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authorStephen Boyd <sboyd@codeaurora.org>2013-07-18 16:21:18 -0700
committerJohn Stultz <john.stultz@linaro.org>2013-10-09 16:54:10 -0700
commit65cd4f6c99c1170bd0114dbd71b978012ea44d28 (patch)
treefbde89149eb5032b49875cddf728d598ffd349ad
parent07783397c6e3757de805bda5e1139a9e47aa7d74 (diff)
arch_timer: Move to generic sched_clock framework
Register with the generic sched_clock framework now that it supports 64 bits. This fixes two problems with the current sched_clock support for machines using the architected timers. First off, we don't subtract the start value from subsequent sched_clock calls so we can potentially start off with sched_clock returning gigantic numbers. Second, there is no support for suspend/resume handling so problems such as discussed in 6a4dae5 (ARM: 7565/1: sched: stop sched_clock() during suspend, 2012-10-23) can happen without this patch. Finally, it allows us to move the sched_clock setup into drivers clocksource out of the arch ports. Cc: Christopher Covington <cov@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
-rw-r--r--arch/arm/kernel/arch_timer.c14
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/kernel/time.c10
-rw-r--r--drivers/clocksource/arm_arch_timer.c10
4 files changed, 11 insertions, 24 deletions
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index 221f07b11ccb..1791f12c180b 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -11,7 +11,6 @@
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
-#include <linux/sched_clock.h>
#include <asm/delay.h>
@@ -22,13 +21,6 @@ static unsigned long arch_timer_read_counter_long(void)
return arch_timer_read_counter();
}
-static u32 sched_clock_mult __read_mostly;
-
-static unsigned long long notrace arch_timer_sched_clock(void)
-{
- return arch_timer_read_counter() * sched_clock_mult;
-}
-
static struct delay_timer arch_delay_timer;
static void __init arch_timer_delay_timer_register(void)
@@ -48,11 +40,5 @@ int __init arch_timer_arch_init(void)
arch_timer_delay_timer_register();
- /* Cache the sched_clock multiplier to save a divide in the hot path. */
- sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
- sched_clock_func = arch_timer_sched_clock;
- pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %uns\n",
- arch_timer_rate / 1000, sched_clock_mult);
-
return 0;
}
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c04454876bcb..35fd0eb57270 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -14,6 +14,7 @@ config ARM64
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
+ select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
select HARDIRQS_SW_RESEND
diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index 03dc3718eb13..29c39d5d77e3 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -61,13 +61,6 @@ unsigned long profile_pc(struct pt_regs *regs)
EXPORT_SYMBOL(profile_pc);
#endif
-static u64 sched_clock_mult __read_mostly;
-
-unsigned long long notrace sched_clock(void)
-{
- return arch_timer_read_counter() * sched_clock_mult;
-}
-
void __init time_init(void)
{
u32 arch_timer_rate;
@@ -78,9 +71,6 @@ void __init time_init(void)
if (!arch_timer_rate)
panic("Unable to initialise architected timer.\n");
- /* Cache the sched_clock multiplier to save a divide in the hot path. */
- sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
-
/* Calibrate the delay loop directly */
lpj_fine = arch_timer_rate / HZ;
}
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index fbd9ccd5e114..5d527895c74d 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -19,6 +19,7 @@
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/slab.h>
+#include <linux/sched_clock.h>
#include <asm/arch_timer.h>
#include <asm/virt.h>
@@ -471,6 +472,15 @@ static int __init arch_timer_register(void)
goto out;
}
+ clocksource_register_hz(&clocksource_counter, arch_timer_rate);
+ cyclecounter.mult = clocksource_counter.mult;
+ cyclecounter.shift = clocksource_counter.shift;
+ timecounter_init(&timecounter, &cyclecounter,
+ arch_counter_get_cntvct());
+
+ /* 56 bits minimum, so we assume worst case rollover */
+ sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
+
if (arch_timer_use_virtual) {
ppi = arch_timer_ppi[VIRT_PPI];
err = request_percpu_irq(ppi, arch_timer_handler_virt,