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path: root/drivers/rtc/rtc-sun4v.c
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Diffstat (limited to 'drivers/rtc/rtc-sun4v.c')
-rw-r--r--drivers/rtc/rtc-sun4v.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sun4v.c b/drivers/rtc/rtc-sun4v.c
new file mode 100644
index 000000000000..2012ccbb4a53
--- /dev/null
+++ b/drivers/rtc/rtc-sun4v.c
@@ -0,0 +1,153 @@
+/* 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);