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
19 static atomic_t irq_err_count;
ack_bad_irq(unsigned int irq)20 void 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
26 static 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
arch_show_interrupts(struct seq_file * p,int prec)37 int 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
check_stack_overflow(int irq)51 static 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
check_stack_overflow(int irq)63 static inline void check_stack_overflow(int irq) { }
64 #endif
65
66 #ifndef CONFIG_IPIPE
maybe_lower_to_irq14(void)67 static 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
maybe_lower_to_irq14(void)86 static 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
asm_do_IRQ(unsigned int irq,struct pt_regs * regs)97 asmlinkage 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(&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
init_IRQ(void)121 void __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