90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/* 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 */
|