LXR uboot/test/dm/k210

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
   4 */
   5
   6#include <common.h>
   7/* For DIV_ROUND_DOWN_ULL, defined in linux/kernel.h */
   8#include <div64.h>
   9#include <dm/test.h>
  10#include <kendryte/pll.h>
  11#include <test/ut.h>
  12
  13static int dm_test_k210_pll_calc_config(u32 rate, u32 rate_in,
  14                                        struct k210_pll_config *best)
  15{
  16        u64 f, r, od, max_r, inv_ratio;
  17        s64 error, best_error;
  18
  19        best_error = S64_MAX;
  20        error = best_error;
  21        max_r = min(16ULL, DIV_ROUND_DOWN_ULL(rate_in, 13300000));
  22        inv_ratio = DIV_ROUND_CLOSEST_ULL((u64)rate_in << 32, rate);
  23
  24        /* Brute force it */
  25        for (r = 1; r <= max_r; r++) {
  26                for (f = 1; f <= 64; f++) {
  27                        for (od = 1; od <= 16; od++) {
  28                                u64 vco = DIV_ROUND_CLOSEST_ULL(rate_in * f, r);
  29
  30                                if (vco > 1750000000 || vco < 340000000)
  31                                        continue;
  32
  33                                error = DIV_ROUND_CLOSEST_ULL(f * inv_ratio,
  34                                                              r * od);
  35                                /* The lower 16 bits are spurious */
  36                                error = abs((error - BIT(32))) >> 16;
  37                                if (error < best_error) {
  38                                        best->r = r;
  39                                        best->f = f;
  40                                        best->od = od;
  41                                        best_error = error;
  42                                }
  43                        }
  44                }
  45        }
  46
  47        if (best_error == S64_MAX)
  48                return -EINVAL;
  49        return 0;
  50}
  51
  52static int dm_test_k210_pll_compare(struct k210_pll_config *ours,
  53                                    struct k210_pll_config *theirs)
  54{
  55        return (u32)ours->f * theirs->r * theirs->od !=
  56               (u32)theirs->f * ours->r * ours->od;
  57}
  58
  59static int dm_test_k210_pll(struct unit_test_state *uts)
  60{
  61        struct k210_pll_config ours, theirs;
  62
  63        /* General range checks */
  64        ut_asserteq(-EINVAL, k210_pll_calc_config(0, 26000000, &theirs));
  65        ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 0, &theirs));
  66        ut_asserteq(-EINVAL, k210_pll_calc_config(2000000000, 26000000,
  67                                                  &theirs));
  68        ut_asserteq(-EINVAL, k210_pll_calc_config(390000000, 2000000000,
  69                                                  &theirs));
  70        ut_asserteq(-EINVAL, k210_pll_calc_config(1500000000, 20000000,
  71                                                  &theirs));
  72        ut_asserteq(-EINVAL, k210_pll_calc_config(1750000000, 13300000,
  73                                                  &theirs));
  74
  75        /* Verify we get the same output with brute-force */
  76#define compare(rate, rate_in) do { \
  77        ut_assertok(dm_test_k210_pll_calc_config(rate, rate_in, &ours)); \
  78        ut_assertok(k210_pll_calc_config(rate, rate_in, &theirs)); \
  79        ut_assertok(dm_test_k210_pll_compare(&ours, &theirs)); \
  80} while (0)
  81
  82        compare(390000000, 26000000);
  83        compare(26000000, 390000000);
  84        compare(400000000, 26000000);
  85        compare(27000000, 26000000);
  86        compare(26000000, 27000000);
  87        compare(13300000 * 64, 13300000);
  88        compare(21250000, 21250000 * 70);
  89        compare(21250000, 1750000000);
  90        compare(1750000000, 1750000000);
  91
  92        return 0;
  93}
  94DM_TEST(dm_test_k210_pll, 0);
  95