| /***********************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__ */ |
