nb/intel/*/gma.c: Skip NGI when VGA decode is not enabled

Writes to VGA MEM and IO by NGI are invalid if the IGD is not decoding
them.

Change-Id: I4b9329d14105eb563a0d4aea6ef75ff11febf6df
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/27984
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

6 files changed, 81 insertions, 37 deletions

diff --git a/src/northbridge/intel/gm45/gma.c b/src/northbridge/intel/gm45/gma.c
index 606170ce73..5335fbb077 100644
--- a/src/northbridge/intel/gm45/gma.c
+++ b/src/northbridge/intel/gm45/gma.c
@@ -771,11 +771,18 @@ static void gma_func0_init(struct device *dev)
 	/* Post VBIOS init */
 	gma_pm_init_post_vbios(dev, edid_lvds.ascii_string);
 
-	if (IS_ENABLED(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT)) {
-		gma_ngi(dev, &edid_lvds);
-	} else if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
-		int lightup_ok;
-		gma_gfxinit(&lightup_ok);
+	int vga_disable = (pci_read_config16(dev, D0F0_GGC) & 2) >> 1;
+
+	if (vga_disable) {
+		printk(BIOS_INFO,
+		       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
+	} else {
+		if (IS_ENABLED(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT)) {
+			gma_ngi(dev, &edid_lvds);
+		} else if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
+			int lightup_ok;
+			gma_gfxinit(&lightup_ok);
+		}
 	}
 
 	intel_gma_restore_opregion();
diff --git a/src/northbridge/intel/haswell/gma.c b/src/northbridge/intel/haswell/gma.c
index 8ffdce84b2..8f60da4add 100644
--- a/src/northbridge/intel/haswell/gma.c
+++ b/src/northbridge/intel/haswell/gma.c
@@ -468,10 +468,17 @@ static void gma_func0_init(struct device *dev)
 	/* Pre panel init */
 	gma_setup_panel(dev);
 
+	int vga_disable = (pci_read_config16(dev, GGC) & 2) >> 1;
+
 	if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
-		printk(BIOS_SPEW, "NATIVE graphics, run native enable\n");
-		gma_gfxinit(&lightup_ok);
-		gfx_set_init_done(1);
+		if (vga_disable) {
+			printk(BIOS_INFO,
+			       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
+		} else {
+			printk(BIOS_SPEW, "NATIVE graphics, run native enable\n");
+			gma_gfxinit(&lightup_ok);
+			gfx_set_init_done(1);
+		}
 	}
 
 	if (! lightup_ok) {
diff --git a/src/northbridge/intel/i945/gma.c b/src/northbridge/intel/i945/gma.c
index 6c3d6ae5f3..83dc42ef99 100644
--- a/src/northbridge/intel/i945/gma.c
+++ b/src/northbridge/intel/i945/gma.c
@@ -700,12 +700,20 @@ static void gma_func0_init(struct device *dev)
 	pci_write_config32(dev, PCI_COMMAND, reg32 | PCI_COMMAND_MASTER
 		 | PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
 
+	int vga_disable = (pci_read_config16(dev, GGC) & 2) >> 1;
+
 	if (IS_ENABLED(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT)) {
-		if (acpi_is_wakeup_s3())
+		if (acpi_is_wakeup_s3()) {
 			printk(BIOS_INFO,
 				"Skipping native VGA initialization when resuming from ACPI S3.\n");
-		else
-			gma_ngi(dev);
+		} 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);
diff --git a/src/northbridge/intel/pineview/gma.c b/src/northbridge/intel/pineview/gma.c
index 8cf4d22554..02100e908d 100644
--- a/src/northbridge/intel/pineview/gma.c
+++ b/src/northbridge/intel/pineview/gma.c
@@ -275,6 +275,8 @@ static void gma_func0_init(struct device *dev)
 		struct resource *pio_res;
 		struct northbridge_intel_pineview_config *conf = dev->chip_info;
 
+		int vga_disable = (pci_read_config16(dev, GGC) & 2) >> 1;
+
 		/* Find base addresses */
 		mmio_res = find_resource(dev, 0x10);
 		gtt_res = find_resource(dev, 0x1c);
@@ -282,11 +284,17 @@ static void gma_func0_init(struct device *dev)
 		physbase = pci_read_config32(dev, 0x5c) & ~0xf;
 
 		if (gtt_res && gtt_res->base && physbase && pio_res && pio_res->base) {
-			printk(BIOS_SPEW, "Initializing VGA. MMIO 0x%llx\n",
-			       mmio_res->base);
-			intel_gma_init(conf, dev, res2mmio(mmio_res, 0, 0),
-				res2mmio(gtt_res, 0, 0),
-				physbase, pio_res->base);
+			if (vga_disable) {
+				printk(BIOS_INFO,
+				       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
+			} else {
+				printk(BIOS_SPEW, "Initializing VGA. MMIO 0x%llx\n",
+				       mmio_res->base);
+				intel_gma_init(conf, dev,
+					       res2mmio(mmio_res, 0, 0),
+					       res2mmio(gtt_res, 0, 0),
+					       physbase, pio_res->base);
+			}
 		}
 
 		/* Linux relies on VBT for panel info.  */
diff --git a/src/northbridge/intel/sandybridge/gma.c b/src/northbridge/intel/sandybridge/gma.c
index 73546ce985..042c2a9da5 100644
--- a/src/northbridge/intel/sandybridge/gma.c
+++ b/src/northbridge/intel/sandybridge/gma.c
@@ -631,29 +631,38 @@ static void gma_func0_init(struct device *dev)
 	/* Post VBIOS init */
 	gma_pm_init_post_vbios(dev);
 
+	int vga_disable = (pci_read_config16(dev, GGC) & 2) >> 1;
+
 	/* Running graphics init on S3 breaks Linux drm driver. */
 	if (!acpi_is_wakeup_s3() &&
 	    (IS_ENABLED(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT) ||
 	    IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT))) {
-		/* This should probably run before post VBIOS init. */
-		printk(BIOS_SPEW, "Initializing VGA without OPROM.\n");
-		u8 *mmiobase;
-		u32 iobase, physbase, graphics_base;
-		struct northbridge_intel_sandybridge_config *conf = dev->chip_info;
-		iobase = dev->resource_list[2].base;
-		mmiobase = res2mmio(&dev->resource_list[0], 0, 0);
-		physbase = pci_read_config32(dev, 0x5c) & ~0xf;
-		graphics_base = dev->resource_list[1].base;
-
-		int lightup_ok;
-		if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
-			gma_gfxinit(&lightup_ok);
+		if (vga_disable) {
+			printk(BIOS_INFO,
+			       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
 		} else {
-			lightup_ok = i915lightup_sandy(&conf->gfx, physbase,
-					iobase, mmiobase, graphics_base);
+			/* This should probably run before post VBIOS init. */
+			printk(BIOS_SPEW, "Initializing VGA without OPROM.\n");
+			u8 *mmiobase;
+			u32 iobase, physbase, graphics_base;
+			struct northbridge_intel_sandybridge_config *conf = dev->chip_info;
+			iobase = dev->resource_list[2].base;
+			mmiobase = res2mmio(&dev->resource_list[0], 0, 0);
+			physbase = pci_read_config32(dev, 0x5c) & ~0xf;
+			graphics_base = dev->resource_list[1].base;
+
+			int lightup_ok;
+			if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
+				gma_gfxinit(&lightup_ok);
+			} else {
+				lightup_ok = i915lightup_sandy(&conf->gfx,
+							       physbase,
+							       iobase, mmiobase,
+							       graphics_base);
+			}
+			if (lightup_ok)
+				gfx_set_init_done(1);
 		}
-		if (lightup_ok)
-			gfx_set_init_done(1);
 	}
 
 	gma_enable_swsci();
diff --git a/src/northbridge/intel/x4x/gma.c b/src/northbridge/intel/x4x/gma.c
index 2d2feee61c..d0c40b1d8d 100644
--- a/src/northbridge/intel/x4x/gma.c
+++ b/src/northbridge/intel/x4x/gma.c
@@ -60,7 +60,7 @@ void gma_set_gnvs_aslb(void *gnvs, uintptr_t aslb)
 
 static void gma_func0_init(struct device *dev)
 {
-	u16 reg16, ggc;
+	u16 reg16;
 	u32 reg32;
 
 	/* IGD needs to be Bus Master */
@@ -74,11 +74,16 @@ static void gma_func0_init(struct device *dev)
 	reg16 |= 0xbc;
 	pci_write_config16(dev_find_slot(0, PCI_DEVFN(0x2, 0)), 0xcc, reg16);
 
-	ggc = pci_read_config16(dev_find_slot(0, PCI_DEVFN(0, 0)), D0F0_GGC);
+	int vga_disable = pci_read_config16(dev, D0F0_GGC);
 
 	if (IS_ENABLED(CONFIG_MAINBOARD_USE_LIBGFXINIT)) {
-		int lightup_ok;
-		gma_gfxinit(&lightup_ok);
+		if (vga_disable) {
+			printk(BIOS_INFO,
+			       "IGD is not decoding legacy VGA MEM and IO: skipping NATIVE graphic init\n");
+		} else {
+			int lightup_ok;
+			gma_gfxinit(&lightup_ok);
+		}
 	} else {
 		pci_dev_init(dev);
 	}