Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / drivers / rtc / rtc-sun4v.c
1 /* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
2  *
3  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/delay.h>
9 #include <linux/init.h>
10 #include <linux/rtc.h>
11 #include <linux/platform_device.h>
12
13 #include <asm/hypervisor.h>
14
15 static unsigned long hypervisor_get_time(void)
16 {
17         unsigned long ret, time;
18         int retries = 10000;
19
20 retry:
21         ret = sun4v_tod_get(&time);
22         if (ret == HV_EOK)
23                 return time;
24         if (ret == HV_EWOULDBLOCK) {
25                 if (--retries > 0) {
26                         udelay(100);
27                         goto retry;
28                 }
29                 printk(KERN_WARNING "SUN4V: tod_get() timed out.\n");
30                 return 0;
31         }
32         printk(KERN_WARNING "SUN4V: tod_get() not supported.\n");
33         return 0;
34 }
35
36 static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
37 {
38         rtc_time_to_tm(hypervisor_get_time(), tm);
39         return 0;
40 }
41
42 static int hypervisor_set_time(unsigned long secs)
43 {
44         unsigned long ret;
45         int retries = 10000;
46
47 retry:
48         ret = sun4v_tod_set(secs);
49         if (ret == HV_EOK)
50                 return 0;
51         if (ret == HV_EWOULDBLOCK) {
52                 if (--retries > 0) {
53                         udelay(100);
54                         goto retry;
55                 }
56                 printk(KERN_WARNING "SUN4V: tod_set() timed out.\n");
57                 return -EAGAIN;
58         }
59         printk(KERN_WARNING "SUN4V: tod_set() not supported.\n");
60         return -EOPNOTSUPP;
61 }
62
63 static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
64 {
65         unsigned long secs;
66         int err;
67
68         err = rtc_tm_to_time(tm, &secs);
69         if (err)
70                 return err;
71
72         return hypervisor_set_time(secs);
73 }
74
75 static const struct rtc_class_ops sun4v_rtc_ops = {
76         .read_time      = sun4v_read_time,
77         .set_time       = sun4v_set_time,
78 };
79
80 static int __init sun4v_rtc_probe(struct platform_device *pdev)
81 {
82         struct rtc_device *rtc = rtc_device_register("sun4v", &pdev->dev,
83                                      &sun4v_rtc_ops, THIS_MODULE);
84         if (IS_ERR(rtc))
85                 return PTR_ERR(rtc);
86
87         platform_set_drvdata(pdev, rtc);
88         return 0;
89 }
90
91 static int __exit sun4v_rtc_remove(struct platform_device *pdev)
92 {
93         struct rtc_device *rtc = platform_get_drvdata(pdev);
94
95         rtc_device_unregister(rtc);
96         return 0;
97 }
98
99 static struct platform_driver sun4v_rtc_driver = {
100         .driver         = {
101                 .name   = "rtc-sun4v",
102                 .owner  = THIS_MODULE,
103         },
104         .remove         = __exit_p(sun4v_rtc_remove),
105 };
106
107 static int __init sun4v_rtc_init(void)
108 {
109         return platform_driver_probe(&sun4v_rtc_driver, sun4v_rtc_probe);
110 }
111
112 static void __exit sun4v_rtc_exit(void)
113 {
114         platform_driver_unregister(&sun4v_rtc_driver);
115 }
116
117 module_init(sun4v_rtc_init);
118 module_exit(sun4v_rtc_exit);
119
120 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
121 MODULE_DESCRIPTION("SUN4V RTC driver");
122 MODULE_LICENSE("GPL");