memblock tests: Add memblock reset function

Memblock simulator needs to be able to reset memblock data structures
between different test cases. Add a function that sets all fields to
their default values.

Add a test checking if memblock is being initialized to expected values.

Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Link: https://lore.kernel.org/r/8c185aa7e0dd68c2c7e937c9a06c90ae413e240f.1643796665.git.karolinadrobnik@gmail.com

tools/testing/memblock/tests/basic_api.c

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+#include <linux/memblock.h>
+#include "basic_api.h"
+
+#define EXPECTED_MEMBLOCK_REGIONS			128
+
+static int memblock_initialization_check(void)
+{
+	reset_memblock();
+
+	assert(memblock.memory.regions);
+	assert(memblock.memory.cnt == 1);
+	assert(memblock.memory.max == EXPECTED_MEMBLOCK_REGIONS);
+	assert(strcmp(memblock.memory.name, "memory") == 0);
+
+	assert(memblock.reserved.regions);
+	assert(memblock.reserved.cnt == 1);
+	assert(memblock.memory.max == EXPECTED_MEMBLOCK_REGIONS);
+	assert(strcmp(memblock.reserved.name, "reserved") == 0);
+
+	assert(!memblock.bottom_up);
+	assert(memblock.current_limit == MEMBLOCK_ALLOC_ANYWHERE);
+
+	return 0;
+}
+
+int memblock_basic_checks(void)
+{
+	memblock_initialization_check();
+	return 0;
+}