mpc86x_clk.c
4.36 KB
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/*
* (C) Copyright 2003 Intracom S.A.
* Pantelis Antoniou <panto@intracom.gr>
*
* This little program makes an exhaustive search for the
* correct terms of pdf, mfi, mfn, mfd, s, dbrmo, in PLPRCR.
* The goal is to produce a gclk2 from a xin input, while respecting
* all the restrictions on their combination.
*
* Generaly you select the first row of the produced table.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <stdio.h>
#include <stdlib.h>
#define DPREF_MIN 10000000
#define DPREF_MAX 32000000
#define DPGDCK_MAX 320000000
#define DPGDCK_MIN 160000000
#define S_MIN 0
#define S_MAX 2
#define MFI_MIN 5
#define MFI_MAX 15
#define MFN_MIN 0
#define MFN_MAX 15
#define MFD_MIN 0
#define MFD_MAX 31
#define MF_MIN 5
#define MF_MAX 15
#define PDF_MIN 0
#define PDF_MAX 15
#define GCLK2_MAX 150000000
static int calculate (int xin, int target_clock,
int ppm, int pdf, int mfi, int mfn, int mfd, int s,
int *dprefp, int *dpgdckp, int *jdbckp,
int *gclk2p, int *dbrmop)
{
unsigned int dpref, dpgdck, jdbck, gclk2, t1, t2, dbrmo;
/* valid MFI? */
if (mfi < MFI_MIN)
return -1;
/* valid num, denum? */
if (mfn > 0 && mfn >= mfd)
return -1;
dpref = xin / (pdf + 1);
/* valid dpef? */
if (dpref < DPREF_MIN || dpref > DPREF_MAX)
return -1;
if (mfn == 0) {
dpgdck = (2 * mfi * xin) / (pdf + 1) ;
dbrmo = 0;
} else {
/* 5 <= mfi + (mfn / mfd + 1) <= 15 */
t1 = mfd + 1;
t2 = mfi * t1 + mfn;
if ( MF_MIN * t1 > t2 || MF_MAX * t1 < t2)
return -1;
dpgdck = (unsigned int)(2 * (mfi * mfd + mfi + mfn) *
(unsigned int)xin) /
((mfd + 1) * (pdf + 1));
dbrmo = 10 * mfn < (mfd + 1);
}
/* valid dpgclk? */
if (dpgdck < DPGDCK_MIN || dpgdck > DPGDCK_MAX)
return -1;
jdbck = dpgdck >> s;
gclk2 = jdbck / 2;
/* valid gclk2 */
if (gclk2 > GCLK2_MAX)
return -1;
t1 = abs(gclk2 - target_clock);
/* XXX max 1MHz dev. in clock */
if (t1 > 1000000)
return -1;
/* dev within range (XXX gclk2 scaled to avoid overflow) */
if (t1 * 1000 > (unsigned int)ppm * (gclk2 / 1000))
return -1;
*dprefp = dpref;
*dpgdckp = dpgdck;
*jdbckp = jdbck;
*gclk2p = gclk2;
*dbrmop = dbrmo;
return gclk2;
}
int conf_clock(int xin, int target_clock, int ppm)
{
int pdf, s, mfn, mfd, mfi;
int dpref, dpgdck, jdbck, gclk2, xout, dbrmo;
int found = 0;
/* integer multipliers */
for (pdf = PDF_MIN; pdf <= PDF_MAX; pdf++) {
for (mfi = MFI_MIN; mfi <= MFI_MAX; mfi++) {
for (s = 0; s <= S_MAX; s++) {
xout = calculate(xin, target_clock,
ppm, pdf, mfi, 0, 0, s,
&dpref, &dpgdck, &jdbck,
&gclk2, &dbrmo);
if (xout < 0)
continue;
if (found == 0) {
printf("pdf mfi mfn mfd s dbrmo dpref dpgdck jdbck gclk2 exact?\n");
printf("--- --- --- --- - ----- ----- ------ ----- ----- ------\n");
}
printf("%3d %3d --- --- %1d %5d %9d %9d %9d %9d%s\n",
pdf, mfi, s, dbrmo,
dpref, dpgdck, jdbck, gclk2,
gclk2 == target_clock ? " YES" : "");
found++;
}
}
}
/* fractional multipliers */
for (pdf = PDF_MIN; pdf <= PDF_MAX; pdf++) {
for (mfi = MFI_MIN; mfi <= MFI_MAX; mfi++) {
for (mfn = 1; mfn <= MFN_MAX; mfn++) {
for (mfd = 1; mfd <= MFD_MAX; mfd++) {
for (s = 0; s <= S_MAX; s++) {
xout = calculate(xin, target_clock,
ppm, pdf, mfi, mfn, mfd, s,
&dpref, &dpgdck, &jdbck,
&gclk2, &dbrmo);
if (xout < 0)
continue;
if (found == 0) {
printf("pdf mfi mfn mfd s dbrmo dpref dpgdck jdbck gclk2 exact?\n");
printf("--- --- --- --- - ----- ----- ------ ----- ----- ------\n");
}
printf("%3d %3d %3d %3d %1d %5d %9d %9d %9d %9d%s\n",
pdf, mfi, mfn, mfd, s,
dbrmo, dpref, dpgdck, jdbck, gclk2,
gclk2 == target_clock ? " YES" : "");
found++;
}
}
}
}
}
return found;
}
int main(int argc, char *argv[])
{
int xin, want_gclk2, found, ppm = 100;
if (argc < 3) {
fprintf(stderr, "usage: mpc86x_clk <xin> <want_gclk2> [ppm]\n");
fprintf(stderr, " default ppm is 100\n");
return 10;
}
xin = atoi(argv[1]);
want_gclk2 = atoi(argv[2]);
if (argc >= 4)
ppm = atoi(argv[3]);
found = conf_clock(xin, want_gclk2, ppm);
if (found <= 0) {
fprintf(stderr, "cannot produce gclk2 %d from xin %d\n",
want_gclk2, xin);
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}