arch/x86: Add X86_CUSTOM_BOOTMEDIA

In order to disable X86_TOP4G_BOOTMEDIA_MAP it requires the definition
to be overridden. This makes it a little less ergonomic to use. Instead
introduce the inverse option that can be selected. I chose to leave
X86_TOP4G_BOOTMEDIA_MAP since it keeps the Makefiles simple.

BUG=b:179699789
TEST=none

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I65bbc118bde88687a7d7749c87acf1cbdc56a269
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55853
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/arch/x86/Kconfig

@@ -137,11 +137,15 @@ config RAMTOP
 # Traditionally BIOS region on SPI flash boot media was memory mapped right below
 # 4G and it was the last region in the IFD. This way translation between CPU
 # address space to flash address was trivial. However some IFDs on newer SoCs
-# have BIOS region sandwiched between descriptor and other regions. Turning off
+# have BIOS region sandwiched between descriptor and other regions. Turning on
-# this option enables soc code to provide custom mmap_boot.c which can be used to
+# X86_CUSTOM_BOOTMEDIA disables X86_TOP4G_BOOTMEDIA_MAP which allows the
-# implement complex translation.
+# soc code to provide custom mmap_boot.c.
+config X86_CUSTOM_BOOTMEDIA
+	bool
+
 config X86_TOP4G_BOOTMEDIA_MAP
 	bool
+	depends on !X86_CUSTOM_BOOTMEDIA
 	default y
 
 # This is something you almost certainly don't want to mess with.

src/soc/intel/apollolake/Kconfig

@@ -112,6 +112,9 @@ config CPU_SPECIFIC_OPTIONS
 	select INTEL_GMA_ACPI
 	select INTEL_GMA_SWSMISCI
 	select HAVE_ASAN_IN_ROMSTAGE
+	# This SoC does not map SPI flash like many previous SoC. Therefore we
+	# provide a custom media driver that facilitates mapping
+	select X86_CUSTOM_BOOTMEDIA
 
 config MAX_CPUS
 	int
@@ -173,12 +176,6 @@ config C_ENV_BOOTBLOCK_SIZE
 	hex
 	default 0x8000
 
-# This SoC does not map SPI flash like many previous SoC. Therefore we provide
-# a custom media driver that facilitates mapping
-config X86_TOP4G_BOOTMEDIA_MAP
-	bool
-	default n
-
 config ROMSTAGE_ADDR
 	hex
 	default 0xfef20000

src/soc/intel/common/block/fast_spi/Kconfig

@@ -15,6 +15,10 @@ config FAST_SPI_DISABLE_WRITE_STATUS
 config FAST_SPI_SUPPORTS_EXT_BIOS_WINDOW
 	bool
 	depends on SOC_INTEL_COMMON_BLOCK_FAST_SPI
+	# Enable X86_CUSTOM_BOOTMEDIA because the fast SPI controller
+	# driver provides a custom boot media device when multiple decode
+	# windows are used for the BIOS region.
+	select X86_CUSTOM_BOOTMEDIA
 	help
 	  Fast SPI controller on the platform supports additional
 	  window for memory mapping BIOS region (region 1) on the SPI
@@ -45,14 +49,3 @@ config EXT_BIOS_WIN_SIZE
 	  Maximum size of the extended window reserved for mapping BIOS
 	  region greater than 16MiB. The actual mapped window might be
 	  smaller depending upon the size of the BIOS region.
-
-if FAST_SPI_SUPPORTS_EXT_BIOS_WINDOW
-
-# Disable X86_TOP4G_BOOTMEDIA_MAP because the fast SPI controller
-# driver provides a custom boot media device when multiple decode
-# windows are used for the BIOS region.
-
-config X86_TOP4G_BOOTMEDIA_MAP
-	default n
-
-endif