| Message ID | 20210726180657.142727-3-boqun.feng@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: hv: Support host bridge probing on ARM64 | expand |
On Tue, Jul 27, 2021 at 02:06:51AM +0800, Boqun Feng wrote: > Currently, at probing time, the MSI domains of root buses are populated > if either the information of MSI domain is available from firmware (DT > or ACPI), or arch-specific sysdata is used to pass the fwnode of the MSI > domain. These two conditions don't cover all, e.g. Hyper-V virtual PCI > on ARM64, which doesn't have the MSI information in the firmware and > couldn't use arch-specific sysdata because running on an architecture > with PCI_DOMAINS_GENERIC=y. > > To support populating MSI domains of the root buses at the probing when > neither of the above condition is true, the ->msi_domain of the > corresponding bridge device is used: in pci_host_bridge_msi_domain(), > which should return the MSI domain of the root bus, the ->msi_domain of > the corresponding bridge is fetched first as a potential value of the > MSI domain of the root bus. > > In order to use the approach to populate MSI domains, the driver needs > to dev_set_msi_domain() on the bridge before calling > pci_register_host_bridge(), and makes sure GENERIC_MSI_IRQ_DOMAIN=y. > > Another advantage of this new approach is providing an arch-independent > way to populate MSI domains, which allows sharing the driver code as > much as possible between architectures. > > Originally-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> > --- > drivers/pci/probe.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 60c50d4f156f..ea7f2a57e2f5 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -829,11 +829,15 @@ static struct irq_domain *pci_host_bridge_msi_domain(struct pci_bus *bus) > { > struct irq_domain *d; > > + /* If the host bridge driver sets a MSI domain of the bridge, use it */ > + d = dev_get_msi_domain(bus->bridge); > + > /* > * Any firmware interface that can resolve the msi_domain > * should be called from here. > */ > - d = pci_host_bridge_of_msi_domain(bus); > + if (!d) > + d = pci_host_bridge_of_msi_domain(bus); > if (!d) > d = pci_host_bridge_acpi_msi_domain(bus); > > -- > 2.32.0 >
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 60c50d4f156f..ea7f2a57e2f5 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -829,11 +829,15 @@ static struct irq_domain *pci_host_bridge_msi_domain(struct pci_bus *bus) { struct irq_domain *d; + /* If the host bridge driver sets a MSI domain of the bridge, use it */ + d = dev_get_msi_domain(bus->bridge); + /* * Any firmware interface that can resolve the msi_domain * should be called from here. */ - d = pci_host_bridge_of_msi_domain(bus); + if (!d) + d = pci_host_bridge_of_msi_domain(bus); if (!d) d = pci_host_bridge_acpi_msi_domain(bus);
Currently, at probing time, the MSI domains of root buses are populated if either the information of MSI domain is available from firmware (DT or ACPI), or arch-specific sysdata is used to pass the fwnode of the MSI domain. These two conditions don't cover all, e.g. Hyper-V virtual PCI on ARM64, which doesn't have the MSI information in the firmware and couldn't use arch-specific sysdata because running on an architecture with PCI_DOMAINS_GENERIC=y. To support populating MSI domains of the root buses at the probing when neither of the above condition is true, the ->msi_domain of the corresponding bridge device is used: in pci_host_bridge_msi_domain(), which should return the MSI domain of the root bus, the ->msi_domain of the corresponding bridge is fetched first as a potential value of the MSI domain of the root bus. In order to use the approach to populate MSI domains, the driver needs to dev_set_msi_domain() on the bridge before calling pci_register_host_bridge(), and makes sure GENERIC_MSI_IRQ_DOMAIN=y. Another advantage of this new approach is providing an arch-independent way to populate MSI domains, which allows sharing the driver code as much as possible between architectures. Originally-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> --- drivers/pci/probe.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)