1/* rtc-sun4v.c: Hypervisor based RTC for SUN4V systems. 2 * 3 * Copyright (C) 2008 David S. Miller <davem@davemloft.net> 4 */ 5 6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7 8#include <linux/kernel.h> 9#include <linux/module.h> 10#include <linux/delay.h> 11#include <linux/init.h> 12#include <linux/rtc.h> 13#include <linux/platform_device.h> 14 15#include <asm/hypervisor.h> 16 17static unsigned long hypervisor_get_time(void) 18{ 19 unsigned long ret, time; 20 int retries = 10000; 21 22retry: 23 ret = sun4v_tod_get(&time); 24 if (ret == HV_EOK) 25 return time; 26 if (ret == HV_EWOULDBLOCK) { 27 if (--retries > 0) { 28 udelay(100); 29 goto retry; 30 } 31 pr_warn("tod_get() timed out.\n"); 32 return 0; 33 } 34 pr_warn("tod_get() not supported.\n"); 35 return 0; 36} 37 38static int sun4v_read_time(struct device *dev, struct rtc_time *tm) 39{ 40 rtc_time_to_tm(hypervisor_get_time(), tm); 41 return 0; 42} 43 44static int hypervisor_set_time(unsigned long secs) 45{ 46 unsigned long ret; 47 int retries = 10000; 48 49retry: 50 ret = sun4v_tod_set(secs); 51 if (ret == HV_EOK) 52 return 0; 53 if (ret == HV_EWOULDBLOCK) { 54 if (--retries > 0) { 55 udelay(100); 56 goto retry; 57 } 58 pr_warn("tod_set() timed out.\n"); 59 return -EAGAIN; 60 } 61 pr_warn("tod_set() not supported.\n"); 62 return -EOPNOTSUPP; 63} 64 65static int sun4v_set_time(struct device *dev, struct rtc_time *tm) 66{ 67 unsigned long secs; 68 int err; 69 70 err = rtc_tm_to_time(tm, &secs); 71 if (err) 72 return err; 73 74 return hypervisor_set_time(secs); 75} 76 77static const struct rtc_class_ops sun4v_rtc_ops = { 78 .read_time = sun4v_read_time, 79 .set_time = sun4v_set_time, 80}; 81 82static int __init sun4v_rtc_probe(struct platform_device *pdev) 83{ 84 struct rtc_device *rtc; 85 86 rtc = devm_rtc_device_register(&pdev->dev, "sun4v", 87 &sun4v_rtc_ops, THIS_MODULE); 88 if (IS_ERR(rtc)) 89 return PTR_ERR(rtc); 90 91 platform_set_drvdata(pdev, rtc); 92 return 0; 93} 94 95static struct platform_driver sun4v_rtc_driver = { 96 .driver = { 97 .name = "rtc-sun4v", 98 }, 99}; 100 101module_platform_driver_probe(sun4v_rtc_driver, sun4v_rtc_probe); 102 103MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); 104MODULE_DESCRIPTION("SUN4V RTC driver"); 105MODULE_LICENSE("GPL"); 106