1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Author: David S. Miller
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include <linux/kernel.h>
12*4882a593Smuzhiyun #include <linux/delay.h>
13*4882a593Smuzhiyun #include <linux/init.h>
14*4882a593Smuzhiyun #include <linux/rtc.h>
15*4882a593Smuzhiyun #include <linux/platform_device.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #include <asm/hypervisor.h>
18*4882a593Smuzhiyun
hypervisor_get_time(void)19*4882a593Smuzhiyun static unsigned long hypervisor_get_time(void)
20*4882a593Smuzhiyun {
21*4882a593Smuzhiyun unsigned long ret, time;
22*4882a593Smuzhiyun int retries = 10000;
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun retry:
25*4882a593Smuzhiyun ret = sun4v_tod_get(&time);
26*4882a593Smuzhiyun if (ret == HV_EOK)
27*4882a593Smuzhiyun return time;
28*4882a593Smuzhiyun if (ret == HV_EWOULDBLOCK) {
29*4882a593Smuzhiyun if (--retries > 0) {
30*4882a593Smuzhiyun udelay(100);
31*4882a593Smuzhiyun goto retry;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun pr_warn("tod_get() timed out.\n");
34*4882a593Smuzhiyun return 0;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun pr_warn("tod_get() not supported.\n");
37*4882a593Smuzhiyun return 0;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
sun4v_read_time(struct device * dev,struct rtc_time * tm)40*4882a593Smuzhiyun static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun rtc_time64_to_tm(hypervisor_get_time(), tm);
43*4882a593Smuzhiyun return 0;
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
hypervisor_set_time(unsigned long secs)46*4882a593Smuzhiyun static int hypervisor_set_time(unsigned long secs)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun unsigned long ret;
49*4882a593Smuzhiyun int retries = 10000;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun retry:
52*4882a593Smuzhiyun ret = sun4v_tod_set(secs);
53*4882a593Smuzhiyun if (ret == HV_EOK)
54*4882a593Smuzhiyun return 0;
55*4882a593Smuzhiyun if (ret == HV_EWOULDBLOCK) {
56*4882a593Smuzhiyun if (--retries > 0) {
57*4882a593Smuzhiyun udelay(100);
58*4882a593Smuzhiyun goto retry;
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun pr_warn("tod_set() timed out.\n");
61*4882a593Smuzhiyun return -EAGAIN;
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun pr_warn("tod_set() not supported.\n");
64*4882a593Smuzhiyun return -EOPNOTSUPP;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
sun4v_set_time(struct device * dev,struct rtc_time * tm)67*4882a593Smuzhiyun static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
68*4882a593Smuzhiyun {
69*4882a593Smuzhiyun return hypervisor_set_time(rtc_tm_to_time64(tm));
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun static const struct rtc_class_ops sun4v_rtc_ops = {
73*4882a593Smuzhiyun .read_time = sun4v_read_time,
74*4882a593Smuzhiyun .set_time = sun4v_set_time,
75*4882a593Smuzhiyun };
76*4882a593Smuzhiyun
sun4v_rtc_probe(struct platform_device * pdev)77*4882a593Smuzhiyun static int __init sun4v_rtc_probe(struct platform_device *pdev)
78*4882a593Smuzhiyun {
79*4882a593Smuzhiyun struct rtc_device *rtc;
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun rtc = devm_rtc_allocate_device(&pdev->dev);
82*4882a593Smuzhiyun if (IS_ERR(rtc))
83*4882a593Smuzhiyun return PTR_ERR(rtc);
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun rtc->ops = &sun4v_rtc_ops;
86*4882a593Smuzhiyun rtc->range_max = U64_MAX;
87*4882a593Smuzhiyun platform_set_drvdata(pdev, rtc);
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun return rtc_register_device(rtc);
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun static struct platform_driver sun4v_rtc_driver = {
93*4882a593Smuzhiyun .driver = {
94*4882a593Smuzhiyun .name = "rtc-sun4v",
95*4882a593Smuzhiyun },
96*4882a593Smuzhiyun };
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun builtin_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe);
99