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authorHans-Christian Egtvedt <hcegtvedt@atmel.com>2007-02-26 07:50:43 -0500
committerHaavard Skinnemoen <hskinnemoen@atmel.com>2007-04-27 07:44:12 -0400
commit19b7ce8bad718a2850ea19aeb7383f1728596c24 (patch)
tree1fef17c37eaf90231a497b92dd49565e56986b6c /arch
parent7760989e5e2900e484e9115e6e690c6ce0b0221c (diff)
[AVR32] Put cpu in sleep 0 when idle.
This patch puts the CPU in sleep 0 when doing nothing, idle. This will turn of the CPU clock and thus save power. The CPU is waken again when an interrupt occurs. Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com> Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/avr32/kernel/entry-avr32b.S42
-rw-r--r--arch/avr32/kernel/process.c5
2 files changed, 40 insertions, 7 deletions
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index eeb66792bc37..5f5f7e42f51b 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -630,9 +630,12 @@ irq_level\level:
630 rcall do_IRQ 630 rcall do_IRQ
631 631
632 lddsp r4, sp[REG_SR] 632 lddsp r4, sp[REG_SR]
633 andh r4, (MODE_MASK >> 16), COH 633 bfextu r4, r4, SYSREG_M0_OFFSET, 3
634 cp.w r4, MODE_SUPERVISOR >> SYSREG_M0_OFFSET
635 breq 2f
636 cp.w r4, MODE_USER >> SYSREG_M0_OFFSET
634#ifdef CONFIG_PREEMPT 637#ifdef CONFIG_PREEMPT
635 brne 2f 638 brne 3f
636#else 639#else
637 brne 1f 640 brne 1f
638#endif 641#endif
@@ -649,9 +652,18 @@ irq_level\level:
649 sub sp, -4 /* ignore r12_orig */ 652 sub sp, -4 /* ignore r12_orig */
650 rete 653 rete
651 654
6552: get_thread_info r0
656 ld.w r1, r0[TI_flags]
657 bld r1, TIF_CPU_GOING_TO_SLEEP
652#ifdef CONFIG_PREEMPT 658#ifdef CONFIG_PREEMPT
6532: 659 brcc 3f
654 get_thread_info r0 660#else
661 brcc 1b
662#endif
663 sub r1, pc, . - cpu_idle_skip_sleep
664 stdsp sp[REG_PC], r1
665#ifdef CONFIG_PREEMPT
6663: get_thread_info r0
655 ld.w r2, r0[TI_preempt_count] 667 ld.w r2, r0[TI_preempt_count]
656 cp.w r2, 0 668 cp.w r2, 0
657 brne 1b 669 brne 1b
@@ -662,12 +674,32 @@ irq_level\level:
662 bld r4, SYSREG_GM_OFFSET 674 bld r4, SYSREG_GM_OFFSET
663 brcs 1b 675 brcs 1b
664 rcall preempt_schedule_irq 676 rcall preempt_schedule_irq
665 rjmp 1b
666#endif 677#endif
678 rjmp 1b
667 .endm 679 .endm
668 680
669 .section .irq.text,"ax",@progbits 681 .section .irq.text,"ax",@progbits
670 682
683.global cpu_idle_sleep
684cpu_idle_sleep:
685 mask_interrupts
686 get_thread_info r8
687 ld.w r9, r8[TI_flags]
688 bld r9, TIF_NEED_RESCHED
689 brcs cpu_idle_enable_int_and_exit
690 sbr r9, TIF_CPU_GOING_TO_SLEEP
691 st.w r8[TI_flags], r9
692 unmask_interrupts
693 sleep 0
694cpu_idle_skip_sleep:
695 mask_interrupts
696 ld.w r9, r8[TI_flags]
697 cbr r9, TIF_CPU_GOING_TO_SLEEP
698 st.w r8[TI_flags], r9
699cpu_idle_enable_int_and_exit:
700 unmask_interrupts
701 retal r12
702
671 .global irq_level0 703 .global irq_level0
672 .global irq_level1 704 .global irq_level1
673 .global irq_level2 705 .global irq_level2
diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
index 0b4325946a41..4f8d2d474740 100644
--- a/arch/avr32/kernel/process.c
+++ b/arch/avr32/kernel/process.c
@@ -19,6 +19,8 @@
19void (*pm_power_off)(void) = NULL; 19void (*pm_power_off)(void) = NULL;
20EXPORT_SYMBOL(pm_power_off); 20EXPORT_SYMBOL(pm_power_off);
21 21
22extern void cpu_idle_sleep(void);
23
22/* 24/*
23 * This file handles the architecture-dependent parts of process handling.. 25 * This file handles the architecture-dependent parts of process handling..
24 */ 26 */
@@ -27,9 +29,8 @@ void cpu_idle(void)
27{ 29{
28 /* endless idle loop with no priority at all */ 30 /* endless idle loop with no priority at all */
29 while (1) { 31 while (1) {
30 /* TODO: Enter sleep mode */
31 while (!need_resched()) 32 while (!need_resched())
32 cpu_relax(); 33 cpu_idle_sleep();
33 preempt_enable_no_resched(); 34 preempt_enable_no_resched();
34 schedule(); 35 schedule();
35 preempt_disable(); 36 preempt_disable();