tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
2 *
3 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/delay.h>
11#include <linux/init.h>
12#include <linux/rtc.h>
13#include <linux/platform_device.h>
14
15#include <asm/hypervisor.h>
16
17static unsigned long hypervisor_get_time(void)
18{
19 unsigned long ret, time;
20 int retries = 10000;
21
22retry:
23 ret = sun4v_tod_get(&time);
24 if (ret == HV_EOK)
25 return time;
26 if (ret == HV_EWOULDBLOCK) {
27 if (--retries > 0) {
28 udelay(100);
29 goto retry;
30 }
31 pr_warn("tod_get() timed out.\n");
32 return 0;
33 }
34 pr_warn("tod_get() not supported.\n");
35 return 0;
36}
37
38static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
39{
40 rtc_time_to_tm(hypervisor_get_time(), tm);
41 return 0;
42}
43
44static int hypervisor_set_time(unsigned long secs)
45{
46 unsigned long ret;
47 int retries = 10000;
48
49retry:
50 ret = sun4v_tod_set(secs);
51 if (ret == HV_EOK)
52 return 0;
53 if (ret == HV_EWOULDBLOCK) {
54 if (--retries > 0) {
55 udelay(100);
56 goto retry;
57 }
58 pr_warn("tod_set() timed out.\n");
59 return -EAGAIN;
60 }
61 pr_warn("tod_set() not supported.\n");
62 return -EOPNOTSUPP;
63}
64
65static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
66{
67 unsigned long secs;
68 int err;
69
70 err = rtc_tm_to_time(tm, &secs);
71 if (err)
72 return err;
73
74 return hypervisor_set_time(secs);
75}
76
77static const struct rtc_class_ops sun4v_rtc_ops = {
78 .read_time = sun4v_read_time,
79 .set_time = sun4v_set_time,
80};
81
82static int __init sun4v_rtc_probe(struct platform_device *pdev)
83{
84 struct rtc_device *rtc = rtc_device_register("sun4v", &pdev->dev,
85 &sun4v_rtc_ops, THIS_MODULE);
86 if (IS_ERR(rtc))
87 return PTR_ERR(rtc);
88
89 platform_set_drvdata(pdev, rtc);
90 return 0;
91}
92
93static int __exit sun4v_rtc_remove(struct platform_device *pdev)
94{
95 struct rtc_device *rtc = platform_get_drvdata(pdev);
96
97 rtc_device_unregister(rtc);
98 return 0;
99}
100
101static struct platform_driver sun4v_rtc_driver = {
102 .driver = {
103 .name = "rtc-sun4v",
104 .owner = THIS_MODULE,
105 },
106 .remove = __exit_p(sun4v_rtc_remove),
107};
108
109static int __init sun4v_rtc_init(void)
110{
111 return platform_driver_probe(&sun4v_rtc_driver, sun4v_rtc_probe);
112}
113
114static void __exit sun4v_rtc_exit(void)
115{
116 platform_driver_unregister(&sun4v_rtc_driver);
117}
118
119module_init(sun4v_rtc_init);
120module_exit(sun4v_rtc_exit);
121
122MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
123MODULE_DESCRIPTION("SUN4V RTC driver");
124MODULE_LICENSE("GPL");