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-rw-r--r--drivers/rtc/rtc-sun4v.c98
1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sun4v.c b/drivers/rtc/rtc-sun4v.c
new file mode 100644
index 000000000..a86e27de8
--- /dev/null
+++ b/drivers/rtc/rtc-sun4v.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems.
+ *
+ * Author: David S. Miller
+ *
+ * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+
+#include <asm/hypervisor.h>
+
+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;
+ }
+ pr_warn("tod_get() timed out.\n");
+ return 0;
+ }
+ pr_warn("tod_get() not supported.\n");
+ return 0;
+}
+
+static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
+{
+ rtc_time64_to_tm(hypervisor_get_time(), 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;
+ }
+ pr_warn("tod_set() timed out.\n");
+ return -EAGAIN;
+ }
+ pr_warn("tod_set() not supported.\n");
+ return -EOPNOTSUPP;
+}
+
+static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
+{
+ return hypervisor_set_time(rtc_tm_to_time64(tm));
+}
+
+static const struct rtc_class_ops sun4v_rtc_ops = {
+ .read_time = sun4v_read_time,
+ .set_time = sun4v_set_time,
+};
+
+static int __init sun4v_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc;
+
+ rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ rtc->ops = &sun4v_rtc_ops;
+ rtc->range_max = U64_MAX;
+ platform_set_drvdata(pdev, rtc);
+
+ return devm_rtc_register_device(rtc);
+}
+
+static struct platform_driver sun4v_rtc_driver = {
+ .driver = {
+ .name = "rtc-sun4v",
+ },
+};
+
+builtin_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe);