rtc: Add Sun4V hypervisor RTC driver.

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/rtc/Kconfig

@@ -592,4 +592,11 @@ config RTC_DRV_PPC
 	 the RTC. This exposes that functionality through the generic RTC
 	 class.
 
+config RTC_DRV_SUN4V
+	bool "SUN4V Hypervisor RTC"
+	depends on SPARC64
+	help
+	  If you say Y here you will get support for the Hypervisor
+	  based RTC on SUN4V systems.
+
 endif # RTC_CLASS

drivers/rtc/Makefile

@@ -39,6 +39,7 @@ obj-$(CONFIG_RTC_DRV_M41T94)	+= rtc-m41t94.o
 obj-$(CONFIG_RTC_DRV_M48T59)	+= rtc-m48t59.o
 obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
 obj-$(CONFIG_RTC_DRV_BQ4802)	+= rtc-bq4802.o
+obj-$(CONFIG_RTC_DRV_SUN4V)	+= rtc-sun4v.o
 obj-$(CONFIG_RTC_DRV_MAX6900)	+= rtc-max6900.o
 obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o
 obj-$(CONFIG_RTC_DRV_OMAP)	+= rtc-omap.o

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);