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authorOlof Johansson <olof@lixom.net>2012-09-05 15:35:48 -0700
committerOlof Johansson <olof@lixom.net>2012-09-05 15:35:48 -0700
commit1875962377574b4edb7b164001e3e341c25290d5 (patch)
tree374a5299403ec21e2d9a66a6548ce876a388b589 /include/linux/jiffies.h
parent5cbee140a28c2746449ae31e85738043ae4da927 (diff)
parentc88a79a7789b2909ad1cf69ea2c9142030bbd6f4 (diff)
downloadop-kernel-dev-1875962377574b4edb7b164001e3e341c25290d5.zip
op-kernel-dev-1875962377574b4edb7b164001e3e341c25290d5.tar.gz
Merge branch 'soc-core' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into next/dt
* 'soc-core' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas: ARM: mach-shmobile: Add compilation support for dtbs using 'make dtbs' + sync to 3.6-rc3
Diffstat (limited to 'include/linux/jiffies.h')
-rw-r--r--include/linux/jiffies.h29
1 files changed, 19 insertions, 10 deletions
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 265e2c3..8268054 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -39,9 +39,6 @@
# error Invalid value of HZ.
#endif
-/* LATCH is used in the interval timer and ftape setup. */
-#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
-
/* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can
* improve accuracy by shifting LSH bits, hence calculating:
* (NOM << LSH) / DEN
@@ -54,18 +51,30 @@
#define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \
+ ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN))
-/* HZ is the requested value. ACTHZ is actual HZ ("<< 8" is for accuracy) */
-#define ACTHZ (SH_DIV (CLOCK_TICK_RATE, LATCH, 8))
+#ifdef CLOCK_TICK_RATE
+/* LATCH is used in the interval timer and ftape setup. */
+# define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
+
+/*
+ * HZ is the requested value. However the CLOCK_TICK_RATE may not allow
+ * for exactly HZ. So SHIFTED_HZ is high res HZ ("<< 8" is for accuracy)
+ */
+# define SHIFTED_HZ (SH_DIV(CLOCK_TICK_RATE, LATCH, 8))
+#else
+# define SHIFTED_HZ (HZ << 8)
+#endif
-/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */
-#define TICK_NSEC (SH_DIV (1000000UL * 1000, ACTHZ, 8))
+/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */
+#define TICK_NSEC (SH_DIV(1000000UL * 1000, SHIFTED_HZ, 8))
/* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */
#define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)
-/* TICK_USEC_TO_NSEC is the time between ticks in nsec assuming real ACTHZ and */
-/* a value TUSEC for TICK_USEC (can be set bij adjtimex) */
-#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV (TUSEC * USER_HZ * 1000, ACTHZ, 8))
+/*
+ * TICK_USEC_TO_NSEC is the time between ticks in nsec assuming SHIFTED_HZ and
+ * a value TUSEC for TICK_USEC (can be set bij adjtimex)
+ */
+#define TICK_USEC_TO_NSEC(TUSEC) (SH_DIV(TUSEC * USER_HZ * 1000, SHIFTED_HZ, 8))
/* some arch's have a small-data section that can be accessed register-relative
* but that can only take up to, say, 4-byte variables. jiffies being part of
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