src/northbridge/intel/i945/gma.c

/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */

#include <console/console.h>
#include <bootmode.h>
#include <device/mmio.h>
#include <delay.h>
#include <arch/io.h>
#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ops.h>
#include <device/pci_ids.h>
#include <option.h>
#include <edid.h>
#include <drivers/intel/gma/edid.h>
#include <drivers/intel/gma/i915.h>
#include <drivers/intel/gma/opregion.h>
#include <string.h>
#include <pc80/vga.h>
#include <pc80/vga_io.h>
#include <commonlib/helpers.h>
#include <cbmem.h>
#include <southbridge/intel/i82801gx/nvs.h>
#include <types.h>

#include "i945.h"
#include "chip.h"

#define GDRST 0xc0
#define MSAC 0x62 /* Multi Size Aperture Control */

#define  LVDS_CLOCK_A_POWERUP_ALL	(3 << 8)
#define  LVDS_CLOCK_B_POWERUP_ALL	(3 << 4)
#define  LVDS_CLOCK_BOTH_POWERUP_ALL	(3 << 2)

#define   DPLLB_LVDS_P2_CLOCK_DIV_7	(1 << 24) /* i915 */

#define   DPLL_INTEGRATED_CRI_CLK_VLV	(1 << 14)

#define PGETBL_CTL	0x2020
#define PGETBL_ENABLED	0x00000001

#define BASE_FREQUENCY 100000

#define DEFAULT_BLC_PWM 180

uintptr_t gma_get_gnvs_aslb(const void *gnvs)
{
	const global_nvs_t *gnvs_ptr = gnvs;
	return (uintptr_t)(gnvs_ptr ? gnvs_ptr->aslb : 0);
}

void gma_set_gnvs_aslb(void *gnvs, uintptr_t aslb)
{
	global_nvs_t *gnvs_ptr = gnvs;
	if (gnvs_ptr)
		gnvs_ptr->aslb = aslb;
}

static int gtt_setup(u8 *mmiobase)
{
	unsigned long PGETBL_save;
	unsigned long tom; // top of memory

	/*
	 * The Video BIOS places the GTT right below top of memory.
	 */
	tom = pci_read_config8(pcidev_on_root(0, 0), TOLUD) << 24;
	PGETBL_save = tom - 256 * KiB;
	PGETBL_save |= PGETBL_ENABLED;
	PGETBL_save |= 2; /* set GTT to 256kb */

	write32(mmiobase + GFX_FLSH_CNTL, 0);

	write32(mmiobase + PGETBL_CTL, PGETBL_save);

	/* verify */
	if (read32(mmiobase + PGETBL_CTL) & PGETBL_ENABLED) {
		printk(BIOS_DEBUG, "%s is enabled.\n", __func__);
	} else {
		printk(BIOS_DEBUG, "%s failed!!!\n", __func__);
		return 1;
	}
	write32(mmiobase + GFX_FLSH_CNTL, 0);

	return 0;
}

static int intel_gma_init_lvds(struct northbridge_intel_i945_config *conf,
			  unsigned int pphysbase, unsigned int piobase,
			  u8 *mmiobase, unsigned int pgfx)
{
	struct edid edid;
	struct edid_mode *mode;
	u8 edid_data[128];
	unsigned long temp;
	int hpolarity, vpolarity;
	u32 smallest_err = 0xffffffff;
	u32 target_frequency;
	u32 pixel_p1 = 1;
	u32 pixel_p2;
	u32 pixel_n = 1;
	u32 pixel_m1 = 1;
	u32 pixel_m2 = 1;
	u32 hactive, vactive, right_border, bottom_border;
	u32 vsync, hsync, vblank, hblank, hfront_porch, vfront_porch;
	u32 i, j;
	u32 uma_size;
	u16 reg16;

	printk(BIOS_SPEW,
	       "i915lightup: graphics %p mmio %p addrport %04x physbase %08x\n",
	       (void *)pgfx, mmiobase, piobase, pphysbase);

	intel_gmbus_read_edid(mmiobase + GMBUS0, GMBUS_PORT_PANEL, 0x50,
			edid_data, sizeof(edid_data));
	decode_edid(edid_data, sizeof(edid_data), &edid);
	mode = &edid.mode;

	hpolarity = (mode->phsync == '-');
	vpolarity = (mode->pvsync == '-');
	hactive = edid.x_resolution;
	vactive = edid.y_resolution;
	right_border = mode->hborder;
	bottom_border = mode->vborder;
	vblank = mode->vbl;
	hblank = mode->hbl;
	vsync = mode->vspw;
	hsync = mode->hspw;
	hfront_porch = mode->hso;
	vfront_porch = mode->vso;

	for (i = 0; i < 2; i++)
		for (j = 0; j < 0x100; j++)
			/* R = j, G = j, B = j.  */
			write32(mmiobase + PALETTE(i) + 4 * j, 0x10101 * j);

	write32(mmiobase + PCH_PP_CONTROL, PANEL_UNLOCK_REGS
		| (read32(mmiobase + PCH_PP_CONTROL) & ~PANEL_UNLOCK_MASK));

	write32(mmiobase + MI_ARB_STATE, MI_ARB_C3_LP_WRITE_ENABLE | (1 << 27));
	/* Clean registers.  */
	for (i = 0; i < 0x20; i += 4)
		write32(mmiobase + RENDER_RING_BASE + i, 0);
	for (i = 0; i < 0x20; i += 4)
		write32(mmiobase + FENCE_REG_965_0 + i, 0);

	/* Disable VGA.  */
	write32(mmiobase + VGACNTRL, VGA_DISP_DISABLE);

	/* Disable pipes.  */
	write32(mmiobase + PIPECONF(0), 0);
	write32(mmiobase + PIPECONF(1), 0);

	/* Init PRB0.  */
	write32(mmiobase + HWS_PGA, 0x352d2000);
	write32(mmiobase + PRB0_CTL, 0);
	write32(mmiobase + PRB0_HEAD, 0);
	write32(mmiobase + PRB0_TAIL, 0);
	write32(mmiobase + PRB0_START, 0);
	write32(mmiobase + PRB0_CTL, 0x0001f001);

	write32(mmiobase + D_STATE, DSTATE_PLL_D3_OFF
		| DSTATE_GFX_CLOCK_GATING | DSTATE_DOT_CLOCK_GATING);
	write32(mmiobase + ECOSKPD, 0x00010000);
	write32(mmiobase + HWSTAM, 0xeffe);
	write32(mmiobase + PORT_HOTPLUG_EN, conf->gpu_hotplug);
	write32(mmiobase + INSTPM, 0x08000000 | INSTPM_AGPBUSY_DIS);

	/* p2 divisor must 7 for dual channel LVDS */
	/* and 14 for single channel LVDS */
	pixel_p2 = mode->lvds_dual_channel ? 7 : 14;
	target_frequency = mode->pixel_clock;

	/* Find suitable divisors, m1, m2, p1, n.  */
	/* refclock * (5 * (m1 + 2) + (m1 + 2)) / (n + 2) / p1 / p2 */
	/* should be closest to target frequency as possible */
	u32 candn, candm1, candm2, candp1;
	for (candm1 = 8; candm1 <= 18; candm1++) {
		for (candm2 = 3; candm2 <= 7; candm2++) {
			for (candn = 1; candn <= 6; candn++) {
				for (candp1 = 1; candp1 <= 8; candp1++) {
					u32 m = 5 * (candm1 + 2) + (candm2 + 2);
					u32 p = candp1 * pixel_p2;
					u32 vco = DIV_ROUND_CLOSEST(BASE_FREQUENCY * m, candn + 2);
					u32 dot = DIV_ROUND_CLOSEST(vco, p);
					u32 this_err = MAX(dot, target_frequency) -
						MIN(dot, target_frequency);
					if ((m < 70) || (m > 120))
						continue;
					if (this_err < smallest_err) {
						smallest_err = this_err;
						pixel_n = candn;
						pixel_m1 = candm1;
						pixel_m2 = candm2;
						pixel_p1 = candp1;
					}
				}
			}
		}
	}

	if (smallest_err == 0xffffffff) {
		printk(BIOS_ERR, "Couldn't find GFX clock divisors\n");
		return -1;
	}

	printk(BIOS_INFO, "bringing up panel at resolution %d x %d\n",
	       hactive, vactive);
	printk(BIOS_DEBUG, "Borders %d x %d\n", right_border, bottom_border);
	printk(BIOS_DEBUG, "Blank %d x %d\n", hblank, vblank);
	printk(BIOS_DEBUG, "Sync %d x %d\n", hsync, vsync);
	printk(BIOS_DEBUG, "Front porch %d x %d\n", hfront_porch, vfront_porch);
	printk(BIOS_DEBUG, (conf->gpu_lvds_use_spread_spectrum_clock
			    ? "Spread spectrum clock\n"
			    : "DREF clock\n"));
	printk(BIOS_DEBUG, (mode->lvds_dual_channel
			    ? "Dual channel\n"
			    : "Single channel\n"));
	printk(BIOS_DEBUG, "Polarities %d, %d\n",
	       hpolarity, vpolarity);
	printk(BIOS_DEBUG, "Pixel N=%d, M1=%d, M2=%d, P1=%d\n",
	       pixel_n, pixel_m1, pixel_m2, pixel_p1);
	printk(BIOS_DEBUG, "Pixel clock %d kHz\n",
	       BASE_FREQUENCY * (5 * (pixel_m1 + 2) + (pixel_m2 + 2)) /
	       (pixel_n + 2) / (pixel_p1 * pixel_p2));

	printk(BIOS_INFO, "VGA mode: %s\n", CONFIG(LINEAR_FRAMEBUFFER) ?
	       "Linear framebuffer" : "text");
	if (CONFIG(LINEAR_FRAMEBUFFER)) {
		/* Disable panel fitter (we're in native resolution). */
		write32(mmiobase + PF_CTL(0), 0);
		write32(mmiobase + PF_WIN_SZ(0), 0);
		write32(mmiobase + PF_WIN_POS(0), 0);
		write32(mmiobase + PFIT_PGM_RATIOS, 0);
		write32(mmiobase + PFIT_CONTROL, 0);
	} else {
		write32(mmiobase + PF_WIN_SZ(0), vactive | (hactive << 16));
		write32(mmiobase + PF_WIN_POS(0), 0);
		write32(mmiobase + PF_CTL(0), PF_ENABLE | PF_FILTER_MED_3x3);
		write32(mmiobase + PFIT_CONTROL, PFIT_ENABLE
			| (1 << PFIT_PIPE_SHIFT) | HORIZ_AUTO_SCALE
			| VERT_AUTO_SCALE);
	}

	mdelay(1);

	write32(mmiobase + DSPCNTR(0), DISPPLANE_BGRX888
		| DISPPLANE_SEL_PIPE_B | DISPPLANE_GAMMA_ENABLE);

	mdelay(1);
	write32(mmiobase + PP_CONTROL, PANEL_UNLOCK_REGS
		| (read32(mmiobase + PP_CONTROL) & ~PANEL_UNLOCK_MASK));
	write32(mmiobase + FP0(1),
		(pixel_n << 16)
		| (pixel_m1 << 8) | pixel_m2);
	write32(mmiobase + DPLL(1),
		DPLL_VGA_MODE_DIS |
		DPLL_VCO_ENABLE | DPLLB_MODE_LVDS
		| (mode->lvds_dual_channel ? DPLLB_LVDS_P2_CLOCK_DIV_7
		   : DPLLB_LVDS_P2_CLOCK_DIV_14)
		| (conf->gpu_lvds_use_spread_spectrum_clock
		   ? DPLL_INTEGRATED_CLOCK_VLV | DPLL_INTEGRATED_CRI_CLK_VLV
		   : 0)
		| (0x10000 << (pixel_p1 - 1)));
	mdelay(1);
	write32(mmiobase + DPLL(1),
		DPLL_VGA_MODE_DIS |
		DPLL_VCO_ENABLE | DPLLB_MODE_LVDS
		| (mode->lvds_dual_channel ? DPLLB_LVDS_P2_CLOCK_DIV_7
		   : DPLLB_LVDS_P2_CLOCK_DIV_14)
		| ((conf->gpu_lvds_use_spread_spectrum_clock ? 3 : 0) << 13)
		| (0x10000 << (pixel_p1 - 1)));
	mdelay(1);
	write32(mmiobase + HTOTAL(1),
		((hactive + right_border + hblank - 1) << 16)
		| (hactive - 1));
	write32(mmiobase + HBLANK(1),
		((hactive + right_border + hblank - 1) << 16)
		| (hactive + right_border - 1));
	write32(mmiobase + HSYNC(1),
		((hactive + right_border + hfront_porch + hsync - 1) << 16)
		| (hactive + right_border + hfront_porch - 1));

	write32(mmiobase + VTOTAL(1), ((vactive + bottom_border + vblank - 1) << 16)
		| (vactive - 1));
	write32(mmiobase + VBLANK(1), ((vactive + bottom_border + vblank - 1) << 16)
		| (vactive + bottom_border - 1));
	write32(mmiobase + VSYNC(1),
		((vactive + bottom_border + vfront_porch + vsync - 1) << 16)
		| (vactive + bottom_border + vfront_porch - 1));

	if (CONFIG(LINEAR_FRAMEBUFFER)) {
		write32(mmiobase + PIPESRC(1), ((hactive - 1) << 16)
			| (vactive - 1));
	} else {
		write32(mmiobase + PIPESRC(1), (639 << 16) | 399);
	}

	mdelay(1);

	write32(mmiobase + DSPSIZE(0), (hactive - 1) | ((vactive - 1) << 16));
	write32(mmiobase + DSPPOS(0), 0);

	edid.bytes_per_line = (edid.bytes_per_line + 63) & ~63;
	write32(mmiobase + DSPADDR(0), 0);
	write32(mmiobase + DSPSURF(0), 0);
	write32(mmiobase + DSPSTRIDE(0), edid.bytes_per_line);
	write32(mmiobase + DSPCNTR(0), DISPLAY_PLANE_ENABLE | DISPPLANE_BGRX888
		| DISPPLANE_SEL_PIPE_B | DISPPLANE_GAMMA_ENABLE);
	mdelay(1);

	write32(mmiobase + PIPECONF(1), PIPECONF_ENABLE);
	write32(mmiobase + LVDS, LVDS_ON
		| (hpolarity << 20) | (vpolarity << 21)
		| (mode->lvds_dual_channel ? LVDS_CLOCK_B_POWERUP_ALL
		   | LVDS_CLOCK_BOTH_POWERUP_ALL : 0)
		| LVDS_CLOCK_A_POWERUP_ALL
		| LVDS_PIPE(1));

	write32(mmiobase + PP_CONTROL, PANEL_UNLOCK_REGS | PANEL_POWER_OFF);
	write32(mmiobase + PP_CONTROL, PANEL_UNLOCK_REGS | PANEL_POWER_RESET);
	mdelay(1);
	write32(mmiobase + PP_CONTROL, PANEL_UNLOCK_REGS
		| PANEL_POWER_ON | PANEL_POWER_RESET);

	printk(BIOS_DEBUG, "waiting for panel powerup\n");
	while (1) {
		u32 reg32;
		reg32 = read32(mmiobase + PP_STATUS);
		if ((reg32 & PP_SEQUENCE_MASK) == PP_SEQUENCE_NONE)
			break;
	}
	printk(BIOS_DEBUG, "panel powered up\n");

	write32(mmiobase + PP_CONTROL, PANEL_POWER_ON | PANEL_POWER_RESET);

	/* Clear interrupts. */
	write32(mmiobase + DEIIR, 0xffffffff);
	write32(mmiobase + SDEIIR, 0xffffffff);
	write32(mmiobase + IIR, 0xffffffff);
	write32(mmiobase + IMR, 0xffffffff);
	write32(mmiobase + EIR, 0xffffffff);

	if (gtt_setup(mmiobase)) {
		printk(BIOS_ERR, "ERROR: GTT Setup Failed!!!\n");
		return 0;
	}

	/* Setup GTT.  */

	reg16 = pci_read_config16(pcidev_on_root(0, 0), GGC);
	uma_size = 0;
	if (!(reg16 & 2)) {
		uma_size = decode_igd_memory_size((reg16 >> 4) & 7);
		printk(BIOS_DEBUG, "%dM UMA\n", uma_size >> 10);
	}

	for (i = 0; i < (uma_size - 256) / 4; i++) {
		outl((i << 2) | 1, piobase);
		outl(pphysbase + (i << 12) + 1, piobase + 4);
	}

	temp = read32(mmiobase + PGETBL_CTL);
	printk(BIOS_INFO, "GTT PGETBL_CTL register: 0x%lx\n", temp);

	if (temp & 1)
		printk(BIOS_INFO, "GTT Enabled\n");
	else
		printk(BIOS_ERR, "ERROR: GTT is still Disabled!!!\n");

	if (CONFIG(LINEAR_FRAMEBUFFER)) {
		printk(BIOS_SPEW, "memset %p to 0x00 for %d bytes\n",
			(void *)pgfx, hactive * vactive * 4);
		memset((void *)pgfx, 0x00, hactive * vactive * 4);

		set_vbe_mode_info_valid(&edid, pgfx);
	} else {
			vga_misc_write(0x67);

			write32(mmiobase + DSPCNTR(0), DISPPLANE_SEL_PIPE_B);
			write32(mmiobase + VGACNTRL, 0x02c4008e
				| VGA_PIPE_B_SELECT);

			vga_textmode_init();
	}
	return 0;
}

static int intel_gma_init_vga(struct northbridge_intel_i945_config *conf,
			  unsigned int pphysbase, unsigned int piobase,
			  u8 *mmiobase, unsigned int pgfx)
{
	int i;
	u32 hactive, vactive;
	u16 reg16;
	u32 uma_size;

	printk(BIOS_SPEW, "mmiobase %x addrport %x physbase %x\n",
		(u32)mmiobase, piobase, pphysbase);

	gtt_setup(mmiobase);

	/* Disable VGA.  */
	write32(mmiobase + VGACNTRL, VGA_DISP_DISABLE);

	/* Disable pipes.  */
	write32(mmiobase + PIPECONF(0), 0);
	write32(mmiobase + PIPECONF(1), 0);

	write32(mmiobase + INSTPM, 0x800);

	vga_gr_write(0x18, 0);

	write32(mmiobase + VGA0, 0x200074);
	write32(mmiobase + VGA1, 0x200074);

	write32(mmiobase + DSPFW3, 0x7f3f00c1 & ~PINEVIEW_SELF_REFRESH_EN);
	write32(mmiobase + DSPCLK_GATE_D, 0);
	write32(mmiobase + FW_BLC, 0x03060106);
	write32(mmiobase + FW_BLC2, 0x00000306);

	write32(mmiobase + ADPA, ADPA_DAC_ENABLE
			| ADPA_PIPE_A_SELECT
			| ADPA_USE_VGA_HVPOLARITY
			| ADPA_VSYNC_CNTL_ENABLE
			| ADPA_HSYNC_CNTL_ENABLE
			| ADPA_DPMS_ON
			);

	write32(mmiobase + 0x7041c, 0x0);

	write32(mmiobase + DPLL_MD(0), 0x3);
	write32(mmiobase + DPLL_MD(1), 0x3);
	write32(mmiobase + DSPCNTR(1), 0x1000000);
	write32(mmiobase + PIPESRC(1), 0x027f01df);

	vga_misc_write(0x67);
	const u8 cr[] = { 0x5f, 0x4f, 0x50, 0x82, 0x55, 0x81, 0xbf, 0x1f,
		    0x00, 0x4f, 0x0d, 0x0e, 0x00, 0x00, 0x00, 0x00,
		    0x9c, 0x8e, 0x8f, 0x28, 0x1f, 0x96, 0xb9, 0xa3,
		    0xff
	};
	vga_cr_write(0x11, 0);

	for (i = 0; i <= 0x18; i++)
		vga_cr_write(i, cr[i]);

	// Disable screen memory to prevent garbage from appearing.
	vga_sr_write(1, vga_sr_read(1) | 0x20);
	hactive = 640;
	vactive = 400;

	mdelay(1);
	write32(mmiobase + DPLL(0),
		DPLL_VCO_ENABLE | DPLLB_MODE_DAC_SERIAL
		| DPLL_VGA_MODE_DIS
		| DPLL_DAC_SERIAL_P2_CLOCK_DIV_10
		| 0x400601
		);
	mdelay(1);
	write32(mmiobase + DPLL(0),
		DPLL_VCO_ENABLE | DPLLB_MODE_DAC_SERIAL
		| DPLL_VGA_MODE_DIS
		| DPLL_DAC_SERIAL_P2_CLOCK_DIV_10
		| 0x400601
		);

	write32(mmiobase + ADPA, ADPA_DAC_ENABLE
			| ADPA_PIPE_A_SELECT
			| ADPA_USE_VGA_HVPOLARITY
			| ADPA_VSYNC_CNTL_ENABLE
			| ADPA_HSYNC_CNTL_ENABLE
			| ADPA_DPMS_ON
			);

	write32(mmiobase + HTOTAL(0),
		((hactive - 1) << 16)
		| (hactive - 1));
	write32(mmiobase + HBLANK(0),
		((hactive - 1) << 16)
		| (hactive - 1));
	write32(mmiobase + HSYNC(0),
		((hactive - 1) << 16)
		| (hactive - 1));

	write32(mmiobase + VTOTAL(0), ((vactive - 1) << 16)
		| (vactive - 1));
	write32(mmiobase + VBLANK(0), ((vactive - 1) << 16)
		| (vactive - 1));
	write32(mmiobase + VSYNC(0),
		((vactive - 1) << 16)
		| (vactive - 1));

	write32(mmiobase + PF_WIN_POS(0), 0);

	write32(mmiobase + PIPESRC(0), (639 << 16) | 399);
	write32(mmiobase + PF_CTL(0), PF_ENABLE | PF_FILTER_MED_3x3);
	write32(mmiobase + PF_WIN_SZ(0), vactive | (hactive << 16));
	write32(mmiobase + PFIT_CONTROL, 0x0);

	mdelay(1);

	write32(mmiobase + FDI_RX_CTL(0), 0x00002040);
	mdelay(1);
	write32(mmiobase + FDI_RX_CTL(0), 0x80002050);
	write32(mmiobase + FDI_TX_CTL(0), 0x00044000);
	mdelay(1);
	write32(mmiobase + FDI_TX_CTL(0), 0x80044000);
	write32(mmiobase + PIPECONF(0), PIPECONF_ENABLE | PIPECONF_BPP_6 | PIPECONF_DITHER_EN);

	write32(mmiobase + VGACNTRL, 0x0);
	write32(mmiobase + DSPCNTR(0), DISPLAY_PLANE_ENABLE | DISPPLANE_BGRX888);
	mdelay(1);

	write32(mmiobase + ADPA, ADPA_DAC_ENABLE
			| ADPA_PIPE_A_SELECT
			| ADPA_USE_VGA_HVPOLARITY
			| ADPA_VSYNC_CNTL_ENABLE
			| ADPA_HSYNC_CNTL_ENABLE
			| ADPA_DPMS_ON
			);

	write32(mmiobase + DSPFW3, 0x7f3f00c1);
	write32(mmiobase + MI_MODE, 0x200 | VS_TIMER_DISPATCH);
	write32(mmiobase + CACHE_MODE_0, (0x6820 | (1 << 9)) & ~(1 << 5));
	write32(mmiobase + CACHE_MODE_1, 0x380 & ~(1 << 9));

	/* Set up GTT.  */

	reg16 = pci_read_config16(pcidev_on_root(0, 0), GGC);
	uma_size = 0;
	if (!(reg16 & 2)) {
		uma_size = decode_igd_memory_size((reg16 >> 4) & 7);
		printk(BIOS_DEBUG, "%dM UMA\n", uma_size >> 10);
	}

	for (i = 0; i < (uma_size - 256) / 4; i++) {
		outl((i << 2) | 1, piobase);
		outl(pphysbase + (i << 12) + 1, piobase + 4);
	}

	/* Clear interrupts. */
	write32(mmiobase + DEIIR, 0xffffffff);
	write32(mmiobase + SDEIIR, 0xffffffff);
	write32(mmiobase + IIR, 0xffffffff);
	write32(mmiobase + IMR, 0xffffffff);
	write32(mmiobase + EIR, 0xffffffff);

	vga_textmode_init();

	/* Enable screen memory.  */
	vga_sr_write(1, vga_sr_read(1) & ~0x20);

	return 0;

}

/* compare the header of the vga edid header */
/* if vga is not connected it should have a correct header */
static int probe_edid(u8 *mmiobase, u8 slave)
{
	int i;
	u8 vga_edid[128];
	u8 header[8] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
	intel_gmbus_read_edid(mmiobase + GMBUS0, slave, 0x50, vga_edid, 128);
	intel_gmbus_stop(mmiobase + GMBUS0);
	for (i = 0; i < 8; i++) {
		if (vga_edid[i] != header[i]) {
			printk(BIOS_DEBUG, "No display connected on slave %d\n",
				slave);
			return 0;
		}
	}
	printk(BIOS_SPEW, "Found a display on slave %d\n", slave);
	return 1;
}

static u32 get_cdclk(struct device *const dev)
{
	u16 gcfgc = pci_read_config16(dev, GCFGC);

	if (gcfgc & GC_LOW_FREQUENCY_ENABLE)
		return 133333333;

	switch (gcfgc & GC_DISPLAY_CLOCK_MASK) {
	case GC_DISPLAY_CLOCK_333_320_MHZ:
		return 320000000;
	default:
	case GC_DISPLAY_CLOCK_190_200_MHZ:
		return 200000000;
	}
}

static u32 freq_to_blc_pwm_ctl(struct device *const dev, u16 pwm_freq)
{
	u32 blc_mod;

	/* Set duty cycle to 100% due to use of legacy backlight control */
	blc_mod = get_cdclk(dev) / (32 * pwm_freq);
	return BLM_LEGACY_MODE | ((blc_mod / 2) << 17) | ((blc_mod / 2) << 1);
}


static void panel_setup(u8 *mmiobase, struct device *const dev)
{
	const struct northbridge_intel_i945_config *const conf = dev->chip_info;

	u32 reg32;

	/* Set up Panel Power On Delays */
	reg32 = (conf->gpu_panel_power_up_delay & 0x1fff) << 16;
	reg32 |= (conf->gpu_panel_power_backlight_on_delay & 0x1fff);
	write32(mmiobase + PP_ON_DELAYS, reg32);

	/* Set up Panel Power Off Delays */
	reg32 = (conf->gpu_panel_power_down_delay & 0x1fff) << 16;
	reg32 |= (conf->gpu_panel_power_backlight_off_delay & 0x1fff);
	write32(mmiobase + PP_OFF_DELAYS, reg32);

	/* Set up Panel Power Cycle Delay */
	reg32 = (get_cdclk(dev) / 20000 - 1) << PP_REFERENCE_DIVIDER_SHIFT;
	reg32 |= conf->gpu_panel_power_cycle_delay & 0x1f;
	write32(mmiobase + PP_DIVISOR, reg32);

	/* Backlight init. */
	if (conf->pwm_freq)
		write32(mmiobase + BLC_PWM_CTL, freq_to_blc_pwm_ctl(dev,
							conf->pwm_freq));
	else
		write32(mmiobase + BLC_PWM_CTL, freq_to_blc_pwm_ctl(dev,
							DEFAULT_BLC_PWM));
}

static void gma_ngi(struct device *const dev)
{
	/* This should probably run before post VBIOS init. */
	printk(BIOS_INFO, "Initializing VGA without OPROM.\n");
	void *mmiobase;
	u32 iobase, graphics_base;
	struct northbridge_intel_i945_config *conf = dev->chip_info;

	iobase = dev->resource_list[1].base;
	mmiobase = (void *)(uintptr_t)dev->resource_list[0].base;
	graphics_base = dev->resource_list[2].base;

	printk(BIOS_SPEW, "GMADR = 0x%08x GTTADR = 0x%08x\n",
		pci_read_config32(dev, GMADR), pci_read_config32(dev, GTTADR));

	int err;

	if (CONFIG(NORTHBRIDGE_INTEL_SUBTYPE_I945GM))
		panel_setup(mmiobase, dev);

	/* probe if VGA is connected and always run */
	/* VGA init if no LVDS is connected */
	if (!probe_edid(mmiobase, GMBUS_PORT_PANEL) ||
			probe_edid(mmiobase, GMBUS_PORT_VGADDC))
		err = intel_gma_init_vga(conf,
				pci_read_config32(dev, 0x5c) & ~0xf,
				iobase, mmiobase, graphics_base);
	else
		err = intel_gma_init_lvds(conf,
				pci_read_config32(dev, 0x5c) & ~0xf,
				iobase, mmiobase, graphics_base);
	if (err == 0)
		gfx_set_init_done(1);
	/* Linux relies on VBT for panel info.  */
	if (CONFIG(NORTHBRIDGE_INTEL_SUBTYPE_I945GM)) {
		generate_fake_intel_oprom(&conf->gfx, dev, "$VBT CALISTOGA");
	}
	if (CONFIG(NORTHBRIDGE_INTEL_SUBTYPE_I945GC)) {
		generate_fake_intel_oprom(&conf->gfx, dev, "$VBT LAKEPORT-G");
	}
}

static void gma_func0_init(struct device *dev)
{
	u32 reg32;

	/* Unconditionally reset graphics */
	pci_write_config8(dev, GDRST, 1);
	udelay(50);
	pci_write_config8(dev, GDRST, 0);
	/* wait for device to finish */
	while (pci_read_config8(dev, GDRST) & 1)
		;

	/* IGD needs to be Bus Master */
	reg32 = pci_read_config32(dev, PCI_COMMAND);
	pci_write_config32(dev, PCI_COMMAND, reg32 | PCI_COMMAND_MASTER
		 | PCI_COMMAND_IO | PCI_COMMAND_MEMORY);

	if (CONFIG(MAINBOARD_DO_NATIVE_VGA_INIT)) {
		int vga_disable = (pci_read_config16(dev, GGC) & 2) >> 1;
		if (acpi_is_wakeup_s3()) {
			printk(BIOS_INFO,
				"Skipping native VGA initialization when resuming from ACPI S3.\n");
		} else {
			if (vga_disable) {
				printk(BIOS_INFO,
				       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
			} else {
				gma_ngi(dev);
			}
		}
	} else {
		/* PCI Init, will run VBIOS */
		pci_dev_init(dev);
	}

	intel_gma_restore_opregion();
}

/* This doesn't reclaim stolen UMA memory, but IGD could still
   be re-enabled later. */
static void gma_func0_disable(struct device *dev)
{
	struct device *dev_host = pcidev_on_root(0x0, 0);

	pci_write_config16(dev, GCFC, 0xa00);
	pci_write_config16(dev_host, GGC, (1 << 1));

	unsigned int reg32 = pci_read_config32(dev_host, DEVEN);
	reg32 &= ~(DEVEN_D2F0 | DEVEN_D2F1);
	pci_write_config32(dev_host, DEVEN, reg32);

	dev->enabled = 0;
}

static void gma_func1_init(struct device *dev)
{
	u32 reg32;
	u8 val;

	/* IGD needs to be Bus Master, also enable IO access */
	reg32 = pci_read_config32(dev, PCI_COMMAND);
	pci_write_config32(dev, PCI_COMMAND, reg32 |
			PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY | PCI_COMMAND_IO);

	if (get_option(&val, "tft_brightness") == CB_SUCCESS)
		pci_write_config8(dev, 0xf4, val);
	else
		pci_write_config8(dev, 0xf4, 0xff);
}

static void gma_generate_ssdt(struct device *device)
{
	const struct northbridge_intel_i945_config *chip = device->chip_info;

	drivers_intel_gma_displays_ssdt_generate(&chip->gfx);
}

static void gma_func0_read_resources(struct device *dev)
{
	u8 reg8;

	/* Set Untrusted Aperture Size to 256mb */
	reg8 = pci_read_config8(dev, MSAC);
	reg8 &= ~0x3;
	reg8 |= 0x2;
	pci_write_config8(dev, MSAC, reg8);

	pci_dev_read_resources(dev);
}

static unsigned long
gma_write_acpi_tables(const struct device *const dev,
		      unsigned long current,
		      struct acpi_rsdp *const rsdp)
{
	igd_opregion_t *opregion = (igd_opregion_t *)current;
	global_nvs_t *gnvs;

	if (intel_gma_init_igd_opregion(opregion) != CB_SUCCESS)
		return current;

	current += sizeof(igd_opregion_t);

	/* GNVS has been already set up */
	gnvs = cbmem_find(CBMEM_ID_ACPI_GNVS);
	if (gnvs) {
		/* IGD OpRegion Base Address */
		gma_set_gnvs_aslb(gnvs, (uintptr_t)opregion);
	} else {
		printk(BIOS_ERR, "Error: GNVS table not found.\n");
	}

	current = acpi_align_current(current);
	return current;
}

static const char *gma_acpi_name(const struct device *dev)
{
	return "GFX0";
}

static struct pci_operations gma_pci_ops = {
	.set_subsystem    = pci_dev_set_subsystem,
};

static struct device_operations gma_func0_ops = {
	.read_resources		= gma_func0_read_resources,
	.set_resources		= pci_dev_set_resources,
	.enable_resources	= pci_dev_enable_resources,
	.init			= gma_func0_init,
	.acpi_fill_ssdt		= gma_generate_ssdt,
	.disable		= gma_func0_disable,
	.ops_pci		= &gma_pci_ops,
	.acpi_name		= gma_acpi_name,
	.write_acpi_tables	= gma_write_acpi_tables,
};


static struct device_operations gma_func1_ops = {
	.read_resources		= pci_dev_read_resources,
	.set_resources		= pci_dev_set_resources,
	.enable_resources	= pci_dev_enable_resources,
	.init			= gma_func1_init,
	.ops_pci		= &gma_pci_ops,
};

static const unsigned short i945_gma_func0_ids[] = {
	0x2772, /* 82945G/GZ Integrated Graphics Controller */
	0x27a2, /* Mobile 945GM/GMS Express Integrated Graphics Controller*/
	0x27ae, /* Mobile 945GSE Express Integrated Graphics Controller */
	0
};

static const unsigned short i945_gma_func1_ids[] = {
	0x2776, /* Desktop 82945G/GZ/GC */
	0x27a6, /* Mobile 945GM/GMS/GME Express Integrated Graphics Controller */
	0
};

static const struct pci_driver i945_gma_func0_driver __pci_driver = {
	.ops		= &gma_func0_ops,
	.vendor		= PCI_VENDOR_ID_INTEL,
	.devices	= i945_gma_func0_ids,
};

static const struct pci_driver i945_gma_func1_driver __pci_driver = {
	.ops		= &gma_func1_ops,
	.vendor		= PCI_VENDOR_ID_INTEL,
	.devices	= i945_gma_func1_ids,
};