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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/blackfin/include/asm/time.h
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/blackfin/include/asm/time.h')
-rw-r--r--kernel/arch/blackfin/include/asm/time.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/arch/blackfin/include/asm/time.h b/kernel/arch/blackfin/include/asm/time.h
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--- /dev/null
+++ b/kernel/arch/blackfin/include/asm/time.h
@@ -0,0 +1,46 @@
+/*
+ * asm-blackfin/time.h:
+ *
+ * Copyright 2004-2008 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef _ASM_BLACKFIN_TIME_H
+#define _ASM_BLACKFIN_TIME_H
+
+/*
+ * The way that the Blackfin core timer works is:
+ * - CCLK is divided by a programmable 8-bit pre-scaler (TSCALE)
+ * - Every time TSCALE ticks, a 32bit is counted down (TCOUNT)
+ *
+ * If you take the fastest clock (1ns, or 1GHz to make the math work easier)
+ * 10ms is 10,000,000 clock ticks, which fits easy into a 32-bit counter
+ * (32 bit counter is 4,294,967,296ns or 4.2 seconds) so, we don't need
+ * to use TSCALE, and program it to zero (which is pass CCLK through).
+ * If you feel like using it, try to keep HZ * TIMESCALE to some
+ * value that divides easy (like power of 2).
+ */
+
+#ifndef CONFIG_CPU_FREQ
+# define TIME_SCALE 1
+#else
+/*
+ * Blackfin CPU frequency scaling supports max Core Clock 1, 1/2 and 1/4 .
+ * Whenever we change the Core Clock frequency changes we immediately
+ * adjust the Core Timer Presale Register. This way we don't lose time.
+ */
+#define TIME_SCALE 4
+
+# ifdef CONFIG_CYCLES_CLOCKSOURCE
+extern unsigned long long __bfin_cycles_off;
+extern unsigned int __bfin_cycles_mod;
+# endif
+#endif
+
+#if defined(CONFIG_TICKSOURCE_CORETMR)
+extern void bfin_coretmr_init(void);
+extern void bfin_coretmr_clockevent_init(void);
+#endif
+
+#endif