105 lines
3.9 KiB
C
105 lines
3.9 KiB
C
/****************************************************************************
|
|
* arch/xtensa/include/spinlock.h
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifndef __ARCH_XTENSA_INCLUDE_SPINLOCK_H
|
|
#define __ARCH_XTENSA_INCLUDE_SPINLOCK_H
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#ifndef __ASSEMBLY__
|
|
# include <stdint.h>
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
#define SP_UNLOCKED 0 /* The Un-locked state */
|
|
#define SP_LOCKED 1 /* The Locked state */
|
|
|
|
/****************************************************************************
|
|
* Public Types
|
|
****************************************************************************/
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
/* The Type of a spinlock.
|
|
*
|
|
* This must be a uint32_ because it will be set using S32C1I instruction.
|
|
* That instruction atomically stores to a memory location only if its
|
|
* current value is the expected one. The state register (SCOMPARE1) is
|
|
* used to provide the additional comparison operand. Some implementations
|
|
* also have a state register (ATOMCTL) for further control of the atomic
|
|
* operation in cache and on the PIF bus.
|
|
*/
|
|
|
|
typedef uint32_t spinlock_t;
|
|
|
|
/****************************************************************************
|
|
* Public Function Prototypes
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: up_testset
|
|
*
|
|
* Description:
|
|
* Perform an atomic test and set operation on the provided spinlock.
|
|
*
|
|
* This function must be provided via the architecture-specific logic.
|
|
*
|
|
* Input Parameters:
|
|
* lock - The address of spinlock object.
|
|
*
|
|
* Returned Value:
|
|
* The spinlock is always locked upon return. The value of previous value
|
|
* of the spinlock variable is returned, either SP_LOCKED if the spinlock
|
|
* as previously locked (meaning that the test-and-set operation failed to
|
|
* obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
|
|
* (meaning that we successfully obtained the lock)
|
|
*
|
|
****************************************************************************/
|
|
|
|
#if defined(CONFIG_SPINLOCK)
|
|
static inline_function spinlock_t up_testset(volatile spinlock_t *lock)
|
|
{
|
|
/* Perform the 32-bit compare and set operation */
|
|
|
|
spinlock_t ret;
|
|
|
|
__asm__ __volatile__
|
|
(
|
|
"WSR %2, SCOMPARE1\n" /* Initialize SCOMPARE1 */
|
|
"S32C1I %0, %1, 0\n" /* Store the compare value into the lock,
|
|
* if the lock is the same as compare1.
|
|
* Otherwise, no write-access */
|
|
: "=r"(ret) : "r"(lock), "r"(SP_UNLOCKED), "0"(SP_LOCKED)
|
|
);
|
|
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
/* See prototype in nuttx/include/nuttx/spinlock.h */
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
#endif /* __ARCH_XTENSA_INCLUDE_SPINLOCK_H */
|