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1// SPDX-License-Identifier: GPL-2.02/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.3 *4 * Author: David S. Miller5 *6 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>7 */8 9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt10 11#include <linux/kernel.h>12#include <linux/delay.h>13#include <linux/init.h>14#include <linux/rtc.h>15#include <linux/platform_device.h>16 17#include <asm/hypervisor.h>18 19static unsigned long hypervisor_get_time(void)20{21 unsigned long ret, time;22 int retries = 10000;23 24retry:25 ret = sun4v_tod_get(&time);26 if (ret == HV_EOK)27 return time;28 if (ret == HV_EWOULDBLOCK) {29 if (--retries > 0) {30 udelay(100);31 goto retry;32 }33 pr_warn("tod_get() timed out.\n");34 return 0;35 }36 pr_warn("tod_get() not supported.\n");37 return 0;38}39 40static int sun4v_read_time(struct device *dev, struct rtc_time *tm)41{42 rtc_time64_to_tm(hypervisor_get_time(), tm);43 return 0;44}45 46static int hypervisor_set_time(unsigned long secs)47{48 unsigned long ret;49 int retries = 10000;50 51retry:52 ret = sun4v_tod_set(secs);53 if (ret == HV_EOK)54 return 0;55 if (ret == HV_EWOULDBLOCK) {56 if (--retries > 0) {57 udelay(100);58 goto retry;59 }60 pr_warn("tod_set() timed out.\n");61 return -EAGAIN;62 }63 pr_warn("tod_set() not supported.\n");64 return -EOPNOTSUPP;65}66 67static int sun4v_set_time(struct device *dev, struct rtc_time *tm)68{69 return hypervisor_set_time(rtc_tm_to_time64(tm));70}71 72static const struct rtc_class_ops sun4v_rtc_ops = {73 .read_time = sun4v_read_time,74 .set_time = sun4v_set_time,75};76 77static int __init sun4v_rtc_probe(struct platform_device *pdev)78{79 struct rtc_device *rtc;80 81 rtc = devm_rtc_allocate_device(&pdev->dev);82 if (IS_ERR(rtc))83 return PTR_ERR(rtc);84 85 rtc->ops = &sun4v_rtc_ops;86 rtc->range_max = U64_MAX;87 platform_set_drvdata(pdev, rtc);88 89 return devm_rtc_register_device(rtc);90}91 92static struct platform_driver sun4v_rtc_driver = {93 .driver = {94 .name = "rtc-sun4v",95 },96};97 98builtin_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe);99