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>
This commit is contained in:
Yu-Ping Wu 2021-06-22 17:40:01 +08:00 committed by Patrick Georgi
parent 6cd4d32039
commit fc3576ab06
4 changed files with 83 additions and 0 deletions

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@ -88,4 +88,39 @@
/* Calculate size of structure member. */
#define member_size(type, member) (sizeof(((type *)0)->member))
#define _retry_impl(attempts, condition, expr, ...) \
({ \
__typeof__(condition) _retry_ret = \
(__typeof__(condition))0; \
int _retry_attempts = (attempts); \
do { \
_retry_ret = (condition); \
if (_retry_ret) \
break; \
if (--_retry_attempts > 0) { \
expr; \
} else { \
break; \
} \
} while (1); \
_retry_ret; \
})
/*
* Helper macro to retry until a condition becomes true or the maximum number
* of attempts is reached. Two forms are supported:
*
* 1. retry(attempts, condition)
* 2. retry(attempts, condition, expr)
*
* @param attempts Maximum attempts.
* @param condition Condition to retry for.
* @param expr Procedure to run between each evaluation to "condition".
*
* @return Condition value if it evaluates to true within the maximum attempts;
* 0 otherwise.
*/
#define retry(attempts, condition, ...) \
_retry_impl(attempts, condition, __VA_ARGS__)
#endif /* COMMONLIB_BSD_HELPERS_H */

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@ -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

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@ -0,0 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
tests-y += helpers-test
helpers-test-srcs += tests/commonlib/bsd/helpers-test.c

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@ -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);
}