lib/fmap: Disable pre-RAM cache for FSP 1.0

Due to the way CAR teardown is handled in FSP 1.0, the results of
car_get_var_ptr() aren't always reliable, which can break things when
running with FMAP cache. It might be possible to fix this but would make
the code rather complicated, so let's just disable the feature on these
platforms and hope they die out soon.

Also allow this option to be used by platforms that don't have space for
the cache and want to save a little more code.

Change-Id: I7ffb1b8b08a7ca3fe8d53dc827e2c8521da064c7
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36937
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

5 files changed, 19 insertions, 4 deletions

diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index 972cb5234be9..36802509937d 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -58,7 +58,10 @@
 #endif
 
 	TIMESTAMP(., 0x200)
+
+#if !CONFIG(NO_FMAP_CACHE)
 	FMAP_CACHE(., FMAP_SIZE)
+#endif
 
 	_car_ehci_dbg_info = .;
 	/* Reserve sizeof(struct ehci_dbg_info). */
diff --git a/src/drivers/intel/fsp1_0/Kconfig b/src/drivers/intel/fsp1_0/Kconfig
index 32a07771eeff..1a1d4f707277 100644
--- a/src/drivers/intel/fsp1_0/Kconfig
+++ b/src/drivers/intel/fsp1_0/Kconfig
@@ -15,6 +15,7 @@ config PLATFORM_USES_FSP1_0
 	bool
 	default n
 	select CAR_GLOBAL_MIGRATION
+	select NO_FMAP_CACHE	# doesn't work with CAR_GLOBAL restrictions
 	help
 	  Selected for Intel processors/platform combinations that use the
 	  Intel Firmware Support Package (FSP) 1.0 for initialization.
diff --git a/src/lib/Kconfig b/src/lib/Kconfig
index cb1e4a5cc8f3..dd9974a8174c 100644
--- a/src/lib/Kconfig
+++ b/src/lib/Kconfig
@@ -68,3 +68,10 @@ config HWBASE_DIRECT_PCIDEV
 	def_bool y
 
 endif
+
+config NO_FMAP_CACHE
+	bool
+	help
+	  If your platform really doesn't want to use an FMAP cache (e.g. due to
+	  space constraints), you can select this to disable warnings and save
+	  a bit more code.
diff --git a/src/lib/fmap.c b/src/lib/fmap.c
index 4b4179c7698d..48aab8f3d5d0 100644
--- a/src/lib/fmap.c
+++ b/src/lib/fmap.c
@@ -60,6 +60,9 @@ static void report(const struct fmap *fmap)
 
 static void setup_preram_cache(struct mem_region_device *cache_mrdev)
 {
+	if (CONFIG(NO_FMAP_CACHE))
+		return;
+
 	if (!ENV_ROMSTAGE_OR_BEFORE) {
 		/* We get here if ramstage makes an FMAP access before calling
 		   cbmem_initialize(). We should avoid letting it come to that,
@@ -70,10 +73,10 @@ static void setup_preram_cache(struct mem_region_device *cache_mrdev)
 	}
 
 	if (REGION_SIZE(fmap_cache) == 0) {
-		/* If you see this you really want to add an FMAP_CACHE to your
-		   memlayout, unless you absolutely can't affort the 2K. */
-		print_once(BIOS_NOTICE,
-			"NOTE: Running without FMAP_CACHE, should add it!\n");
+		/* If you see this you should add FMAP_CACHE() to your memlayout
+		   (or select NO_FMAP_CACHE if you can't afford the 2K). */
+		print_once(BIOS_ERR,
+			"ERROR: FMAP_CACHE enabled but no region provided!\n");
 		return;
 	}
 
diff --git a/src/soc/rockchip/rk3288/Kconfig b/src/soc/rockchip/rk3288/Kconfig
index 3aebab975430..6a44ccd2e01b 100644
--- a/src/soc/rockchip/rk3288/Kconfig
+++ b/src/soc/rockchip/rk3288/Kconfig
@@ -29,6 +29,7 @@ config SOC_ROCKCHIP_RK3288
 	select MAINBOARD_FORCE_NATIVE_VGA_INIT
 	select HAVE_LINEAR_FRAMEBUFFER
 	select NO_BOOTBLOCK_CONSOLE
+	select NO_FMAP_CACHE
 
 if SOC_ROCKCHIP_RK3288