mirror of https://gitee.com/openkylin/linux.git
99 lines
1.9 KiB
C
99 lines
1.9 KiB
C
// 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);
|