fbb82b0365
This provides a machine_ops-based reboot interface loosely cloned from x86, and converts the native sh32 and sh64 cases over to it. Necessary both for tying in SMP support and also enabling platforms like SDK7786 to add support for their microcontroller-based power managers. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
157 lines
3.2 KiB
C
157 lines
3.2 KiB
C
/*
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* The idle loop for all SuperH platforms.
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*
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* Copyright (C) 2002 - 2009 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/pm.h>
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#include <linux/tick.h>
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#include <linux/preempt.h>
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#include <linux/thread_info.h>
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#include <linux/irqflags.h>
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#include <linux/smp.h>
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#include <asm/pgalloc.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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void (*pm_idle)(void) = NULL;
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static int hlt_counter;
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static int __init nohlt_setup(char *__unused)
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{
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hlt_counter = 1;
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return 1;
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}
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__setup("nohlt", nohlt_setup);
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static int __init hlt_setup(char *__unused)
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{
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hlt_counter = 0;
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return 1;
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}
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__setup("hlt", hlt_setup);
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static inline int hlt_works(void)
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{
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return !hlt_counter;
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}
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/*
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* On SMP it's slightly faster (but much more power-consuming!)
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* to poll the ->work.need_resched flag instead of waiting for the
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* cross-CPU IPI to arrive. Use this option with caution.
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*/
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static void poll_idle(void)
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{
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local_irq_enable();
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while (!need_resched())
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cpu_relax();
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}
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void default_idle(void)
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{
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if (hlt_works()) {
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb__after_clear_bit();
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set_bl_bit();
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if (!need_resched()) {
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local_irq_enable();
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cpu_sleep();
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} else
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local_irq_enable();
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set_thread_flag(TIF_POLLING_NRFLAG);
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clear_bl_bit();
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} else
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poll_idle();
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}
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/*
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* The idle thread. There's no useful work to be done, so just try to conserve
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* power and have a low exit latency (ie sit in a loop waiting for somebody to
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* say that they'd like to reschedule)
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*/
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void cpu_idle(void)
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{
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unsigned int cpu = smp_processor_id();
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set_thread_flag(TIF_POLLING_NRFLAG);
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/* endless idle loop with no priority at all */
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while (1) {
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tick_nohz_stop_sched_tick(1);
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while (!need_resched() && cpu_online(cpu)) {
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check_pgt_cache();
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rmb();
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local_irq_disable();
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/* Don't trace irqs off for idle */
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stop_critical_timings();
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pm_idle();
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/*
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* Sanity check to ensure that pm_idle() returns
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* with IRQs enabled
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*/
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WARN_ON(irqs_disabled());
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start_critical_timings();
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}
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tick_nohz_restart_sched_tick();
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preempt_enable_no_resched();
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schedule();
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preempt_disable();
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}
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}
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void __cpuinit select_idle_routine(void)
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{
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/*
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* If a platform has set its own idle routine, leave it alone.
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*/
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if (pm_idle)
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return;
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if (hlt_works())
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pm_idle = default_idle;
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else
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pm_idle = poll_idle;
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}
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static void do_nothing(void *unused)
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{
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}
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void stop_this_cpu(void *unused)
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{
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local_irq_disable();
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cpu_clear(smp_processor_id(), cpu_online_map);
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for (;;)
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cpu_sleep();
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}
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/*
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* cpu_idle_wait - Used to ensure that all the CPUs discard old value of
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* pm_idle and update to new pm_idle value. Required while changing pm_idle
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* handler on SMP systems.
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*
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* Caller must have changed pm_idle to the new value before the call. Old
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* pm_idle value will not be used by any CPU after the return of this function.
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*/
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void cpu_idle_wait(void)
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{
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smp_mb();
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/* kick all the CPUs so that they exit out of pm_idle */
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smp_call_function(do_nothing, NULL, 1);
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}
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EXPORT_SYMBOL_GPL(cpu_idle_wait);
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