1/*
2 * arch/sh/kernel/cpu/irq/imask.c
3 *
4 * Copyright (C) 1999, 2000  Niibe Yutaka
5 *
6 * Simple interrupt handling using IMASK of SR register.
7 *
8 */
9/* NOTE: Will not work on level 15 */
10#include <linux/ptrace.h>
11#include <linux/errno.h>
12#include <linux/kernel_stat.h>
13#include <linux/signal.h>
14#include <linux/sched.h>
15#include <linux/interrupt.h>
16#include <linux/init.h>
17#include <linux/bitops.h>
18#include <linux/spinlock.h>
19#include <linux/cache.h>
20#include <linux/irq.h>
21#include <asm/system.h>
22#include <asm/irq.h>
23
24/* Bitmap of IRQ masked */
25static unsigned long imask_mask = 0x7fff;
26static int interrupt_priority = 0;
27
28static void enable_imask_irq(unsigned int irq);
29static void disable_imask_irq(unsigned int irq);
30static void shutdown_imask_irq(unsigned int irq);
31static void mask_and_ack_imask(unsigned int);
32static void end_imask_irq(unsigned int irq);
33
34#define IMASK_PRIORITY	15
35
36static unsigned int startup_imask_irq(unsigned int irq)
37{
38	/* Nothing to do */
39	return 0; /* never anything pending */
40}
41
42static struct hw_interrupt_type imask_irq_type = {
43	.typename = "SR.IMASK",
44	.startup = startup_imask_irq,
45	.shutdown = shutdown_imask_irq,
46	.enable = enable_imask_irq,
47	.disable = disable_imask_irq,
48	.ack = mask_and_ack_imask,
49	.end = end_imask_irq
50};
51
52void static inline set_interrupt_registers(int ip)
53{
54	unsigned long __dummy;
55
56	asm volatile(
57#ifdef CONFIG_CPU_HAS_SR_RB
58		     "ldc	%2, r6_bank\n\t"
59#endif
60		     "stc	sr, %0\n\t"
61		     "and	#0xf0, %0\n\t"
62		     "shlr2	%0\n\t"
63		     "cmp/eq	#0x3c, %0\n\t"
64		     "bt/s	1f	! CLI-ed\n\t"
65		     " stc	sr, %0\n\t"
66		     "and	%1, %0\n\t"
67		     "or	%2, %0\n\t"
68		     "ldc	%0, sr\n"
69		     "1:"
70		     : "=&z" (__dummy)
71		     : "r" (~0xf0), "r" (ip << 4)
72		     : "t");
73}
74
75static void disable_imask_irq(unsigned int irq)
76{
77	clear_bit(irq, &imask_mask);
78	if (interrupt_priority < IMASK_PRIORITY - irq)
79		interrupt_priority = IMASK_PRIORITY - irq;
80
81	set_interrupt_registers(interrupt_priority);
82}
83
84static void enable_imask_irq(unsigned int irq)
85{
86	set_bit(irq, &imask_mask);
87	interrupt_priority = IMASK_PRIORITY - ffz(imask_mask);
88
89	set_interrupt_registers(interrupt_priority);
90}
91
92static void mask_and_ack_imask(unsigned int irq)
93{
94	disable_imask_irq(irq);
95}
96
97static void end_imask_irq(unsigned int irq)
98{
99	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
100		enable_imask_irq(irq);
101}
102
103static void shutdown_imask_irq(unsigned int irq)
104{
105	/* Nothing to do */
106}
107
108void make_imask_irq(unsigned int irq)
109{
110	disable_irq_nosync(irq);
111	irq_desc[irq].chip = &imask_irq_type;
112	enable_irq(irq);
113}
114