lib/bootmem: Add method to walk memory tables

Add a method to walk bootmem memory tables and call a function
for each memory range. The tables might not match with OS sight
of view.
Return true if the callback function returned false.

Required for FIT support in coreboot to find a usable RAM region.

Tested on Cavium SoC.

Change-Id: I0004e5ad5fe2289827f370f0d0f9979d3cbd3926
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/25583
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/lib/bootmem.c

@@ -180,6 +180,20 @@ void bootmem_dump_ranges(void)
 	}
 }
 
+bool bootmem_walk(range_action_t action, void *arg)
+{
+	const struct range_entry *r;
+
+	assert(bootmem_is_initialized());
+
+	memranges_each_entry(r, &bootmem) {
+		if (!action(r, arg))
+			return true;
+	}
+
+	return false;
+}
+
 int bootmem_region_targets_usable_ram(uint64_t start, uint64_t size)
 {
 	const struct range_entry *r;