On Thu, Jul 18, 2024 at 02:11:00PM +0200, Konrad Dybcio wrote:
> On 17.07.2024 7:03 PM, Manivannan Sadhasivam via B4 Relay wrote:
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> >
> > Right now, PCI endpoint subsystem doesn't assign PCI domain number for the
> > PCI endpoint controllers. But this domain number could be useful to the EPC
> > drivers to uniquely identify each controller based on the hardware instance
> > when there are multiple ones present in an SoC (even multiple RC/EP).
> >
> > So let's make use of the existing pci_bus_find_domain_nr() API to allocate
> > domain numbers based on either Devicetree (linux,pci-domain) property or
> > dynamic domain number allocation scheme.
> >
> > It should be noted that the domain number allocated by this API will be
> > based on both RC and EP controllers in a SoC. If the 'linux,pci-domain' DT
> > property is present, then the domain number represents the actual hardware
> > instance of the PCI endpoint controller. If not, then the domain number
> > will be allocated based on the PCI EP/RC controller probe order.
> >
> > If the architecture doesn't support CONFIG_PCI_DOMAINS_GENERIC (rare), then
> > currently a warning is thrown to indicate that the architecture specific
> > implementation is needed.
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > ---
> > drivers/pci/endpoint/pci-epc-core.c | 10 ++++++++++
> > include/linux/pci-epc.h | 2 ++
> > 2 files changed, 12 insertions(+)
> >
> > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> > index 84309dfe0c68..7fa81b91e762 100644
> > --- a/drivers/pci/endpoint/pci-epc-core.c
> > +++ b/drivers/pci/endpoint/pci-epc-core.c
> > @@ -838,6 +838,9 @@ void pci_epc_destroy(struct pci_epc *epc)
> > {
> > pci_ep_cfs_remove_epc_group(epc->group);
> > device_unregister(&epc->dev);
> > +
> > + if (IS_ENABLED(CONFIG_PCI_DOMAINS_GENERIC))
> > + pci_bus_release_domain_nr(NULL, &epc->dev);
>
> Shouldn't this be called before device_unregister? pci/remove.c
> does that (via pci_remove_bus() in pci_remove_root_bus())
>
No, the release should follow the allocation order in __pci_epc_create. As per
that, pci_bus_release_domain_nr() should come last.
- Mani
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