sysbus: Add dynamic sysbus device search

Sysbus devices can be spawned by C code or dynamically via the command line.
In the latter case, we need to be able to find the dynamically created devices
to do things with them.

This patch adds a search helper that makes it easy to look for dynamically
spawned sysbus devices.

Signed-off-by: Alexander Graf <agraf@suse.de>
sysbus: Make devices spawnable via -device

Now that we can properly map sysbus devices that haven't been connected to
something forcefully by C code, we can allow the -device command line option
to spawn them.

For machines that don't implement dynamic sysbus assignment in their board
files we add a new bool "has_dynamic_sysbus" to the machine class.
When that property is false (default), we bail out when we see dynamically
spawned sysbus devices, like we did before.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - use bool in MachineClass rather than property

v2 -> v3:

  - use search helper

v3 -> v4:

  - reword error message
sysbus: Expose IRQ enumeration helpers

Sysbus devices can get their IRQ lines connected to other devices. It is
possible to figure out which IRQ line a connection is on and whether a sysbus
device even provides an IRQ connector at a specific offset.

This patch exposes helpers to make this information publicly accessible. We
will need it for the platform bus dynamic sysbus enumeration.

Signed-off-by: Alexander Graf <agraf@suse.de>
sysbus: Expose MMIO enumeration helper

Sysbus devices have a range of MMIO regions they expose. The exact number
of regions is device specific and internal information to the device model.

Expose whether a region exists via a public interface. That way our platform
bus enumeration code can dynamically determine how many regions exist.

Signed-off-by: Alexander Graf <agraf@suse.de>
sysbus: Add new platform bus helper device

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>
PPC: e500: Support dynamically spawned sysbus devices

For e500 our approach to supporting dynamically spawned sysbus devices is to
create a simple bus from the guest's point of view within which we map those
devices dynamically.

We allocate memory regions always within the "platform" hole in address
space and map IRQs to predetermined IRQ lines that are reserved for platform
device usage.

This maps really nicely into device tree logic, so we can just tell the
guest about our virtual simple bus in device tree as well.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - access sysbus properties via qom
  - move platform bus definitions to params
  - move platform bus to 36bit address space
  - make naming more consistent
  - remove device_type from platform bus dt node
  - remove id field in dt generation

v2 -> v3:

  - use platform bus device, remove our own allocation
  - use sysbus search helper
  - add notifier for device tree regeneration
e500: Add support for eTSEC in device tree

This patch adds support to expose eTSEC devices in the dynamically created
guest facing device tree. This allows us to expose eTSEC devices into guests
without changes in the machine file.

Because we can now tell the guest about eTSEC devices this patch allows the
user to specify eTSEC devices via -device at all.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - fix device name (base on reg for value after @)
  - use qom properties to fetch mmio and irq props
  - remove useless interrupt-parent
  - make interrupts level triggered

v2 -> v3:

  - use new platform bus APIs