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Date: Tue, 26 Oct 2010 03:55:47 +0100
From: David Howells <dhowells@...hat.com>
To: linux-am33-list@...hat.com
Cc: linux-kernel@...r.kernel.org, Mark Salter <msalter@...hat.com>
Subject: [PATCH 31/43] MN10300: Implement atomic ops using atomic ops unit
From: Mark Salter <msalter@...hat.com>
Implement atomic ops using the atomic ops unit available in the AM34 CPU. This
allows the equivalent of the LL/SC instructions to be found on other CPUs.
Signed-off-by: Mark Salter <msalter@...hat.com>
Signed-off-by: David Howells <dhowells@...hat.com>
---
arch/mn10300/include/asm/atomic.h | 350 +++++++++++++++++++++++++++++++++++++
arch/mn10300/include/asm/system.h | 48 -----
2 files changed, 351 insertions(+), 47 deletions(-)
diff --git a/arch/mn10300/include/asm/atomic.h b/arch/mn10300/include/asm/atomic.h
index f0cc1f8..92d2f92 100644
--- a/arch/mn10300/include/asm/atomic.h
+++ b/arch/mn10300/include/asm/atomic.h
@@ -1 +1,351 @@
+/* MN10300 Atomic counter operations
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@...hat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef _ASM_ATOMIC_H
+#define _ASM_ATOMIC_H
+
+#include <asm/irqflags.h>
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT
+static inline
+unsigned long __xchg(volatile unsigned long *m, unsigned long val)
+{
+ unsigned long status;
+ unsigned long oldval;
+
+ asm volatile(
+ "1: mov %4,(_AAR,%3) \n"
+ " mov (_ADR,%3),%1 \n"
+ " mov %5,(_ADR,%3) \n"
+ " mov (_ADR,%3),%0 \n" /* flush */
+ " mov (_ASR,%3),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=&r"(oldval), "=m"(*m)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(m), "r"(val)
+ : "memory", "cc");
+
+ return oldval;
+}
+
+static inline unsigned long __cmpxchg(volatile unsigned long *m,
+ unsigned long old, unsigned long new)
+{
+ unsigned long status;
+ unsigned long oldval;
+
+ asm volatile(
+ "1: mov %4,(_AAR,%3) \n"
+ " mov (_ADR,%3),%1 \n"
+ " cmp %5,%1 \n"
+ " bne 2f \n"
+ " mov %6,(_ADR,%3) \n"
+ "2: mov (_ADR,%3),%0 \n" /* flush */
+ " mov (_ASR,%3),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=&r"(oldval), "=m"(*m)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(m),
+ "r"(old), "r"(new)
+ : "memory", "cc");
+
+ return oldval;
+}
+#else /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */
+#error "No SMP atomic operation support!"
+#endif /* CONFIG_MN10300_HAS_ATOMIC_OPS_UNIT */
+
+#else /* CONFIG_SMP */
+
+/*
+ * Emulate xchg for non-SMP MN10300
+ */
+struct __xchg_dummy { unsigned long a[100]; };
+#define __xg(x) ((struct __xchg_dummy *)(x))
+
+static inline
+unsigned long __xchg(volatile unsigned long *m, unsigned long val)
+{
+ unsigned long oldval;
+ unsigned long flags;
+
+ flags = arch_local_cli_save();
+ oldval = *m;
+ *m = val;
+ arch_local_irq_restore(flags);
+ return oldval;
+}
+
+/*
+ * Emulate cmpxchg for non-SMP MN10300
+ */
+static inline unsigned long __cmpxchg(volatile unsigned long *m,
+ unsigned long old, unsigned long new)
+{
+ unsigned long oldval;
+ unsigned long flags;
+
+ flags = arch_local_cli_save();
+ oldval = *m;
+ if (oldval == old)
+ *m = new;
+ arch_local_irq_restore(flags);
+ return oldval;
+}
+
+#endif /* CONFIG_SMP */
+
+#define xchg(ptr, v) \
+ ((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
+ (unsigned long)(v)))
+
+#define cmpxchg(ptr, o, n) \
+ ((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
+ (unsigned long)(o), \
+ (unsigned long)(n)))
+
+#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
+#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
+
+#endif /* !__ASSEMBLY__ */
+
+#ifndef CONFIG_SMP
#include <asm-generic/atomic.h>
+#else
+
+/*
+ * Atomic operations that C can't guarantee us. Useful for
+ * resource counting etc..
+ */
+
+#define ATOMIC_INIT(i) { (i) }
+
+#ifdef __KERNEL__
+
+/**
+ * atomic_read - read atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically reads the value of @v. Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+#define atomic_read(v) ((v)->counter)
+
+/**
+ * atomic_set - set atomic variable
+ * @v: pointer of type atomic_t
+ * @i: required value
+ *
+ * Atomically sets the value of @v to @i. Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+#define atomic_set(v, i) (((v)->counter) = (i))
+
+/**
+ * atomic_add_return - add integer to atomic variable
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ *
+ * Atomically adds @i to @v and returns the result
+ * Note that the guaranteed useful range of an atomic_t is only 24 bits.
+ */
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+ int retval;
+#ifdef CONFIG_SMP
+ int status;
+
+ asm volatile(
+ "1: mov %4,(_AAR,%3) \n"
+ " mov (_ADR,%3),%1 \n"
+ " add %5,%1 \n"
+ " mov %1,(_ADR,%3) \n"
+ " mov (_ADR,%3),%0 \n" /* flush */
+ " mov (_ASR,%3),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=&r"(retval), "=m"(v->counter)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i)
+ : "memory", "cc");
+
+#else
+ unsigned long flags;
+
+ flags = arch_local_cli_save();
+ retval = v->counter;
+ retval += i;
+ v->counter = retval;
+ arch_local_irq_restore(flags);
+#endif
+ return retval;
+}
+
+/**
+ * atomic_sub_return - subtract integer from atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ *
+ * Atomically subtracts @i from @v and returns the result
+ * Note that the guaranteed useful range of an atomic_t is only 24 bits.
+ */
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+ int retval;
+#ifdef CONFIG_SMP
+ int status;
+
+ asm volatile(
+ "1: mov %4,(_AAR,%3) \n"
+ " mov (_ADR,%3),%1 \n"
+ " sub %5,%1 \n"
+ " mov %1,(_ADR,%3) \n"
+ " mov (_ADR,%3),%0 \n" /* flush */
+ " mov (_ASR,%3),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=&r"(retval), "=m"(v->counter)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i)
+ : "memory", "cc");
+
+#else
+ unsigned long flags;
+ flags = arch_local_cli_save();
+ retval = v->counter;
+ retval -= i;
+ v->counter = retval;
+ arch_local_irq_restore(flags);
+#endif
+ return retval;
+}
+
+static inline int atomic_add_negative(int i, atomic_t *v)
+{
+ return atomic_add_return(i, v) < 0;
+}
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+ atomic_add_return(i, v);
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+ atomic_sub_return(i, v);
+}
+
+static inline void atomic_inc(atomic_t *v)
+{
+ atomic_add_return(1, v);
+}
+
+static inline void atomic_dec(atomic_t *v)
+{
+ atomic_sub_return(1, v);
+}
+
+#define atomic_dec_return(v) atomic_sub_return(1, (v))
+#define atomic_inc_return(v) atomic_add_return(1, (v))
+
+#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
+#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
+#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
+
+#define atomic_add_unless(v, a, u) \
+({ \
+ int c, old; \
+ c = atomic_read(v); \
+ while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
+ c = old; \
+ c != (u); \
+})
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
+/**
+ * atomic_clear_mask - Atomically clear bits in memory
+ * @mask: Mask of the bits to be cleared
+ * @v: pointer to word in memory
+ *
+ * Atomically clears the bits set in mask from the memory word specified.
+ */
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+#ifdef CONFIG_SMP
+ int status;
+
+ asm volatile(
+ "1: mov %3,(_AAR,%2) \n"
+ " mov (_ADR,%2),%0 \n"
+ " and %4,%0 \n"
+ " mov %0,(_ADR,%2) \n"
+ " mov (_ADR,%2),%0 \n" /* flush */
+ " mov (_ASR,%2),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=m"(*addr)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(addr), "r"(~mask)
+ : "memory", "cc");
+#else
+ unsigned long flags;
+
+ mask = ~mask;
+ flags = arch_local_cli_save();
+ *addr &= mask;
+ arch_local_irq_restore(flags);
+#endif
+}
+
+/**
+ * atomic_set_mask - Atomically set bits in memory
+ * @mask: Mask of the bits to be set
+ * @v: pointer to word in memory
+ *
+ * Atomically sets the bits set in mask from the memory word specified.
+ */
+static inline void atomic_set_mask(unsigned long mask, unsigned long *addr)
+{
+#ifdef CONFIG_SMP
+ int status;
+
+ asm volatile(
+ "1: mov %3,(_AAR,%2) \n"
+ " mov (_ADR,%2),%0 \n"
+ " or %4,%0 \n"
+ " mov %0,(_ADR,%2) \n"
+ " mov (_ADR,%2),%0 \n" /* flush */
+ " mov (_ASR,%2),%0 \n"
+ " or %0,%0 \n"
+ " bne 1b \n"
+ : "=&r"(status), "=m"(*addr)
+ : "a"(ATOMIC_OPS_BASE_ADDR), "r"(addr), "r"(mask)
+ : "memory", "cc");
+#else
+ unsigned long flags;
+
+ flags = arch_local_cli_save();
+ *addr |= mask;
+ arch_local_irq_restore(flags);
+#endif
+}
+
+/* Atomic operations are already serializing on MN10300??? */
+#define smp_mb__before_atomic_dec() barrier()
+#define smp_mb__after_atomic_dec() barrier()
+#define smp_mb__before_atomic_inc() barrier()
+#define smp_mb__after_atomic_inc() barrier()
+
+#include <asm-generic/atomic-long.h>
+
+#endif /* __KERNEL__ */
+#endif /* CONFIG_SMP */
+#endif /* _ASM_ATOMIC_H */
diff --git a/arch/mn10300/include/asm/system.h b/arch/mn10300/include/asm/system.h
index 3c272a1..7de90bc 100644
--- a/arch/mn10300/include/asm/system.h
+++ b/arch/mn10300/include/asm/system.h
@@ -18,6 +18,7 @@
#include <linux/kernel.h>
#include <linux/irqflags.h>
+#include <asm/atomic.h>
#if !defined(CONFIG_LAZY_SAVE_FPU)
struct fpu_state_struct;
@@ -96,52 +97,5 @@ do { \
#define read_barrier_depends() do {} while (0)
#define smp_read_barrier_depends() do {} while (0)
-/*****************************************************************************/
-/*
- * MN10300 doesn't actually have an exchange instruction
- */
-#ifndef __ASSEMBLY__
-
-struct __xchg_dummy { unsigned long a[100]; };
-#define __xg(x) ((struct __xchg_dummy *)(x))
-
-static inline
-unsigned long __xchg(volatile unsigned long *m, unsigned long val)
-{
- unsigned long retval;
- unsigned long flags;
-
- local_irq_save(flags);
- retval = *m;
- *m = val;
- local_irq_restore(flags);
- return retval;
-}
-
-#define xchg(ptr, v) \
- ((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
- (unsigned long)(v)))
-
-static inline unsigned long __cmpxchg(volatile unsigned long *m,
- unsigned long old, unsigned long new)
-{
- unsigned long retval;
- unsigned long flags;
-
- local_irq_save(flags);
- retval = *m;
- if (retval == old)
- *m = new;
- local_irq_restore(flags);
- return retval;
-}
-
-#define cmpxchg(ptr, o, n) \
- ((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
- (unsigned long)(o), \
- (unsigned long)(n)))
-
-#endif /* !__ASSEMBLY__ */
-
#endif /* __KERNEL__ */
#endif /* _ASM_SYSTEM_H */
--
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