Viewing file:  spinlock.h (1.85 KB) -rw-r--r--
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_CSKY_SPINLOCK_H
#define __ASM_CSKY_SPINLOCK_H
#include <linux/spinlock_types.h>
#include <asm/barrier.h>
/*
* Ticket-based spin-locking.
*/
static inline void arch_spin_lock(arch_spinlock_t *lock)
{
arch_spinlock_t lockval;
u32 ticket_next = 1 << TICKET_NEXT;
u32 *p = &lock->lock;
u32 tmp;
asm volatile (
"1: ldex.w %0, (%2) \n"
" mov %1, %0 \n"
" add %0, %3 \n"
" stex.w %0, (%2) \n"
" bez %0, 1b \n"
: "=&r" (tmp), "=&r" (lockval)
: "r"(p), "r"(ticket_next)
: "cc");
while (lockval.tickets.next != lockval.tickets.owner)
lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
smp_mb();
}
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
u32 tmp, contended, res;
u32 ticket_next = 1 << TICKET_NEXT;
u32 *p = &lock->lock;
do {
asm volatile (
" ldex.w %0, (%3) \n"
" movi %2, 1 \n"
" rotli %1, %0, 16 \n"
" cmpne %1, %0 \n"
" bt 1f \n"
" movi %2, 0 \n"
" add %0, %0, %4 \n"
" stex.w %0, (%3) \n"
"1: \n"
: "=&r" (res), "=&r" (tmp), "=&r" (contended)
: "r"(p), "r"(ticket_next)
: "cc");
} while (!res);
if (!contended)
smp_mb();
return !contended;
}
static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
smp_mb();
WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
}
static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
{
return lock.tickets.owner == lock.tickets.next;
}
static inline int arch_spin_is_locked(arch_spinlock_t *lock)
{
return !arch_spin_value_unlocked(READ_ONCE(*lock));
}
static inline int arch_spin_is_contended(arch_spinlock_t *lock)
{
struct __raw_tickets tickets = READ_ONCE(lock->tickets);
return (tickets.next - tickets.owner) > 1;
}
#define arch_spin_is_contended arch_spin_is_contended
#include <asm/qrwlock.h>
#endif /* __ASM_CSKY_SPINLOCK_H */
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