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Diffstat (limited to 'arch/mips/include/asm/octeon/cvmx-spinlock.h')
| -rw-r--r-- | arch/mips/include/asm/octeon/cvmx-spinlock.h | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/arch/mips/include/asm/octeon/cvmx-spinlock.h b/arch/mips/include/asm/octeon/cvmx-spinlock.h new file mode 100644 index 00000000000..2fbf0871df1 --- /dev/null +++ b/arch/mips/include/asm/octeon/cvmx-spinlock.h @@ -0,0 +1,232 @@ +/***********************license start*************** + * Author: Cavium Networks + * + * Contact: support@caviumnetworks.com + * This file is part of the OCTEON SDK + * + * Copyright (c) 2003-2008 Cavium Networks + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, Version 2, as + * published by the Free Software Foundation. + * + * This file is distributed in the hope that it will be useful, but + * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or + * NONINFRINGEMENT. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License + * along with this file; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * or visit http://www.gnu.org/licenses/. + * + * This file may also be available under a different license from Cavium. + * Contact Cavium Networks for more information + ***********************license end**************************************/ + +/** + * Implementation of spinlocks for Octeon CVMX. Although similar in + * function to Linux kernel spinlocks, they are not compatible. + * Octeon CVMX spinlocks are only used to synchronize with the boot + * monitor and other non-Linux programs running in the system. + */ + +#ifndef __CVMX_SPINLOCK_H__ +#define __CVMX_SPINLOCK_H__ + +#include "cvmx-asm.h" + +/* Spinlocks for Octeon */ + +/* define these to enable recursive spinlock debugging */ +/*#define CVMX_SPINLOCK_DEBUG */ + +/** + * Spinlocks for Octeon CVMX + */ +typedef struct { + volatile uint32_t value; +} cvmx_spinlock_t; + +/* note - macros not expanded in inline ASM, so values hardcoded */ +#define CVMX_SPINLOCK_UNLOCKED_VAL 0 +#define CVMX_SPINLOCK_LOCKED_VAL 1 + +#define CVMX_SPINLOCK_UNLOCKED_INITIALIZER {CVMX_SPINLOCK_UNLOCKED_VAL} + +/** + * Initialize a spinlock + * + * @lock: Lock to initialize + */ +static inline void cvmx_spinlock_init(cvmx_spinlock_t *lock) +{ + lock->value = CVMX_SPINLOCK_UNLOCKED_VAL; +} + +/** + * Return non-zero if the spinlock is currently locked + * + * @lock: Lock to check + * Returns Non-zero if locked + */ +static inline int cvmx_spinlock_locked(cvmx_spinlock_t *lock) +{ + return lock->value != CVMX_SPINLOCK_UNLOCKED_VAL; +} + +/** + * Releases lock + * + * @lock: pointer to lock structure + */ +static inline void cvmx_spinlock_unlock(cvmx_spinlock_t *lock) +{ + CVMX_SYNCWS; + lock->value = 0; + CVMX_SYNCWS; +} + +/** + * Attempts to take the lock, but does not spin if lock is not available. + * May take some time to acquire the lock even if it is available + * due to the ll/sc not succeeding. + * + * @lock: pointer to lock structure + * + * Returns 0: lock successfully taken + * 1: lock not taken, held by someone else + * These return values match the Linux semantics. + */ + +static inline unsigned int cvmx_spinlock_trylock(cvmx_spinlock_t *lock) +{ + unsigned int tmp; + + __asm__ __volatile__(".set noreorder \n" + "1: ll %[tmp], %[val] \n" + /* if lock held, fail immediately */ + " bnez %[tmp], 2f \n" + " li %[tmp], 1 \n" + " sc %[tmp], %[val] \n" + " beqz %[tmp], 1b \n" + " li %[tmp], 0 \n" + "2: \n" + ".set reorder \n" : + [val] "+m"(lock->value), [tmp] "=&r"(tmp) + : : "memory"); + + return tmp != 0; /* normalize to 0 or 1 */ +} + +/** + * Gets lock, spins until lock is taken + * + * @lock: pointer to lock structure + */ +static inline void cvmx_spinlock_lock(cvmx_spinlock_t *lock) +{ + unsigned int tmp; + + __asm__ __volatile__(".set noreorder \n" + "1: ll %[tmp], %[val] \n" + " bnez %[tmp], 1b \n" + " li %[tmp], 1 \n" + " sc %[tmp], %[val] \n" + " beqz %[tmp], 1b \n" + " nop \n" + ".set reorder \n" : + [val] "+m"(lock->value), [tmp] "=&r"(tmp) + : : "memory"); + +} + +/** ******************************************************************** + * Bit spinlocks + * These spinlocks use a single bit (bit 31) of a 32 bit word for locking. + * The rest of the bits in the word are left undisturbed. This enables more + * compact data structures as only 1 bit is consumed for the lock. + * + */ + +/** + * Gets lock, spins until lock is taken + * Preserves the low 31 bits of the 32 bit + * word used for the lock. + * + * + * @word: word to lock bit 31 of + */ +static inline void cvmx_spinlock_bit_lock(uint32_t *word) +{ + unsigned int tmp; + unsigned int sav; + + __asm__ __volatile__(".set noreorder \n" + ".set noat \n" + "1: ll %[tmp], %[val] \n" + " bbit1 %[tmp], 31, 1b \n" + " li $at, 1 \n" + " ins %[tmp], $at, 31, 1 \n" + " sc %[tmp], %[val] \n" + " beqz %[tmp], 1b \n" + " nop \n" + ".set at \n" + ".set reorder \n" : + [val] "+m"(*word), [tmp] "=&r"(tmp), [sav] "=&r"(sav) + : : "memory"); + +} + +/** + * Attempts to get lock, returns immediately with success/failure + * Preserves the low 31 bits of the 32 bit + * word used for the lock. + * + * + * @word: word to lock bit 31 of + * Returns 0: lock successfully taken + * 1: lock not taken, held by someone else + * These return values match the Linux semantics. + */ +static inline unsigned int cvmx_spinlock_bit_trylock(uint32_t *word) +{ + unsigned int tmp; + + __asm__ __volatile__(".set noreorder\n\t" + ".set noat\n" + "1: ll %[tmp], %[val] \n" + /* if lock held, fail immediately */ + " bbit1 %[tmp], 31, 2f \n" + " li $at, 1 \n" + " ins %[tmp], $at, 31, 1 \n" + " sc %[tmp], %[val] \n" + " beqz %[tmp], 1b \n" + " li %[tmp], 0 \n" + "2: \n" + ".set at \n" + ".set reorder \n" : + [val] "+m"(*word), [tmp] "=&r"(tmp) + : : "memory"); + + return tmp != 0; /* normalize to 0 or 1 */ +} + +/** + * Releases bit lock + * + * Unconditionally clears bit 31 of the lock word. Note that this is + * done non-atomically, as this implementation assumes that the rest + * of the bits in the word are protected by the lock. + * + * @word: word to unlock bit 31 in + */ +static inline void cvmx_spinlock_bit_unlock(uint32_t *word) +{ + CVMX_SYNCWS; + *word &= ~(1UL << 31); + CVMX_SYNCWS; +} + +#endif /* __CVMX_SPINLOCK_H__ */ |