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/pci.h b/include/linux/pci.h
index a494e5d..150da2d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1285,10 +1285,12 @@
*/
#ifdef CONFIG_PCI_DOMAINS
extern int pci_domains_supported;
+int pci_get_new_domain_nr(void);
#else
enum { pci_domains_supported = 0 };
static inline int pci_domain_nr(struct pci_bus *bus) { return 0; }
static inline int pci_proc_domain(struct pci_bus *bus) { return 0; }
+static inline int pci_get_new_domain_nr(void) { return -ENOSYS; }
#endif /* CONFIG_PCI_DOMAINS */
/*
@@ -1417,6 +1419,7 @@
static inline int pci_domain_nr(struct pci_bus *bus) { return 0; }
static inline struct pci_dev *pci_dev_get(struct pci_dev *dev) { return NULL; }
+static inline int pci_get_new_domain_nr(void) { return -ENOSYS; }
#define dev_is_pci(d) (false)
#define dev_is_pf(d) (false)