diff options
Diffstat (limited to 'nuttx/arch/arm/src/armv6-m/up_blocktask.c')
| -rw-r--r-- | nuttx/arch/arm/src/armv6-m/up_blocktask.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/armv6-m/up_blocktask.c b/nuttx/arch/arm/src/armv6-m/up_blocktask.c new file mode 100644 index 000000000..a332cbefd --- /dev/null +++ b/nuttx/arch/arm/src/armv6-m/up_blocktask.c @@ -0,0 +1,166 @@ +/**************************************************************************** + * arch/arm/src/armv6-m/up_blocktask.c + * + * Copyright (C) 2013 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 <stdbool.h> +#include <sched.h> +#include <debug.h> + +#include <nuttx/arch.h> + +#include "os_internal.h" +#include "up_internal.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: up_block_task + * + * Description: + * The currently executing task at the head of the ready to run list must + * be stopped. Save its context and move it to the inactive list specified + * by task_state. + * + * Inputs: + * tcb: Refers to a task in the ready-to-run list (normally the task at + * the head of the list). It most be stopped, its context saved and + * moved into one of the waiting task lists. It it was the task at the + * head of the ready-to-run list, then a context to the new ready to run + * task must be performed. + * task_state: Specifies which waiting task list should be hold the + * blocked task TCB. + * + ****************************************************************************/ + +void up_block_task(struct tcb_s *tcb, tstate_t task_state) +{ + /* Verify that the context switch can be performed */ + + if ((tcb->task_state < FIRST_READY_TO_RUN_STATE) || + (tcb->task_state > LAST_READY_TO_RUN_STATE)) + { + PANIC(OSERR_BADBLOCKSTATE); + } + else + { + struct tcb_s *rtcb = (struct tcb_s*)g_readytorun.head; + bool switch_needed; + + /* Remove the tcb task from the ready-to-run list. If we + * are blocking the task at the head of the task list (the + * most likely case), then a context switch to the next + * ready-to-run task is needed. In this case, it should + * also be true that rtcb == tcb. + */ + + switch_needed = sched_removereadytorun(tcb); + + /* Add the task to the specified blocked task list */ + + sched_addblocked(tcb, (tstate_t)task_state); + + /* If there are any pending tasks, then add them to the g_readytorun + * task list now + */ + + if (g_pendingtasks.head) + { + switch_needed |= sched_mergepending(); + } + + /* Now, perform the context switch if one is needed */ + + if (switch_needed) + { + /* Are we in an interrupt handler? */ + + if (current_regs) + { + /* Yes, then we have to do things differently. + * Just copy the current_regs into the OLD rtcb. + */ + + up_savestate(rtcb->xcp.regs); + + /* Restore the exception context of the rtcb at the (new) head + * of the g_readytorun task list. + */ + + rtcb = (struct tcb_s*)g_readytorun.head; + + /* Then switch contexts */ + + up_restorestate(rtcb->xcp.regs); + } + + /* No, then we will need to perform the user context switch */ + + else + { + /* Switch context to the context of the task at the head of the + * ready to run list. + */ + + struct tcb_s *nexttcb = (struct tcb_s*)g_readytorun.head; + up_switchcontext(rtcb->xcp.regs, nexttcb->xcp.regs); + + /* up_switchcontext forces a context switch to the task at the + * head of the ready-to-run list. It does not 'return' in the + * normal sense. When it does return, it is because the blocked + * task is again ready to run and has execution priority. + */ + } + } + } +} |