1#ifdef __KERNEL__
2#ifndef __ASM_HARDIRQ_H
3#define __ASM_HARDIRQ_H
4
5/*
6 * Use a brlock for the global irq lock, based on sparc64.
7 * Anton Blanchard <anton@au1.ibm.com>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15#include <linux/config.h>
16#include <linux/brlock.h>
17#include <linux/spinlock.h>
18
19
20typedef struct {
21	unsigned long __softirq_pending;
22#ifndef CONFIG_SMP
23	unsigned int __local_irq_count;
24#else
25	unsigned int __unused_on_SMP;		/* We use brlocks on SMP */
26#endif
27	unsigned int __local_bh_count;
28	unsigned int __syscall_count;
29	unsigned long __unused;
30	struct task_struct * __ksoftirqd_task;
31} ____cacheline_aligned irq_cpustat_t;
32
33#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
34/* Note that local_irq_count() is replaced by ppc64 specific version for SMP */
35
36#ifndef CONFIG_SMP
37#define irq_enter(cpu)		(local_irq_count(cpu)++)
38#define irq_exit(cpu)		(local_irq_count(cpu)--)
39#else
40#undef local_irq_count
41#define local_irq_count(cpu)	(__brlock_array[cpu][BR_GLOBALIRQ_LOCK])
42#define irq_enter(cpu)		br_read_lock(BR_GLOBALIRQ_LOCK)
43#define irq_exit(cpu)		br_read_unlock(BR_GLOBALIRQ_LOCK)
44#endif
45
46/*
47 * Are we in an interrupt context? Either doing bottom half
48 * or hardware interrupt processing?
49 */
50#define in_interrupt() ({ int __cpu = smp_processor_id(); \
51	(local_irq_count(__cpu) + local_bh_count(__cpu) != 0); })
52
53/* This tests only the local processors hw IRQ context disposition.  */
54#define in_irq() (local_irq_count(smp_processor_id()) != 0)
55
56#ifndef CONFIG_SMP
57
58#define hardirq_trylock(cpu)	(local_irq_count(cpu) == 0)
59#define hardirq_endlock(cpu)	do { } while (0)
60
61#define synchronize_irq()	barrier()
62
63#else /* CONFIG_SMP */
64
65static __inline__ int irqs_running(void)
66{
67	int i;
68
69	for (i = 0; i < smp_num_cpus; i++)
70		if (local_irq_count(cpu_logical_map(i)))
71			return 1;
72	return 0;
73}
74
75extern unsigned char global_irq_holder;
76
77static inline void release_irqlock(int cpu)
78{
79	/* if we didn't own the irq lock, just ignore... */
80	if(global_irq_holder == (unsigned char) cpu) {
81		global_irq_holder = NO_PROC_ID;
82		br_write_unlock(BR_GLOBALIRQ_LOCK);
83	}
84}
85
86static inline int hardirq_trylock(int cpu)
87{
88	spinlock_t *lock = &__br_write_locks[BR_GLOBALIRQ_LOCK].lock;
89
90	return (!local_irq_count(cpu) && !spin_is_locked(lock));
91}
92
93#define hardirq_endlock(cpu)    do { (void)(cpu); } while (0)
94
95extern void synchronize_irq(void);
96
97#endif /* CONFIG_SMP */
98
99#endif /* __KERNEL__ */
100#endif /* __ASM_HARDIRQ_H */
101