[Qemu-devel] [PATCH 0/9] Add platform bus

[Alexander Graf <agraf@suse.de>]

Platforms without ISA and/or PCI have had a seriously hard time in the dynamic
device creation world of QEMU. Devices on these were modeled as SysBus devices
which can only be instantiated in machine files, not through -device.

Why is that so?

Well, SysBus is trying to be incredibly generic. It allows you to plug any
interrupt sender into any other interrupt receiver. It allows you to map
a device's memory regions into any other random memory region. All of that
only works from C code.

But do we need that level of complexity for normal devices usually? In a
normal platform world (SoCs, PV machines) we have a flat memory layout we
can plug our device memory into. We also have a flat IRQ model where we
can plug our device IRQs into.

This platform bus creates a simple bus that models the easy world. It allows
for dynamic device creation through -device. A device may or may not explictly
request to be mapped at a specific IRQ and/or memory address. If no explicit
mapping is requested, platform devices just get mapped at convenient places.

This goes hand in hand with automatic device tree generation. When QEMU
places devices somewhere and also generates a device tree to tell the guest
where exactly those devices are, we close the cycle and everyone knows
everything and lives happily ever after.

The actual pressing issue this solves is that today it's impossible to spawn
serial ports from the command line. With this patch set, it's possible to
do so. But it lays the groundwork for much more...

Alex

Alexander Graf (9):
  PlatBus: Add Platform Bus
  PlatBus: Add abstract Platform Device
  PlatBus: Add Sysbus/Platform bridge device
  PlatBus: Hook up into Makefile system
  PPC: Add platform bus to the default compile set
  PlatBus: Add serial-platbus device
  PPC: Add PlatBus Serial to default configs
  PPC: E500: Spawn PlatBus bridge for ppce500 machine
  PPC: E500: Add PlatBus device tree walker

 default-configs/ppc-softmmu.mak    |   2 +
 default-configs/ppc64-softmmu.mak  |   2 +
 default-configs/ppcemb-softmmu.mak |   2 +
 hw/Makefile.objs                   |   1 +
 hw/char/Makefile.objs              |   1 +
 hw/char/serial-platbus.c           | 100 +++++++++++++++++++++++
 hw/platbus/Makefile.objs           |   1 +
 hw/platbus/bridge.c                |  64 +++++++++++++++
 hw/platbus/device.c                | 162 +++++++++++++++++++++++++++++++++++++
 hw/platbus/platbus.c               | 107 ++++++++++++++++++++++++
 hw/ppc/e500.c                      |  75 ++++++++++++++++-
 hw/ppc/e500.h                      |   1 +
 hw/ppc/e500plat.c                  |   1 +
 include/hw/char/serial-platbus.h   |  56 +++++++++++++
 include/hw/platbus/bridge.h        |  32 ++++++++
 include/hw/platbus/device.h        | 102 +++++++++++++++++++++++
 include/hw/platbus/platbus.h       |  86 ++++++++++++++++++++
 17 files changed, 791 insertions(+), 4 deletions(-)
 create mode 100644 hw/char/serial-platbus.c
 create mode 100644 hw/platbus/Makefile.objs
 create mode 100644 hw/platbus/bridge.c
 create mode 100644 hw/platbus/device.c
 create mode 100644 hw/platbus/platbus.c
 create mode 100644 include/hw/char/serial-platbus.h
 create mode 100644 include/hw/platbus/bridge.h
 create mode 100644 include/hw/platbus/device.h
 create mode 100644 include/hw/platbus/platbus.h

-- 
1.8.1.4