1 files changed, 161 insertions, 0 deletions
diff --git a/arch/tile/include/asm/spinlock_64.h b/arch/tile/include/asm/spinlock_64.h
new file mode 100644
index 00000000..5f8b6a09
--- /dev/null
+++ b/arch/tile/include/asm/spinlock_64.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright 2011 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * 64-bit SMP ticket spinlocks, allowing only a single CPU anywhere
+ * (the type definitions are in asm/spinlock_types.h)
+ */
+
+#ifndef _ASM_TILE_SPINLOCK_64_H
+#define _ASM_TILE_SPINLOCK_64_H
+
+/* Shifts and masks for the various fields in "lock". */
+#define __ARCH_SPIN_CURRENT_SHIFT	17
+#define __ARCH_SPIN_NEXT_MASK		0x7fff
+#define __ARCH_SPIN_NEXT_OVERFLOW	0x8000
+
+/*
+ * Return the "current" portion of a ticket lock value,
+ * i.e. the number that currently owns the lock.
+ */
+static inline int arch_spin_current(u32 val)
+{
+	return val >> __ARCH_SPIN_CURRENT_SHIFT;
+}
+
+/*
+ * Return the "next" portion of a ticket lock value,
+ * i.e. the number that the next task to try to acquire the lock will get.
+ */
+static inline int arch_spin_next(u32 val)
+{
+	return val & __ARCH_SPIN_NEXT_MASK;
+}
+
+/* The lock is locked if a task would have to wait to get it. */
+static inline int arch_spin_is_locked(arch_spinlock_t *lock)
+{
+	u32 val = lock->lock;
+	return arch_spin_current(val) != arch_spin_next(val);
+}
+
+/* Bump the current ticket so the next task owns the lock. */
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+	wmb();  /* guarantee anything modified under the lock is visible */
+	__insn_fetchadd4(&lock->lock, 1U << __ARCH_SPIN_CURRENT_SHIFT);
+}
+
+void arch_spin_unlock_wait(arch_spinlock_t *lock);
+
+void arch_spin_lock_slow(arch_spinlock_t *lock, u32 val);
+
+/* Grab the "next" ticket number and bump it atomically.
+ * If the current ticket is not ours, go to the slow path.
+ * We also take the slow path if the "next" value overflows.
+ */
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+	u32 val = __insn_fetchadd4(&lock->lock, 1);
+	u32 ticket = val & (__ARCH_SPIN_NEXT_MASK | __ARCH_SPIN_NEXT_OVERFLOW);
+	if (unlikely(arch_spin_current(val) != ticket))
+		arch_spin_lock_slow(lock, ticket);
+}
+
+/* Try to get the lock, and return whether we succeeded. */
+int arch_spin_trylock(arch_spinlock_t *lock);
+
+/* We cannot take an interrupt after getting a ticket, so don't enable them. */
+#define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
+
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * We use fetchadd() for readers, and fetchor() with the sign bit
+ * for writers.
+ */
+
+#define __WRITE_LOCK_BIT (1 << 31)
+
+static inline int arch_write_val_locked(int val)
+{
+	return val < 0;  /* Optimize "val & __WRITE_LOCK_BIT". */
+}
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int arch_read_can_lock(arch_rwlock_t *rw)
+{
+	return !arch_write_val_locked(rw->lock);
+}
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+static inline int arch_write_can_lock(arch_rwlock_t *rw)
+{
+	return rw->lock == 0;
+}
+
+extern void __read_lock_failed(arch_rwlock_t *rw);
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+	u32 val = __insn_fetchaddgez4(&rw->lock, 1);
+	if (unlikely(arch_write_val_locked(val)))
+		__read_lock_failed(rw);
+}
+
+extern void __write_lock_failed(arch_rwlock_t *rw, u32 val);
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+	u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT);
+	if (unlikely(val != 0))
+		__write_lock_failed(rw, val);
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+	__insn_mf();
+	__insn_fetchadd4(&rw->lock, -1);
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+	__insn_mf();
+	__insn_exch4(&rw->lock, 0);  /* Avoid waiting in the write buffer. */
+}
+
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+	return !arch_write_val_locked(__insn_fetchaddgez4(&rw->lock, 1));
+}
+
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+	u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT);
+	if (likely(val == 0))
+		return 1;
+	if (!arch_write_val_locked(val))
+		__insn_fetchand4(&rw->lock, ~__WRITE_LOCK_BIT);
+	return 0;
+}
+
+#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
+#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
+
+#endif /* _ASM_TILE_SPINLOCK_64_H */