Currently we retrieve the PCI domain number of the host bridge from the
bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually
we have the information at PCI host bridge probing time, and it makes
sense that we store it into pci_host_bridge. One benefit of doing so is
the requirement for supporting PCI on Hyper-V for ARM64, because the
host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is
a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain
number from pci_config_window on ARM64 Hyper-V guest.
As the preparation for ARM64 Hyper-V PCI support, we introduce the
domain_nr in pci_host_bridge and a sentinel value to allow drivers to
set domain numbers properly at probing time. Currently
CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this
newly-introduced field.
Link: https://lore.kernel.org/r/20210726180657.142727-2-boqun.feng@gmail.com
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
bridge->native_pme = 1;
bridge->native_ltr = 1;
bridge->native_dpc = 1;
+ bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
device_initialize(&bridge->dev);
}
bus->ops = bridge->ops;
bus->number = bus->busn_res.start = bridge->busnr;
#ifdef CONFIG_PCI_DOMAINS_GENERIC
- bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+ if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET)
+ bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+ else
+ bus->domain_nr = bridge->domain_nr;
#endif
b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
return (pdev->error_state != pci_channel_io_normal);
}
+/*
+ * Currently in ACPI spec, for each PCI host bridge, PCI Segment
+ * Group number is limited to a 16-bit value, therefore (int)-1 is
+ * not a valid PCI domain number, and can be used as a sentinel
+ * value indicating ->domain_nr is not set by the driver (and
+ * CONFIG_PCI_DOMAINS_GENERIC=y archs will set it with
+ * pci_bus_find_domain_nr()).
+ */
+#define PCI_DOMAIN_NR_NOT_SET (-1)
+
struct pci_host_bridge {
struct device dev;
struct pci_bus *bus; /* Root bus */
struct pci_ops *child_ops;
void *sysdata;
int busnr;
+ int domain_nr;
struct list_head windows; /* resource_entry */
struct list_head dma_ranges; /* dma ranges resource list */
u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */