422 lines
12 KiB
C
422 lines
12 KiB
C
/****************************************************************************
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* sched/irq/irq_spinlock.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <nuttx/spinlock.h>
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#include <assert.h>
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#include <sys/types.h>
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#include <arch/irq.h>
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#include "sched/sched.h"
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#if defined(CONFIG_SMP)
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/* Used for access control */
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static volatile spinlock_t g_irq_spin = SP_UNLOCKED;
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/* Handles nested calls to spin_lock_irqsave and spin_unlock_irqrestore */
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static volatile uint8_t g_irq_spin_count[CONFIG_SMP_NCPUS];
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#ifdef CONFIG_RW_SPINLOCK
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/* Used for access control */
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static volatile rwlock_t g_irq_rwspin = RW_SP_UNLOCKED;
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/* Handles nested calls to write_lock_irqsave and write_unlock_irqrestore */
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static volatile uint8_t g_irq_rwspin_count[CONFIG_SMP_NCPUS];
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: spin_lock_irqsave
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*
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* Description:
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* If SMP is enabled:
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* If the argument lock is not specified (i.e. NULL),
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* disable local interrupts and take the global spinlock (g_irq_spin)
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* if the call counter (g_irq_spin_count[cpu]) equals to 0. Then the
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* counter on the CPU is incremented to allow nested call and return
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* the interrupt state.
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*
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* If the argument lock is specified,
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* disable local interrupts and take the given lock and return the
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* interrupt state.
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*
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* NOTE: This API is very simple to protect data (e.g. H/W register
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* or internal data structure) in SMP mode. But do not use this API
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* with kernel APIs which suspend a caller thread. (e.g. nxsem_wait)
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_save().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used
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* and can be nested. Otherwise, nested call for the same lock
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* would cause a deadlock
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*
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* Returned Value:
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* An opaque, architecture-specific value that represents the state of
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* the interrupts prior to the call to spin_lock_irqsave(lock);
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*
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****************************************************************************/
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irqstate_t spin_lock_irqsave(spinlock_t *lock)
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{
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irqstate_t ret;
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ret = up_irq_save();
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if (NULL == lock)
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{
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int me = this_cpu();
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if (0 == g_irq_spin_count[me])
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{
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spin_lock(&g_irq_spin);
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}
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g_irq_spin_count[me]++;
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DEBUGASSERT(0 != g_irq_spin_count[me]);
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}
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else
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{
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spin_lock(lock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: spin_lock_irqsave_wo_note
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****************************************************************************/
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irqstate_t spin_lock_irqsave_wo_note(spinlock_t *lock)
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{
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irqstate_t ret;
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ret = up_irq_save();
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if (NULL == lock)
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{
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int me = this_cpu();
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if (0 == g_irq_spin_count[me])
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{
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spin_lock_wo_note(&g_irq_spin);
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}
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g_irq_spin_count[me]++;
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DEBUGASSERT(0 != g_irq_spin_count[me]);
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}
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else
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{
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spin_lock_wo_note(lock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: spin_unlock_irqrestore
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*
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* Description:
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* If SMP is enabled:
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* If the argument lock is not specified (i.e. NULL),
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* decrement the call counter (g_irq_spin_count[cpu]) and if it
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* decrements to zero then release the spinlock (g_irq_spin) and
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* restore the interrupt state as it was prior to the previous call to
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* spin_lock_irqsave(NULL).
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*
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* If the argument lock is specified, release the lock and restore
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* the interrupt state as it was prior to the previous call to
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* spin_lock_irqsave(lock).
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_restore().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used.
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*
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* flags - The architecture-specific value that represents the state of
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* the interrupts prior to the call to spin_lock_irqsave(lock);
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void spin_unlock_irqrestore(spinlock_t *lock, irqstate_t flags)
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{
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if (NULL == lock)
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{
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int me = this_cpu();
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DEBUGASSERT(0 < g_irq_spin_count[me]);
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g_irq_spin_count[me]--;
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if (0 == g_irq_spin_count[me])
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{
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spin_unlock(&g_irq_spin);
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}
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}
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else
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{
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spin_unlock(lock);
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}
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up_irq_restore(flags);
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}
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/****************************************************************************
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* Name: spin_lock_irqsave_wo_note
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****************************************************************************/
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void spin_unlock_irqrestore_wo_note(spinlock_t *lock, irqstate_t flags)
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{
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if (NULL == lock)
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{
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int me = this_cpu();
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DEBUGASSERT(0 < g_irq_spin_count[me]);
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g_irq_spin_count[me]--;
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if (0 == g_irq_spin_count[me])
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{
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spin_unlock_wo_note(&g_irq_spin);
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}
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}
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else
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{
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spin_unlock_wo_note(lock);
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}
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up_irq_restore(flags);
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}
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#ifdef CONFIG_RW_SPINLOCK
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/****************************************************************************
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* Name: read_lock_irqsave
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*
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* Description:
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* If SMP is enabled:
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* If the 'lock' argument is not specified (i.e. NULL), disable local
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* interrupts and take the global read write spinlock (g_irq_rwspin)
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* and increase g_irq_rwspin.
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*
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* If the 'lock' argument is specified,
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* disable local interrupts and take the lock spinlock and return
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* the interrupt state.
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*
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* NOTE: This API is very simple to protect data (e.g. H/W register
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* or internal data structure) in SMP mode. Do not use this API
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* with kernel APIs which suspend a caller thread. (e.g. nxsem_wait)
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_save().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used
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* and can be nested. Otherwise, nested call for the same lock
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* would cause a deadlock
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*
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* Returned Value:
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* An opaque, architecture-specific value that represents the state of
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* the interrupts prior to the call to write_lock_irqsave(lock);
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*
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****************************************************************************/
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irqstate_t read_lock_irqsave(FAR rwlock_t *lock)
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{
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irqstate_t ret;
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ret = up_irq_save();
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if (NULL == lock)
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{
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read_lock(&g_irq_rwspin);
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}
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else
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{
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read_lock(lock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: read_unlock_irqrestore
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*
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* Description:
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* If SMP is enabled:
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* If the argument lock is not specified (i.e. NULL),
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* decrement the call counter (g_irq_rwspin) and restore the interrupt
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* state as it was prior to the previous call to read_lock_irqsave(NULL).
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*
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* If the argument lock is specified, release the lock and
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* restore the interrupt state as it was prior to the previous call to
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* read_lock_irqsave(lock).
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_restore().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used.
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*
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* flags - The architecture-specific value that represents the state of
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* the interrupts prior to the call to read_lock_irqsave(lock);
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void read_unlock_irqrestore(rwlock_t *lock, irqstate_t flags)
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{
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if (NULL == lock)
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{
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read_unlock(&g_irq_rwspin);
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}
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else
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{
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read_unlock(lock);
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}
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up_irq_restore(flags);
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}
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/****************************************************************************
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* Name: write_lock_irqsave
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*
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* Description:
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* If SMP is enabled:
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* If the argument lock is not specified (i.e. NULL),
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* disable local interrupts and take the global spinlock (g_irq_rwspin)
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* if the call counter (g_irq_rwspin_count[cpu]) equals to 0. Then
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* the counter on the CPU is incremented to allow nested calls and return
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* the interrupt state.
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*
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* If the argument lock is specified,
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* disable local interrupts and take the lock spinlock and return
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* the interrupt state.
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*
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* NOTE: This API is very simple to protect data (e.g. H/W register
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* or internal data structure) in SMP mode. But do not use this API
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* with kernel APIs which suspend a caller thread. (e.g. nxsem_wait)
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_save().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used
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* and can be nested. Otherwise, nested call for the same lock
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* would cause a deadlock
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*
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* Returned Value:
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* An opaque, architecture-specific value that represents the state of
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* the interrupts prior to the call to write_lock_irqsave(lock);
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*
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****************************************************************************/
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irqstate_t write_lock_irqsave(rwlock_t *lock)
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{
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irqstate_t ret;
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ret = up_irq_save();
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if (NULL == lock)
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{
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int me = this_cpu();
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if (0 == g_irq_rwspin_count[me])
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{
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write_lock(&g_irq_rwspin);
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}
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g_irq_rwspin_count[me]++;
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DEBUGASSERT(0 != g_irq_rwspin_count[me]);
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}
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else
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{
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write_lock(lock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: write_unlock_irqrestore
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*
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* Description:
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* If SMP is enabled:
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* If the argument lock is not specified (i.e. NULL),
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* decrement the call counter (g_irq_rwspin_count[cpu]) and if it
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* decrements to zero then release the spinlock (g_irq_rwspin) and
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* restore the interrupt state as it was prior to the previous call to
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* write_lock_irqsave(NULL).
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*
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* If the argument lock is specified, release the lock and
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* restore the interrupt state as it was prior to the previous call to
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* write_lock_irqsave(lock).
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*
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* If SMP is not enabled:
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* This function is equivalent to up_irq_restore().
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*
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* Input Parameters:
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* lock - Caller specific spinlock. If specified NULL, g_irq_spin is used.
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*
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* flags - The architecture-specific value that represents the state of
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* the interrupts prior to the call to write_lock_irqsave(lock);
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void write_unlock_irqrestore(rwlock_t *lock, irqstate_t flags)
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{
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if (NULL == lock)
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{
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int me = this_cpu();
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DEBUGASSERT(0 < g_irq_rwspin_count[me]);
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g_irq_rwspin_count[me]--;
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if (0 == g_irq_rwspin_count[me])
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{
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write_unlock(&g_irq_rwspin);
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}
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}
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else
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{
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write_unlock(lock);
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}
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up_irq_restore(flags);
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}
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#endif /* CONFIG_RW_SPINLOCK */
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#endif /* CONFIG_SMP */
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