summaryrefslogtreecommitdiffstats
path: root/arch/blackfin/kernel/irqchip.c
blob: 052cde5ed2e403111fd8a1639dd29835177d7496 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/*
 * Copyright 2005-2009 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later
 */

#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <asm/irq_handler.h>
#include <asm/trace.h>
#include <asm/pda.h>

static atomic_t irq_err_count;
void ack_bad_irq(unsigned int irq)
{
	atomic_inc(&irq_err_count);
	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
}

static struct irq_desc bad_irq_desc = {
	.handle_irq = handle_bad_irq,
	.lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
};

#ifdef CONFIG_CPUMASK_OFFSTACK
/* We are not allocating a variable-sized bad_irq_desc.affinity */
#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
#endif

#ifdef CONFIG_PROC_FS
int arch_show_interrupts(struct seq_file *p, int prec)
{
	int j;

	seq_printf(p, "%*s: ", prec, "NMI");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
	seq_printf(p, "  CORE  Non Maskable Interrupt\n");
	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
	return 0;
}
#endif

#ifdef CONFIG_DEBUG_STACKOVERFLOW
static void check_stack_overflow(int irq)
{
	/* Debugging check for stack overflow: is there less than STACK_WARN free? */
	long sp = __get_SP() & (THREAD_SIZE - 1);

	if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
		dump_stack();
		pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
			irq, sp - sizeof(struct thread_info));
	}
}
#else
static inline void check_stack_overflow(int irq) { }
#endif

#ifndef CONFIG_IPIPE
static void maybe_lower_to_irq14(void)
{
	unsigned short pending, other_ints;

	/*
	 * If we're the only interrupt running (ignoring IRQ15 which
	 * is for syscalls), lower our priority to IRQ14 so that
	 * softirqs run at that level.  If there's another,
	 * lower-level interrupt, irq_exit will defer softirqs to
	 * that. If the interrupt pipeline is enabled, we are already
	 * running at IRQ14 priority, so we don't need this code.
	 */
	CSYNC();
	pending = bfin_read_IPEND() & ~0x8000;
	other_ints = pending & (pending - 1);
	if (other_ints == 0)
		lower_to_irq14();
}
#else
static inline void maybe_lower_to_irq14(void) { }
#endif

/*
 * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
 * come via this function.  Instead, they should provide their
 * own 'handler'
 */
#ifdef CONFIG_DO_IRQ_L1
__attribute__((l1_text))
#endif
asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	irq_enter();

	check_stack_overflow(irq);

	/*
	 * Some hardware gives randomly wrong interrupts.  Rather
	 * than crashing, do something sensible.
	 */
	if (irq >= NR_IRQS)
		handle_bad_irq(&bad_irq_desc);
	else
		generic_handle_irq(irq);

	maybe_lower_to_irq14();

	irq_exit();

	set_irq_regs(old_regs);
}

void __init init_IRQ(void)
{
	init_arch_irq();

#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
	/* Now that evt_ivhw is set up, turn this on */
	trace_buff_offset = 0;
	bfin_write_TBUFCTL(BFIN_TRACE_ON);
	printk(KERN_INFO "Hardware Trace expanded to %ik\n",
	  1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
#endif
}