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Subject: [PATCH v3 7/7] csky: Move to generic ticket-spinlock
Date:   Thu, 14 Apr 2022 15:02:14 -0700
Message-Id: <20220414220214.24556-8-palmer@rivosinc.com>
In-Reply-To: <20220414220214.24556-1-palmer@rivosinc.com>
References: <20220414220214.24556-1-palmer@rivosinc.com>
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Cc:     peterz@infradead.org, mingo@redhat.com,
        Will Deacon <will@kernel.org>, longman@redhat.com,
        boqun.feng@gmail.com, jonas@southpole.se,
        stefan.kristiansson@saunalahti.fi,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>, aou@eecs.berkeley.edu,
        Arnd Bergmann <arnd@arndb.de>, macro@orcam.me.uk,
        Greg KH <gregkh@linuxfoundation.org>,
        sudipm.mukherjee@gmail.com, wangkefeng.wang@huawei.com,
        jszhang@kernel.org, linux-csky@vger.kernel.org,
        linux-kernel@vger.kernel.org, openrisc@lists.librecores.org,
        linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org,
        Guo Ren <guoren@linux.alibaba.com>,
        Palmer Dabbelt <palmer@rivosinc.com>
From:   Palmer Dabbelt <palmer@rivosinc.com>
To:     Arnd Bergmann <arnd@arndb.de>, heiko@sntech.de, guoren@kernel.org,
        shorne@gmail.com
Precedence: bulk

From: Guo Ren <guoren@linux.alibaba.com>

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@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 arch/csky/include/asm/Kbuild           |  3 +
 arch/csky/include/asm/spinlock.h       | 89 --------------------------
 arch/csky/include/asm/spinlock_types.h | 27 --------
 3 files changed, 3 insertions(+), 116 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 888248235c23..103207a58f97 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -3,7 +3,10 @@ generic-y += asm-offsets.h
 generic-y += extable.h
 generic-y += gpio.h
 generic-y += kvm_para.h
+generic-y += spinlock.h
+generic-y += spinlock_types.h
 generic-y += qrwlock.h
+generic-y += qrwlock_types.h
 generic-y += parport.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 */
-- 
2.34.1