bitops.h

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/*
 * 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) 1994 - 1997, 99, 2000, 06, 07  Ralf Baechle ([e-mail])
 * Copyright (c) 1999, 2000  Silicon Graphics, Inc.
 */
#ifndef _ASM_BITOPS_H
#define _ASM_BITOPS_H

#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif

#include <linux/compiler.h>
#include <linux/irqflags.h>
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/bug.h>
#include <asm/byteorder.h>		/* sigh ... */
#include <asm/cpu-features.h>
#include <asm/sgidefs.h>
#include <asm/war.h>

#if _MIPS_SZLONG == 32
#define SZLONG_LOG 5
#define SZLONG_MASK 31UL
#define __LL		"ll	"
#define __SC		"sc	"
#define __INS		"ins    "
#define __EXT		"ext    "
#elif _MIPS_SZLONG == 64
#define SZLONG_LOG 6
#define SZLONG_MASK 63UL
#define __LL		"lld	"
#define __SC		"scd	"
#define __INS		"dins    "
#define __EXT		"dext    "
#endif

/*
 * clear_bit() doesn't provide any barrier for the compiler.
 */
#define smp_mb__before_clear_bit()	smp_llsc_mb()
#define smp_mb__after_clear_bit()	smp_llsc_mb()

/*
 * set_bit - Atomically set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 *
 * This function is atomic and may not be reordered.  See __set_bit()
 * if you do not require the atomic guarantees.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
{
	unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
	unsigned short bit = nr & SZLONG_MASK;
	unsigned long temp;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# set_bit	\n"
		"	or	%0, %2					\n"
		"	" __SC	"%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << bit), "m" (*m));
#ifdef CONFIG_CPU_MIPSR2
	} else if (__builtin_constant_p(bit)) {
		__asm__ __volatile__(
		"1:	" __LL "%0, %1			# set_bit	\n"
		"	" __INS "%0, %4, %2, 1				\n"
		"	" __SC "%0, %1					\n"
		"	beqz	%0, 2f					\n"
		"	.subsection 2					\n"
		"2:	b	1b					\n"
		"	.previous					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (bit), "m" (*m), "r" (~0));
#endif /* CONFIG_CPU_MIPSR2 */
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# set_bit	\n"
		"	or	%0, %2					\n"
		"	" __SC	"%0, %1					\n"
		"	beqz	%0, 2f					\n"
		"	.subsection 2					\n"
		"2:	b	1b					\n"
		"	.previous					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << bit), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		unsigned long flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << bit;
		raw_local_irq_save(flags);
		*a |= mask;
		raw_local_irq_restore(flags);
	}
}

/*
 * clear_bit - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * clear_bit() is atomic and may not be reordered.  However, it does
 * not contain a memory barrier, so if it is used for locking purposes,
 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
 * in order to ensure changes are visible on other processors.
 */
static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
{
	unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
	unsigned short bit = nr & SZLONG_MASK;
	unsigned long temp;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# clear_bit	\n"
		"	and	%0, %2					\n"
		"	" __SC "%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (~(1UL << bit)), "m" (*m));
#ifdef CONFIG_CPU_MIPSR2
	} else if (__builtin_constant_p(bit)) {
		__asm__ __volatile__(
		"1:	" __LL "%0, %1			# clear_bit	\n"
		"	" __INS "%0, $0, %2, 1				\n"
		"	" __SC "%0, %1					\n"
		"	beqz	%0, 2f					\n"
		"	.subsection 2					\n"
		"2:	b	1b					\n"
		"	.previous					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (bit), "m" (*m));
#endif /* CONFIG_CPU_MIPSR2 */
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# clear_bit	\n"
		"	and	%0, %2					\n"
		"	" __SC "%0, %1					\n"
		"	beqz	%0, 2f					\n"
		"	.subsection 2					\n"
		"2:	b	1b					\n"
		"	.previous					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (~(1UL << bit)), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		unsigned long flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << bit;
		raw_local_irq_save(flags);
		*a &= ~mask;
		raw_local_irq_restore(flags);
	}
}

/*
 * clear_bit_unlock - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * clear_bit() is atomic and implies release semantics before the memory
 * operation. It can be used for an unlock.
 */
static inline void clear_bit_unlock(unsigned long nr, volatile unsigned long *addr)
{
	smp_mb__before_clear_bit();
	clear_bit(nr, addr);
}

/*
 * change_bit - Toggle a bit in memory
 * @nr: Bit to change
 * @addr: Address to start counting from
 *
 * change_bit() is atomic and may not be reordered.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
{
	unsigned short bit = nr & SZLONG_MASK;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3				\n"
		"1:	" __LL "%0, %1		# change_bit	\n"
		"	xor	%0, %2				\n"
		"	" __SC	"%0, %1				\n"
		"	beqzl	%0, 1b				\n"
		"	.set	mips0				\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << bit), "m" (*m));
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3				\n"
		"1:	" __LL "%0, %1		# change_bit	\n"
		"	xor	%0, %2				\n"
		"	" __SC	"%0, %1				\n"
		"	beqz	%0, 2f				\n"
		"	.subsection 2				\n"
		"2:	b	1b				\n"
		"	.previous				\n"
		"	.set	mips0				\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << bit), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		unsigned long flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << bit;
		raw_local_irq_save(flags);
		*a ^= mask;
		raw_local_irq_restore(flags);
	}
}

/*
 * test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_set_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	unsigned short bit = nr & SZLONG_MASK;
	unsigned long res;

	smp_llsc_mb();

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1		# test_and_set_bit	\n"
		"	or	%2, %0, %3				\n"
		"	" __SC	"%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	and	%2, %0, %3				\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << bit), "m" (*m)
		: "memory");
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noreorder				\n"
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1		# test_and_set_bit	\n"
		"	or	%2, %0, %3				\n"
		"	" __SC	"%2, %1					\n"
		"	beqz	%2, 2f					\n"
		"	 and	%2, %0, %3				\n"
		"	.subsection 2					\n"
		"2:	b	1b					\n"
		"	 nop						\n"
		"	.previous					\n"
		"	.set	pop					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << bit), "m" (*m)
		: "memory");
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		unsigned long flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << bit;
		raw_local_irq_save(flags);
		res = (mask & *a);
		*a |= mask;
		raw_local_irq_restore(flags);
	}

	smp_llsc_mb();

	return res != 0;
}

/*
 * test_and_set_bit_lock - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is atomic and implies acquire ordering semantics
 * after the memory operation.
 */
static inline int test_and_set_bit_lock(unsigned long nr,
	volatile unsigned long *addr)
{
	unsigned short bit = nr & SZLONG_MASK;
	unsigned long res;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3					\n"