platform-bus were using machine_done notifier to get and map
(assign irq/mmio resources) dynamically added sysbus devices
after all '-device' options had been processed.
That however creates non obvious dependencies on ordering of
machine_done notifiers and requires carefull line juggling
to keep it working. For example see comment above
create_platform_bus() and 'straitforward' arm_load_kernel()
had to converted to machine_done notifier and that lead to
yet another machine_done notifier to keep it working
arm_register_platform_bus_fdt_creator().
Instead of hiding resource assignment in platform-bus-device
to magically initialize sysbus devices, use device plug
callback and assign resources explicitly at board level
at the moment each -device option is being processed.
That adds a bunch of machine declaration boiler plate to
e500plat board, similar to ARM/x86 but gets rid of hidden
machine_done notifier and would allow to remove the dependent
notifiers in ARM code simplifying it and making code flow
easier to follow.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-id: 1525691524-32265-3-git-send-email-imammedo@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
We need to support spawning of sysbus devices dynamically via the command line.
The easiest way to represent these dynamically spawned devices in the guest's
memory and IRQ layout is by preallocating some space for dynamic sysbus devices.
This is what the "platform bus" device does. It is a sysbus device that exports
a configurably sized MMIO region and a configurable number of IRQ lines. When
this device encounters sysbus devices that have been dynamically created and not
manually wired up, it dynamically connects them to its own pool of resources.
The machine model can then loop through all of these devices and create a guest
configuration (device tree) to make them visible to the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
Igor Mammedov