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/*
* arch/ubicom32/include/asm/semaphore-helper.h
* Semaphore related definitions for Ubicom32 architecture.
*
* (C) Copyright 2009, Ubicom, Inc.
*
* This file is part of the Ubicom32 Linux Kernel Port.
*
* The Ubicom32 Linux Kernel Port is free software: you can redistribute
* it and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 2 of the
* License, or (at your option) any later version.
*
* The Ubicom32 Linux Kernel Port is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Ubicom32 Linux Kernel Port. If not,
* see <http://www.gnu.org/licenses/>.
*
* Ubicom32 implementation derived from (with many thanks):
* arch/m68knommu
* arch/blackfin
* arch/parisc
*/
#ifndef _ASM_UBICOM32_SEMAPHORE_HELPER_H
#define _ASM_UBICOM32_SEMAPHORE_HELPER_H
/*
* SMP- and interrupt-safe semaphores helper functions.
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
/*
* These two _must_ execute atomically wrt each other.
*/
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_interruptible:
* 1 got the lock
* 0 go to sleep
* -EINTR interrupted
*/
static inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 0;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
atomic_inc(&sem->count);
ret = -EINTR;
}
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
/*
* waking_non_zero_trylock:
* 1 failed to lock
* 0 got the lock
*/
static inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&semaphore_wake_lock, flags);
ret = 1;
if (atomic_read(&sem->waking) > 0) {
atomic_dec(&sem->waking);
ret = 0;
} else
atomic_inc(&sem->count);
spin_unlock_irqrestore(&semaphore_wake_lock, flags);
return ret;
}
#endif /* _ASM_UBICOM32_SEMAPHORE_HELPER_H */
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