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// 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);
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