From f44f7f96a20af16f6f12e1c995576d6becf5f57b Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 21 Feb 2011 22:58:51 -0800 Subject: RTC: Initialize kernel state from RTC Mark Brown pointed out a corner case: that RTC alarms should be allowed to be persistent across reboots if the hardware supported it. The rework of the generic layer to virtualize the RTC alarm virtualized much of the alarm handling, and removed the code used to read the alarm time from the hardware. Mark noted if we want the alarm to be persistent across reboots, we need to re-read the alarm value into the virtualized generic layer at boot up, so that the generic layer properly exposes that value. This patch restores much of the earlier removed rtc_read_alarm code and wires it in so that we set the kernel's alarm value to what we find in the hardware at boot time. NOTE: Not all hardware supports persistent RTC alarm state across system reset. rtc-cmos for example will keep the alarm time, but disables the AIE mode irq. Applications should not expect the RTC alarm to be valid after a system reset. We will preserve what we can, to represent the hardware state at boot, but its not guarenteed. Further, in the future, with multiplexed RTC alarms, the soonest alarm to fire may not be the one set via the /dev/rt ioctls. So an application may set the alarm with RTC_ALM_SET, but after a reset find that RTC_ALM_READ returns an earlier time. Again, we preserve what we can, but applications should not expect the RTC alarm state to persist across a system reset. Big thanks to Mark for pointing out the issue! Thanks also to Marcelo for helping think through the solution. CC: Mark Brown CC: Marcelo Roberto Jimenez CC: Thomas Gleixner CC: Alessandro Zummo CC: rtc-linux@googlegroups.com Reported-by: Mark Brown Signed-off-by: John Stultz --- include/linux/rtc.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 89c3e5182991..db3832d5f280 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -227,6 +227,7 @@ extern void rtc_device_unregister(struct rtc_device *rtc); extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm); extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm); extern int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs); +int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm); extern int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alrm); extern int rtc_set_alarm(struct rtc_device *rtc, -- cgit From 80d4bb515b78f38738f3378fd1be6039063ab040 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 3 Feb 2011 11:34:50 -0800 Subject: RTC: Cleanup rtc_class_ops->irq_set_state With PIE mode interrupts now emulated in generic code via an hrtimer, no one calls rtc_class_ops->irq_set_state(), so this patch removes it along with driver implementations. CC: Thomas Gleixner CC: Alessandro Zummo CC: Marcelo Roberto Jimenez CC: rtc-linux@googlegroups.com Signed-off-by: John Stultz --- include/linux/rtc.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index db3832d5f280..0e2063acc260 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -148,7 +148,6 @@ struct rtc_class_ops { int (*set_alarm)(struct device *, struct rtc_wkalrm *); int (*proc)(struct device *, struct seq_file *); int (*set_mmss)(struct device *, unsigned long secs); - int (*irq_set_state)(struct device *, int enabled); int (*irq_set_freq)(struct device *, int freq); int (*read_callback)(struct device *, int data); int (*alarm_irq_enable)(struct device *, unsigned int enabled); -- cgit From 696160fec162601d06940862b5b3aa4460344c1b Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 3 Feb 2011 12:02:07 -0800 Subject: RTC: Cleanup rtc_class_ops->irq_set_freq() With the generic rtc code now emulating PIE mode irqs via an hrtimer, no one calls the rtc_class_ops->irq_set_freq call. This patch removes the hook and deletes the driver functions if no one else calls them. CC: Thomas Gleixner CC: Alessandro Zummo CC: Marcelo Roberto Jimenez CC: rtc-linux@googlegroups.com Signed-off-by: John Stultz --- include/linux/rtc.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 0e2063acc260..741a51cc4460 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -133,7 +133,6 @@ extern struct class *rtc_class; * The (current) exceptions are mostly filesystem hooks: * - the proc() hook for procfs * - non-ioctl() chardev hooks: open(), release(), read_callback() - * - periodic irq calls: irq_set_state(), irq_set_freq() * * REVISIT those periodic irq calls *do* have ops_lock when they're * issued through ioctl() ... @@ -148,7 +147,6 @@ struct rtc_class_ops { int (*set_alarm)(struct device *, struct rtc_wkalrm *); int (*proc)(struct device *, struct seq_file *); int (*set_mmss)(struct device *, unsigned long secs); - int (*irq_set_freq)(struct device *, int freq); int (*read_callback)(struct device *, int data); int (*alarm_irq_enable)(struct device *, unsigned int enabled); int (*update_irq_enable)(struct device *, unsigned int enabled); -- cgit From 51ba60c5bb3b0f71bee26404ddc22d8e4109e88a Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 3 Feb 2011 12:13:50 -0800 Subject: RTC: Cleanup rtc_class_ops->update_irq_enable() Now that the generic code handles UIE mode irqs via periodic alarm interrupts, no one calls the rtc_class_ops->update_irq_enable() method anymore. This patch removes the driver hooks and implementations of update_irq_enable if no one else is calling it. CC: Thomas Gleixner CC: Alessandro Zummo CC: Marcelo Roberto Jimenez CC: rtc-linux@googlegroups.com Signed-off-by: John Stultz --- include/linux/rtc.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 741a51cc4460..2ca7e8a78060 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -149,7 +149,6 @@ struct rtc_class_ops { int (*set_mmss)(struct device *, unsigned long secs); int (*read_callback)(struct device *, int data); int (*alarm_irq_enable)(struct device *, unsigned int enabled); - int (*update_irq_enable)(struct device *, unsigned int enabled); }; #define RTC_DEVICE_NAME_SIZE 20 -- cgit