summaryrefslogtreecommitdiffstats
path: root/arch/alpha/include/asm/spinlock.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/alpha/include/asm/spinlock.h')
-rw-r--r--arch/alpha/include/asm/spinlock.h173
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/spinlock.h b/arch/alpha/include/asm/spinlock.h
new file mode 100644
index 00000000000..aeeb125f685
--- /dev/null
+++ b/arch/alpha/include/asm/spinlock.h
@@ -0,0 +1,173 @@
+#ifndef _ALPHA_SPINLOCK_H
+#define _ALPHA_SPINLOCK_H
+
+#include <asm/system.h>
+#include <linux/kernel.h>
+#include <asm/current.h>
+
+/*
+ * Simple spin lock operations. There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ */
+
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_spin_is_locked(x) ((x)->lock != 0)
+#define __raw_spin_unlock_wait(x) \
+ do { cpu_relax(); } while ((x)->lock)
+
+static inline void __raw_spin_unlock(raw_spinlock_t * lock)
+{
+ mb();
+ lock->lock = 0;
+}
+
+static inline void __raw_spin_lock(raw_spinlock_t * lock)
+{
+ long tmp;
+
+ __asm__ __volatile__(
+ "1: ldl_l %0,%1\n"
+ " bne %0,2f\n"
+ " lda %0,1\n"
+ " stl_c %0,%1\n"
+ " beq %0,2f\n"
+ " mb\n"
+ ".subsection 2\n"
+ "2: ldl %0,%1\n"
+ " bne %0,2b\n"
+ " br 1b\n"
+ ".previous"
+ : "=&r" (tmp), "=m" (lock->lock)
+ : "m"(lock->lock) : "memory");
+}
+
+static inline int __raw_spin_trylock(raw_spinlock_t *lock)
+{
+ return !test_and_set_bit(0, &lock->lock);
+}
+
+/***********************************************************/
+
+static inline int __raw_read_can_lock(raw_rwlock_t *lock)
+{
+ return (lock->lock & 1) == 0;
+}
+
+static inline int __raw_write_can_lock(raw_rwlock_t *lock)
+{
+ return lock->lock == 0;
+}
+
+static inline void __raw_read_lock(raw_rwlock_t *lock)
+{
+ long regx;
+
+ __asm__ __volatile__(
+ "1: ldl_l %1,%0\n"
+ " blbs %1,6f\n"
+ " subl %1,2,%1\n"
+ " stl_c %1,%0\n"
+ " beq %1,6f\n"
+ " mb\n"
+ ".subsection 2\n"
+ "6: ldl %1,%0\n"
+ " blbs %1,6b\n"
+ " br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx)
+ : "m" (*lock) : "memory");
+}
+
+static inline void __raw_write_lock(raw_rwlock_t *lock)
+{
+ long regx;
+
+ __asm__ __volatile__(
+ "1: ldl_l %1,%0\n"
+ " bne %1,6f\n"
+ " lda %1,1\n"
+ " stl_c %1,%0\n"
+ " beq %1,6f\n"
+ " mb\n"
+ ".subsection 2\n"
+ "6: ldl %1,%0\n"
+ " bne %1,6b\n"
+ " br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx)
+ : "m" (*lock) : "memory");
+}
+
+static inline int __raw_read_trylock(raw_rwlock_t * lock)
+{
+ long regx;
+ int success;
+
+ __asm__ __volatile__(
+ "1: ldl_l %1,%0\n"
+ " lda %2,0\n"
+ " blbs %1,2f\n"
+ " subl %1,2,%2\n"
+ " stl_c %2,%0\n"
+ " beq %2,6f\n"
+ "2: mb\n"
+ ".subsection 2\n"
+ "6: br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx), "=&r" (success)
+ : "m" (*lock) : "memory");
+
+ return success;
+}
+
+static inline int __raw_write_trylock(raw_rwlock_t * lock)
+{
+ long regx;
+ int success;
+
+ __asm__ __volatile__(
+ "1: ldl_l %1,%0\n"
+ " lda %2,0\n"
+ " bne %1,2f\n"
+ " lda %2,1\n"
+ " stl_c %2,%0\n"
+ " beq %2,6f\n"
+ "2: mb\n"
+ ".subsection 2\n"
+ "6: br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx), "=&r" (success)
+ : "m" (*lock) : "memory");
+
+ return success;
+}
+
+static inline void __raw_read_unlock(raw_rwlock_t * lock)
+{
+ long regx;
+ __asm__ __volatile__(
+ " mb\n"
+ "1: ldl_l %1,%0\n"
+ " addl %1,2,%1\n"
+ " stl_c %1,%0\n"
+ " beq %1,6f\n"
+ ".subsection 2\n"
+ "6: br 1b\n"
+ ".previous"
+ : "=m" (*lock), "=&r" (regx)
+ : "m" (*lock) : "memory");
+}
+
+static inline void __raw_write_unlock(raw_rwlock_t * lock)
+{
+ mb();
+ lock->lock = 0;
+}
+
+#define _raw_spin_relax(lock) cpu_relax()
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
+#endif /* _ALPHA_SPINLOCK_H */