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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
- */
- #include <common.h>
- /* For DIV_ROUND_DOWN_ULL, defined in linux/kernel.h */
- #include <div64.h>
- #include <dm/test.h>
- #include <kendryte/pll.h>
- #include <test/ut.h>
- static int dm_test_k210_pll_calc_config(u32 rate, u32 rate_in,
- struct k210_pll_config *best)
- {
- u64 f, r, od, max_r, inv_ratio;
- s64 error, best_error;
- best_error = S64_MAX;
- error = best_error;
- max_r = min(16ULL, DIV_ROUND_DOWN_ULL(rate_in, 13300000));
- inv_ratio = DIV_ROUND_CLOSEST_ULL((u64)rate_in << 32, rate);
- /* Brute force it */
- for (r = 1; r <= max_r; r++) {
- for (f = 1; f <= 64; f++) {
- for (od = 1; od <= 16; od++) {
- u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
- if (vco > 1750000000 || vco < 340000000)
- continue;
- error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio,
- r * od);
- /* The lower 16 bits are spurious */
- error = abs((error - BIT(32))) >> 16;
- if (error < best_error) {
- best->r = r;
- best->f = f;
- best->od = od;
- best_error = error;
- }
- }
- }
- }
- if (best_error == S64_MAX)
- return -EINVAL;
- return 0;
- }
- static int dm_test_k210_pll_compare(struct k210_pll_config *ours,
- struct k210_pll_config *theirs)
- {
- return (u32)ours->f * theirs->r * theirs->od !=
- (u32)theirs->f * ours->r * ours->od;
- }
- static int dm_test_k210_pll(struct unit_test_state *uts)
- {
- struct k210_pll_config ours, theirs;
- /* General range checks */
- ut_asserteq(-EINVAL, k210_pll_calc_config(0, 26000000, &theirs));
- ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 0, &theirs));
- ut_asserteq(-EINVAL, k210_pll_calc_config(2000000000, 26000000,
- &theirs));
- ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 2000000000,
- &theirs));
- ut_asserteq(-EINVAL, k210_pll_calc_config(1500000000, 20000000,
- &theirs));
- /* Verify we get the same output with brute-force */
- ut_assertok(dm_test_k210_pll_calc_config(390000000, 26000000, &ours));
- ut_assertok(k210_pll_calc_config(390000000, 26000000, &theirs));
- ut_assertok(dm_test_k210_pll_compare(&ours, &theirs));
- ut_assertok(dm_test_k210_pll_calc_config(26000000, 390000000, &ours));
- ut_assertok(k210_pll_calc_config(26000000, 390000000, &theirs));
- ut_assertok(dm_test_k210_pll_compare(&ours, &theirs));
- ut_assertok(dm_test_k210_pll_calc_config(400000000, 26000000, &ours));
- ut_assertok(k210_pll_calc_config(400000000, 26000000, &theirs));
- ut_assertok(dm_test_k210_pll_compare(&ours, &theirs));
- ut_assertok(dm_test_k210_pll_calc_config(27000000, 26000000, &ours));
- ut_assertok(k210_pll_calc_config(27000000, 26000000, &theirs));
- ut_assertok(dm_test_k210_pll_compare(&ours, &theirs));
- ut_assertok(dm_test_k210_pll_calc_config(26000000, 27000000, &ours));
- ut_assertok(k210_pll_calc_config(26000000, 27000000, &theirs));
- ut_assertok(dm_test_k210_pll_compare(&ours, &theirs));
- return 0;
- }
- DM_TEST(dm_test_k210_pll, 0);
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