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Add an idle loop routine for the QED RM52xx family. This uses the 

RM52xx `wait' insn to power down the pipeline.
This commit is contained in:
thorpej 2001-05-29 17:51:55 +00:00
parent d0c243e9e5
commit c8988c2caa
1 changed files with 72 additions and 1 deletions
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73
sys/arch/mips/mips/locore_mips3.S
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@ -1,4 +1,4 @@
/* $NetBSD: locore_mips3.S,v 1.66 2001/01/20 07:23:21 ur Exp $ */
/* $NetBSD: locore_mips3.S,v 1.67 2001/05/29 17:51:55 thorpej Exp $ */
/*
* Copyright (c) 1997 Jonathan Stone (hereinafter referred to as the author)
@ -2176,6 +2176,77 @@ LEAF(mips3_proc_trampoline)
.set at
END(mips3_proc_trampoline)
/*
* rm52xx_idle:
*
* When no processes are on the runq, cpu_switch branches to
* idle to wait for something to come ready.
*
* NOTE: This is really part of cpu_switch(), but defined here
* for kernel profiling.
*
* This version takes advantage of power-saving features on
* the QED RM52xx family of CPUs.
*/
LEAF(rm52xx_idle)
li t0, (MIPS_INT_MASK | MIPS_SR_INT_IE)
DYNAMIC_STATUS_MASK(t0,t1) # machine dependent masking
mtc0 t0, MIPS_COP_0_STATUS # enable all interrupts
nop
sw zero, _C_LABEL(curproc) # set curproc NULL for stats
#if defined(LOCKDEBUG)
jal _C_LABEL(sched_unlock_idle) # release sched_lock
nop
#endif
/* Try to zero from free pages. */
lw t0, _C_LABEL(uvm) + UVM_PAGE_IDLE_ZERO
nop
beq t0, zero, 1f
nop
jal _C_LABEL(uvm_pageidlezero)
nop
1:
#ifdef MIPS_DYNAMIC_STATUS_MASK
# Do this again since the mask may have changed.
li t3, (MIPS_INT_MASK | MIPS_SR_INT_IE)
DYNAMIC_STATUS_MASK(t3,t1) # machine dependent masking
mtc0 t3, MIPS_COP_0_STATUS # enable all interrupts
nop
#endif
lw t0, _C_LABEL(sched_whichqs) # look for non-empty queue
bne t0, zero, 1f
nop
#define QED_RM52xx_OPCODE_WAIT 0x42000020
.word QED_RM52xx_OPCODE_WAIT
nop
nop
nop
b 1b
nop
1:
#if defined(LOCKDEBUG)
mtc0 zero, MIPS_COP_0_STATUS # disable all interrupts
nop
nop
nop
nop
jal _C_LABEL(sched_lock_idle) # acquire sched_lock
nop
la ra, cpu_switch_queuescan
j ra
nop
#else
mtc0 zero, MIPS_COP_0_STATUS # disable all interrupts
nop
nop
nop
la ra, cpu_switch_queuescan
j ra
nop
#endif
END(rm52xx_idle)
/*
* void mips3_cpu_switch_resume(struct proc *newproc)
*