i386/pc: pc_basic_device_init(): delegate FDC creation request

This patch introduces no observable change, but it allows the callers of
pc_basic_device_init(), ie. pc_init1() and pc_q35_init(), to request (or
not request) the creation of the FDC explicitly.

At the moment both callers pass constant create_fdctrl=true (hence no
observable change).

Assuming a board passes create_fdctrl=false, "floppy" will be NULL on
output, and (beyond the FDC not being created) that NULL will be passed on
to pc_cmos_init(). Luckily, pc_cmos_init() already handles that case.

Cc: Markus Armbruster <armbru@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: John Snow <jsnow@redhat.com>
Cc: "Gabriel L. Somlo" <gsomlo@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

hw/i386/pc.c

@@ -1395,6 +1395,7 @@ static const MemoryRegionOps ioportF0_io_ops = {
 
 void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
                           ISADevice **rtc_state,
+                          bool create_fdctrl,
                           ISADevice **floppy,
                           bool no_vmport,
                           uint32 hpet_irqs)
@@ -1490,7 +1491,7 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
     for(i = 0; i < MAX_FD; i++) {
         fd[i] = drive_get(IF_FLOPPY, 0, i);
     }
-    *floppy = fdctrl_init_isa(isa_bus, fd);
+    *floppy = create_fdctrl ? fdctrl_init_isa(isa_bus, fd) : NULL;
 }
 
 void pc_nic_init(ISABus *isa_bus, PCIBus *pci_bus)

hw/i386/pc_piix.c

@@ -242,7 +242,7 @@ static void pc_init1(MachineState *machine)
     }
 
     /* init basic PC hardware */
-    pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy,
+    pc_basic_device_init(isa_bus, gsi, &rtc_state, true, &floppy,
                          (pc_machine->vmport != ON_OFF_AUTO_ON), 0x4);
 
     pc_nic_init(isa_bus, pci_bus);

hw/i386/pc_q35.c

@@ -250,7 +250,7 @@ static void pc_q35_init(MachineState *machine)
     }
 
     /* init basic PC hardware */
-    pc_basic_device_init(isa_bus, gsi, &rtc_state, &floppy,
+    pc_basic_device_init(isa_bus, gsi, &rtc_state, true, &floppy,
                          (pc_machine->vmport != ON_OFF_AUTO_ON), 0xff0104);
 
     /* connect pm stuff to lpc */

include/hw/i386/pc.h

@@ -197,6 +197,7 @@ qemu_irq *pc_allocate_cpu_irq(void);
 DeviceState *pc_vga_init(ISABus *isa_bus, PCIBus *pci_bus);
 void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
                           ISADevice **rtc_state,
+                          bool create_fdctrl,
                           ISADevice **floppy,
                           bool no_vmport,
                           uint32 hpet_irqs);