Frank Oltmanns | 2790e2a3 | 2023-06-17 15:10:41 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
Jeff Johnson | 06abd44 | 2024-06-02 08:38:33 -0700 | [diff] [blame] | 3 | * Kunit tests for clk fractional divider |
Frank Oltmanns | 2790e2a3 | 2023-06-17 15:10:41 +0200 | [diff] [blame] | 4 | */ |
| 5 | #include <linux/clk-provider.h> |
| 6 | #include <kunit/test.h> |
| 7 | |
| 8 | #include "clk-fractional-divider.h" |
| 9 | |
| 10 | /* |
| 11 | * Test the maximum denominator case for fd clock without flags. |
| 12 | * |
| 13 | * Expect the highest possible denominator to be used in order to get as close as possible to the |
| 14 | * requested rate. |
| 15 | */ |
| 16 | static void clk_fd_test_approximation_max_denominator(struct kunit *test) |
| 17 | { |
| 18 | struct clk_fractional_divider *fd; |
| 19 | unsigned long rate, parent_rate, parent_rate_before, m, n, max_n; |
| 20 | |
| 21 | fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL); |
| 22 | KUNIT_ASSERT_NOT_NULL(test, fd); |
| 23 | |
| 24 | fd->mwidth = 3; |
| 25 | fd->nwidth = 3; |
| 26 | max_n = 7; |
| 27 | |
| 28 | rate = 240000000; |
| 29 | parent_rate = (max_n + 1) * rate; /* so that it exceeds the maximum divisor */ |
| 30 | parent_rate_before = parent_rate; |
| 31 | |
| 32 | clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n); |
| 33 | KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before); |
| 34 | |
| 35 | KUNIT_EXPECT_EQ(test, m, 1); |
| 36 | KUNIT_EXPECT_EQ(test, n, max_n); |
| 37 | } |
| 38 | |
| 39 | /* |
| 40 | * Test the maximum numerator case for fd clock without flags. |
| 41 | * |
| 42 | * Expect the highest possible numerator to be used in order to get as close as possible to the |
| 43 | * requested rate. |
| 44 | */ |
| 45 | static void clk_fd_test_approximation_max_numerator(struct kunit *test) |
| 46 | { |
| 47 | struct clk_fractional_divider *fd; |
| 48 | unsigned long rate, parent_rate, parent_rate_before, m, n, max_m; |
| 49 | |
| 50 | fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL); |
| 51 | KUNIT_ASSERT_NOT_NULL(test, fd); |
| 52 | |
| 53 | fd->mwidth = 3; |
| 54 | max_m = 7; |
| 55 | fd->nwidth = 3; |
| 56 | |
| 57 | rate = 240000000; |
| 58 | parent_rate = rate / (max_m + 1); /* so that it exceeds the maximum numerator */ |
| 59 | parent_rate_before = parent_rate; |
| 60 | |
| 61 | clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n); |
| 62 | KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before); |
| 63 | |
| 64 | KUNIT_EXPECT_EQ(test, m, max_m); |
| 65 | KUNIT_EXPECT_EQ(test, n, 1); |
| 66 | } |
| 67 | |
| 68 | /* |
| 69 | * Test the maximum denominator case for zero based fd clock. |
| 70 | * |
| 71 | * Expect the highest possible denominator to be used in order to get as close as possible to the |
| 72 | * requested rate. |
| 73 | */ |
| 74 | static void clk_fd_test_approximation_max_denominator_zero_based(struct kunit *test) |
| 75 | { |
| 76 | struct clk_fractional_divider *fd; |
| 77 | unsigned long rate, parent_rate, parent_rate_before, m, n, max_n; |
| 78 | |
| 79 | fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL); |
| 80 | KUNIT_ASSERT_NOT_NULL(test, fd); |
| 81 | |
| 82 | fd->flags = CLK_FRAC_DIVIDER_ZERO_BASED; |
| 83 | fd->mwidth = 3; |
| 84 | fd->nwidth = 3; |
| 85 | max_n = 8; |
| 86 | |
| 87 | rate = 240000000; |
| 88 | parent_rate = (max_n + 1) * rate; /* so that it exceeds the maximum divisor */ |
| 89 | parent_rate_before = parent_rate; |
| 90 | |
| 91 | clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n); |
| 92 | KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before); |
| 93 | |
| 94 | KUNIT_EXPECT_EQ(test, m, 1); |
| 95 | KUNIT_EXPECT_EQ(test, n, max_n); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Test the maximum numerator case for zero based fd clock. |
| 100 | * |
| 101 | * Expect the highest possible numerator to be used in order to get as close as possible to the |
| 102 | * requested rate. |
| 103 | */ |
| 104 | static void clk_fd_test_approximation_max_numerator_zero_based(struct kunit *test) |
| 105 | { |
| 106 | struct clk_fractional_divider *fd; |
| 107 | unsigned long rate, parent_rate, parent_rate_before, m, n, max_m; |
| 108 | |
| 109 | fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL); |
| 110 | KUNIT_ASSERT_NOT_NULL(test, fd); |
| 111 | |
| 112 | fd->flags = CLK_FRAC_DIVIDER_ZERO_BASED; |
| 113 | fd->mwidth = 3; |
| 114 | max_m = 8; |
| 115 | fd->nwidth = 3; |
| 116 | |
| 117 | rate = 240000000; |
| 118 | parent_rate = rate / (max_m + 1); /* so that it exceeds the maximum numerator */ |
| 119 | parent_rate_before = parent_rate; |
| 120 | |
| 121 | clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n); |
| 122 | KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before); |
| 123 | |
| 124 | KUNIT_EXPECT_EQ(test, m, max_m); |
| 125 | KUNIT_EXPECT_EQ(test, n, 1); |
| 126 | } |
| 127 | |
| 128 | static struct kunit_case clk_fd_approximation_test_cases[] = { |
| 129 | KUNIT_CASE(clk_fd_test_approximation_max_denominator), |
| 130 | KUNIT_CASE(clk_fd_test_approximation_max_numerator), |
| 131 | KUNIT_CASE(clk_fd_test_approximation_max_denominator_zero_based), |
| 132 | KUNIT_CASE(clk_fd_test_approximation_max_numerator_zero_based), |
| 133 | {} |
| 134 | }; |
| 135 | |
| 136 | /* |
| 137 | * Test suite for clk_fractional_divider_general_approximation(). |
| 138 | */ |
| 139 | static struct kunit_suite clk_fd_approximation_suite = { |
| 140 | .name = "clk-fd-approximation", |
| 141 | .test_cases = clk_fd_approximation_test_cases, |
| 142 | }; |
| 143 | |
| 144 | kunit_test_suites( |
| 145 | &clk_fd_approximation_suite |
| 146 | ); |
Jeff Johnson | 06abd44 | 2024-06-02 08:38:33 -0700 | [diff] [blame] | 147 | MODULE_DESCRIPTION("Kunit tests for clk fractional divider"); |
Frank Oltmanns | 2790e2a3 | 2023-06-17 15:10:41 +0200 | [diff] [blame] | 148 | MODULE_LICENSE("GPL"); |