h"

#define MGAG200_LUT_SIZE 256

/*
 * This file contains setup code for the CRTC.
 */

static void mga_crtc_load_lut(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = to_mga_device(dev);
	struct drm_framebuffer *fb = crtc->primary->fb;
	u16 *r_ptr, *g_ptr, *b_ptr;
	int i;

	if (!crtc->enabled)
		return;

	r_ptr = crtc->gamma_store;
	g_ptr = r_ptr + crtc->gamma_size;
	b_ptr = g_ptr + crtc->gamma_size;

	WREG8(DAC_INDEX + MGA1064_INDEX, 0);

	if (fb && fb->format->cpp[0] * 8 == 16) {
		int inc = (fb->format->depth == 15) ? 8 : 4;
		u8 r, b;
		for (i = 0; i < MGAG200_LUT_SIZE; i += inc) {
			if (fb->format->depth == 16) {
				if (i > (MGAG200_LUT_SIZE >> 1)) {
					r = b = 0;
				} else {
					r = *r_ptr++ >> 8;
					b = *b_ptr++ >> 8;
					r_ptr++;
					b_ptr++;
				}
			} else {
				r = *r_ptr++ >> 8;
				b = *b_ptr++ >> 8;
			}
			/* VGA registers */
			WREG8(DAC_INDEX + MGA1064_COL_PAL, r);
			WREG8(DAC_INDEX + MGA1064_COL_PAL, *g_ptr++ >> 8);
			WREG8(DAC_INDEX + MGA1064_COL_PAL, b);
		}
		return;
	}
	for (i = 0; i < MGAG200_LUT_SIZE; i++) {
		/* VGA registers */
		WREG8(DAC_INDEX + MGA1064_COL_PAL, *r_ptr++ >> 8);
		WREG8(DAC_INDEX + MGA1064_COL_PAL, *g_ptr++ >> 8);
		WREG8(DAC_INDEX + MGA1064_COL_PAL, *b_ptr++ >> 8);
	}
}

static inline void mga_wait_vsync(struct mga_device *mdev)
{
	unsigned long timeout = jiffies + HZ/10;
	unsigned int status = 0;

	do {
		status = RREG32(MGAREG_Status);
	} while ((status & 0x08) && time_before(jiffies, timeout));
	timeout = jiffies + HZ/10;
	status = 0;
	do {
		status = RREG32(MGAREG_Status);
	} while (!(status & 0x08) && time_before(jiffies, timeout));
}

static inline void mga_wait_busy(struct mga_device *mdev)
{
	unsigned long timeout = jiffies + HZ;
	unsigned int status = 0;
	do {
		status = RREG8(MGAREG_Status + 2);
	} while ((status & 0x01) && time_before(jiffies, timeout));
}

#define P_ARRAY_SIZE 9

static int mga_g200se_set_plls(struct mga_device *mdev, long clock)
{
	unsigned int vcomax, vcomin, pllreffreq;
	unsigned int delta, tmpdelta, permitteddelta;
	unsigned int testp, testm, testn;
	unsigned int p, m, n;
	unsigned int computed;
	unsigned int pvalues_e4[P_ARRAY_SIZE] = {16, 14, 12, 10, 8, 6, 4, 2, 1};
	unsigned int fvv;
	unsigned int i;

	if (mdev->unique_rev_id <= 0x03) {

		m = n = p = 0;
		vcomax = 320000;
		vcomin = 160000;
		pllreffreq = 25000;

		delta = 0xffffffff;
		permitteddelta = clock * 5 / 1000;

		for (testp = 8; testp > 0; testp /= 2) {
			if (clock * testp > vcomax)
				continue;
			if (clock * testp < vcomin)
				continue;

			for (testn = 17; testn < 256; testn++) {
				for (testm = 1; testm < 32; testm++) {
					computed = (pllreffreq * testn) /
						(testm * testp);
					if (computed > clock)
						tmpdelta = computed - clock;
					else
						tmpdelta = clock - computed;
					if (tmpdelta < delta) {
						delta = tmpdelta;
						m = testm - 1;
						n = testn - 1;
						p = testp - 1;
					}
				}
			}
		}
	} else {


		m = n = p = 0;
		vcomax        = 1600000;
		vcomin        = 800000;
		pllreffreq    = 25000;

		if (clock < 25000)
			clock = 25000;

		clock = clock * 2;

		delta = 0xFFFFFFFF;
		/* Permited delta is 0.5% as VESA Specification */
		permitteddelta = clock * 5 / 1000;

		for (i = 0 ; i < P_ARRAY_SIZE ; i++) {
			testp = pvalues_e4[i];

			if ((clock * testp) > vcomax)
				continue;
			if ((clock * testp) < vcomin)
				continue;

			for (testn = 50; testn <= 256; testn++) {
				for (testm = 1; testm <= 32; testm++) {
					computed = (pllreffreq * testn) /
						(testm * testp);
					if (computed > clock)
						tmpdelta = computed - clock;
					else
						tmpdelta = clock - computed;

					if (tmpdelta < delta) {
						delta = tmpdelta;
						m = testm - 1;
						n = testn - 1;
						p = testp - 1;
					}
				}
			}
		}

		fvv = pllreffreq * (n + 1) / (m + 1);
		fvv = (fvv - 800000) / 50000;

		if (fvv > 15)
			fvv = 15;

		p |= (fvv << 4);
		m |= 0x80;

		clock = clock / 2;
	}

	if (delta > permitteddelta) {
		pr_warn("PLL delta too large\n");
		return 1;
	}

	WREG_DAC(MGA1064_PIX_PLLC_M, m);
	WREG_DAC(MGA1064_PIX_PLLC_N, n);
	WREG_DAC(MGA1064_PIX_PLLC_P, p);

	if (mdev->unique_rev_id >= 0x04) {
		WREG_DAC(0x1a, 0x09);
		msleep(20);
		WREG_DAC(0x1a, 0x01);

	}

	return 0;
}

static int mga_g200wb_set_plls(struct mga_device *mdev, long clock)
{
	unsigned int vcomax, vcomin, pllreffreq;
	unsigned int delta, tmpdelta;
	unsigned int testp, testm, testn, testp2;
	unsigned int p, m, n;
	unsigned int computed;
	int i, j, tmpcount, vcount;
	bool pll_locked = false;
	u8 tmp;

	m = n = p = 0;

	delta = 0xffffffff;

	if (mdev->type == G200_EW3) {

		vcomax = 800000;
		vcomin = 400000;
		pllreffreq = 25000;

		for (testp = 1; testp < 8; testp++) {
			for (testp2 = 1; testp2 < 8; testp2++) {
				if (testp < testp2)
					continue;
				if ((clock * testp * testp2) > vcomax)
					continue;
				if ((clock * testp * testp2) < vcomin)
					continue;
				for (testm = 1; testm < 26; testm++) {
					for (testn = 32; testn < 2048 ; testn++) {
						computed = (pllreffreq * testn) /
							(testm * testp * testp2);
						if (computed > clock)
							tmpdelta = computed - clock;
						else
							tmpdelta = clock - computed;
						if (tmpdelta < delta) {
							delta = tmpdelta;
							m = ((testn & 0x100) >> 1) |
								(testm);
							n = (testn & 0xFF);
							p = ((testn & 0x600) >> 3) |
								(testp2 << 3) |
								(testp);
						}
					}
				}
			}
		}
	} else {

		vcomax = 550000;
		vcomin = 150000;
		pllreffreq = 48000;

		for (testp = 1; testp < 9; testp++) {
			if (clock * testp > vcomax)
				continue;
			if (clock * testp < vcomin)
				continue;

			for (testm = 1; testm < 17; testm++) {
				for (testn = 1; testn < 151; testn++) {
					computed = (pllreffreq * testn) /
						(testm * testp);
					if (computed > clock)
						tmpdelta = computed - clock;
					else
						tmpdelta = clock - computed;
					if (tmpdelta < delta) {
						delta = tmpdelta;
						n = testn - 1;
						m = (testm - 1) |
							((n >> 1) & 0x80);
						p = testp - 1;
					}
				}
			}
		}
	}

	for (i = 0; i <= 32 && pll_locked == false; i++) {
		if (i > 0) {
			WREG8(MGAREG_CRTC_INDEX, 0x1e);
			tmp = RREG8(MGAREG_CRTC_DATA);
			if (tmp < 0xff)
				WREG8(MGAREG_CRTC_DATA, tmp+1);
		}

		/* set pixclkdis to 1 */
		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp |= MGA1064_PIX_CLK_CTL_CLK_DIS;
		WREG8(DAC_DATA, tmp);

		WREG8(DAC_INDEX, MGA1064_REMHEADCTL);
		tmp = RREG8(DAC_DATA);
		tmp |= MGA1064_REMHEADCTL_CLKDIS;
		WREG8(DAC_DATA, tmp);

		/* select PLL Set C */
		tmp = RREG8(MGAREG_MEM_MISC_READ);
		tmp |= 0x3 << 2;
		WREG8(MGAREG_MEM_MISC_WRITE, tmp);

		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp |= MGA1064_PIX_CLK_CTL_CLK_POW_DOWN | 0x80;
		WREG8(DAC_DATA, tmp);

		udelay(500);

		/* reset the PLL */
		WREG8(DAC_INDEX, MGA1064_VREF_CTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~0x04;
		WREG8(DAC_DATA, tmp);

		udelay(50);

		/* program pixel pll register */
		WREG_DAC(MGA1064_WB_PIX_PLLC_N, n);
		WREG_DAC(MGA1064_WB_PIX_PLLC_M, m);
		WREG_DAC(MGA1064_WB_PIX_PLLC_P, p);

		udelay(50);

		/* turn pll on */
		WREG8(DAC_INDEX, MGA1064_VREF_CTL);
		tmp = RREG8(DAC_DATA);
		tmp |= 0x04;
		WREG_DAC(MGA1064_VREF_CTL, tmp);

		udelay(500);

		/* select the pixel pll */
		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~MGA1064_PIX_CLK_CTL_SEL_MSK;
		tmp |= MGA1064_PIX_CLK_CTL_SEL_PLL;
		WREG8(DAC_DATA, tmp);

		WREG8(DAC_INDEX, MGA1064_REMHEADCTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~MGA1064_REMHEADCTL_CLKSL_MSK;
		tmp |= MGA1064_REMHEADCTL_CLKSL_PLL;
		WREG8(DAC_DATA, tmp);

		/* reset dotclock rate bit */
		WREG8(MGAREG_SEQ_INDEX, 1);
		tmp = RREG8(MGAREG_SEQ_DATA);
		tmp &= ~0x8;
		WREG8(MGAREG_SEQ_DATA, tmp);

		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~MGA1064_PIX_CLK_CTL_CLK_DIS;
		WREG8(DAC_DATA, tmp);

		vcount = RREG8(MGAREG_VCOUNT);

		for (j = 0; j < 30 && pll_locked == false; j++) {
			tmpcount = RREG8(MGAREG_VCOUNT);
			if (tmpcount < vcount)
				vcount = 0;
			if ((tmpcount - vcount) > 2)
				pll_locked = true;
			else
				udelay(5);
		}
	}
	WREG8(DAC_INDEX, MGA1064_REMHEADCTL);
	tmp = RREG8(DAC_DATA);
	tmp &= ~MGA1064_REMHEADCTL_CLKDIS;
	WREG_DAC(MGA1064_REMHEADCTL, tmp);
	return 0;
}

static int mga_g200ev_set_plls(struct mga_device *mdev, long clock)
{
	unsigned int vcomax, vcomin, pllreffreq;
	unsigned int delta, tmpdelta;
	unsigned int testp, testm, testn;
	unsigned int p, m, n;
	unsigned int computed;
	u8 tmp;

	m = n = p = 0;
	vcomax = 550000;
	vcomin = 150000;
	pllreffreq = 50000;

	delta = 0xffffffff;

	for (testp = 16; testp > 0; testp--) {
		if (clock * testp > vcomax)
			continue;
		if (clock * testp < vcomin)
			continue;

		for (testn = 1; testn < 257; testn++) {
			for (testm = 1; testm < 17; testm++) {
				computed = (pllreffreq * testn) /
					(testm * testp);
				if (computed > clock)
					tmpdelta = computed - clock;
				else
					tmpdelta = clock - computed;
				if (tmpdelta < delta) {
					delta = tmpdelta;
					n = testn - 1;
					m = testm - 1;
					p = testp - 1;
				}
			}
		}
	}

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp |= MGA1064_PIX_CLK_CTL_CLK_DIS;
	WREG8(DAC_DATA, tmp);

	tmp = RREG8(MGAREG_MEM_MISC_READ);
	tmp |= 0x3 << 2;
	WREG8(MGAREG_MEM_MISC_WRITE, tmp);

	WREG8(DAC_INDEX, MGA1064_PIX_PLL_STAT);
	tmp = RREG8(DAC_DATA);
	WREG8(DAC_DATA, tmp & ~0x40);

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp |= MGA1064_PIX_CLK_CTL_CLK_POW_DOWN;
	WREG8(DAC_DATA, tmp);

	WREG_DAC(MGA1064_EV_PIX_PLLC_M, m);
	WREG_DAC(MGA1064_EV_PIX_PLLC_N, n);
	WREG_DAC(MGA1064_EV_PIX_PLLC_P, p);

	udelay(50);

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp &= ~MGA1064_PIX_CLK_CTL_CLK_POW_DOWN;
	WREG8(DAC_DATA, tmp);

	udelay(500);

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp &= ~MGA1064_PIX_CLK_CTL_SEL_MSK;
	tmp |= MGA1064_PIX_CLK_CTL_SEL_PLL;
	WREG8(DAC_DATA, tmp);

	WREG8(DAC_INDEX, MGA1064_PIX_PLL_STAT);
	tmp = RREG8(DAC_DATA);
	WREG8(DAC_DATA, tmp | 0x40);

	tmp = RREG8(MGAREG_MEM_MISC_READ);
	tmp |= (0x3 << 2);
	WREG8(MGAREG_MEM_MISC_WRITE, tmp);

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp &= ~MGA1064_PIX_CLK_CTL_CLK_DIS;
	WREG8(DAC_DATA, tmp);

	return 0;
}

static int mga_g200eh_set_plls(struct mga_device *mdev, long clock)
{
	unsigned int vcomax, vcomin, pllreffreq;
	unsigned int delta, tmpdelta;
	unsigned int testp, testm, testn;
	unsigned int p, m, n;
	unsigned int computed;
	int i, j, tmpcount, vcount;
	u8 tmp;
	bool pll_locked = false;

	m = n = p = 0;

	if (mdev->type == G200_EH3) {
		vcomax = 3000000;
		vcomin = 1500000;
		pllreffreq = 25000;

		delta = 0xffffffff;

		testp = 0;

		for (testm = 150; testm >= 6; testm--) {
			if (clock * testm > vcomax)
				continue;
			if (clock * testm < vcomin)
				continue;
			for (testn = 120; testn >= 60; testn--) {
				computed = (pllreffreq * testn) / testm;
				if (computed > clock)
					tmpdelta = computed - clock;
				else
					tmpdelta = clock - computed;
				if (tmpdelta < delta) {
					delta = tmpdelta;
					n = testn;
					m = testm;
					p = testp;
				}
				if (delta == 0)
					break;
			}
			if (delta == 0)
				break;
		}
	} else {

		vcomax = 800000;
		vcomin = 400000;
		pllreffreq = 33333;

		delta = 0xffffffff;

		for (testp = 16; testp > 0; testp >>= 1) {
			if (clock * testp > vcomax)
				continue;
			if (clock * testp < vcomin)
				continue;

			for (testm = 1; testm < 33; testm++) {
				for (testn = 17; testn < 257; testn++) {
					computed = (pllreffreq * testn) /
						(testm * testp);
					if (computed > clock)
						tmpdelta = computed - clock;
					else
						tmpdelta = clock - computed;
					if (tmpdelta < delta) {
						delta = tmpdelta;
						n = testn - 1;
						m = (testm - 1);
						p = testp - 1;
					}
					if ((clock * testp) >= 600000)
						p |= 0x80;
				}
			}
		}
	}
	for (i = 0; i <= 32 && pll_locked == false; i++) {
		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp |= MGA1064_PIX_CLK_CTL_CLK_DIS;
		WREG8(DAC_DATA, tmp);

		tmp = RREG8(MGAREG_MEM_MISC_READ);
		tmp |= 0x3 << 2;
		WREG8(MGAREG_MEM_MISC_WRITE, tmp);

		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp |= MGA1064_PIX_CLK_CTL_CLK_POW_DOWN;
		WREG8(DAC_DATA, tmp);

		udelay(500);

		WREG_DAC(MGA1064_EH_PIX_PLLC_M, m);
		WREG_DAC(MGA1064_EH_PIX_PLLC_N, n);
		WREG_DAC(MGA1064_EH_PIX_PLLC_P, p);

		udelay(500);

		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~MGA1064_PIX_CLK_CTL_SEL_MSK;
		tmp |= MGA1064_PIX_CLK_CTL_SEL_PLL;
		WREG8(DAC_DATA, tmp);

		WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
		tmp = RREG8(DAC_DATA);
		tmp &= ~MGA1064_PIX_CLK_CTL_CLK_DIS;
		tmp &= ~MGA1064_PIX_CLK_CTL_CLK_POW_DOWN;
		WREG8(DAC_DATA, tmp);

		vcount = RREG8(MGAREG_VCOUNT);

		for (j = 0; j < 30 && pll_locked == false; j++) {
			tmpcount = RREG8(MGAREG_VCOUNT);
			if (tmpcount < vcount)
				vcount = 0;
			if ((tmpcount - vcount) > 2)
				pll_locked = true;
			else
				udelay(5);
		}
	}

	return 0;
}

static int mga_g200er_set_plls(struct mga_device *mdev, long clock)
{
	unsigned int vcomax, vcomin, pllreffreq;
	unsigned int delta, tmpdelta;
	int testr, testn, testm, testo;
	unsigned int p, m, n;
	unsigned int computed, vco;
	int tmp;
	const unsigned int m_div_val[] = { 1, 2, 4, 8 };

	m = n = p = 0;
	vcomax = 1488000;
	vcomin = 1056000;
	pllreffreq = 48000;

	delta = 0xffffffff;

	for (testr = 0; testr < 4; testr++) {
		if (delta == 0)
			break;
		for (testn = 5; testn < 129; testn++) {
			if (delta == 0)
				break;
			for (testm = 3; testm >= 0; testm--) {
				if (delta == 0)
					break;
				for (testo = 5; testo < 33; testo++) {
					vco = pllreffreq * (testn + 1) /
						(testr + 1);
					if (vco < vcomin)
						continue;
					if (vco > vcomax)
						continue;
					computed = vco / (m_div_val[testm] * (testo + 1));
					if (computed > clock)
						tmpdelta = computed - clock;
					else
						tmpdelta = clock - computed;
					if (tmpdelta < delta) {
						delta = tmpdelta;
						m = testm | (testo << 3);
						n = testn;
						p = testr | (testr << 3);
					}
				}
			}
		}
	}

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp |= MGA1064_PIX_CLK_CTL_CLK_DIS;
	WREG8(DAC_DATA, tmp);

	WREG8(DAC_INDEX, MGA1064_REMHEADCTL);
	tmp = RREG8(DAC_DATA);
	tmp |= MGA1064_REMHEADCTL_CLKDIS;
	WREG8(DAC_DATA, tmp);

	tmp = RREG8(MGAREG_MEM_MISC_READ);
	tmp |= (0x3<<2) | 0xc0;
	WREG8(MGAREG_MEM_MISC_WRITE, tmp);

	WREG8(DAC_INDEX, MGA1064_PIX_CLK_CTL);
	tmp = RREG8(DAC_DATA);
	tmp &= ~MGA1064_PIX_CLK_CTL_CLK_DIS;
	tmp |= MGA1064_PIX_CLK_CTL_CLK_POW_DOWN;
	WREG8(DAC_DATA, tmp);

	udelay(500);

	WREG_DAC(MGA1064_ER_PIX_PLLC_N, n);
	WREG_DAC(MGA1064_ER_PIX_PLLC_M, m);
	WREG_DAC(MGA1064_ER_PIX_PLLC_P, p);

	udelay(50);

	return 0;
}

static int mga_crtc_set_plls(struct mga_device *mdev, long clock)
{
	u8 misc;

	switch(mdev->type) {
	case G200_SE_A:
	case G200_SE_B:
		return mga_g200se_set_plls(mdev, clock);
		break;
	case G200_WB:
	case G200_EW3:
		return mga_g200wb_set_plls(mdev, clock);
		break;
	case G200_EV:
		return mga_g200ev_set_plls(mdev, clock);
		break;
	case G200_EH:
	case G200_EH3:
		return mga_g200eh_set_plls(mdev, clock);
		break;
	case G200_ER:
		return mga_g200er_set_plls(mdev, clock);
		break;
	}

	misc = RREG8(MGA_MISC_IN);
	misc &= ~MGAREG_MISC_CLK_SEL_MASK;
	misc |= MGAREG_MISC_CLK_SEL_MGA_MSK;
	WREG8(MGA_MISC_OUT, misc);

	return 0;
}

static void mga_g200wb_prepare(struct drm_crtc *crtc)
{
	struct mga_device *mdev = to_mga_device(crtc->dev);
	u8 tmp;
	int iter_max;

	/* 1- The first step is to warn the BMC of an upcoming mode change.
	 * We are putting the misc<0> to output.*/

	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
	tmp = RREG8(DAC_DATA);
	tmp |= 0x10;
	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);

	/* we are putting a 1 on the misc<0> line */
	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
	tmp = RREG8(DAC_DATA);
	tmp |= 0x10;
	WREG_DAC(MGA1064_GEN_IO_DATA, tmp);

	/* 2- Second step to mask and further scan request
	 * This will be done by asserting the remfreqmsk bit (XSPAREREG<7>)
	 */
	WREG8(DAC_INDEX, MGA1064_SPAREREG);
	tmp = RREG8(DAC_DATA);
	tmp |= 0x80;
	WREG_DAC(MGA1064_SPAREREG, tmp);

	/* 3a- the third step is to verifu if there is an active scan
	 * We are searching for a 0 on remhsyncsts <XSPAREREG<0>)
	 */
	iter_max = 300;
	while (!(tmp & 0x1) && iter_max) {
		WREG8(DAC_INDEX, MGA1064_SPAREREG);
		tmp = RREG8(DAC_DATA);
		udelay(1000);
		iter_max--;
	}

	/* 3b- this step occurs only if the remove is actually scanning
	 * we are waiting for the end of the frame which is a 1 on
	 * remvsyncsts (XSPAREREG<1>)
	 */
	if (iter_max) {
		iter_max = 300;
		while ((tmp & 0x2) && iter_max) {
			WREG8(DAC_INDEX, MGA1064_SPAREREG);
			tmp = RREG8(DAC_DATA);
			udelay(1000);
			iter_max--;
		}
	}
}

static void mga_g200wb_commit(struct drm_crtc *crtc)
{
	u8 tmp;
	struct mga_device *mdev = to_mga_device(crtc->dev);

	/* 1- The first step is to ensure that the vrsten and hrsten are set */
	WREG8(MGAREG_CRTCEXT_INDEX, 1);
	tmp = RREG8(MGAREG_CRTCEXT_DATA);
	WREG8(MGAREG_CRTCEXT_DATA, tmp | 0x88);

	/* 2- second step is to assert the rstlvl2 */
	WREG8(DAC_INDEX, MGA1064_REMHEADCTL2);
	tmp = RREG8(DAC_DATA);
	tmp |= 0x8;
	WREG8(DAC_DATA, tmp);

	/* wait 10 us */
	udelay(10);

	/* 3- deassert rstlvl2 */
	tmp &= ~0x08;
	WREG8(DAC_INDEX, MGA1064_REMHEADCTL2);
	WREG8(DAC_DATA, tmp);

	/* 4- remove mask of scan request */
	WREG8(DAC_INDEX, MGA1064_SPAREREG);
	tmp = RREG8(DAC_DATA);
	tmp &= ~0x80;
	WREG8(DAC_DATA, tmp);

	/* 5- put back a 0 on the misc<0> line */
	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
	tmp = RREG8(DAC_DATA);
	tmp &= ~0x10;
	WREG_DAC(MGA1064_GEN_IO_DATA, tmp);
}

/*
 * This is how the framebuffer base address is stored in g200 cards:
 *   * Assume @offset is the gpu_addr variable of the framebuffer object
 *   * Then addr is the number of _pixels_ (not bytes) from the start of
 *     VRAM to the first pixel we want to display. (divided by 2 for 32bit
 *     framebuffers)
 *   * addr is stored in the CRTCEXT0, CRTCC and CRTCD registers
 *      addr<20> -> CRTCEXT0<6>
 *      addr<19-16> -> CRTCEXT0<3-0>
 *      addr<15-8> -> CRTCC<7-0>
 *      addr<7-0> -> CRTCD<7-0>
 *
 *  CRTCEXT0 has to be programmed last to trigger an update and make the
 *  new addr variable take effect.
 */
static void mgag200_set_startadd(struct mga_device *mdev,
				 unsigned long offset)
{
	struct drm_device *dev = mdev->dev;
	u32 startadd;
	u8 crtcc, crtcd, crtcext0;

	startadd = offset / 8;

	/*
	 * Can't store addresses any higher than that, but we also
	 * don't have more than 16 MiB of memory, so it should be fine.
	 */
	drm_WARN_ON(dev, startadd > 0x1fffff);

	RREG_ECRT(0x00, crtcext0);

	crtcc = (startadd >> 8) & 0xff;
	crtcd = startadd & 0xff;
	crtcext0 &= 0xb0;
	crtcext0 |= ((startadd >> 14) & BIT(6)) |
		    ((startadd >> 16) & 0x0f);

	WREG_CRT(0x0c, crtcc);
	WREG_CRT(0x0d, crtcd);
	WREG_ECRT(0x00, crtcext0);
}

static int mga_crtc_do_set_base(struct mga_device *mdev,
				const struct drm_framebuffer *fb,
				const struct drm_framebuffer *old_fb)
{
	struct drm_gem_vram_object *gbo;
	int ret;
	s64 gpu_addr;

	if (old_fb) {
		gbo = drm_gem_vram_of_gem(old_fb->obj[0]);
		drm_gem_vram_unpin(gbo);
	}

	gbo = drm_gem_vram_of_gem(fb->obj[0]);

	ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);
	if (ret)
		return ret;
	gpu_addr = drm_gem_vram_offset(gbo);
	if (gpu_addr < 0) {
		ret = (int)gpu_addr;
		goto err_drm_gem_vram_unpin;
	}

	mgag200_set_startadd(mdev, (unsigned long)gpu_addr);

	return 0;

err_drm_gem_vram_unpin:
	drm_gem_vram_unpin(gbo);
	return ret;
}

static int mga_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
				  struct drm_framebuffer *old_fb)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = dev->dev_private;
	struct drm_framebuffer *fb = crtc->primary->fb;
	unsigned int count;

	do { } while (RREG8(0x1fda) & 0x08);
	do { } while (!(RREG8(0x1fda) & 0x08));

	count = RREG8(MGAREG_VCOUNT) + 2;
	do { } while (RREG8(MGAREG_VCOUNT) < count);

	return mga_crtc_do_set_base(mdev, fb, old_fb);
}

static void mgag200_set_mode_regs(struct mga_device *mdev,
				  const struct drm_display_mode *mode)
{
	unsigned int hdisplay, hsyncstart, hsyncend, htotal;
	unsigned int vdisplay, vsyncstart, vsyncend, vtotal;
	u8 misc, crtcext1, crtcext2, crtcext5;

	hdisplay = mode->hdisplay / 8 - 1;
	hsyncstart = mode->hsync_start / 8 - 1;
	hsyncend = mode->hsync_end / 8 - 1;
	htotal = mode->htotal / 8 - 1;

	/* Work around hardware quirk */
	if ((htotal & 0x07) == 0x06 || (htotal & 0x07) == 0x04)
		htotal++;

	vdisplay = mode->vdisplay - 1;
	vsyncstart = mode->vsync_start - 1;
	vsyncend = mode->vsync_end - 1;
	vtotal = mode->vtotal - 2;

	misc = RREG8(MGA_MISC_IN);

	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
		misc |= MGAREG_MISC_HSYNCPOL;
	else
		misc &= ~MGAREG_MISC_HSYNCPOL;

	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
		misc |= MGAREG_MISC_VSYNCPOL;
	else
		misc &= ~MGAREG_MISC_VSYNCPOL;

	crtcext1 = (((htotal - 4) & 0x100) >> 8) |
		   ((hdisplay & 0x100) >> 7) |
		   ((hsyncstart & 0x100) >> 6) |
		    (htotal & 0x40);
	if (mdev->type == G200_WB || mdev->type == G200_EW3)
		crtcext1 |= BIT(7) | /* vrsten */
			    BIT(3); /* hrsten */

	crtcext2 = ((vtotal & 0xc00) >> 10) |
		   ((vdisplay & 0x400) >> 8) |
		   ((vdisplay & 0xc00) >> 7) |
		   ((vsyncstart & 0xc00) >> 5) |
		   ((vdisplay & 0x400) >> 3);
	crtcext5 = 0x00;

	WREG_CRT(0, htotal - 4);
	WREG_CRT(1, hdisplay);
	WREG_CRT(2, hdisplay);
	WREG_CRT(3, (htotal & 0x1F) | 0x80);
	WREG_CRT(4, hsyncstart);
	WREG_CRT(5, ((htotal & 0x20) << 2) | (hsyncend & 0x1F));
	WREG_CRT(6, vtotal & 0xFF);
	WREG_CRT(7, ((vtotal & 0x100) >> 8) |
		 ((vdisplay & 0x100) >> 7) |
		 ((vsyncstart & 0x100) >> 6) |
		 ((vdisplay & 0x100) >> 5) |
		 ((vdisplay & 0x100) >> 4) | /* linecomp */
		 ((vtotal & 0x200) >> 4) |
		 ((vdisplay & 0x200) >> 3) |
		 ((vsyncstart & 0x200) >> 2));
	WREG_CRT(9, ((vdisplay & 0x200) >> 4) |
		 ((vdisplay & 0x200) >> 3));
	WREG_CRT(16, vsyncstart & 0xFF);
	WREG_CRT(17, (vsyncend & 0x0F) | 0x20);
	WREG_CRT(18, vdisplay & 0xFF);
	WREG_CRT(20, 0);
	WREG_CRT(21, vdisplay & 0xFF);
	WREG_CRT(22, (vtotal + 1) & 0xFF);
	WREG_CRT(23, 0xc3);
	WREG_CRT(24, vdisplay & 0xFF);

	WREG_ECRT(0x01, crtcext1);
	WREG_ECRT(0x02, crtcext2);
	WREG_ECRT(0x05, crtcext5);

	WREG8(MGA_MISC_OUT, misc);

	mga_crtc_set_plls(mdev, mode->clock);
}

static u8 mgag200_get_bpp_shift(struct mga_device *mdev,
				const struct drm_format_info *format)
{
	return mdev->bpp_shifts[format->cpp[0] - 1];
}

/*
 * Calculates the HW offset value from the framebuffer's pitch. The
 * offset is a multiple of the pixel size and depends on the display
 * format.
 */
static u32 mgag200_calculate_offset(struct mga_device *mdev,
				    const struct drm_framebuffer *fb)
{
	u32 offset = fb->pitches[0] / fb->format->cpp[0];
	u8 bppshift = mgag200_get_bpp_shift(mdev, fb->format);

	if (fb->format->cpp[0] * 8 == 24)
		offset = (offset * 3) >> (4 - bppshift);
	else
		offset = offset >> (4 - bppshift);

	return offset;
}

static void mgag200_set_offset(struct mga_device *mdev,
			       const struct drm_framebuffer *fb)
{
	u8 crtc13, crtcext0;
	u32 offset = mgag200_calculate_offset(mdev, fb);

	RREG_ECRT(0, crtcext0);

	crtc13 = offset & 0xff;

	crtcext0 &= ~MGAREG_CRTCEXT0_OFFSET_MASK;
	crtcext0 |= (offset >> 4) & MGAREG_CRTCEXT0_OFFSET_MASK;

	WREG_CRT(0x13, crtc13);
	WREG_ECRT(0x00, crtcext0);
}

static void mgag200_set_format_regs(struct mga_device *mdev,
				    const struct drm_framebuffer *fb)
{
	struct drm_device *dev = mdev->dev;
	const struct drm_format_info *format = fb->format;
	unsigned int bpp, bppshift, scale;
	u8 crtcext3, xmulctrl;

	bpp = format->cpp[0] * 8;

	bppshift = mgag200_get_bpp_shift(mdev, format);
	switch (bpp) {
	case 24:
		scale = ((1 << bppshift) * 3) - 1;
		break;
	default:
		scale = (1 << bppshift) - 1;
		break;
	}

	RREG_ECRT(3, crtcext3);

	switch (bpp) {
	case 8:
		xmulctrl = MGA1064_MUL_CTL_8bits;
		break;
	case 16:
		if (format->depth == 15)
			xmulctrl = MGA1064_MUL_CTL_15bits;
		else
			xmulctrl = MGA1064_MUL_CTL_16bits;
		break;
	case 24:
		xmulctrl = MGA1064_MUL_CTL_24bits;
		break;
	case 32:
		xmulctrl = MGA1064_MUL_CTL_32_24bits;
		break;
	default:
		/* BUG: We should have caught this problem already. */
		drm_WARN_ON(dev, "invalid format depth\n");
		return;
	}

	crtcext3 &= ~GENMASK(2, 0);
	crtcext3 |= scale;

	WREG_DAC(MGA1064_MUL_CTL, xmulctrl);

	WREG_GFX(0, 0x00);
	WREG_GFX(1, 0x00);
	WREG_GFX(2, 0x00);
	WREG_GFX(3, 0x00);
	WREG_GFX(4, 0x00);
	WREG_GFX(5, 0x40);
	WREG_GFX(6, 0x05);
	WREG_GFX(7, 0x0f);
	WREG_GFX(8, 0x0f);

	WREG_ECRT(3, crtcext3);
}

static void mgag200_g200er_reset_tagfifo(struct mga_device *mdev)
{
	static uint32_t RESET_FLAG = 0x00200000; /* undocumented magic value */
	u8 seq1;
	u32 memctl;

	/* screen off */
	RREG_SEQ(0x01, seq1);
	seq1 |= MGAREG_SEQ1_SCROFF;
	WREG_SEQ(0x01, seq1);

	memctl = RREG32(MGAREG_MEMCTL);

	memctl |= RESET_FLAG;
	WREG32(MGAREG_MEMCTL, memctl);

	udelay(1000);

	memctl &= ~RESET_FLAG;
	WREG32(MGAREG_MEMCTL, memctl);

	/* screen on */
	RREG_SEQ(0x01, seq1);
	seq1 &= ~MGAREG_SEQ1_SCROFF;
	WREG_SEQ(0x01, seq1);
}

static void mgag200_g200se_set_hiprilvl(struct mga_device *mdev,
					const struct drm_display_mode *mode,
					const struct drm_framebuffer *fb)
{
	unsigned int hiprilvl;
	u8 crtcext6;

	if  (mdev->unique_rev_id >= 0x04) {
		hiprilvl = 0;
	} else if (mdev->unique_rev_id >= 0x02) {
		unsigned int bpp;
		unsigned long mb;

		if (fb->format->cpp[0] * 8 > 16)
			bpp = 32;
		else if (fb->format->cpp[0] * 8 > 8)
			bpp = 16;
		else
			bpp = 8;

		mb = (mode->clock * bpp) / 1000;
		if (mb > 3100)
			hiprilvl = 0;
		else if (mb > 2600)
			hiprilvl = 1;
		else if (mb > 1900)
			hiprilvl = 2;
		else if (mb > 1160)
			hiprilvl = 3;
		else if (mb > 440)
			hiprilvl = 4;
		else
			hiprilvl = 5;

	} else if (mdev->unique_rev_id >= 0x01) {
		hiprilvl = 3;
	} else {
		hiprilvl = 4;
	}

	crtcext6 = hiprilvl; /* implicitly sets maxhipri to 0 */

	WREG_ECRT(0x06, crtcext6);
}

static void mgag200_g200ev_set_hiprilvl(struct mga_device *mdev)
{
	WREG_ECRT(0x06, 0x00);
}

static int mga_crtc_mode_set(struct drm_crtc *crtc,
				struct drm_display_mode *mode,
				struct drm_display_mode *adjusted_mode,
				int x, int y, struct drm_framebuffer *old_fb)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = to_mga_device(dev);
	const struct drm_framebuffer *fb = crtc->primary->fb;
	int option = 0, option2 = 0;
	int i;
	unsigned char misc = 0;
	u8 crtcext3, crtcext4;

	static unsigned char dacvalue[] = {
		/* 0x00: */        0,    0,    0,    0,    0,    0, 0x00,    0,
		/* 0x08: */        0,    0,    0,    0,    0,    0,    0,    0,
		/* 0x10: */        0,    0,    0,    0,    0,    0,    0,    0,
		/* 0x18: */     0x00,    0, 0xC9, 0xFF, 0xBF, 0x20, 0x1F, 0x20,
		/* 0x20: */     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		/* 0x28: */     0x00, 0x00, 0x00, 0x00,    0,    0,    0, 0x40,
		/* 0x30: */     0x00, 0xB0, 0x00, 0xC2, 0x34, 0x14, 0x02, 0x83,
		/* 0x38: */     0x00, 0x93, 0x00, 0x77, 0x00, 0x00, 0x00, 0x3A,
		/* 0x40: */        0,    0,    0,    0,    0,    0,    0,    0,
		/* 0x48: */        0,    0,    0,    0,    0,    0,    0,    0
	};

	switch (mdev->type) {
	case G200_SE_A:
	case G200_SE_B:
		dacvalue[MGA1064_VREF_CTL] = 0x03;
		dacvalue[MGA1064_PIX_CLK_CTL] = MGA1064_PIX_CLK_CTL_SEL_PLL;
		dacvalue[MGA1064_MISC_CTL] = MGA1064_MISC_CTL_DAC_EN |
					     MGA1064_MISC_CTL_VGA8 |
					     MGA1064_MISC_CTL_DAC_RAM_CS;
		if (mdev->has_sdram)
			option = 0x40049120;
		else
			option = 0x4004d120;
		option2 = 0x00008000;
		break;
	case G200_WB:
	case G200_EW3:
		dacvalue[MGA1064_VREF_CTL] = 0x07;
		option = 0x41049120;
		option2 = 0x0000b000;
		break;
	case G200_EV:
		dacvalue[MGA1064_PIX_CLK_CTL] = MGA1064_PIX_CLK_CTL_SEL_PLL;
		dacvalue[MGA1064_MISC_CTL] = MGA1064_MISC_CTL_VGA8 |
					     MGA1064_MISC_CTL_DAC_RAM_CS;
		option = 0x00000120;
		option2 = 0x0000b000;
		break;
	case G200_EH:
	case G200_EH3:
		dacvalue[MGA1064_MISC_CTL] = MGA1064_MISC_CTL_VGA8 |
					     MGA1064_MISC_CTL_DAC_RAM_CS;
		option = 0x00000120;
		option2 = 0x0000b000;
		break;
	case G200_ER:
		break;
	}

	for (i = 0; i < sizeof(dacvalue); i++) {
		if ((i <= 0x17) ||
		    (i == 0x1b) ||
		    (i == 0x1c) ||
		    ((i >= 0x1f) && (i <= 0x29)) ||
		    ((i >= 0x30) && (i <= 0x37)))
			continue;
		if (IS_G200_SE(mdev) &&
		    ((i == 0x2c) || (i == 0x2d) || (i == 0x2e)))
			continue;
		if ((mdev->type == G200_EV ||
		    mdev->type == G200_WB ||
		    mdev->type == G200_EH ||
		    mdev->type == G200_EW3 ||
		    mdev->type == G200_EH3) &&
		    (i >= 0x44) && (i <= 0x4e))
			continue;

		WREG_DAC(i, dacvalue[i]);
	}

	if (mdev->type == G200_ER)
		WREG_DAC(0x90, 0);

	if (option)
		pci_write_config_dword(dev->pdev, PCI_MGA_OPTION, option);
	if (option2)
		pci_write_config_dword(dev->pdev, PCI_MGA_OPTION2, option2);

	WREG_SEQ(2, 0xf);
	WREG_SEQ(3, 0);
	WREG_SEQ(4, 0xe);

	WREG_CRT(10, 0);
	WREG_CRT(11, 0);
	WREG_CRT(12, 0);
	WREG_CRT(13, 0);
	WREG_CRT(14, 0);
	WREG_CRT(15, 0);

	RREG_ECRT(0x03, crtcext3);

	crtcext3 |= BIT(7); /* enable MGA mode */
	crtcext4 = 0x00;

	WREG_ECRT(0x03, crtcext3);
	WREG_ECRT(0x04, crtcext4);

	if (mdev->type == G200_ER)
		WREG_ECRT(0x24, 0x5);

	if (mdev->type == G200_EW3)
		WREG_ECRT(0x34, 0x5);

	misc = RREG8(MGA_MISC_IN);
	misc |= MGAREG_MISC_IOADSEL |
		MGAREG_MISC_RAMMAPEN |
		MGAREG_MISC_HIGH_PG_SEL;
	WREG8(MGA_MISC_OUT, misc);

	mgag200_set_format_regs(mdev, fb);
	mga_crtc_do_set_base(mdev, fb, old_fb);
	mgag200_set_offset(mdev, fb);

	mgag200_set_mode_regs(mdev, mode);

	if (mdev->type == G200_ER)
		mgag200_g200er_reset_tagfifo(mdev);

	if (IS_G200_SE(mdev))
		mgag200_g200se_set_hiprilvl(mdev, mode, fb);
	else if (mdev->type == G200_EV)
		mgag200_g200ev_set_hiprilvl(mdev);

	return 0;
}

#if 0 /* code from mjg to attempt D3 on crtc dpms off - revisit later */
static int mga_suspend(struct drm_crtc *crtc)
{
	struct mga_crtc *mga_crtc = to_mga_crtc(crtc);
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = dev->dev_private;
	struct pci_dev *pdev = dev->pdev;
	int option;

	if (mdev->suspended)
		return 0;

	WREG_SEQ(1, 0x20);
	WREG_ECRT(1, 0x30);
	/* Disable the pixel clock */
	WREG_DAC(0x1a, 0x05);
	/* Power down the DAC */
	WREG_DAC(0x1e, 0x18);
	/* Power down the pixel PLL */
	WREG_DAC(0x1a, 0x0d);

	/* Disable PLLs and clocks */
	pci_read_config_dword(pdev, PCI_MGA_OPTION, &option);
	option &= ~(0x1F8024);
	pci_write_config_dword(pdev, PCI_MGA_OPTION, option);
	pci_set_power_state(pdev, PCI_D3hot);
	pci_disable_device(pdev);

	mdev->suspended = true;

	return 0;
}

static int mga_resume(struct drm_crtc *crtc)
{
	struct mga_crtc *mga_crtc = to_mga_crtc(crtc);
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = dev->dev_private;
	struct pci_dev *pdev = dev->pdev;
	int option;

	if (!mdev->suspended)
		return 0;

	pci_set_power_state(pdev, PCI_D0);
	pci_enable_device(pdev);

	/* Disable sysclk */
	pci_read_config_dword(pdev, PCI_MGA_OPTION, &option);
	option &= ~(0x4);
	pci_write_config_dword(pdev, PCI_MGA_OPTION, option);

	mdev->suspended = false;

	return 0;
}

#endif

static void mga_crtc_dpms(struct drm_crtc *crtc, int mode)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = to_mga_device(dev);
	u8 seq1 = 0, crtcext1 = 0;

	switch (mode) {
	case DRM_MODE_DPMS_ON:
		seq1 = 0;
		crtcext1 = 0;
		mga_crtc_load_lut(crtc);
		break;
	case DRM_MODE_DPMS_STANDBY:
		seq1 = 0x20;
		crtcext1 = 0x10;
		break;
	case DRM_MODE_DPMS_SUSPEND:
		seq1 = 0x20;
		crtcext1 = 0x20;
		break;
	case DRM_MODE_DPMS_OFF:
		seq1 = 0x20;
		crtcext1 = 0x30;
		break;
	}

#if 0
	if (mode == DRM_MODE_DPMS_OFF) {
		mga_suspend(crtc);
	}
#endif
	WREG8(MGAREG_SEQ_INDEX, 0x01);
	seq1 |= RREG8(MGAREG_SEQ_DATA) & ~0x20;
	mga_wait_vsync(mdev);
	mga_wait_busy(mdev);
	WREG8(MGAREG_SEQ_DATA, seq1);
	msleep(20);
	WREG8(MGAREG_CRTCEXT_INDEX, 0x01);
	crtcext1 |= RREG8(MGAREG_CRTCEXT_DATA) & ~0x30;
	WREG8(MGAREG_CRTCEXT_DATA, crtcext1);

#if 0
	if (mode == DRM_MODE_DPMS_ON && mdev->suspended == true) {
		mga_resume(crtc);
		drm_helper_resume_force_mode(dev);
	}
#endif
}

/*
 * This is called before a mode is programmed. A typical use might be to
 * enable DPMS during the programming to avoid seeing intermediate stages,
 * but that's not relevant to us
 */
static void mga_crtc_prepare(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = to_mga_device(dev);
	u8 tmp;

	/*	mga_resume(crtc);*/

	WREG8(MGAREG_CRTC_INDEX, 0x11);
	tmp = RREG8(MGAREG_CRTC_DATA);
	WREG_CRT(0x11, tmp | 0x80);

	if (mdev->type == G200_SE_A || mdev->type == G200_SE_B) {
		WREG_SEQ(0, 1);
		msleep(50);
		WREG_SEQ(1, 0x20);
		msleep(20);
	} else {
		WREG8(MGAREG_SEQ_INDEX, 0x1);
		tmp = RREG8(MGAREG_SEQ_DATA);

		/* start sync reset */
		WREG_SEQ(0, 1);
		WREG_SEQ(1, tmp | 0x20);
	}

	if (mdev->type == G200_WB || mdev->type == G200_EW3)
		mga_g200wb_prepare(crtc);

	WREG_CRT(17, 0);
}

/*
 * This is called after a mode is programmed. It should reverse anything done
 * by the prepare function
 */
static void mga_crtc_commit(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;
	struct mga_device *mdev = to_mga_device(dev);
	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
	u8 tmp;

	if (mdev->type == G200_WB || mdev->type == G200_EW3)
		mga_g200wb_commit(crtc);

	if (mdev->type == G200_SE_A || mdev->type == G200_SE_B) {
		msleep(50);
		WREG_SEQ(1, 0x0);
		msleep(20);
		WREG_SEQ(0, 0x3);
	} else {
		WREG8(MGAREG_SEQ_INDEX, 0x1);
		tmp = RREG8(MGAREG_SEQ_DATA);

		tmp &= ~0x20;
		WREG_SEQ(0x1, tmp);
		WREG_SEQ(0, 3);
	}
	crtc_funcs->dpms(crtc, DRM_MODE_DPMS_ON);
}

/*
 * The core can pass us a set of gamma values to program. We actually only
 * use this for 8-bit mode so can't perform smooth fades on deeper modes,
 * but it's a requirement that we provide the function
 */
static int mga_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
			      u16 *blue, uint32_t size,
			      struct drm_modeset_acquire_ctx *ctx)
{
	mga_crtc_load_lut(crtc);

	return 0;
}

/* Simple cleanup function */
static void mga_crtc_destroy(struct drm_crtc *crtc)
{
	struct mga_crtc *mga_crtc = to_mga_crtc(crtc);

	drm_crtc_cleanup(crtc);
	kfree(mga_crtc);
}

static void mga_crtc_disable(struct drm_crtc *crtc)
{
	DRM_DEBUG_KMS("\n");
	mga_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
	if (crtc->primary->fb) {
		struct drm_framebuffer *fb = crtc->primary->fb;
		struct drm_gem_vram_object *gbo =
			drm_gem_vram_of_gem(fb->obj[0]);
		drm_gem_vram_unpin(gbo);
	}
	crtc->primary->fb = NULL;
}

/* These provide the minimum set of functions required to handle a CRTC */
static const struct drm_crtc_funcs mga_crtc_funcs = {
	.gamma_set = mga_crtc_gamma_set,
	.set_config = drm_crtc_helper_set_config,
	.destroy = mga_crtc_destroy,
};

static const struct drm_crtc_helper_funcs mga_helper_funcs = {
	.disable = mga_crtc_disable,
	.dpms = mga_crtc_dpms,
	.mode_set = mga_crtc_mode_set,
	.mode_set_base = mga_crtc_mode_set_base,
	.prepare = mga_crtc_prepare,
	.commit = mga_crtc_commit,
};

/* CRTC setup */
static void mga_crtc_init(struct mga_device *mdev)
{
	struct drm_device *dev = mdev->dev;
	struct mga_crtc *mga_crtc;

	mga_crtc = kzalloc(sizeof(struct mga_crtc) +
			      (MGAG200FB_CONN_LIMIT * sizeof(struct drm_connector *)),
			      GFP_KERNEL);

	if (mga_crtc == NULL)
		return;

	drm_crtc_init(dev, &mga_crtc->base, &mga_crtc_funcs);

	drm_mode_crtc_set_gamma_size(&mga_crtc->base, MGAG200_LUT_SIZE);

	drm_crtc_helper_add(&mga_crtc->base, &mga_helper_funcs);
}

/*
 * Connector
 */

static int mga_vga_get_modes(struct drm_connector *connector)
{
	struct mga_connector *mga_connector = to_mga_connector(connector);
	struct edid *edid;
	int ret = 0;

	edid = drm_get_edid(connector, &mga_connector->i2c->adapter);
	if (edid) {
		drm_connector_update_edid_property(connector, edid);
		ret = drm_add_edid_modes(connector, edid);
		kfree(edid);
	}
	return ret;
}

static uint32_t mga_vga_calculate_mode_bandwidth(struct drm_display_mode *mode,
							int bits_per_pixel)
{
	uint32_t total_area, divisor;
	uint64_t active_area, pixels_per_second, bandwidth;
	uint64_t bytes_per_pixel = (bits_per_pixel + 7) / 8;

	divisor = 1024;

	if (!mode->htotal || !mode->vtotal || !mode->clock)
		return 0;

	active_area = mode->hdisplay * mode->vdisplay;
	total_area = mode->htotal * mode->vtotal;

	pixels_per_second = active_area * mode->clock * 1000;
	do_div(pixels_per_second, total_area);

	bandwidth = pixels_per_second * bytes_per_pixel * 100;
	do_div(bandwidth, divisor);

	return (uint32_t)(bandwidth);
}

#define MODE_BANDWIDTH	MODE_BAD

static enum drm_mode_status mga_vga_mode_valid(struct drm_connector *connector,
				 struct drm_display_mode *mode)
{
	struct drm_device *dev = connector->dev;
	struct mga_device *mdev = to_mga_device(dev);
	int bpp = 32;

	if (IS_G200_SE(mdev)) {
		if (mdev->unique_rev_id == 0x01) {
			if (mode->hdisplay > 1600)
				return MODE_VIRTUAL_X;
			if (mode->vdisplay > 1200)
				return MODE_VIRTUAL_Y;
			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
				> (24400 * 1024))
				return MODE_BANDWIDTH;
		} else if (mdev->unique_rev_id == 0x02) {
			if (mode->hdisplay > 1920)
				return MODE_VIRTUAL_X;
			if (mode->vdisplay > 1200)
				return MODE_VIRTUAL_Y;
			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
				> (30100 * 1024))
				return MODE_BANDWIDTH;
		} else {
			if (mga_vga_calculate_mode_bandwidth(mode, bpp)
				> (55000 * 1024))
				return MODE_BANDWIDTH;
		}
	} else if (mdev->type == G200_WB) {
		if (mode->hdisplay > 1280)
			return MODE_VIRTUAL_X;
		if (mode->vdisplay > 1024)
			return MODE_VIRTUAL_Y;
		if (mga_vga_calculate_mode_bandwidth(mode, bpp) >
		    (31877 * 1024))
			return MODE_BANDWIDTH;
	} else if (mdev->type == G200_EV &&
		(mga_vga_calculate_mode_bandwidth(mode, bpp)
			> (32700 * 1024))) {
		return MODE_BANDWIDTH;
	} else if (mdev->type == G200_EH &&
		(mga_vga_calculate_mode_bandwidth(mode, bpp)
			> (37500 * 1024))) {
		return MODE_BANDWIDTH;
	} else if (mdev->type == G200_ER &&
		(mga_vga_calculate_mode_bandwidth(mode,
			bpp) > (55000 * 1024))) {
		return MODE_BANDWIDTH;
	}

	if ((mode->hdisplay % 8) != 0 || (mode->hsync_start % 8) != 0 ||
	    (mode->hsync_end % 8) != 0 || (mode->htotal % 8) != 0) {
		return MODE_H_ILLEGAL;
	}

	if (mode->crtc_hdisplay > 2048 || mode->crtc_hsync_start > 4096 ||
	    mode->crtc_hsync_end > 4096 || mode->crtc_htotal > 4096 ||
	    mode->crtc_vdisplay > 2048 || mode->crtc_vsync_start > 4096 ||
	    mode->crtc_vsync_end > 4096 || mode->crtc_vtotal > 4096) {
		return MODE_BAD;
	}

	/* Validate the mode input by the user */
	if (connector->cmdline_mode.specified) {
		if (connector->cmdline_mode.bpp_specified)
			bpp = connector->cmdline_mode.bpp;
	}

	if ((mode->hdisplay * mode->vdisplay * (bpp/8)) > mdev->vram_fb_available) {
		if (connector->cmdline_mode.specified)
			connector->cmdline_mode.specified = false;
		return MODE_BAD;
	}

	return MODE_OK;
}

static void mga_connector_destroy(struct drm_connector *connector)
{
	struct mga_connector *mga_connector = to_mga_connector(connector);
	mgag200_i2c_destroy(mga_connector->i2c);
	drm_connector_cleanup(connector);
}

static const struct drm_connector_helper_funcs mga_vga_connector_helper_funcs = {
	.get_modes = mga_vga_get_modes,
	.mode_valid = mga_vga_mode_valid,
};

static const struct drm_connector_funcs mga_vga_connector_funcs = {
	.dpms = drm_helper_connector_dpms,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.destroy = mga_connector_destroy,
};

static int mgag200_vga_connector_init(struct mga_device *mdev)
{
	struct drm_device *dev = mdev->dev;
	struct mga_connector *mconnector = &mdev->connector;
	struct drm_connector *connector = &mconnector->base;
	struct mga_i2c_chan *i2c;
	int ret;

	i2c = mgag200_i2c_create(dev);
	if (!i2c)
		drm_warn(dev, "failed to add DDC bus\n");

	ret = drm_connector_init_with_ddc(dev, connector,
					  &mga_vga_connector_funcs,
					  DRM_MODE_CONNECTOR_VGA,
					  &i2c->adapter);
	if (ret)
		goto err_mgag200_i2c_destroy;
	drm_connector_helper_add(connector, &mga_vga_connector_helper_funcs);

	mconnector->i2c = i2c;

	return 0;

err_mgag200_i2c_destroy:
	mgag200_i2c_destroy(i2c);
	return ret;
}

static const struct drm_mode_config_funcs mgag200_mode_config_funcs = {
	.fb_create = drm_gem_fb_create
};

static unsigned int mgag200_preferred_depth(struct mga_device *mdev)
{
	if (IS_G200_SE(mdev) && mdev->vram_fb_available < (2048*1024))
		return 16;
	else
		return 32;
}

int mgag200_modeset_init(struct mga_device *mdev)
{
	struct drm_device *dev = mdev->dev;
	struct drm_encoder *encoder = &mdev->encoder;
	struct drm_connector *connector = &mdev->connector.base;
	int ret;

	mdev->bpp_shifts[0] = 0;
	mdev->bpp_shifts[1] = 1;
	mdev->bpp_shifts[2] = 0;
	mdev->bpp_shifts[3] = 2;

	ret = drmm_mode_config_init(dev);
	if (ret) {
		drm_err(dev, "drmm_mode_config_init() failed, error %d\n",
			ret);
		return ret;
	}

	dev->mode_config.max_width = MGAG200_MAX_FB_WIDTH;
	dev->mode_config.max_height = MGAG200_MAX_FB_HEIGHT;

	dev->mode_config.preferred_depth = mgag200_preferred_depth(mdev);
	dev->mode_config.prefer_shadow = 1;

	dev->mode_config.fb_base = mdev->mc.vram_base;

	dev->mode_config.funcs = &mgag200_mode_config_funcs;

	mga_crtc_init(mdev);

	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_DAC);
	if (ret) {
		drm_err(dev,
			"drm_simple_encoder_init() failed, error %d\n",
			ret);
		return ret;
	}
	encoder->possible_crtcs = 0x1;

	ret = mgag200_vga_connector_init(mdev);
	if (ret) {
		drm_err(dev,
			"mgag200_vga_connector_init() failed, error %d\n",
			ret);
		return ret;
	}

	drm_connector_attach_encoder(connector, encoder);

	return 0;
}