PCI_CONFIGURE_BUS(9) | Kernel Developer's Manual | PCI_CONFIGURE_BUS(9) |
pci_configure_bus
,
pci_conf_hook
,
pci_conf_interrupt
,
pciconf_resource_init
,
pciconf_resource_add
,
pciconf_resource_fini
—
#include <dev/pci/pciconf.h>
int
pci_configure_bus
(pci_chipset_tag_t
pc, struct
pciconf_resources *res,
int firstbus,
int cacheline_size);
struct pciconf_resources *
pciconf_resource_init
(void);
void
pciconf_resource_add
(struct
pciconf_resources *res,
int type,
bus_addr_t addr,
bus_size_t size);
void
pciconf_resource_fini
(struct
pciconf_resources *res);
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
res argument is a container for PCI bus resources that
will be used to configure the bus. 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_IO
PCI_CONF_MAP_MEM
PCI_CONF_MAP_ROM
PCI_CONF_ENABLE_IO
PCI_CONF_ENABLE_MEM
PCI_CONF_ENABLE_BM
In 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).
The resources used to configure the PCI bus are encapsulated into
a resource container. The pciconf_resource_init
()
function allocates and initializes one of these containers, and the
pciconf_resource_add
() function adds resources to
the container, specifying the type, start address, and size of the resource
being added. The following resource types are supported:
PCICONF_RESOURCE_IO
PCICONF_RESOURCE_MEM
PCICONF_RESOURCE_PREFETCHABLE_MEM
If an implementation does not distinguish between prefetchable and
non-prefetchable memory, then adding a
PCICONF_RESOURCE_PREFETCHABLE_MEM
resource is not
required; PCICONF_RESOURCE_MEM
resources will be
used for ROMs and BARs that are marked as prefetchable.
Once the bus has been successfully configured, the resource
container should be disposed of by calling
pciconf_resource_fini
().
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); } }
This configuration example is taken from the bebox port.
#define PCI_IO_START 0x00008000 #define PCI_IO_END 0x0000ffff #define PCI_IO_SIZE ((PCI_IO_END - PCI_IO_START) + 1) #define PCI_MEM_START 0x00000000 #define PCI_MEM_END 0x0fffffff #define PCI_MEM_SIZE ((PCI_MEM_END - PCI_MEM_START) + 1) ... struct pciconf_resources *pcires; ... pcires = pciconf_resource_init(); pciconf_resource_add(pcires, PCICONF_RESOURCE_IO, PCI_IO_START, PCI_IO_SIZE); pciconf_resource_add(pcires, PCICONF_RESOURCE_MEM, PCI_MEM_START, PCI_MEM_SIZE); ... pci_configure_bus(pc, pcires, 0, CACHELINESIZE); ... pciconf_resource_fini(pcires); ...
Note that this must be called before the PCI bus is attached during autoconfiguration.
pci_configure_bus
() was added in NetBSD
1.6.
July 7, 2020 | NetBSD 10.1 |