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u-boot/tools/omap/clocks_get_m_n.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

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// 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\n", ref_freq_khz,
m_optimal, n_optimal - 1, target_freq_khz, freq_optimal);
return 0;
}
void main(void)
{
u32 m, n;
printf("\nMPU - 2000000\n");
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("\nMPU - 1200000\n");
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("\nMPU - 1584000\n");
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("\nCore 1600000\n");
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("\nPER 1536000\n");
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("\nIVA 1862000\n");
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("\nIVA Nitro - 1290000\n");
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("\nABE 196608 sys clk\n");
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("\nABE 196608 32K\n");
get_m_n_optimized(196608000/4, 32768, &m, &n);
printf("\nUSB 1920000\n");
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("\nCore ES1 1523712\n");
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);
}
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