1 files changed, 163 insertions, 0 deletions

diff --git a/include/asm-cris/arch-v32/spinlock.h b/include/asm-cris/arch-v32/spinlock.h
new file mode 100644
index 000000000000..52df72a62232
--- /dev/null
+++ b/include/asm-cris/arch-v32/spinlock.h
@@ -0,0 +1,163 @@
+#ifndef __ASM_ARCH_SPINLOCK_H
+#define __ASM_ARCH_SPINLOCK_H
+
+#include <asm/system.h>
+
+#define RW_LOCK_BIAS 0x01000000
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 }
+#define spin_lock_init(x)       do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
+
+#define spin_is_locked(x)       (*(volatile signed char *)(&(x)->lock) <= 0)
+#define spin_unlock_wait(x)     do { barrier(); } while(spin_is_locked(x))
+
+extern void cris_spin_unlock(void *l, int val);
+extern void cris_spin_lock(void *l);
+extern int cris_spin_trylock(void* l);
+
+static inline void _raw_spin_unlock(spinlock_t *lock)
+{
+        __asm__ volatile ("move.d %1,%0" \
+                          : "=m" (lock->lock) \
+                          : "r" (1) \
+                          : "memory");
+}
+
+static inline int _raw_spin_trylock(spinlock_t *lock)
+{
+        return cris_spin_trylock((void*)&lock->lock);
+}
+
+static inline void _raw_spin_lock(spinlock_t *lock)
+{
+        cris_spin_lock((void*)&lock->lock);
+}
+
+static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
+{
+  _raw_spin_lock(lock);
+}
+
+/*
+ * Read-write spinlocks, allowing multiple readers
+ * but only one writer.
+ *
+ * NOTE! it is quite common to have readers in interrupts
+ * but no interrupt writers. For those circumstances we
+ * can "mix" irq-safe locks - any writer needs to get a
+ * irq-safe write-lock, but readers can get non-irqsafe
+ * read-locks.
+ */
+typedef struct {
+        spinlock_t lock;
+        volatile int counter;
+#ifdef CONFIG_PREEMPT
+        unsigned int break_lock;
+#endif
+} rwlock_t;
+
+#define RW_LOCK_UNLOCKED (rwlock_t) { {1}, 0 }
+
+#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0)
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define read_can_lock(x) ((int)(x)->counter >= 0)
+
+/**
+ * write_can_lock - would write_trylock() succeed?
+ * @lock: the rwlock in question.
+ */
+#define write_can_lock(x) ((x)->counter == 0)
+
+#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
+
+/* read_lock, read_unlock are pretty straightforward.  Of course it somehow
+ * sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */
+
+static  __inline__ void _raw_read_lock(rwlock_t *rw)
+{
+        unsigned long flags;
+        local_irq_save(flags);
+        _raw_spin_lock(&rw->lock);
+
+        rw->counter++;
+
+        _raw_spin_unlock(&rw->lock);
+        local_irq_restore(flags);
+}
+
+static  __inline__ void _raw_read_unlock(rwlock_t *rw)
+{
+        unsigned long flags;
+        local_irq_save(flags);
+        _raw_spin_lock(&rw->lock);
+
+        rw->counter--;
+
+        _raw_spin_unlock(&rw->lock);
+        local_irq_restore(flags);
+}
+
+/* write_lock is less trivial.  We optimistically grab the lock and check
+ * if we surprised any readers.  If so we release the lock and wait till
+ * they're all gone before trying again
+ *
+ * Also note that we don't use the _irqsave / _irqrestore suffixes here.
+ * If we're called with interrupts enabled and we've got readers (or other
+ * writers) in interrupt handlers someone fucked up and we'd dead-lock
+ * sooner or later anyway.   prumpf */
+
+static  __inline__ void _raw_write_lock(rwlock_t *rw)
+{
+retry:
+        _raw_spin_lock(&rw->lock);
+
+        if(rw->counter != 0) {
+                /* this basically never happens */
+                _raw_spin_unlock(&rw->lock);
+
+                while(rw->counter != 0);
+
+                goto retry;
+        }
+
+        /* got it.  now leave without unlocking */
+        rw->counter = -1; /* remember we are locked */
+}
+
+/* write_unlock is absolutely trivial - we don't have to wait for anything */
+
+static  __inline__ void _raw_write_unlock(rwlock_t *rw)
+{
+        rw->counter = 0;
+        _raw_spin_unlock(&rw->lock);
+}
+
+static  __inline__ int _raw_write_trylock(rwlock_t *rw)
+{
+        _raw_spin_lock(&rw->lock);
+        if (rw->counter != 0) {
+                /* this basically never happens */
+                _raw_spin_unlock(&rw->lock);
+
+                return 0;
+        }
+
+        /* got it.  now leave without unlocking */
+        rw->counter = -1; /* remember we are locked */
+        return 1;
+}
+
+static __inline__ int is_read_locked(rwlock_t *rw)
+{
+        return rw->counter > 0;
+}
+
+static __inline__ int is_write_locked(rwlock_t *rw)
+{
+        return rw->counter < 0;
+}
+
+#endif /* __ASM_ARCH_SPINLOCK_H */