From f7c6e12e24a736f7f3f0bf2c4e34a598e3274130 Mon Sep 17 00:00:00 2001
From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Date: Wed, 20 Oct 2021 14:41:29 +0100
Subject: q800: route SONIC on-board Ethernet IRQ via nubus IRQ 9 in classic
 mode

When the hardware is operating in classic mode the SONIC on-board Ethernet IRQ is
routed to nubus IRQ 9 instead of directly to the CPU at level 3. This does not
affect the framebuffer which although it exists in slot 9, has its own
dedicated IRQ on the Quadra 800 hardware.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211020134131.4392-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/m68k/q800.c | 57 +++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 41 insertions(+), 16 deletions(-)

(limited to 'hw')

diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c
index 0093872..7a8de08 100644
--- a/hw/m68k/q800.c
+++ b/hw/m68k/q800.c
@@ -101,6 +101,7 @@ struct GLUEState {
     M68kCPU *cpu;
     uint8_t ipr;
     uint8_t auxmode;
+    qemu_irq irqs[1];
 };
 
 #define GLUE_IRQ_IN_VIA1       0
@@ -108,27 +109,40 @@ struct GLUEState {
 #define GLUE_IRQ_IN_SONIC      2
 #define GLUE_IRQ_IN_ESCC       3
 
+#define GLUE_IRQ_NUBUS_9       0
+
 static void GLUE_set_irq(void *opaque, int irq, int level)
 {
     GLUEState *s = opaque;
     int i;
 
-    switch (irq) {
-    case GLUE_IRQ_IN_VIA1:
-        irq = 5;
-        break;
-
-    case GLUE_IRQ_IN_VIA2:
-        irq = 1;
-        break;
-
-    case GLUE_IRQ_IN_SONIC:
-        irq = 2;
-        break;
-
-    case GLUE_IRQ_IN_ESCC:
-        irq = 3;
-        break;
+    if (s->auxmode) {
+        /* Classic mode */
+        switch (irq) {
+        case GLUE_IRQ_IN_SONIC:
+            /* Route to VIA2 instead */
+            qemu_set_irq(s->irqs[GLUE_IRQ_NUBUS_9], level);
+            return;
+        }
+    } else {
+        /* A/UX mode */
+        switch (irq) {
+        case GLUE_IRQ_IN_VIA1:
+            irq = 5;
+            break;
+
+        case GLUE_IRQ_IN_VIA2:
+            irq = 1;
+            break;
+
+        case GLUE_IRQ_IN_SONIC:
+            irq = 2;
+            break;
+
+        case GLUE_IRQ_IN_ESCC:
+            irq = 3;
+            break;
+        }
     }
 
     if (level) {
@@ -186,9 +200,12 @@ static Property glue_properties[] = {
 static void glue_init(Object *obj)
 {
     DeviceState *dev = DEVICE(obj);
+    GLUEState *s = GLUE(dev);
 
     qdev_init_gpio_in(dev, GLUE_set_irq, 8);
     qdev_init_gpio_in_named(dev, glue_auxmode_set_irq, "auxmode", 1);
+
+    qdev_init_gpio_out(dev, s->irqs, 1);
 }
 
 static void glue_class_init(ObjectClass *klass, void *data)
@@ -454,6 +471,14 @@ static void q800_init(MachineState *machine)
                                                      VIA2_NUBUS_IRQ_9 + i));
     }
 
+    /*
+     * Since the framebuffer in slot 0x9 uses a separate IRQ, wire the unused
+     * IRQ via GLUE for use by SONIC Ethernet in classic mode
+     */
+    qdev_connect_gpio_out(glue, GLUE_IRQ_NUBUS_9,
+                          qdev_get_gpio_in_named(via2_dev, "nubus-irq",
+                                                 VIA2_NUBUS_IRQ_9));
+
     nubus = &NUBUS_BRIDGE(dev)->bus;
 
     /* framebuffer in nubus slot #9 */
-- 
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