a3e7abc2e2
- pm_off() should prevent other threads from getting executed after it is
called, as it should turn off the MCU completely according to its doc
- Previously, the fallback implementation would still allow other threads
to continue working
- Simply disabling IRQs and never enabling them again should make sure
the MCU behaves like it would be completely off
- pm_off() should reduce the power consumption as much as possible
- Previously, when IRQs came after the call to pm_set_lowest() in the
fallback implementation of pm_off(), `while(1) {}` got executed at full
power consumption
- Just calling `pm_set(0);` in a loop while make sure that lowest power mode
is restored if the MCU wakes up again.
- The check if the lowest power mode is available is skipped, as no code
gets executed afterwards anyway
91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/*
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* Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup sys_pm_layered
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* @{
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*
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* @file
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* @brief Platform-independent power management code
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*
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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*
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* @}
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*/
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#include "irq.h"
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#include "periph/pm.h"
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#include "pm_layered.h"
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#define ENABLE_DEBUG (0)
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#include "debug.h"
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#ifndef PM_NUM_MODES
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#error PM_NUM_MODES must be defined in periph_cpu.h!
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#endif
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#ifndef PM_BLOCKER_INITIAL
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#define PM_BLOCKER_INITIAL 0x01010101 /* block all by default */
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#endif
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/**
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* @brief Global variable for keeping track of blocked modes
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*/
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volatile pm_blocker_t pm_blocker = { .val_u32 = PM_BLOCKER_INITIAL };
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void pm_set_lowest(void)
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{
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pm_blocker_t blocker = pm_blocker;
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unsigned mode = PM_NUM_MODES;
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while (mode) {
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if (blocker.val_u8[mode-1]) {
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break;
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}
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mode--;
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}
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/* set lowest mode if blocker is still the same */
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unsigned state = irq_disable();
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if (blocker.val_u32 == pm_blocker.val_u32) {
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DEBUG("pm: setting mode %u\n", mode);
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pm_set(mode);
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}
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else {
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DEBUG("pm: mode block changed\n");
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}
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irq_restore(state);
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}
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void pm_block(unsigned mode)
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{
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assert(pm_blocker.val_u8[mode] != 255);
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unsigned state = irq_disable();
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pm_blocker.val_u8[mode]++;
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irq_restore(state);
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}
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void pm_unblock(unsigned mode)
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{
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assert(pm_blocker.val_u8[mode] > 0);
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unsigned state = irq_disable();
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pm_blocker.val_u8[mode]--;
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irq_restore(state);
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}
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#ifndef PROVIDES_PM_LAYERED_OFF
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void pm_off(void)
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{
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irq_disable();
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while(1) {
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pm_set(0);
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}
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}
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#endif
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