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334 lines
10 KiB
334 lines
10 KiB
/**************************************************************************** |
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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 */ |