/***********************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__ */