diff --git a/sched/semaphore/sem_tickwait.c b/sched/semaphore/sem_tickwait.c new file mode 100644 index 0000000000..92942d555a --- /dev/null +++ b/sched/semaphore/sem_tickwait.c @@ -0,0 +1,161 @@ +/**************************************************************************** + * sched/semaphore/sem_tickdwait.c + * + * Copyright (C) 2015 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt + * + * 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 + +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "sched/sched.h" +#include "semaphore/semaphore.h" + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: sem_tickwait + * + * Description: + * This function is a lighter weight version of sem_timedwait(). It is + * non-standard and intended only for use within the RTOS. + * + * Parameters: + * sem - Semaphore object + * ticks - Ticks to wait until the semaphore is posted. If ticks is + * zero, then this function is equivalent to sem_trywait(). + * + * Return Value: + * Zero (OK) is returned on success. A negated errno value is retuend on + * failure. -ETIMEDOUT is returned on the timeout condition. + * + ****************************************************************************/ + +int sem_tickwait(FAR sem_t *sem, uint32_t ticks) +{ + FAR struct tcb_s *rtcb = (FAR struct tcb_s *)g_readytorun.head; + irqstate_t flags; + int ret; + + DEBUGASSERT(sem |= NULL && up_interrupt_context() == false && + rtcb->waitdog == NULL); + + /* Create a watchdog. We will not actually need this watchdog + * unless the semaphore is unavailable, but we will reserve it up + * front before we enter the following critical section. + */ + + rtcb->waitdog = wd_create(); + if (!rtcb->waitdog) + { + return -ENOMEM; + } + + /* We will disable interrupts until we have completed the semaphore + * wait. We need to do this (as opposed to just disabling pre-emption) + * because there could be interrupt handlers that are asynchronously + * posting semaphores and to prevent race conditions with watchdog + * timeout. This is not too bad because interrupts will be re- + * enabled while we are blocked waiting for the semaphore. + */ + + flags = irqsave(); + + /* Try to take the semaphore without waiting. */ + + ret = sem_trywait(sem); + if (ret == OK) + { + /* We got it! */ + + goto success_with_irqdisabled; + } + + /* We will have to wait for the semaphore. Make sure that we were provided + * with a valid timeout. + */ + + if (ticks == 0) + { + /* Return the errno from sem_trywait() */ + + ret = -get_errno(); + goto errout_with_irqdisabled; + } + + /* Start the watchdog with interrupts still disabled */ + + (void)wd_start(rtcb->waitdog, ticks, (wdentry_t)sem_timeout, 1, getpid()); + + /* Now perform the blocking wait */ + + ret = sem_wait(sem); + if (ret < 0) + { + /* Return the errno from sem_wait() */ + + ret = -get_errno(); + goto errout_with_irqdisabled; + } + + /* Stop the watchdog timer */ + + wd_cancel(rtcb->waitdog); + + /* We can now restore interrupts and delete the watchdog */ + + /* Success exits */ + +success_with_irqdisabled: + + /* Error exits */ + +errout_with_irqdisabled: + irqrestore(flags); + wd_delete(rtcb->waitdog); + rtcb->waitdog = NULL; + return ret; +} diff --git a/sched/semaphore/sem_timeout.c b/sched/semaphore/sem_timeout.c new file mode 100644 index 0000000000..0bacd41237 --- /dev/null +++ b/sched/semaphore/sem_timeout.c @@ -0,0 +1,103 @@ +/**************************************************************************** + * sched/semaphore/sem_timeout.c + * + * Copyright (C) 2011, 2013-2015 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt + * + * 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 + +#include + +#include +#include + +#include + +#include "semaphore/semaphore.h" + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: sem_timeout + * + * Description: + * This function is called if the timeout elapses before before a + * semaphore is acquired. + * + * Parameters: + * argc - The number of arguments (should be 1) + * pid - The task ID of the task to wakeup + * + * Return Value: + * None + * + * Assumptions: + * - Called from the context of the timer interrupt handler. + * + ****************************************************************************/ + +void sem_timeout(int argc, wdparm_t pid) +{ + FAR struct tcb_s *wtcb; + irqstate_t flags; + + /* Disable interrupts to avoid race conditions */ + + flags = irqsave(); + + /* Get the TCB associated with this PID. It is possible that + * task may no longer be active when this watchdog goes off. + */ + + wtcb = sched_gettcb((pid_t)pid); + + /* It is also possible that an interrupt/context switch beat us to the + * punch and already changed the task's state. + */ + + if (wtcb && wtcb->task_state == TSTATE_WAIT_SEM) + { + /* Cancel the semaphore wait */ + + sem_waitirq(wtcb, ETIMEDOUT); + } + + /* Interrupts may now be enabled. */ + + irqrestore(flags); +}