[PATCH V2 3/5] csky: Move to generic ticket-spinlock

From: guoren
Date: Fri Mar 18 2022 - 23:55:46 EST


From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

There is no benefit from custom implementation for ticket-spinlock,
so move to generic ticket-spinlock for easy maintenance.

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
---
arch/csky/include/asm/Kbuild | 3 +-
arch/csky/include/asm/spinlock.h | 89 --------------------------
arch/csky/include/asm/spinlock_types.h | 27 --------
3 files changed, 2 insertions(+), 117 deletions(-)
delete mode 100644 arch/csky/include/asm/spinlock.h
delete mode 100644 arch/csky/include/asm/spinlock_types.h

diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 904a18a818be..056625619c19 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += asm-offsets.h
generic-y += extable.h
generic-y += gpio.h
generic-y += kvm_para.h
-generic-y += qrwlock.h
+generic-y += spinlock_types.h
+generic-y += spinlock.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h
deleted file mode 100644
index 69f5aa249c5f..000000000000
--- a/arch/csky/include/asm/spinlock.h
+++ /dev/null
@@ -1,89 +0,0 @@
-/* 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 */
diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h
deleted file mode 100644
index db87a12c3827..000000000000
--- a/arch/csky/include/asm/spinlock_types.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#ifndef __ASM_CSKY_SPINLOCK_TYPES_H
-#define __ASM_CSKY_SPINLOCK_TYPES_H
-
-#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
-# error "please don't include this file directly"
-#endif
-
-#define TICKET_NEXT 16
-
-typedef struct {
- union {
- u32 lock;
- struct __raw_tickets {
- /* little endian */
- u16 owner;
- u16 next;
- } tickets;
- };
-} arch_spinlock_t;
-
-#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } }
-
-#include <asm-generic/qrwlock_types.h>
-
-#endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
--
2.25.1