Hexagon: Add locking types and functions

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 228 insertions, 0 deletions

diff --git a/arch/hexagon/include/asm/spinlock.h b/arch/hexagon/include/asm/spinlock.h
new file mode 100644
index 000000000000..168a920485a8
--- /dev/null
+++ b/arch/hexagon/include/asm/spinlock.h
@@ -0,0 +1,186 @@
+/*
+ * 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
diff --git a/arch/hexagon/include/asm/spinlock_types.h b/arch/hexagon/include/asm/spinlock_types.h
new file mode 100644
index 000000000000..5e937af1c4ad
--- /dev/null
+++ b/arch/hexagon/include/asm/spinlock_types.h
@@ -0,0 +1,42 @@
+/*
+ * 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_TYPES_H
+#define _ASM_SPINLOCK_TYPES_H
+
+#include <linux/version.h>
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+# error "please don't include this file directly"
+#endif
+
+typedef struct {
+        volatile unsigned int lock;
+} arch_spinlock_t;
+
+#define __ARCH_SPIN_LOCK_UNLOCKED       { 0 }
+
+typedef struct {
+        volatile unsigned int lock;
+} arch_rwlock_t;
+
+#define __ARCH_RW_LOCK_UNLOCKED         { 0 }
+
+#endif