pcibios_find_class

Section: BIOS32 Functions (9)
Updated: August 5, 1997
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NAME

pcibios_find_class, pcibios_find_device - find a PCI class or device

SYNOPSIS

#include <linux/bios32.h>

int pcibios_find_class(unsigned int class_code, unsigned short index, unsigned char* bus, unsigned char* device_fn);
int pcibios_find_device(unsigned short vendor, unsigned short device_id , unsigned short index, unsigned char* bus, unsigned char* device_fn);

DESCRIPTION

The pcibios_find_class function searches for a certain class of device on the PCI bus. In this instance, class is used to represent a few different categories of devices. Some examples are storage, network, display, and memory classes. The classes are defined by the PCI Specification, and the class_code is matched with the dword in the configuration space of the device at offset 0x08.

The pcibios_find_device function finds a device on the PCI bus that has the matching device and vendor ids. The vendor ids are assigned to the PCI Sig to vendors, who in turn assign device ids to the devices they develop. The vendor and device ids are encoded in dword 0x00 of the configuration space.

Both pcibios_find_class and pcibios_find_device include an extra index parameter, which is used to select the specific device if there are multiple matches. An index of 0 matches the firts located board, 1 the second, and so on.

The bus and device_fn parameters are PCI specific cookies that are passed to other pcibios functions to access the configuration space of the located device.

RETURN VALUE

On success, the functions return PCIBIOS_SUCCESSFUL. Otherwise, one of the following error codes is returned:

PCIBIOS_DEVICE_NOT_FOUND: There is no device that matches the search criteria,
PCIBIOS_BAD_VENDOR_ID: The vendor id is invalid. (0xffff is not a valid id.)
PCIBIOS_FUNC_NOT_SUPPRTED: The PCI subsystem is not available

AVAILABILITY

Linux 1.0+

AUTHOR

Kirk Petersen (kirk@speakeasy.org)