sun4m: don't connect two qemu_irqs directly to the same input

The sun4m board code connects both of the IRQ outputs of each ESCC to the
same slavio input qemu_irq. Connecting two qemu_irqs outputs directly to the
same input is not valid as it produces subtly wrong behaviour (for instance
if both the IRQ lines are high, and then one goes low, the PIC input will see
this as a high-to-low transition even though the second IRQ line should still
be holding it high).

This kind of wiring needs an explicitly created OR gate; add one.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20201219111934.5540-1-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Artyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

diff --git a/hw/sparc/Kconfig b/hw/sparc/Kconfig
index 91805afab66f2a1dac4cb33f34cc3bbedb6aa4ea..8dcb10086fdfbc647f6efd8d5c71d2658068f3d5 100644 (file)
--- a/hw/sparc/Kconfig
+++ b/hw/sparc/Kconfig
@@ -14,6 +14,7 @@ config SUN4M
     select M48T59
     select STP2000
     select CHRP_NVRAM
+    select OR_IRQ
 
 config LEON3
     bool

diff --git a/hw/sparc/sun4m.c b/hw/sparc/sun4m.c
index 8686371318262c6094bfd616fd0bb01583305eed..38ca1e33c7e714b504ce86e098b282547fc756bb 100644 (file)
--- a/hw/sparc/sun4m.c
+++ b/hw/sparc/sun4m.c
@@ -50,6 +50,7 @@
 #include "hw/misc/empty_slot.h"
 #include "hw/misc/unimp.h"
 #include "hw/irq.h"
+#include "hw/or-irq.h"
 #include "hw/loader.h"
 #include "elf.h"
 #include "trace.h"
@@ -848,7 +849,7 @@ static void sun4m_hw_init(const struct sun4m_hwdef *hwdef,
     uint32_t initrd_size;
     DriveInfo *fd[MAX_FD];
     FWCfgState *fw_cfg;
-    DeviceState *dev;
+    DeviceState *dev, *ms_kb_orgate, *serial_orgate;
     SysBusDevice *s;
     unsigned int smp_cpus = machine->smp.cpus;
     unsigned int max_cpus = machine->smp.max_cpus;
@@ -994,10 +995,16 @@ static void sun4m_hw_init(const struct sun4m_hwdef *hwdef,
     qdev_prop_set_uint32(dev, "chnAtype", escc_kbd);
     s = SYS_BUS_DEVICE(dev);
     sysbus_realize_and_unref(s, &error_fatal);
-    sysbus_connect_irq(s, 0, slavio_irq[14]);
-    sysbus_connect_irq(s, 1, slavio_irq[14]);
     sysbus_mmio_map(s, 0, hwdef->ms_kb_base);
 
+    /* Logically OR both its IRQs together */
+    ms_kb_orgate = DEVICE(object_new(TYPE_OR_IRQ));
+    object_property_set_int(OBJECT(ms_kb_orgate), "num-lines", 2, &error_fatal);
+    qdev_realize_and_unref(ms_kb_orgate, NULL, &error_fatal);
+    sysbus_connect_irq(s, 0, qdev_get_gpio_in(ms_kb_orgate, 0));
+    sysbus_connect_irq(s, 1, qdev_get_gpio_in(ms_kb_orgate, 1));
+    qdev_connect_gpio_out(DEVICE(ms_kb_orgate), 0, slavio_irq[14]);
+
     dev = qdev_new(TYPE_ESCC);
     qdev_prop_set_uint32(dev, "disabled", 0);
     qdev_prop_set_uint32(dev, "frequency", ESCC_CLOCK);
@@ -1009,10 +1016,17 @@ static void sun4m_hw_init(const struct sun4m_hwdef *hwdef,
 
     s = SYS_BUS_DEVICE(dev);
     sysbus_realize_and_unref(s, &error_fatal);
-    sysbus_connect_irq(s, 0, slavio_irq[15]);
-    sysbus_connect_irq(s, 1,  slavio_irq[15]);
     sysbus_mmio_map(s, 0, hwdef->serial_base);
 
+    /* Logically OR both its IRQs together */
+    serial_orgate = DEVICE(object_new(TYPE_OR_IRQ));
+    object_property_set_int(OBJECT(serial_orgate), "num-lines", 2,
+                            &error_fatal);
+    qdev_realize_and_unref(serial_orgate, NULL, &error_fatal);
+    sysbus_connect_irq(s, 0, qdev_get_gpio_in(serial_orgate, 0));
+    sysbus_connect_irq(s, 1, qdev_get_gpio_in(serial_orgate, 1));
+    qdev_connect_gpio_out(DEVICE(serial_orgate), 0, slavio_irq[15]);
+
     if (hwdef->apc_base) {
         apc_init(hwdef->apc_base, qemu_allocate_irq(cpu_halt_signal, NULL, 0));
     }