diff options
| author | Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> | 2022-03-05 15:09:56 +0000 |
|---|---|---|
| committer | Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> | 2022-03-09 09:28:28 +0000 |
| commit | b793b4ef8c862891c716cd163aaa7e4af0d697da (patch) | |
| tree | 1e67cac8ca64381fe32c6146edf09756cfa0f4ff /hw/misc/mac_via.c | |
| parent | 677a4725b1c49b139b00d8eaa932676ed8620931 (diff) | |
mos6522: implement edge-triggering for CA1/2 and CB1/2 control line IRQs
The mos6522 datasheet describes how the control lines IRQs are edge-triggered
according to the configuration in the PCR register. Implement the logic according
to the datasheet so that the interrupt bits in IFR are latched when the edge is
detected, and cleared when reading portA/portB or writing to IFR as necessary.
To maintain bisectibility this change also updates the SCSI, SCSI data, Nubus
and VIA2 60Hz/1Hz clocks in the q800 machine to be negative edge-triggered as
confirmed by the PCR programming in all of Linux, NetBSD and MacOS.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220305150957.5053-12-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Diffstat (limited to 'hw/misc/mac_via.c')
| -rw-r--r-- | hw/misc/mac_via.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c index d8b35e6ca6..525e38ce93 100644 --- a/hw/misc/mac_via.c +++ b/hw/misc/mac_via.c @@ -327,7 +327,9 @@ static void via1_sixty_hz(void *opaque) MOS6522State *s = MOS6522(v1s); qemu_irq irq = qdev_get_gpio_in(DEVICE(s), VIA1_IRQ_60HZ_BIT); - qemu_set_irq(irq, 1); + /* Negative edge trigger */ + qemu_irq_lower(irq); + qemu_irq_raise(irq); via1_sixty_hz_update(v1s); } @@ -338,7 +340,9 @@ static void via1_one_second(void *opaque) MOS6522State *s = MOS6522(v1s); qemu_irq irq = qdev_get_gpio_in(DEVICE(s), VIA1_IRQ_ONE_SECOND_BIT); - qemu_set_irq(irq, 1); + /* Negative edge trigger */ + qemu_irq_lower(irq); + qemu_irq_raise(irq); via1_one_second_update(v1s); } @@ -917,9 +921,11 @@ static uint64_t mos6522_q800_via2_read(void *opaque, hwaddr addr, unsigned size) * On a Q800 an emulated VIA2 is integrated into the onboard logic. The * expectation of most OSs is that the DRQ bit is live, rather than * latched as it would be on a real VIA so do the same here. + * + * Note: DRQ is negative edge triggered */ val &= ~VIA2_IRQ_SCSI_DATA; - val |= (ms->last_irq_levels & VIA2_IRQ_SCSI_DATA); + val |= (~ms->last_irq_levels & VIA2_IRQ_SCSI_DATA); break; } @@ -1146,7 +1152,8 @@ static void via2_nubus_irq_request(void *opaque, int n, int level) s->a |= (1 << n); } - qemu_set_irq(irq, level); + /* Negative edge trigger */ + qemu_set_irq(irq, !level); } static void mos6522_q800_via2_init(Object *obj) |