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gerrit-public.fairphone.software / kernel / msm-4.9 / 7a138ede551c5282c1b81d191bdd4aa989b119a8 / . / drivers / rtc / rtc-sun4v.c
blob: 2012ccbb4a539dbfaab57ac83558f4a8f712f021 [file] [log] [blame]
David S. Miller7a138ed2008-08-29 01:32:43 -0700[diff] [blame^]1/* rtc-sun4c.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/time.h>
11#include <linux/rtc.h>
12#include <linux/platform_device.h>
13
14#include <asm/hypervisor.h>
15
16MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
17MODULE_DESCRIPTION("SUN4V RTC driver");
18MODULE_LICENSE("GPL");
19
20struct sun4v_rtc {
21 struct rtc_device *rtc;
22 spinlock_t lock;
23};
24
25static unsigned long hypervisor_get_time(void)
26{
27 unsigned long ret, time;
28 int retries = 10000;
29
30retry:
31 ret = sun4v_tod_get(&time);
32 if (ret == HV_EOK)
33 return time;
34 if (ret == HV_EWOULDBLOCK) {
35 if (--retries > 0) {
36 udelay(100);
37 goto retry;
38 }
39 printk(KERN_WARNING "SUN4V: tod_get() timed out.\n");
40 return 0;
41 }
42 printk(KERN_WARNING "SUN4V: tod_get() not supported.\n");
43 return 0;
44}
45
46static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
47{
48 struct sun4v_rtc *p = dev_get_drvdata(dev);
49 unsigned long flags, secs;
50
51 spin_lock_irqsave(&p->lock, flags);
52 secs = hypervisor_get_time();
53 spin_unlock_irqrestore(&p->lock, flags);
54
55 rtc_time_to_tm(secs, tm);
56
57 return 0;
58}
59
60static int hypervisor_set_time(unsigned long secs)
61{
62 unsigned long ret;
63 int retries = 10000;
64
65retry:
66 ret = sun4v_tod_set(secs);
67 if (ret == HV_EOK)
68 return 0;
69 if (ret == HV_EWOULDBLOCK) {
70 if (--retries > 0) {
71 udelay(100);
72 goto retry;
73 }
74 printk(KERN_WARNING "SUN4V: tod_set() timed out.\n");
75 return -EAGAIN;
76 }
77 printk(KERN_WARNING "SUN4V: tod_set() not supported.\n");
78 return -EOPNOTSUPP;
79}
80
81static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
82{
83 struct sun4v_rtc *p = dev_get_drvdata(dev);
84 unsigned long flags, secs;
85 int err;
86
87 err = rtc_tm_to_time(tm, &secs);
88 if (err)
89 return err;
90
91 spin_lock_irqsave(&p->lock, flags);
92 err = hypervisor_set_time(secs);
93 spin_unlock_irqrestore(&p->lock, flags);
94
95 return err;
96}
97
98static const struct rtc_class_ops sun4v_rtc_ops = {
99 .read_time = sun4v_read_time,
100 .set_time = sun4v_set_time,
101};
102
103static int __devinit sun4v_rtc_probe(struct platform_device *pdev)
104{
105 struct sun4v_rtc *p = kzalloc(sizeof(*p), GFP_KERNEL);
106
107 if (!p)
108 return -ENOMEM;
109
110 spin_lock_init(&p->lock);
111
112 p->rtc = rtc_device_register("sun4v", &pdev->dev,
113 &sun4v_rtc_ops, THIS_MODULE);
114 if (IS_ERR(p->rtc)) {
115 int err = PTR_ERR(p->rtc);
116 kfree(p);
117 return err;
118 }
119 platform_set_drvdata(pdev, p);
120 return 0;
121}
122
123static int __devexit sun4v_rtc_remove(struct platform_device *pdev)
124{
125 struct sun4v_rtc *p = platform_get_drvdata(pdev);
126
127 rtc_device_unregister(p->rtc);
128 kfree(p);
129
130 return 0;
131}
132
133static struct platform_driver sun4v_rtc_driver = {
134 .driver = {
135 .name = "rtc-sun4v",
136 .owner = THIS_MODULE,
137 },
138 .probe = sun4v_rtc_probe,
139 .remove = __devexit_p(sun4v_rtc_remove),
140};
141
142static int __init sun4v_rtc_init(void)
143{
144 return platform_driver_register(&sun4v_rtc_driver);
145}
146
147static void __exit sun4v_rtc_exit(void)
148{
149 platform_driver_unregister(&sun4v_rtc_driver);
150}
151
152module_init(sun4v_rtc_init);
153module_exit(sun4v_rtc_exit);