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-rw-r--r--include/asm-mips/spinlock.h299
1 files changed, 299 insertions, 0 deletions
diff --git a/include/asm-mips/spinlock.h b/include/asm-mips/spinlock.h
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+++ b/include/asm-mips/spinlock.h
@@ -0,0 +1,299 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1999, 2000 by Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ */
+#ifndef _ASM_SPINLOCK_H
+#define _ASM_SPINLOCK_H
+
+#include <linux/config.h>
+#include <asm/war.h>
+
+/*
+ * Your basic SMP spinlocks, allowing only a single CPU anywhere
+ */
+
+typedef struct {
+ volatile unsigned int lock;
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+} spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
+
+#define spin_lock_init(x) do { (x)->lock = 0; } while(0)
+
+#define spin_is_locked(x) ((x)->lock != 0)
+#define spin_unlock_wait(x) do { barrier(); } while ((x)->lock)
+#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+
+/*
+ * 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.
+ */
+
+static inline void _raw_spin_lock(spinlock_t *lock)
+{
+ unsigned int tmp;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_spin_lock \n"
+ "1: ll %1, %2 \n"
+ " bnez %1, 1b \n"
+ " li %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqzl %1, 1b \n"
+ " nop \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (lock->lock), "=&r" (tmp)
+ : "m" (lock->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_spin_lock \n"
+ "1: ll %1, %2 \n"
+ " bnez %1, 1b \n"
+ " li %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqz %1, 1b \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (lock->lock), "=&r" (tmp)
+ : "m" (lock->lock)
+ : "memory");
+ }
+}
+
+static inline void _raw_spin_unlock(spinlock_t *lock)
+{
+ __asm__ __volatile__(
+ " .set noreorder # _raw_spin_unlock \n"
+ " sync \n"
+ " sw $0, %0 \n"
+ " .set\treorder \n"
+ : "=m" (lock->lock)
+ : "m" (lock->lock)
+ : "memory");
+}
+
+static inline unsigned int _raw_spin_trylock(spinlock_t *lock)
+{
+ unsigned int temp, res;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_spin_trylock \n"
+ "1: ll %0, %3 \n"
+ " ori %2, %0, 1 \n"
+ " sc %2, %1 \n"
+ " beqzl %2, 1b \n"
+ " nop \n"
+ " andi %2, %0, 1 \n"
+ " sync \n"
+ " .set reorder"
+ : "=&r" (temp), "=m" (lock->lock), "=&r" (res)
+ : "m" (lock->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_spin_trylock \n"
+ "1: ll %0, %3 \n"
+ " ori %2, %0, 1 \n"
+ " sc %2, %1 \n"
+ " beqz %2, 1b \n"
+ " andi %2, %0, 1 \n"
+ " sync \n"
+ " .set reorder"
+ : "=&r" (temp), "=m" (lock->lock), "=&r" (res)
+ : "m" (lock->lock)
+ : "memory");
+ }
+
+ return res == 0;
+}
+
+/*
+ * 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 {
+ volatile unsigned int lock;
+#ifdef CONFIG_PREEMPT
+ unsigned int break_lock;
+#endif
+} rwlock_t;
+
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
+
+#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
+
+static inline void _raw_read_lock(rwlock_t *rw)
+{
+ unsigned int tmp;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_read_lock \n"
+ "1: ll %1, %2 \n"
+ " bltz %1, 1b \n"
+ " addu %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqzl %1, 1b \n"
+ " nop \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_read_lock \n"
+ "1: ll %1, %2 \n"
+ " bltz %1, 1b \n"
+ " addu %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqz %1, 1b \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ }
+}
+
+/* Note the use of sub, not subu which will make the kernel die with an
+ overflow exception if we ever try to unlock an rwlock that is already
+ unlocked or is being held by a writer. */
+static inline void _raw_read_unlock(rwlock_t *rw)
+{
+ unsigned int tmp;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ "1: ll %1, %2 # _raw_read_unlock \n"
+ " sub %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqzl %1, 1b \n"
+ " sync \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_read_unlock \n"
+ "1: ll %1, %2 \n"
+ " sub %1, 1 \n"
+ " sc %1, %0 \n"
+ " beqz %1, 1b \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ }
+}
+
+static inline void _raw_write_lock(rwlock_t *rw)
+{
+ unsigned int tmp;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_write_lock \n"
+ "1: ll %1, %2 \n"
+ " bnez %1, 1b \n"
+ " lui %1, 0x8000 \n"
+ " sc %1, %0 \n"
+ " beqzl %1, 1b \n"
+ " nop \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_write_lock \n"
+ "1: ll %1, %2 \n"
+ " bnez %1, 1b \n"
+ " lui %1, 0x8000 \n"
+ " sc %1, %0 \n"
+ " beqz %1, 1b \n"
+ " nop \n"
+ " sync \n"
+ " .set reorder \n"
+ : "=m" (rw->lock), "=&r" (tmp)
+ : "m" (rw->lock)
+ : "memory");
+ }
+}
+
+static inline void _raw_write_unlock(rwlock_t *rw)
+{
+ __asm__ __volatile__(
+ " sync # _raw_write_unlock \n"
+ " sw $0, %0 \n"
+ : "=m" (rw->lock)
+ : "m" (rw->lock)
+ : "memory");
+}
+
+#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
+
+static inline int _raw_write_trylock(rwlock_t *rw)
+{
+ unsigned int tmp;
+ int ret;
+
+ if (R10000_LLSC_WAR) {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_write_trylock \n"
+ " li %2, 0 \n"
+ "1: ll %1, %3 \n"
+ " bnez %1, 2f \n"
+ " lui %1, 0x8000 \n"
+ " sc %1, %0 \n"
+ " beqzl %1, 1b \n"
+ " nop \n"
+ " sync \n"
+ " li %2, 1 \n"
+ " .set reorder \n"
+ "2: \n"
+ : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
+ : "m" (rw->lock)
+ : "memory");
+ } else {
+ __asm__ __volatile__(
+ " .set noreorder # _raw_write_trylock \n"
+ " li %2, 0 \n"
+ "1: ll %1, %3 \n"
+ " bnez %1, 2f \n"
+ " lui %1, 0x8000 \n"
+ " sc %1, %0 \n"
+ " beqz %1, 1b \n"
+ " sync \n"
+ " li %2, 1 \n"
+ " .set reorder \n"
+ "2: \n"
+ : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret)
+ : "m" (rw->lock)
+ : "memory");
+ }
+
+ return ret;
+}
+
+#endif /* _ASM_SPINLOCK_H */
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