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