[RFC PATCH 2/2] clocksource: dw_apb: allow build for architectures other than arm

[Baruch Siach <baruch@tkos.co.il>]

ARM is the only architecture providing sched_clock.h and setup_sched_clock().
Implement sched_clock() for use by other architectures.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Dinh Nguyen <dinguyen@altera.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
 arch/arm/Kconfig                      |    1 +
 drivers/clocksource/Kconfig           |    3 +++
 drivers/clocksource/dw_apb_timer_of.c |   18 ++++++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1cacda4..7489604 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -47,6 +47,7 @@ config ARM
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_SETUP_SCHED_CLOCK
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UID16
 	select KTIME_SCALAR
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index e507ab7..0fd6d13 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -1,3 +1,6 @@
+config HAVE_SETUP_SCHED_CLOCK
+	bool
+
 config CLKSRC_OF
 	bool
 
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index 5a61ebc..9fdb4d3 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -21,7 +21,11 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
+#ifdef CONFIG_HAVE_SETUP_SCHED_CLOCK
 #include <asm/sched_clock.h>
+#else
+#include <linux/sched.h>
+#endif
 
 static void timer_get_base_and_rate(struct device_node *np,
 				    void __iomem **base, u32 *rate)
@@ -73,6 +77,9 @@ static void add_clocksource(struct device_node *source_timer)
 }
 
 static void __iomem *sched_io_base;
+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK
+static u64 sched_clock_mult __read_mostly;
+#endif
 
 static u32 read_sched_clock(void)
 {
@@ -97,7 +104,11 @@ static void init_sched_clock(void)
 	timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
 	of_node_put(sched_timer);
 
+#ifdef CONFIG_HAVE_SETUP_SCHED_CLOCK
 	setup_sched_clock(read_sched_clock, 32, rate);
+#else
+	sched_clock_mult = NSEC_PER_SEC / rate;
+#endif
 }
 
 static const struct of_device_id osctimer_ids[] __initconst = {
@@ -124,3 +135,10 @@ void __init dw_apb_timer_init(void)
 
 	init_sched_clock();
 }
+
+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK
+unsigned long long notrace sched_clock()
+{
+	return read_sched_clock() * sched_clock_mult;
+}
+#endif
-- 
1.7.10.4