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