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#ifndef _M68K_SEMAPHORE_H
#define _M68K_SEMAPHORE_H
#include <linux/config.h>
#include <linux/linkage.h>
#include <asm/current.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* m68k version by Andreas Schwab
*/
struct semaphore {
atomic_t count;
unsigned long owner, owner_depth;
atomic_t waking;
struct wait_queue * wait;
};
/*
* Because we want the non-contention case to be
* fast, we save the stack pointer into the "owner"
* field, and to get the true task pointer we have
* to do the bit masking. That moves the masking
* operation into the slow path.
*/
#define semaphore_owner(sem) \
((struct task_struct *)((2*PAGE_MASK) & (sem)->owner))
#define MUTEX ((struct semaphore) { ATOMIC_INIT(1), 0, 0, ATOMIC_INIT(0), NULL })
#define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), 0, 1, ATOMIC_INIT(0), NULL })
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
#define sema_init(sem, val) atomic_set(&((sem)->count), val)
static inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
{
#ifndef CONFIG_RMW_INSNS
unsigned long flags;
int ret = 0;
save_flags(flags);
cli();
if (atomic_read(&sem->waking) > 0 || (owner_depth && semaphore_owner(sem) == tsk)) {
sem->owner = (unsigned long)tsk;
sem->owner_depth++;
atomic_dec(&sem->waking);
ret = 1;
}
restore_flags(flags);
#else
int ret, tmp;
__asm__ __volatile__
("1: movel %2,%0\n"
" jeq 3f\n"
"2: movel %0,%1\n"
" subql #1,%1\n"
" casl %0,%1,%2\n"
" jeq 3f\n"
" tstl %0\n"
" jne 2b\n"
"3:"
: "=d" (ret), "=d" (tmp), "=m" (sem->waking));
ret |= ((sem->owner_depth != 0) && (semaphore_owner(sem) == tsk));
if (ret) {
sem->owner = (unsigned long)tsk;
sem->owner_depth++;
}
#endif
return ret;
}
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/m68k/lib/semaphore.S
*/
extern inline void down(struct semaphore * sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
__asm__ __volatile__(
"| atomic down operation\n\t"
"subql #1,%0@\n\t"
"jmi 2f\n\t"
"movel %%sp,4(%0)\n"
"movel #1,8(%0)\n\t"
"1:\n"
".section .text.lock,\"ax\"\n"
".even\n"
"2:\tpea 1b\n\t"
"jbra __down_failed\n"
".previous"
: /* no outputs */
: "a" (sem1)
: "memory");
}
extern inline int down_interruptible(struct semaphore * sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
register int result __asm__ ("%d0");
__asm__ __volatile__(
"| atomic interruptible down operation\n\t"
"subql #1,%1@\n\t"
"jmi 2f\n\t"
"movel %%sp,4(%1)\n"
"moveql #1,%0\n"
"movel %0,8(%1)\n"
"clrl %0\n"
"1:\n"
".section .text.lock,\"ax\"\n"
".even\n"
"2:\tpea 1b\n\t"
"jbra __down_failed_interruptible\n"
".previous"
: "=d" (result)
: "a" (sem1)
: "%d0", "memory");
return result;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
extern inline void up(struct semaphore * sem)
{
register struct semaphore *sem1 __asm__ ("%a1") = sem;
__asm__ __volatile__(
"| atomic up operation\n\t"
"subql #1,8(%0)\n\t"
"addql #1,%0@\n\t"
"jle 2f\n"
"1:\n"
".section .text.lock,\"ax\"\n"
".even\n"
"2:\tpea 1b\n\t"
"jbra __up_wakeup\n"
".previous"
: /* no outputs */
: "a" (sem1)
: "memory");
}
#endif
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