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Commit 19b7ce8b authored by Hans-Christian Egtvedt's avatar Hans-Christian Egtvedt Committed by Haavard Skinnemoen
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[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: default avatarHans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: default avatarHaavard Skinnemoen <hskinnemoen@atmel.com>
parent 7760989e

arch/avr32/kernel/entry-avr32b.S

+37 −5
Original line number Diff line number Diff line
@@ -630,9 +630,12 @@ irq_level\level: 
	rcall	do_IRQ



	lddsp	r4, sp[REG_SR]

	andh	r4, (MODE_MASK >> 16), COH

	bfextu	r4, r4, SYSREG_M0_OFFSET, 3

	cp.w	r4, MODE_SUPERVISOR >> SYSREG_M0_OFFSET

	breq	2f

	cp.w	r4, MODE_USER >> SYSREG_M0_OFFSET

#ifdef CONFIG_PREEMPT

	brne	2f

	brne	3f

#else

	brne	1f

#endif
@@ -649,9 +652,18 @@ irq_level\level: 
	sub	sp, -4		/* ignore r12_orig */

	rete



2:	get_thread_info	r0

	ld.w	r1, r0[TI_flags]

	bld	r1, TIF_CPU_GOING_TO_SLEEP

#ifdef CONFIG_PREEMPT

2:

	get_thread_info	r0

	brcc	3f

#else

	brcc	1b

#endif

	sub	r1, pc, . - cpu_idle_skip_sleep

	stdsp	sp[REG_PC], r1

#ifdef CONFIG_PREEMPT

3:	get_thread_info r0

	ld.w	r2, r0[TI_preempt_count]

	cp.w	r2, 0

	brne	1b
@@ -662,12 +674,32 @@ irq_level\level: 
	bld	r4, SYSREG_GM_OFFSET

	brcs	1b

	rcall	preempt_schedule_irq

	rjmp	1b

#endif

	rjmp	1b

	.endm



	.section .irq.text,"ax",@progbits



.global cpu_idle_sleep

cpu_idle_sleep:

	mask_interrupts

	get_thread_info r8

	ld.w	r9, r8[TI_flags]

	bld	r9, TIF_NEED_RESCHED

	brcs	cpu_idle_enable_int_and_exit

	sbr	r9, TIF_CPU_GOING_TO_SLEEP

	st.w	r8[TI_flags], r9

	unmask_interrupts

	sleep 0

cpu_idle_skip_sleep:

	mask_interrupts

	ld.w	r9, r8[TI_flags]

	cbr	r9, TIF_CPU_GOING_TO_SLEEP

	st.w	r8[TI_flags], r9

cpu_idle_enable_int_and_exit:

	unmask_interrupts

	retal	r12



	.global	irq_level0

	.global	irq_level1

	.global	irq_level2

arch/avr32/kernel/process.c

+3 −2
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
void (*pm_power_off)(void) = NULL;

EXPORT_SYMBOL(pm_power_off);



extern void cpu_idle_sleep(void);



/*

 * This file handles the architecture-dependent parts of process handling..

 */
@@ -27,9 +29,8 @@ void cpu_idle(void) 
{

	/* endless idle loop with no priority at all */

	while (1) {

		/* TODO: Enter sleep mode */

		while (!need_resched())

			cpu_relax();

			cpu_idle_sleep();

		preempt_enable_no_resched();

		schedule();

		preempt_disable();

include/asm-avr32/thread_info.h

+2 −0
Original line number Diff line number Diff line
@@ -83,6 +83,7 @@ static inline struct thread_info *current_thread_info(void) 
#define TIF_SINGLE_STEP		6	/* single step after next break */

#define TIF_MEMDIE		7

#define TIF_RESTORE_SIGMASK	8	/* restore signal mask in do_signal */

#define TIF_CPU_GOING_TO_SLEEP	9	/* CPU is entering sleep 0 mode */

#define TIF_USERSPACE		31      /* true if FS sets userspace */



#define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
@@ -94,6 +95,7 @@ static inline struct thread_info *current_thread_info(void) 
#define _TIF_SINGLE_STEP	(1 << TIF_SINGLE_STEP)

#define _TIF_MEMDIE		(1 << TIF_MEMDIE)

#define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)

#define _TIF_CPU_GOING_TO_SLEEP (1 << TIF_CPU_GOING_TO_SLEEP)



/* XXX: These two masks must never span more than 16 bits! */

/* work to do on interrupt/exception return */