[linux-2.6-block.git] / include / asm-generic / qspinlock_types.h

/*
 * Queued spinlock
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
 *
 * Authors: Waiman Long <waiman.long@hp.com>
 */
#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
#define __ASM_GENERIC_QSPINLOCK_TYPES_H

/*
 * Including atomic.h with PARAVIRT on will cause compilation errors because
 * of recursive header file incluson via paravirt_types.h. So don't include
 * it if PARAVIRT is on.
 */
#ifndef CONFIG_PARAVIRT
#include <linux/types.h>
#include <linux/atomic.h>
#endif

typedef struct qspinlock {
	atomic_t	val;
} arch_spinlock_t;

/*
 * Initializier
 */
#define	__ARCH_SPIN_LOCK_UNLOCKED	{ ATOMIC_INIT(0) }

/*
 * Bitfields in the atomic value:
 *
 * When NR_CPUS < 16K
 *  0- 7: locked byte
 *     8: pending
 *  9-15: not used
 * 16-17: tail index
 * 18-31: tail cpu (+1)
 *
 * When NR_CPUS >= 16K
 *  0- 7: locked byte
 *     8: pending
 *  9-10: tail index
 * 11-31: tail cpu (+1)
 */
#define	_Q_SET_MASK(type)	(((1U << _Q_ ## type ## _BITS) - 1)\
				      << _Q_ ## type ## _OFFSET)
#define _Q_LOCKED_OFFSET	0
#define _Q_LOCKED_BITS		8
#define _Q_LOCKED_MASK		_Q_SET_MASK(LOCKED)

#define _Q_PENDING_OFFSET	(_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
#if CONFIG_NR_CPUS < (1U << 14)
#define _Q_PENDING_BITS		8
#else
#define _Q_PENDING_BITS		1
#endif
#define _Q_PENDING_MASK		_Q_SET_MASK(PENDING)

#define _Q_TAIL_IDX_OFFSET	(_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS	2
#define _Q_TAIL_IDX_MASK	_Q_SET_MASK(TAIL_IDX)

#define _Q_TAIL_CPU_OFFSET	(_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS)
#define _Q_TAIL_CPU_BITS	(32 - _Q_TAIL_CPU_OFFSET)
#define _Q_TAIL_CPU_MASK	_Q_SET_MASK(TAIL_CPU)

#define _Q_TAIL_OFFSET		_Q_TAIL_IDX_OFFSET
#define _Q_TAIL_MASK		(_Q_TAIL_IDX_MASK | _Q_TAIL_CPU_MASK)

#define _Q_LOCKED_VAL		(1U << _Q_LOCKED_OFFSET)
#define _Q_PENDING_VAL		(1U << _Q_PENDING_OFFSET)

#endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */
Commit	Line	Data
a33fda35 WL	1	/*
	2	* Queued spinlock
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
	15	*
	16	* Authors: Waiman Long <waiman.long@hp.com>
	17	*/
	18	#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
	19	#define __ASM_GENERIC_QSPINLOCK_TYPES_H
	20
	21	/*
	22	* Including atomic.h with PARAVIRT on will cause compilation errors because
	23	* of recursive header file incluson via paravirt_types.h. So don't include
	24	* it if PARAVIRT is on.
	25	*/
	26	#ifndef CONFIG_PARAVIRT
	27	#include <linux/types.h>
	28	#include <linux/atomic.h>
	29	#endif
	30
	31	typedef struct qspinlock {
	32	atomic_t val;
	33	} arch_spinlock_t;
	34
b82e5302 DS	35	/*
	36	* Initializier
	37	*/
	38	#define __ARCH_SPIN_LOCK_UNLOCKED { ATOMIC_INIT(0) }
	39
a33fda35 WL	40	/*
	41	* Bitfields in the atomic value:
	42	*
69f9cae9 PZI	43	* When NR_CPUS < 16K
	44	* 0- 7: locked byte
	45	* 8: pending
	46	* 9-15: not used
	47	* 16-17: tail index
	48	* 18-31: tail cpu (+1)
	49	*
	50	* When NR_CPUS >= 16K
a33fda35	51	* 0- 7: locked byte
c1fb159d PZI	52	* 8: pending
	53	* 9-10: tail index
	54	* 11-31: tail cpu (+1)
a33fda35 WL	55	*/
	56	#define _Q_SET_MASK(type) (((1U << _Q_ ## type ## _BITS) - 1)\
	57	<< _Q_ ## type ## _OFFSET)
	58	#define _Q_LOCKED_OFFSET 0
	59	#define _Q_LOCKED_BITS 8
	60	#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
	61
c1fb159d	62	#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
69f9cae9 PZI	63	#if CONFIG_NR_CPUS < (1U << 14)
	64	#define _Q_PENDING_BITS 8
	65	#else
c1fb159d	66	#define _Q_PENDING_BITS 1
69f9cae9	67	#endif
c1fb159d PZI	68	#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
	69
	70	#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
a33fda35 WL	71	#define _Q_TAIL_IDX_BITS 2
	72	#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
	73
	74	#define _Q_TAIL_CPU_OFFSET (_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS)
	75	#define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
	76	#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
	77
69f9cae9	78	#define _Q_TAIL_OFFSET _Q_TAIL_IDX_OFFSET
6403bd7d WL	79	#define _Q_TAIL_MASK (_Q_TAIL_IDX_MASK \| _Q_TAIL_CPU_MASK)
6403bd7d WL	80
a33fda35	81	#define _Q_LOCKED_VAL (1U << _Q_LOCKED_OFFSET)
c1fb159d	82	#define _Q_PENDING_VAL (1U << _Q_PENDING_OFFSET)
a33fda35 WL	83
a33fda35 WL	84	#endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */