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-rw-r--r--arch/hexagon/include/asm/spinlock.h186
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/spinlock.h b/arch/hexagon/include/asm/spinlock.h
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+++ b/arch/hexagon/include/asm/spinlock.h
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+/*
+ * Spinlock support for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_SPINLOCK_H
+#define _ASM_SPINLOCK_H
+
+#include <asm/irqflags.h>
+
+/*
+ * This file is pulled in for SMP builds.
+ * Really need to check all the barrier stuff for "true" SMP
+ */
+
+/*
+ * Read locks:
+ * - load the lock value
+ * - increment it
+ * - if the lock value is still negative, go back and try again.
+ * - unsuccessful store is unsuccessful. Go back and try again. Loser.
+ * - successful store new lock value if positive -> lock acquired
+ */
+static inline void arch_read_lock(arch_rwlock_t *lock)
+{
+ __asm__ __volatile__(
+ "1: R6 = memw_locked(%0);\n"
+ " { P3 = cmp.ge(R6,#0); R6 = add(R6,#1);}\n"
+ " { if !P3 jump 1b; }\n"
+ " memw_locked(%0,P3) = R6;\n"
+ " { if !P3 jump 1b; }\n"
+ :
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *lock)
+{
+ __asm__ __volatile__(
+ "1: R6 = memw_locked(%0);\n"
+ " R6 = add(R6,#-1);\n"
+ " memw_locked(%0,P3) = R6\n"
+ " if !P3 jump 1b;\n"
+ :
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+
+}
+
+/* I think this returns 0 on fail, 1 on success. */
+static inline int arch_read_trylock(arch_rwlock_t *lock)
+{
+ int temp;
+ __asm__ __volatile__(
+ " R6 = memw_locked(%1);\n"
+ " { %0 = #0; P3 = cmp.ge(R6,#0); R6 = add(R6,#1);}\n"
+ " { if !P3 jump 1f; }\n"
+ " memw_locked(%1,P3) = R6;\n"
+ " { %0 = P3 }\n"
+ "1:\n"
+ : "=&r" (temp)
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+ return temp;
+}
+
+static inline int arch_read_can_lock(arch_rwlock_t *rwlock)
+{
+ return rwlock->lock == 0;
+}
+
+static inline int arch_write_can_lock(arch_rwlock_t *rwlock)
+{
+ return rwlock->lock == 0;
+}
+
+/* Stuffs a -1 in the lock value? */
+static inline void arch_write_lock(arch_rwlock_t *lock)
+{
+ __asm__ __volatile__(
+ "1: R6 = memw_locked(%0)\n"
+ " { P3 = cmp.eq(R6,#0); R6 = #-1;}\n"
+ " { if !P3 jump 1b; }\n"
+ " memw_locked(%0,P3) = R6;\n"
+ " { if !P3 jump 1b; }\n"
+ :
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+}
+
+
+static inline int arch_write_trylock(arch_rwlock_t *lock)
+{
+ int temp;
+ __asm__ __volatile__(
+ " R6 = memw_locked(%1)\n"
+ " { %0 = #0; P3 = cmp.eq(R6,#0); R6 = #-1;}\n"
+ " { if !P3 jump 1f; }\n"
+ " memw_locked(%1,P3) = R6;\n"
+ " %0 = P3;\n"
+ "1:\n"
+ : "=&r" (temp)
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+ return temp;
+
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *lock)
+{
+ smp_mb();
+ lock->lock = 0;
+}
+
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+ __asm__ __volatile__(
+ "1: R6 = memw_locked(%0);\n"
+ " P3 = cmp.eq(R6,#0);\n"
+ " { if !P3 jump 1b; R6 = #1; }\n"
+ " memw_locked(%0,P3) = R6;\n"
+ " { if !P3 jump 1b; }\n"
+ :
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+ smp_mb();
+ lock->lock = 0;
+}
+
+static inline unsigned int arch_spin_trylock(arch_spinlock_t *lock)
+{
+ int temp;
+ __asm__ __volatile__(
+ " R6 = memw_locked(%1);\n"
+ " P3 = cmp.eq(R6,#0);\n"
+ " { if !P3 jump 1f; R6 = #1; %0 = #0; }\n"
+ " memw_locked(%1,P3) = R6;\n"
+ " %0 = P3;\n"
+ "1:\n"
+ : "=&r" (temp)
+ : "r" (&lock->lock)
+ : "memory", "r6", "p3"
+ );
+ return temp;
+}
+
+/*
+ * SMP spinlocks are intended to allow only a single CPU at the lock
+ */
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+#define arch_spin_unlock_wait(lock) \
+ do {while (arch_spin_is_locked(lock)) cpu_relax(); } while (0)
+#define arch_spin_is_locked(x) ((x)->lock != 0)
+
+#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
+
+#endif