[deliverable/linux.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)
{
	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)
			return;
	}
}
EXPORT_SYMBOL(_raw_spin_lock_wait);

int _raw_spin_trylock_retry(raw_spinlock_t *lp)
{
	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)
			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
3b4beb31	42	void _raw_spin_lock_wait(raw_spinlock_t *lp)
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;
3b4beb31	56	if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
951f22d5 MS	57	return;
	58	}
	59	}
	60	EXPORT_SYMBOL(_raw_spin_lock_wait);
	61
3b4beb31	62	int _raw_spin_trylock_retry(raw_spinlock_t *lp)
951f22d5	63	{
3c1fcfe2 MS	64	unsigned int cpu = ~smp_processor_id();
3c1fcfe2 MS	65	int count;
951f22d5	66
3c1fcfe2	67	for (count = spin_retry; count > 0; count--) {
96567161 CE	68	if (__raw_spin_is_locked(lp))
96567161 CE	69	continue;
3b4beb31	70	if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
951f22d5 MS	71	return 1;
	72	}
	73	return 0;
	74	}
	75	EXPORT_SYMBOL(_raw_spin_trylock_retry);
	76
3c1fcfe2 MS	77	void _raw_spin_relax(raw_spinlock_t *lock)
	78	{
	79	unsigned int cpu = lock->owner_cpu;
	80	if (cpu != 0)
	81	_raw_yield_cpu(~cpu);
	82	}
	83	EXPORT_SYMBOL(_raw_spin_relax);
	84
	85	void _raw_read_lock_wait(raw_rwlock_t *rw)
951f22d5 MS	86	{
	87	unsigned int old;
	88	int count = spin_retry;
	89
	90	while (1) {
	91	if (count-- <= 0) {
3c1fcfe2	92	_raw_yield();
951f22d5 MS	93	count = spin_retry;
951f22d5 MS	94	}
96567161 CE	95	if (!__raw_read_can_lock(rw))
96567161 CE	96	continue;
951f22d5 MS	97	old = rw->lock & 0x7fffffffU;
	98	if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
	99	return;
	100	}
	101	}
	102	EXPORT_SYMBOL(_raw_read_lock_wait);
	103
3c1fcfe2	104	int _raw_read_trylock_retry(raw_rwlock_t *rw)
951f22d5 MS	105	{
	106	unsigned int old;
	107	int count = spin_retry;
	108
	109	while (count-- > 0) {
96567161 CE	110	if (!__raw_read_can_lock(rw))
96567161 CE	111	continue;
951f22d5 MS	112	old = rw->lock & 0x7fffffffU;
	113	if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
	114	return 1;
	115	}
	116	return 0;
	117	}
	118	EXPORT_SYMBOL(_raw_read_trylock_retry);
	119
3c1fcfe2	120	void _raw_write_lock_wait(raw_rwlock_t *rw)
951f22d5 MS	121	{
	122	int count = spin_retry;
	123
	124	while (1) {
	125	if (count-- <= 0) {
3c1fcfe2	126	_raw_yield();
951f22d5 MS	127	count = spin_retry;
951f22d5 MS	128	}
96567161 CE	129	if (!__raw_write_can_lock(rw))
96567161 CE	130	continue;
951f22d5 MS	131	if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
	132	return;
	133	}
	134	}
	135	EXPORT_SYMBOL(_raw_write_lock_wait);
	136
3c1fcfe2	137	int _raw_write_trylock_retry(raw_rwlock_t *rw)
951f22d5 MS	138	{
	139	int count = spin_retry;
	140
	141	while (count-- > 0) {
96567161 CE	142	if (!__raw_write_can_lock(rw))
96567161 CE	143	continue;
951f22d5 MS	144	if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
	145	return 1;
	146	}
	147	return 0;
	148	}
	149	EXPORT_SYMBOL(_raw_write_trylock_retry);