From 023f333a99cee9b5cd3268ff87298eb01a31f78e Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 17 Dec 2012 14:30:53 -0700 Subject: NTP: Add a CONFIG_RTC_SYSTOHC configuration The purpose of this option is to allow ARM/etc systems that rely on the class RTC subsystem to have the same kind of automatic NTP based synchronization that we have on PC platforms. Today ARM does not implement update_persistent_clock and makes extensive use of the class RTC system. When enabled CONFIG_RTC_SYSTOHC will provide a generic rtc_update_persistent_clock that stores the current time in the RTC and is intended complement the existing CONFIG_RTC_HCTOSYS option that loads the RTC at boot. Like with RTC_HCTOSYS the platform's update_persistent_clock is used first, if it works. Platforms with mixed class RTC and non-RTC drivers need to return ENODEV when class RTC should be used. Such an update for PPC is included in this patch. Long term, implementations of update_persistent_clock should migrate to proper class RTC drivers and use CONFIG_RTC_SYSTOHC instead. Tested on ARM kirkwood and PPC405 Signed-off-by: Jason Gunthorpe Signed-off-by: John Stultz --- drivers/rtc/Kconfig | 10 +++++++++- drivers/rtc/Makefile | 1 + drivers/rtc/systohc.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+), 1 deletion(-) create mode 100644 drivers/rtc/systohc.c (limited to 'drivers/rtc') diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 19c03ab2bdcb..b377e9672497 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -25,9 +25,17 @@ config RTC_HCTOSYS the value read from a specified RTC device. This is useful to avoid unnecessary fsck runs at boot time, and to network better. +config RTC_SYSTOHC + bool "Set the RTC time based on NTP synchronization" + default y + help + If you say yes here, the system time (wall clock) will be stored + in the RTC specified by RTC_HCTOSYS_DEVICE approximately every 11 + minutes if userspace reports synchronized NTP status. + config RTC_HCTOSYS_DEVICE string "RTC used to set the system time" - depends on RTC_HCTOSYS = y + depends on RTC_HCTOSYS = y || RTC_SYSTOHC = y default "rtc0" help The RTC device that will be used to (re)initialize the system diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 56297f0fd388..69d11f1d76e4 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -6,6 +6,7 @@ ccflags-$(CONFIG_RTC_DEBUG) := -DDEBUG obj-$(CONFIG_RTC_LIB) += rtc-lib.o obj-$(CONFIG_RTC_HCTOSYS) += hctosys.o +obj-$(CONFIG_RTC_SYSTOHC) += systohc.o obj-$(CONFIG_RTC_CLASS) += rtc-core.o rtc-core-y := class.o interface.o diff --git a/drivers/rtc/systohc.c b/drivers/rtc/systohc.c new file mode 100644 index 000000000000..bf3e242ccc5c --- /dev/null +++ b/drivers/rtc/systohc.c @@ -0,0 +1,44 @@ +/* + * 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. + * + */ +#include +#include + +/** + * rtc_set_ntp_time - Save NTP synchronized time to the RTC + * @now: Current time of day + * + * Replacement for the NTP platform function update_persistent_clock + * that stores time for later retrieval by rtc_hctosys. + * + * Returns 0 on successful RTC update, -ENODEV if a RTC update is not + * possible at all, and various other -errno for specific temporary failure + * cases. + * + * If temporary failure is indicated the caller should try again 'soon' + */ +int rtc_set_ntp_time(struct timespec now) +{ + struct rtc_device *rtc; + struct rtc_time tm; + int err = -ENODEV; + + if (now.tv_nsec < (NSEC_PER_SEC >> 1)) + rtc_time_to_tm(now.tv_sec, &tm); + else + rtc_time_to_tm(now.tv_sec + 1, &tm); + + rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE); + if (rtc) { + /* rtc_hctosys exclusively uses UTC, so we call set_time here, + * not set_mmss. */ + if (rtc->ops && (rtc->ops->set_time || rtc->ops->set_mmss)) + err = rtc_set_time(rtc, &tm); + rtc_class_close(rtc); + } + + return err; +} -- cgit v1.2.3-59-g8ed1b From 9ecf37eb7a81e3295a1b274eafb6f83d7d2cabf0 Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 16 Jan 2013 00:09:48 +0800 Subject: rtc: Skip the suspend/resume handling if persistent clock exist MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit All the RTC suspend and resume functions are to compensate the sleep time, but this is already done in timekeeping.c if persistent clock exist. Cc: Thomas Gleixner Cc: John Stultz Cc: Alessandro Zummo Cc: Arve Hjønnevåg Signed-off-by: Feng Tang Signed-off-by: John Stultz --- drivers/rtc/class.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/rtc') diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index f8a0aab218cb..c01773f56435 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -50,6 +50,10 @@ static int rtc_suspend(struct device *dev, pm_message_t mesg) struct rtc_device *rtc = to_rtc_device(dev); struct rtc_time tm; struct timespec delta, delta_delta; + + if (has_persistent_clock()) + return 0; + if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) return 0; @@ -88,6 +92,9 @@ static int rtc_resume(struct device *dev) struct timespec new_system, new_rtc; struct timespec sleep_time; + if (has_persistent_clock()) + return 0; + rtc_hctosys_ret = -ENODEV; if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) return 0; -- cgit v1.2.3-59-g8ed1b From 05ad717c77b1b8e98a1dd768c3700036d634629e Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 16 Jan 2013 00:09:49 +0800 Subject: timekeeping: Add CONFIG_HAS_PERSISTENT_CLOCK option Make the persistent clock check a kernel config option, so that some platform can explicitely select it, also make CONFIG_RTC_HCTOSYS and RTC_SYSTOHC depend on its non-existence, which could prevent the persistent clock and RTC code from doing similar thing twice during system's init/suspend/resume phases. If the CONFIG_HAS_PERSISTENT_CLOCK=n, then no change happens for kernel which still does the persistent clock check in timekeeping_init(). Cc: Thomas Gleixner Suggested-by: John Stultz Signed-off-by: Feng Tang [jstultz: Added dependency for RTC_SYSTOHC as well] Signed-off-by: John Stultz --- drivers/rtc/Kconfig | 2 ++ include/linux/time.h | 5 +++++ kernel/time/Kconfig | 5 +++++ 3 files changed, 12 insertions(+) (limited to 'drivers/rtc') diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index b377e9672497..05761de7929b 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -20,6 +20,7 @@ if RTC_CLASS config RTC_HCTOSYS bool "Set system time from RTC on startup and resume" default y + depends on !HAS_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be set using the value read from a specified RTC device. This is useful to avoid @@ -28,6 +29,7 @@ config RTC_HCTOSYS config RTC_SYSTOHC bool "Set the RTC time based on NTP synchronization" default y + depends on !HAS_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be stored in the RTC specified by RTC_HCTOSYS_DEVICE approximately every 11 diff --git a/include/linux/time.h b/include/linux/time.h index dfbc4e82e8ba..369b6e3b87d8 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -116,10 +116,15 @@ static inline bool timespec_valid_strict(const struct timespec *ts) } extern bool persistent_clock_exist; + +#ifdef CONFIG_HAS_PERSISTENT_CLOCK +#define has_persistent_clock() true +#else static inline bool has_persistent_clock(void) { return persistent_clock_exist; } +#endif extern void read_persistent_clock(struct timespec *ts); extern void read_boot_clock(struct timespec *ts); diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 8601f0db1261..f7e45b9b142b 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -12,6 +12,11 @@ config CLOCKSOURCE_WATCHDOG config ARCH_CLOCKSOURCE_DATA bool +# Platforms has a persistent clock +config HAS_PERSISTENT_CLOCK + bool + default n + # Timekeeping vsyscall support config GENERIC_TIME_VSYSCALL bool -- cgit v1.2.3-59-g8ed1b From 6f16eebe1ff82176339a0439c98ebec9768b0ee2 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 25 Jan 2013 17:08:12 -0800 Subject: timekeeping: Switch HAS_PERSISTENT_CLOCK to ALWAYS_USE_PERSISTENT_CLOCK Jason pointed out the HAS_PERSISTENT_CLOCK name isn't quite accurate for the config, as some systems may have the persistent_clock in some cases, but not always. So change the config name to the more clear ALWAYS_USE_PERSISTENT_CLOCK. Signed-off-by: John Stultz --- arch/x86/Kconfig | 2 +- drivers/rtc/Kconfig | 4 ++-- include/linux/time.h | 2 +- kernel/time/Kconfig | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/rtc') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a4135b5e562e..335da90560e4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -108,7 +108,7 @@ config X86 select GENERIC_STRNLEN_USER select HAVE_RCU_USER_QS if X86_64 select HAVE_IRQ_TIME_ACCOUNTING - select HAS_PERSISTENT_CLOCK + select ALWAYS_USE_PERSISTENT_CLOCK select GENERIC_KERNEL_THREAD select GENERIC_KERNEL_EXECVE select MODULES_USE_ELF_REL if X86_32 diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 05761de7929b..da60de01f732 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -20,7 +20,7 @@ if RTC_CLASS config RTC_HCTOSYS bool "Set system time from RTC on startup and resume" default y - depends on !HAS_PERSISTENT_CLOCK + depends on !ALWAYS_USE_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be set using the value read from a specified RTC device. This is useful to avoid @@ -29,7 +29,7 @@ config RTC_HCTOSYS config RTC_SYSTOHC bool "Set the RTC time based on NTP synchronization" default y - depends on !HAS_PERSISTENT_CLOCK + depends on !ALWAYS_USE_PERSISTENT_CLOCK help If you say yes here, the system time (wall clock) will be stored in the RTC specified by RTC_HCTOSYS_DEVICE approximately every 11 diff --git a/include/linux/time.h b/include/linux/time.h index 369b6e3b87d8..476e1d7b2c37 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -117,7 +117,7 @@ static inline bool timespec_valid_strict(const struct timespec *ts) extern bool persistent_clock_exist; -#ifdef CONFIG_HAS_PERSISTENT_CLOCK +#ifdef ALWAYS_USE_PERSISTENT_CLOCK #define has_persistent_clock() true #else static inline bool has_persistent_clock(void) diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index f7e45b9b142b..0dddb9d09d0b 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -13,7 +13,7 @@ config ARCH_CLOCKSOURCE_DATA bool # Platforms has a persistent clock -config HAS_PERSISTENT_CLOCK +config ALWAYS_USE_PERSISTENT_CLOCK bool default n -- cgit v1.2.3-59-g8ed1b