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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>
extern void show_registers(struct pt_regs *);
irqreturn_t mac_nmi_handler(int, void *);
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,
};
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);
}
static volatile int in_nmi;
irqreturn_t mac_nmi_handler(int irq, void *dev_id)
{
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;
}
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