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/***********************license start***************
* Copyright (c) 2003-2010 Cavium Networks (support@cavium.com). All rights
* reserved.
*
*
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*
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* This Software, including technical data, may be subject to U.S. export control
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***********************license end**************************************/
/**
* @file
*
* Implementation of spinlocks.
*
* <hr>$Revision: 49448 $<hr>
*/
#ifndef __CVMX_SPINLOCK_H__
#define __CVMX_SPINLOCK_H__
#include "cvmx-asm.h"
#ifdef __cplusplus
extern "C" {
#endif
/* Spinlocks for Octeon */
// define these to enable recursive spinlock debugging
//#define CVMX_SPINLOCK_DEBUG
/**
* Spinlocks for Octeon
*/
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
*
* @param 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
*
* @param lock Lock to check
* @return Non-zero if locked
*/
static inline int cvmx_spinlock_locked(cvmx_spinlock_t *lock)
{
return (lock->value != CVMX_SPINLOCK_UNLOCKED_VAL);
}
/**
* Releases lock
*
* @param 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.
*
* @param lock pointer to lock structure
*
* @return 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"
" bnez %[tmp], 2f \n" // if lock held, fail immediately
" 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); /* normalize to 0 or 1 */
}
/**
* Gets lock, spins until lock is taken
*
* @param 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.
*
*
* @param 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.
*
*
* @param word word to lock bit 31 of
* @return 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"
".set noat \n"
"1: ll %[tmp], %[val] \n"
" bbit1 %[tmp], 31, 2f \n" // if lock held, fail immediately
" 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); /* 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.
*
* @param word word to unlock bit 31 in
*/
static inline void cvmx_spinlock_bit_unlock(uint32_t *word)
{
CVMX_SYNCWS;
*word &= ~(1UL << 31) ;
CVMX_SYNCWS;
}
/** ********************************************************************
* Recursive spinlocks
*/
typedef struct {
volatile unsigned int value;
volatile unsigned int core_num;
} cvmx_spinlock_rec_t;
/**
* Initialize a recursive spinlock
*
* @param lock Lock to initialize
*/
static inline void cvmx_spinlock_rec_init(cvmx_spinlock_rec_t *lock)
{
lock->value = CVMX_SPINLOCK_UNLOCKED_VAL;
}
/**
* Return non-zero if the recursive spinlock is currently locked
*
* @param lock Lock to check
* @return Non-zero if locked
*/
static inline int cvmx_spinlock_rec_locked(cvmx_spinlock_rec_t *lock)
{
return (lock->value != CVMX_SPINLOCK_UNLOCKED_VAL);
}
/**
* Unlocks one level of recursive spinlock. Lock is not unlocked
* unless this is the final unlock call for that spinlock
*
* @param lock ptr to recursive spinlock structure
*/
static inline void cvmx_spinlock_rec_unlock(cvmx_spinlock_rec_t *lock);
#ifdef CVMX_SPINLOCK_DEBUG
#define cvmx_spinlock_rec_unlock(x) _int_cvmx_spinlock_rec_unlock((x), __FILE__, __LINE__)
static inline void _int_cvmx_spinlock_rec_unlock(cvmx_spinlock_rec_t *lock, char *filename, int linenum)
#else
static inline void cvmx_spinlock_rec_unlock(cvmx_spinlock_rec_t *lock)
#endif
{
unsigned int temp, result;
int core_num;
core_num = cvmx_get_core_num();
#ifdef CVMX_SPINLOCK_DEBUG
{
if (lock->core_num != core_num)
{
cvmx_dprintf("ERROR: Recursive spinlock release attemped by non-owner! file: %s, line: %d\n", filename, linenum);
return;
}
}
#endif
__asm__ __volatile__(
".set noreorder \n"
" addi %[tmp], %[pid], 0x80 \n"
" sw %[tmp], %[lid] # set lid to invalid value\n"
CVMX_SYNCWS_STR
"1: ll %[tmp], %[val] \n"
" addu %[res], %[tmp], -1 # decrement lock count\n"
" sc %[res], %[val] \n"
" beqz %[res], 1b \n"
" nop \n"
" beq %[tmp], %[res], 2f # res is 1 on successful sc \n"
" nop \n"
" sw %[pid], %[lid] # set lid to pid, only if lock still held\n"
"2: \n"
CVMX_SYNCWS_STR
".set reorder \n"
: [res] "=&r" (result), [tmp] "=&r" (temp), [val] "+m" (lock->value), [lid] "+m" (lock->core_num)
: [pid] "r" (core_num)
: "memory");
#ifdef CVMX_SPINLOCK_DEBUG
{
if (lock->value == ~0UL)
{
cvmx_dprintf("ERROR: Recursive spinlock released too many times! file: %s, line: %d\n", filename, linenum);
}
}
#endif
}
/**
* Takes recursive spinlock for a given core. A core can take the lock multiple
* times, and the lock is released only when the corresponding number of
* unlocks have taken place.
*
* NOTE: This assumes only one thread per core, and that the core ID is used as
* the lock 'key'. (This implementation cannot be generalized to allow
* multiple threads to use the same key (core id) .)
*
* @param lock address of recursive spinlock structure. Note that this is
* distinct from the standard spinlock
*/
static inline void cvmx_spinlock_rec_lock(cvmx_spinlock_rec_t *lock);
#ifdef CVMX_SPINLOCK_DEBUG
#define cvmx_spinlock_rec_lock(x) _int_cvmx_spinlock_rec_lock((x), __FILE__, __LINE__)
static inline void _int_cvmx_spinlock_rec_lock(cvmx_spinlock_rec_t *lock, char *filename, int linenum)
#else
static inline void cvmx_spinlock_rec_lock(cvmx_spinlock_rec_t *lock)
#endif
{
volatile unsigned int tmp;
volatile int core_num;
core_num = cvmx_get_core_num();
__asm__ __volatile__(
".set noreorder \n"
"1: ll %[tmp], %[val] # load the count\n"
" bnez %[tmp], 2f # if count!=zero branch to 2\n"
" addu %[tmp], %[tmp], 1 \n"
" sc %[tmp], %[val] \n"
" beqz %[tmp], 1b # go back if not success\n"
" nop \n"
" j 3f # go to write core_num \n"
"2: lw %[tmp], %[lid] # load the core_num \n"
" bne %[tmp], %[pid], 1b # core_num no match, restart\n"
" nop \n"
" lw %[tmp], %[val] \n"
" addu %[tmp], %[tmp], 1 \n"
" sw %[tmp], %[val] # update the count\n"
"3: sw %[pid], %[lid] # store the core_num\n"
CVMX_SYNCWS_STR
".set reorder \n"
: [tmp] "=&r" (tmp), [val] "+m" (lock->value), [lid] "+m" (lock->core_num)
: [pid] "r" (core_num)
: "memory");
#ifdef CVMX_SPINLOCK_DEBUG
if (lock->core_num != core_num)
{
cvmx_dprintf("cvmx_spinlock_rec_lock: lock taken, but core_num is incorrect. file: %s, line: %d\n", filename, linenum);
}
#endif
}
#ifdef __cplusplus
}
#endif
#endif /* __CVMX_SPINLOCK_H__ */