147 lines
4.9 KiB
C
147 lines
4.9 KiB
C
/****************************************************************************
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* arch/arm/src/armv7-m/up_unblocktask.c
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*
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* Copyright (C) 2007-2009, 2012, 2015 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 <sched.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include "sched/sched.h"
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#include "clock/clock.h"
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#include "up_internal.h"
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/****************************************************************************
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* Public Functions
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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(struct tcb_s *tcb)
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{
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struct tcb_s *rtcb = (struct tcb_s*)g_readytorun.head;
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/* Verify that the context switch can be performed */
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ASSERT((tcb->task_state >= FIRST_BLOCKED_STATE) &&
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(tcb->task_state <= LAST_BLOCKED_STATE));
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/* Remove the task from the blocked task list */
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sched_removeblocked(tcb);
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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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/* Update scheduler parameters */
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sched_suspend_scheduler(rtcb);
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/* Are we in an interrupt handler? */
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if (current_regs)
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{
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/* Yes, then we have to do things differently.
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* Just copy the current_regs into the OLD rtcb.
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*/
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up_savestate(rtcb->xcp.regs);
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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 = (struct tcb_s*)g_readytorun.head;
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/* Update scheduler parameters */
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sched_resume_scheduler(rtcb);
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/* Then switch contexts */
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up_restorestate(rtcb->xcp.regs);
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}
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/* No, then we will need to perform the user context switch */
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else
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{
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struct tcb_s *nexttcb = (struct tcb_s*)g_readytorun.head;
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/* Update scheduler parameters */
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sched_resume_scheduler(nexttcb);
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/* Switch context to the context of the task at the head of the
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* ready to run list.
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*/
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up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs);
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/* up_switchcontext forces a context switch to the task at the
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* head of the ready-to-run list. It does not 'return' in the
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* normal sense. When it does return, it is because the blocked
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* task is again ready to run and has execution priority.
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*/
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}
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}
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}
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