soc/sifive/fu540: Support booting from SD card

Change-Id: I18948d31c0bf0bf9d641480a35fc710b9ee8ae84
Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35119
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/soc/sifive/fu540/include/soc/memlayout.ld b/src/soc/sifive/fu540/include/soc/memlayout.ld
index 1d11aa0..df30ede 100644
--- a/src/soc/sifive/fu540/include/soc/memlayout.ld
+++ b/src/soc/sifive/fu540/include/soc/memlayout.ld
@@ -28,10 +28,12 @@
 	CAR_STACK(FU540_L2LIM + 64K, 20K)
 	PRERAM_CBMEM_CONSOLE(FU540_L2LIM + 84K, 8K)
 	ROMSTAGE(FU540_L2LIM + 128K, 128K)
+	PRERAM_CBFS_CACHE(FU540_L2LIM + 256K, 128K)
 	L2LIM_END(FU540_L2LIM + 2M)
 
 	DRAM_START(FU540_DRAM)
 	REGION(opensbi, FU540_DRAM, 128K, 4K)
 	RAMSTAGE(FU540_DRAM + 128K, 256K)
 	MEM_STACK(FU540_DRAM + 448K, 20K)
+	POSTRAM_CBFS_CACHE(FU540_DRAM + 512K, 32M - 512K)
 }