From 41e5c0f81d3e676d671d96a0a1fafb27abfbd9d7 Mon Sep 17 00:00:00 2001 From: Liviu Dudau Date: Mon, 29 Sep 2014 15:29:27 +0100 Subject: 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 Signed-off-by: Bjorn Helgaas CC: Arnd Bergmann CC: Grant Likely CC: Rob Herring CC: Catalin Marinas --- drivers/of/of_pci.c | 25 +++++++++++++++++++++++++ drivers/pci/pci.c | 9 +++++++++ 2 files changed, 34 insertions(+) (limited to 'drivers') diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c index 848199633798..82d172fa145a 100644 --- a/drivers/of/of_pci.c +++ b/drivers/of/of_pci.c @@ -89,6 +89,31 @@ int of_pci_parse_bus_range(struct device_node *node, struct resource *res) } EXPORT_SYMBOL_GPL(of_pci_parse_bus_range); +/** + * This function will try to obtain the host bridge domain number by + * finding a property called "linux,pci-domain" of the given device node. + * + * @node: device tree node with the domain information + * + * Returns the associated domain number from DT in the range [0-0xffff], or + * a negative value if the required property is not found. + */ +int of_get_pci_domain_nr(struct device_node *node) +{ + const __be32 *value; + int len; + u16 domain; + + value = of_get_property(node, "linux,pci-domain", &len); + if (!value || len < sizeof(*value)) + return -EINVAL; + + domain = (u16)be32_to_cpup(value); + + return domain; +} +EXPORT_SYMBOL_GPL(of_get_pci_domain_nr); + #ifdef CONFIG_PCI_MSI static LIST_HEAD(of_pci_msi_chip_list); diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2c9ac70254e2..d36f35ff6c5d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4406,6 +4406,15 @@ static void pci_no_domains(void) #endif } +#ifdef CONFIG_PCI_DOMAINS +static atomic_t __domain_nr = ATOMIC_INIT(-1); + +int pci_get_new_domain_nr(void) +{ + return atomic_inc_return(&__domain_nr); +} +#endif + /** * pci_ext_cfg_avail - can we access extended PCI config space? * -- cgit v1.2.3