Commit 24a4e377 authored by Roland Dreier's avatar Roland Dreier Committed by Greg Kroah-Hartman
Browse files

[PATCH] PCI: add pci_find_next_capability() 



Some devices have more than one capability of the same type.  For
example, the PCI header for the PathScale InfiniPath looks like:

	04:01.0 InfiniBand: Unknown device 1fc1:000d (rev 02)
		Subsystem: Unknown device 1fc1:000d
		Flags: bus master, fast devsel, latency 0, IRQ 193
		Memory at fea00000 (64-bit, non-prefetchable) [size=2M]
		Capabilities: [c0] HyperTransport: Slave or Primary Interface
		Capabilities: [f8] HyperTransport: Interrupt Discovery and Configuration

There are _two_ HyperTransport capabilities, and the PathScale driver
wants to look at both of them.

The current pci_find_capability() API doesn't work for this, since it
only allows us to get to the first capability of a given type.  The
patch below introduces a new pci_find_next_capability(), which can be
used in a loop like

	for (pos = pci_find_capability(pdev, <ID>);
	     pos;
	     pos = pci_find_next_capability(pdev, pos, <ID>)) {
		/* ... */
	}

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
Signed-off-by: default avatarMatthew Wilcox <matthew@wil.cx>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6d23c8bc

drivers/pci/pci.c

+32 −14
Original line number Diff line number Diff line
@@ -63,11 +63,38 @@ pci_max_busnr(void) 
	return max;

}



static int __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn, u8 pos, int cap)

{

	u8 id;

	int ttl = 48;



	while (ttl--) {

		pci_bus_read_config_byte(bus, devfn, pos, &pos);

		if (pos < 0x40)

			break;

		pos &= ~3;

		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID,

					 &id);

		if (id == 0xff)

			break;

		if (id == cap)

			return pos;

		pos += PCI_CAP_LIST_NEXT;

	}

	return 0;

}



int pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)

{

	return __pci_find_next_cap(dev->bus, dev->devfn,

				   pos + PCI_CAP_LIST_NEXT, cap);

}

EXPORT_SYMBOL_GPL(pci_find_next_capability);



static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_type, int cap)

{

	u16 status;

	u8 pos, id;

	int ttl = 48;

	u8 pos;



	pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);

	if (!(status & PCI_STATUS_CAP_LIST))
@@ -76,24 +103,15 @@ static int __pci_bus_find_cap(struct pci_bus *bus, unsigned int devfn, u8 hdr_ty 
	switch (hdr_type) {

	case PCI_HEADER_TYPE_NORMAL:

	case PCI_HEADER_TYPE_BRIDGE:

		pci_bus_read_config_byte(bus, devfn, PCI_CAPABILITY_LIST, &pos);

		pos = PCI_CAPABILITY_LIST;

		break;

	case PCI_HEADER_TYPE_CARDBUS:

		pci_bus_read_config_byte(bus, devfn, PCI_CB_CAPABILITY_LIST, &pos);

		pos = PCI_CB_CAPABILITY_LIST;

		break;

	default:

		return 0;

	}

	while (ttl-- && pos >= 0x40) {

		pos &= ~3;

		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_ID, &id);

		if (id == 0xff)

			break;

		if (id == cap)

			return pos;

		pci_bus_read_config_byte(bus, devfn, pos + PCI_CAP_LIST_NEXT, &pos);

	}

	return 0;

	return __pci_find_next_cap(bus, devfn, pos, cap);

}



/**

include/linux/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -338,6 +338,7 @@ struct pci_dev *pci_find_device (unsigned int vendor, unsigned int device, const 
struct pci_dev *pci_find_device_reverse (unsigned int vendor, unsigned int device, const struct pci_dev *from);

struct pci_dev *pci_find_slot (unsigned int bus, unsigned int devfn);

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);

struct pci_bus * pci_find_next_bus(const struct pci_bus *from);
@@ -550,6 +551,7 @@ static inline int pci_assign_resource(struct pci_dev *dev, int i) { return -EBUS 
static inline int pci_register_driver(struct pci_driver *drv) { return 0;}

static inline void pci_unregister_driver(struct pci_driver *drv) { }

static inline int pci_find_capability (struct pci_dev *dev, int cap) {return 0; }

static inline int pci_find_next_capability (struct pci_dev *dev, u8 post, int cap) { return 0; }

static inline int pci_find_ext_capability (struct pci_dev *dev, int cap) {return 0; }

static inline const struct pci_device_id *pci_match_device(const struct pci_device_id *ids, const struct pci_dev *dev) { return NULL; }

CRA Git | Maintained and supported by SUSTech CRA and CCSE