/**************************************************************************** * drivers/power/pm * * Copyright (C) 2011-2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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_H #define __DRIVERS_POWER_PM_H /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #ifdef CONFIG_PM /**************************************************************************** * Pre-processor 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_H */