hw/alpha: Provide a PCI-ISA bridge device node

- Move initialization of the ISA bus from typhoon_init() to clipper_init();
  this apsect of device topology is really associated with the individual
  model, not the core logic chipset.  typhoon_init() now returns the IRQ
  to use for the output of the ISA PIC.

- In clipper_init(), instantiate an i82378 instance, and connect its
  PIC output to the ISA IRQ input provided by typhoon_init().  Remove
  the explicit instantiations of i8254 and i82374, as these devices
  are subsumed by the i82378.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Jason Thorpe <thorpej@me.com>
Message-Id: <20210616141538.25436-1-thorpej@me.com>
[rth: Remove direct dependencies on i82374, i8254, i8259.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

hw/alpha/Kconfig

@@ -3,9 +3,7 @@ config DP264
     imply PCI_DEVICES
     imply TEST_DEVICES
     imply E1000_PCI
-    select I82374
+    select I82378
-    select I8254
-    select I8259
     select IDE_CMD646
     select MC146818RTC
     select PCI

hw/alpha/alpha_sys.h

@@ -10,7 +10,7 @@
 #include "hw/intc/i8259.h"
 
 
-PCIBus *typhoon_init(MemoryRegion *, ISABus **, qemu_irq *, AlphaCPU *[4],
+PCIBus *typhoon_init(MemoryRegion *, qemu_irq *, qemu_irq *, AlphaCPU *[4],
                      pci_map_irq_fn, uint8_t devfn_min);
 
 /* alpha_pci.c.  */

hw/alpha/dp264.c

@@ -15,9 +15,7 @@
 #include "qemu/error-report.h"
 #include "hw/rtc/mc146818rtc.h"
 #include "hw/ide/pci.h"
-#include "hw/timer/i8254.h"
 #include "hw/isa/superio.h"
-#include "hw/dma/i8257.h"
 #include "net/net.h"
 #include "qemu/cutils.h"
 #include "qemu/datadir.h"
@@ -58,8 +56,10 @@ static void clipper_init(MachineState *machine)
     AlphaCPU *cpus[4];
     PCIBus *pci_bus;
     PCIDevice *pci_dev;
+    DeviceState *i82378_dev;
     ISABus *isa_bus;
     qemu_irq rtc_irq;
+    qemu_irq isa_irq;
     long size, i;
     char *palcode_filename;
     uint64_t palcode_entry;
@@ -90,14 +90,39 @@ static void clipper_init(MachineState *machine)
      * Init the chipset.  Because we're using CLIPPER IRQ mappings,
      * the minimum PCI device IdSel is 1.
      */
-    pci_bus = typhoon_init(machine->ram, &isa_bus, &rtc_irq, cpus,
+    pci_bus = typhoon_init(machine->ram, &isa_irq, &rtc_irq, cpus,
                            clipper_pci_map_irq, PCI_DEVFN(1, 0));
 
+    /*
+     * Init the PCI -> ISA bridge.
+     *
+     * Technically, PCI-based Alphas shipped with one of three different
+     * PCI-ISA bridges:
+     *
+     * - Intel i82378 SIO
+     * - Cypress CY82c693UB
+     * - ALI M1533
+     *
+     * (An Intel i82375 PCI-EISA bridge was also used on some models.)
+     *
+     * For simplicity, we model an i82378 here, even though it wouldn't
+     * have been on any Tsunami/Typhoon systems; it's close enough, and
+     * we don't want to deal with modelling the CY82c693UB (which has
+     * incompatible edge/level control registers, plus other peripherals
+     * like IDE and USB) or the M1533 (which also has IDE and USB).
+     *
+     * Importantly, we need to provide a PCI device node for it, otherwise
+     * some operating systems won't notice there's an ISA bus to configure.
+     */
+    i82378_dev = DEVICE(pci_create_simple(pci_bus, PCI_DEVFN(7, 0), "i82378"));
+    isa_bus = ISA_BUS(qdev_get_child_bus(i82378_dev, "isa.0"));
+
+    /* Connect the ISA PIC to the Typhoon IRQ used for ISA interrupts. */
+    qdev_connect_gpio_out(i82378_dev, 0, isa_irq);
+
     /* Since we have an SRM-compatible PALcode, use the SRM epoch.  */
     mc146818_rtc_init(isa_bus, 1900, rtc_irq);
 
-    i8254_pit_init(isa_bus, 0x40, 0, NULL);
-
     /* VGA setup.  Don't bother loading the bios.  */
     pci_vga_init(pci_bus);
 
@@ -106,9 +131,6 @@ static void clipper_init(MachineState *machine)
         pci_nic_init_nofail(&nd_table[i], pci_bus, "e1000", NULL);
     }
 
-    /* 2 82C37 (dma) */
-    isa_create_simple(isa_bus, "i82374");
-
     /* Super I/O */
     isa_create_simple(isa_bus, TYPE_SMC37C669_SUPERIO);
 

hw/alpha/typhoon.c

@@ -814,9 +814,9 @@ static void typhoon_alarm_timer(void *opaque)
     cpu_interrupt(CPU(s->cchip.cpu[cpu]), CPU_INTERRUPT_TIMER);
 }
 
-PCIBus *typhoon_init(MemoryRegion *ram, ISABus **isa_bus, qemu_irq *p_rtc_irq,
+PCIBus *typhoon_init(MemoryRegion *ram, qemu_irq *p_isa_irq,
-                     AlphaCPU *cpus[4], pci_map_irq_fn sys_map_irq,
+                     qemu_irq *p_rtc_irq, AlphaCPU *cpus[4],
-                     uint8_t devfn_min)
+                     pci_map_irq_fn sys_map_irq, uint8_t devfn_min)
 {
     MemoryRegion *addr_space = get_system_memory();
     DeviceState *dev;
@@ -844,6 +844,7 @@ PCIBus *typhoon_init(MemoryRegion *ram, ISABus **isa_bus, qemu_irq *p_rtc_irq,
         }
     }
 
+    *p_isa_irq = qemu_allocate_irq(typhoon_set_isa_irq, s, 0);
     *p_rtc_irq = qemu_allocate_irq(typhoon_set_timer_irq, s, 0);
 
     /* Main memory region, 0x00.0000.0000.  Real hardware supports 32GB,
@@ -919,18 +920,6 @@ PCIBus *typhoon_init(MemoryRegion *ram, ISABus **isa_bus, qemu_irq *p_rtc_irq,
     /* Pchip1 PCI I/O, 0x802.FC00.0000, 32MB.  */
     /* Pchip1 PCI configuration, 0x802.FE00.0000, 16MB.  */
 
-    /* Init the ISA bus.  */
-    /* ??? Technically there should be a cy82c693ub pci-isa bridge.  */
-    {
-        qemu_irq *isa_irqs;
-
-        *isa_bus = isa_bus_new(NULL, get_system_memory(), &s->pchip.reg_io,
-                               &error_abort);
-        isa_irqs = i8259_init(*isa_bus,
-                              qemu_allocate_irq(typhoon_set_isa_irq, s, 0));
-        isa_bus_irqs(*isa_bus, isa_irqs);
-    }
-
     return b;
 }