On 7/18/23 11:15, Rob Herring wrote:
On Fri, Jun 30, 2023 at 12:25 PM Lizhi Hou <lizhi.hou@xxxxxxx> wrote:
On 6/29/23 16:52, Rob Herring wrote:
+ rp[i].child_addr[0] = j;
+ ret = of_changeset_add_empty_prop(ocs, np, "dynamic");
It seems slightly confusing to use a "dynamic" property here when we
also have the OF_DYNAMIC dynamic flag above. I think they have
different meanings, don't they?
Hum, what's the property for? It's new in this version. Any DT property
needs to be documented, but I don't see why we need it.
This is mentioned in my previous reply for V9
https://lore.kernel.org/lkml/af9b6bb3-a98d-4fb6-b51e-b48bca61dada@xxxxxxx/
As we discussed before, "interrupt-map" was intended to be used here.
And after thinking it more, it may not work for the cases where ppnode
is not dynamically generated and it does not have "interrupt-map".
For example the IBM ppc system, its device tree has nodes for pci bridge
and it does not have "interrupt-map".
How do you know? I ask because usually the only way I have visibility
there is when I break something. In traditional OpenFirmware, which
IBM PPC is, all PCI devices have a DT node because it's the firmware
telling the OS "these are the devices I discovered and this is how I
configured them".
I configured a ppc VM and added a bridge to the VM
qemu-system-ppc -L pc-bios -boot c -prom-env "boot-device=hd:,\yaboot"
-prom-env "boot-args=conf=hd:,\yaboot.conf" -M mac99 -m 1024 -hda
debian10.qcow2 -nographic -device pci-bridge,chassis_nr=1,id=pci.9
# ls /proc/device-tree/pci\@f2000000/pci1b36\,1\@f/
66mhz-capable class-code fast-back-to-back min-grant
vendor-id
assigned-addresses device-id interrupts name
bus-range devsel-speed linux,phandle reg
cache-line-size ethernet@1 max-latency revision-id
The bridge node does not have 'interrupt-map'. That is why I concerned
for using 'interrupt-map'.
To further debugging on if it really breaks anything, I added a nic
device under bridge. Even without my patch, it is failed anyway.
[ 0.086586] pci 0000:01:01.0: of_irq_parse_pci: failed with rc=-22
So I setup another power10 VM and see the 'interrupt-map' is created for
pci bridge. And the nic device under bridge works fine.
Maybe using 'interrupt-map' will not break anything in the real world.
I will re-create a patchset which uses 'interrupt-map' (like V9) and
checks it only when CONFIG_PCI_DYNAMIC_OF_NODES is turned on.
Thanks,
Lizhi
Based on previous discussions, OF_DYNAMIC should not be used here.
For the same reasons, I don't think the behavior should change based
on being dynamic. Now maybe the behavior when it's an ACPI system with
DT overlays has to change, but that's a problem for later. I don't yet
know if we'd handle that here somehow or elsewhere so that this node
looks like a normal DT system.
This should all work the same whether we've generated the nodes or
they were already present in the FDT when we booted.
So I think adding "dynamic" might be a way to identify the dynamically
added node. Or we can introduce a new flag e.g OF_IRQ_SWIZZLING.
I hope not. The flags tend to be hacks.
Rob
