cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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adau-utils.c (1253B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Shared helper functions for devices from the ADAU family
      4 *
      5 * Copyright 2011-2016 Analog Devices Inc.
      6 * Author: Lars-Peter Clausen <lars@metafoo.de>
      7 */
      8
      9#include <linux/gcd.h>
     10#include <linux/kernel.h>
     11#include <linux/module.h>
     12
     13#include "adau-utils.h"
     14
     15int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out,
     16	uint8_t regs[5])
     17{
     18	unsigned int r, n, m, i, j;
     19	unsigned int div;
     20
     21	if (!freq_out) {
     22		r = 0;
     23		n = 0;
     24		m = 0;
     25		div = 0;
     26	} else {
     27		if (freq_out % freq_in != 0) {
     28			div = DIV_ROUND_UP(freq_in, 13500000);
     29			freq_in /= div;
     30			r = freq_out / freq_in;
     31			i = freq_out % freq_in;
     32			j = gcd(i, freq_in);
     33			n = i / j;
     34			m = freq_in / j;
     35			div--;
     36		} else {
     37			r = freq_out / freq_in;
     38			n = 0;
     39			m = 0;
     40			div = 0;
     41		}
     42		if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2)
     43			return -EINVAL;
     44	}
     45
     46	regs[0] = m >> 8;
     47	regs[1] = m & 0xff;
     48	regs[2] = n >> 8;
     49	regs[3] = n & 0xff;
     50	regs[4] = (r << 3) | (div << 1);
     51	if (m != 0)
     52		regs[4] |= 1; /* Fractional mode */
     53
     54	return 0;
     55}
     56EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);
     57
     58MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
     59MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
     60MODULE_LICENSE("GPL v2");