From 7ca1d488ffe4817adaba61cc05b972782f7d3f91 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 8 May 2007 00:33:42 -0700 Subject: [PATCH] rtc: suspend()/resume() restores system clock RTC class suspend/resume support, re-initializing the system clock on resume from the clock used to initialize it at boot time. - The reinit-on-resume is hooked to the existing RTC_HCTOSYS config option, on the grounds that a clock good enough for init must also be good enough for re-init. - Inlining a version of the code used by ARM, to save and restore the delta between a selected RTC and the current system wall-clock time. - Removes calls to that ARM code from AT91, OMAP1, and S3C RTCs. This means that systems using those RTCs across suspend/resume will likely want to change their kernel configs to enable RTC_HCTOSYS. If HCTOSYS isn't using a second RTC (with battery?), this changes the system's initial date from Jan 1970 to the epoch this hardware uses: 1998 for AT91, 2000 for OMAP1 (assuming no split power mode), etc. This goes on top of the patch series removing "struct class_device" usage from the RTC framework. That's all needed for class suspend()/resume(). Signed-off-by: David Brownell Acked-by: Greg Kroah-Hartman Acked-By: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/Kconfig | 24 ++++++++---- drivers/rtc/class.c | 74 ++++++++++++++++++++++++++++++++++++ drivers/rtc/rtc-at91rm9200.c | 30 --------------- drivers/rtc/rtc-omap.c | 17 --------- drivers/rtc/rtc-s3c.c | 22 ----------- 5 files changed, 91 insertions(+), 76 deletions(-) diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index ec33ee8773..a53ef4d670 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -21,21 +21,31 @@ config RTC_CLASS will be called rtc-class. config RTC_HCTOSYS - bool "Set system time from RTC on startup" + bool "Set system time from RTC on startup and resume" depends on RTC_CLASS = y default y help - If you say yes here, the system time will be set using - the value read from the specified RTC device. This is useful - in order to avoid unnecessary fsck runs. + 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 + unnecessary fsck runs at boot time, and to network better. config RTC_HCTOSYS_DEVICE - string "The RTC to read the time from" + string "RTC used to set the system time" depends on RTC_HCTOSYS = y default "rtc0" help - The RTC device that will be used as the source for - the system time, usually rtc0. + The RTC device that will be used to (re)initialize the system + clock, usually rtc0. Initialization is done when the system + starts up, and when it resumes from a low power state. + + This clock should be battery-backed, so that it reads the correct + time when the system boots from a power-off state. Otherwise, your + system will need an external clock source (like an NTP server). + + If the clock you specify here is not battery backed, it may still + be useful to reinitialize system time when resuming from system + sleep states. Do not specify an RTC here unless it stays powered + during all this system's supported sleep states. config RTC_DEBUG bool "RTC debug support" diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index d58d74cf57..587d251be4 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -32,6 +32,78 @@ static void rtc_device_release(struct device *dev) kfree(rtc); } +#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE) + +/* + * On suspend(), measure the delta between one RTC and the + * system's wall clock; restore it on resume(). + */ + +static struct timespec delta; +static time_t oldtime; + +static int rtc_suspend(struct device *dev, pm_message_t mesg) +{ + struct rtc_device *rtc = to_rtc_device(dev); + struct rtc_time tm; + + if (strncmp(rtc->dev.bus_id, + CONFIG_RTC_HCTOSYS_DEVICE, + BUS_ID_SIZE) != 0) + return 0; + + rtc_read_time(rtc, &tm); + rtc_tm_to_time(&tm, &oldtime); + + /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */ + set_normalized_timespec(&delta, + xtime.tv_sec - oldtime, + xtime.tv_nsec - (NSEC_PER_SEC >> 1)); + + return 0; +} + +static int rtc_resume(struct device *dev) +{ + struct rtc_device *rtc = to_rtc_device(dev); + struct rtc_time tm; + time_t newtime; + struct timespec time; + + if (strncmp(rtc->dev.bus_id, + CONFIG_RTC_HCTOSYS_DEVICE, + BUS_ID_SIZE) != 0) + return 0; + + rtc_read_time(rtc, &tm); + if (rtc_valid_tm(&tm) != 0) { + pr_debug("%s: bogus resume time\n", rtc->dev.bus_id); + return 0; + } + rtc_tm_to_time(&tm, &newtime); + if (newtime <= oldtime) { + if (newtime < oldtime) + pr_debug("%s: time travel!\n", rtc->dev.bus_id); + return 0; + } + + /* restore wall clock using delta against this RTC; + * adjust again for avg 1/2 second RTC sampling error + */ + set_normalized_timespec(&time, + newtime + delta.tv_sec, + (NSEC_PER_SEC >> 1) + delta.tv_nsec); + do_settimeofday(&time); + + return 0; +} + +#else +#define rtc_suspend NULL +#define rtc_resume NULL +#endif + + /** * rtc_device_register - register w/ RTC class * @dev: the device to register @@ -143,6 +215,8 @@ static int __init rtc_init(void) printk(KERN_ERR "%s: couldn't create class\n", __FILE__); return PTR_ERR(rtc_class); } + rtc_class->suspend = rtc_suspend; + rtc_class->resume = rtc_resume; rtc_dev_init(); rtc_sysfs_init(rtc_class); return 0; diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c index 2f06b5f9fb..33795e5a55 100644 --- a/drivers/rtc/rtc-at91rm9200.c +++ b/drivers/rtc/rtc-at91rm9200.c @@ -348,21 +348,10 @@ static int __exit at91_rtc_remove(struct platform_device *pdev) /* AT91RM9200 RTC Power management control */ -static struct timespec at91_rtc_delta; static u32 at91_rtc_imr; static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state) { - struct rtc_time tm; - struct timespec time; - - time.tv_nsec = 0; - - /* calculate time delta for suspend */ - at91_rtc_readtime(&pdev->dev, &tm); - rtc_tm_to_time(&tm, &time.tv_sec); - save_time_delta(&at91_rtc_delta, &time); - /* this IRQ is shared with DBGU and other hardware which isn't * necessarily doing PM like we are... */ @@ -374,36 +363,17 @@ static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state) else at91_sys_write(AT91_RTC_IDR, at91_rtc_imr); } - - pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__, - 1900 + tm.tm_year, tm.tm_mon, tm.tm_mday, - tm.tm_hour, tm.tm_min, tm.tm_sec); - return 0; } static int at91_rtc_resume(struct platform_device *pdev) { - struct rtc_time tm; - struct timespec time; - - time.tv_nsec = 0; - - at91_rtc_readtime(&pdev->dev, &tm); - rtc_tm_to_time(&tm, &time.tv_sec); - restore_time_delta(&at91_rtc_delta, &time); - if (at91_rtc_imr) { if (device_may_wakeup(&pdev->dev)) disable_irq_wake(AT91_ID_SYS); else at91_sys_write(AT91_RTC_IER, at91_rtc_imr); } - - pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__, - 1900 + tm.tm_year, tm.tm_mon, tm.tm_mday, - tm.tm_hour, tm.tm_min, tm.tm_sec); - return 0; } #else diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c index ded35fd13b..e6c7b0149f 100644 --- a/drivers/rtc/rtc-omap.c +++ b/drivers/rtc/rtc-omap.c @@ -488,19 +488,10 @@ static int __devexit omap_rtc_remove(struct platform_device *pdev) #ifdef CONFIG_PM -static struct timespec rtc_delta; static u8 irqstat; static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state) { - struct rtc_time rtc_tm; - struct timespec time; - - time.tv_nsec = 0; - omap_rtc_read_time(NULL, &rtc_tm); - rtc_tm_to_time(&rtc_tm, &time.tv_sec); - - save_time_delta(&rtc_delta, &time); irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG); /* FIXME the RTC alarm is not currently acting as a wakeup event @@ -517,14 +508,6 @@ static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state) static int omap_rtc_resume(struct platform_device *pdev) { - struct rtc_time rtc_tm; - struct timespec time; - - time.tv_nsec = 0; - omap_rtc_read_time(NULL, &rtc_tm); - rtc_tm_to_time(&rtc_tm, &time.tv_sec); - - restore_time_delta(&rtc_delta, &time); if (device_may_wakeup(&pdev->dev)) disable_irq_wake(omap_rtc_alarm); else diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c index 3617c970ca..54b6130534 100644 --- a/drivers/rtc/rtc-s3c.c +++ b/drivers/rtc/rtc-s3c.c @@ -548,37 +548,15 @@ static int ticnt_save; static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state) { - struct rtc_time tm; - struct timespec time; - - time.tv_nsec = 0; - /* save TICNT for anyone using periodic interrupts */ - ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT); - - /* calculate time delta for suspend */ - - s3c_rtc_gettime(&pdev->dev, &tm); - rtc_tm_to_time(&tm, &time.tv_sec); - save_time_delta(&s3c_rtc_delta, &time); s3c_rtc_enable(pdev, 0); - return 0; } static int s3c_rtc_resume(struct platform_device *pdev) { - struct rtc_time tm; - struct timespec time; - - time.tv_nsec = 0; - s3c_rtc_enable(pdev, 1); - s3c_rtc_gettime(&pdev->dev, &tm); - rtc_tm_to_time(&tm, &time.tv_sec); - restore_time_delta(&s3c_rtc_delta, &time); - writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT); return 0; } -- 2.39.5