/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems. * * Author: David S. Miller * License: GPL * * 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_time_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) { unsigned long secs; int err; err = rtc_tm_to_time(tm, &secs); if (err) return err; return hypervisor_set_time(secs); } 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_device_register(&pdev->dev, "sun4v", &sun4v_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(pdev, rtc); return 0; } static struct platform_driver sun4v_rtc_driver = { .driver = { .name = "rtc-sun4v", }, }; builtin_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe);