lsi53c895a: add optional external IRQ via qdev

On some early machines the on-board PCI devices IRQs are wired directly to
the interrupt controller instead of via the PCI host bridge.

Add an optional external IRQ that if wired up via qdev will replace the
in-built PCI IRQ.
Signed-off-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NHervé Poussineau <hpoussin@reactos.org>
Tested-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/scsi/lsi53c895a.c

@@ -207,6 +207,7 @@ typedef struct {
     PCIDevice parent_obj;
     /*< public >*/
 
+    qemu_irq ext_irq;
     MemoryRegion mmio_io;
     MemoryRegion ram_io;
     MemoryRegion io_io;
@@ -443,9 +444,19 @@ static void lsi_stop_script(LSIState *s)
     s->istat1 &= ~LSI_ISTAT1_SRUN;
 }
 
-static void lsi_update_irq(LSIState *s)
+static void lsi_set_irq(LSIState *s, int level)
 {
     PCIDevice *d = PCI_DEVICE(s);
+
+    if (s->ext_irq) {
+        qemu_set_irq(s->ext_irq, level);
+    } else {
+        pci_set_irq(d, level);
+    }
+}
+
+static void lsi_update_irq(LSIState *s)
+{
     int level;
     static int last_level;
     lsi_request *p;
@@ -477,7 +488,7 @@ static void lsi_update_irq(LSIState *s)
                 level, s->dstat, s->sist1, s->sist0);
         last_level = level;
     }
-    pci_set_irq(d, level);
+    lsi_set_irq(s, level);
 
     if (!level && lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON)) {
         DPRINTF("Handled IRQs & disconnected, looking for pending "
@@ -2213,6 +2224,7 @@ static void lsi_scsi_realize(PCIDevice *dev, Error **errp)
                           "lsi-io", 256);
 
     address_space_init(&s->pci_io_as, pci_address_space_io(dev), "lsi-pci-io");
+    qdev_init_gpio_out(d, &s->ext_irq, 1);
 
     pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io_io);
     pci_register_bar(dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->mmio_io);