From 5c2112a210e8654d96e3f4c0395f1a326f28666f Mon Sep 17 00:00:00 2001
From: Namhoon Kim <namhoonk@cs.unc.edu>
Date: Mon, 3 Nov 2014 21:52:24 -0500
Subject: ARM timer support

---
 include/litmus/clock.h         | 48 ++++++++++++++++++++++++++++++++++++++
 include/litmus/feather_trace.h | 12 ++++++++++
 litmus/litmus.c                | 53 +++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 include/litmus/clock.h

diff --git a/include/litmus/clock.h b/include/litmus/clock.h
new file mode 100644
index 000000000000..f8de7a3dfb5a
--- /dev/null
+++ b/include/litmus/clock.h
@@ -0,0 +1,48 @@
+#ifndef _LITMUS_CLOCK_H_
+#define _LITMUS_CLOCK_H_
+
+#if defined(CONFIG_EXYNOS_MCT)
+
+/*
+ * Only used if we are using the EXYNOS MCT clock.
+ */
+
+#include <linux/clocksource.h>
+extern struct clocksource mct_frc;
+
+static inline cycles_t mct_frc_read(void)
+{
+	cycle_t cycles = mct_frc.read(&mct_frc);
+	return cycles;
+}
+
+static inline s64 litmus_cycles_to_ns(cycles_t cycles)
+{
+	return clocksource_cyc2ns(cycles, mct_frc.mult, mct_frc.shift);
+}
+
+#define litmus_get_cycles mct_frc_read
+
+#elif defined(CONFIG_CPU_V7) && !defined(CONFIG_HW_PERF_EVENTS)
+
+#include <asm/timex.h>
+
+static inline cycles_t v7_get_cycles (void)
+{
+	u32 value;
+        /* read CCNT register */
+        asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"(value));
+	return value;
+}
+
+#define litmus_get_cycles v7_get_cycles
+
+#else
+#include <asm/timex.h>
+
+#define litmus_get_cycles get_cycles
+
+#endif
+
+#endif
+
diff --git a/include/litmus/feather_trace.h b/include/litmus/feather_trace.h
index dbeca46c01f5..cc4396e7fbe4 100644
--- a/include/litmus/feather_trace.h
+++ b/include/litmus/feather_trace.h
@@ -38,11 +38,23 @@ static inline void ft_atomic_dec(int *val)
 /* provide default implementation */
 #include <linux/timex.h> /* for get_cycles() */
 
+#if defined(CONFIG_CPU_V7) && !defined(CONFIG_HW_PERF_EVENTS)	
+
+#include <litmus/clock.h> /* for litmus_get_cycles() */
+static inline unsigned long long ft_timestamp(void)
+{
+	return (unsigned long long)litmus_get_cycles();
+}
+
+#else
+
 static inline unsigned long long ft_timestamp(void)
 {
 	return get_cycles();
 }
 
+#endif
+
 #define feather_callback
 
 #define MAX_EVENTS 1024
diff --git a/litmus/litmus.c b/litmus/litmus.c
index a061343ab769..14b1031fc6c7 100644
--- a/litmus/litmus.c
+++ b/litmus/litmus.c
@@ -20,6 +20,9 @@
 #include <litmus/rt_domain.h>
 #include <litmus/litmus_proc.h>
 #include <litmus/sched_trace.h>
+#include <litmus/clock.h>
+
+#include <asm/cacheflush.h>
 
 #ifdef CONFIG_SCHED_CPU_AFFINITY
 #include <litmus/affinity.h>
@@ -303,9 +306,11 @@ asmlinkage long sys_null_call(cycles_t __user *ts)
 	cycles_t now;
 
 	if (ts) {
-		now = get_cycles();
+		now = litmus_get_cycles();
 		ret = put_user(now, ts);
 	}
+	else
+		flush_cache_all();
 
 	return ret;
 }
@@ -599,6 +604,48 @@ static struct notifier_block shutdown_notifier = {
 	.notifier_call = litmus_shutdown_nb,
 };
 
+#if defined(CONFIG_CPU_V7) && !defined(CONFIG_HW_PERF_EVENTS)
+static void __init litmus_enable_perfcounters_v7(void *_ignore)
+{
+	u32 enable_val = 0;
+
+	/* disable performance monitoring */
+	asm volatile("mcr p15, 0, %0, c9, c12, 0" : : "r" (0x00000006));
+
+	/* disable all events */
+	asm volatile("mcr p15, 0, %0, c9, c12, 2" : : "r" (0xffffffff));
+
+	/* write 1 to enable user-mode access to the performance counter */
+	asm volatile("mcr p15, 0, %0, c9, c14, 0" : : "r" (1));
+
+	/* disable counter overflow interrupts (just in case) */
+	asm volatile("mcr p15, 0, %0, c9, c14, 2" : : "r" (0x8000000f));
+
+	/* select event zero */
+	asm volatile("mcr p15, 0, %0, c9, c12, 5" : : "r" (0));
+
+	/* count cycles in the selected event zero */
+	asm volatile("mcr p15, 0, %0, c9, c13, 1" : : "r" (0x00000011));
+
+	enable_val |= 1;	/* bit 1 enables the counters */
+	enable_val |= 2;	/* resets event counters to zero */
+	enable_val |= 4;	/* resets cycle counter to zero */
+	//enable_val |= 8;	/* enable "by 64" divider for CCNT. */
+	
+	/* performance monitor control register: enable all counters */
+	asm volatile("mcr p15, 0, %0, c9, c12, 0" : : "r"(enable_val));
+
+	/* enables counters (cycle counter and event 1) */
+        asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r"(0x80000001));
+}
+
+static void __init litmus_enable_perfcounters(void)
+{
+	litmus_enable_perfcounters_v7(NULL);
+	smp_call_function(litmus_enable_perfcounters_v7, NULL, 0);
+}
+#endif
+
 static int __init _init_litmus(void)
 {
 	/*      Common initializers,
@@ -628,6 +675,10 @@ static int __init _init_litmus(void)
 
 	register_reboot_notifier(&shutdown_notifier);
 
+#if defined(CONFIG_CPU_V7) && !defined(CONFIG_HW_PERF_EVENTS)	
+	litmus_enable_perfcounters();
+#endif
+	
 	return 0;
 }
 
-- 
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