path: root/include/asm-mips/bitops.h

/*
 * 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, 1999, 2000  Ralf Baechle (ralf@gnu.org)
 * Copyright (c) 1999, 2000  Silicon Graphics, Inc.
 */
#ifndef _ASM_BITOPS_H
#define _ASM_BITOPS_H

#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/bug.h>
#include <asm/byteorder.h>		/* sigh ... */
#include <asm/cpu-features.h>

#if (_MIPS_SZLONG == 32)
#define SZLONG_LOG 5
#define SZLONG_MASK 31UL
#define __LL		"ll	"
#define __SC		"sc	"
#define cpu_to_lelongp(x) cpu_to_le32p((__u32 *) (x))
#elif (_MIPS_SZLONG == 64)
#define SZLONG_LOG 6
#define SZLONG_MASK 63UL
#define __LL		"lld	"
#define __SC		"scd	"
#define cpu_to_lelongp(x) cpu_to_le64p((__u64 *) (x))
#endif

#ifdef __KERNEL__

#include <asm/interrupt.h>
#include <asm/sgidefs.h>
#include <asm/war.h>

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

/*
 * Only disable interrupt for kernel mode stuff to keep usermode stuff
 * that dares to use kernel include files alive.
 */

#define __bi_flags			unsigned long flags
#define __bi_local_irq_save(x)		local_irq_save(x)
#define __bi_local_irq_restore(x)	local_irq_restore(x)
#else
#define __bi_flags
#define __bi_local_irq_save(x)
#define __bi_local_irq_restore(x)
#endif /* __KERNEL__ */

/*
 * 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 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 << (nr & SZLONG_MASK)), "m" (*m));
	} 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, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		*a |= mask;
		__bi_local_irq_restore(flags);
	}
}

/*
 * __set_bit - Set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 *
 * Unlike set_bit(), this function is non-atomic and may be reordered.
 * If it's called on the same region of memory simultaneously, the effect
 * may be that only one operation succeeds.
 */
static inline void __set_bit(unsigned long nr, volatile unsigned long * addr)
{
	unsigned long * m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);

	*m |= 1UL << (nr & SZLONG_MASK);
}

/*
 * 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 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 << (nr & SZLONG_MASK))), "m" (*m));
	} 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, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (~(1UL << (nr & SZLONG_MASK))), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		*a &= ~mask;
		__bi_local_irq_restore(flags);
	}
}