.\" .\" Copyright (c) 2005 Bruce M Simpson .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD$ .\" .Dd September 30, 2007 .Dt PCI 9 .Os .Sh NAME .Nm pci , .Nm pci_disable_busmaster , .Nm pci_disable_io , .Nm pci_enable_busmaster , .Nm pci_enable_io , .Nm pci_find_bsf , .Nm pci_find_dbsf , .Nm pci_find_device , .Nm pci_get_powerstate , .Nm pci_read_config , .Nm pci_restore_state , .Nm pci_save_state , .Nm pci_set_powerstate , .Nm pci_write_config .Nd PCI bus interface .Sh SYNOPSIS .In sys/bus.h .In dev/pci/pcivar.h .In dev/pci/pcireg.h .In machine/pci_cfgreg.h .Ft int .Fn pci_disable_busmaster "device_t dev" .Ft int .Fn pci_disable_io "device_t dev" "int space" .Ft int .Fn pci_enable_busmaster "device_t dev" .Ft int .Fn pci_enable_io "device_t dev" "int space" .Ft device_t .Fn pci_find_bsf "uint8_t bus" "uint8_t slot" "uint8_t func" .Ft device_t .Fn pci_find_dbsf "uint32_t domain" "uint8_t bus" "uint8_t slot" "uint8_t func" .Ft device_t .Fn pci_find_device "uint16_t vendor" "uint16_t device" .Ft int .Fn pci_get_powerstate "device_t dev" .Ft uint32_t .Fn pci_read_config "device_t dev" "int reg" "int width" .Ft void .Fn pci_restore_state "device_t dev" .Ft void .Fn pci_save_state "device_t dev" .Ft int .Fn pci_set_powerstate "device_t dev" "int state" .Ft void .Fn pci_write_config "device_t dev" "int reg" "uint32_t val" "int width" .Sh DESCRIPTION The .Nm set of functions are used for managing PCI devices. .Pp The .Fn pci_read_config function is used to read data from the PCI configuration space of the device .Fa dev , at offset .Fa reg , with .Fa width specifying the size of the access. .Pp The .Fn pci_write_config function is used to write the value .Fa val to the PCI configuration space of the device .Fa dev , at offset .Fa reg , with .Fa width specifying the size of the access. .Pp The .Fn pci_enable_busmaster function enables PCI bus mastering for the device .Fa dev , by setting the .Dv PCIM_CMD_BUSMASTEREN bit in the .Dv PCIR_COMMAND register. The .Fn pci_disable_busmaster function clears this bit. .Pp The .Fn pci_enable_io function enables memory or I/O port address decoding for the device .Fa dev , by setting the .Dv PCIM_CMD_MEMEN or .Dv PCIM_CMD_PORTEN bit in the .Dv PCIR_COMMAND register appropriately. The .Fn pci_disable_io function clears the appropriate bit. The .Fa space argument specifies which resource is affected; this can be either .Dv SYS_RES_MEMORY or .Dv SYS_RES_IOPORT as appropriate. .Pp .Em NOTE : These functions should be used in preference to manually manipulating the configuration space. .Pp The .Fn pci_get_powerstate function returns the current power state of the device .Fa dev . If the device does not support power management capabilities, then the default state of .Dv PCI_POWERSTATE_D0 is returned. The following power states are defined by PCI: .Bl -hang -width ".Dv PCI_POWERSTATE_UNKNOWN" .It Dv PCI_POWERSTATE_D0 State in which device is on and running. It is receiving full power from the system and delivering full functionality to the user. .It Dv PCI_POWERSTATE_D1 Class-specific low-power state in which device context may or may not be lost. Busses in this state cannot do anything to the bus, to force devices to lose context. .It Dv PCI_POWERSTATE_D2 Class-specific low-power state in which device context may or may not be lost. Attains greater power savings than .Dv PCI_POWERSTATE_D1 . Busses in this state can cause devices to lose some context. Devices .Em must be prepared for the bus to be in this state or higher. .It Dv PCI_POWERSTATE_D3 State in which the device is off and not running. Device context is lost, and power from the device can be removed. .It Dv PCI_POWERSTATE_UNKNOWN State of the device is unknown. .El .Pp The .Fn pci_set_powerstate function is used to transition the device .Fa dev to the PCI power state .Fa state . If the device does not support power management capabilities or it does not support the specific power state .Fa state , then the function will fail with .Er EOPNOTSUPP . .Pp The .Fn pci_save_state and .Fn pci_restore_state functions can be used by a device driver to save and restore standard PCI config registers. The .Fn pci_save_state function must be invoked while the device has valid state before .Fn pci_restore_state can be used. If the device is not in the fully-powered state .Pq Dv PCI_POWERSTATE_D0 when .Fn pci_restore_state is invoked, then the device will be transitioned to .Dv PCI_POWERSTATE_D0 before any config registers are restored. .Pp The .Fn pci_find_bsf function looks up the .Vt device_t of a PCI device, given its .Fa bus , .Fa slot , and .Fa func . The .Fa slot number actually refers to the number of the device on the bus, which does not necessarily indicate its geographic location in terms of a physical slot. Note that in case the system has multiple PCI domains, the .Fn pci_find_bsf function only searches the first one. Actually, it is equivalent to: .Bd -literal -offset indent pci_find_dbsf(0, bus, slot, func); .Ed .Pp The .Fn pci_find_dbsf function looks up the .Vt device_t of a PCI device, given its .Fa domain , .Fa bus , .Fa slot , and .Fa func . The .Fa slot number actually refers to the number of the device on the bus, which does not necessarily indicate its geographic location in terms of a physical slot. .Pp The .Fn pci_find_device function looks up the .Vt device_t of a PCI device, given its .Fa vendor and .Fa device IDs. Note that there can be multiple matches for this search; this function only returns the first matching device. .Sh IMPLEMENTATION NOTES The .Vt pci_addr_t type varies according to the size of the PCI bus address space on the target architecture. .Sh SEE ALSO .Xr pci 4 , .Xr pciconf 8 , .Xr bus_alloc_resource 9 , .Xr bus_dma 9 , .Xr bus_release_resource 9 , .Xr bus_setup_intr 9 , .Xr bus_teardown_intr 9 , .Xr devclass 9 , .Xr device 9 , .Xr driver 9 , .Xr rman 9 .Rs .%B FreeBSD Developers' Handbook .%T NewBus .%U http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers-handbook/ .Re .Rs .%A Shanley .%A Anderson .%B PCI System Architecture .%N 2nd Edition .%I Addison-Wesley .%O ISBN 0-201-30974-2 .Re .Sh AUTHORS This manual page was written by .An Bruce M Simpson Aq bms@FreeBSD.org . .Sh BUGS The kernel PCI code has a number of references to .Dq "slot numbers" . These do not refer to the geographic location of PCI devices, but to the device number assigned by the combination of the PCI IDSEL mechanism and the platform firmware. This should be taken note of when working with the kernel PCI code.