// SPDX-License-Identifier: GPL-2.0// Copyright (C) 2025 Arm Ltd./* This file is intended to be included into mpam_resctrl.c */ #include <kunit/test.h>#include <linux/array_size.h>#include <linux/bits.h>#include <linux/math.h>#include <linux/sprintf.h> struct percent_value_case {	u8	pc;	u8	width;	u16	value;}; /* * Mysterious inscriptions taken from the union of ARM DDI 0598D.b, * "Arm Architecture Reference Manual Supplement - Memory System * Resource Partitioning and Monitoring (MPAM), for A-profile * architecture", Section 9.8, "About the fixed-point fractional * format" (exact percentage entries only) and ARM IHI0099B.a * "MPAM system component specification", Section 9.3, * "The fixed-point fractional format": */static const struct percent_value_case percent_value_cases[] = {	/* Architectural cases: */	{   1,  8,    1 },	{   1, 12,  0x27 },	{   1, 16,  0x28e },	{  25,  8, 0x3f },	{  25, 12, 0x3ff },	{  25, 16, 0x3fff },	{  33,  8, 0x53 },	{  33, 12, 0x546 },	{  33, 16, 0x5479 },	{  35,  8, 0x58 },	{  35, 12, 0x598 },	{  35, 16, 0x5998 },	{  45,  8, 0x72 },	{  45, 12, 0x732 },	{  45, 16, 0x7332 },	{  50,  8, 0x7f },	{  50, 12, 0x7ff },	{  50, 16, 0x7fff },	{  52,  8, 0x84 },	{  52, 12, 0x850 },	{  52, 16, 0x851d },	{  55,  8, 0x8b },	{  55, 12, 0x8cb },	{  55, 16, 0x8ccb },	{  58,  8, 0x93 },	{  58, 12, 0x946 },	{  58, 16, 0x9479 },	{  75,  8, 0xbf },	{  75, 12, 0xbff },	{  75, 16, 0xbfff },	{  80,  8, 0xcb },	{  80, 12, 0xccb },	{  80, 16, 0xcccb },	{  88,  8, 0xe0 },	{  88, 12, 0xe13 },	{  88, 16, 0xe146 },	{  95,  8, 0xf2 },	{  95, 12, 0xf32 },	{  95, 16, 0xf332 },	{ 100,  8, 0xff },	{ 100, 12, 0xfff },	{ 100, 16, 0xffff },}; static void test_percent_value_desc(const struct percent_value_case *param,				    char *desc){	snprintf(desc, KUNIT_PARAM_DESC_SIZE,		 "pc=%d, width=%d, value=0x%.*x\n",		 param->pc, param->width,		 DIV_ROUND_UP(param->width, 4), param->value);} KUNIT_ARRAY_PARAM(test_percent_value, percent_value_cases,		  test_percent_value_desc); struct percent_value_test_info {	u32 pc;			/* result of value-to-percent conversion */	u32 value;		/* result of percent-to-value conversion */	u32 max_value;		/* maximum raw value allowed by test params */	unsigned int shift;	/* promotes raw testcase value to 16 bits */}; /* * Convert a reference percentage to a fixed-point MAX value and * vice-versa, based on param (not test->param_value!) */static void __prepare_percent_value_test(struct kunit *test,					 struct percent_value_test_info *res,					 const struct percent_value_case *param){	struct mpam_props fake_props = { }; 	/* Reject bogus test parameters that would break the tests: */	KUNIT_ASSERT_GE(test, param->width, 1);	KUNIT_ASSERT_LE(test, param->width, 16);	KUNIT_ASSERT_LT(test, param->value, 1 << param->width); 	mpam_set_feature(mpam_feat_mbw_max, &fake_props);	fake_props.bwa_wd = param->width; 	res->shift = 16 - param->width;	res->max_value = GENMASK_U32(param->width - 1, 0);	res->value = percent_to_mbw_max(param->pc, &fake_props);	res->pc = mbw_max_to_percent(param->value << res->shift, &fake_props);} static void test_get_mba_granularity(struct kunit *test){	int ret;	struct mpam_props fake_props = { }; 	/* Use MBW_MAX */	mpam_set_feature(mpam_feat_mbw_max, &fake_props); 	fake_props.bwa_wd = 0;	KUNIT_EXPECT_FALSE(test, mba_class_use_mbw_max(&fake_props)); 	fake_props.bwa_wd = 1;	KUNIT_EXPECT_TRUE(test, mba_class_use_mbw_max(&fake_props)); 	/* Architectural maximum: */	fake_props.bwa_wd = 16;	KUNIT_EXPECT_TRUE(test, mba_class_use_mbw_max(&fake_props)); 	/* No usable control... */	fake_props.bwa_wd = 0;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 0); 	fake_props.bwa_wd = 1;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 50);	/* DIV_ROUND_UP(100, 1 << 1)% = 50% */ 	fake_props.bwa_wd = 2;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 25);	/* DIV_ROUND_UP(100, 1 << 2)% = 25% */ 	fake_props.bwa_wd = 3;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 13);	/* DIV_ROUND_UP(100, 1 << 3)% = 13% */ 	fake_props.bwa_wd = 6;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 2);	/* DIV_ROUND_UP(100, 1 << 6)% = 2% */ 	fake_props.bwa_wd = 7;	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 1);	/* DIV_ROUND_UP(100, 1 << 7)% = 1% */ 	/* Granularity saturates at 1% */	fake_props.bwa_wd = 16; /* architectural maximum */	ret = get_mba_granularity(&fake_props);	KUNIT_EXPECT_EQ(test, ret, 1);	/* DIV_ROUND_UP(100, 1 << 16)% = 1% */} static void test_mbw_max_to_percent(struct kunit *test){	const struct percent_value_case *param = test->param_value;	struct percent_value_test_info res; 	/*	 * Since the reference values in percent_value_cases[] all	 * correspond to exact percentages, round-to-nearest will	 * always give the exact percentage back when the MPAM max	 * value has precision of 0.5% or finer.  (Always true for the	 * reference data, since they all specify 8 bits or more of	 * precision.	 *	 * So, keep it simple and demand an exact match:	 */	__prepare_percent_value_test(test, &res, param);	KUNIT_EXPECT_EQ(test, res.pc, param->pc);} static void test_percent_to_mbw_max(struct kunit *test){	const struct percent_value_case *param = test->param_value;	struct percent_value_test_info res; 	__prepare_percent_value_test(test, &res, param); 	KUNIT_EXPECT_GE(test, res.value, param->value << res.shift);	KUNIT_EXPECT_LE(test, res.value, (param->value + 1) << res.shift);	KUNIT_EXPECT_LE(test, res.value, res.max_value << res.shift); 	/* No flexibility allowed for 0% and 100%! */ 	if (param->pc == 0)		KUNIT_EXPECT_EQ(test, res.value, 0); 	if (param->pc == 100)		KUNIT_EXPECT_EQ(test, res.value, res.max_value << res.shift);} static const void *test_all_bwa_wd_gen_params(struct kunit *test, const void *prev,					      char *desc){	uintptr_t param = (uintptr_t)prev; 	if (param > 15)		return NULL; 	param++; 	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "wd=%u\n", (unsigned int)param); 	return (void *)param;} static unsigned int test_get_bwa_wd(struct kunit *test){	uintptr_t param = (uintptr_t)test->param_value; 	KUNIT_ASSERT_GE(test, param, 1);	KUNIT_ASSERT_LE(test, param, 16); 	return param;} static void test_mbw_max_to_percent_limits(struct kunit *test){	struct mpam_props fake_props = {0};	u32 max_value; 	mpam_set_feature(mpam_feat_mbw_max, &fake_props);	fake_props.bwa_wd = test_get_bwa_wd(test);	max_value = GENMASK(15, 16 - fake_props.bwa_wd); 	KUNIT_EXPECT_EQ(test, mbw_max_to_percent(max_value, &fake_props),			MAX_MBA_BW);	KUNIT_EXPECT_EQ(test, mbw_max_to_percent(0, &fake_props),			get_mba_min(&fake_props)); 	/*	 * Rounding policy dependent 0% sanity-check:	 * With round-to-nearest, the minimum mbw_max value really	 * should map to 0% if there are at least 200 steps.	 * (100 steps may be enough for some other rounding policies.)	 */	if (fake_props.bwa_wd >= 8)		KUNIT_EXPECT_EQ(test, mbw_max_to_percent(0, &fake_props), 0); 	if (fake_props.bwa_wd < 8 &&	    mbw_max_to_percent(0, &fake_props) == 0)		kunit_warn(test, "wd=%d: Testsuite/driver Rounding policy mismatch?",			   fake_props.bwa_wd);} /* * Check that converting a percentage to mbw_max and back again (or, as * appropriate, vice-versa) always restores the original value: */static void test_percent_max_roundtrip_stability(struct kunit *test){	struct mpam_props fake_props = {0};	unsigned int shift;	u32 pc, max, pc2, max2; 	mpam_set_feature(mpam_feat_mbw_max, &fake_props);	fake_props.bwa_wd = test_get_bwa_wd(test);	shift = 16 - fake_props.bwa_wd; 	/*	 * Converting a valid value from the coarser scale to the finer	 * scale and back again must yield the original value:	 */	if (fake_props.bwa_wd >= 7) {		/* More than 100 steps: only test exact pc values: */		for (pc = get_mba_min(&fake_props); pc <= MAX_MBA_BW; pc++) {			max = percent_to_mbw_max(pc, &fake_props);			pc2 = mbw_max_to_percent(max, &fake_props);			KUNIT_EXPECT_EQ(test, pc2, pc);		}	} else {		/* Fewer than 100 steps: only test exact mbw_max values: */		for (max = 0; max < 1 << 16; max += 1 << shift) {			pc = mbw_max_to_percent(max, &fake_props);			max2 = percent_to_mbw_max(pc, &fake_props);			KUNIT_EXPECT_EQ(test, max2, max);		}	}} static void test_percent_to_max_rounding(struct kunit *test){	const struct percent_value_case *param = test->param_value;	unsigned int num_rounded_up = 0, total = 0;	struct percent_value_test_info res; 	for (param = percent_value_cases, total = 0;	     param < &percent_value_cases[ARRAY_SIZE(percent_value_cases)];	     param++, total++) {		__prepare_percent_value_test(test, &res, param);		if (res.value > param->value << res.shift)			num_rounded_up++;	} 	/*	 * The MPAM driver applies a round-to-nearest policy, whereas a	 * round-down policy seems to have been applied in the	 * reference table from which the test vectors were selected.	 *	 * For a large and well-distributed suite of test vectors,	 * about half should be rounded up and half down compared with	 * the reference table.  The actual test vectors are few in	 * number and probably not very well distributed however, so	 * tolerate a round-up rate of between 1/4 and 3/4 before	 * crying foul:	 */ 	kunit_info(test, "Round-up rate: %u%% (%u/%u)\n",		   DIV_ROUND_CLOSEST(num_rounded_up * 100, total),		   num_rounded_up, total); 	KUNIT_EXPECT_GE(test, 4 * num_rounded_up, 1 * total);	KUNIT_EXPECT_LE(test, 4 * num_rounded_up, 3 * total);} static struct kunit_case mpam_resctrl_test_cases[] = {	KUNIT_CASE(test_get_mba_granularity),	KUNIT_CASE_PARAM(test_mbw_max_to_percent, test_percent_value_gen_params),	KUNIT_CASE_PARAM(test_percent_to_mbw_max, test_percent_value_gen_params),	KUNIT_CASE_PARAM(test_mbw_max_to_percent_limits, test_all_bwa_wd_gen_params),	KUNIT_CASE(test_percent_to_max_rounding),	KUNIT_CASE_PARAM(test_percent_max_roundtrip_stability,			 test_all_bwa_wd_gen_params),	{}}; static struct kunit_suite mpam_resctrl_test_suite = {	.name = "mpam_resctrl_test_suite",	.test_cases = mpam_resctrl_test_cases,}; kunit_test_suites(&mpam_resctrl_test_suite);