summaryrefslogtreecommitdiff
path: root/tools/omap/clocks_get_m_n.c
blob: e21b0e2b60b6b7c26476eb57162f58a23eaa0934 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
// 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);

}