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 <asm/irq_handler.h>
15 #include <asm/trace.h>
16 #include <asm/pda.h>
17
18 static atomic_t irq_err_count;
ack_bad_irq(unsigned int irq)19 void ack_bad_irq(unsigned int irq)
20 {
21 atomic_inc(&irq_err_count);
22 printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
23 }
24
25 static struct irq_desc bad_irq_desc = {
26 .handle_irq = handle_bad_irq,
27 .lock = __RAW_SPIN_LOCK_UNLOCKED(bad_irq_desc.lock),
28 };
29
30 #ifdef CONFIG_CPUMASK_OFFSTACK
31 /* We are not allocating a variable-sized bad_irq_desc.affinity */
32 #error "Blackfin architecture does not support CONFIG_CPUMASK_OFFSTACK."
33 #endif
34
35 #ifdef CONFIG_PROC_FS
show_interrupts(struct seq_file * p,void * v)36 int show_interrupts(struct seq_file *p, void *v)
37 {
38 int i = *(loff_t *) v, j;
39 struct irqaction *action;
40 unsigned long flags;
41
42 if (i < NR_IRQS) {
43 struct irq_desc *desc = irq_to_desc(i);
44
45 raw_spin_lock_irqsave(&desc->lock, flags);
46 action = desc->action;
47 if (!action)
48 goto skip;
49 seq_printf(p, "%3d: ", i);
50 for_each_online_cpu(j)
51 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
52 seq_printf(p, " %8s", irq_desc_get_chip(desc)->name);
53 seq_printf(p, " %s", action->name);
54 for (action = action->next; action; action = action->next)
55 seq_printf(p, " %s", action->name);
56
57 seq_putc(p, '\n');
58 skip:
59 raw_spin_unlock_irqrestore(&desc->lock, flags);
60 } else if (i == NR_IRQS) {
61 seq_printf(p, "NMI: ");
62 for_each_online_cpu(j)
63 seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
64 seq_printf(p, " CORE Non Maskable Interrupt\n");
65 seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
66 }
67 return 0;
68 }
69 #endif
70
71 #ifdef CONFIG_DEBUG_STACKOVERFLOW
check_stack_overflow(int irq)72 static void check_stack_overflow(int irq)
73 {
74 /* Debugging check for stack overflow: is there less than STACK_WARN free? */
75 long sp = __get_SP() & (THREAD_SIZE - 1);
76
77 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
78 dump_stack();
79 pr_emerg("irq%i: possible stack overflow only %ld bytes free\n",
80 irq, sp - sizeof(struct thread_info));
81 }
82 }
83 #else
check_stack_overflow(int irq)84 static inline void check_stack_overflow(int irq) { }
85 #endif
86
87 #ifndef CONFIG_IPIPE
maybe_lower_to_irq14(void)88 static void maybe_lower_to_irq14(void)
89 {
90 unsigned short pending, other_ints;
91
92 /*
93 * If we're the only interrupt running (ignoring IRQ15 which
94 * is for syscalls), lower our priority to IRQ14 so that
95 * softirqs run at that level. If there's another,
96 * lower-level interrupt, irq_exit will defer softirqs to
97 * that. If the interrupt pipeline is enabled, we are already
98 * running at IRQ14 priority, so we don't need this code.
99 */
100 CSYNC();
101 pending = bfin_read_IPEND() & ~0x8000;
102 other_ints = pending & (pending - 1);
103 if (other_ints == 0)
104 lower_to_irq14();
105 }
106 #else
maybe_lower_to_irq14(void)107 static inline void maybe_lower_to_irq14(void) { }
108 #endif
109
110 /*
111 * do_IRQ handles all hardware IRQs. Decoded IRQs should not
112 * come via this function. Instead, they should provide their
113 * own 'handler'
114 */
115 #ifdef CONFIG_DO_IRQ_L1
116 __attribute__((l1_text))
117 #endif
asm_do_IRQ(unsigned int irq,struct pt_regs * regs)118 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
119 {
120 struct pt_regs *old_regs = set_irq_regs(regs);
121
122 irq_enter();
123
124 check_stack_overflow(irq);
125
126 /*
127 * Some hardware gives randomly wrong interrupts. Rather
128 * than crashing, do something sensible.
129 */
130 if (irq >= NR_IRQS)
131 handle_bad_irq(irq, &bad_irq_desc);
132 else
133 generic_handle_irq(irq);
134
135 maybe_lower_to_irq14();
136
137 irq_exit();
138
139 set_irq_regs(old_regs);
140 }
141
init_IRQ(void)142 void __init init_IRQ(void)
143 {
144 init_arch_irq();
145
146 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
147 /* Now that evt_ivhw is set up, turn this on */
148 trace_buff_offset = 0;
149 bfin_write_TBUFCTL(BFIN_TRACE_ON);
150 printk(KERN_INFO "Hardware Trace expanded to %ik\n",
151 1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
152 #endif
153 }
154