1 files changed, 269 insertions, 0 deletions

diff --git a/include/asm-powerpc/spinlock.h b/include/asm-powerpc/spinlock.h
new file mode 100644
index 000000000000..caa4b14e0e94
--- /dev/null
+++ b/include/asm-powerpc/spinlock.h
@@ -0,0 +1,269 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+/*
+ * Simple spin lock operations.  
+ *
+ * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
+ * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
+ * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
+ *      Rework to support virtual processors
+ *
+ * Type of int is used as a full 64b word is not necessary.
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
+ */
+#ifdef CONFIG_PPC64
+#include <asm/paca.h>
+#include <asm/hvcall.h>
+#include <asm/iseries/hv_call.h>
+#endif
+#include <asm/asm-compat.h>
+#include <asm/synch.h>
+
+#define __raw_spin_is_locked(x)         ((x)->slock != 0)
+
+#ifdef CONFIG_PPC64
+/* use 0x800000yy when locked, where yy == CPU number */
+#define LOCK_TOKEN      (*(u32 *)(&get_paca()->lock_token))
+#else
+#define LOCK_TOKEN      1
+#endif
+
+/*
+ * This returns the old value in the lock, so we succeeded
+ * in getting the lock if the return value is 0.
+ */
+static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock)
+{
+        unsigned long tmp, token;
+
+        token = LOCK_TOKEN;
+        __asm__ __volatile__(
+"1:     lwarx           %0,0,%2         # __spin_trylock\n\
+        cmpwi           0,%0,0\n\
+        bne-            2f\n\
+        stwcx.          %1,0,%2\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp)
+        : "r" (token), "r" (&lock->slock)
+        : "cr0", "memory");
+
+        return tmp;
+}
+
+static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock)
+{
+        return __spin_trylock(lock) == 0;
+}
+
+/*
+ * On a system with shared processors (that is, where a physical
+ * processor is multiplexed between several virtual processors),
+ * there is no point spinning on a lock if the holder of the lock
+ * isn't currently scheduled on a physical processor.  Instead
+ * we detect this situation and ask the hypervisor to give the
+ * rest of our timeslice to the lock holder.
+ *
+ * So that we can tell which virtual processor is holding a lock,
+ * we put 0x80000000 | smp_processor_id() in the lock when it is
+ * held.  Conveniently, we have a word in the paca that holds this
+ * value.
+ */
+
+#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
+/* We only yield to the hypervisor if we are in shared processor mode */
+#define SHARED_PROCESSOR (get_paca()->lppaca.shared_proc)
+extern void __spin_yield(raw_spinlock_t *lock);
+extern void __rw_yield(raw_rwlock_t *lock);
+#else /* SPLPAR || ISERIES */
+#define __spin_yield(x) barrier()
+#define __rw_yield(x)   barrier()
+#define SHARED_PROCESSOR        0
+#endif
+
+static void __inline__ __raw_spin_lock(raw_spinlock_t *lock)
+{
+        while (1) {
+                if (likely(__spin_trylock(lock) == 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __spin_yield(lock);
+                } while (unlikely(lock->slock != 0));
+                HMT_medium();
+        }
+}
+
+static void __inline__ __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
+{
+        unsigned long flags_dis;
+
+        while (1) {
+                if (likely(__spin_trylock(lock) == 0))
+                        break;
+                local_save_flags(flags_dis);
+                local_irq_restore(flags);
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __spin_yield(lock);
+                } while (unlikely(lock->slock != 0));
+                HMT_medium();
+                local_irq_restore(flags_dis);
+        }
+}
+
+static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock)
+{
+        __asm__ __volatile__(SYNC_ON_SMP"       # __raw_spin_unlock"
+                             : : :"memory");
+        lock->slock = 0;
+}
+
+#ifdef CONFIG_PPC64
+extern void __raw_spin_unlock_wait(raw_spinlock_t *lock);
+#else
+#define __raw_spin_unlock_wait(lock) \
+        do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
+#endif
+
+/*
+ * 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.
+ */
+
+#define __raw_read_can_lock(rw)         ((rw)->lock >= 0)
+#define __raw_write_can_lock(rw)        (!(rw)->lock)
+
+#ifdef CONFIG_PPC64
+#define __DO_SIGN_EXTEND        "extsw  %0,%0\n"
+#define WRLOCK_TOKEN            LOCK_TOKEN      /* it's negative */
+#else
+#define __DO_SIGN_EXTEND
+#define WRLOCK_TOKEN            (-1)
+#endif
+
+/*
+ * This returns the old value in the lock + 1,
+ * so we got a read lock if the return value is > 0.
+ */
+static long __inline__ __read_trylock(raw_rwlock_t *rw)
+{
+        long tmp;
+
+        __asm__ __volatile__(
+"1:     lwarx           %0,0,%1         # read_trylock\n"
+        __DO_SIGN_EXTEND
+"       addic.          %0,%0,1\n\
+        ble-            2f\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.          %0,0,%1\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp)
+        : "r" (&rw->lock)
+        : "cr0", "xer", "memory");
+
+        return tmp;
+}
+
+/*
+ * This returns the old value in the lock,
+ * so we got the write lock if the return value is 0.
+ */
+static __inline__ long __write_trylock(raw_rwlock_t *rw)
+{
+        long tmp, token;
+
+        token = WRLOCK_TOKEN;
+        __asm__ __volatile__(
+"1:     lwarx           %0,0,%2 # write_trylock\n\
+        cmpwi           0,%0,0\n\
+        bne-            2f\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.          %1,0,%2\n\
+        bne-            1b\n\
+        isync\n\
+2:"     : "=&r" (tmp)
+        : "r" (token), "r" (&rw->lock)
+        : "cr0", "memory");
+
+        return tmp;
+}
+
+static void __inline__ __raw_read_lock(raw_rwlock_t *rw)
+{
+        while (1) {
+                if (likely(__read_trylock(rw) > 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __rw_yield(rw);
+                } while (unlikely(rw->lock < 0));
+                HMT_medium();
+        }
+}
+
+static void __inline__ __raw_write_lock(raw_rwlock_t *rw)
+{
+        while (1) {
+                if (likely(__write_trylock(rw) == 0))
+                        break;
+                do {
+                        HMT_low();
+                        if (SHARED_PROCESSOR)
+                                __rw_yield(rw);
+                } while (unlikely(rw->lock != 0));
+                HMT_medium();
+        }
+}
+
+static int __inline__ __raw_read_trylock(raw_rwlock_t *rw)
+{
+        return __read_trylock(rw) > 0;
+}
+
+static int __inline__ __raw_write_trylock(raw_rwlock_t *rw)
+{
+        return __write_trylock(rw) == 0;
+}
+
+static void __inline__ __raw_read_unlock(raw_rwlock_t *rw)
+{
+        long tmp;
+
+        __asm__ __volatile__(
+        "eieio                          # read_unlock\n\
+1:      lwarx           %0,0,%1\n\
+        addic           %0,%0,-1\n"
+        PPC405_ERR77(0,%1)
+"       stwcx.          %0,0,%1\n\
+        bne-            1b"
+        : "=&r"(tmp)
+        : "r"(&rw->lock)
+        : "cr0", "memory");
+}
+
+static __inline__ void __raw_write_unlock(raw_rwlock_t *rw)
+{
+        __asm__ __volatile__(SYNC_ON_SMP"       # write_unlock"
+                             : : :"memory");
+        rw->lock = 0;
+}
+
+#endif /* __ASM_SPINLOCK_H */