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Commit 41e5c0f8 authored by Liviu Dudau's avatar Liviu Dudau Committed by Bjorn Helgaas
Browse files

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: default avatarLiviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: default avatarBjorn 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>
parent 670ba0c8

drivers/of/of_pci.c

+25 −0
Original line number Diff line number Diff line
@@ -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);

drivers/pci/pci.c

+9 −0
Original line number Diff line number Diff line
@@ -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?

 *

include/linux/of_pci.h

+7 −0
Original line number Diff line number Diff line
@@ -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)

include/linux/pci.h

+3 −0
Original line number Diff line number Diff line
@@ -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)