1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/sh/kernel/cpu/irq/imask.c
4 *
5 * Copyright (C) 1999, 2000 Niibe Yutaka
6 *
7 * Simple interrupt handling using IMASK of SR register.
8 *
9 */
10/* NOTE: Will not work on level 15 */
11#include <linux/ptrace.h>
12#include <linux/errno.h>
13#include <linux/kernel_stat.h>
14#include <linux/signal.h>
15#include <linux/sched.h>
16#include <linux/interrupt.h>
17#include <linux/init.h>
18#include <linux/bitops.h>
19#include <linux/spinlock.h>
20#include <linux/cache.h>
21#include <linux/irq.h>
22#include <linux/bitmap.h>
23#include <asm/irq.h>
24
25/* Bitmap of IRQ masked */
26#define IMASK_PRIORITY 15
27
28static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
29static int interrupt_priority;
30
31static inline void set_interrupt_registers(int ip)
32{
33 unsigned long __dummy;
34
35 asm volatile(
36#ifdef CONFIG_CPU_HAS_SR_RB
37 "ldc %2, r6_bank\n\t"
38#endif
39 "stc sr, %0\n\t"
40 "and #0xf0, %0\n\t"
41 "shlr2 %0\n\t"
42 "cmp/eq #0x3c, %0\n\t"
43 "bt/s 1f ! CLI-ed\n\t"
44 " stc sr, %0\n\t"
45 "and %1, %0\n\t"
46 "or %2, %0\n\t"
47 "ldc %0, sr\n"
48 "1:"
49 : "=&z" (__dummy)
50 : "r" (~0xf0), "r" (ip << 4)
51 : "t");
52}
53
54static void mask_imask_irq(struct irq_data *data)
55{
56 unsigned int irq = data->irq;
57
58 clear_bit(nr: irq, addr: imask_mask);
59 if (interrupt_priority < IMASK_PRIORITY - irq)
60 interrupt_priority = IMASK_PRIORITY - irq;
61 set_interrupt_registers(interrupt_priority);
62}
63
64static void unmask_imask_irq(struct irq_data *data)
65{
66 unsigned int irq = data->irq;
67
68 set_bit(nr: irq, addr: imask_mask);
69 interrupt_priority = IMASK_PRIORITY -
70 find_first_zero_bit(addr: imask_mask, IMASK_PRIORITY);
71 set_interrupt_registers(interrupt_priority);
72}
73
74static struct irq_chip imask_irq_chip = {
75 .name = "SR.IMASK",
76 .irq_mask = mask_imask_irq,
77 .irq_unmask = unmask_imask_irq,
78 .irq_mask_ack = mask_imask_irq,
79};
80
81void make_imask_irq(unsigned int irq)
82{
83 irq_set_chip_and_handler_name(irq, chip: &imask_irq_chip, handle: handle_level_irq,
84 name: "level");
85}
86

source code of linux/arch/sh/kernel/cpu/irq/imask.c