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PCI: Add pci_bus_find_ext_capability

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For use by code that needs to walk extended capability lists before
pci_dev structures are set up.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFD@orsmsx508.amr.corp.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Jesse Barnes 2009-07-15 13:13:00 -07:00 committed by H. Peter Anvin
parent 724e6d3fe8
commit cf4c43dd43
2 changed files with 45 additions and 0 deletions
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43
drivers/pci/pci.c
View file

@ -297,6 +297,49 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap)
}
EXPORT_SYMBOL_GPL(pci_find_ext_capability);
/**
* pci_bus_find_ext_capability - find an extended capability
* @bus: the PCI bus to query
* @devfn: PCI device to query
* @cap: capability code
*
* Like pci_find_ext_capability() but works for pci devices that do not have a
* pci_dev structure set up yet.
*
* Returns the address of the requested capability structure within the
* device's PCI configuration space or 0 in case the device does not
* support it.
*/
int pci_bus_find_ext_capability(struct pci_bus *bus, unsigned int devfn,
int cap)
{
u32 header;
int ttl;
int pos = PCI_CFG_SPACE_SIZE;
/* minimum 8 bytes per capability */
ttl = (PCI_CFG_SPACE_EXP_SIZE - PCI_CFG_SPACE_SIZE) / 8;
if (!pci_bus_read_config_dword(bus, devfn, pos, &header))
return 0;
if (header == 0xffffffff || header == 0)
return 0;
while (ttl-- > 0) {
if (PCI_EXT_CAP_ID(header) == cap)
return pos;
pos = PCI_EXT_CAP_NEXT(header);
if (pos < PCI_CFG_SPACE_SIZE)
break;
if (!pci_bus_read_config_dword(bus, devfn, pos, &header))
break;
}
return 0;
}
static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
{
int rc, ttl = PCI_FIND_CAP_TTL;

2
include/linux/pci.h
View file

@ -631,6 +631,8 @@ enum pci_lost_interrupt_reason pci_lost_interrupt(struct pci_dev *dev);
int pci_find_capability(struct pci_dev *dev, int cap);
int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
int pci_find_ext_capability(struct pci_dev *dev, int cap);
int pci_bus_find_ext_capability(struct pci_bus *bus, unsigned int devfn,
int cap);
int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
struct pci_bus *pci_find_next_bus(const struct pci_bus *from);