diff options
Diffstat (limited to 'arch/tile/include/asm/spinlock_32.h')
-rw-r--r-- | arch/tile/include/asm/spinlock_32.h | 109 |
1 files changed, 0 insertions, 109 deletions
diff --git a/arch/tile/include/asm/spinlock_32.h b/arch/tile/include/asm/spinlock_32.h deleted file mode 100644 index fb5313d77315..000000000000 --- a/arch/tile/include/asm/spinlock_32.h +++ /dev/null @@ -1,109 +0,0 @@ -/* - * Copyright 2010 Tilera Corporation. All Rights Reserved. - * - * This program 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, version 2. - * - * This program 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, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for - * more details. - * - * 32-bit SMP spinlocks. - */ - -#ifndef _ASM_TILE_SPINLOCK_32_H -#define _ASM_TILE_SPINLOCK_32_H - -#include <linux/atomic.h> -#include <asm/page.h> -#include <linux/compiler.h> - -/* - * We only use even ticket numbers so the '1' inserted by a tns is - * an unambiguous "ticket is busy" flag. - */ -#define TICKET_QUANTUM 2 - - -/* - * SMP ticket spinlocks, allowing only a single CPU anywhere - * - * (the type definitions are in asm/spinlock_types.h) - */ -static inline int arch_spin_is_locked(arch_spinlock_t *lock) -{ - /* - * Note that even if a new ticket is in the process of being - * acquired, so lock->next_ticket is 1, it's still reasonable - * to claim the lock is held, since it will be momentarily - * if not already. There's no need to wait for a "valid" - * lock->next_ticket to become available. - * Use READ_ONCE() to ensure that calling this in a loop is OK. - */ - int curr = READ_ONCE(lock->current_ticket); - int next = READ_ONCE(lock->next_ticket); - - return next != curr; -} - -void arch_spin_lock(arch_spinlock_t *lock); - -int arch_spin_trylock(arch_spinlock_t *lock); - -static inline void arch_spin_unlock(arch_spinlock_t *lock) -{ - /* For efficiency, overlap fetching the old ticket with the wmb(). */ - int old_ticket = lock->current_ticket; - wmb(); /* guarantee anything modified under the lock is visible */ - lock->current_ticket = old_ticket + TICKET_QUANTUM; -} - -/* - * Read-write spinlocks, allowing multiple readers - * but only one writer. - * - * We use a "tns/store-back" technique on a single word to manage - * the lock state, looping around to retry if the tns returns 1. - */ - -/* Internal layout of the word; do not use. */ -#define _WR_NEXT_SHIFT 8 -#define _WR_CURR_SHIFT 16 -#define _WR_WIDTH 8 -#define _RD_COUNT_SHIFT 24 -#define _RD_COUNT_WIDTH 8 - -/** - * arch_read_lock() - acquire a read lock. - */ -void arch_read_lock(arch_rwlock_t *rwlock); - -/** - * arch_write_lock() - acquire a write lock. - */ -void arch_write_lock(arch_rwlock_t *rwlock); - -/** - * arch_read_trylock() - try to acquire a read lock. - */ -int arch_read_trylock(arch_rwlock_t *rwlock); - -/** - * arch_write_trylock() - try to acquire a write lock. - */ -int arch_write_trylock(arch_rwlock_t *rwlock); - -/** - * arch_read_unlock() - release a read lock. - */ -void arch_read_unlock(arch_rwlock_t *rwlock); - -/** - * arch_write_unlock() - release a write lock. - */ -void arch_write_unlock(arch_rwlock_t *rwlock); - -#endif /* _ASM_TILE_SPINLOCK_32_H */ |