text: pci_find_class()
  Find devices that have a specific class code
  Synopsis:
  #include <hw/pci.h> int pci_find_class( unsigned long class_code, unsigned index, unsigned* bus, unsigned* dev_func );
  Arguments:
  - class_code
  - The class of device or function that you want to find. For a list of class codes, see <hw/pci.h>. You must OR together a class code and a subclass code (e.g. PCI_CLASS_DISPLAY | PCI_SUBCLASS_DISPLAY_XGA).
  - index
  - The index of the device or function that you want to find: 0 for the first, 1 for the second, and so on.
  - bus
  - The bus number, in the range [0...255].
  - dev_func
  - The device or function number of the nth device or function of the given class. The device number is in bits 7 through 3, and the function number in bits 2 through 0.
  Library:
  libc
  Use the -l c option to qcc to link against this library. This library is usually included automatically.
  Description:
  The pci_find_class() function determines the location of the nth PCI device or function that has the specified class code.
  You must successfully call pci_attach() before calling any of the other PCI functions.
  You can find all the devices having the same class.