cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

mach-osiris-dvs.c (3844B)

      1// SPDX-License-Identifier: GPL-2.0
      2//
      3// Copyright (c) 2009 Simtec Electronics
      4//	http://armlinux.simtec.co.uk/
      5//	Ben Dooks <ben@simtec.co.uk>
      6//
      7// Simtec Osiris Dynamic Voltage Scaling support.
      8
      9#include <linux/kernel.h>
     10#include <linux/module.h>
     11#include <linux/platform_device.h>
     12#include <linux/cpufreq.h>
     13#include <linux/gpio.h>
     14
     15#include <linux/mfd/tps65010.h>
     16
     17#include <linux/soc/samsung/s3c-cpu-freq.h>
     18#include "gpio-samsung.h"
     19
     20#define OSIRIS_GPIO_DVS	S3C2410_GPB(5)
     21
     22static bool dvs_en;
     23
     24static void osiris_dvs_tps_setdvs(bool on)
     25{
     26	unsigned vregs1 = 0, vdcdc2 = 0;
     27
     28	if (!on) {
     29		vdcdc2 = TPS_VCORE_DISCH | TPS_LP_COREOFF;
     30		vregs1 = TPS_LDO1_OFF;	/* turn off in low-power mode */
     31	}
     32
     33	dvs_en = on;
     34	vdcdc2 |= TPS_VCORE_1_3V | TPS_VCORE_LP_1_0V;
     35	vregs1 |= TPS_LDO2_ENABLE | TPS_LDO1_ENABLE;
     36
     37	tps65010_config_vregs1(vregs1);
     38	tps65010_config_vdcdc2(vdcdc2);
     39}
     40
     41static bool is_dvs(struct s3c_freq *f)
     42{
     43	/* at the moment, we assume ARMCLK = HCLK => DVS */
     44	return f->armclk == f->hclk;
     45}
     46
     47/* keep track of current state */
     48static bool cur_dvs = false;
     49
     50static int osiris_dvs_notify(struct notifier_block *nb,
     51			      unsigned long val, void *data)
     52{
     53	struct cpufreq_freqs *cf = data;
     54	struct s3c_cpufreq_freqs *freqs = to_s3c_cpufreq(cf);
     55	bool old_dvs = is_dvs(&freqs->old);
     56	bool new_dvs = is_dvs(&freqs->new);
     57	int ret = 0;
     58
     59	if (!dvs_en)
     60		return 0;
     61
     62	printk(KERN_DEBUG "%s: old %ld,%ld new %ld,%ld\n", __func__,
     63	       freqs->old.armclk, freqs->old.hclk,
     64	       freqs->new.armclk, freqs->new.hclk);
     65
     66	switch (val) {
     67	case CPUFREQ_PRECHANGE:
     68		if ((old_dvs && !new_dvs) ||
     69		    (cur_dvs && !new_dvs)) {
     70			pr_debug("%s: exiting dvs\n", __func__);
     71			cur_dvs = false;
     72			gpio_set_value(OSIRIS_GPIO_DVS, 1);
     73		}
     74		break;
     75	case CPUFREQ_POSTCHANGE:
     76		if ((!old_dvs && new_dvs) ||
     77		    (!cur_dvs && new_dvs)) {
     78			pr_debug("entering dvs\n");
     79			cur_dvs = true;
     80			gpio_set_value(OSIRIS_GPIO_DVS, 0);
     81		}
     82		break;
     83	}
     84
     85	return ret;
     86}
     87
     88static struct notifier_block osiris_dvs_nb = {
     89	.notifier_call	= osiris_dvs_notify,
     90};
     91
     92static int osiris_dvs_probe(struct platform_device *pdev)
     93{
     94	int ret;
     95
     96	dev_info(&pdev->dev, "initialising\n");
     97
     98	ret = gpio_request(OSIRIS_GPIO_DVS, "osiris-dvs");
     99	if (ret) {
    100		dev_err(&pdev->dev, "cannot claim gpio\n");
    101		goto err_nogpio;
    102	}
    103
    104	/* start with dvs disabled */
    105	gpio_direction_output(OSIRIS_GPIO_DVS, 1);
    106
    107	ret = cpufreq_register_notifier(&osiris_dvs_nb,
    108					CPUFREQ_TRANSITION_NOTIFIER);
    109	if (ret) {
    110		dev_err(&pdev->dev, "failed to register with cpufreq\n");
    111		goto err_nofreq;
    112	}
    113
    114	osiris_dvs_tps_setdvs(true);
    115
    116	return 0;
    117
    118err_nofreq:
    119	gpio_free(OSIRIS_GPIO_DVS);
    120
    121err_nogpio:
    122	return ret;
    123}
    124
    125static int osiris_dvs_remove(struct platform_device *pdev)
    126{
    127	dev_info(&pdev->dev, "exiting\n");
    128
    129	/* disable any current dvs */
    130	gpio_set_value(OSIRIS_GPIO_DVS, 1);
    131	osiris_dvs_tps_setdvs(false);
    132
    133	cpufreq_unregister_notifier(&osiris_dvs_nb,
    134				    CPUFREQ_TRANSITION_NOTIFIER);
    135
    136	gpio_free(OSIRIS_GPIO_DVS);
    137
    138	return 0;
    139}
    140
    141/* the CONFIG_PM block is so small, it isn't worth actually compiling it
    142 * out if the configuration isn't set. */
    143
    144static int osiris_dvs_suspend(struct device *dev)
    145{
    146	gpio_set_value(OSIRIS_GPIO_DVS, 1);
    147	osiris_dvs_tps_setdvs(false);
    148	cur_dvs = false;
    149
    150	return 0;
    151}
    152
    153static int osiris_dvs_resume(struct device *dev)
    154{
    155	osiris_dvs_tps_setdvs(true);
    156	return 0;
    157}
    158
    159static const struct dev_pm_ops osiris_dvs_pm = {
    160	.suspend	= osiris_dvs_suspend,
    161	.resume		= osiris_dvs_resume,
    162};
    163
    164static struct platform_driver osiris_dvs_driver = {
    165	.probe		= osiris_dvs_probe,
    166	.remove		= osiris_dvs_remove,
    167	.driver		= {
    168		.name	= "osiris-dvs",
    169		.pm	= &osiris_dvs_pm,
    170	},
    171};
    172
    173module_platform_driver(osiris_dvs_driver);
    174
    175MODULE_DESCRIPTION("Simtec OSIRIS DVS support");
    176MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
    177MODULE_LICENSE("GPL");
    178MODULE_ALIAS("platform:osiris-dvs");