sched_clock: Make ARM's sched_clock generic for all architectures

Nothing about the sched_clock implementation in the ARM port is
specific to the architecture. Generalize the code so that other
architectures can use it by selecting GENERIC_SCHED_CLOCK.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[jstultz: Merge minor collisions with other patches in my tree]
Signed-off-by: John Stultz <john.stultz@linaro.org>

4 files changed, 3 insertions, 221 deletions

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 5f3338eacad2..97cb0576d07c 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -16,7 +16,7 @@ CFLAGS_REMOVE_return_address.o = -pg
 # Object file lists.
 
 obj-y           := elf.o entry-armv.o entry-common.o irq.o opcodes.o \
-                   process.o ptrace.o return_address.o sched_clock.o \
+                   process.o ptrace.o return_address.o \
                    setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
 obj-$(CONFIG_ATAGS)             += atags_parse.o
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index 59dcdced6e30..221f07b11ccb 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -11,9 +11,9 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/errno.h>
+#include <linux/sched_clock.h>
 
 #include <asm/delay.h>
-#include <asm/sched_clock.h>
 
 #include <clocksource/arm_arch_timer.h>
 
diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
deleted file mode 100644
index a781c59b93c0..000000000000
--- a/arch/arm/kernel/sched_clock.c
+++ /dev/null
@@ -1,216 +0,0 @@
-/*
- * 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/moduleparam.h>
-#include <linux/sched.h>
-#include <linux/syscore_ops.h>
-#include <linux/timer.h>
-
-#include <asm/sched_clock.h>
-
-struct clock_data {
-        u64 epoch_ns;
-        u32 epoch_cyc;
-        u32 epoch_cyc_copy;
-        unsigned long rate;
-        u32 mult;
-        u32 shift;
-        bool suspended;
-};
-
-static void sched_clock_poll(unsigned long wrap_ticks);
-static DEFINE_TIMER(sched_clock_timer, sched_clock_poll, 0, 0);
-static int irqtime = -1;
-
-core_param(irqtime, irqtime, int, 0400);
-
-static struct clock_data cd = {
-        .mult   = NSEC_PER_SEC / HZ,
-};
-
-static u32 __read_mostly sched_clock_mask = 0xffffffff;
-
-static u32 notrace jiffy_sched_clock_read(void)
-{
-        return (u32)(jiffies - INITIAL_JIFFIES);
-}
-
-static u32 __read_mostly (*read_sched_clock)(void) = jiffy_sched_clock_read;
-
-static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
-{
-        return (cyc * mult) >> shift;
-}
-
-static unsigned long long notrace cyc_to_sched_clock(u32 cyc, u32 mask)
-{
-        u64 epoch_ns;
-        u32 epoch_cyc;
-
-        /*
-         * Load the epoch_cyc and epoch_ns atomically.  We do this by
-         * ensuring that we always write epoch_cyc, epoch_ns and
-         * epoch_cyc_copy in strict order, and read them in strict order.
-         * If epoch_cyc and epoch_cyc_copy are not equal, then we're in
-         * the middle of an update, and we should repeat the load.
-         */
-        do {
-                epoch_cyc = cd.epoch_cyc;
-                smp_rmb();
-                epoch_ns = cd.epoch_ns;
-                smp_rmb();
-        } while (epoch_cyc != cd.epoch_cyc_copy);
-
-        return epoch_ns + cyc_to_ns((cyc - epoch_cyc) & mask, cd.mult, cd.shift);
-}
-
-/*
- * Atomically update the sched_clock epoch.
- */
-static void notrace update_sched_clock(void)
-{
-        unsigned long flags;
-        u32 cyc;
-        u64 ns;
-
-        cyc = read_sched_clock();
-        ns = cd.epoch_ns +
-                cyc_to_ns((cyc - cd.epoch_cyc) & sched_clock_mask,
-                          cd.mult, cd.shift);
-        /*
-         * Write epoch_cyc and epoch_ns in a way that the update is
-         * detectable in cyc_to_fixed_sched_clock().
-         */
-        raw_local_irq_save(flags);
-        cd.epoch_cyc_copy = cyc;
-        smp_wmb();
-        cd.epoch_ns = ns;
-        smp_wmb();
-        cd.epoch_cyc = cyc;
-        raw_local_irq_restore(flags);
-}
-
-static void sched_clock_poll(unsigned long wrap_ticks)
-{
-        mod_timer(&sched_clock_timer, round_jiffies(jiffies + wrap_ticks));
-        update_sched_clock();
-}
-
-void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
-{
-        unsigned long r, w;
-        u64 res, wrap;
-        char r_unit;
-
-        if (cd.rate > rate)
-                return;
-
-        BUG_ON(bits > 32);
-        WARN_ON(!irqs_disabled());
-        read_sched_clock = read;
-        sched_clock_mask = (1 << bits) - 1;
-        cd.rate = rate;
-
-        /* 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 if (r >= 1000) {
-                r /= 1000;
-                r_unit = 'k';
-        } else
-                r_unit = ' ';
-
-        /* calculate how many ns until we wrap */
-        wrap = cyc_to_ns((1ULL << 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",
-                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_sched_clock();
-
-        /*
-         * Ensure that sched_clock() starts off at 0ns
-         */
-        cd.epoch_ns = 0;
-
-        /* Enable IRQ time accounting if we have a fast enough sched_clock */
-        if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
-                enable_sched_clock_irqtime();
-
-        pr_debug("Registered %pF as sched_clock source\n", read);
-}
-
-static unsigned long long notrace sched_clock_32(void)
-{
-        u32 cyc = read_sched_clock();
-        return cyc_to_sched_clock(cyc, sched_clock_mask);
-}
-
-unsigned long long __read_mostly (*sched_clock_func)(void) = sched_clock_32;
-
-unsigned long long notrace sched_clock(void)
-{
-        if (cd.suspended)
-                return cd.epoch_ns;
-
-        return sched_clock_func();
-}
-
-void __init sched_clock_postinit(void)
-{
-        /*
-         * If no sched_clock function has been provided at that point,
-         * make it the final one one.
-         */
-        if (read_sched_clock == jiffy_sched_clock_read)
-                setup_sched_clock(jiffy_sched_clock_read, 32, HZ);
-
-        sched_clock_poll(sched_clock_timer.data);
-}
-
-static int sched_clock_suspend(void)
-{
-        sched_clock_poll(sched_clock_timer.data);
-        cd.suspended = true;
-        return 0;
-}
-
-static void sched_clock_resume(void)
-{
-        cd.epoch_cyc = read_sched_clock();
-        cd.epoch_cyc_copy = cd.epoch_cyc;
-        cd.suspended = false;
-}
-
-static struct syscore_ops sched_clock_ops = {
-        .suspend = sched_clock_suspend,
-        .resume = sched_clock_resume,
-};
-
-static int __init sched_clock_syscore_init(void)
-{
-        register_syscore_ops(&sched_clock_ops);
-        return 0;
-}
-device_initcall(sched_clock_syscore_init);
diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index abff4e9aaee0..98aee3258398 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -24,9 +24,9 @@
 #include <linux/timer.h>
 #include <linux/clocksource.h>
 #include <linux/irq.h>
+#include <linux/sched_clock.h>
 
 #include <asm/thread_info.h>
-#include <asm/sched_clock.h>
 #include <asm/stacktrace.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
@@ -120,6 +120,4 @@ void __init time_init(void)
                 machine_desc->init_time();
         else
                 clocksource_of_init();
-
-        sched_clock_postinit();
 }