Commit cf4c43dd authored by Jesse Barnes's avatar Jesse Barnes Committed by H. Peter Anvin
Browse files

PCI: Add pci_bus_find_ext_capability 



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

Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFD@orsmsx508.amr.corp.intel.com>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 724e6d3f

drivers/pci/pci.c

+43 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

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