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- asm
- octeon
- cvmx-spinlock.h
/***********************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 <asm/octeon/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__ */