78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* rtc-sw64-virt.c: Hypervisor based RTC for SW64 systems.
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*
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* Copyright (C) 2021 Lu Feifei <luff@gmail.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/rtc.h>
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#include <linux/platform_device.h>
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#define RTC_IO_ADDR (0x804910000000ULL)
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unsigned long vtime_old, vtime_new;
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static int sw64_virt_read_time(struct device *dev, struct rtc_time *tm)
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{
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unsigned long *ioaddr;
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unsigned long vtime_now;
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long vtime_offset;
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ioaddr = ioremap(RTC_IO_ADDR, sizeof(long));
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if (!vtime_new) {
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rtc_time64_to_tm(*ioaddr, tm);
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} else {
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vtime_now = *ioaddr;
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vtime_offset = vtime_new - vtime_old;
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vtime_now += vtime_offset;
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rtc_time64_to_tm(vtime_now, tm);
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}
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return 0;
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}
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static int sw64_virt_set_time(struct device *dev, struct rtc_time *tm)
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{
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unsigned long *ioaddr;
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ioaddr = ioremap(RTC_IO_ADDR, sizeof(long));
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vtime_old = *ioaddr;
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vtime_new = rtc_tm_to_time64(tm);
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return 0;
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}
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static const struct rtc_class_ops rtc_sw64_virt_ops = {
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.read_time = sw64_virt_read_time,
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.set_time = sw64_virt_set_time,
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};
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static int __init rtc_sw64_virt_probe(struct platform_device *pdev)
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{
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struct rtc_device *rtc;
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rtc = devm_rtc_device_register(&pdev->dev, "sw64_virt",
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&rtc_sw64_virt_ops, THIS_MODULE);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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platform_set_drvdata(pdev, rtc);
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return 0;
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}
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static struct platform_driver rtc_sw64_virt_driver = {
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.driver = {
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.name = "rtc_sw64_virt",
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},
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};
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module_platform_driver_probe(rtc_sw64_virt_driver, rtc_sw64_virt_probe);
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MODULE_AUTHOR("Lu Feifei <luff@gmail.com>");
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MODULE_DESCRIPTION("Sunway virtual RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:rtc_sw64_virt");
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