diff options
Diffstat (limited to 'nuttx/drivers/power/pm_changestate.c')
-rw-r--r-- | nuttx/drivers/power/pm_changestate.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/nuttx/drivers/power/pm_changestate.c b/nuttx/drivers/power/pm_changestate.c new file mode 100644 index 000000000..f64760f55 --- /dev/null +++ b/nuttx/drivers/power/pm_changestate.c @@ -0,0 +1,227 @@ +/**************************************************************************** + * drivers/power/pm_changestate.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 <nuttx/power/pm.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 + ****************************************************************************/ + +/**************************************************************************** + * Name: pm_prepall + * + * Description: + * Prepare every driver for the state change. + * + * Input Parameters: + * newstate - Identifies the new PM state + * + * Returned Value: + * 0 (OK) means that the callback function for all registered drivers + * returned OK (meaning that they accept the state change). Non-zero + * means that one of the drivers refused the state change. In this case, + * the system will revert to the preceding state. + * + * Assumptions: + * Interrupts are disabled. + * + ****************************************************************************/ + +static int pm_prepall(enum pm_state_e newstate) +{ + FAR sq_entry_t *entry; + int ret = OK; + + /* Visit each registered callback structure. */ + + for (entry = sq_peek(&g_pmglobals.registry); + entry && ret == OK; + entry = sq_next(entry)) + { + /* Is the prepare callback supported? */ + + FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry; + if (cb->prepare) + { + /* Yes.. prepare the driver */ + + ret = cb->prepare(cb, newstate); + } + } + + return ret; +} + +/**************************************************************************** + * Name: pm_changeall + * + * Description: + * Inform all drivers of the state change. + * + * Input Parameters: + * newstate - Identifies the new PM state + * + * Returned Value: + * None + * + * Assumptions: + * Interrupts are disabled. + * + ****************************************************************************/ + +static inline void pm_changeall(enum pm_state_e newstate) +{ + FAR sq_entry_t *entry; + + /* Visit each registered callback structure. */ + + for (entry = sq_peek(&g_pmglobals.registry); entry; entry = sq_next(entry)) + { + /* Is the notification callback supported? */ + + FAR struct pm_callback_s *cb = (FAR struct pm_callback_s *)entry; + if (cb->notify) + { + /* Yes.. notify the driver */ + + cb->notify(cb, newstate); + } + } +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: pm_changestate + * + * Description: + * This function is used by platform-specific power management logic. It + * will announce the power management power management state change to all + * drivers that have registered for power management event callbacks. + * + * Input Parameters: + * newstate - Identifies the new PM state + * + * Returned Value: + * 0 (OK) means that the callback function for all registered drivers + * returned OK (meaning that they accept the state change). Non-zero + * means that one of the drivers refused the state change. In this case, + * the system will revert to the preceding state. + * + * Assumptions: + * It is assumed that interrupts are disabled when this function is + * called. This function is probably called from the IDLE loop... the + * lowest priority task in the system. Changing driver power management + * states may result in renewed system activity and, as a result, can + * suspend the IDLE thread before it completes the entire state change + * unless interrupts are disabled throughout the state change. + * + ****************************************************************************/ + +int pm_changestate(enum pm_state_e newstate) +{ + irqstate_t flags; + int ret; + + /* Disable interrupts throught this operation... changing driver states + * could cause additional driver activity that might interfere with the + * state change. When the state change is complete, interrupts will be + * re-enabled. + */ + + flags = irqsave(); + + /* First, prepare the drivers for the state change. In this phase, + * drivers may refuse the state state change. + */ + + ret = pm_prepall(newstate); + if (ret != OK) + { + /* One or more drivers is not ready for this state change. Revert to + * the preceding state. + */ + + newstate = g_pmglobals.state; + (void)pm_prepall(newstate); + } + + /* All drivers have agreed to the state change (or, one or more have + * disagreed and the state has been reverted). Set the new state. + */ + + pm_changeall(newstate); + g_pmglobals.state = newstate; + + /* Restore the interrupt state */ + + irqrestore(flags); + return ret; +} + +#endif /* CONFIG_PM */ |