| 1 | /* |
| 2 | * arch/ubicom32/include/asm/semaphore-helper.h |
| 3 | * Semaphore related definitions for Ubicom32 architecture. |
| 4 | * |
| 5 | * (C) Copyright 2009, Ubicom, Inc. |
| 6 | * |
| 7 | * This file is part of the Ubicom32 Linux Kernel Port. |
| 8 | * |
| 9 | * The Ubicom32 Linux Kernel Port is free software: you can redistribute |
| 10 | * it and/or modify it under the terms of the GNU General Public License |
| 11 | * as published by the Free Software Foundation, either version 2 of the |
| 12 | * License, or (at your option) any later version. |
| 13 | * |
| 14 | * The Ubicom32 Linux Kernel Port is distributed in the hope that it |
| 15 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 16 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 17 | * the GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with the Ubicom32 Linux Kernel Port. If not, |
| 21 | * see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | * Ubicom32 implementation derived from (with many thanks): |
| 24 | * arch/m68knommu |
| 25 | * arch/blackfin |
| 26 | * arch/parisc |
| 27 | */ |
| 28 | #ifndef _ASM_UBICOM32_SEMAPHORE_HELPER_H |
| 29 | #define _ASM_UBICOM32_SEMAPHORE_HELPER_H |
| 30 | |
| 31 | /* |
| 32 | * SMP- and interrupt-safe semaphores helper functions. |
| 33 | * |
| 34 | * (C) Copyright 1996 Linus Torvalds |
| 35 | * |
| 36 | * m68k version by Andreas Schwab |
| 37 | */ |
| 38 | |
| 39 | |
| 40 | /* |
| 41 | * These two _must_ execute atomically wrt each other. |
| 42 | */ |
| 43 | static inline void wake_one_more(struct semaphore * sem) |
| 44 | { |
| 45 | atomic_inc(&sem->waking); |
| 46 | } |
| 47 | |
| 48 | static inline int waking_non_zero(struct semaphore *sem) |
| 49 | { |
| 50 | int ret; |
| 51 | unsigned long flags; |
| 52 | |
| 53 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 54 | ret = 0; |
| 55 | if (atomic_read(&sem->waking) > 0) { |
| 56 | atomic_dec(&sem->waking); |
| 57 | ret = 1; |
| 58 | } |
| 59 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 60 | return ret; |
| 61 | } |
| 62 | |
| 63 | /* |
| 64 | * waking_non_zero_interruptible: |
| 65 | * 1 got the lock |
| 66 | * 0 go to sleep |
| 67 | * -EINTR interrupted |
| 68 | */ |
| 69 | static inline int waking_non_zero_interruptible(struct semaphore *sem, |
| 70 | struct task_struct *tsk) |
| 71 | { |
| 72 | int ret; |
| 73 | unsigned long flags; |
| 74 | |
| 75 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 76 | ret = 0; |
| 77 | if (atomic_read(&sem->waking) > 0) { |
| 78 | atomic_dec(&sem->waking); |
| 79 | ret = 1; |
| 80 | } else if (signal_pending(tsk)) { |
| 81 | atomic_inc(&sem->count); |
| 82 | ret = -EINTR; |
| 83 | } |
| 84 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 85 | return ret; |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * waking_non_zero_trylock: |
| 90 | * 1 failed to lock |
| 91 | * 0 got the lock |
| 92 | */ |
| 93 | static inline int waking_non_zero_trylock(struct semaphore *sem) |
| 94 | { |
| 95 | int ret; |
| 96 | unsigned long flags; |
| 97 | |
| 98 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 99 | ret = 1; |
| 100 | if (atomic_read(&sem->waking) > 0) { |
| 101 | atomic_dec(&sem->waking); |
| 102 | ret = 0; |
| 103 | } else |
| 104 | atomic_inc(&sem->count); |
| 105 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 106 | return ret; |
| 107 | } |
| 108 | |
| 109 | #endif /* _ASM_UBICOM32_SEMAPHORE_HELPER_H */ |
| 110 | |
