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Commit 44a9a36f authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI: Add pci_find_next_ext_capability() 



Some extended capabilities, e.g., the vendor-specific capability, can
occur several times.  The existing pci_find_ext_capability() only finds
the first occurrence.  This adds pci_find_next_ext_capability(), which
can iterate through all of them.

Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 0d7614f0

drivers/pci/pci.c

+30 −10
Original line number Diff line number Diff line
@@ -286,20 +286,17 @@ static int pci_pcie_cap2(struct pci_dev *dev) 
}



/**

 * pci_find_ext_capability - Find an extended capability

 * pci_find_next_ext_capability - Find an extended capability

 * @dev: PCI device to query

 * @start: address at which to start looking (0 to start at beginning of list)

 * @cap: capability code

 *

 * Returns the address of the requested extended capability structure

 * Returns the address of the next matching extended capability structure

 * within the device's PCI configuration space or 0 if the device does

 * not support it.  Possible values for @cap:

 *

 *  %PCI_EXT_CAP_ID_ERR		Advanced Error Reporting

 *  %PCI_EXT_CAP_ID_VC		Virtual Channel

 *  %PCI_EXT_CAP_ID_DSN		Device Serial Number

 *  %PCI_EXT_CAP_ID_PWR		Power Budgeting

 * not support it.  Some capabilities can occur several times, e.g., the

 * vendor-specific capability, and this provides a way to find them all.

 */

int pci_find_ext_capability(struct pci_dev *dev, int cap)

int pci_find_next_ext_capability(struct pci_dev *dev, int start, int cap)

{

	u32 header;

	int ttl;
@@ -311,6 +308,9 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) 
	if (dev->cfg_size <= PCI_CFG_SPACE_SIZE)

		return 0;



	if (start)

		pos = start;



	if (pci_read_config_dword(dev, pos, &header) != PCIBIOS_SUCCESSFUL)

		return 0;
@@ -322,7 +322,7 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) 
		return 0;



	while (ttl-- > 0) {

		if (PCI_EXT_CAP_ID(header) == cap)

		if (PCI_EXT_CAP_ID(header) == cap && pos != start)

			return pos;



		pos = PCI_EXT_CAP_NEXT(header);
@@ -335,6 +335,26 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) 


	return 0;

}

EXPORT_SYMBOL_GPL(pci_find_next_ext_capability);



/**

 * pci_find_ext_capability - Find an extended capability

 * @dev: PCI device to query

 * @cap: capability code

 *

 * Returns the address of the requested extended capability structure

 * within the device's PCI configuration space or 0 if the device does

 * not support it.  Possible values for @cap:

 *

 *  %PCI_EXT_CAP_ID_ERR		Advanced Error Reporting

 *  %PCI_EXT_CAP_ID_VC		Virtual Channel

 *  %PCI_EXT_CAP_ID_DSN		Device Serial Number

 *  %PCI_EXT_CAP_ID_PWR		Power Budgeting

 */

int pci_find_ext_capability(struct pci_dev *dev, int cap)

{

	return pci_find_next_ext_capability(dev, 0, cap);

}

EXPORT_SYMBOL_GPL(pci_find_ext_capability);



static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -755,6 +755,7 @@ 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_find_next_ext_capability(struct pci_dev *dev, int pos, 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);