1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef __ASM_CSKY_SPINLOCK_H
4 #define __ASM_CSKY_SPINLOCK_H
5 
6 #include <linux/spinlock_types.h>
7 #include <asm/barrier.h>
8 
9 /*
10  * Ticket-based spin-locking.
11  */
arch_spin_lock(arch_spinlock_t * lock)12 static inline void arch_spin_lock(arch_spinlock_t *lock)
13 {
14 	arch_spinlock_t lockval;
15 	u32 ticket_next = 1 << TICKET_NEXT;
16 	u32 *p = &lock->lock;
17 	u32 tmp;
18 
19 	asm volatile (
20 		"1:	ldex.w		%0, (%2) \n"
21 		"	mov		%1, %0	 \n"
22 		"	add		%0, %3	 \n"
23 		"	stex.w		%0, (%2) \n"
24 		"	bez		%0, 1b   \n"
25 		: "=&r" (tmp), "=&r" (lockval)
26 		: "r"(p), "r"(ticket_next)
27 		: "cc");
28 
29 	while (lockval.tickets.next != lockval.tickets.owner)
30 		lockval.tickets.owner = READ_ONCE(lock->tickets.owner);
31 
32 	smp_mb();
33 }
34 
arch_spin_trylock(arch_spinlock_t * lock)35 static inline int arch_spin_trylock(arch_spinlock_t *lock)
36 {
37 	u32 tmp, contended, res;
38 	u32 ticket_next = 1 << TICKET_NEXT;
39 	u32 *p = &lock->lock;
40 
41 	do {
42 		asm volatile (
43 		"	ldex.w		%0, (%3)   \n"
44 		"	movi		%2, 1	   \n"
45 		"	rotli		%1, %0, 16 \n"
46 		"	cmpne		%1, %0     \n"
47 		"	bt		1f         \n"
48 		"	movi		%2, 0	   \n"
49 		"	add		%0, %0, %4 \n"
50 		"	stex.w		%0, (%3)   \n"
51 		"1:				   \n"
52 		: "=&r" (res), "=&r" (tmp), "=&r" (contended)
53 		: "r"(p), "r"(ticket_next)
54 		: "cc");
55 	} while (!res);
56 
57 	if (!contended)
58 		smp_mb();
59 
60 	return !contended;
61 }
62 
arch_spin_unlock(arch_spinlock_t * lock)63 static inline void arch_spin_unlock(arch_spinlock_t *lock)
64 {
65 	smp_mb();
66 	WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1);
67 }
68 
arch_spin_value_unlocked(arch_spinlock_t lock)69 static inline int arch_spin_value_unlocked(arch_spinlock_t lock)
70 {
71 	return lock.tickets.owner == lock.tickets.next;
72 }
73 
arch_spin_is_locked(arch_spinlock_t * lock)74 static inline int arch_spin_is_locked(arch_spinlock_t *lock)
75 {
76 	return !arch_spin_value_unlocked(READ_ONCE(*lock));
77 }
78 
arch_spin_is_contended(arch_spinlock_t * lock)79 static inline int arch_spin_is_contended(arch_spinlock_t *lock)
80 {
81 	struct __raw_tickets tickets = READ_ONCE(lock->tickets);
82 
83 	return (tickets.next - tickets.owner) > 1;
84 }
85 #define arch_spin_is_contended	arch_spin_is_contended
86 
87 #include <asm/qrwlock.h>
88 
89 #endif /* __ASM_CSKY_SPINLOCK_H */
90