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Diffstat (limited to '')
| -rw-r--r-- | arch/hexagon/include/asm/spinlock.h | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/spinlock.h b/arch/hexagon/include/asm/spinlock.h new file mode 100644 index 000000000..e090f6a15 --- /dev/null +++ b/arch/hexagon/include/asm/spinlock.h @@ -0,0 +1,172 @@ +/* + * Spinlock support for the Hexagon architecture + * + * Copyright (c) 2010-2011, The Linux Foundation. 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 version 2 and + * only version 2 as published by the Free Software Foundation. + * + * 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. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef _ASM_SPINLOCK_H +#define _ASM_SPINLOCK_H + +#include <asm/irqflags.h> +#include <asm/barrier.h> +#include <asm/processor.h> + +/* + * This file is pulled in for SMP builds. + * Really need to check all the barrier stuff for "true" SMP + */ + +/* + * Read locks: + * - load the lock value + * - increment it + * - if the lock value is still negative, go back and try again. + * - unsuccessful store is unsuccessful. Go back and try again. Loser. + * - successful store new lock value if positive -> lock acquired + */ +static inline void arch_read_lock(arch_rwlock_t *lock) +{ + __asm__ __volatile__( + "1: R6 = memw_locked(%0);\n" + " { P3 = cmp.ge(R6,#0); R6 = add(R6,#1);}\n" + " { if (!P3) jump 1b; }\n" + " memw_locked(%0,P3) = R6;\n" + " { if (!P3) jump 1b; }\n" + : + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + +} + +static inline void arch_read_unlock(arch_rwlock_t *lock) +{ + __asm__ __volatile__( + "1: R6 = memw_locked(%0);\n" + " R6 = add(R6,#-1);\n" + " memw_locked(%0,P3) = R6\n" + " if (!P3) jump 1b;\n" + : + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + +} + +/* I think this returns 0 on fail, 1 on success. */ +static inline int arch_read_trylock(arch_rwlock_t *lock) +{ + int temp; + __asm__ __volatile__( + " R6 = memw_locked(%1);\n" + " { %0 = #0; P3 = cmp.ge(R6,#0); R6 = add(R6,#1);}\n" + " { if (!P3) jump 1f; }\n" + " memw_locked(%1,P3) = R6;\n" + " { %0 = P3 }\n" + "1:\n" + : "=&r" (temp) + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + return temp; +} + +/* Stuffs a -1 in the lock value? */ +static inline void arch_write_lock(arch_rwlock_t *lock) +{ + __asm__ __volatile__( + "1: R6 = memw_locked(%0)\n" + " { P3 = cmp.eq(R6,#0); R6 = #-1;}\n" + " { if (!P3) jump 1b; }\n" + " memw_locked(%0,P3) = R6;\n" + " { if (!P3) jump 1b; }\n" + : + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); +} + + +static inline int arch_write_trylock(arch_rwlock_t *lock) +{ + int temp; + __asm__ __volatile__( + " R6 = memw_locked(%1)\n" + " { %0 = #0; P3 = cmp.eq(R6,#0); R6 = #-1;}\n" + " { if (!P3) jump 1f; }\n" + " memw_locked(%1,P3) = R6;\n" + " %0 = P3;\n" + "1:\n" + : "=&r" (temp) + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + return temp; + +} + +static inline void arch_write_unlock(arch_rwlock_t *lock) +{ + smp_mb(); + lock->lock = 0; +} + +static inline void arch_spin_lock(arch_spinlock_t *lock) +{ + __asm__ __volatile__( + "1: R6 = memw_locked(%0);\n" + " P3 = cmp.eq(R6,#0);\n" + " { if (!P3) jump 1b; R6 = #1; }\n" + " memw_locked(%0,P3) = R6;\n" + " { if (!P3) jump 1b; }\n" + : + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + +} + +static inline void arch_spin_unlock(arch_spinlock_t *lock) +{ + smp_mb(); + lock->lock = 0; +} + +static inline unsigned int arch_spin_trylock(arch_spinlock_t *lock) +{ + int temp; + __asm__ __volatile__( + " R6 = memw_locked(%1);\n" + " P3 = cmp.eq(R6,#0);\n" + " { if (!P3) jump 1f; R6 = #1; %0 = #0; }\n" + " memw_locked(%1,P3) = R6;\n" + " %0 = P3;\n" + "1:\n" + : "=&r" (temp) + : "r" (&lock->lock) + : "memory", "r6", "p3" + ); + return temp; +} + +/* + * SMP spinlocks are intended to allow only a single CPU at the lock + */ +#define arch_spin_is_locked(x) ((x)->lock != 0) + +#endif |