xref: /openbmc/linux/arch/x86/kernel/irqinit.c (revision 5a244f48)
1 #include <linux/linkage.h>
2 #include <linux/errno.h>
3 #include <linux/signal.h>
4 #include <linux/sched.h>
5 #include <linux/ioport.h>
6 #include <linux/interrupt.h>
7 #include <linux/timex.h>
8 #include <linux/random.h>
9 #include <linux/kprobes.h>
10 #include <linux/init.h>
11 #include <linux/kernel_stat.h>
12 #include <linux/device.h>
13 #include <linux/bitops.h>
14 #include <linux/acpi.h>
15 #include <linux/io.h>
16 #include <linux/delay.h>
17 
18 #include <linux/atomic.h>
19 #include <asm/timer.h>
20 #include <asm/hw_irq.h>
21 #include <asm/pgtable.h>
22 #include <asm/desc.h>
23 #include <asm/apic.h>
24 #include <asm/setup.h>
25 #include <asm/i8259.h>
26 #include <asm/traps.h>
27 #include <asm/prom.h>
28 
29 /*
30  * ISA PIC or low IO-APIC triggered (INTA-cycle or APIC) interrupts:
31  * (these are usually mapped to vectors 0x30-0x3f)
32  */
33 
34 /*
35  * The IO-APIC gives us many more interrupt sources. Most of these
36  * are unused but an SMP system is supposed to have enough memory ...
37  * sometimes (mostly wrt. hw bugs) we get corrupted vectors all
38  * across the spectrum, so we really want to be prepared to get all
39  * of these. Plus, more powerful systems might have more than 64
40  * IO-APIC registers.
41  *
42  * (these are usually mapped into the 0x30-0xff vector range)
43  */
44 
45 /*
46  * IRQ2 is cascade interrupt to second interrupt controller
47  */
48 static struct irqaction irq2 = {
49 	.handler = no_action,
50 	.name = "cascade",
51 	.flags = IRQF_NO_THREAD,
52 };
53 
54 DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
55 	[0 ... NR_VECTORS - 1] = VECTOR_UNUSED,
56 };
57 
58 void __init init_ISA_irqs(void)
59 {
60 	struct irq_chip *chip = legacy_pic->chip;
61 	int i;
62 
63 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC)
64 	init_bsp_APIC();
65 #endif
66 	legacy_pic->init(0);
67 
68 	for (i = 0; i < nr_legacy_irqs(); i++)
69 		irq_set_chip_and_handler(i, chip, handle_level_irq);
70 }
71 
72 void __init init_IRQ(void)
73 {
74 	int i;
75 
76 	/*
77 	 * On cpu 0, Assign ISA_IRQ_VECTOR(irq) to IRQ 0..15.
78 	 * If these IRQ's are handled by legacy interrupt-controllers like PIC,
79 	 * then this configuration will likely be static after the boot. If
80 	 * these IRQ's are handled by more mordern controllers like IO-APIC,
81 	 * then this vector space can be freed and re-used dynamically as the
82 	 * irq's migrate etc.
83 	 */
84 	for (i = 0; i < nr_legacy_irqs(); i++)
85 		per_cpu(vector_irq, 0)[ISA_IRQ_VECTOR(i)] = irq_to_desc(i);
86 
87 	x86_init.irqs.intr_init();
88 }
89 
90 void __init native_init_IRQ(void)
91 {
92 	/* Execute any quirks before the call gates are initialised: */
93 	x86_init.irqs.pre_vector_init();
94 
95 	idt_setup_apic_and_irq_gates();
96 
97 	if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs())
98 		setup_irq(2, &irq2);
99 
100 	irq_ctx_init(smp_processor_id());
101 }
102