// SPDX-License-Identifier: GPL-2.0+

  /*
   * Program for finding M & N values for DPLLs
   * To be run on Host PC
   *
   * (C) Copyright 2010
   * Texas Instruments, <www.ti.com>
   *
   * Aneesh V <aneesh@ti.com>

   */
  #include <stdlib.h>
  #include <stdio.h>
  typedef unsigned int u32;
  #define MAX_N	127
  
  /*
   * get_m_n_optimized() - Finds optimal DPLL multiplier(M) and divider(N)
   * values based on the reference frequency, required output frequency,
   * maximum tolerance for output frequency etc.
   *
   * target_freq_khz - output frequency required in KHz
   * ref_freq_khz - reference(input) frequency in KHz
   * m - pointer to computed M value
   * n - pointer to computed N value
   * tolerance_khz - tolerance for the output frequency. When the algorithm
   * succeeds in finding vialble M and N values the corresponding output
   * frequency will be in the range:
   *	[target_freq_khz - tolerance_khz, target_freq_khz]
   *
   * Formula:
   *	Fdpll = (2 * M * Fref) / (N + 1)
   *
   * Considerations for lock-time:
   *	- Smaller the N, better lock-time, especially lock-time will be
   *	- For acceptable lock-times:
   *		Fref / (M + 1) >= 1 MHz
   *
   * Considerations for power:
   *	- The difference in power for different N values giving the same
   *	  output is negligible. So, we optimize for lock-time
   *
   * Hard-constraints:
   *	- N can not be greater than 127(7 bit field for representing N)
   *
   * Usage:
   *	$ gcc clocks_get_m_n.c
   *	$ ./a.out
   */

  int get_m_n_optimized(u32 target_freq_khz, u32 ref_freq_khz, u32 *M, u32 *N)

  {

  	u32 freq = target_freq_khz;
  	u32 m_optimal, n_optimal, freq_optimal = 0, freq_old;
  	u32 m, n;
  	n = 1;

  	while (1) {

  		m = target_freq_khz / ref_freq_khz / 2 * n;

  		freq_old = 0;
  		while (1) {

  			freq = ref_freq_khz * 2 * m / n;
  			if (freq > target_freq_khz) {

  				freq = freq_old;

  				m--;

  				break;
  			}

  			m++;

  			freq_old = freq;
  		}

  		if (freq > freq_optimal) {
  			freq_optimal = freq;
  			m_optimal = m;
  			n_optimal = n;
  		}
  		n++;
  		if ((freq_optimal == target_freq_khz) ||
  			((ref_freq_khz / n) < 1000)) {

  			break;

  		}
  	}

  	n--;
  	*M = m_optimal;
  	*N = n_optimal - 1;
  	printf("ref %d m %d n %d target %d locked %d
  ", ref_freq_khz,
  		m_optimal, n_optimal - 1, target_freq_khz, freq_optimal);

  	return 0;
  }
  
  void main(void)
  {
  	u32 m, n;
  	printf("
  MPU - 2000000
  ");

  	get_m_n_optimized(2000000, 12000, &m, &n);
  	get_m_n_optimized(2000000, 13000, &m, &n);
  	get_m_n_optimized(2000000, 16800, &m, &n);
  	get_m_n_optimized(2000000, 19200, &m, &n);
  	get_m_n_optimized(2000000, 26000, &m, &n);
  	get_m_n_optimized(2000000, 27000, &m, &n);
  	get_m_n_optimized(2000000, 38400, &m, &n);

  
  	printf("
  MPU - 1200000
  ");

  	get_m_n_optimized(1200000, 12000, &m, &n);
  	get_m_n_optimized(1200000, 13000, &m, &n);
  	get_m_n_optimized(1200000, 16800, &m, &n);
  	get_m_n_optimized(1200000, 19200, &m, &n);
  	get_m_n_optimized(1200000, 26000, &m, &n);
  	get_m_n_optimized(1200000, 27000, &m, &n);
  	get_m_n_optimized(1200000, 38400, &m, &n);

  
  	printf("
  MPU - 1584000
  ");

  	get_m_n_optimized(1584000, 12000, &m, &n);
  	get_m_n_optimized(1584000, 13000, &m, &n);
  	get_m_n_optimized(1584000, 16800, &m, &n);
  	get_m_n_optimized(1584000, 19200, &m, &n);
  	get_m_n_optimized(1584000, 26000, &m, &n);
  	get_m_n_optimized(1584000, 27000, &m, &n);
  	get_m_n_optimized(1584000, 38400, &m, &n);

  
  	printf("
  Core 1600000
  ");

  	get_m_n_optimized(1600000, 12000, &m, &n);
  	get_m_n_optimized(1600000, 13000, &m, &n);
  	get_m_n_optimized(1600000, 16800, &m, &n);
  	get_m_n_optimized(1600000, 19200, &m, &n);
  	get_m_n_optimized(1600000, 26000, &m, &n);
  	get_m_n_optimized(1600000, 27000, &m, &n);
  	get_m_n_optimized(1600000, 38400, &m, &n);

  
  	printf("
  PER 1536000
  ");

  	get_m_n_optimized(1536000, 12000, &m, &n);
  	get_m_n_optimized(1536000, 13000, &m, &n);
  	get_m_n_optimized(1536000, 16800, &m, &n);
  	get_m_n_optimized(1536000, 19200, &m, &n);
  	get_m_n_optimized(1536000, 26000, &m, &n);
  	get_m_n_optimized(1536000, 27000, &m, &n);
  	get_m_n_optimized(1536000, 38400, &m, &n);

  
  	printf("
  IVA 1862000
  ");

  	get_m_n_optimized(1862000, 12000, &m, &n);
  	get_m_n_optimized(1862000, 13000, &m, &n);
  	get_m_n_optimized(1862000, 16800, &m, &n);
  	get_m_n_optimized(1862000, 19200, &m, &n);
  	get_m_n_optimized(1862000, 26000, &m, &n);
  	get_m_n_optimized(1862000, 27000, &m, &n);
  	get_m_n_optimized(1862000, 38400, &m, &n);
  
  	printf("
  IVA Nitro - 1290000
  ");
  	get_m_n_optimized(1290000, 12000, &m, &n);
  	get_m_n_optimized(1290000, 13000, &m, &n);
  	get_m_n_optimized(1290000, 16800, &m, &n);
  	get_m_n_optimized(1290000, 19200, &m, &n);
  	get_m_n_optimized(1290000, 26000, &m, &n);
  	get_m_n_optimized(1290000, 27000, &m, &n);
  	get_m_n_optimized(1290000, 38400, &m, &n);

  
  	printf("
  ABE 196608 sys clk
  ");

  	get_m_n_optimized(196608, 12000, &m, &n);
  	get_m_n_optimized(196608, 13000, &m, &n);
  	get_m_n_optimized(196608, 16800, &m, &n);
  	get_m_n_optimized(196608, 19200, &m, &n);
  	get_m_n_optimized(196608, 26000, &m, &n);
  	get_m_n_optimized(196608, 27000, &m, &n);
  	get_m_n_optimized(196608, 38400, &m, &n);

  
  	printf("
  ABE 196608 32K
  ");

  	get_m_n_optimized(196608000/4, 32768, &m, &n);

  
  	printf("
  USB 1920000
  ");

  	get_m_n_optimized(1920000, 12000, &m, &n);
  	get_m_n_optimized(1920000, 13000, &m, &n);
  	get_m_n_optimized(1920000, 16800, &m, &n);
  	get_m_n_optimized(1920000, 19200, &m, &n);
  	get_m_n_optimized(1920000, 26000, &m, &n);
  	get_m_n_optimized(1920000, 27000, &m, &n);
  	get_m_n_optimized(1920000, 38400, &m, &n);

  
  	printf("
  Core ES1 1523712
  ");

  	get_m_n_optimized(1524000, 12000, &m, &n);
  	get_m_n_optimized(1524000, 13000, &m, &n);
  	get_m_n_optimized(1524000, 16800, &m, &n);
  	get_m_n_optimized(1524000, 19200, &m, &n);
  	get_m_n_optimized(1524000, 26000, &m, &n);
  	get_m_n_optimized(1524000, 27000, &m, &n);

  
  	/* exact recommendation for SDPs */

  	get_m_n_optimized(1523712, 38400, &m, &n);

  
  }