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authorWill Deacon <will.deacon@arm.com>2012-07-06 15:46:45 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-07-09 17:42:23 +0100
commit923df96b9f31b7d08d8438ff9677326d9537accf (patch)
tree3df937a0431a2ae0500ae011f5742a28611490fa /arch/arm/kernel/arch_timer.c
parentf8f5701bdaf9134b1f90e5044a82c66324d2073f (diff)
downloadlinux-923df96b9f31b7d08d8438ff9677326d9537accf.tar.bz2
ARM: 7451/1: arch timer: implement read_current_timer and get_cycles
This patch implements read_current_timer using the architected timers when they are selected via CONFIG_ARM_ARCH_TIMER. If they are detected not to be usable at runtime, we return -ENXIO to the caller. Furthermore, if read_current_timer is exported then we can implement get_cycles in terms of it for use as both an entropy source and for implementing __udelay and friends. Tested-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/arch_timer.c')
-rw-r--r--arch/arm/kernel/arch_timer.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index dd58035621f7..dbbeec4f06e2 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -223,6 +223,14 @@ static cycle_t arch_counter_read(struct clocksource *cs)
return arch_counter_get_cntpct();
}
+int read_current_timer(unsigned long *timer_val)
+{
+ if (!arch_timer_rate)
+ return -ENXIO;
+ *timer_val = arch_counter_get_cntpct();
+ return 0;
+}
+
static struct clocksource clocksource_counter = {
.name = "arch_sys_counter",
.rating = 400,