soc/intel/common/gfx: rename and guard graphics_soc_init()

Rename to graphics_soc_panel_init, to more accurately convey
operations performed by the function. Guard execution so we
don't attempt to reconfigure the panel after FSP has already
done so.

This fixes FSP/GOP display init on APL/GLK, which was broken by
attempting to configure the panel after FSP had already done so.

Change-Id: I8e68a16b2efb59965077735578b1cc6ffd5a58f0
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48884
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/apollolake/graphics.c

@@ -51,7 +51,7 @@ static void graphics_configure_backlight(
 	}
 }
 
-void graphics_soc_init(struct device *const dev)
+void graphics_soc_panel_init(struct device *const dev)
 {
 	const struct soc_intel_apollolake_config *const conf = dev->chip_info;
 	const struct resource *mmio_res;

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

@@ -16,7 +16,7 @@
 #include <types.h>
 
 /* SoC Overrides */
-__weak void graphics_soc_init(struct device *dev)
+__weak void graphics_soc_panel_init(struct device *dev)
 {
 	/*
 	 * User needs to implement SoC override in case wishes
@@ -34,8 +34,12 @@ static void gma_init(struct device *const dev)
 {
 	intel_gma_init_igd_opregion();
 
-	/* SoC specific configuration. */
-	graphics_soc_init(dev);
+	/* SoC specific panel init/configuration.
+	   If FSP has already run/configured the IGD, we can assume the
+	   panel/backlight control have already been set up sufficiently
+	   and that we shouldn't attempt to reconfigure things. */
+	if (!CONFIG(RUN_FSP_GOP))
+		graphics_soc_panel_init(dev);
 
 	if (CONFIG(SOC_INTEL_CONFIGURE_DDI_A_4_LANES) && !acpi_is_wakeup_s3()) {
 		const u32 ddi_buf_ctl = graphics_gtt_read(DDI_BUF_CTL_A);

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

@@ -12,11 +12,11 @@
  */
 
 /*
- * Perform Graphics Initialization in ramstage
+ * Perform Graphics/Panel Initialization in ramstage
  * Input:
  * struct device *dev: device structure
  */
-void graphics_soc_init(struct device *dev);
+void graphics_soc_panel_init(struct device *dev);
 
 /* i915 controller info for ACPI backlight controls */
 const struct i915_gpu_controller_info *

src/soc/intel/skylake/graphics.c

@@ -12,7 +12,7 @@
 #include <soc/systemagent.h>
 #include <types.h>
 
-void graphics_soc_init(struct device *dev)
+void graphics_soc_panel_init(struct device *dev)
 {
 	struct soc_intel_skylake_config *conf = config_of(dev);
 	struct resource *mmio_res;