LXR uboot/tools/omap/clocks_get_m

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Program for finding M & N values for DPLLs
   4 * To be run on Host PC
   5 *
   6 * (C) Copyright 2010
   7 * Texas Instruments, <www.ti.com>
   8 *
   9 * Aneesh V <aneesh@ti.com>
  10 */
  11#include <stdlib.h>
  12#include <stdio.h>
  13typedef unsigned int u32;
  14#define MAX_N   127
  15
  16/*
  17 * get_m_n_optimized() - Finds optimal DPLL multiplier(M) and divider(N)
  18 * values based on the reference frequency, required output frequency,
  19 * maximum tolerance for output frequency etc.
  20 *
  21 * target_freq_khz - output frequency required in KHz
  22 * ref_freq_khz - reference(input) frequency in KHz
  23 * m - pointer to computed M value
  24 * n - pointer to computed N value
  25 * tolerance_khz - tolerance for the output frequency. When the algorithm
  26 * succeeds in finding vialble M and N values the corresponding output
  27 * frequency will be in the range:
  28 *      [target_freq_khz - tolerance_khz, target_freq_khz]
  29 *
  30 * Formula:
  31 *      Fdpll = (2 * M * Fref) / (N + 1)
  32 *
  33 * Considerations for lock-time:
  34 *      - Smaller the N, better lock-time, especially lock-time will be
  35 *      - For acceptable lock-times:
  36 *              Fref / (M + 1) >= 1 MHz
  37 *
  38 * Considerations for power:
  39 *      - The difference in power for different N values giving the same
  40 *        output is negligible. So, we optimize for lock-time
  41 *
  42 * Hard-constraints:
  43 *      - N can not be greater than 127(7 bit field for representing N)
  44 *
  45 * Usage:
  46 *      $ gcc clocks_get_m_n.c
  47 *      $ ./a.out
  48 */
  49int get_m_n_optimized(u32 target_freq_khz, u32 ref_freq_khz, u32 *M, u32 *N)
  50{
  51        u32 freq = target_freq_khz;
  52        u32 m_optimal, n_optimal, freq_optimal = 0, freq_old;
  53        u32 m, n;
  54        n = 1;
  55        while (1) {
  56                m = target_freq_khz / ref_freq_khz / 2 * n;
  57                freq_old = 0;
  58                while (1) {
  59                        freq = ref_freq_khz * 2 * m / n;
  60                        if (freq > target_freq_khz) {
  61                                freq = freq_old;
  62                                m--;
  63                                break;
  64                        }
  65                        m++;
  66                        freq_old = freq;
  67                }
  68                if (freq > freq_optimal) {
  69                        freq_optimal = freq;
  70                        m_optimal = m;
  71                        n_optimal = n;
  72                }
  73                n++;
  74                if ((freq_optimal == target_freq_khz) ||
  75                        ((ref_freq_khz / n) < 1000)) {
  76                        break;
  77                }
  78        }
  79        n--;
  80        *M = m_optimal;
  81        *N = n_optimal - 1;
  82        printf("ref %d m %d n %d target %d locked %d\n", ref_freq_khz,
  83                m_optimal, n_optimal - 1, target_freq_khz, freq_optimal);
  84        return 0;
  85}
  86
  87void main(void)
  88{
  89        u32 m, n;
  90        printf("\nMPU - 2000000\n");
  91        get_m_n_optimized(2000000, 12000, &m, &n);
  92        get_m_n_optimized(2000000, 13000, &m, &n);
  93        get_m_n_optimized(2000000, 16800, &m, &n);
  94        get_m_n_optimized(2000000, 19200, &m, &n);
  95        get_m_n_optimized(2000000, 26000, &m, &n);
  96        get_m_n_optimized(2000000, 27000, &m, &n);
  97        get_m_n_optimized(2000000, 38400, &m, &n);
  98
  99        printf("\nMPU - 1200000\n");
 100        get_m_n_optimized(1200000, 12000, &m, &n);
 101        get_m_n_optimized(1200000, 13000, &m, &n);
 102        get_m_n_optimized(1200000, 16800, &m, &n);
 103        get_m_n_optimized(1200000, 19200, &m, &n);
 104        get_m_n_optimized(1200000, 26000, &m, &n);
 105        get_m_n_optimized(1200000, 27000, &m, &n);
 106        get_m_n_optimized(1200000, 38400, &m, &n);
 107
 108        printf("\nMPU - 1584000\n");
 109        get_m_n_optimized(1584000, 12000, &m, &n);
 110        get_m_n_optimized(1584000, 13000, &m, &n);
 111        get_m_n_optimized(1584000, 16800, &m, &n);
 112        get_m_n_optimized(1584000, 19200, &m, &n);
 113        get_m_n_optimized(1584000, 26000, &m, &n);
 114        get_m_n_optimized(1584000, 27000, &m, &n);
 115        get_m_n_optimized(1584000, 38400, &m, &n);
 116
 117        printf("\nCore 1600000\n");
 118        get_m_n_optimized(1600000, 12000, &m, &n);
 119        get_m_n_optimized(1600000, 13000, &m, &n);
 120        get_m_n_optimized(1600000, 16800, &m, &n);
 121        get_m_n_optimized(1600000, 19200, &m, &n);
 122        get_m_n_optimized(1600000, 26000, &m, &n);
 123        get_m_n_optimized(1600000, 27000, &m, &n);
 124        get_m_n_optimized(1600000, 38400, &m, &n);
 125
 126        printf("\nPER 1536000\n");
 127        get_m_n_optimized(1536000, 12000, &m, &n);
 128        get_m_n_optimized(1536000, 13000, &m, &n);
 129        get_m_n_optimized(1536000, 16800, &m, &n);
 130        get_m_n_optimized(1536000, 19200, &m, &n);
 131        get_m_n_optimized(1536000, 26000, &m, &n);
 132        get_m_n_optimized(1536000, 27000, &m, &n);
 133        get_m_n_optimized(1536000, 38400, &m, &n);
 134
 135        printf("\nIVA 1862000\n");
 136        get_m_n_optimized(1862000, 12000, &m, &n);
 137        get_m_n_optimized(1862000, 13000, &m, &n);
 138        get_m_n_optimized(1862000, 16800, &m, &n);
 139        get_m_n_optimized(1862000, 19200, &m, &n);
 140        get_m_n_optimized(1862000, 26000, &m, &n);
 141        get_m_n_optimized(1862000, 27000, &m, &n);
 142        get_m_n_optimized(1862000, 38400, &m, &n);
 143
 144        printf("\nIVA Nitro - 1290000\n");
 145        get_m_n_optimized(1290000, 12000, &m, &n);
 146        get_m_n_optimized(1290000, 13000, &m, &n);
 147        get_m_n_optimized(1290000, 16800, &m, &n);
 148        get_m_n_optimized(1290000, 19200, &m, &n);
 149        get_m_n_optimized(1290000, 26000, &m, &n);
 150        get_m_n_optimized(1290000, 27000, &m, &n);
 151        get_m_n_optimized(1290000, 38400, &m, &n);
 152
 153        printf("\nABE 196608 sys clk\n");
 154        get_m_n_optimized(196608, 12000, &m, &n);
 155        get_m_n_optimized(196608, 13000, &m, &n);
 156        get_m_n_optimized(196608, 16800, &m, &n);
 157        get_m_n_optimized(196608, 19200, &m, &n);
 158        get_m_n_optimized(196608, 26000, &m, &n);
 159        get_m_n_optimized(196608, 27000, &m, &n);
 160        get_m_n_optimized(196608, 38400, &m, &n);
 161
 162        printf("\nABE 196608 32K\n");
 163        get_m_n_optimized(196608000/4, 32768, &m, &n);
 164
 165        printf("\nUSB 1920000\n");
 166        get_m_n_optimized(1920000, 12000, &m, &n);
 167        get_m_n_optimized(1920000, 13000, &m, &n);
 168        get_m_n_optimized(1920000, 16800, &m, &n);
 169        get_m_n_optimized(1920000, 19200, &m, &n);
 170        get_m_n_optimized(1920000, 26000, &m, &n);
 171        get_m_n_optimized(1920000, 27000, &m, &n);
 172        get_m_n_optimized(1920000, 38400, &m, &n);
 173
 174        printf("\nCore ES1 1523712\n");
 175        get_m_n_optimized(1524000, 12000, &m, &n);
 176        get_m_n_optimized(1524000, 13000, &m, &n);
 177        get_m_n_optimized(1524000, 16800, &m, &n);
 178        get_m_n_optimized(1524000, 19200, &m, &n);
 179        get_m_n_optimized(1524000, 26000, &m, &n);
 180        get_m_n_optimized(1524000, 27000, &m, &n);
 181
 182        /* exact recommendation for SDPs */
 183        get_m_n_optimized(1523712, 38400, &m, &n);
 184
 185}
 186