5fa0189cee
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4321 42af7a65-404d-4744-a932-0658087f49c3
334 lines
10 KiB
C
334 lines
10 KiB
C
/****************************************************************************
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* drivers/power/pm_update.c
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*
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* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <nuttx/power/pm.h>
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#include <nuttx/wqueue.h>
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#include "pm_internal.h"
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#ifdef CONFIG_PM
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* CONFIG_PM_MEMORY is the total number of time slices (including the current
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* time slice. The histor or previous values is then CONFIG_PM_MEMORY-1.
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*/
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#if CONFIG_PM_MEMORY > 1
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static const int16_t g_pmcoeffs[CONFIG_PM_MEMORY-1] =
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{
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CONFIG_PM_COEF1
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#if CONFIG_PM_MEMORY > 2
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, CONFIG_PM_COEF2
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#endif
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#if CONFIG_PM_MEMORY > 3
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, CONFIG_PM_COEF3
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#endif
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#if CONFIG_PM_MEMORY > 4
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, CONFIG_PM_COEF4
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#endif
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#if CONFIG_PM_MEMORY > 5
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, CONFIG_PM_COEF5
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#endif
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#if CONFIG_PM_MEMORY > 6
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# warning "This logic needs to be extended"
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#endif
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};
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#endif
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/* Threshold activity values to enter into the next lower power consumption
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* state. Indexing is next state 0:IDLE, 1:STANDBY, 2:SLEEP.
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*/
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static const int16_t g_pmenterthresh[3] =
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{
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CONFIG_PM_IDLEENTER_THRESH,
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CONFIG_PM_STANDBYENTER_THRESH,
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CONFIG_PM_SLEEPENTER_THRESH
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};
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/* Threshold activity values to leave the current low power consdumption
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* state. Indexing is current state 0:IDLE, 1: STANDBY, 2: SLEEP.
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*/
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static const int16_t g_pmexitthresh[3] =
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{
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CONFIG_PM_IDLEEXIT_THRESH,
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CONFIG_PM_STANDBYEXIT_THRESH,
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CONFIG_PM_SLEEPEXIT_THRESH
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};
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/* Threshold time slice count to enter the next low power consdumption
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* state. Indexing is next state 0:IDLE, 1: STANDBY, 2: SLEEP.
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*/
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static const uint16_t g_pmcount[3] =
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{
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CONFIG_PM_IDLEENTER_COUNT,
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CONFIG_PM_STANDBYENTER_COUNT,
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CONFIG_PM_SLEEPENTER_COUNT
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pm_worker
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*
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* Description:
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* This worker function is queue at the end of a time slice in order to
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* update driver activity metrics and recommended states.
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*
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* Input Parameters:
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* arg - The value of the activity accumulator at the end of the time
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* slice.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* This function runs on the worker thread.
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*
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****************************************************************************/
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void pm_worker(FAR void *arg)
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{
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int16_t accum = (int16_t)((intptr_t)arg);
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int32_t Y;
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int index;
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#if CONFIG_PM_MEMORY > 1
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int32_t denom;
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int i, j;
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/* We won't bother to do anything until we have accumulated
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* CONFIG_PM_MEMORY-1 samples.
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*/
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if (g_pmglobals.mcnt < CONFIG_PM_MEMORY-1)
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{
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g_pmglobals.memory[g_pmglobals.mcnt] = accum;
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g_pmglobals.mcnt++;
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return;
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}
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/* The averaging algorithm is simply: Y = (An*X + SUM(Ai*Yi))/SUM(Aj), where
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* i = 1..n-1 and j= 1..n, n is the length of the "memory", Ai is the
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* weight applied to each value, and X is the current activity.
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*
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* CONFIG_PM_MEMORY provides the memory for the algorithm. Default: 2
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* CONFIG_PM_COEFn provides weight for each sample. Default: 1
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*
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* First, calclate Y = An*X
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*/
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Y = CONFIG_PM_COEFN * accum;
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denom = CONFIG_PM_COEFN;
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/* Then calculate Y += SUM(Ai*Yi), i = 1..n-1. The oldest sample will
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* reside at g_pmglobals.mndx (and this is the value that we will overwrite
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* with the new value).
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*/
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for (i = 0, j = g_pmglobals.mndx; i < CONFIG_PM_MEMORY-1; i++, j++)
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{
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if (j >= CONFIG_PM_MEMORY-1)
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{
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j = 0;
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}
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Y += g_pmcoeffs[i] * g_pmglobals.memory[j];
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denom += g_pmcoeffs[i];
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}
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/* Compute and save the new activity value */
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Y /= denom;
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g_pmglobals.memory[g_pmglobals.mndx] = Y;
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g_pmglobals.mndx++;
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if (g_pmglobals.mndx >= CONFIG_PM_MEMORY-1)
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{
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g_pmglobals.mndx = 0;
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}
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#else
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/* No smoothing */
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Y = accum;
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#endif
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/* First check if increased activity should cause us to return to the
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* normal operating state. This would be unlikely for the lowest power
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* consumption states because the CPU is probably asleep. However this
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* probably does apply for the IDLE state.
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*/
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if (g_pmglobals.state > PM_NORMAL)
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{
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/* Get the table index for the current state (which will be the
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* current state minus one)
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*/
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index = g_pmglobals.state - 1;
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/* Has the threshold to return to normal power consumption state been
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* exceeded?
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*/
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if (Y > g_pmexitthresh[index])
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{
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/* Yes... reset the count and recommend the normal state. */
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g_pmglobals.thrcnt = 0;
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g_pmglobals.recommended = PM_NORMAL;
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return;
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}
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}
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/* Now, compare this new activity level to the thresholds and counts for
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* the next lower power consumption state. If we are already in the SLEEP
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* state, then there is nothing more to be done (in fact, I would be
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* surprised to be executing!).
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*/
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if (g_pmglobals.state < PM_SLEEP)
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{
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unsigned int nextstate;
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/* Get the next state and the table index for the next state (which will
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* be the current state)
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*/
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index = g_pmglobals.state;
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nextstate = g_pmglobals.state + 1;
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/* Has the threshold to enter the next lower power consumption state
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* been exceeded?
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*/
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if (Y > g_pmenterthresh[index])
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{
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/* No... reset the count and recommend the current state */
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g_pmglobals.thrcnt = 0;
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g_pmglobals.recommended = g_pmglobals.state;
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}
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/* Yes.. have we already recommended this state? If so, do nothing */
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else if (g_pmglobals.recommended < nextstate)
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{
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/* No.. increment the count. Has is passed the the count required
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* for a state transition?
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*/
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if (++g_pmglobals.thrcnt >= g_pmcount[index])
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{
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/* Yes, recommend the new state and set up for the next
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* transition.
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*/
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g_pmglobals.thrcnt = 0;
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g_pmglobals.recommended = nextstate;
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}
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}
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}
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pm_update
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*
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* Description:
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* This internal function is called at the end of a time slice in order to
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* update driver activity metrics and recommended states.
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*
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* Input Parameters:
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* accum - The value of the activity accumulator at the end of the time
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* slice.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* This function may be called from a driver, perhaps even at the interrupt
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* level. It may also be called from the IDLE loop at the lowest possible
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* priority level. To reconcile these various conditions, all work is
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* performed on the worker thread at a user-selectable priority. This will
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* also serialize all of the updates and eliminate any need for additional
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* protection.
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*
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****************************************************************************/
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void pm_update(int16_t accum)
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{
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/* The work will be performed on the worker thread */
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DEBUGASSERT(g_pmglobals.work.worker == NULL);
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(void)work_queue(&g_pmglobals.work, pm_worker, (FAR void*)((intptr_t)accum), 0);
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}
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#endif /* CONFIG_PM */ |