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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-01-14 20:07:35 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-05-02 09:35:36 +0100
commitf5fc00826d1e60af0e22cb9f65b933d823a8ed84 (patch)
treebcff2df77e951dbfc0833cda47620ee3c65694ac /arch/arm/plat-versatile
parent6be4826e37122b25cb10b215fc84c3a0b1fe1402 (diff)
ARM: Realview/Versatile: separate out common sched_clock()
Provide a common sched_clock() implementation for Versatile and Realview. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-versatile')
-rw-r--r--arch/arm/plat-versatile/Makefile2
-rw-r--r--arch/arm/plat-versatile/sched-clock.c53
2 files changed, 55 insertions, 0 deletions
diff --git a/arch/arm/plat-versatile/Makefile b/arch/arm/plat-versatile/Makefile
index 334d2f14232..9b1a66816aa 100644
--- a/arch/arm/plat-versatile/Makefile
+++ b/arch/arm/plat-versatile/Makefile
@@ -1,2 +1,4 @@
obj-y := clock.o
obj-$(CONFIG_ARM_TIMER_SP804) += timer-sp.o
+obj-$(CONFIG_ARCH_REALVIEW) += sched-clock.o
+obj-$(CONFIG_ARCH_VERSATILE) += sched-clock.o
diff --git a/arch/arm/plat-versatile/sched-clock.c b/arch/arm/plat-versatile/sched-clock.c
new file mode 100644
index 00000000000..9768cf7e83d
--- /dev/null
+++ b/arch/arm/plat-versatile/sched-clock.c
@@ -0,0 +1,53 @@
+/*
+ * linux/arch/arm/plat-versatile/sched-clock.c
+ *
+ * Copyright (C) 1999 - 2003 ARM Limited
+ * Copyright (C) 2000 Deep Blue Solutions Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <linux/cnt32_to_63.h>
+#include <linux/io.h>
+#include <asm/div64.h>
+
+#include <mach/hardware.h>
+#include <mach/platform.h>
+
+#ifdef VERSATILE_SYS_BASE
+#define REFCOUNTER (__io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_24MHz_OFFSET)
+#endif
+
+#ifdef REALVIEW_SYS_BASE
+#define REFCOUNTER (__io_address(REALVIEW_SYS_BASE) + REALVIEW_SYS_24MHz_OFFSET)
+#endif
+
+/*
+ * This is the Realview and Versatile sched_clock implementation. This
+ * has a resolution of 41.7ns, and a maximum value of about 35583 days.
+ *
+ * The return value is guaranteed to be monotonic in that range as
+ * long as there is always less than 89 seconds between successive
+ * calls to this function.
+ */
+unsigned long long sched_clock(void)
+{
+ unsigned long long v = cnt32_to_63(readl(REFCOUNTER));
+
+ /* the <<1 gets rid of the cnt_32_to_63 top bit saving on a bic insn */
+ v *= 125<<1;
+ do_div(v, 3<<1);
+
+ return v;
+}