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