/* rtc-sun4c.c: Hypervisor based RTC for SUN4V systems.
*
* Copyright (C) 2008 David S. Miller <davem@davemloft.net>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <asm/hypervisor.h>
MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
MODULE_DESCRIPTION("SUN4V RTC driver");
MODULE_LICENSE("GPL");
struct sun4v_rtc {
struct rtc_device *rtc;
spinlock_t lock;
};
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;
}
printk(KERN_WARNING "SUN4V: tod_get() timed out.\n");
return 0;
}
printk(KERN_WARNING "SUN4V: tod_get() not supported.\n");
return 0;
}
static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
{
struct sun4v_rtc *p = dev_get_drvdata(dev);
unsigned long flags, secs;
spin_lock_irqsave(&p->lock, flags);
secs = hypervisor_get_time();
spin_unlock_irqrestore(&p->lock, flags);
rtc_time_to_tm(secs, 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;
}
printk(KERN_WARNING "SUN4V: tod_set() timed out.\n");
return -EAGAIN;
}
printk(KERN_WARNING "SUN4V: tod_set() not supported.\n");
return -EOPNOTSUPP;
}
static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
{
struct sun4v_rtc *p = dev_get_drvdata(dev);
unsigned long flags, secs;
int err;
err = rtc_tm_to_time(tm, &secs);
if (err)
return err;
spin_lock_irqsave(&p->lock, flags);
err = hypervisor_set_time(secs);
spin_unlock_irqrestore(&p->lock, flags);
return err;
}
static const struct rtc_class_ops sun4v_rtc_ops = {
.read_time = sun4v_read_time,
.set_time = sun4v_set_time,
};
static int __devinit sun4v_rtc_probe(struct platform_device *pdev)
{
struct sun4v_rtc *p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
spin_lock_init(&p->lock);
p->rtc = rtc_device_register("sun4v", &pdev->dev,
&sun4v_rtc_ops, THIS_MODULE);
if (IS_ERR(p->rtc)) {
int err = PTR_ERR(p->rtc);
kfree(p);
return err;
}
platform_set_drvdata(pdev, p);
return 0;
}
static int __devexit sun4v_rtc_remove(struct platform_device *pdev)
{
struct sun4v_rtc *p = platform_get_drvdata(pdev);
rtc_device_unregister(p->rtc);
kfree(p);
return 0;
}
static struct platform_driver sun4v_rtc_driver = {
.driver = {
.name = "rtc-sun4v",
.owner = THIS_MODULE,
},
.probe = sun4v_rtc_probe,
.remove = __devexit_p(sun4v_rtc_remove),
};
static int __init sun4v_rtc_init(void)
{
return platform_driver_register(&sun4v_rtc_driver);
}
static void __exit sun4v_rtc_exit(void)
{
platform_driver_unregister(&sun4v_rtc_driver);
}
module_init(sun4v_rtc_init);
module_exit(sun4v_rtc_exit);
