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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2005-06-25 19:39:45 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2005-06-25 19:39:45 +0100
commit8749af68216e1ebf6460992fce548f400ecf63a4 (patch)
tree6968809c357c1cf8167208f480f0e974bf9af955 /arch/arm/kernel/irq.c
parent321ab6a5fab812658626aee6bce2617f8cfb3a55 (diff)
downloadlinux-8749af68216e1ebf6460992fce548f400ecf63a4.tar.bz2
[PATCH] ARM: Generic Dynamic Tick Timer support for ARM, take 4
This patch adds support for Dynamic Tick Timer for ARM. Dynamic Tick is also known as VST (Variable Scheduling Timeouts). Dynamic Tick has been in use in the OMAP tree since last October. The patch is not intrusive, and does not do anything unless CONFIG_NO_IDLE_HZ is defined. This patch has the following fixed based on comments from RMK: - Time is updated before calling interrupt handlers. - Added new interrupt flag SA_TIMER to avoid duplicate timer interrupts - Moved struct dyn_tick_timer to time.h until we at some point probably have an arch independent dyn-tick.h - Cleaned up testing for DYN_TICK_ENABLED in irq.c I've cleaned up this patch to fix some remaining issues: - Call the timer tick handler with irqs disabled, as it would be from a normal interrupt - if we have a dyn_tick, we better implement all methods. - generic timer_dyn_reprogram() call, to be called before sleeping - added command line option - "dyntick=" to allow boot-time control of this feature -- rmk Signed-off-by: Tony Lindgren Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/irq.c')
-rw-r--r--arch/arm/kernel/irq.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index ff187f4308f0..395137a8fad2 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -4,6 +4,10 @@
* Copyright (C) 1992 Linus Torvalds
* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
*
+ * Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
+ * Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
+ * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
+ *
* 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.
@@ -37,6 +41,7 @@
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/mach/irq.h>
+#include <asm/mach/time.h>
/*
* Maximum IRQ count. Currently, this is arbitary. However, it should
@@ -329,6 +334,15 @@ __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
spin_unlock(&irq_controller_lock);
+#ifdef CONFIG_NO_IDLE_HZ
+ if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
+ write_seqlock(&xtime_lock);
+ if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
+ system_timer->dyn_tick->handler(irq, 0, regs);
+ write_sequnlock(&xtime_lock);
+ }
+#endif
+
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();