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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davinci-cpufreq.c (3871B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * CPU frequency scaling for DaVinci
      4 *
      5 * Copyright (C) 2009 Texas Instruments Incorporated - https://www.ti.com/
      6 *
      7 * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
      8 *
      9 *  Copyright (C) 2005 Nokia Corporation
     10 *  Written by Tony Lindgren <tony@atomide.com>
     11 *
     12 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
     13 *
     14 * Copyright (C) 2007-2008 Texas Instruments, Inc.
     15 * Updated to support OMAP3
     16 * Rajendra Nayak <rnayak@ti.com>
     17 */
     18#include <linux/types.h>
     19#include <linux/cpufreq.h>
     20#include <linux/init.h>
     21#include <linux/err.h>
     22#include <linux/clk.h>
     23#include <linux/platform_data/davinci-cpufreq.h>
     24#include <linux/platform_device.h>
     25#include <linux/export.h>
     26
     27struct davinci_cpufreq {
     28	struct device *dev;
     29	struct clk *armclk;
     30	struct clk *asyncclk;
     31	unsigned long asyncrate;
     32};
     33static struct davinci_cpufreq cpufreq;
     34
     35static int davinci_target(struct cpufreq_policy *policy, unsigned int idx)
     36{
     37	struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
     38	struct clk *armclk = cpufreq.armclk;
     39	unsigned int old_freq, new_freq;
     40	int ret = 0;
     41
     42	old_freq = policy->cur;
     43	new_freq = pdata->freq_table[idx].frequency;
     44
     45	/* if moving to higher frequency, up the voltage beforehand */
     46	if (pdata->set_voltage && new_freq > old_freq) {
     47		ret = pdata->set_voltage(idx);
     48		if (ret)
     49			return ret;
     50	}
     51
     52	ret = clk_set_rate(armclk, new_freq * 1000);
     53	if (ret)
     54		return ret;
     55
     56	if (cpufreq.asyncclk) {
     57		ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
     58		if (ret)
     59			return ret;
     60	}
     61
     62	/* if moving to lower freq, lower the voltage after lowering freq */
     63	if (pdata->set_voltage && new_freq < old_freq)
     64		pdata->set_voltage(idx);
     65
     66	return 0;
     67}
     68
     69static int davinci_cpu_init(struct cpufreq_policy *policy)
     70{
     71	int result = 0;
     72	struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
     73	struct cpufreq_frequency_table *freq_table = pdata->freq_table;
     74
     75	if (policy->cpu != 0)
     76		return -EINVAL;
     77
     78	/* Finish platform specific initialization */
     79	if (pdata->init) {
     80		result = pdata->init();
     81		if (result)
     82			return result;
     83	}
     84
     85	policy->clk = cpufreq.armclk;
     86
     87	/*
     88	 * Time measurement across the target() function yields ~1500-1800us
     89	 * time taken with no drivers on notification list.
     90	 * Setting the latency to 2000 us to accommodate addition of drivers
     91	 * to pre/post change notification list.
     92	 */
     93	cpufreq_generic_init(policy, freq_table, 2000 * 1000);
     94	return 0;
     95}
     96
     97static struct cpufreq_driver davinci_driver = {
     98	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
     99	.verify		= cpufreq_generic_frequency_table_verify,
    100	.target_index	= davinci_target,
    101	.get		= cpufreq_generic_get,
    102	.init		= davinci_cpu_init,
    103	.name		= "davinci",
    104	.attr		= cpufreq_generic_attr,
    105};
    106
    107static int __init davinci_cpufreq_probe(struct platform_device *pdev)
    108{
    109	struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
    110	struct clk *asyncclk;
    111
    112	if (!pdata)
    113		return -EINVAL;
    114	if (!pdata->freq_table)
    115		return -EINVAL;
    116
    117	cpufreq.dev = &pdev->dev;
    118
    119	cpufreq.armclk = clk_get(NULL, "arm");
    120	if (IS_ERR(cpufreq.armclk)) {
    121		dev_err(cpufreq.dev, "Unable to get ARM clock\n");
    122		return PTR_ERR(cpufreq.armclk);
    123	}
    124
    125	asyncclk = clk_get(cpufreq.dev, "async");
    126	if (!IS_ERR(asyncclk)) {
    127		cpufreq.asyncclk = asyncclk;
    128		cpufreq.asyncrate = clk_get_rate(asyncclk);
    129	}
    130
    131	return cpufreq_register_driver(&davinci_driver);
    132}
    133
    134static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
    135{
    136	clk_put(cpufreq.armclk);
    137
    138	if (cpufreq.asyncclk)
    139		clk_put(cpufreq.asyncclk);
    140
    141	return cpufreq_unregister_driver(&davinci_driver);
    142}
    143
    144static struct platform_driver davinci_cpufreq_driver = {
    145	.driver = {
    146		.name	 = "cpufreq-davinci",
    147	},
    148	.remove = __exit_p(davinci_cpufreq_remove),
    149};
    150
    151int __init davinci_cpufreq_init(void)
    152{
    153	return platform_driver_probe(&davinci_cpufreq_driver,
    154							davinci_cpufreq_probe);
    155}
    156