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author | Mark Brown <broonie@kernel.org> | 2020-06-01 14:01:44 +0200 |
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committer | Mark Brown <broonie@kernel.org> | 2020-06-01 14:01:44 +0200 |
commit | 5fb565b69dabd5a256fc116702331b54a4621dc9 (patch) | |
tree | 55c3cd9ba11101f9c2e3b6789d0b4d87f91e0732 /lib | |
parent | Merge remote-tracking branch 'regulator/for-5.7' into regulator-linus (diff) | |
parent | regulator: max8998: max8998_set_current_limit() can be static (diff) | |
download | linux-5fb565b69dabd5a256fc116702331b54a4621dc9.tar.xz linux-5fb565b69dabd5a256fc116702331b54a4621dc9.zip |
Merge remote-tracking branch 'regulator/for-5.8' into regulator-linus
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Kconfig | 3 | ||||
-rw-r--r-- | lib/Kconfig.debug | 12 | ||||
-rw-r--r-- | lib/Makefile | 2 | ||||
-rw-r--r-- | lib/linear_ranges.c | 245 | ||||
-rw-r--r-- | lib/test_linear_ranges.c | 228 |
5 files changed, 490 insertions, 0 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 5d53f9609c25..8ec05335426c 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -19,6 +19,9 @@ config RAID6_PQ_BENCHMARK Benchmark all available RAID6 PQ functions on init and choose the fastest one. +config LINEAR_RANGES + tristate + config PACKING bool "Generic bitfield packing and unpacking" default n diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 21d9c5f6e7ec..f3322a620674 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2092,6 +2092,18 @@ config LIST_KUNIT_TEST If unsure, say N. +config LINEAR_RANGES_TEST + tristate "KUnit test for linear_ranges" + depends on KUNIT + select LINEAR_RANGES + help + This builds the linear_ranges unit test, which runs on boot. + Tests the linear_ranges logic correctness. + For more information on KUnit and unit tests in general please refer + to the KUnit documentation in Documentation/dev-tools/kunit/. + + If unsure, say N. + config TEST_UDELAY tristate "udelay test driver" help diff --git a/lib/Makefile b/lib/Makefile index 685aee60de1d..cd548bfa8df9 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -125,6 +125,7 @@ obj-$(CONFIG_DEBUG_LIST) += list_debug.o obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o obj-$(CONFIG_BITREVERSE) += bitrev.o +obj-$(CONFIG_LINEAR_RANGES) += linear_ranges.o obj-$(CONFIG_PACKING) += packing.o obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o obj-$(CONFIG_CRC16) += crc16.o @@ -309,3 +310,4 @@ obj-$(CONFIG_OBJAGG) += objagg.o # KUnit tests obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o +obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o diff --git a/lib/linear_ranges.c b/lib/linear_ranges.c new file mode 100644 index 000000000000..9495ef3572b7 --- /dev/null +++ b/lib/linear_ranges.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * helpers to map values in a linear range to range index + * + * Original idea borrowed from regulator framework + * + * It might be useful if we could support also inversely proportional ranges? + * Copyright 2020 ROHM Semiconductors + */ + +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/linear_range.h> +#include <linux/module.h> + +/** + * linear_range_values_in_range - return the amount of values in a range + * @r: pointer to linear range where values are counted + * + * Compute the amount of values in range pointed by @r. Note, values can + * be all equal - range with selectors 0,...,2 with step 0 still contains + * 3 values even though they are all equal. + * + * Return: the amount of values in range pointed by @r + */ +unsigned int linear_range_values_in_range(const struct linear_range *r) +{ + if (!r) + return 0; + return r->max_sel - r->min_sel + 1; +} +EXPORT_SYMBOL_GPL(linear_range_values_in_range); + +/** + * linear_range_values_in_range_array - return the amount of values in ranges + * @r: pointer to array of linear ranges where values are counted + * @ranges: amount of ranges we include in computation. + * + * Compute the amount of values in ranges pointed by @r. Note, values can + * be all equal - range with selectors 0,...,2 with step 0 still contains + * 3 values even though they are all equal. + * + * Return: the amount of values in first @ranges ranges pointed by @r + */ +unsigned int linear_range_values_in_range_array(const struct linear_range *r, + int ranges) +{ + int i, values_in_range = 0; + + for (i = 0; i < ranges; i++) { + int values; + + values = linear_range_values_in_range(&r[i]); + if (!values) + return values; + + values_in_range += values; + } + return values_in_range; +} +EXPORT_SYMBOL_GPL(linear_range_values_in_range_array); + +/** + * linear_range_get_max_value - return the largest value in a range + * @r: pointer to linear range where value is looked from + * + * Return: the largest value in the given range + */ +unsigned int linear_range_get_max_value(const struct linear_range *r) +{ + return r->min + (r->max_sel - r->min_sel) * r->step; +} +EXPORT_SYMBOL_GPL(linear_range_get_max_value); + +/** + * linear_range_get_value - fetch a value from given range + * @r: pointer to linear range where value is looked from + * @selector: selector for which the value is searched + * @val: address where found value is updated + * + * Search given ranges for value which matches given selector. + * + * Return: 0 on success, -EINVAL given selector is not found from any of the + * ranges. + */ +int linear_range_get_value(const struct linear_range *r, unsigned int selector, + unsigned int *val) +{ + if (r->min_sel > selector || r->max_sel < selector) + return -EINVAL; + + *val = r->min + (selector - r->min_sel) * r->step; + + return 0; +} +EXPORT_SYMBOL_GPL(linear_range_get_value); + +/** + * linear_range_get_value_array - fetch a value from array of ranges + * @r: pointer to array of linear ranges where value is looked from + * @ranges: amount of ranges in an array + * @selector: selector for which the value is searched + * @val: address where found value is updated + * + * Search through an array of ranges for value which matches given selector. + * + * Return: 0 on success, -EINVAL given selector is not found from any of the + * ranges. + */ +int linear_range_get_value_array(const struct linear_range *r, int ranges, + unsigned int selector, unsigned int *val) +{ + int i; + + for (i = 0; i < ranges; i++) + if (r[i].min_sel <= selector && r[i].max_sel >= selector) + return linear_range_get_value(&r[i], selector, val); + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(linear_range_get_value_array); + +/** + * linear_range_get_selector_low - return linear range selector for value + * @r: pointer to linear range where selector is looked from + * @val: value for which the selector is searched + * @selector: address where found selector value is updated + * @found: flag to indicate that given value was in the range + * + * Return selector which which range value is closest match for given + * input value. Value is matching if it is equal or smaller than given + * value. If given value is in the range, then @found is set true. + * + * Return: 0 on success, -EINVAL if range is invalid or does not contain + * value smaller or equal to given value + */ +int linear_range_get_selector_low(const struct linear_range *r, + unsigned int val, unsigned int *selector, + bool *found) +{ + *found = false; + + if (r->min > val) + return -EINVAL; + + if (linear_range_get_max_value(r) < val) { + *selector = r->max_sel; + return 0; + } + + *found = true; + + if (r->step == 0) + *selector = r->min_sel; + else + *selector = (val - r->min) / r->step + r->min_sel; + + return 0; +} +EXPORT_SYMBOL_GPL(linear_range_get_selector_low); + +/** + * linear_range_get_selector_low_array - return linear range selector for value + * @r: pointer to array of linear ranges where selector is looked from + * @ranges: amount of ranges to scan from array + * @val: value for which the selector is searched + * @selector: address where found selector value is updated + * @found: flag to indicate that given value was in the range + * + * Scan array of ranges for selector which which range value matches given + * input value. Value is matching if it is equal or smaller than given + * value. If given value is found to be in a range scanning is stopped and + * @found is set true. If a range with values smaller than given value is found + * but the range max is being smaller than given value, then the ranges + * biggest selector is updated to @selector but scanning ranges is continued + * and @found is set to false. + * + * Return: 0 on success, -EINVAL if range array is invalid or does not contain + * range with a value smaller or equal to given value + */ +int linear_range_get_selector_low_array(const struct linear_range *r, + int ranges, unsigned int val, + unsigned int *selector, bool *found) +{ + int i; + int ret = -EINVAL; + + for (i = 0; i < ranges; i++) { + int tmpret; + + tmpret = linear_range_get_selector_low(&r[i], val, selector, + found); + if (!tmpret) + ret = 0; + + if (*found) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(linear_range_get_selector_low_array); + +/** + * linear_range_get_selector_high - return linear range selector for value + * @r: pointer to linear range where selector is looked from + * @val: value for which the selector is searched + * @selector: address where found selector value is updated + * @found: flag to indicate that given value was in the range + * + * Return selector which which range value is closest match for given + * input value. Value is matching if it is equal or higher than given + * value. If given value is in the range, then @found is set true. + * + * Return: 0 on success, -EINVAL if range is invalid or does not contain + * value greater or equal to given value + */ +int linear_range_get_selector_high(const struct linear_range *r, + unsigned int val, unsigned int *selector, + bool *found) +{ + *found = false; + + if (linear_range_get_max_value(r) < val) + return -EINVAL; + + if (r->min > val) { + *selector = r->min_sel; + return 0; + } + + *found = true; + + if (r->step == 0) + *selector = r->max_sel; + else + *selector = DIV_ROUND_UP(val - r->min, r->step) + r->min_sel; + + return 0; +} +EXPORT_SYMBOL_GPL(linear_range_get_selector_high); + +MODULE_DESCRIPTION("linear-ranges helper"); +MODULE_LICENSE("GPL"); diff --git a/lib/test_linear_ranges.c b/lib/test_linear_ranges.c new file mode 100644 index 000000000000..676e0b8abcdd --- /dev/null +++ b/lib/test_linear_ranges.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for the linear_ranges helper. + * + * Copyright (C) 2020, ROHM Semiconductors. + * Author: Matti Vaittinen <matti.vaittien@fi.rohmeurope.com> + */ +#include <kunit/test.h> + +#include <linux/linear_range.h> + +/* First things first. I deeply dislike unit-tests. I have seen all the hell + * breaking loose when people who think the unit tests are "the silver bullet" + * to kill bugs get to decide how a company should implement testing strategy... + * + * Believe me, it may get _really_ ridiculous. It is tempting to think that + * walking through all the possible execution branches will nail down 100% of + * bugs. This may lead to ideas about demands to get certain % of "test + * coverage" - measured as line coverage. And that is one of the worst things + * you can do. + * + * Ask people to provide line coverage and they do. I've seen clever tools + * which generate test cases to test the existing functions - and by default + * these tools expect code to be correct and just generate checks which are + * passing when ran against current code-base. Run this generator and you'll get + * tests that do not test code is correct but just verify nothing changes. + * Problem is that testing working code is pointless. And if it is not + * working, your test must not assume it is working. You won't catch any bugs + * by such tests. What you can do is to generate a huge amount of tests. + * Especially if you were are asked to proivde 100% line-coverage x_x. So what + * does these tests - which are not finding any bugs now - do? + * + * They add inertia to every future development. I think it was Terry Pratchet + * who wrote someone having same impact as thick syrup has to chronometre. + * Excessive amount of unit-tests have this effect to development. If you do + * actually find _any_ bug from code in such environment and try fixing it... + * ...chances are you also need to fix the test cases. In sunny day you fix one + * test. But I've done refactoring which resulted 500+ broken tests (which had + * really zero value other than proving to managers that we do do "quality")... + * + * After this being said - there are situations where UTs can be handy. If you + * have algorithms which take some input and should produce output - then you + * can implement few, carefully selected simple UT-cases which test this. I've + * previously used this for example for netlink and device-tree data parsing + * functions. Feed some data examples to functions and verify the output is as + * expected. I am not covering all the cases but I will see the logic should be + * working. + * + * Here we also do some minor testing. I don't want to go through all branches + * or test more or less obvious things - but I want to see the main logic is + * working. And I definitely don't want to add 500+ test cases that break when + * some simple fix is done x_x. So - let's only add few, well selected tests + * which ensure as much logic is good as possible. + */ + +/* + * Test Range 1: + * selectors: 2 3 4 5 6 + * values (5): 10 20 30 40 50 + * + * Test Range 2: + * selectors: 7 8 9 10 + * values (4): 100 150 200 250 + */ + +#define RANGE1_MIN 10 +#define RANGE1_MIN_SEL 2 +#define RANGE1_STEP 10 + +/* 2, 3, 4, 5, 6 */ +static const unsigned int range1_sels[] = { RANGE1_MIN_SEL, RANGE1_MIN_SEL + 1, + RANGE1_MIN_SEL + 2, + RANGE1_MIN_SEL + 3, + RANGE1_MIN_SEL + 4 }; +/* 10, 20, 30, 40, 50 */ +static const unsigned int range1_vals[] = { RANGE1_MIN, RANGE1_MIN + + RANGE1_STEP, + RANGE1_MIN + RANGE1_STEP * 2, + RANGE1_MIN + RANGE1_STEP * 3, + RANGE1_MIN + RANGE1_STEP * 4 }; + +#define RANGE2_MIN 100 +#define RANGE2_MIN_SEL 7 +#define RANGE2_STEP 50 + +/* 7, 8, 9, 10 */ +static const unsigned int range2_sels[] = { RANGE2_MIN_SEL, RANGE2_MIN_SEL + 1, + RANGE2_MIN_SEL + 2, + RANGE2_MIN_SEL + 3 }; +/* 100, 150, 200, 250 */ +static const unsigned int range2_vals[] = { RANGE2_MIN, RANGE2_MIN + + RANGE2_STEP, + RANGE2_MIN + RANGE2_STEP * 2, + RANGE2_MIN + RANGE2_STEP * 3 }; + +#define RANGE1_NUM_VALS (ARRAY_SIZE(range1_vals)) +#define RANGE2_NUM_VALS (ARRAY_SIZE(range2_vals)) +#define RANGE_NUM_VALS (RANGE1_NUM_VALS + RANGE2_NUM_VALS) + +#define RANGE1_MAX_SEL (RANGE1_MIN_SEL + RANGE1_NUM_VALS - 1) +#define RANGE1_MAX_VAL (range1_vals[RANGE1_NUM_VALS - 1]) + +#define RANGE2_MAX_SEL (RANGE2_MIN_SEL + RANGE2_NUM_VALS - 1) +#define RANGE2_MAX_VAL (range2_vals[RANGE2_NUM_VALS - 1]) + +#define SMALLEST_SEL RANGE1_MIN_SEL +#define SMALLEST_VAL RANGE1_MIN + +static struct linear_range testr[] = { + { + .min = RANGE1_MIN, + .min_sel = RANGE1_MIN_SEL, + .max_sel = RANGE1_MAX_SEL, + .step = RANGE1_STEP, + }, { + .min = RANGE2_MIN, + .min_sel = RANGE2_MIN_SEL, + .max_sel = RANGE2_MAX_SEL, + .step = RANGE2_STEP + }, +}; + +static void range_test_get_value(struct kunit *test) +{ + int ret, i; + unsigned int sel, val; + + for (i = 0; i < RANGE1_NUM_VALS; i++) { + sel = range1_sels[i]; + ret = linear_range_get_value_array(&testr[0], 2, sel, &val); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, val, range1_vals[i]); + } + for (i = 0; i < RANGE2_NUM_VALS; i++) { + sel = range2_sels[i]; + ret = linear_range_get_value_array(&testr[0], 2, sel, &val); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, val, range2_vals[i]); + } + ret = linear_range_get_value_array(&testr[0], 2, sel + 1, &val); + KUNIT_EXPECT_NE(test, 0, ret); +} + +static void range_test_get_selector_high(struct kunit *test) +{ + int ret, i; + unsigned int sel; + bool found; + + for (i = 0; i < RANGE1_NUM_VALS; i++) { + ret = linear_range_get_selector_high(&testr[0], range1_vals[i], + &sel, &found); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, sel, range1_sels[i]); + KUNIT_EXPECT_TRUE(test, found); + } + + ret = linear_range_get_selector_high(&testr[0], RANGE1_MAX_VAL + 1, + &sel, &found); + KUNIT_EXPECT_LE(test, ret, 0); + + ret = linear_range_get_selector_high(&testr[0], RANGE1_MIN - 1, + &sel, &found); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_FALSE(test, found); + KUNIT_EXPECT_EQ(test, sel, range1_sels[0]); +} + +static void range_test_get_value_amount(struct kunit *test) +{ + int ret; + + ret = linear_range_values_in_range_array(&testr[0], 2); + KUNIT_EXPECT_EQ(test, (int)RANGE_NUM_VALS, ret); +} + +static void range_test_get_selector_low(struct kunit *test) +{ + int i, ret; + unsigned int sel; + bool found; + + for (i = 0; i < RANGE1_NUM_VALS; i++) { + ret = linear_range_get_selector_low_array(&testr[0], 2, + range1_vals[i], &sel, + &found); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, sel, range1_sels[i]); + KUNIT_EXPECT_TRUE(test, found); + } + for (i = 0; i < RANGE2_NUM_VALS; i++) { + ret = linear_range_get_selector_low_array(&testr[0], 2, + range2_vals[i], &sel, + &found); + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, sel, range2_sels[i]); + KUNIT_EXPECT_TRUE(test, found); + } + + /* + * Seek value greater than range max => get_selector_*_low should + * return Ok - but set found to false as value is not in range + */ + ret = linear_range_get_selector_low_array(&testr[0], 2, + range2_vals[RANGE2_NUM_VALS - 1] + 1, + &sel, &found); + + KUNIT_EXPECT_EQ(test, 0, ret); + KUNIT_EXPECT_EQ(test, sel, range2_sels[RANGE2_NUM_VALS - 1]); + KUNIT_EXPECT_FALSE(test, found); +} + +static struct kunit_case range_test_cases[] = { + KUNIT_CASE(range_test_get_value_amount), + KUNIT_CASE(range_test_get_selector_high), + KUNIT_CASE(range_test_get_selector_low), + KUNIT_CASE(range_test_get_value), + {}, +}; + +static struct kunit_suite range_test_module = { + .name = "linear-ranges-test", + .test_cases = range_test_cases, +}; + +kunit_test_suites(&range_test_module); + +MODULE_LICENSE("GPL"); |