[linux-block.git] / arch / s390 / lib / spinlock.c

/*
 *  arch/s390/lib/spinlock.c
 *    Out of line spinlock code.
 *
 *    Copyright (C) IBM Corp. 2004, 2006
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <asm/io.h>

int spin_retry = 1000;

/**
 * spin_retry= parameter
 */
static int __init spin_retry_setup(char *str)
{
	spin_retry = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("spin_retry=", spin_retry_setup);

static inline void _raw_yield(void)
{
	if (MACHINE_HAS_DIAG44)
		asm volatile("diag 0,0,0x44");
}

static inline void _raw_yield_cpu(int cpu)
{
	if (MACHINE_HAS_DIAG9C)
		asm volatile("diag %0,0,0x9c"
			     : : "d" (__cpu_logical_map[cpu]));
	else
		_raw_yield();
}

void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
{
	int count = spin_retry;
	unsigned int cpu = ~smp_processor_id();

	while (1) {
		if (count-- <= 0) {
			unsigned int owner = lp->owner_cpu;
			if (owner != 0)
				_raw_yield_cpu(~owner);
			count = spin_retry;
		}
		if (__raw_spin_is_locked(lp))
			continue;
		if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
			lp->owner_pc = pc;
			return;
		}
	}
}
EXPORT_SYMBOL(_raw_spin_lock_wait);

int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
{
	unsigned int cpu = ~smp_processor_id();
	int count;

	for (count = spin_retry; count > 0; count--) {
		if (__raw_spin_is_locked(lp))
			continue;
		if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
			lp->owner_pc = pc;
			return 1;
		}
	}
	return 0;
}
EXPORT_SYMBOL(_raw_spin_trylock_retry);

void _raw_spin_relax(raw_spinlock_t *lock)
{
	unsigned int cpu = lock->owner_cpu;
	if (cpu != 0)
		_raw_yield_cpu(~cpu);
}
EXPORT_SYMBOL(_raw_spin_relax);

void _raw_read_lock_wait(raw_rwlock_t *rw)
{
	unsigned int old;
	int count = spin_retry;

	while (1) {
		if (count-- <= 0) {
			_raw_yield();
			count = spin_retry;
		}
		if (!__raw_read_can_lock(rw))
			continue;
		old = rw->lock & 0x7fffffffU;
		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
			return;
	}
}
EXPORT_SYMBOL(_raw_read_lock_wait);

int _raw_read_trylock_retry(raw_rwlock_t *rw)
{
	unsigned int old;
	int count = spin_retry;

	while (count-- > 0) {
		if (!__raw_read_can_lock(rw))
			continue;
		old = rw->lock & 0x7fffffffU;
		if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
			return 1;
	}
	return 0;
}
EXPORT_SYMBOL(_raw_read_trylock_retry);

void _raw_write_lock_wait(raw_rwlock_t *rw)
{
	int count = spin_retry;

	while (1) {
		if (count-- <= 0) {
			_raw_yield();
			count = spin_retry;
		}
		if (!__raw_write_can_lock(rw))
			continue;
		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
			return;
	}
}
EXPORT_SYMBOL(_raw_write_lock_wait);

int _raw_write_trylock_retry(raw_rwlock_t *rw)
{
	int count = spin_retry;

	while (count-- > 0) {
		if (!__raw_write_can_lock(rw))
			continue;
		if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
			return 1;
	}
	return 0;
}
EXPORT_SYMBOL(_raw_write_trylock_retry);
Commit	Line	Data
951f22d5 MS	1	/*
	2	* arch/s390/lib/spinlock.c
	3	* Out of line spinlock code.
	4	*
96567161	5	* Copyright (C) IBM Corp. 2004, 2006
951f22d5 MS	6	* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
	7	*/
	8
	9	#include <linux/types.h>
	10	#include <linux/module.h>
	11	#include <linux/spinlock.h>
	12	#include <linux/init.h>
	13	#include <asm/io.h>
	14
951f22d5 MS	15	int spin_retry = 1000;
	16
	17	/**
	18	* spin_retry= parameter
	19	*/
	20	static int __init spin_retry_setup(char *str)
	21	{
	22	spin_retry = simple_strtoul(str, &str, 0);
	23	return 1;
	24	}
	25	__setup("spin_retry=", spin_retry_setup);
	26
3c1fcfe2	27	static inline void _raw_yield(void)
951f22d5	28	{
951f22d5	29	if (MACHINE_HAS_DIAG44)
951f22d5 MS	30	asm volatile("diag 0,0,0x44");
	31	}
	32
3c1fcfe2 MS	33	static inline void _raw_yield_cpu(int cpu)
	34	{
	35	if (MACHINE_HAS_DIAG9C)
	36	asm volatile("diag %0,0,0x9c"
	37	: : "d" (__cpu_logical_map[cpu]));
	38	else
	39	_raw_yield();
	40	}
	41
	42	void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
951f22d5 MS	43	{
951f22d5 MS	44	int count = spin_retry;
3c1fcfe2	45	unsigned int cpu = ~smp_processor_id();
951f22d5 MS	46
	47	while (1) {
	48	if (count-- <= 0) {
3c1fcfe2 MS	49	unsigned int owner = lp->owner_cpu;
	50	if (owner != 0)
	51	_raw_yield_cpu(~owner);
951f22d5 MS	52	count = spin_retry;
951f22d5 MS	53	}
96567161 CE	54	if (__raw_spin_is_locked(lp))
96567161 CE	55	continue;
3c1fcfe2 MS	56	if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
3c1fcfe2 MS	57	lp->owner_pc = pc;
951f22d5	58	return;
3c1fcfe2	59	}
951f22d5 MS	60	}
	61	}
	62	EXPORT_SYMBOL(_raw_spin_lock_wait);
	63
3c1fcfe2	64	int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
951f22d5	65	{
3c1fcfe2 MS	66	unsigned int cpu = ~smp_processor_id();
3c1fcfe2 MS	67	int count;
951f22d5	68
3c1fcfe2	69	for (count = spin_retry; count > 0; count--) {
96567161 CE	70	if (__raw_spin_is_locked(lp))
96567161 CE	71	continue;
3c1fcfe2 MS	72	if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) {
3c1fcfe2 MS	73	lp->owner_pc = pc;
951f22d5	74	return 1;
3c1fcfe2	75	}
951f22d5 MS	76	}
	77	return 0;
	78	}
	79	EXPORT_SYMBOL(_raw_spin_trylock_retry);
	80
3c1fcfe2 MS	81	void _raw_spin_relax(raw_spinlock_t *lock)
	82	{
	83	unsigned int cpu = lock->owner_cpu;
	84	if (cpu != 0)
	85	_raw_yield_cpu(~cpu);
	86	}
	87	EXPORT_SYMBOL(_raw_spin_relax);
	88
	89	void _raw_read_lock_wait(raw_rwlock_t *rw)
951f22d5 MS	90	{
	91	unsigned int old;
	92	int count = spin_retry;
	93
	94	while (1) {
	95	if (count-- <= 0) {
3c1fcfe2	96	_raw_yield();
951f22d5 MS	97	count = spin_retry;
951f22d5 MS	98	}
96567161 CE	99	if (!__raw_read_can_lock(rw))
96567161 CE	100	continue;
951f22d5 MS	101	old = rw->lock & 0x7fffffffU;
	102	if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
	103	return;
	104	}
	105	}
	106	EXPORT_SYMBOL(_raw_read_lock_wait);
	107
3c1fcfe2	108	int _raw_read_trylock_retry(raw_rwlock_t *rw)
951f22d5 MS	109	{
	110	unsigned int old;
	111	int count = spin_retry;
	112
	113	while (count-- > 0) {
96567161 CE	114	if (!__raw_read_can_lock(rw))
96567161 CE	115	continue;
951f22d5 MS	116	old = rw->lock & 0x7fffffffU;
	117	if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
	118	return 1;
	119	}
	120	return 0;
	121	}
	122	EXPORT_SYMBOL(_raw_read_trylock_retry);
	123
3c1fcfe2	124	void _raw_write_lock_wait(raw_rwlock_t *rw)
951f22d5 MS	125	{
	126	int count = spin_retry;
	127
	128	while (1) {
	129	if (count-- <= 0) {
3c1fcfe2	130	_raw_yield();
951f22d5 MS	131	count = spin_retry;
951f22d5 MS	132	}
96567161 CE	133	if (!__raw_write_can_lock(rw))
96567161 CE	134	continue;
951f22d5 MS	135	if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
	136	return;
	137	}
	138	}
	139	EXPORT_SYMBOL(_raw_write_lock_wait);
	140
3c1fcfe2	141	int _raw_write_trylock_retry(raw_rwlock_t *rw)
951f22d5 MS	142	{
	143	int count = spin_retry;
	144
	145	while (count-- > 0) {
96567161 CE	146	if (!__raw_write_can_lock(rw))
96567161 CE	147	continue;
951f22d5 MS	148	if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
	149	return 1;
	150	}
	151	return 0;
	152	}
	153	EXPORT_SYMBOL(_raw_write_trylock_retry);