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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/arch/h8300/kernel/irq.c
4  *
5  * Copyright 2014-2015 Yoshinori Sato <ysato@users.sourceforge.jp>
6  */
7 
8 #include <linux/init.h>
9 #include <linux/interrupt.h>
10 #include <linux/irq.h>
11 #include <linux/irqdomain.h>
12 #include <linux/of_irq.h>
13 #include <asm/traps.h>
14 
15 #ifdef CONFIG_RAMKERNEL
16 typedef void (*h8300_vector)(void);
17 
18 static const h8300_vector __initconst trap_table[] = {
19 	0, 0, 0, 0,
20 	_trace_break,
21 	0, 0,
22 	_nmi,
23 	_system_call,
24 	0, 0,
25 	_trace_break,
26 };
27 
get_vector_address(void)28 static unsigned long __init *get_vector_address(void)
29 {
30 	unsigned long *rom_vector = CPU_VECTOR;
31 	unsigned long base, tmp;
32 	int vec_no;
33 
34 	base = rom_vector[EXT_IRQ0] & ADDR_MASK;
35 
36 	/* check romvector format */
37 	for (vec_no = EXT_IRQ0 + 1; vec_no <= EXT_IRQ0+EXT_IRQS; vec_no++) {
38 		if ((base+(vec_no - EXT_IRQ0)*4) !=
39 		    (rom_vector[vec_no] & ADDR_MASK))
40 			return NULL;
41 	}
42 
43 	/* ramvector base address */
44 	base -= EXT_IRQ0*4;
45 
46 	/* writerble? */
47 	tmp = ~(*(volatile unsigned long *)base);
48 	(*(volatile unsigned long *)base) = tmp;
49 	if ((*(volatile unsigned long *)base) != tmp)
50 		return NULL;
51 	return (unsigned long *)base;
52 }
53 
setup_vector(void)54 static void __init setup_vector(void)
55 {
56 	int i;
57 	unsigned long *ramvec, *ramvec_p;
58 	const h8300_vector *trap_entry;
59 
60 	ramvec = get_vector_address();
61 	if (ramvec == NULL)
62 		panic("interrupt vector serup failed.");
63 	else
64 		pr_debug("virtual vector at 0x%p\n", ramvec);
65 
66 	/* create redirect table */
67 	ramvec_p = ramvec;
68 	trap_entry = trap_table;
69 	for (i = 0; i < NR_IRQS; i++) {
70 		if (i < 12) {
71 			if (*trap_entry)
72 				*ramvec_p = VECTOR(*trap_entry);
73 			ramvec_p++;
74 			trap_entry++;
75 		} else
76 			*ramvec_p++ = REDIRECT(_interrupt_entry);
77 	}
78 	_interrupt_redirect_table = ramvec;
79 }
80 #else
setup_vector(void)81 void setup_vector(void)
82 {
83 	/* noting do */
84 }
85 #endif
86 
init_IRQ(void)87 void __init init_IRQ(void)
88 {
89 	setup_vector();
90 	irqchip_init();
91 }
92 
do_IRQ(int irq)93 asmlinkage void do_IRQ(int irq)
94 {
95 	irq_enter();
96 	generic_handle_irq(irq);
97 	irq_exit();
98 }
99