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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mt6323-poweroff.c (2289B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Power off through MediaTek PMIC
      4 *
      5 * Copyright (C) 2018 MediaTek Inc.
      6 *
      7 * Author: Sean Wang <sean.wang@mediatek.com>
      8 *
      9 */
     10
     11#include <linux/err.h>
     12#include <linux/module.h>
     13#include <linux/of.h>
     14#include <linux/platform_device.h>
     15#include <linux/mfd/mt6397/core.h>
     16#include <linux/mfd/mt6397/rtc.h>
     17
     18struct mt6323_pwrc {
     19	struct device *dev;
     20	struct regmap *regmap;
     21	u32 base;
     22};
     23
     24static struct mt6323_pwrc *mt_pwrc;
     25
     26static void mt6323_do_pwroff(void)
     27{
     28	struct mt6323_pwrc *pwrc = mt_pwrc;
     29	unsigned int val;
     30	int ret;
     31
     32	regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
     33	regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR_MT6323, 1);
     34
     35	ret = regmap_read_poll_timeout(pwrc->regmap,
     36					pwrc->base + RTC_BBPU, val,
     37					!(val & RTC_BBPU_CBUSY),
     38					MTK_RTC_POLL_DELAY_US,
     39					MTK_RTC_POLL_TIMEOUT);
     40	if (ret)
     41		dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);
     42
     43	/* Wait some time until system down, otherwise, notice with a warn */
     44	mdelay(1000);
     45
     46	WARN_ONCE(1, "Unable to power off system\n");
     47}
     48
     49static int mt6323_pwrc_probe(struct platform_device *pdev)
     50{
     51	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
     52	struct mt6323_pwrc *pwrc;
     53	struct resource *res;
     54
     55	pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
     56	if (!pwrc)
     57		return -ENOMEM;
     58
     59	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     60	if (!res)
     61		return -EINVAL;
     62
     63	pwrc->base = res->start;
     64	pwrc->regmap = mt6397_chip->regmap;
     65	pwrc->dev = &pdev->dev;
     66	mt_pwrc = pwrc;
     67
     68	pm_power_off = &mt6323_do_pwroff;
     69
     70	return 0;
     71}
     72
     73static int mt6323_pwrc_remove(struct platform_device *pdev)
     74{
     75	if (pm_power_off == &mt6323_do_pwroff)
     76		pm_power_off = NULL;
     77
     78	return 0;
     79}
     80
     81static const struct of_device_id mt6323_pwrc_dt_match[] = {
     82	{ .compatible = "mediatek,mt6323-pwrc" },
     83	{},
     84};
     85MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);
     86
     87static struct platform_driver mt6323_pwrc_driver = {
     88	.probe          = mt6323_pwrc_probe,
     89	.remove         = mt6323_pwrc_remove,
     90	.driver         = {
     91		.name   = "mt6323-pwrc",
     92		.of_match_table = mt6323_pwrc_dt_match,
     93	},
     94};
     95
     96module_platform_driver(mt6323_pwrc_driver);
     97
     98MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
     99MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
    100MODULE_LICENSE("GPL v2");