arm64: versal: Do not place u-boot to reserved memory location

Versal can also have reserved space in DT which u-boot has to avoid to
placing self to that location. The same change was done in ZynqMP by commit
ce39ee28ec31 ("zynqmp: Do not place u-boot to reserved memory location")
and also for microblaze by commit d7b5cc89d329 ("microblaze: Do not place
u-boot to reserved memory location").

The patch was tested by adding reserved-memory node to DT and check via
bdinfo back.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/15426fa6d64835dd23c5c8c12bbfc97306fb6098.1647527129.git.michal.simek@xilinx.com
diff --git a/board/xilinx/versal/board.c b/board/xilinx/versal/board.c
index 299e128..9940f2a 100644
--- a/board/xilinx/versal/board.c
+++ b/board/xilinx/versal/board.c
@@ -9,6 +9,7 @@
 #include <env.h>
 #include <fdtdec.h>
 #include <init.h>
+#include <image.h>
 #include <env_internal.h>
 #include <log.h>
 #include <malloc.h>
@@ -249,6 +250,25 @@
 	return 0;
 }
 
+ulong board_get_usable_ram_top(ulong total_size)
+{
+	phys_size_t size;
+	phys_addr_t reg;
+	struct lmb lmb;
+
+	/* found enough not-reserved memory to relocated U-Boot */
+	lmb_init(&lmb);
+	lmb_add(&lmb, gd->ram_base, gd->ram_size);
+	boot_fdt_add_mem_rsv_regions(&lmb, (void *)gd->fdt_blob);
+	size = ALIGN(CONFIG_SYS_MALLOC_LEN + total_size, MMU_SECTION_SIZE);
+	reg = lmb_alloc(&lmb, size, MMU_SECTION_SIZE);
+
+	if (!reg)
+		reg = gd->ram_top - size;
+
+	return reg + size;
+}
+
 void reset_cpu(void)
 {
 }