Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 74 insertions, 0 deletions

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
new file mode 100644
index 000000000000..9a46370fe9da
--- /dev/null
+++ b/arch/arm/kernel/sched_clock.c
@@ -0,0 +1,74 @@
+/*
+ * sched_clock.c: support for extending counters to full 64-bit ns counter
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+
+#include <asm/sched_clock.h>
+
+static void sched_clock_poll(unsigned long wrap_ticks);
+static DEFINE_TIMER(sched_clock_timer, sched_clock_poll, 0, 0);
+static void (*sched_clock_update_fn)(void);
+
+static void sched_clock_poll(unsigned long wrap_ticks)
+{
+        mod_timer(&sched_clock_timer, round_jiffies(jiffies + wrap_ticks));
+        sched_clock_update_fn();
+}
+
+void __init init_sched_clock(struct clock_data *cd, void (*update)(void),
+        unsigned int clock_bits, unsigned long rate)
+{
+        unsigned long r, w;
+        u64 res, wrap;
+        char r_unit;
+
+        sched_clock_update_fn = update;
+
+        /* calculate the mult/shift to convert counter ticks to ns. */
+        clocks_calc_mult_shift(&cd->mult, &cd->shift, rate, NSEC_PER_SEC, 0);
+
+        r = rate;
+        if (r >= 4000000) {
+                r /= 1000000;
+                r_unit = 'M';
+        } else {
+                r /= 1000;
+                r_unit = 'k';
+        }
+
+        /* calculate how many ns until we wrap */
+        wrap = cyc_to_ns((1ULL << clock_bits) - 1, cd->mult, cd->shift);
+        do_div(wrap, NSEC_PER_MSEC);
+        w = wrap;
+
+        /* calculate the ns resolution of this counter */
+        res = cyc_to_ns(1ULL, cd->mult, cd->shift);
+        pr_info("sched_clock: %u bits at %lu%cHz, resolution %lluns, wraps every %lums\n",
+                clock_bits, r, r_unit, res, w);
+
+        /*
+         * Start the timer to keep sched_clock() properly updated and
+         * sets the initial epoch.
+         */
+        sched_clock_timer.data = msecs_to_jiffies(w - (w / 10));
+        update();
+
+        /*
+         * Ensure that sched_clock() starts off at 0ns
+         */
+        cd->epoch_ns = 0;
+}
+
+void __init sched_clock_postinit(void)
+{
+        sched_clock_poll(sched_clock_timer.data);
+}