mb/lenovo/t400: Implement hybrid graphic in romstage

The hybrid driver select by DRIVERS_LENOVO_HYBRID_GRAPHICS doesn't work
for t400/t500.
Replace it with a custom romstage implementation.

Tested on Lenovo T500 with dual graphics:
* Intel Native GFX init
* AMD VBios
* GNU Linux 4.8.13
* SeaBios as payload
* Discrete is working (44 W)
* Integrated is working (24 W)
* Switchable is working (34 W)
** Both GPUs are enabled, with Intel being connected to the panel
** DRI_PRIME allows to use AMD GPU
** ACPI doesn't seem to work (no vgaswitcheroo)

Depends on Change-Id: I4dc00005270240c048272b2e4f52ae46ba1c9422
Depends on Change-Id: If389016f3bb0c4c2fd0b826914997a87a9137201

Change-Id: I7496876e9b434d4a2388e1ede27ac604670339b7
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/18010
Tested-by: build bot (Jenkins)
Reviewed-by: Alexander Couzens <lynxis@fe80.eu>

src/mainboard/lenovo/t400/Kconfig

@@ -21,7 +21,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select MAINBOARD_HAS_NATIVE_VGA_INIT_TEXTMODECFG
 	select INTEL_INT15
 	select SUPERIO_NSC_PC87382
-	select DRIVERS_LENOVO_HYBRID_GRAPHICS
 
 config MAINBOARD_DIR
 	string

src/mainboard/lenovo/t400/Makefile.inc

@@ -15,3 +15,4 @@
 
 ramstage-y += dock.c
 ramstage-y += cstates.c
+romstage-y += hybrid_graphics.c

src/mainboard/lenovo/t400/cmos.layout

@@ -142,6 +142,7 @@ enumerations
 11    12     352M
 12    0     Integrated Only
 12    1     Discrete Only
+12    2     Switchable
 
 # -----------------------------------------------------------------
 checksums

src/mainboard/lenovo/t400/hybrid_graphics.c

@@ -0,0 +1,91 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2012 secunet Security Networks AG
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <stdint.h>
+#include <string.h>
+#include <southbridge/intel/common/gpio.h>
+#include <northbridge/intel/gm45/gm45.h>
+#include <console/console.h>
+#include <option.h>
+
+#define HYBRID_GRAPHICS_INTEGRATED_ONLY 0
+#define HYBRID_GRAPHICS_DISCRETE_ONLY 1
+#define HYBRID_GRAPHICS_SWITCHABLE 2
+
+#define MUX_GPIO 22
+#define BCL_CTL_GPIO 19
+#define GFX_PWR_EN_GPIO 49
+
+#define HYBRID_DETECT_GPIO 21
+
+void hybrid_graphics_init(sysinfo_t *sysinfo);
+
+static bool hybrid_graphics_installed(void)
+{
+	if (get_gpio(HYBRID_DETECT_GPIO))
+		return false;
+	else
+		return true;
+}
+
+void hybrid_graphics_init(sysinfo_t *sysinfo)
+{
+	/* Set default mode */
+	uint8_t hybrid_graphics_mode =
+	    HYBRID_GRAPHICS_INTEGRATED_ONLY;
+
+	if (!hybrid_graphics_installed()) {
+		printk(BIOS_DEBUG, "Hybrid graphics not installed.\n");
+		/* The display is not connected to a mux or switchable. */
+		sysinfo->enable_igd = 1;
+		sysinfo->enable_peg = 0;
+		return;
+	}
+
+	printk(BIOS_DEBUG, "Hybrid graphics available: ");
+	get_option(&hybrid_graphics_mode, "hybrid_graphics_mode");
+
+	/* Select appropriate hybrid graphics device */
+	switch (hybrid_graphics_mode) {
+	default:
+	case HYBRID_GRAPHICS_INTEGRATED_ONLY:
+		printk(BIOS_DEBUG, "Activating Integrated Only.\n");
+		set_gpio(MUX_GPIO, GPIO_LEVEL_LOW);
+		set_gpio(BCL_CTL_GPIO, GPIO_LEVEL_LOW);
+		set_gpio(GFX_PWR_EN_GPIO, GPIO_LEVEL_LOW);
+
+		sysinfo->enable_igd = 1;
+		sysinfo->enable_peg = 0;
+		break;
+	case HYBRID_GRAPHICS_DISCRETE_ONLY:
+		printk(BIOS_DEBUG, "Activating Discrete Only.\n");
+		set_gpio(MUX_GPIO, GPIO_LEVEL_HIGH);
+		set_gpio(BCL_CTL_GPIO, GPIO_LEVEL_HIGH);
+		set_gpio(GFX_PWR_EN_GPIO, GPIO_LEVEL_HIGH);
+
+		sysinfo->enable_igd = 0;
+		sysinfo->enable_peg = 1;
+		break;
+	case HYBRID_GRAPHICS_SWITCHABLE:
+		printk(BIOS_DEBUG, "Activating Switchable (both GPUs).\n");
+		set_gpio(MUX_GPIO, GPIO_LEVEL_LOW);
+		set_gpio(BCL_CTL_GPIO, GPIO_LEVEL_LOW);
+		set_gpio(GFX_PWR_EN_GPIO, GPIO_LEVEL_HIGH);
+
+		sysinfo->enable_igd = 1;
+		sysinfo->enable_peg = 1;
+		break;
+	}
+}

src/mainboard/lenovo/t400/romstage.c

@@ -36,6 +36,8 @@
 #define LPC_DEV PCI_DEV(0, 0x1f, 0)
 #define MCH_DEV PCI_DEV(0, 0, 0)
 
+void hybrid_graphics_init(sysinfo_t *sysinfo);
+
 static void early_lpc_setup(void)
 {
 	/* Set up SuperIO LPC forwards */
@@ -101,9 +103,13 @@ void mainboard_romstage_entry(unsigned long bist)
 	memset(&sysinfo, 0, sizeof(sysinfo));
 	sysinfo.spd_map[0] = 0x50;
 	sysinfo.spd_map[2] = 0x51;
-	sysinfo.enable_igd = 1;
-	sysinfo.enable_peg = 0;
 	get_gmch_info(&sysinfo);
+
+	/* Configure graphic GPIOs.
+	* Make sure there's a little delay between
+	* setup_pch_gpios() and this call ! */
+	hybrid_graphics_init(&sysinfo);
+
 	raminit(&sysinfo, s3resume);
 
 	const u32 deven = pci_read_config32(MCH_DEV, D0F0_DEVEN);