1/*
2 *  linux/arch/m68k/amiga/cia.c - CIA support
3 *
4 *  Copyright (C) 1996 Roman Zippel
5 *
6 *  The concept of some functions bases on the original Amiga OS function
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License.  See the file COPYING in the main directory of this archive
10 * for more details.
11 */
12
13#include <linux/types.h>
14#include <linux/kernel.h>
15#include <linux/sched.h>
16#include <linux/errno.h>
17#include <linux/kernel_stat.h>
18#include <linux/init.h>
19#include <linux/seq_file.h>
20#include <linux/interrupt.h>
21#include <linux/irq.h>
22
23#include <asm/irq.h>
24#include <asm/amigahw.h>
25#include <asm/amigaints.h>
26
27struct ciabase {
28	volatile struct CIA *cia;
29	unsigned char icr_mask, icr_data;
30	unsigned short int_mask;
31	int handler_irq, cia_irq, server_irq;
32	char *name;
33} ciaa_base = {
34	.cia		= &ciaa,
35	.int_mask	= IF_PORTS,
36	.handler_irq	= IRQ_AMIGA_PORTS,
37	.cia_irq	= IRQ_AMIGA_CIAA,
38	.name		= "CIAA"
39}, ciab_base = {
40	.cia		= &ciab,
41	.int_mask	= IF_EXTER,
42	.handler_irq	= IRQ_AMIGA_EXTER,
43	.cia_irq	= IRQ_AMIGA_CIAB,
44	.name		= "CIAB"
45};
46
47/*
48 *  Cause or clear CIA interrupts, return old interrupt status.
49 */
50
51unsigned char cia_set_irq(struct ciabase *base, unsigned char mask)
52{
53	unsigned char old;
54
55	old = (base->icr_data |= base->cia->icr);
56	if (mask & CIA_ICR_SETCLR)
57		base->icr_data |= mask;
58	else
59		base->icr_data &= ~mask;
60	if (base->icr_data & base->icr_mask)
61		amiga_custom.intreq = IF_SETCLR | base->int_mask;
62	return old & base->icr_mask;
63}
64
65/*
66 *  Enable or disable CIA interrupts, return old interrupt mask,
67 */
68
69unsigned char cia_able_irq(struct ciabase *base, unsigned char mask)
70{
71	unsigned char old;
72
73	old = base->icr_mask;
74	base->icr_data |= base->cia->icr;
75	base->cia->icr = mask;
76	if (mask & CIA_ICR_SETCLR)
77		base->icr_mask |= mask;
78	else
79		base->icr_mask &= ~mask;
80	base->icr_mask &= CIA_ICR_ALL;
81	if (base->icr_data & base->icr_mask)
82		amiga_custom.intreq = IF_SETCLR | base->int_mask;
83	return old;
84}
85
86static irqreturn_t cia_handler(int irq, void *dev_id)
87{
88	struct ciabase *base = dev_id;
89	int mach_irq;
90	unsigned char ints;
91	unsigned long flags;
92
93	/* Interrupts get disabled while the timer irq flag is cleared and
94	 * the timer interrupt serviced.
95	 */
96	mach_irq = base->cia_irq;
97	local_irq_save(flags);
98	ints = cia_set_irq(base, CIA_ICR_ALL);
99	amiga_custom.intreq = base->int_mask;
100	if (ints & 1)
101		generic_handle_irq(mach_irq);
102	local_irq_restore(flags);
103	mach_irq++, ints >>= 1;
104	for (; ints; mach_irq++, ints >>= 1) {
105		if (ints & 1)
106			generic_handle_irq(mach_irq);
107	}
108	return IRQ_HANDLED;
109}
110
111static void cia_irq_enable(struct irq_data *data)
112{
113	unsigned int irq = data->irq;
114	unsigned char mask;
115
116	if (irq >= IRQ_AMIGA_CIAB) {
117		mask = 1 << (irq - IRQ_AMIGA_CIAB);
118		cia_set_irq(&ciab_base, mask);
119		cia_able_irq(&ciab_base, CIA_ICR_SETCLR | mask);
120	} else {
121		mask = 1 << (irq - IRQ_AMIGA_CIAA);
122		cia_set_irq(&ciaa_base, mask);
123		cia_able_irq(&ciaa_base, CIA_ICR_SETCLR | mask);
124	}
125}
126
127static void cia_irq_disable(struct irq_data *data)
128{
129	unsigned int irq = data->irq;
130
131	if (irq >= IRQ_AMIGA_CIAB)
132		cia_able_irq(&ciab_base, 1 << (irq - IRQ_AMIGA_CIAB));
133	else
134		cia_able_irq(&ciaa_base, 1 << (irq - IRQ_AMIGA_CIAA));
135}
136
137static struct irq_chip cia_irq_chip = {
138	.name		= "cia",
139	.irq_enable	= cia_irq_enable,
140	.irq_disable	= cia_irq_disable,
141};
142
143/*
144 * Override auto irq 2 & 6 and use them as general chain
145 * for external interrupts, we link the CIA interrupt sources
146 * into this chain.
147 */
148
149static void auto_irq_enable(struct irq_data *data)
150{
151	switch (data->irq) {
152	case IRQ_AUTO_2:
153		amiga_custom.intena = IF_SETCLR | IF_PORTS;
154		break;
155	case IRQ_AUTO_6:
156		amiga_custom.intena = IF_SETCLR | IF_EXTER;
157		break;
158	}
159}
160
161static void auto_irq_disable(struct irq_data *data)
162{
163	switch (data->irq) {
164	case IRQ_AUTO_2:
165		amiga_custom.intena = IF_PORTS;
166		break;
167	case IRQ_AUTO_6:
168		amiga_custom.intena = IF_EXTER;
169		break;
170	}
171}
172
173static struct irq_chip auto_irq_chip = {
174	.name		= "auto",
175	.irq_enable	= auto_irq_enable,
176	.irq_disable	= auto_irq_disable,
177};
178
179void __init cia_init_IRQ(struct ciabase *base)
180{
181	m68k_setup_irq_controller(&cia_irq_chip, handle_simple_irq,
182				  base->cia_irq, CIA_IRQS);
183
184	/* clear any pending interrupt and turn off all interrupts */
185	cia_set_irq(base, CIA_ICR_ALL);
186	cia_able_irq(base, CIA_ICR_ALL);
187
188	/* override auto int and install CIA handler */
189	m68k_setup_irq_controller(&auto_irq_chip, handle_simple_irq,
190				  base->handler_irq, 1);
191	m68k_irq_startup_irq(base->handler_irq);
192	if (request_irq(base->handler_irq, cia_handler, IRQF_SHARED,
193			base->name, base))
194		pr_err("Couldn't register %s interrupt\n", base->name);
195}
196