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of/pci: Add pci_get_new_domain_nr() and of_get_pci_domain_nr()

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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>
This commit is contained in:
Liviu Dudau 2014-09-29 15:29:27 +01:00 committed by Bjorn Helgaas
parent 670ba0c888
commit 41e5c0f81d
4 changed files with 44 additions and 0 deletions
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25
drivers/of/of_pci.c
View File

@ -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);

9
drivers/pci/pci.c
View File

@ -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?
*

7
include/linux/of_pci.h
View File

@ -15,6 +15,7 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
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 @@ of_pci_parse_bus_range(struct device_node *node, struct resource *res)
{
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)

3
include/linux/pci.h
View File

@ -1285,10 +1285,12 @@ void pci_cfg_access_unlock(struct pci_dev *dev);
*/
#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 struct pci_dev *pci_get_bus_and_slot(unsigned int bus,
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)