UnixWare 7 and SCO OpenServer

pci(D5)

pci -- data format of the PCI configuration space

Synopsis

   #include <sys/pci.h>

Description

PCI configuration space is persistent memory that is used to store parameters for configured PCI devices.

The PCI configuration space accessed by UnixWare 7 and SCO OpenServer drivers is the same, although the conventions used to access that space are different; see ``PCI'' for more information.

The figure below depicts the layout of the 64-byte predefined header portion of the 256-byte configuration space that every PCI device supports.

31 16 15 0 ------------------------------------------------- | Device ID | Vendor ID | 0x00 ------------------------------------------------- | Status | Command | 0x04 ------------------------------------------------- | Class Code | Rev ID. | 0x08 ------------------------------------------------- | BIST | Hdr_Type | Lat_Timer |Cache_Ln_Sz| 0x0c ------------------------------------------------- | | 0x10 ------------------------------------------------- | | 0x14 ------------------------------------------------- | | 0x18 ------------------------------------------------- | | 0x1c ------------------------------------------------- | | 0x20 ------------------------------------------------- | | 0x24 ------------------------------------------------- | Cardbus CIS Pointer** | 0x28 ------------------------------------------------- | Subsystem ID** | Subsystem Vendor ID** | 0x2c ------------------------------------------------- | Expansion ROM base address | 0x30 ------------------------------------------------- | Reserved | 0x34 ------------------------------------------------- | Reserved | 0x38 ------------------------------------------------- | Max_Lat | Min_Gnt | Intr Pin. | Intr line | 0x3c -------------------------------------------------

** Field is reserved in PCI 2.0 specification

See the appropriate version of the PCI Local Bus Specification for details on the configuration header fields.

Usage

UnixWare 7 and SCO OpenServer drivers use different conventions to access PCI configuration space. See ``PCI'' for information about accessing PCI configuration space from the command line; the following information discusses how device driver code accesses PCI configuration information.

DDI access to PCI configuration information

DDI drivers can access PCI configuration space in the following ways:

Use the CM_BRDID parameter documented on the cm_params(D5) manual page to access ``Vendor ID'' and ``Device ID''.
Use the CM_SBRDID parameter documented on the cm_params(D5) manual page to access ``Subsystem Vendor ID'' and ``Subsystem ID''.

ODDI access to PCI configuration information

SCO OpenServer ODDI drivers access PCI configuration space using the functions documented on the pci_read(D3oddi) and pci_write(D3oddi) manual pages.

Use the appropriate form of the function for the size of the field to be accessed, and specify the offset of the field in the third argument. For example, use pci_readword( ) and pci_writeword( ) with 0x02 as the third argument to access the ``Device ID''.

HPCI access to PCI configuration information

HPCD drivers that use the HPCI interface can access all fields in PCI configuration space using the functions documented on the pci_read(D3hpci) and pci_write(D3hpci) manual pages.

Use the appropriate form of the function for the size of the field to be accessed, and specify the offset of the field in the fourth argument. For example, use pci_read_word( ) and pci_write_word( ) with 0x02 as the third argument to access the ``Device ID''.

Hardware applicability

x86/Pentium compatible architectures with a PCI bus configured.

Version pplicability

ddi: 1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp

oddi: 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp

SCO OpenServer and UnixWare 7 compatibility

The configuration space layout is determined by industry standards boards; drivers written for UnixWare 7 and SCO OpenServer access the same configuration space, although they use different methods for that access. See ``PCI'' for details about how drivers on both platforms access device configuration space.

References

cm_read_devconfig(D3), cm_write_devconfig(D3), cm_params(D5)

pci(HW), cm_params(D5), eisa_parse_devconfig(D3), pci_read(D3oddi), pci_write(D3oddi), pci(D4oddi)

``PCI''
PCI Local Bus Specification, Revision 2.0