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authorZheng Da <zhengda1936@gmail.com>2009-12-06 05:26:23 +0100
committerZheng Da <zhengda1936@gmail.com>2009-12-06 05:26:23 +0100
commit8a6d48c0542876eb3acfc0970c0ab7872db08d5f (patch)
tree496e78bc728317ea779781b92f897d16936ee231 /libdde_linux26/contrib/include/linux/clocksource.h
parentb4bffcfcdf3ab7a55d664e9aa5907f88da503f38 (diff)
check in the original version of dde linux26.
Diffstat (limited to 'libdde_linux26/contrib/include/linux/clocksource.h')
-rw-r--r--libdde_linux26/contrib/include/linux/clocksource.h245
1 files changed, 245 insertions, 0 deletions
diff --git a/libdde_linux26/contrib/include/linux/clocksource.h b/libdde_linux26/contrib/include/linux/clocksource.h
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+/* linux/include/linux/clocksource.h
+ *
+ * This file contains the structure definitions for clocksources.
+ *
+ * If you are not a clocksource, or timekeeping code, you should
+ * not be including this file!
+ */
+#ifndef _LINUX_CLOCKSOURCE_H
+#define _LINUX_CLOCKSOURCE_H
+
+#include <linux/types.h>
+#include <linux/timex.h>
+#include <linux/time.h>
+#include <linux/list.h>
+#include <linux/cache.h>
+#include <linux/timer.h>
+#include <asm/div64.h>
+#include <asm/io.h>
+
+/* clocksource cycle base type */
+typedef u64 cycle_t;
+struct clocksource;
+
+/**
+ * struct clocksource - hardware abstraction for a free running counter
+ * Provides mostly state-free accessors to the underlying hardware.
+ *
+ * @name: ptr to clocksource name
+ * @list: list head for registration
+ * @rating: rating value for selection (higher is better)
+ * To avoid rating inflation the following
+ * list should give you a guide as to how
+ * to assign your clocksource a rating
+ * 1-99: Unfit for real use
+ * Only available for bootup and testing purposes.
+ * 100-199: Base level usability.
+ * Functional for real use, but not desired.
+ * 200-299: Good.
+ * A correct and usable clocksource.
+ * 300-399: Desired.
+ * A reasonably fast and accurate clocksource.
+ * 400-499: Perfect
+ * The ideal clocksource. A must-use where
+ * available.
+ * @read: returns a cycle value
+ * @mask: bitmask for two's complement
+ * subtraction of non 64 bit counters
+ * @mult: cycle to nanosecond multiplier (adjusted by NTP)
+ * @mult_orig: cycle to nanosecond multiplier (unadjusted by NTP)
+ * @shift: cycle to nanosecond divisor (power of two)
+ * @flags: flags describing special properties
+ * @vread: vsyscall based read
+ * @resume: resume function for the clocksource, if necessary
+ * @cycle_interval: Used internally by timekeeping core, please ignore.
+ * @xtime_interval: Used internally by timekeeping core, please ignore.
+ */
+struct clocksource {
+ /*
+ * First part of structure is read mostly
+ */
+ char *name;
+ struct list_head list;
+ int rating;
+ cycle_t (*read)(void);
+ cycle_t mask;
+ u32 mult;
+ u32 mult_orig;
+ u32 shift;
+ unsigned long flags;
+ cycle_t (*vread)(void);
+ void (*resume)(void);
+#ifdef CONFIG_IA64
+ void *fsys_mmio; /* used by fsyscall asm code */
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr))
+#else
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
+#endif
+
+ /* timekeeping specific data, ignore */
+ cycle_t cycle_interval;
+ u64 xtime_interval;
+ u32 raw_interval;
+ /*
+ * Second part is written at each timer interrupt
+ * Keep it in a different cache line to dirty no
+ * more than one cache line.
+ */
+ cycle_t cycle_last ____cacheline_aligned_in_smp;
+ u64 xtime_nsec;
+ s64 error;
+ struct timespec raw_time;
+
+#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
+ /* Watchdog related data, used by the framework */
+ struct list_head wd_list;
+ cycle_t wd_last;
+#endif
+};
+
+extern struct clocksource *clock; /* current clocksource */
+
+/*
+ * Clock source flags bits::
+ */
+#define CLOCK_SOURCE_IS_CONTINUOUS 0x01
+#define CLOCK_SOURCE_MUST_VERIFY 0x02
+
+#define CLOCK_SOURCE_WATCHDOG 0x10
+#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
+
+/* simplify initialization of mask field */
+#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
+
+/**
+ * clocksource_khz2mult - calculates mult from khz and shift
+ * @khz: Clocksource frequency in KHz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a khz counter frequency to a timsource
+ * multiplier, given the clocksource shift value
+ */
+static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
+{
+ /* khz = cyc/(Million ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Million/khz * 2^shift
+ * mult = 1000000 * 2^shift / khz
+ * mult = (1000000<<shift) / khz
+ */
+ u64 tmp = ((u64)1000000) << shift_constant;
+
+ tmp += khz/2; /* round for do_div */
+ do_div(tmp, khz);
+
+ return (u32)tmp;
+}
+
+/**
+ * clocksource_hz2mult - calculates mult from hz and shift
+ * @hz: Clocksource frequency in Hz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a hz counter
+ * frequency to a timsource multiplier, given the
+ * clocksource shift value
+ */
+static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
+{
+ /* hz = cyc/(Billion ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Billion/hz * 2^shift
+ * mult = 1000000000 * 2^shift / hz
+ * mult = (1000000000<<shift) / hz
+ */
+ u64 tmp = ((u64)1000000000) << shift_constant;
+
+ tmp += hz/2; /* round for do_div */
+ do_div(tmp, hz);
+
+ return (u32)tmp;
+}
+
+/**
+ * clocksource_read: - Access the clocksource's current cycle value
+ * @cs: pointer to clocksource being read
+ *
+ * Uses the clocksource to return the current cycle_t value
+ */
+static inline cycle_t clocksource_read(struct clocksource *cs)
+{
+ return cs->read();
+}
+
+/**
+ * cyc2ns - converts clocksource cycles to nanoseconds
+ * @cs: Pointer to clocksource
+ * @cycles: Cycles
+ *
+ * Uses the clocksource and ntp ajdustment to convert cycle_ts to nanoseconds.
+ *
+ * XXX - This could use some mult_lxl_ll() asm optimization
+ */
+static inline s64 cyc2ns(struct clocksource *cs, cycle_t cycles)
+{
+ u64 ret = (u64)cycles;
+ ret = (ret * cs->mult) >> cs->shift;
+ return ret;
+}
+
+/**
+ * clocksource_calculate_interval - Calculates a clocksource interval struct
+ *
+ * @c: Pointer to clocksource.
+ * @length_nsec: Desired interval length in nanoseconds.
+ *
+ * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
+ * pair and interval request.
+ *
+ * Unless you're the timekeeping code, you should not be using this!
+ */
+static inline void clocksource_calculate_interval(struct clocksource *c,
+ unsigned long length_nsec)
+{
+ u64 tmp;
+
+ /* Do the ns -> cycle conversion first, using original mult */
+ tmp = length_nsec;
+ tmp <<= c->shift;
+ tmp += c->mult_orig/2;
+ do_div(tmp, c->mult_orig);
+
+ c->cycle_interval = (cycle_t)tmp;
+ if (c->cycle_interval == 0)
+ c->cycle_interval = 1;
+
+ /* Go back from cycles -> shifted ns, this time use ntp adjused mult */
+ c->xtime_interval = (u64)c->cycle_interval * c->mult;
+ c->raw_interval = ((u64)c->cycle_interval * c->mult_orig) >> c->shift;
+}
+
+
+/* used to install a new clocksource */
+extern int clocksource_register(struct clocksource*);
+extern void clocksource_unregister(struct clocksource*);
+extern void clocksource_touch_watchdog(void);
+extern struct clocksource* clocksource_get_next(void);
+extern void clocksource_change_rating(struct clocksource *cs, int rating);
+extern void clocksource_resume(void);
+
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+extern void update_vsyscall(struct timespec *ts, struct clocksource *c);
+extern void update_vsyscall_tz(void);
+#else
+static inline void update_vsyscall(struct timespec *ts, struct clocksource *c)
+{
+}
+
+static inline void update_vsyscall_tz(void)
+{
+}
+#endif
+
+#endif /* _LINUX_CLOCKSOURCE_H */