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Diffstat (limited to 'nuttx/drivers/power/pm_update.c')
-rw-r--r-- | nuttx/drivers/power/pm_update.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/nuttx/drivers/power/pm_update.c b/nuttx/drivers/power/pm_update.c new file mode 100644 index 000000000..ae5e1f840 --- /dev/null +++ b/nuttx/drivers/power/pm_update.c @@ -0,0 +1,334 @@ +/**************************************************************************** + * drivers/power/pm_update.c + * + * 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <assert.h> + +#include <nuttx/power/pm.h> +#include <nuttx/wqueue.h> + +#include "pm_internal.h" + +#ifdef CONFIG_PM + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ +/* CONFIG_PM_MEMORY is the total number of time slices (including the current + * time slice. The histor or previous values is then CONFIG_PM_MEMORY-1. + */ + +#if CONFIG_PM_MEMORY > 1 +static const int16_t g_pmcoeffs[CONFIG_PM_MEMORY-1] = +{ + CONFIG_PM_COEF1 +#if CONFIG_PM_MEMORY > 2 + , CONFIG_PM_COEF2 +#endif +#if CONFIG_PM_MEMORY > 3 + , CONFIG_PM_COEF3 +#endif +#if CONFIG_PM_MEMORY > 4 + , CONFIG_PM_COEF4 +#endif +#if CONFIG_PM_MEMORY > 5 + , CONFIG_PM_COEF5 +#endif +#if CONFIG_PM_MEMORY > 6 +# warning "This logic needs to be extended" +#endif +}; +#endif + +/* Threshold activity values to enter into the next lower power consumption + * state. Indexing is next state 0:IDLE, 1:STANDBY, 2:SLEEP. + */ + +static const int16_t g_pmenterthresh[3] = +{ + CONFIG_PM_IDLEENTER_THRESH, + CONFIG_PM_STANDBYENTER_THRESH, + CONFIG_PM_SLEEPENTER_THRESH +}; + +/* Threshold activity values to leave the current low power consdumption + * state. Indexing is current state 0:IDLE, 1: STANDBY, 2: SLEEP. + */ + +static const int16_t g_pmexitthresh[3] = +{ + CONFIG_PM_IDLEEXIT_THRESH, + CONFIG_PM_STANDBYEXIT_THRESH, + CONFIG_PM_SLEEPEXIT_THRESH +}; + +/* Threshold time slice count to enter the next low power consdumption + * state. Indexing is next state 0:IDLE, 1: STANDBY, 2: SLEEP. + */ + +static const uint16_t g_pmcount[3] = +{ + CONFIG_PM_IDLEENTER_COUNT, + CONFIG_PM_STANDBYENTER_COUNT, + CONFIG_PM_SLEEPENTER_COUNT +}; + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: pm_worker + * + * Description: + * This worker function is queue at the end of a time slice in order to + * update driver activity metrics and recommended states. + * + * Input Parameters: + * arg - The value of the activity accumulator at the end of the time + * slice. + * + * Returned Value: + * None. + * + * Assumptions: + * This function runs on the worker thread. + * + ****************************************************************************/ + +void pm_worker(FAR void *arg) +{ + int16_t accum = (int16_t)((intptr_t)arg); + int32_t Y; + int index; + +#if CONFIG_PM_MEMORY > 1 + int32_t denom; + int i, j; + + /* We won't bother to do anything until we have accumulated + * CONFIG_PM_MEMORY-1 samples. + */ + + if (g_pmglobals.mcnt < CONFIG_PM_MEMORY-1) + { + g_pmglobals.memory[g_pmglobals.mcnt] = accum; + g_pmglobals.mcnt++; + return; + } + + /* 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 + * + * First, calclate Y = An*X + */ + + Y = CONFIG_PM_COEFN * accum; + denom = CONFIG_PM_COEFN; + + /* Then calculate Y += SUM(Ai*Yi), i = 1..n-1. The oldest sample will + * reside at g_pmglobals.mndx (and this is the value that we will overwrite + * with the new value). + */ + + for (i = 0, j = g_pmglobals.mndx; i < CONFIG_PM_MEMORY-1; i++, j++) + { + if (j >= CONFIG_PM_MEMORY-1) + { + j = 0; + } + + Y += g_pmcoeffs[i] * g_pmglobals.memory[j]; + denom += g_pmcoeffs[i]; + } + + /* Compute and save the new activity value */ + + Y /= denom; + g_pmglobals.memory[g_pmglobals.mndx] = Y; + g_pmglobals.mndx++; + if (g_pmglobals.mndx >= CONFIG_PM_MEMORY-1) + { + g_pmglobals.mndx = 0; + } + +#else + + /* No smoothing */ + + Y = accum; + +#endif + + /* First check if increased activity should cause us to return to the + * normal operating state. This would be unlikely for the lowest power + * consumption states because the CPU is probably asleep. However this + * probably does apply for the IDLE state. + */ + + if (g_pmglobals.state > PM_NORMAL) + { + /* Get the table index for the current state (which will be the + * current state minus one) + */ + + index = g_pmglobals.state - 1; + + /* Has the threshold to return to normal power consumption state been + * exceeded? + */ + + if (Y > g_pmexitthresh[index]) + { + /* Yes... reset the count and recommend the normal state. */ + + g_pmglobals.thrcnt = 0; + g_pmglobals.recommended = PM_NORMAL; + return; + } + } + + /* Now, compare this new activity level to the thresholds and counts for + * the next lower power consumption state. If we are already in the SLEEP + * state, then there is nothing more to be done (in fact, I would be + * surprised to be executing!). + */ + + if (g_pmglobals.state < PM_SLEEP) + { + unsigned int nextstate; + + /* Get the next state and the table index for the next state (which will + * be the current state) + */ + + index = g_pmglobals.state; + nextstate = g_pmglobals.state + 1; + + /* Has the threshold to enter the next lower power consumption state + * been exceeded? + */ + + if (Y > g_pmenterthresh[index]) + { + /* No... reset the count and recommend the current state */ + + g_pmglobals.thrcnt = 0; + g_pmglobals.recommended = g_pmglobals.state; + } + + /* Yes.. have we already recommended this state? If so, do nothing */ + + else if (g_pmglobals.recommended < nextstate) + { + /* No.. increment the count. Has is passed the the count required + * for a state transition? + */ + + if (++g_pmglobals.thrcnt >= g_pmcount[index]) + { + /* Yes, recommend the new state and set up for the next + * transition. + */ + + g_pmglobals.thrcnt = 0; + g_pmglobals.recommended = nextstate; + } + } + } +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * 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. This will + * also serialize all of the updates and eliminate any need for additional + * protection. + * + ****************************************************************************/ + +void pm_update(int16_t accum) +{ + /* The work will be performed on the worker thread */ + + DEBUGASSERT(g_pmglobals.work.worker == NULL); + (void)work_queue(&g_pmglobals.work, pm_worker, (FAR void*)((intptr_t)accum), 0); +} + +#endif /* CONFIG_PM */
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