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Diffstat (limited to 'nuttx/drivers/power/pm_activity.c')
| -rw-r--r-- | nuttx/drivers/power/pm_activity.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/nuttx/drivers/power/pm_activity.c b/nuttx/drivers/power/pm_activity.c new file mode 100644 index 0000000000..8cef46684d --- /dev/null +++ b/nuttx/drivers/power/pm_activity.c @@ -0,0 +1,166 @@ +/**************************************************************************** + * drivers/power/pm_activity.c + * + * Copyright (C) 2011-2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 <nuttx/power/pm.h> +#include <nuttx/clock.h> +#include <arch/irq.h> + +#include "pm_internal.h" + +#ifdef CONFIG_PM + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Public Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: pm_activity + * + * Description: + * This function is called by a device driver to indicate that it is + * performing meaningful activities (non-idle). This increment an activty + * count and/or will restart a idle timer and prevent entering reduced + * power states. + * + * Input Parameters: + * priority - Activity priority, range 0-9. Larger values correspond to + * higher priorities. Higher priority activity can prevent the system + * from entering reduced power states for a longer period of time. + * + * As an example, a button press might be higher priority activity because + * it means that the user is actively interacting with the device. + * + * Returned Value: + * None. + * + * Assumptions: + * This function may be called from an interrupt handler (this is the ONLY + * PM function that may be called from an interrupt handler!). + * + ****************************************************************************/ + +void pm_activity(int priority) +{ + uint32_t now; + uint32_t accum; + irqstate_t flags; + + /* Just increment the activity count in the current time slice. The priority + * is simply the number of counts that are added. + */ + + if (priority > 0) + { + /* Add the priority to the accumulated counts in a critical section. */ + + flags = irqsave(); + accum = (uint32_t)g_pmglobals.accum + priority; + + /* Make sure that we do not overflow the underlying uint16_t representation */ + + if (accum > INT16_MAX) + { + accum = INT16_MAX; + } + + /* Save the updated count */ + + g_pmglobals.accum = (int16_t)accum; + + /* Check the elapsed time. In periods of low activity, time slicing is + * controlled by IDLE loop polling; in periods of higher activity, time + * slicing is controlled by driver activity. In either case, the duration + * of the time slice is only approximate; during times of heavy activity, + * time slices may be become longer and the activity level may be over- + * estimated. + */ + + now = clock_systimer(); + if (now - g_pmglobals.stime >= TIME_SLICE_TICKS) + { + int16_t tmp; + + /* Sample the count, reset the time and count, and assess the PM + * state. This is an atomic operation because interrupts are + * still disabled. + */ + + tmp = g_pmglobals.accum; + g_pmglobals.stime = now; + g_pmglobals.accum = 0; + + /* Reassessing the PM state may require some computation. However, + * the work will actually be performed on a worker thread at a user- + * controlled priority. + */ + + (void)pm_update(accum); + } + + irqrestore(flags); + } +} + +#endif /* CONFIG_PM */
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