From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/drivers/rtc/hctosys.c | 70 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 kernel/drivers/rtc/hctosys.c (limited to 'kernel/drivers/rtc/hctosys.c') diff --git a/kernel/drivers/rtc/hctosys.c b/kernel/drivers/rtc/hctosys.c new file mode 100644 index 000000000..e1cfa0681 --- /dev/null +++ b/kernel/drivers/rtc/hctosys.c @@ -0,0 +1,70 @@ +/* + * RTC subsystem, initialize system time on startup + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include + +/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary + * whether it stores the most close value or the value with partial + * seconds truncated. However, it is important that we use it to store + * the truncated value. This is because otherwise it is necessary, + * in an rtc sync function, to read both xtime.tv_sec and + * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read + * of >32bits is not possible. So storing the most close value would + * slow down the sync API. So here we have the truncated value and + * the best guess is to add 0.5s. + */ + +static int __init rtc_hctosys(void) +{ + int err = -ENODEV; + struct rtc_time tm; + struct timespec64 tv64 = { + .tv_nsec = NSEC_PER_SEC >> 1, + }; + struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE); + + if (rtc == NULL) { + pr_info("unable to open rtc device (%s)\n", + CONFIG_RTC_HCTOSYS_DEVICE); + goto err_open; + } + + err = rtc_read_time(rtc, &tm); + if (err) { + dev_err(rtc->dev.parent, + "hctosys: unable to read the hardware clock\n"); + goto err_read; + + } + + tv64.tv_sec = rtc_tm_to_time64(&tm); + + err = do_settimeofday64(&tv64); + + dev_info(rtc->dev.parent, + "setting system clock to " + "%d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n", + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec, + (long long) tv64.tv_sec); + +err_read: + rtc_class_close(rtc); + +err_open: + rtc_hctosys_ret = err; + + return err; +} + +late_initcall(rtc_hctosys); -- cgit 1.2.3-korg