Merged in masayuki2009/nuttx.nuttx/irq_spinlock (pull request #550)
SMP: Introduce spin_lock_irqsave() and spin_unlock_irqrestore() These APIs are simplified version of enter_critical_section() and leave_critical_section() to protect data (e.g. registers) in SMP mode. By using these APIs inside drivers, performace will be improved. Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com> Approved-by: Gregory Nutt <gnutt@nuttx.org>
This commit is contained in:
Masayuki Ishikawa
Gregory Nutt
parent
8bc90a1899
commit
6150299f54
@ -222,6 +222,65 @@ void leave_critical_section(irqstate_t flags);
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# define leave_critical_section(f) up_irq_restore(f)
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#endif
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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 and SPINLOCK_IRQ are enabled:
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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 increment to allow nested call.
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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 and SPINLOCK_IRQ are not enabled:
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* This function is equivalent to enter_critical_section().
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*
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* Input Parameters:
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* None
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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();
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*
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****************************************************************************/
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#if defined (CONFIG_SMP) && defined (CONFIG_SPINLOCK_IRQ)
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irqstate_t spin_lock_irqsave(void);
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#else
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# define spin_lock_irqsave(f) enter_critical_section(f)
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#endif
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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 and SPINLOCK_IRQ are enabled:
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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().
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*
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* If SMP and SPINLOCK_IRQ are not enabled:
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* This function is equivalent to leave_critical_section().
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*
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* Input Parameters:
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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();
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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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#if defined (CONFIG_SMP) && defined (CONFIG_SPINLOCK_IRQ)
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void spin_unlock_irqrestore(irqstate_t flags);
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#else
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# define spin_unlock_irqrestore(f) leave_critical_section(f)
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#endif
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#undef EXTERN
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#ifdef __cplusplus
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}
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@ -249,6 +249,13 @@ config SPINLOCK
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Enables suppport for spinlocks. Spinlocks are current used only for
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SMP suppport.
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config SPINLOCK_IRQ
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bool "Support Spinlocks with IRQ control"
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default n
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---help---
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Enables suppport for spinlocks with IRQ control. This feature can be
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used to protect data in SMP mode.
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config SMP
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bool "Symmetric Multi-Processing (SMP)"
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default n
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@ -37,6 +37,9 @@ CSRCS += irq_initialize.c irq_attach.c irq_dispatch.c irq_unexpectedisr.c
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ifeq ($(CONFIG_SMP),y)
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CSRCS += irq_csection.c
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ifeq ($(CONFIG_SPINLOCK_IRQ),y)
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CSRCS += irq_spinlock.c
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endif
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else ifeq ($(CONFIG_SCHED_INSTRUMENTATION_CSECTION),y)
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CSRCS += irq_csection.c
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endif
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140
sched/irq/irq_spinlock.c
Normal file
140
sched/irq/irq_spinlock.c
Normal file
@ -0,0 +1,140 @@
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/****************************************************************************
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* sched/irq/irq_spinlock.c
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*
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* Copyright (C) 2017 Sony Corporation. All rights reserved.
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* Author: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
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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 <nuttx/spinlock.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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/****************************************************************************
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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_SECTION = 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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/****************************************************************************
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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 and SPINLOCK_IRQ are enabled:
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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 increment to allow nested call.
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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 and SPINLOCK_IRQ are not enabled:
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* This function is equivalent to enter_critical_section().
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*
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* Input Parameters:
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* None
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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();
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*
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****************************************************************************/
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irqstate_t spin_lock_irqsave(void)
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{
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irqstate_t ret;
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ret = up_irq_save();
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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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ASSERT(0 != g_irq_spin_count[me]);
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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 and SPINLOCK_IRQ are enabled:
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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().
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*
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* If SMP and SPINLOCK_IRQ are not enabled:
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* This function is equivalent to leave_critical_section().
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*
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* Input Parameters:
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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();
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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(irqstate_t flags)
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{
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int me = this_cpu();
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ASSERT(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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up_irq_restore(flags);
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}
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