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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Macintosh interrupts
4 *
5 * General design:
6 * In contrary to the Amiga and Atari platforms, the Mac hardware seems to
7 * exclusively use the autovector interrupts (the 'generic level0-level7'
8 * interrupts with exception vectors 0x19-0x1f). The following interrupt levels
9 * are used:
10 * 1 - VIA1
11 * - slot 0: one second interrupt (CA2)
12 * - slot 1: VBlank (CA1)
13 * - slot 2: ADB data ready (SR full)
14 * - slot 3: ADB data (CB2)
15 * - slot 4: ADB clock (CB1)
16 * - slot 5: timer 2
17 * - slot 6: timer 1
18 * - slot 7: status of IRQ; signals 'any enabled int.'
19 *
20 * 2 - VIA2 or RBV
21 * - slot 0: SCSI DRQ (CA2)
22 * - slot 1: NUBUS IRQ (CA1) need to read port A to find which
23 * - slot 2: /EXP IRQ (only on IIci)
24 * - slot 3: SCSI IRQ (CB2)
25 * - slot 4: ASC IRQ (CB1)
26 * - slot 5: timer 2 (not on IIci)
27 * - slot 6: timer 1 (not on IIci)
28 * - slot 7: status of IRQ; signals 'any enabled int.'
29 *
30 * Levels 3-6 vary by machine type. For VIA or RBV Macintoshes:
31 *
32 * 3 - unused (?)
33 *
34 * 4 - SCC
35 *
36 * 5 - unused (?)
37 * [serial errors or special conditions seem to raise level 6
38 * interrupts on some models (LC4xx?)]
39 *
40 * 6 - off switch (?)
41 *
42 * Machines with Quadra-like VIA hardware, except PSC and PMU machines, support
43 * an alternate interrupt mapping, as used by A/UX. It spreads ethernet and
44 * sound out to their own autovector IRQs and gives VIA1 a higher priority:
45 *
46 * 1 - unused (?)
47 *
48 * 3 - on-board SONIC
49 *
50 * 5 - Apple Sound Chip (ASC)
51 *
52 * 6 - VIA1
53 *
54 * For OSS Macintoshes (IIfx only), we apply an interrupt mapping similar to
55 * the Quadra (A/UX) mapping:
56 *
57 * 1 - ISM IOP (ADB)
58 *
59 * 2 - SCSI
60 *
61 * 3 - NuBus
62 *
63 * 4 - SCC IOP
64 *
65 * 6 - VIA1
66 *
67 * For PSC Macintoshes (660AV, 840AV):
68 *
69 * 3 - PSC level 3
70 * - slot 0: MACE
71 *
72 * 4 - PSC level 4
73 * - slot 1: SCC channel A interrupt
74 * - slot 2: SCC channel B interrupt
75 * - slot 3: MACE DMA
76 *
77 * 5 - PSC level 5
78 *
79 * 6 - PSC level 6
80 *
81 * Finally we have good 'ole level 7, the non-maskable interrupt:
82 *
83 * 7 - NMI (programmer's switch on the back of some Macs)
84 * Also RAM parity error on models which support it (IIc, IIfx?)
85 *
86 * The current interrupt logic looks something like this:
87 *
88 * - We install dispatchers for the autovector interrupts (1-7). These
89 * dispatchers are responsible for querying the hardware (the
90 * VIA/RBV/OSS/PSC chips) to determine the actual interrupt source. Using
91 * this information a machspec interrupt number is generated by placing the
92 * index of the interrupt hardware into the low three bits and the original
93 * autovector interrupt number in the upper 5 bits. The handlers for the
94 * resulting machspec interrupt are then called.
95 *
96 * - Nubus is a special case because its interrupts are hidden behind two
97 * layers of hardware. Nubus interrupts come in as index 1 on VIA #2,
98 * which translates to IRQ number 17. In this spot we install _another_
99 * dispatcher. This dispatcher finds the interrupting slot number (9-F) and
100 * then forms a new machspec interrupt number as above with the slot number
101 * minus 9 in the low three bits and the pseudo-level 7 in the upper five
102 * bits. The handlers for this new machspec interrupt number are then
103 * called. This puts Nubus interrupts into the range 56-62.
104 *
105 * - The Baboon interrupts (used on some PowerBooks) are an even more special
106 * case. They're hidden behind the Nubus slot $C interrupt thus adding a
107 * third layer of indirection. Why oh why did the Apple engineers do that?
108 *
109 */
110
111#include <linux/types.h>
112#include <linux/kernel.h>
113#include <linux/sched.h>
114#include <linux/sched/debug.h>
115#include <linux/interrupt.h>
116#include <linux/irq.h>
117#include <linux/delay.h>
118
119#include <asm/irq.h>
120#include <asm/macintosh.h>
121#include <asm/macints.h>
122#include <asm/mac_via.h>
123#include <asm/mac_psc.h>
124#include <asm/mac_oss.h>
125#include <asm/mac_iop.h>
126#include <asm/mac_baboon.h>
127#include <asm/hwtest.h>
128#include <asm/irq_regs.h>
129#include <asm/processor.h>
130
131static unsigned int mac_irq_startup(struct irq_data *);
132static void mac_irq_shutdown(struct irq_data *);
133
134static struct irq_chip mac_irq_chip = {
135 .name = "mac",
136 .irq_enable = mac_irq_enable,
137 .irq_disable = mac_irq_disable,
138 .irq_startup = mac_irq_startup,
139 .irq_shutdown = mac_irq_shutdown,
140};
141
142static irqreturn_t mac_nmi_handler(int irq, void *dev_id)
143{
144 static volatile int in_nmi;
145
146 if (in_nmi)
147 return IRQ_HANDLED;
148 in_nmi = 1;
149
150 pr_info("Non-Maskable Interrupt\n");
151 show_registers(get_irq_regs());
152
153 in_nmi = 0;
154 return IRQ_HANDLED;
155}
156
157void __init mac_init_IRQ(void)
158{
159 m68k_setup_irq_controller(&mac_irq_chip, handle_simple_irq, IRQ_USER,
160 NUM_MAC_SOURCES - IRQ_USER);
161
162 /*
163 * Now register the handlers for the master IRQ handlers
164 * at levels 1-7. Most of the work is done elsewhere.
165 */
166
167 if (oss_present)
168 oss_register_interrupts();
169 else
170 via_register_interrupts();
171 if (psc)
172 psc_register_interrupts();
173 if (baboon_present)
174 baboon_register_interrupts();
175 iop_register_interrupts();
176 if (request_irq(IRQ_AUTO_7, mac_nmi_handler, 0, "NMI",
177 mac_nmi_handler))
178 pr_err("Couldn't register NMI\n");
179}
180
181/*
182 * mac_irq_enable - enable an interrupt source
183 * mac_irq_disable - disable an interrupt source
184 *
185 * These routines are just dispatchers to the VIA/OSS/PSC routines.
186 */
187
188void mac_irq_enable(struct irq_data *data)
189{
190 int irq = data->irq;
191 int irq_src = IRQ_SRC(irq);
192
193 switch(irq_src) {
194 case 1:
195 case 2:
196 case 7:
197 if (oss_present)
198 oss_irq_enable(irq);
199 else
200 via_irq_enable(irq);
201 break;
202 case 3:
203 case 4:
204 case 5:
205 case 6:
206 if (psc)
207 psc_irq_enable(irq);
208 else if (oss_present)
209 oss_irq_enable(irq);
210 break;
211 case 8:
212 if (baboon_present)
213 baboon_irq_enable(irq);
214 break;
215 }
216}
217
218void mac_irq_disable(struct irq_data *data)
219{
220 int irq = data->irq;
221 int irq_src = IRQ_SRC(irq);
222
223 switch(irq_src) {
224 case 1:
225 case 2:
226 case 7:
227 if (oss_present)
228 oss_irq_disable(irq);
229 else
230 via_irq_disable(irq);
231 break;
232 case 3:
233 case 4:
234 case 5:
235 case 6:
236 if (psc)
237 psc_irq_disable(irq);
238 else if (oss_present)
239 oss_irq_disable(irq);
240 break;
241 case 8:
242 if (baboon_present)
243 baboon_irq_disable(irq);
244 break;
245 }
246}
247
248static unsigned int mac_irq_startup(struct irq_data *data)
249{
250 int irq = data->irq;
251
252 if (IRQ_SRC(irq) == 7 && !oss_present)
253 via_nubus_irq_startup(irq);
254 else
255 mac_irq_enable(data);
256
257 return 0;
258}
259
260static void mac_irq_shutdown(struct irq_data *data)
261{
262 int irq = data->irq;
263
264 if (IRQ_SRC(irq) == 7 && !oss_present)
265 via_nubus_irq_shutdown(irq);
266 else
267 mac_irq_disable(data);
268}