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git01.mediatek.com / filogic / uboot / 9e11b66a6e32bad147f2c92ea677e450bf981687 / . / test / dm / k210_pll.c
blob: 2a581499634d3284660881e15bd4b1b6f15cf17b [file] [log] [blame]
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
4 */
5
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]6/* For DIV_ROUND_DOWN_ULL, defined in linux/kernel.h */
7#include <div64.h>
8#include <dm/test.h>
Damien Le Moal6e5a8b72022-03-01 10:35:39 +0000[diff] [blame]9#include <k210/pll.h>
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]10#include <test/ut.h>
11
12static int dm_test_k210_pll_calc_config(u32 rate, u32 rate_in,
13 struct k210_pll_config *best)
14{
15 u64 f, r, od, max_r, inv_ratio;
16 s64 error, best_error;
17
18 best_error = S64_MAX;
19 error = best_error;
20 max_r = min(16ULL, DIV_ROUND_DOWN_ULL(rate_in, 13300000));
21 inv_ratio = DIV_ROUND_CLOSEST_ULL((u64)rate_in << 32, rate);
22
23 /* Brute force it */
24 for (r = 1; r <= max_r; r++) {
25 for (f = 1; f <= 64; f++) {
26 for (od = 1; od <= 16; od++) {
27 u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
28
29 if (vco > 1750000000 || vco < 340000000)
30 continue;
31
32 error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio,
33 r * od);
34 /* The lower 16 bits are spurious */
Heinrich Schuchardt135e5f62022-10-16 18:12:32 +0200[diff] [blame]35 error = abs64((error - BIT_ULL(32))) >> 16;
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]36 if (error < best_error) {
37 best->r = r;
38 best->f = f;
39 best->od = od;
40 best_error = error;
41 }
42 }
43 }
44 }
45
46 if (best_error == S64_MAX)
47 return -EINVAL;
48 return 0;
49}
50
51static int dm_test_k210_pll_compare(struct k210_pll_config *ours,
52 struct k210_pll_config *theirs)
53{
54 return (u32)ours->f * theirs->r * theirs->od !=
55 (u32)theirs->f * ours->r * ours->od;
56}
57
58static int dm_test_k210_pll(struct unit_test_state *uts)
59{
60 struct k210_pll_config ours, theirs;
61
62 /* General range checks */
63 ut_asserteq(-EINVAL, k210_pll_calc_config(0, 26000000, &theirs));
64 ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 0, &theirs));
65 ut_asserteq(-EINVAL, k210_pll_calc_config(2000000000, 26000000,
66 &theirs));
67 ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 2000000000,
68 &theirs));
69 ut_asserteq(-EINVAL, k210_pll_calc_config(1500000000, 20000000,
70 &theirs));
Sean Andersone850b4c2021-09-11 13:20:02 -0400[diff] [blame]71 ut_asserteq(-EINVAL, k210_pll_calc_config(1750000000, 13300000,
72 &theirs));
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]73
74 /* Verify we get the same output with brute-force */
Sean Andersone850b4c2021-09-11 13:20:02 -0400[diff] [blame]75#define compare(rate, rate_in) do { \
76 ut_assertok(dm_test_k210_pll_calc_config(rate, rate_in, &ours)); \
77 ut_assertok(k210_pll_calc_config(rate, rate_in, &theirs)); \
78 ut_assertok(dm_test_k210_pll_compare(&ours, &theirs)); \
79} while (0)
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]80
Sean Andersone850b4c2021-09-11 13:20:02 -0400[diff] [blame]81 compare(390000000, 26000000);
82 compare(26000000, 390000000);
83 compare(400000000, 26000000);
84 compare(27000000, 26000000);
85 compare(26000000, 27000000);
Sean Andersone72139e2021-09-11 13:20:03 -0400[diff] [blame]86 compare(13300000 * 64, 13300000);
87 compare(21250000, 21250000 * 70);
88 compare(21250000, 1750000000);
89 compare(1750000000, 1750000000);
Sean Anderson6e887ee2020-06-24 06:41:09 -0400[diff] [blame]90
91 return 0;
92}
93DM_TEST(dm_test_k210_pll, 0);