[Qemu-ppc] [PATCH v2 3/3] 40p: add fixed IRQ routing for LSI SCSI device

[Mark Cave-Ayland]

Whilst the PReP specification describes how all PCI IRQs are routed via IRQ
15 on the interrupt controller, the real 40p machine has routing quirk in
that the LSI SCSI device is routed to IRQ 13.

This is implemented using a little hack: the existing IRQ routing code uses
(irq_num + (pci_dev->devfn >> 3)) & 1 to give the PCI interrupt pin, where
the "& 1" ensures that the only pins A and B (0 and 1) will ever be used.

Rather than fix the mask to "& 3" we leave the existing routing above as-is
and then force the LSI SCSI device to use pin C (2). This enables us to
route pin 2 permanantly to IRQ 13 since the LSI SCSI device will be its
only user.

Signed-off-by: Mark Cave-Ayland <address@hidden>
---
 hw/pci-host/prep.c | 35 +++++++++++++++++++++++++++++++++--
 hw/ppc/prep.c      | 10 +++++++---
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index b1b6b16bad..87270605b5 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -58,6 +58,7 @@ typedef struct PRePPCIState {
 
     qemu_or_irq *or_irq;
     qemu_irq pci_irqs[PCI_NUM_PINS];
+    qemu_irq scsi_irq;
     PCIBus pci_bus;
     AddressSpace pci_io_as;
     MemoryRegion pci_io;
@@ -192,14 +193,41 @@ static const MemoryRegionOps raven_io_ops = {
 
 static int raven_map_irq(PCIDevice *pci_dev, int irq_num)
 {
-    return (irq_num + (pci_dev->devfn >> 3)) & 1;
+    switch (pci_dev->devfn) {
+    case PCI_DEVFN(1, 0):
+        /* Whilst legacy PReP machine exists we need to make
+         * sure that this fixed interrupt routing is 40p only */
+        if (strcmp(object_get_typename(OBJECT(pci_dev)),
+                                       "lsi53c810") == 0) {
+            /* LSI SCSI */
+            return 2;
+        } else {
+            /* Normal PCI IRQ mapping */
+            return (irq_num + (pci_dev->devfn >> 3)) & 1;
+        }
+    default:
+        /* Normal PCI IRQ mapping */
+        return (irq_num + (pci_dev->devfn >> 3)) & 1;
+    }
 }
 
 static void raven_set_irq(void *opaque, int irq_num, int level)
 {
     PREPPCIState *s = opaque;
 
-    qemu_set_irq(s->pci_irqs[irq_num], level);
+    if (s->is_legacy_prep) {
+        qemu_set_irq(s->pci_irqs[irq_num], level);
+    } else {
+        switch (irq_num) {
+        case 2:
+            /* LSI SCSI */
+            qemu_set_irq(s->scsi_irq, level);
+            break;
+        default:
+            /* Normal PCI IRQ mapping */
+            qemu_set_irq(s->pci_irqs[irq_num], level);
+        }
+    }
 }
 
 static AddressSpace *raven_pcihost_set_iommu(PCIBus *bus, void *opaque,
@@ -242,6 +270,9 @@ static void raven_pcihost_realizefn(DeviceState *d, Error 
**errp)
         for (i = 0; i < PCI_NUM_PINS; i++) {
             s->pci_irqs[i] = qdev_get_gpio_in(DEVICE(s->or_irq), i);
         }
+
+        /* 40p LSI SCSI has fixed routing via IRQ 13 */
+        sysbus_init_irq(dev, &s->scsi_irq);
     }
 
     qdev_init_gpio_in(d, raven_change_gpio, 1);
diff --git a/hw/ppc/prep.c b/hw/ppc/prep.c
index 615865e46c..0412a56d98 100644
--- a/hw/ppc/prep.c
+++ b/hw/ppc/prep.c
@@ -626,6 +626,7 @@ static void ibm_40p_init(MachineState *machine)
     Nvram *m48t59 = NULL;
     PCIBus *pci_bus;
     ISABus *isa_bus;
+    PCIDevice *pci;
     void *fw_cfg;
     int i;
     uint32_t kernel_base = 0, initrd_base = 0;
@@ -670,6 +671,7 @@ static void ibm_40p_init(MachineState *machine)
     qdev_connect_gpio_out(dev, 0,
                           cpu->env.irq_inputs[PPC6xx_INPUT_INT]);
     sysbus_connect_irq(pcihost, 0, qdev_get_gpio_in(dev, 15));
+    sysbus_connect_irq(pcihost, 1, qdev_get_gpio_in(dev, 13));
     isa_bus = ISA_BUS(qdev_get_child_bus(dev, "isa.0"));
 
     /* Memory controller */
@@ -700,9 +702,11 @@ static void ibm_40p_init(MachineState *machine)
         qdev_prop_set_uint32(dev, "equipment", 0xc0);
         qdev_init_nofail(dev);
 
-        dev = DEVICE(pci_create_simple(pci_bus, PCI_DEVFN(1, 0),
-                                       "lsi53c810"));
-        lsi53c8xx_handle_legacy_cmdline(dev);
+        pci = PCI_DEVICE(pci_create_simple(pci_bus, PCI_DEVFN(1, 0),
+                                           "lsi53c810"));
+        /* Interrupt pin C for fixed LSI SCSI IRQ routing */
+        pci->config[PCI_INTERRUPT_PIN] = 0x3;
+        lsi53c8xx_handle_legacy_cmdline(DEVICE(pci));
 
         /* XXX: s3-trio at PCI_DEVFN(2, 0) */
         pci_vga_init(pci_bus);
-- 
2.11.0