of/pci: Add pci_get_new_domain_nr() and of_get_pci_domain_nr()
Add pci_get_new_domain_nr() to allocate a new domain number and
of_get_pci_domain_nr() to retrieve the PCI domain number of a given device
from DT. Host bridge drivers or architecture-specific code can choose to
implement their PCI domain number policy using these two functions.
Using of_get_pci_domain_nr() guarantees a stable PCI domain number on every
boot provided that all host bridge controllers are assigned a number in the
device tree using "linux,pci-domain" property. Mixing use of
pci_get_new_domain_nr() and of_get_pci_domain_nr() is not recommended as it
can lead to potentially conflicting domain numbers being assigned to root
buses behind different host bridges.
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index dde3a4a..71062e9 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -15,6 +15,7 @@
int of_pci_get_devfn(struct device_node *np);
int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
+int of_get_pci_domain_nr(struct device_node *node);
#else
static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
@@ -43,6 +44,12 @@
{
return -EINVAL;
}
+
+static inline int
+of_get_pci_domain_nr(struct device_node *node)
+{
+ return -1;
+}
#endif
#if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)