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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st-poweroff.c (2652B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (C) 2014 STMicroelectronics
      4 *
      5 * Power off Restart driver, used in STMicroelectronics devices.
      6 *
      7 * Author: Christophe Kerello <christophe.kerello@st.com>
      8 */
      9
     10#include <linux/module.h>
     11#include <linux/of.h>
     12#include <linux/of_platform.h>
     13#include <linux/platform_device.h>
     14#include <linux/mfd/syscon.h>
     15#include <linux/reboot.h>
     16#include <linux/regmap.h>
     17
     18struct reset_syscfg {
     19	struct regmap *regmap;
     20	/* syscfg used for reset */
     21	unsigned int offset_rst;
     22	unsigned int mask_rst;
     23	/* syscfg used for unmask the reset */
     24	unsigned int offset_rst_msk;
     25	unsigned int mask_rst_msk;
     26};
     27
     28/* STiH407 */
     29#define STIH407_SYSCFG_4000	0x0
     30#define STIH407_SYSCFG_4008	0x20
     31
     32static struct reset_syscfg stih407_reset = {
     33	.offset_rst = STIH407_SYSCFG_4000,
     34	.mask_rst = BIT(0),
     35	.offset_rst_msk = STIH407_SYSCFG_4008,
     36	.mask_rst_msk = BIT(0)
     37};
     38
     39
     40static struct reset_syscfg *st_restart_syscfg;
     41
     42static int st_restart(struct notifier_block *this, unsigned long mode,
     43		      void *cmd)
     44{
     45	/* reset syscfg updated */
     46	regmap_update_bits(st_restart_syscfg->regmap,
     47			   st_restart_syscfg->offset_rst,
     48			   st_restart_syscfg->mask_rst,
     49			   0);
     50
     51	/* unmask the reset */
     52	regmap_update_bits(st_restart_syscfg->regmap,
     53			   st_restart_syscfg->offset_rst_msk,
     54			   st_restart_syscfg->mask_rst_msk,
     55			   0);
     56
     57	return NOTIFY_DONE;
     58}
     59
     60static struct notifier_block st_restart_nb = {
     61	.notifier_call = st_restart,
     62	.priority = 192,
     63};
     64
     65static const struct of_device_id st_reset_of_match[] = {
     66	{
     67		.compatible = "st,stih407-restart",
     68		.data = (void *)&stih407_reset,
     69	},
     70	{}
     71};
     72
     73static int st_reset_probe(struct platform_device *pdev)
     74{
     75	struct device_node *np = pdev->dev.of_node;
     76	const struct of_device_id *match;
     77	struct device *dev = &pdev->dev;
     78
     79	match = of_match_device(st_reset_of_match, dev);
     80	if (!match)
     81		return -ENODEV;
     82
     83	st_restart_syscfg = (struct reset_syscfg *)match->data;
     84
     85	st_restart_syscfg->regmap =
     86		syscon_regmap_lookup_by_phandle(np, "st,syscfg");
     87	if (IS_ERR(st_restart_syscfg->regmap)) {
     88		dev_err(dev, "No syscfg phandle specified\n");
     89		return PTR_ERR(st_restart_syscfg->regmap);
     90	}
     91
     92	return register_restart_handler(&st_restart_nb);
     93}
     94
     95static struct platform_driver st_reset_driver = {
     96	.probe = st_reset_probe,
     97	.driver = {
     98		.name = "st_reset",
     99		.of_match_table = st_reset_of_match,
    100	},
    101};
    102
    103static int __init st_reset_init(void)
    104{
    105	return platform_driver_register(&st_reset_driver);
    106}
    107
    108device_initcall(st_reset_init);
    109
    110MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
    111MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
    112MODULE_LICENSE("GPL v2");