162 lines
5.4 KiB
C
162 lines
5.4 KiB
C
/************************************************************
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* up_unblocktask.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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 Gregory Nutt 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 <sys/types.h>
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#include <sched.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include "os_internal.h"
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#include "up_internal.h"
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/************************************************************
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* Private Definitions
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************************************************************/
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/************************************************************
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* Private Data
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************************************************************/
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/************************************************************
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* Private Funtions
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************************************************************/
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/************************************************************
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* Public Funtions
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************************************************************/
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/************************************************************
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* Name: up_unblock_task
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*
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* Description:
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* A task is currently in an inactive task list
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* but has been prepped to execute. Move the TCB to the
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* ready-to-run list, restore its context, and start execution.
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*
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* Inputs:
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* tcb: Refers to the tcb to be unblocked. This tcb is
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* in one of the waiting tasks lists. It must be moved to
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* the ready-to-run list and, if it is the highest priority
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* ready to run taks, executed.
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*
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************************************************************/
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void up_unblock_task(FAR _TCB *tcb)
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{
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/* Verify that the context switch can be performed */
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if ((tcb->task_state < FIRST_BLOCKED_STATE) ||
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(tcb->task_state > LAST_BLOCKED_STATE))
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{
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PANIC(OSERR_BADUNBLOCKSTATE);
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}
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else
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{
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FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
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dbg("Unblocking TCB=%p\n", tcb);
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/* Remove the task from the blocked task list */
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sched_removeblocked(tcb);
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/* Reset its timeslice. This is only meaningful for round
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* robin tasks but it doesn't here to do it for everything
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*/
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#if CONFIG_RR_INTERVAL > 0
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tcb->timeslice = CONFIG_RR_INTERVAL;
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#endif
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/* Add the task in the correct location in the prioritized
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* g_readytorun task list
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*/
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if (sched_addreadytorun(tcb))
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{
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/* The currently active task has changed! We need to do
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* a context switch to the new task.
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*
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* Are we in an interrupt handler?
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*/
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if (g_irqtos)
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{
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/* Yes, then we have to do things differently.
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* Just copy the current stack into the OLD rtcb.
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*/
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up_savestack(&rtcb->xcp);
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/* Restore the exception context of the rtcb at the (new) head
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* of the g_readytorun task list.
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*/
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rtcb = (FAR _TCB*)g_readytorun.head;
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dbg("New Active Task TCB=%p\n", rtcb);
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/* Then switch contexts */
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up_restorestack(&rtcb->xcp);
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}
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/* We are not in an interrupt andler. Copy the user C context
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* into the TCB of the task that was previously active. if
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* up_savecontext returns a non-zero value, then this is really the
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* previously running task restarting!
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*/
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else if (!up_savecontext(&rtcb->xcp))
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{
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/* Restore the exception context of the new task that is ready to
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* run (probably tcb). This is the new rtcb at the head of the
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* g_readytorun task list.
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*/
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rtcb = (FAR _TCB*)g_readytorun.head;
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dbg("New Active Task TCB=%p\n", rtcb);
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/* Then switch contexts */
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up_restorecontext(&rtcb->xcp);
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}
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}
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}
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}
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