nuttx/drivers/power/pm/pm_changestate.c

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/****************************************************************************
* drivers/power/pm/pm_changestate.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
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#include <assert.h>
#include <stdlib.h>
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#include <nuttx/power/pm.h>
#include <nuttx/irq.h>
#include <nuttx/queue.h>
#include "pm.h"
#ifdef CONFIG_PM
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pm_prepall
*
* Description:
* Prepare every driver for the state change.
*
* Input Parameters:
* domain - Identifies the domain of the new PM state
* newstate - Identifies the new PM state
*
* Returned Value:
* 0 (OK) means that the callback function for all registered drivers
* returned OK (meaning that they accept the state change). Non-zero
* means that one of the drivers refused the state change. In this case,
* the system will revert to the preceding state.
*
* Assumptions:
* Interrupts are disabled.
*
****************************************************************************/
static int pm_prepall(int domain, enum pm_state_e newstate)
{
FAR dq_entry_t *entry;
int ret = OK;
if (newstate <= g_pmglobals.domain[domain].state)
{
/* Visit each registered callback structure in normal order. */
for (entry = dq_peek(&g_pmglobals.registry);
entry && ret == OK;
entry = dq_next(entry))
{
/* Is the prepare callback supported? */
FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry;
if (cb->prepare)
{
/* Yes.. prepare the driver */
ret = cb->prepare(cb, domain, newstate);
}
}
}
else
{
/* Visit each registered callback structure in reverse order. */
for (entry = dq_tail(&g_pmglobals.registry);
entry && ret == OK;
entry = dq_prev(entry))
{
/* Is the prepare callback supported? */
FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry;
if (cb->prepare)
{
/* Yes.. prepare the driver */
ret = cb->prepare(cb, domain, newstate);
}
}
}
return ret;
}
/****************************************************************************
* Name: pm_changeall
*
* Description:
* domain - Identifies the domain of the new PM state
* Inform all drivers of the state change.
*
* Input Parameters:
* domain - Identifies the domain of the new PM state
* newstate - Identifies the new PM state
*
* Returned Value:
* None
*
* Assumptions:
* Interrupts are disabled.
*
****************************************************************************/
static inline void pm_changeall(int domain, enum pm_state_e newstate)
{
FAR dq_entry_t *entry;
if (newstate <= g_pmglobals.domain[domain].state)
{
/* Visit each registered callback structure in normal order. */
for (entry = dq_peek(&g_pmglobals.registry);
entry; entry = dq_next(entry))
{
/* Is the notification callback supported? */
FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry;
if (cb->notify)
{
/* Yes.. notify the driver */
cb->notify(cb, domain, newstate);
}
}
}
else
{
/* Visit each registered callback structure in reverse order. */
for (entry = dq_tail(&g_pmglobals.registry);
entry; entry = dq_prev(entry))
{
/* Is the notification callback supported? */
FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry;
if (cb->notify)
{
/* Yes.. notify the driver */
cb->notify(cb, domain, newstate);
}
}
}
}
#ifdef CONFIG_PM_PROCFS
static void pm_stats(FAR struct pm_domain_s *dom, int curstate, int newstate)
{
struct timespec ts;
clock_systime_timespec(&ts);
clock_timespec_subtract(&ts, &dom->start, &ts);
if (newstate == PM_RESTORE)
{
/* Wakeup from WFI */
clock_timespec_add(&ts, &dom->sleep[curstate], &dom->sleep[curstate]);
}
else
{
/* Sleep to WFI */
clock_timespec_add(&ts, &dom->wake[curstate], &dom->wake[curstate]);
}
/* Update start */
clock_systime_timespec(&dom->start);
}
#else
# define pm_stats(dom, curstate, newstate)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pm_changestate
*
* Description:
* This function is used by platform-specific power management logic. It
* will announce the power management power management state change to all
* drivers that have registered for power management event callbacks.
*
* Input Parameters:
* domain - Identifies the domain of the new PM state
* newstate - Identifies the new PM state
*
* Returned Value:
* 0 (OK) means that the callback function for all registered drivers
* returned OK (meaning that they accept the state change). Non-zero
* means that one of the drivers refused the state change. In this case,
* the system will revert to the preceding state.
*
* Assumptions:
* It is assumed that interrupts are disabled when this function is
* called. This function is probably called from the IDLE loop... the
* lowest priority task in the system. Changing driver power management
* states may result in renewed system activity and, as a result, can
* suspend the IDLE thread before it completes the entire state change
* unless interrupts are disabled throughout the state change.
*
****************************************************************************/
int pm_changestate(int domain, enum pm_state_e newstate)
{
irqstate_t flags;
int ret = OK;
DEBUGASSERT(domain >= 0 && domain < CONFIG_PM_NDOMAINS);
/* Disable interrupts throughout this operation... changing driver states
* could cause additional driver activity that might interfere with the
* state change. When the state change is complete, interrupts will be
* re-enabled.
*/
flags = pm_domain_lock(domain);
if (newstate != PM_RESTORE)
{
/* First, prepare the drivers for the state change. In this phase,
* drivers may refuse the state state change.
*/
ret = pm_prepall(domain, newstate);
if (ret != OK)
{
/* One or more drivers is not ready for this state change.
* Revert to the preceding state.
*/
newstate = g_pmglobals.domain[domain].state;
pm_prepall(domain, newstate);
}
}
/* Statistics */
pm_stats(&g_pmglobals.domain[domain],
g_pmglobals.domain[domain].state, newstate);
/* All drivers have agreed to the state change (or, one or more have
* disagreed and the state has been reverted). Set the new state.
*/
pm_changeall(domain, newstate);
if (newstate != PM_RESTORE)
{
g_pmglobals.domain[domain].state = newstate;
}
/* Notify governor of (possible) state change */
if (g_pmglobals.domain[domain].governor->statechanged)
{
g_pmglobals.domain[domain].governor->statechanged(domain, newstate);
}
/* Restore the interrupt state */
pm_domain_unlock(domain, flags);
return ret;
}
/****************************************************************************
* Name: pm_querystate
*
* Description:
* This function returns the current power management state.
*
* Input Parameters:
* domain - The PM domain to check
*
* Returned Value:
* The current power management state.
*
****************************************************************************/
enum pm_state_e pm_querystate(int domain)
{
DEBUGASSERT(domain >= 0 && domain < CONFIG_PM_NDOMAINS);
return g_pmglobals.domain[domain].state;
}
#endif /* CONFIG_PM */