cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

rtc-sun4v.c (1976B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
      3 *
      4 * Author: David S. Miller
      5 *
      6 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
      7 */
      8
      9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
     10
     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);