Many PCI host bridges consist of a sysbus device and a PCI device.
You need both for the thing to work. Arguably, these bridges should
be modelled as a single, composite devices instead of pairs of
seemingly independent devices you can only use together, but we're not
there, yet.
Since the sysbus part can't be instantiated with device_add, yet,
permitting it with the PCI part is useless. We shouldn't offer
useless options to the user, so let's set
cannot_instantiate_with_device_add_yet for them.
It's already set for Bonito, Grackle, i440FX and Raven. Document why.
Set it for the others: dec-21154, e500-host-bridge, gt64120_pci, mch,
pbm-pci, ppc4xx-host-bridge, sh_pci_host, u3-agp, uni-north-agp,
uni-north-internal-pci, uni-north-pci, and versatile_pci_host.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
device_add plugs devices into suitable bus. For "real" buses, that
actually connects the device. For sysbus, the connections need to be
made separately, and device_add can't do that. The device would be
left unconnected, and could not possibly work.
Quite a few, but not all sysbus devices already set
cannot_instantiate_with_device_add_yet in their class init function.
Set it in their abstract base's class init function
sysbus_device_class_init(), and remove the now redundant assignments
from device class init functions.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
In an ideal world, machines can be built by wiring devices together
with configuration, not code. Unfortunately, that's not the world we
live in right now. We still have quite a few devices that need to be
wired up by code. If you try to device_add such a device, it'll fail
in sometimes mysterious ways. If you're lucky, you get an
unmysterious immediate crash.
To protect users from such badness, DeviceClass member no_user used to
make device models unavailable with -device / device_add, but that
regressed in commit 18b6dad. The device model is still omitted from
help, but is available anyway.
Attempts to fix the regression have been rejected with the argument
that the purpose of no_user isn't clear, and it's prone to misuse.
This commit clarifies no_user's purpose. Anthony suggested to rename
it cannot_instantiate_with_device_add_yet_due_to_internal_bugs, which
I shorten somewhat to keep checkpatch happy. While there, make it
bool.
Every use of cannot_instantiate_with_device_add_yet gets a FIXME
comment asking for rationale. The next few commits will clean them
all up, either by providing a rationale, or by getting rid of the use.
With that done, the regression fix is hopefully acceptable.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
There's no good reason to call our bus "pci" rather than let the default
bus name take over ("pci.0").
The big downside to calling it different from anyone else is that tools
that pass -device get confused. They are looking for a bus "pci.0" rather
than "pci".
To make life easier for everyone, let's just drop the name override.
Signed-off-by: Alexander Graf <agraf@suse.de>
Markus Armbruster