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authorAlexander Krutwig <alexander.krutwig@embedded-brains.de>2015-03-19 11:38:14 +0100
committerSebastian Huber <sebastian.huber@embedded-brains.de>2015-05-19 15:14:34 +0200
commit4117cd163977737a5e6633c7117d10aa194304cb (patch)
tree4fa7043428b9c082203951eba88ac6c2137e851c /cpukit/score/include/sys/timetc.h
parentsmptests/smpscheduler03: Restructure (diff)
downloadrtems-4117cd163977737a5e6633c7117d10aa194304cb.tar.bz2
timecounter: Import from FreeBSD
Update #2271.
Diffstat (limited to 'cpukit/score/include/sys/timetc.h')
-rw-r--r--cpukit/score/include/sys/timetc.h89
1 files changed, 89 insertions, 0 deletions
diff --git a/cpukit/score/include/sys/timetc.h b/cpukit/score/include/sys/timetc.h
new file mode 100644
index 0000000000..f553101b71
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+++ b/cpukit/score/include/sys/timetc.h
@@ -0,0 +1,89 @@
+/*-
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ *
+ * $FreeBSD r277406 2015-01-20T03:54:30Z$
+ */
+
+#ifndef _SYS_TIMETC_H_
+#define _SYS_TIMETC_H_
+
+#ifndef _KERNEL
+#error "no user-serviceable parts inside"
+#endif
+
+/*-
+ * `struct timecounter' is the interface between the hardware which implements
+ * a timecounter and the MI code which uses this to keep track of time.
+ *
+ * A timecounter is a binary counter which has two properties:
+ * * it runs at a fixed, known frequency.
+ * * it has sufficient bits to not roll over in less than approximately
+ * max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
+ * for some indeterminate value of delta.)
+ */
+
+struct timecounter;
+typedef u_int timecounter_get_t(struct timecounter *);
+typedef void timecounter_pps_t(struct timecounter *);
+
+struct timecounter {
+ timecounter_get_t *tc_get_timecount;
+ /*
+ * This function reads the counter. It is not required to
+ * mask any unimplemented bits out, as long as they are
+ * constant.
+ */
+ timecounter_pps_t *tc_poll_pps;
+ /*
+ * This function is optional. It will be called whenever the
+ * timecounter is rewound, and is intended to check for PPS
+ * events. Normal hardware does not need it but timecounters
+ * which latch PPS in hardware (like sys/pci/xrpu.c) do.
+ */
+ u_int tc_counter_mask;
+ /* This mask should mask off any unimplemented bits. */
+ uint64_t tc_frequency;
+ /* Frequency of the counter in Hz. */
+ char *tc_name;
+ /* Name of the timecounter. */
+ int tc_quality;
+ /*
+ * Used to determine if this timecounter is better than
+ * another timecounter higher means better. Negative
+ * means "only use at explicit request".
+ */
+ u_int tc_flags;
+#define TC_FLAGS_C2STOP 1 /* Timer dies in C2+. */
+#define TC_FLAGS_SUSPEND_SAFE 2 /*
+ * Timer functional across
+ * suspend/resume.
+ */
+
+ void *tc_priv;
+ /* Pointer to the timecounter's private parts. */
+ struct timecounter *tc_next;
+ /* Pointer to the next timecounter. */
+};
+
+extern struct timecounter *timecounter;
+extern int tc_min_ticktock_freq; /*
+ * Minimal tc_ticktock() call frequency,
+ * required to handle counter wraps.
+ */
+
+u_int64_t tc_getfrequency(void);
+void tc_init(struct timecounter *tc);
+void tc_setclock(struct timespec *ts);
+void tc_ticktock(int cnt);
+void cpu_tick_calibration(void);
+
+#ifdef SYSCTL_DECL
+SYSCTL_DECL(_kern_timecounter);
+#endif
+
+#endif /* !_SYS_TIMETC_H_ */