helpers: Introduce retry macro

Introduce a macro retry(attempts, condition, expr) for retrying a
condition, which is extensively used in coreboot.

Example usage:

 if (!retry(3, read32(REG) == 0, mdelay(1))
         printk(BIOS_ERR, "Error waiting for REG to be 0\n");

BUG=none
TEST=make tests/commonlib/bsd/helpers-test
TEST=emerge-cherry coreboot
BRANCH=none

Change-Id: I421e4dcab949616bd68b3a14231da744b9f74eeb
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55778
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

3 files changed, 48 insertions, 0 deletions

diff --git a/tests/commonlib/Makefile.inc b/tests/commonlib/Makefile.inc
index c620754e33c7..054e7db16de3 100644
--- a/tests/commonlib/Makefile.inc
+++ b/tests/commonlib/Makefile.inc
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+subdirs-y += bsd
+
 tests-y += region-test
 
 region-test-srcs += tests/commonlib/region-test.c
diff --git a/tests/commonlib/bsd/Makefile.inc b/tests/commonlib/bsd/Makefile.inc
new file mode 100644
index 000000000000..56664d037cc2
--- /dev/null
+++ b/tests/commonlib/bsd/Makefile.inc
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+tests-y += helpers-test
+
+helpers-test-srcs += tests/commonlib/bsd/helpers-test.c
diff --git a/tests/commonlib/bsd/helpers-test.c b/tests/commonlib/bsd/helpers-test.c
new file mode 100644
index 000000000000..ec3f98bed17a
--- /dev/null
+++ b/tests/commonlib/bsd/helpers-test.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <commonlib/bsd/helpers.h>
+#include <tests/test.h>
+
+static void func(void)
+{
+	function_called();
+}
+
+static void test_retry(void **state)
+{
+	int count;
+
+	/* 2-argument form */
+	count = 0;
+	assert_true(retry(3, ++count == 1));
+	count = 0;
+	assert_true(retry(3, ++count == 3));
+	count = 0;
+	assert_false(retry(3, ++count == 4));
+
+	/* 3-argument form */
+	expect_function_calls(func, 9);
+	assert_null(retry(10, NULL, func()));
+
+	assert_int_equal(retry(10, 999, func()), 999);
+
+	count = 0;
+	expect_function_calls(func, 3);
+	assert_true(retry(10, ++count == 4, func()));
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_retry),
+	};
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}