1/*
2 * Copyright 2005-2009 Analog Devices Inc.
3 *
4 * Licensed under the GPL-2 or later
5 */
6
7#include <linux/kernel_stat.h>
8#include <linux/module.h>
9#include <linux/random.h>
10#include <linux/seq_file.h>
11#include <linux/kallsyms.h>
12#include <linux/interrupt.h>
13#include <linux/irq.h>
14#include <linux/seq_file.h>
15#include <asm/irq_handler.h>
16#include <asm/trace.h>
17#include <asm/pda.h>
18
19static atomic_t irq_err_count;
20void ack_bad_irq(unsigned int irq)
21{
22	atomic_inc(&irq_err_count);
23	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
24}
25
26static struct irq_desc bad_irq_desc = {
27	.handle_irq = handle_bad_irq,
28	.lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
29};
30
31#ifdef CONFIG_CPUMASK_OFFSTACK
32/* We are not allocating a variable-sized bad_irq_desc.affinity */
33#error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
34#endif
35
36#ifdef CONFIG_PROC_FS
37int arch_show_interrupts(struct seq_file *p, int prec)
38{
39	int j;
40
41	seq_printf(p, "%*s: ", prec, "NMI");
42	for_each_online_cpu(j)
43		seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
44	seq_printf(p, "  CORE  Non Maskable Interrupt\n");
45	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
46	return 0;
47}
48#endif
49
50#ifdef CONFIG_DEBUG_STACKOVERFLOW
51static void check_stack_overflow(int irq)
52{
53	/* Debugging check for stack overflow: is there less than STACK_WARN free? */
54	long sp = __get_SP() & (THREAD_SIZE - 1);
55
56	if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
57		dump_stack();
58		pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
59			irq, sp - sizeof(struct thread_info));
60	}
61}
62#else
63static inline void check_stack_overflow(int irq) { }
64#endif
65
66#ifndef CONFIG_IPIPE
67static void maybe_lower_to_irq14(void)
68{
69	unsigned short pending, other_ints;
70
71	/*
72	 * If we're the only interrupt running (ignoring IRQ15 which
73	 * is for syscalls), lower our priority to IRQ14 so that
74	 * softirqs run at that level.  If there's another,
75	 * lower-level interrupt, irq_exit will defer softirqs to
76	 * that. If the interrupt pipeline is enabled, we are already
77	 * running at IRQ14 priority, so we don't need this code.
78	 */
79	CSYNC();
80	pending = bfin_read_IPEND() & ~0x8000;
81	other_ints = pending & (pending - 1);
82	if (other_ints == 0)
83		lower_to_irq14();
84}
85#else
86static inline void maybe_lower_to_irq14(void) { }
87#endif
88
89/*
90 * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
91 * come via this function.  Instead, they should provide their
92 * own 'handler'
93 */
94#ifdef CONFIG_DO_IRQ_L1
95__attribute__((l1_text))
96#endif
97asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
98{
99	struct pt_regs *old_regs = set_irq_regs(regs);
100
101	irq_enter();
102
103	check_stack_overflow(irq);
104
105	/*
106	 * Some hardware gives randomly wrong interrupts.  Rather
107	 * than crashing, do something sensible.
108	 */
109	if (irq >= NR_IRQS)
110		handle_bad_irq(irq, &bad_irq_desc);
111	else
112		generic_handle_irq(irq);
113
114	maybe_lower_to_irq14();
115
116	irq_exit();
117
118	set_irq_regs(old_regs);
119}
120
121void __init init_IRQ(void)
122{
123	init_arch_irq();
124
125#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
126	/* Now that evt_ivhw is set up, turn this on */
127	trace_buff_offset = 0;
128	bfin_write_TBUFCTL(BFIN_TRACE_ON);
129	printk(KERN_INFO "Hardware Trace expanded to %ik\n",
130	  1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
131#endif
132}
133