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#ifndef __CB_BDK_SPINLOCK_H__
#define __CB_BDK_SPINLOCK_H__
/***********************license start***********************************
* Copyright (c) 2003-2017 Cavium Inc. (support@cavium.com). All rights
* reserved.
*
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* * Neither the name of Cavium Inc. nor the names of
* its contributors may be used to endorse or promote products
* derived from this software without specific prior written
* permission.
*
* This Software, including technical data, may be subject to U.S. export
* control laws, including the U.S. Export Administration Act and its
* associated regulations, and may be subject to export or import
* regulations in other countries.
*
* TO THE MAXIMUM EXTENT PERMITTED BY LAW, THE SOFTWARE IS PROVIDED "AS IS"
* AND WITH ALL FAULTS AND CAVIUM INC. MAKES NO PROMISES, REPRESENTATIONS OR
* WARRANTIES, EITHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, WITH RESPECT
* TO THE SOFTWARE, INCLUDING ITS CONDITION, ITS CONFORMITY TO ANY
* REPRESENTATION OR DESCRIPTION, OR THE EXISTENCE OF ANY LATENT OR PATENT
* DEFECTS, AND CAVIUM SPECIFICALLY DISCLAIMS ALL IMPLIED (IF ANY) WARRANTIES
* OF TITLE, MERCHANTABILITY, NONINFRINGEMENT, FITNESS FOR A PARTICULAR
* PURPOSE, LACK OF VIRUSES, ACCURACY OR COMPLETENESS, QUIET ENJOYMENT,
* QUIET POSSESSION OR CORRESPONDENCE TO DESCRIPTION. THE ENTIRE RISK
* ARISING OUT OF USE OR PERFORMANCE OF THE SOFTWARE LIES WITH YOU.
***********************license end**************************************/
/**
* @file
*
* Implementation of spinlocks.
*
* <hr>$Revision: 49448 $<hr>
*
* @addtogroup hal
* @{
*/
/**
* Spinlocks
*/
typedef union
{
uint64_t combined;
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
uint32_t ticket;
uint32_t serving;
#else
uint32_t serving;
uint32_t ticket;
#endif
} s;
} bdk_spinlock_t;
/**
* Initialize a spinlock
*
* @param lock Lock to initialize
*/
static inline void bdk_spinlock_init(bdk_spinlock_t *lock)
{
asm volatile ("str xzr, [%[b]]"
: "+m" (lock->combined)
: [b] "r" (&lock->combined)
: "memory");
}
/**
* Releases lock
*
* @param lock pointer to lock structure
*/
static inline void bdk_spinlock_unlock(bdk_spinlock_t *lock) __attribute__ ((always_inline));
static inline void bdk_spinlock_unlock(bdk_spinlock_t *lock)
{
/* Implies a release */
asm volatile ("stlr %w[v], [%[b]]"
: "+m" (lock->s.serving)
: [v] "r" (lock->s.serving + 1), [b] "r" (&lock->s.serving)
: "memory");
}
/**
* Gets lock, spins until lock is taken
*
* @param lock pointer to lock structure
*/
static inline void bdk_spinlock_lock(bdk_spinlock_t *lock) __attribute__ ((always_inline));
static inline void bdk_spinlock_lock(bdk_spinlock_t *lock)
{
uint64_t combined;
uint32_t ticket;
uint32_t serving;
asm volatile (
"mov %x[serving], 1<<32 \n"
"ldadda %x[serving], %x[combined], [%[ptr]] \n"
"and %x[serving], %x[combined], 0xffffffff \n"
"lsr %x[ticket], %x[combined], 32 \n"
"cmp %x[ticket], %x[serving] \n"
"b.eq 1f \n"
"sevl \n"
"2: wfe \n"
"ldxr %w[serving], [%[ptr2]] \n"
"cmp %x[ticket], %x[serving] \n"
"b.ne 2b \n"
"1: \n"
: [serving] "=&r" (serving), [ticket] "=&r" (ticket), [combined] "=&r" (combined), "+m" (lock->combined)
: [ptr] "r" (&lock->combined), [ptr2] "r" (&lock->s.serving)
: "memory"
);
}
/**
* Trys to get the lock, failing if we can't get it immediately
*
* @param lock pointer to lock structure
*/
static inline int bdk_spinlock_trylock(bdk_spinlock_t *lock) __attribute__ ((always_inline));
static inline int bdk_spinlock_trylock(bdk_spinlock_t *lock)
{
uint64_t combined = *(volatile uint64_t *)&lock->combined;
uint32_t ticket = combined >> 32;
uint32_t serving = (uint32_t)combined;
if (ticket != serving)
return -1;
uint64_t new_combined = combined + (1ull << 32);
bool success = bdk_atomic_compare_and_store64(&lock->combined, combined, new_combined);
return success ? 0 : -1;
}
/** @} */
#endif /* !__CB_BDK_SPINLOCK_H__ */
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