// SPDX-License-Identifier: GPL-2.0
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/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
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*
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* Author: David S. Miller
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*
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* Copyright (C) 2008 David S. Miller <davem@davemloft.net>
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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/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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#include <asm/hypervisor.h>
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static unsigned long hypervisor_get_time(void)
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{
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unsigned long ret, time;
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int retries = 10000;
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retry:
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ret = sun4v_tod_get(&time);
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if (ret == HV_EOK)
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return time;
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if (ret == HV_EWOULDBLOCK) {
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if (--retries > 0) {
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udelay(100);
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goto retry;
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}
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pr_warn("tod_get() timed out.\n");
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return 0;
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}
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pr_warn("tod_get() not supported.\n");
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return 0;
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}
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static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
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{
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rtc_time64_to_tm(hypervisor_get_time(), tm);
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return 0;
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}
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static int hypervisor_set_time(unsigned long secs)
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{
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unsigned long ret;
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int retries = 10000;
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retry:
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ret = sun4v_tod_set(secs);
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if (ret == HV_EOK)
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return 0;
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if (ret == HV_EWOULDBLOCK) {
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if (--retries > 0) {
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udelay(100);
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goto retry;
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}
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pr_warn("tod_set() timed out.\n");
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return -EAGAIN;
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}
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pr_warn("tod_set() not supported.\n");
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return -EOPNOTSUPP;
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}
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static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
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{
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return hypervisor_set_time(rtc_tm_to_time64(tm));
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}
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static const struct rtc_class_ops sun4v_rtc_ops = {
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.read_time = sun4v_read_time,
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.set_time = sun4v_set_time,
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};
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static int __init sun4v_rtc_probe(struct platform_device *pdev)
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{
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struct rtc_device *rtc;
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rtc = devm_rtc_allocate_device(&pdev->dev);
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if (IS_ERR(rtc))
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return PTR_ERR(rtc);
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rtc->ops = &sun4v_rtc_ops;
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rtc->range_max = U64_MAX;
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platform_set_drvdata(pdev, rtc);
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return rtc_register_device(rtc);
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}
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static struct platform_driver sun4v_rtc_driver = {
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.driver = {
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.name = "rtc-sun4v",
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},
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};
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builtin_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe);
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