| PCI_CONFIGURE_BUS(9) | Kernel Developer's Manual | PCI_CONFIGURE_BUS(9) | 
pci_configure_bus,
  pci_conf_hook,
  pci_conf_interrupt —
#include <dev/pci/pciconf.h>
int
  
  pci_configure_bus(pci_chipset_tag_t
    pc, struct extent *ioext, struct
    extent *memext, struct extent *pmemext,
    int firstbus, int
    cacheline_size);
pci_configure_bus() function configures a PCI bus
  for use. This involves:
In traditional PCs and Alpha systems, the BIOS or firmware takes
    care of this task, but that is not the case for all systems.
    pci_configure_bus() should be called prior to the
    autoconfiguration of the bus.
The pc argument is a machine-dependent tag
    used to specify the PCI chipset to the system. This should be the same value
    used with pci_make_tag(). The extent arguments
    define memory extents from which the address space for the cards will be
    taken. These addresses should be in the PCI address space. The
    ioext extent is for PCI I/O accesses. The
    memext extent is for PCI memory accesses that might
    have side effects. I.e., that can not be cached. The
    pmemext extent is for PCI memory accesses that can be
    cached. The pmemext extent will be used for any ROMs
    and any memory regions that are marked as “prefetchable” in
    their BAR. If an implementation does not distinguish between prefetchable
    and non-prefetchable memory, it may pass NULL for
    pmemext. In this case, prefetchable memory allocations
    will be made from the non-prefetchable region. The
    firstbus argument indicates the number of the first
    bus to be configured. The cacheline_size argument is
    used to configure the PCI Cache Line Size Register; it should be the size,
    in bytes, of the largest D-cache line on the system.
An implementation may choose to not have full configuration
    performed by pci_configure_bus() on certain PCI
    devices, such as PCI host bridges or PCI bus analyzers which are
    instantiated as devices on the bus. In order for this to take place, the
    header
    <machine/pci_machdep.h> must
    define the __HAVE_PCI_CONF_HOOK symbol (without a
    value), and a machine-dependent function
    pci_conf_hook() (declared in the same header) must
    be defined. The prototype for this function is
int
    pci_conf_hook(pci_chipset_tag_t
    pc, int bus, int device,
    int function, pcireg_t id)
In this function, bus,
    device, and function uniquely
    identify the item being configured; in addition to this, the value of the
    device's PCI identification register is passed in id.
    For each device pci_conf_hook() can then decide upon
    the amount of configuration to be performed by returning a bitwise
    inclusive-or of the following flags:
PCI_CONF_MAP_IOPCI_CONF_MAP_MEMPCI_CONF_MAP_ROMPCI_CONF_ENABLE_IOPCI_CONF_ENABLE_MEMPCI_CONF_ENABLE_BMIn addition, PCI_CONF_ALL specifies all of
    the above.
One of the functions of
    pci_configure_bus() is to configure interrupt
    “line” information. This must be done on a machine-dependent
    basis, so a machine-dependent function
    pci_conf_interrupt() must be defined. The prototype
    for this function is
void
    pci_conf_interrupt(pci_chipset_tag_t
    pc, int bus, int device,
    int pin, int swiz,
    int *iline)
In this function, bus, device, and pin, uniquely identify the item being configured. The swiz argument is a “swizzle”, a sum of the device numbers of the primary interface of the bridges between the host bridge and the current device. The function is responsible for setting the value of iline. See chapter 9 of the “PCI-to-PCI Bridge Architecture Specification” for more information on swizzling (also known as interrupt routing).
pci_configure_bus() returns 0. A non-zero
  return value means that the bus was not completely configured for some reason.
  A description of the failure will be displayed on the console.
pci_configure_bus() function is only included in the
  kernel if the kernel is compiled with the
  PCI_NETBSD_CONFIGURE option enabled.
pci_conf_hook() function in evbppc's walnut
  implementation looks like:
int
pci_conf_hook(pci_chipset_tag_t pc, int bus, int dev, int func,
    pcireg_t id)
{
	if ((PCI_VENDOR(id) == PCI_VENDOR_IBM &&
	     PCI_PRODUCT(id) == PCI_PRODUCT_IBM_405GP) ||
	    (PCI_VENDOR(id) == PCI_VENDOR_INTEL &&
	     PCI_PRODUCT(id) == PCI_PRODUCT_INTEL_80960_RP)) {
		/* Don't configure the bridge and PCI probe. */
		return 0;
	}
	return (PCI_CONF_ALL & ~PCI_CONF_MAP_ROM);
}
The pci_conf_interrupt() function in the
    sandpoint implementation looks like:
void
pci_conf_interrupt(pci_chipset_tag_t pc, int bus, int dev, int pin,
    int swiz, int *iline)
{
	if (bus == 0) {
		*iline = dev;
	} else {
		*iline = 13 + ((swiz + dev + 3) & 3);
	}
}
The BeBox has nearly 1GB of PCI I/O memory starting at processor
    address 0x81000000 (PCI I/O address 0x01000000), and nearly 1GB of PCI
    memory starting at 0xC0000000 (PCI memory address 0x00000000). The
    pci_configure_bus() function might be called as
    follows:
	struct extent *ioext, *memext;
	...
	ioext  = extent_create("pciio",  0x01000000, 0x0fffffff,
	    NULL, 0, EX_NOWAIT);
	memext = extent_create("pcimem", 0x00000000, 0x0fffffff,
	    NULL, 0, EX_NOWAIT);
	...
	pci_configure_bus(0, ioext, memext, NULL);
	...
	extent_destroy(ioext);
	extent_destroy(memext);
	...
Note that this must be called before the PCI bus is attached during autoconfiguration.
pci_configure_bus() was added in NetBSD
  1.6.
| February 21, 2006 | NetBSD 9.3 |