rtc: Add Sun4V hypervisor RTC driver.

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

3 files changed, 161 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 5d600ff8d2dd..23403fae45a7 100644
--- a/drivers/rtc/Kconfig
+++ b/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
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index fed42c2f82fb..6850b04a9dd8 100644
--- a/drivers/rtc/Makefile
+++ b/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
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);