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/****************************************************************************
* drivers/power/pm_internal.h
*
* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __DRIVERS_POWER_PM_INTERNAL_H
#define __DRIVERS_POWER_PM_INTERNAL_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <semaphore.h>
#include <queue.h>
#include <nuttx/power/pm.h>
#include <nuttx/wqueue.h>
#ifdef CONFIG_PM
/****************************************************************************
* Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_SCHED_WORKQUEUE
# warning "Worker thread support is required (CONFIG_SCHED_WORKQUEUE)"
#endif
/* Convert the time slice interval into system clock ticks.
*
* CONFIG_PM_SLICEMS provides the duration of one time slice in milliseconds.
* CLOCKS_PER_SEC provides the number of timer ticks in one second.
*
* slice ticks = (CONFIG_PM_SLICEMS msec / 1000 msec/sec) /
* (CLOCKS_PER_SEC ticks/sec)
*/
#define TIME_SLICE_TICKS ((CONFIG_PM_SLICEMS * CLOCKS_PER_SEC) / 1000)
/* Function-like macros *****************************************************/
/****************************************************************************
* Name: pm_lock
*
* Descripton:
* Lock the power management registry. NOTE: This function may return
* an error if a signal is received while what (errno == EINTR).
*
****************************************************************************/
#define pm_lock() sem_wait(&g_pmglobals.regsem);
/****************************************************************************
* Name: pm_unlock
*
* Descripton:
* Unlock the power management registry.
*
****************************************************************************/
#define pm_unlock() sem_post(&g_pmglobals.regsem);
/****************************************************************************
* Public Types
****************************************************************************/
/* This structure encapsulates all of the global data used by the PM module */
struct pm_global_s
{
/* state - The current state (as determined by an explicit call to
* pm_changestate()
* recommended - The recommended state based on the PM algorithm in
* function pm_update().
* mndex - The index to the next slot in the memory[] array to use.
* mcnt - A tiny counter used only at start up. The actual
* algorithm cannot be applied until CONFIG_PM_MEMORY
* samples have been collected.
*/
uint8_t state;
uint8_t recommended;
uint8_t mndx;
uint8_t mcnt;
/* accum - The accumulated counts in this time interval
* thrcnt - The number of below threshold counts seen.
*/
int16_t accum;
uint16_t thrcnt;
/* This is the averaging "memory." The averaging algorithm is simply:
* Y = (An*X + SUM(Ai*Yi))/SUM(Aj), where i = 1..n-1 and j= 1..n, n is the
* length of the "memory", Ai is the weight applied to each value, and X is
* the current activity.
*
* CONFIG_PM_MEMORY provides the memory for the algorithm. Default: 2
* CONFIG_PM_COEFn provides weight for each sample. Default: 1
*/
#if CONFIG_PM_MEMORY > 1
int16_t memory[CONFIG_PM_MEMORY-1];
#endif
/* stime - The time (in ticks) at the start of the current time slice */
uint32_t stime;
/* This semaphore manages mutually exclusive access to the power management
* registry. It must be initialized to the value 1.
*/
sem_t regsem;
/* For work that has been deferred to the worker thread */
struct work_s work;
/* registry is a singly-linked list of registered power management
* callback structures. To ensure mutually exclusive access, this list
* must be locked by calling pm_lock() before it is accessed.
*/
sq_queue_t registry;
};
/****************************************************************************
* Public Data
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
# define EXTERN extern "C"
extern "C"
{
#else
# define EXTERN extern
#endif
/* All PM global data: */
EXTERN struct pm_global_s g_pmglobals;
/************************************************************************************
* Public Function Prototypes
************************************************************************************/
/****************************************************************************
* Name: pm_update
*
* Description:
* This internal function is called at the end of a time slice in order to
* update driver activity metrics and recommended states.
*
* Input Parameters:
* accum - The value of the activity accumulator at the end of the time
* slice.
*
* Returned Value:
* None.
*
* Assumptions:
* This function may be called from a driver, perhaps even at the interrupt
* level. It may also be called from the IDLE loop at the lowest possible
* priority level. To reconcile these various conditions, all work is
* performed on the worker thread at a user-selectable priority.
*
****************************************************************************/
EXTERN void pm_update(int16_t accum);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* CONFIG_PM */
#endif /* #define __DRIVERS_POWER_PM_INTERNAL_H */
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