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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Macintosh interrupts
+ *
+ * General design:
+ * In contrary to the Amiga and Atari platforms, the Mac hardware seems to
+ * exclusively use the autovector interrupts (the 'generic level0-level7'
+ * interrupts with exception vectors 0x19-0x1f). The following interrupt levels
+ * are used:
+ * 1 - VIA1
+ * - slot 0: one second interrupt (CA2)
+ * - slot 1: VBlank (CA1)
+ * - slot 2: ADB data ready (SR full)
+ * - slot 3: ADB data (CB2)
+ * - slot 4: ADB clock (CB1)
+ * - slot 5: timer 2
+ * - slot 6: timer 1
+ * - slot 7: status of IRQ; signals 'any enabled int.'
+ *
+ * 2 - VIA2 or RBV
+ * - slot 0: SCSI DRQ (CA2)
+ * - slot 1: NUBUS IRQ (CA1) need to read port A to find which
+ * - slot 2: /EXP IRQ (only on IIci)
+ * - slot 3: SCSI IRQ (CB2)
+ * - slot 4: ASC IRQ (CB1)
+ * - slot 5: timer 2 (not on IIci)
+ * - slot 6: timer 1 (not on IIci)
+ * - slot 7: status of IRQ; signals 'any enabled int.'
+ *
+ * Levels 3-6 vary by machine type. For VIA or RBV Macintoshes:
+ *
+ * 3 - unused (?)
+ *
+ * 4 - SCC
+ *
+ * 5 - unused (?)
+ * [serial errors or special conditions seem to raise level 6
+ * interrupts on some models (LC4xx?)]
+ *
+ * 6 - off switch (?)
+ *
+ * Machines with Quadra-like VIA hardware, except PSC and PMU machines, support
+ * an alternate interrupt mapping, as used by A/UX. It spreads ethernet and
+ * sound out to their own autovector IRQs and gives VIA1 a higher priority:
+ *
+ * 1 - unused (?)
+ *
+ * 3 - on-board SONIC
+ *
+ * 5 - Apple Sound Chip (ASC)
+ *
+ * 6 - VIA1
+ *
+ * For OSS Macintoshes (IIfx only), we apply an interrupt mapping similar to
+ * the Quadra (A/UX) mapping:
+ *
+ * 1 - ISM IOP (ADB)
+ *
+ * 2 - SCSI
+ *
+ * 3 - NuBus
+ *
+ * 4 - SCC IOP
+ *
+ * 6 - VIA1
+ *
+ * For PSC Macintoshes (660AV, 840AV):
+ *
+ * 3 - PSC level 3
+ * - slot 0: MACE
+ *
+ * 4 - PSC level 4
+ * - slot 1: SCC channel A interrupt
+ * - slot 2: SCC channel B interrupt
+ * - slot 3: MACE DMA
+ *
+ * 5 - PSC level 5
+ *
+ * 6 - PSC level 6
+ *
+ * Finally we have good 'ole level 7, the non-maskable interrupt:
+ *
+ * 7 - NMI (programmer's switch on the back of some Macs)
+ * Also RAM parity error on models which support it (IIc, IIfx?)
+ *
+ * The current interrupt logic looks something like this:
+ *
+ * - We install dispatchers for the autovector interrupts (1-7). These
+ * dispatchers are responsible for querying the hardware (the
+ * VIA/RBV/OSS/PSC chips) to determine the actual interrupt source. Using
+ * this information a machspec interrupt number is generated by placing the
+ * index of the interrupt hardware into the low three bits and the original
+ * autovector interrupt number in the upper 5 bits. The handlers for the
+ * resulting machspec interrupt are then called.
+ *
+ * - Nubus is a special case because its interrupts are hidden behind two
+ * layers of hardware. Nubus interrupts come in as index 1 on VIA #2,
+ * which translates to IRQ number 17. In this spot we install _another_
+ * dispatcher. This dispatcher finds the interrupting slot number (9-F) and
+ * then forms a new machspec interrupt number as above with the slot number
+ * minus 9 in the low three bits and the pseudo-level 7 in the upper five
+ * bits. The handlers for this new machspec interrupt number are then
+ * called. This puts Nubus interrupts into the range 56-62.
+ *
+ * - The Baboon interrupts (used on some PowerBooks) are an even more special
+ * case. They're hidden behind the Nubus slot $C interrupt thus adding a
+ * third layer of indirection. Why oh why did the Apple engineers do that?
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/delay.h>
+
+#include <asm/irq.h>
+#include <asm/macintosh.h>
+#include <asm/macints.h>
+#include <asm/mac_via.h>
+#include <asm/mac_psc.h>
+#include <asm/mac_oss.h>
+#include <asm/mac_iop.h>
+#include <asm/mac_baboon.h>
+#include <asm/hwtest.h>
+#include <asm/irq_regs.h>
+#include <asm/processor.h>
+
+static unsigned int mac_irq_startup(struct irq_data *);
+static void mac_irq_shutdown(struct irq_data *);
+
+static struct irq_chip mac_irq_chip = {
+ .name = "mac",
+ .irq_enable = mac_irq_enable,
+ .irq_disable = mac_irq_disable,
+ .irq_startup = mac_irq_startup,
+ .irq_shutdown = mac_irq_shutdown,
+};
+
+static irqreturn_t mac_nmi_handler(int irq, void *dev_id)
+{
+ static volatile int in_nmi;
+
+ if (in_nmi)
+ return IRQ_HANDLED;
+ in_nmi = 1;
+
+ pr_info("Non-Maskable Interrupt\n");
+ show_registers(get_irq_regs());
+
+ in_nmi = 0;
+ return IRQ_HANDLED;
+}
+
+void __init mac_init_IRQ(void)
+{
+ m68k_setup_irq_controller(&mac_irq_chip, handle_simple_irq, IRQ_USER,
+ NUM_MAC_SOURCES - IRQ_USER);
+
+ /*
+ * Now register the handlers for the master IRQ handlers
+ * at levels 1-7. Most of the work is done elsewhere.
+ */
+
+ if (oss_present)
+ oss_register_interrupts();
+ else
+ via_register_interrupts();
+ if (psc)
+ psc_register_interrupts();
+ if (baboon_present)
+ baboon_register_interrupts();
+ iop_register_interrupts();
+ if (request_irq(IRQ_AUTO_7, mac_nmi_handler, 0, "NMI",
+ mac_nmi_handler))
+ pr_err("Couldn't register NMI\n");
+}
+
+/*
+ * mac_irq_enable - enable an interrupt source
+ * mac_irq_disable - disable an interrupt source
+ *
+ * These routines are just dispatchers to the VIA/OSS/PSC routines.
+ */
+
+void mac_irq_enable(struct irq_data *data)
+{
+ int irq = data->irq;
+ int irq_src = IRQ_SRC(irq);
+
+ switch(irq_src) {
+ case 1:
+ case 2:
+ case 7:
+ if (oss_present)
+ oss_irq_enable(irq);
+ else
+ via_irq_enable(irq);
+ break;
+ case 3:
+ case 4:
+ case 5:
+ case 6:
+ if (psc)
+ psc_irq_enable(irq);
+ else if (oss_present)
+ oss_irq_enable(irq);
+ break;
+ case 8:
+ if (baboon_present)
+ baboon_irq_enable(irq);
+ break;
+ }
+}
+
+void mac_irq_disable(struct irq_data *data)
+{
+ int irq = data->irq;
+ int irq_src = IRQ_SRC(irq);
+
+ switch(irq_src) {
+ case 1:
+ case 2:
+ case 7:
+ if (oss_present)
+ oss_irq_disable(irq);
+ else
+ via_irq_disable(irq);
+ break;
+ case 3:
+ case 4:
+ case 5:
+ case 6:
+ if (psc)
+ psc_irq_disable(irq);
+ else if (oss_present)
+ oss_irq_disable(irq);
+ break;
+ case 8:
+ if (baboon_present)
+ baboon_irq_disable(irq);
+ break;
+ }
+}
+
+static unsigned int mac_irq_startup(struct irq_data *data)
+{
+ int irq = data->irq;
+
+ if (IRQ_SRC(irq) == 7 && !oss_present)
+ via_nubus_irq_startup(irq);
+ else
+ mac_irq_enable(data);
+
+ return 0;
+}
+
+static void mac_irq_shutdown(struct irq_data *data)
+{
+ int irq = data->irq;
+
+ if (IRQ_SRC(irq) == 7 && !oss_present)
+ via_nubus_irq_shutdown(irq);
+ else
+ mac_irq_disable(data);
+}