arm64: mvebu: Restrict memory size to a usable maximum

[u-boot] / arch / arm / mach-mvebu / arm64-common.c

diff --git a/arch/arm/mach-mvebu/arm64-common.c b/arch/arm/mach-mvebu/arm64-common.c
index 1fc2ff2f7cf3758a1a88b75ebaf374e7c812820a..8f026559c2f94d02dda4d531ddd7fcfc0668863b 100644 (file)
--- a/arch/arm/mach-mvebu/arm64-common.c
+++ b/arch/arm/mach-mvebu/arm64-common.c
@@ -16,6 +16,23 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+/*
+ * Not all memory is mapped in the MMU. So we need to restrict the
+ * memory size so that U-Boot does not try to access it. Also, the
+ * internal registers are located at 0xf000.0000 - 0xffff.ffff.
+ * Currently only 2GiB are mapped for system memory. This is what
+ * we pass to the U-Boot subsystem here.
+ */
+#define USABLE_RAM_SIZE                0x80000000
+
+ulong board_get_usable_ram_top(ulong total_size)
+{
+       if (gd->ram_size > USABLE_RAM_SIZE)
+               return USABLE_RAM_SIZE;
+
+       return gd->ram_size;
+}
+
 /*
  * On ARMv8, MBus is not configured in U-Boot. To enable compilation
  * of the already implemented drivers, lets add a dummy version of