[PATCH -v4 3/9] tracing: add MIPS specific trace_clock_local()

[Wu Zhangjin <wuzhangjin@gmail.com>]

This patch add the mips_timecounter_read() based high precision version
of trace_clock_local().

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
---
 arch/mips/kernel/Makefile      |    6 ++++++
 arch/mips/kernel/trace_clock.c |   37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/kernel/trace_clock.c

diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 8e26e9c..f228868 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -8,6 +8,10 @@ obj-y          += cpu-probe.o branch.o entry.o genex.o irq.o 
process.o \
                   ptrace.o reset.o setup.o signal.o syscall.o \
                   time.o topology.o traps.o unaligned.o watch.o
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_trace_clock.o = -pg
+endif
+
 obj-$(CONFIG_CEVT_BCM1480)     += cevt-bcm1480.o
 obj-$(CONFIG_CEVT_R4K_LIB)     += cevt-r4k.o
 obj-$(CONFIG_MIPS_MT_SMTC)     += cevt-smtc.o
@@ -24,6 +28,8 @@ obj-$(CONFIG_SYNC_R4K)                += sync-r4k.o
 obj-$(CONFIG_STACKTRACE)       += stacktrace.o
 obj-$(CONFIG_MODULES)          += mips_ksyms.o module.o
 
+obj-$(CONFIG_FTRACE)           += trace_clock.o
+
 obj-$(CONFIG_CPU_LOONGSON2)    += r4k_fpu.o r4k_switch.o
 obj-$(CONFIG_CPU_MIPS32)       += r4k_fpu.o r4k_switch.o
 obj-$(CONFIG_CPU_MIPS64)       += r4k_fpu.o r4k_switch.o
diff --git a/arch/mips/kernel/trace_clock.c b/arch/mips/kernel/trace_clock.c
new file mode 100644
index 0000000..2e3475f
--- /dev/null
+++ b/arch/mips/kernel/trace_clock.c
@@ -0,0 +1,37 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive for
+ * more details.
+ *
+ * Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
+ * Author: Wu Zhangjin <wuzj@lemote.com>
+ */
+
+#include <linux/clocksource.h>
+#include <linux/sched.h>
+
+#include <asm/time.h>
+
+/*
+ * trace_clock_local(): the simplest and least coherent tracing clock.
+ *
+ * Useful for tracing that does not cross to other CPUs nor
+ * does it go through idle events.
+ */
+u64 trace_clock_local(void)
+{
+       unsigned long flags;
+       u64 clock;
+
+       raw_local_irq_save(flags);
+
+       preempt_disable_notrace();
+
+       clock = mips_timecounter_read();
+
+       preempt_enable_no_resched_notrace();
+
+       raw_local_irq_restore(flags);
+
+       return clock;
+}
-- 
1.6.2.1