Messages in this thread Patch in this message | | | From | Boqun Feng <> | Subject | [PATCH v6 2/8] PCI: Support populating MSI domains of root buses via bridges | Date | Tue, 27 Jul 2021 02:06:51 +0800 |
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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(-)
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
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