soc/intel/common/block: Add Intel VGA early graphics support

This patch introduces an early graphics driver which can be used in
romstage in cache-as-ram mode. The implementation relies on
`libgfxinit' and provide VGA text mode support.

SoCs wanting to take advantage of this driver must implement the
`early_graphics_soc_panel_init' function to set the panel power
sequence timing parameters.

BUG=b:252792591
BRANCH=firmware-brya-14505.B
TEST=Graphics bring up observed on skolas with extra patches

Change-Id: Ie4ad1215e5fadd0adc1271b6bd6ddb0ea258cb5b
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70299
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Maulik Vaghela <maulikvaghela@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/intel/gma/gma-gfx_init.ads

@@ -11,6 +11,9 @@ is
    procedure gfxinit (lightup_ok : out Interfaces.C.int);
    pragma Export (C, gfxinit, "gma_gfxinit");
 
+   procedure gfxstop (stop_ok : out Interfaces.C.int);
+   pragma Export (C, gfxstop, "gma_gfxstop");
+
    ----------------------------------------------------------------------------
 
    function c_fb_add_framebuffer_info

src/drivers/intel/gma/hires_fb/gma-gfx_init.adb

@@ -97,4 +97,17 @@ is
       end if;
    end gfxinit;
 
+   procedure gfxstop (stop_ok : out Interfaces.C.int)
+   is
+      success : boolean;
+   begin
+      HW.GFX.GMA.Initialize (Clean_State => True,
+      			     Success => success);
+      if success then
+         stop_ok := 1;
+      else
+         stop_ok := 0;
+      end if;
+   end gfxstop;
+
 end GMA.GFX_Init;

src/drivers/intel/gma/libgfxinit.h

@@ -17,6 +17,7 @@ enum {
 };
 
 void gma_gfxinit(int *lightup_ok);
+void gma_gfxstop(int *stop_ok);
 int gma_read_edid(unsigned char edid[], int port);
 
 #endif

src/drivers/intel/gma/text_fb/gma-gfx_init.adb

@@ -56,4 +56,17 @@ is
       end if;
    end gfxinit;
 
+   procedure gfxstop (stop_ok : out Interfaces.C.int)
+   is
+      success : boolean;
+   begin
+      HW.GFX.GMA.Initialize (Clean_State => True,
+      			     Success => success);
+      if success then
+         stop_ok := 1;
+      else
+         stop_ok := 0;
+      end if;
+   end gfxstop;
+
 end GMA.GFX_Init;

src/soc/intel/common/block/graphics/Kconfig

@@ -1,5 +1,6 @@
 config SOC_INTEL_COMMON_BLOCK_GRAPHICS
 	bool
+	select ROMSTAGE_VGA if MAINBOARD_USE_EARLY_LIBGFXINIT
 	help
 	  Intel Processor common Graphics support
 

src/soc/intel/common/block/graphics/Makefile.inc

@@ -1,2 +1,3 @@
 ## SPDX-License-Identifier: GPL-2.0-only
+romstage-$(CONFIG_SOC_INTEL_COMMON_BLOCK_GRAPHICS) += early_graphics.c
 ramstage-$(CONFIG_SOC_INTEL_COMMON_BLOCK_GRAPHICS) += graphics.c

src/soc/intel/common/block/graphics/early_graphics.c

@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <device/pci.h>
+#include <drivers/intel/gma/libgfxinit.h>
+#include <intelblocks/early_graphics.h>
+#include <soc/pci_devs.h>
+
+static bool initialized;
+
+static void device_init(void)
+{
+	/* Disable response in IO and MMIO space. */
+	pci_and_config16(SA_DEV_IGD, PCI_COMMAND,
+			~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY));
+
+	/* Program IGD Base Address Register 0. */
+	pci_write_config32(SA_DEV_IGD, PCI_BASE_ADDRESS_0,
+			   CONFIG_GFX_GMA_DEFAULT_MMIO);
+
+	/* Enable response in IO and MMIO space. */
+	pci_or_config16(SA_DEV_IGD, PCI_COMMAND,
+			(PCI_COMMAND_IO | PCI_COMMAND_MEMORY));
+}
+
+bool early_graphics_init(void)
+{
+	int ret;
+
+	if (!CONFIG(MAINBOARD_USE_EARLY_LIBGFXINIT))
+		return false;
+
+	/* Perform minimal graphic MMIO configuration. */
+	device_init();
+
+	/* Configure display panel. */
+	early_graphics_soc_panel_init();
+
+	gma_gfxinit(&ret);
+	initialized = !!ret;
+
+	return initialized;
+}
+
+void early_graphics_stop(void)
+{
+	int ret;
+
+	if (!initialized)
+		return;
+
+	gma_gfxstop(&ret);
+}

src/soc/intel/common/block/include/intelblocks/early_graphics.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef SOC_INTEL_COMMON_BLOCK_GRAPHICS_EARLY_H
+#define SOC_INTEL_COMMON_BLOCK_GRAPHICS_EARLY_H
+
+#include <stdbool.h>
+
+/*
+ * SoC override
+ *
+ * All new SoC must implement below functionality.
+ */
+
+/* Configure display panel */
+void early_graphics_soc_panel_init(void);
+
+/*
+ * Early graphics module API
+ * Graphics at this stage is limited to VGA text mode.
+ */
+
+/* Initialize graphics.  Return true if VGA text mode is ready to use. */
+bool early_graphics_init(void);
+
+/* Clear graphics configuration, turn off the displays. */
+void early_graphics_stop(void);
+
+#endif	/* SOC_INTEL_COMMON_BLOCK_GRAPHICS_EARLY_H */