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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rtc-meson-vrtc.c (3555B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2019 BayLibre, SAS
      4 * Author: Neil Armstrong <narmstrong@baylibre.com>
      5 * Copyright (C) 2015 Amlogic, Inc. All rights reserved.
      6 */
      7#include <linux/module.h>
      8#include <linux/platform_device.h>
      9#include <linux/rtc.h>
     10#include <linux/io.h>
     11#include <linux/of.h>
     12#include <linux/time64.h>
     13
     14struct meson_vrtc_data {
     15	void __iomem *io_alarm;
     16	struct rtc_device *rtc;
     17	unsigned long alarm_time;
     18	bool enabled;
     19};
     20
     21static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)
     22{
     23	struct timespec64 time;
     24
     25	dev_dbg(dev, "%s\n", __func__);
     26	ktime_get_raw_ts64(&time);
     27	rtc_time64_to_tm(time.tv_sec, tm);
     28
     29	return 0;
     30}
     31
     32static void meson_vrtc_set_wakeup_time(struct meson_vrtc_data *vrtc,
     33				       unsigned long time)
     34{
     35	writel_relaxed(time, vrtc->io_alarm);
     36}
     37
     38static int meson_vrtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
     39{
     40	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
     41
     42	dev_dbg(dev, "%s: alarm->enabled=%d\n", __func__, alarm->enabled);
     43	if (alarm->enabled)
     44		vrtc->alarm_time = rtc_tm_to_time64(&alarm->time);
     45	else
     46		vrtc->alarm_time = 0;
     47
     48	return 0;
     49}
     50
     51static int meson_vrtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
     52{
     53	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
     54
     55	vrtc->enabled = enabled;
     56	return 0;
     57}
     58
     59static const struct rtc_class_ops meson_vrtc_ops = {
     60	.read_time = meson_vrtc_read_time,
     61	.set_alarm = meson_vrtc_set_alarm,
     62	.alarm_irq_enable = meson_vrtc_alarm_irq_enable,
     63};
     64
     65static int meson_vrtc_probe(struct platform_device *pdev)
     66{
     67	struct meson_vrtc_data *vrtc;
     68
     69	vrtc = devm_kzalloc(&pdev->dev, sizeof(*vrtc), GFP_KERNEL);
     70	if (!vrtc)
     71		return -ENOMEM;
     72
     73	vrtc->io_alarm = devm_platform_ioremap_resource(pdev, 0);
     74	if (IS_ERR(vrtc->io_alarm))
     75		return PTR_ERR(vrtc->io_alarm);
     76
     77	device_init_wakeup(&pdev->dev, 1);
     78
     79	platform_set_drvdata(pdev, vrtc);
     80
     81	vrtc->rtc = devm_rtc_allocate_device(&pdev->dev);
     82	if (IS_ERR(vrtc->rtc))
     83		return PTR_ERR(vrtc->rtc);
     84
     85	vrtc->rtc->ops = &meson_vrtc_ops;
     86	return devm_rtc_register_device(vrtc->rtc);
     87}
     88
     89static int __maybe_unused meson_vrtc_suspend(struct device *dev)
     90{
     91	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
     92
     93	dev_dbg(dev, "%s\n", __func__);
     94	if (vrtc->alarm_time) {
     95		unsigned long local_time;
     96		long alarm_secs;
     97		struct timespec64 time;
     98
     99		ktime_get_raw_ts64(&time);
    100		local_time = time.tv_sec;
    101
    102		dev_dbg(dev, "alarm_time = %lus, local_time=%lus\n",
    103			vrtc->alarm_time, local_time);
    104		alarm_secs = vrtc->alarm_time - local_time;
    105		if (alarm_secs > 0) {
    106			meson_vrtc_set_wakeup_time(vrtc, alarm_secs);
    107			dev_dbg(dev, "system will wakeup in %lds.\n",
    108				alarm_secs);
    109		} else {
    110			dev_err(dev, "alarm time already passed: %lds.\n",
    111				alarm_secs);
    112		}
    113	}
    114
    115	return 0;
    116}
    117
    118static int __maybe_unused meson_vrtc_resume(struct device *dev)
    119{
    120	struct meson_vrtc_data *vrtc = dev_get_drvdata(dev);
    121
    122	dev_dbg(dev, "%s\n", __func__);
    123
    124	vrtc->alarm_time = 0;
    125	meson_vrtc_set_wakeup_time(vrtc, 0);
    126	return 0;
    127}
    128
    129static SIMPLE_DEV_PM_OPS(meson_vrtc_pm_ops,
    130			 meson_vrtc_suspend, meson_vrtc_resume);
    131
    132static const struct of_device_id meson_vrtc_dt_match[] = {
    133	{ .compatible = "amlogic,meson-vrtc"},
    134	{},
    135};
    136MODULE_DEVICE_TABLE(of, meson_vrtc_dt_match);
    137
    138static struct platform_driver meson_vrtc_driver = {
    139	.probe = meson_vrtc_probe,
    140	.driver = {
    141		.name = "meson-vrtc",
    142		.of_match_table = meson_vrtc_dt_match,
    143		.pm = &meson_vrtc_pm_ops,
    144	},
    145};
    146
    147module_platform_driver(meson_vrtc_driver);
    148
    149MODULE_DESCRIPTION("Amlogic Virtual Wakeup RTC Timer driver");
    150MODULE_LICENSE("GPL");