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![Thomas Gleixner](/assets/img/avatar_default.png)
Some ARM SoCs have clock event devices which have their frequency modified due to frequency scaling. Provide an interface which allows to reconfigure an active device. After reconfiguration reprogram the current pending event. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: LAK <linux-arm-kernel@lists.infradead.org> Cc: John Stultz <john.stultz@linaro.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Ingo Molnar <mingo@elte.hu> Link: http://lkml.kernel.org/r/%3C20110518210136.437459958%40linutronix.de%3E
166 lines
4.9 KiB
C
166 lines
4.9 KiB
C
/* linux/include/linux/clockchips.h
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*
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* This file contains the structure definitions for clockchips.
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*
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* If you are not a clockchip, or the time of day code, you should
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* not be including this file!
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*/
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#ifndef _LINUX_CLOCKCHIPS_H
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#define _LINUX_CLOCKCHIPS_H
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD
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#include <linux/clocksource.h>
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#include <linux/cpumask.h>
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#include <linux/ktime.h>
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#include <linux/notifier.h>
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struct clock_event_device;
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/* Clock event mode commands */
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enum clock_event_mode {
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CLOCK_EVT_MODE_UNUSED = 0,
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CLOCK_EVT_MODE_SHUTDOWN,
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CLOCK_EVT_MODE_PERIODIC,
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CLOCK_EVT_MODE_ONESHOT,
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CLOCK_EVT_MODE_RESUME,
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};
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/* Clock event notification values */
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enum clock_event_nofitiers {
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CLOCK_EVT_NOTIFY_ADD,
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CLOCK_EVT_NOTIFY_BROADCAST_ON,
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CLOCK_EVT_NOTIFY_BROADCAST_OFF,
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CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
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CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
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CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
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CLOCK_EVT_NOTIFY_SUSPEND,
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CLOCK_EVT_NOTIFY_RESUME,
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CLOCK_EVT_NOTIFY_CPU_DYING,
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CLOCK_EVT_NOTIFY_CPU_DEAD,
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};
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/*
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* Clock event features
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*/
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#define CLOCK_EVT_FEAT_PERIODIC 0x000001
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#define CLOCK_EVT_FEAT_ONESHOT 0x000002
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/*
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* x86(64) specific misfeatures:
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*
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* - Clockevent source stops in C3 State and needs broadcast support.
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* - Local APIC timer is used as a dummy device.
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*/
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#define CLOCK_EVT_FEAT_C3STOP 0x000004
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#define CLOCK_EVT_FEAT_DUMMY 0x000008
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/**
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* struct clock_event_device - clock event device descriptor
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* @event_handler: Assigned by the framework to be called by the low
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* level handler of the event source
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* @set_next_event: set next event function
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* @next_event: local storage for the next event in oneshot mode
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* @max_delta_ns: maximum delta value in ns
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* @min_delta_ns: minimum delta value in ns
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* @mult: nanosecond to cycles multiplier
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* @shift: nanoseconds to cycles divisor (power of two)
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* @mode: operating mode assigned by the management code
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* @features: features
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* @retries: number of forced programming retries
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* @set_mode: set mode function
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* @broadcast: function to broadcast events
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* @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
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* @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
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* @name: ptr to clock event name
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* @rating: variable to rate clock event devices
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* @irq: IRQ number (only for non CPU local devices)
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* @cpumask: cpumask to indicate for which CPUs this device works
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* @list: list head for the management code
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*/
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struct clock_event_device {
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void (*event_handler)(struct clock_event_device *);
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int (*set_next_event)(unsigned long evt,
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struct clock_event_device *);
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ktime_t next_event;
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u64 max_delta_ns;
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u64 min_delta_ns;
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u32 mult;
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u32 shift;
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enum clock_event_mode mode;
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unsigned int features;
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unsigned long retries;
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void (*broadcast)(const struct cpumask *mask);
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void (*set_mode)(enum clock_event_mode mode,
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struct clock_event_device *);
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unsigned long min_delta_ticks;
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unsigned long max_delta_ticks;
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const char *name;
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int rating;
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int irq;
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const struct cpumask *cpumask;
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struct list_head list;
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} ____cacheline_aligned;
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/*
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* Calculate a multiplication factor for scaled math, which is used to convert
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* nanoseconds based values to clock ticks:
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*
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* clock_ticks = (nanoseconds * factor) >> shift.
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*
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* div_sc is the rearranged equation to calculate a factor from a given clock
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* ticks / nanoseconds ratio:
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*
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* factor = (clock_ticks << shift) / nanoseconds
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*/
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static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
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int shift)
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{
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uint64_t tmp = ((uint64_t)ticks) << shift;
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do_div(tmp, nsec);
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return (unsigned long) tmp;
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}
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/* Clock event layer functions */
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extern u64 clockevent_delta2ns(unsigned long latch,
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struct clock_event_device *evt);
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extern void clockevents_register_device(struct clock_event_device *dev);
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extern void clockevents_config_and_register(struct clock_event_device *dev,
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u32 freq, unsigned long min_delta,
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unsigned long max_delta);
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extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
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extern void clockevents_exchange_device(struct clock_event_device *old,
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struct clock_event_device *new);
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extern void clockevents_set_mode(struct clock_event_device *dev,
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enum clock_event_mode mode);
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extern int clockevents_register_notifier(struct notifier_block *nb);
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extern int clockevents_program_event(struct clock_event_device *dev,
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ktime_t expires, ktime_t now);
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extern void clockevents_handle_noop(struct clock_event_device *dev);
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static inline void
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clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
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{
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return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
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freq, minsec);
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}
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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extern void clockevents_notify(unsigned long reason, void *arg);
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#else
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# define clockevents_notify(reason, arg) do { } while (0)
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#endif
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#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
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#define clockevents_notify(reason, arg) do { } while (0)
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#endif
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#endif
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