lib/device_tree: Add some FDT helper functions

This adds some helper functions for FDT, since more and more mainboards
seem to need FDT nowadays. For example our QEMU boards need it in order
to know how much RAM is available. Also all RISC-V boards in our tree
need FDT.

This also adds some tests in order to test said functions.

Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Change-Id: I2fb1d93c5b3e1cb2f7d9584db52bbce3767b63d8
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81081
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 138 insertions, 0 deletions

diff --git a/tests/data/lib/devicetree-test/tegra30-ouya.dtb b/tests/data/lib/devicetree-test/tegra30-ouya.dtb
new file mode 100644
index 0000000000..ae8ee6ac4a
--- /dev/null
+++ b/tests/data/lib/devicetree-test/tegra30-ouya.dtb
diff --git a/tests/lib/Makefile.mk b/tests/lib/Makefile.mk
index 7fc5471529..2090ef8831 100644
--- a/tests/lib/Makefile.mk
+++ b/tests/lib/Makefile.mk
@@ -39,9 +39,15 @@ tests-y += cbfs-lookup-no-mcache-test
 tests-y += cbfs-lookup-has-mcache-test
 tests-y += lzma-test
 tests-y += ux_locales-test
+tests-y += device_tree-test
 
 lib-test-srcs += tests/lib/lib-test.c
 
+device_tree-test-srcs += tests/lib/device_tree-test.c
+device_tree-test-srcs += tests/stubs/console.c
+device_tree-test-srcs += src/lib/device_tree.c
+device_tree-test-syssrcs += tests/helpers/file.c
+
 string-test-srcs += tests/lib/string-test.c
 string-test-srcs += src/lib/string.c
 
diff --git a/tests/lib/device_tree-test.c b/tests/lib/device_tree-test.c
new file mode 100644
index 0000000000..21f81c6beb
--- /dev/null
+++ b/tests/lib/device_tree-test.c
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/console.h>
+#include <device_tree.h>
+#include <helpers/file.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <tests/test.h>
+
+static int setup_device_tree_test_group(void **state)
+{
+	/*
+	 * fattest FDT I could find from Linux Kernel to test the worst cases
+	 * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/nvidia/tegra30-ouya.dts?id=443b349019f2d946
+	 */
+	const char dtb_path[] = "lib/devicetree-test/tegra30-ouya.dtb";
+	int file_size = test_get_file_size(dtb_path);
+	assert_int_not_equal(file_size, -1);
+
+	void *big_fat_dtb = test_malloc(file_size);
+	assert_int_not_equal(big_fat_dtb, NULL);
+	assert_int_equal(test_read_file(dtb_path, big_fat_dtb, file_size), file_size);
+	*state = big_fat_dtb;
+
+	return 0;
+}
+
+static int teardown_device_tree_test_group(void **state)
+{
+	test_free(*state);
+	return 0;
+}
+
+static void test_fdt_find_node_by_path(void **state)
+{
+	uint32_t addrcp, sizecp;
+	assert_int_equal(0, fdt_find_node_by_path(*state, "test", &addrcp, &sizecp));
+	assert_int_equal(56, fdt_find_node_by_path(*state, "/", &addrcp, &sizecp));
+	assert_int_equal(2, addrcp);
+	assert_int_equal(1, sizecp);
+	assert_int_equal(0, fdt_find_node_by_path(*state, "/test", &addrcp, &sizecp));
+	assert_int_equal(0x181f4, fdt_find_node_by_path(*state, "/chosen", &addrcp, &sizecp));
+	assert_int_equal(1, addrcp);
+	assert_int_equal(1, sizecp);
+	assert_int_equal(0x156d4, fdt_find_node_by_path(*state, "/cpus", &addrcp, &sizecp));
+	assert_int_equal(1, addrcp);
+	assert_int_equal(1, sizecp);
+	assert_int_equal(0x1517c, fdt_find_node_by_path(*state, "/usb@7d004000/ethernet@2", &addrcp, &sizecp));
+	assert_int_equal(1, addrcp);
+	assert_int_equal(0, sizecp);
+	assert_int_equal(0x1517c, fdt_find_node_by_path(*state, "/usb@7d004000/ethernet@2/", &addrcp, &sizecp));
+	assert_int_equal(1, addrcp);
+	assert_int_equal(0, sizecp);
+
+	assert_int_equal(0xee08, fdt_find_node_by_path(*state, "/pinmux@70000868/pinmux/drive_groups",
+						       &addrcp, &sizecp));
+}
+
+static void test_fdt_find_subnodes_by_prefix(void **state)
+{
+	uint32_t offset = fdt_find_node_by_path(*state, "/cpus", NULL, NULL);
+	uint32_t results[3] = { 0 };
+	uint32_t addrcp, sizecp;
+	size_t count_results = fdt_find_subnodes_by_prefix(*state, offset, "cpu@",
+							   &addrcp, &sizecp, results, 3);
+	assert_int_equal(3, count_results);
+	assert_int_equal(0x15700, results[0]);
+	assert_int_equal(0x157a0, results[1]);
+	assert_int_equal(0x15840, results[2]);
+
+	results[1] = 0xDEADBEEF;
+	results[2] = 0xDEADBEEF;
+	count_results = fdt_find_subnodes_by_prefix(*state, offset, "cpu@",
+							   &addrcp, &sizecp, results, 1);
+	assert_int_equal(1, count_results);
+	assert_int_equal(0x15700, results[0]);
+	assert_int_equal(0xDEADBEEF, results[1]);
+	assert_int_equal(0xDEADBEEF, results[2]);
+}
+
+static void test_fdt_find_node_by_alias(void **state)
+{
+	assert_int_equal(0xf298, fdt_find_node_by_alias(*state, "serial0", NULL, NULL));
+	assert_int_equal(0, fdt_find_node_by_alias(*state, "mmc2", NULL, NULL));
+}
+
+static void test_fdt_find_prop_in_node(void **state)
+{
+	uintptr_t cnode_offset = fdt_find_node_by_path(*state, "/clock", NULL, NULL);
+	uintptr_t mnode_offset = fdt_find_node_by_path(*state, "/memory@80000000", NULL, NULL);
+	assert_int_equal(0x18400, cnode_offset);
+
+	struct fdt_property fdt_prop;
+	assert_int_equal(0x1840c, fdt_read_prop(*state, cnode_offset, "compatible", &fdt_prop));
+	assert_string_equal("fixed-clock", (char *)fdt_prop.data);
+	assert_int_equal(0x6094, fdt_read_prop(*state, mnode_offset, "reg", &fdt_prop));
+	assert_int_equal(0x0, fdt_read_prop(*state, cnode_offset, "notfound", &fdt_prop));
+}
+
+static void test_fdt_read_reg_prop(void **state)
+{
+	uint32_t addrcp1, sizecp1, addrcp2, sizecp2;
+	uint64_t node_offset1 = fdt_find_node_by_path(*state, "/memory@80000000", &addrcp1, &sizecp1);
+	uint64_t node_offset2 = fdt_find_node_by_path(*state, "/reserved-memory/ramoops@bfdf0000", &addrcp2, &sizecp2);
+
+	struct device_tree_region regions[3];
+	regions[0].addr = 0xDEADBEEF;
+	regions[0].size = 0xDEADBEEF;
+	fdt_read_reg_prop(*state, node_offset1, addrcp1, sizecp1, regions, 0);
+	assert_int_equal(0xDEADBEEF, regions[0].addr);
+	assert_int_equal(0xDEADBEEF, regions[0].size);
+	fdt_read_reg_prop(*state, node_offset2, addrcp2, sizecp2, regions, 1);
+	assert_int_equal(0xbfdf0000, regions[0].addr);
+	assert_int_equal(0x00010000, regions[0].size);
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_fdt_find_node_by_path),
+		cmocka_unit_test(test_fdt_find_subnodes_by_prefix),
+		cmocka_unit_test(test_fdt_find_node_by_alias),
+		cmocka_unit_test(test_fdt_find_prop_in_node),
+		cmocka_unit_test(test_fdt_read_reg_prop),
+	};
+
+	return cb_run_group_tests(tests, setup_device_tree_test_group,
+			teardown_device_tree_test_group);
+}