mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 08:36:43 +07:00
e972c37459
Since the dawn of time the ICST code has only supported divide by one or hang in an eternal loop. Luckily we were always dividing by one because the reference frequency for the systems using the ICSTs is 24MHz and the [min,max] values for the PLL input if [10,320] MHz for ICST307 and [6,200] for ICST525, so the loop will always terminate immediately without assigning any divisor for the reference frequency. But for the code to make sense, let's insert the missing i++ Reported-by: David Binderman <dcb314@hotmail.com> Cc: stable@vger.kernel.org Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
|
|
* linux/arch/arm/common/icst307.c
|
|
*
|
|
* Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* Support functions for calculating clocks/divisors for the ICST307
|
|
* clock generators. See http://www.idt.com/ for more information
|
|
* on these devices.
|
|
*
|
|
* This is an almost identical implementation to the ICST525 clock generator.
|
|
* The s2div and idx2s files are different
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <asm/div64.h>
|
|
#include <asm/hardware/icst.h>
|
|
|
|
/*
|
|
* Divisors for each OD setting.
|
|
*/
|
|
const unsigned char icst307_s2div[8] = { 10, 2, 8, 4, 5, 7, 3, 6 };
|
|
const unsigned char icst525_s2div[8] = { 10, 2, 8, 4, 5, 7, 9, 6 };
|
|
EXPORT_SYMBOL(icst307_s2div);
|
|
EXPORT_SYMBOL(icst525_s2div);
|
|
|
|
unsigned long icst_hz(const struct icst_params *p, struct icst_vco vco)
|
|
{
|
|
u64 dividend = p->ref * 2 * (u64)(vco.v + 8);
|
|
u32 divisor = (vco.r + 2) * p->s2div[vco.s];
|
|
|
|
do_div(dividend, divisor);
|
|
return (unsigned long)dividend;
|
|
}
|
|
|
|
EXPORT_SYMBOL(icst_hz);
|
|
|
|
/*
|
|
* Ascending divisor S values.
|
|
*/
|
|
const unsigned char icst307_idx2s[8] = { 1, 6, 3, 4, 7, 5, 2, 0 };
|
|
const unsigned char icst525_idx2s[8] = { 1, 3, 4, 7, 5, 2, 6, 0 };
|
|
EXPORT_SYMBOL(icst307_idx2s);
|
|
EXPORT_SYMBOL(icst525_idx2s);
|
|
|
|
struct icst_vco
|
|
icst_hz_to_vco(const struct icst_params *p, unsigned long freq)
|
|
{
|
|
struct icst_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max };
|
|
unsigned long f;
|
|
unsigned int i = 0, rd, best = (unsigned int)-1;
|
|
|
|
/*
|
|
* First, find the PLL output divisor such
|
|
* that the PLL output is within spec.
|
|
*/
|
|
do {
|
|
f = freq * p->s2div[p->idx2s[i]];
|
|
|
|
if (f > p->vco_min && f <= p->vco_max)
|
|
break;
|
|
i++;
|
|
} while (i < 8);
|
|
|
|
if (i >= 8)
|
|
return vco;
|
|
|
|
vco.s = p->idx2s[i];
|
|
|
|
/*
|
|
* Now find the closest divisor combination
|
|
* which gives a PLL output of 'f'.
|
|
*/
|
|
for (rd = p->rd_min; rd <= p->rd_max; rd++) {
|
|
unsigned long fref_div, f_pll;
|
|
unsigned int vd;
|
|
int f_diff;
|
|
|
|
fref_div = (2 * p->ref) / rd;
|
|
|
|
vd = (f + fref_div / 2) / fref_div;
|
|
if (vd < p->vd_min || vd > p->vd_max)
|
|
continue;
|
|
|
|
f_pll = fref_div * vd;
|
|
f_diff = f_pll - f;
|
|
if (f_diff < 0)
|
|
f_diff = -f_diff;
|
|
|
|
if ((unsigned)f_diff < best) {
|
|
vco.v = vd - 8;
|
|
vco.r = rd - 2;
|
|
if (f_diff == 0)
|
|
break;
|
|
best = f_diff;
|
|
}
|
|
}
|
|
|
|
return vco;
|
|
}
|
|
|
|
EXPORT_SYMBOL(icst_hz_to_vco);
|