[RFC PATCH 09/10] hw/isa: Resolve unneeded usage of isabus global

[Bernhard Beschow <shentey@gmail.com>]

Now that all call sites of these functions are fixed to pass non-NULL
ISADevices, the ISABus can be determined from the ISADevice argument.

Patch based on https://lists.nongnu.org/archive/html/qemu-devel/2021-05/
msg05785.html.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 hw/ide/ioport.c      |  4 ++--
 hw/isa/isa-bus.c     | 21 +++++++++++++--------
 include/hw/isa/isa.h |  2 +-
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/hw/ide/ioport.c b/hw/ide/ioport.c
index 69e4fa15d4..112726e415 100644
--- a/hw/ide/ioport.c
+++ b/hw/ide/ioport.c
@@ -53,8 +53,8 @@ static const MemoryRegionPortio ide_portio2_list[] = {
 
 void isa_ide_init_ioport(IDEBus *bus, ISADevice *dev, int iobase, int iobase2)
 {
-    /* ??? Assume only ISA and PCI configurations, and that the PCI-ISA
-       bridge has been setup properly to always register with ISA.  */
+    assert(dev);
+
     isa_register_portio_list(dev, &bus->portio_list,
                              iobase, ide_portio_list, bus, "ide");
 
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 9e8b5da027..5518db93cd 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -116,6 +116,10 @@ static inline void isa_init_ioport(ISADevice *dev, uint16_t ioport)
 
 void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start)
 {
+    ISABus *isabus;
+
+    assert(dev);
+    isabus = isa_bus_from_device(dev);
     memory_region_add_subregion(isabus->address_space_io, start, io);
     isa_init_ioport(dev, start);
 }
@@ -125,8 +129,13 @@ void isa_register_portio_list(ISADevice *dev,
                               const MemoryRegionPortio *pio_start,
                               void *opaque, const char *name)
 {
+    ISABus *isabus;
+
+    assert(dev);
     assert(piolist && !piolist->owner);
 
+    isabus = isa_bus_from_device(dev);
+
     /* START is how we should treat DEV, regardless of the actual
        contents of the portio array.  This is how the old code
        actually handled e.g. the FDC device.  */
@@ -246,20 +255,16 @@ static char *isabus_get_fw_dev_path(DeviceState *dev)
 
 MemoryRegion *isa_address_space(ISADevice *dev)
 {
-    if (dev) {
-        return isa_bus_from_device(dev)->address_space;
-    }
+    assert(dev);
 
-    return isabus->address_space;
+    return isa_bus_from_device(dev)->address_space;
 }
 
 MemoryRegion *isa_address_space_io(ISADevice *dev)
 {
-    if (dev) {
-        return isa_bus_from_device(dev)->address_space_io;
-    }
+    assert(dev);
 
-    return isabus->address_space_io;
+    return isa_bus_from_device(dev)->address_space_io;
 }
 
 type_init(isabus_register_types)
diff --git a/include/hw/isa/isa.h b/include/hw/isa/isa.h
index 8dd2953211..486851e7cb 100644
--- a/include/hw/isa/isa.h
+++ b/include/hw/isa/isa.h
@@ -108,7 +108,7 @@ void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start);
  * function makes it easy to create multiple MemoryRegions for a single
  * device and use the legacy portio routines.
  *
- * @dev: the ISADevice against which these are registered; may be NULL.
+ * @dev: the ISADevice against which these are registered
  * @piolist: the PortioList associated with the io ports
  * @start: the base I/O port against which the portio->offset is applied.
  * @portio: the ports, sorted by offset.
-- 
2.36.1