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