707 lines
18 KiB
Groff
707 lines
18 KiB
Groff
.\"
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.\" Copyright (c) 2005 Bruce M Simpson <bms@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 30, 2007
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.Dt PCI 9
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.Os
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.Sh NAME
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.Nm pci ,
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.Nm pci_alloc_msi ,
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.Nm pci_alloc_msix ,
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.Nm pci_disable_busmaster ,
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.Nm pci_disable_io ,
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.Nm pci_enable_busmaster ,
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.Nm pci_enable_io ,
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.Nm pci_find_bsf ,
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.Nm pci_find_cap ,
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.Nm pci_find_dbsf ,
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.Nm pci_find_device ,
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.Nm pci_find_extcap ,
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.Nm pci_find_htcap ,
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.Nm pci_get_max_read_req ,
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.Nm pci_get_powerstate ,
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.Nm pci_get_vpd_ident ,
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.Nm pci_get_vpd_readonly ,
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.Nm pci_msi_count ,
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.Nm pci_msix_count ,
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.Nm pci_pending_msix ,
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.Nm pci_read_config ,
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.Nm pci_release_msi ,
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.Nm pci_remap_msix ,
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.Nm pci_restore_state ,
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.Nm pci_save_state ,
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.Nm pci_set_max_read_req ,
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.Nm pci_set_powerstate ,
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.Nm pci_write_config
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.Nd PCI bus interface
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.Sh SYNOPSIS
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.In sys/bus.h
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.In dev/pci/pcireg.h
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.In dev/pci/pcivar.h
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.Ft int
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.Fn pci_alloc_msi "device_t dev" "int *count"
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.Ft int
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.Fn pci_alloc_msix "device_t dev" "int *count"
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.Ft int
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.Fn pci_disable_busmaster "device_t dev"
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.Ft int
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.Fn pci_disable_io "device_t dev" "int space"
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.Ft int
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.Fn pci_enable_busmaster "device_t dev"
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.Ft int
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.Fn pci_enable_io "device_t dev" "int space"
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.Ft device_t
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.Fn pci_find_bsf "uint8_t bus" "uint8_t slot" "uint8_t func"
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.Ft int
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.Fn pci_find_cap "device_t dev" "int capability" "int *capreg"
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.Ft device_t
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.Fn pci_find_dbsf "uint32_t domain" "uint8_t bus" "uint8_t slot" "uint8_t func"
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.Ft device_t
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.Fn pci_find_device "uint16_t vendor" "uint16_t device"
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.Ft int
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.Fn pci_find_extcap "device_t dev" "int capability" "int *capreg"
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.Ft int
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.Fn pci_find_htcap "device_t dev" "int capability" "int *capreg"
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.Ft int
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.Fn pci_get_max_read_req "device_t dev"
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.Ft int
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.Fn pci_get_powerstate "device_t dev"
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.Ft int
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.Fn pci_get_vpd_ident "device_t dev" "const char **identptr"
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.Ft int
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.Fn pci_get_vpd_readonly "device_t dev" "const char *kw" "const char **vptr"
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.Ft int
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.Fn pci_msi_count "device_t dev"
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.Ft int
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.Fn pci_msix_count "device_t dev"
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.Ft int
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.Fn pci_pending_msix "device_t dev" "u_int index"
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.Ft uint32_t
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.Fn pci_read_config "device_t dev" "int reg" "int width"
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.Ft int
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.Fn pci_release_msi "device_t dev"
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.Ft int
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.Fn pci_remap_msix "device_t dev" "int count" "const u_int *vectors"
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.Ft void
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.Fn pci_restore_state "device_t dev"
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.Ft void
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.Fn pci_save_state "device_t dev"
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.Ft int
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.Fn pci_set_max_read_req "device_t dev" "int size"
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.Ft int
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.Fn pci_set_powerstate "device_t dev" "int state"
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.Ft void
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.Fn pci_write_config "device_t dev" "int reg" "uint32_t val" "int width"
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.Sh DESCRIPTION
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The
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.Nm
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set of functions are used for managing PCI devices.
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The functions are split into several groups:
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raw configuration access,
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locating devices,
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device information,
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device configuration,
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and
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message signaled interrupts.
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.Ss Raw Configuration Access
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The
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.Fn pci_read_config
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function is used to read data from the PCI configuration
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space of the device
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.Fa dev ,
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at offset
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.Fa reg ,
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with
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.Fa width
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specifying the size of the access.
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.Pp
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The
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.Fn pci_write_config
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function is used to write the value
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.Fa val
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to the PCI configuration
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space of the device
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.Fa dev ,
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at offset
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.Fa reg ,
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with
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.Fa width
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specifying the size of the access.
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.Pp
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.Em NOTE :
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Device drivers should only use these functions for functionality that
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is not available via another
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.Fn pci
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function.
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.Ss Locating Devices
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The
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.Fn pci_find_bsf
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function looks up the
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.Vt device_t
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of a PCI device, given its
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.Fa bus ,
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.Fa slot ,
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and
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.Fa func .
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The
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.Fa slot
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number actually refers to the number of the device on the bus,
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which does not necessarily indicate its geographic location
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in terms of a physical slot.
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Note that in case the system has multiple PCI domains,
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the
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.Fn pci_find_bsf
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function only searches the first one.
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Actually, it is equivalent to:
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.Bd -literal -offset indent
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pci_find_dbsf(0, bus, slot, func);
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.Ed
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.Pp
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The
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.Fn pci_find_dbsf
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function looks up the
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.Vt device_t
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of a PCI device, given its
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.Fa domain ,
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.Fa bus ,
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.Fa slot ,
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and
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.Fa func .
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The
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.Fa slot
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number actually refers to the number of the device on the bus,
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which does not necessarily indicate its geographic location
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in terms of a physical slot.
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.Pp
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The
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.Fn pci_find_device
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function looks up the
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.Vt device_t
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of a PCI device, given its
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.Fa vendor
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and
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.Fa device
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IDs.
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Note that there can be multiple matches for this search; this function
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only returns the first matching device.
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.Ss Device Information
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The
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.Fn pci_find_cap
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function is used to locate the first instance of a PCI capability
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register set for the device
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.Fa dev .
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The capability to locate is specified by ID via
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.Fa capability .
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Constant macros of the form
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.Dv PCIY_xxx
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for standard capability IDs are defined in
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.In dev/pci/pcireg.h .
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If the capability is found, then
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.Fa *capreg
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is set to the offset in configuration space of the capability register set,
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and
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.Fn pci_find_cap
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returns zero.
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If the capability is not found or the device does not support capabilities,
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.Fn pci_find_cap
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returns an error.
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.Pp
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The
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.Fn pci_find_extcap
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function is used to locate the first instance of a PCI-express
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extended capability register set for the device
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.Fa dev .
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The extended capability to locate is specified by ID via
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.Fa capability .
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Constant macros of the form
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.Dv PCIZ_xxx
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for standard extended capability IDs are defined in
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.In dev/pci/pcireg.h .
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If the extended capability is found, then
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.Fa *capreg
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is set to the offset in configuration space of the extended capability
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register set, and
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.Fn pci_find_extcap
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returns zero.
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If the extended capability is not found or the device is not a
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PCI-express device,
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.Fn pci_find_extcap
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returns an error.
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.Pp
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The
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.Fn pci_find_htcap
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function is used to locate the first instance of a HyperTransport capability
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register set for the device
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.Fa dev .
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The capability to locate is specified by type via
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.Fa capability .
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Constant macros of the form
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.Dv PCIM_HTCAP_xxx
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for standard HyperTransport capability types are defined in
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.In dev/pci/pcireg.h .
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If the capability is found, then
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.Fa *capreg
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is set to the offset in configuration space of the capability register set,
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and
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.Fn pci_find_htcap
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returns zero.
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If the capability is not found or the device is not a HyperTransport device,
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.Fn pci_find_htcap
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returns an error.
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.Pp
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The
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.Fn pci_get_vpd_ident
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function is used to fetch a device's Vital Product Data
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.Pq VPD
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identifier string.
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If the device
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.Fa dev
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supports VPD and provides an identifier string,
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then
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.Fa *identptr
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is set to point at a read-only, null-terminated copy of the identifier
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string,
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and
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.Fn pci_get_vpd_ident
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returns zero.
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If the device does not support VPD or does not provide an identifier
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string,
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then
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.Fn pci_get_vpd_ident
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returns an error.
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.Pp
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The
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.Fn pci_get_vpd_readonly
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function is used to fetch the value of a single VPD read-only keyword
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for the device
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.Fa dev .
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The keyword to fetch is identified by the two character string
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.Fa kw .
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If the device supports VPD and provides a read-only value for the
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requested keyword,
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then
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.Fa *vptr
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is set to point at a read-only, null-terminated copy of the value,
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and
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.Fn pci_get_vpd_readonly
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returns zero.
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If the device does not support VPD or does not provide the requested
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keyword,
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then
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.Fn pci_get_vpd_readonly
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returns an error.
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.Ss Device Configuration
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The
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.Fn pci_enable_busmaster
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function enables PCI bus mastering for the device
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.Fa dev ,
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by setting the
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.Dv PCIM_CMD_BUSMASTEREN
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bit in the
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.Dv PCIR_COMMAND
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register.
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The
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.Fn pci_disable_busmaster
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function clears this bit.
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.Pp
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The
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.Fn pci_enable_io
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function enables memory or I/O port address decoding for the device
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.Fa dev ,
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by setting the
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.Dv PCIM_CMD_MEMEN
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or
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.Dv PCIM_CMD_PORTEN
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bit in the
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.Dv PCIR_COMMAND
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register appropriately.
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The
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.Fn pci_disable_io
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function clears the appropriate bit.
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The
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.Fa space
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argument specifies which resource is affected; this can be either
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.Dv SYS_RES_MEMORY
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or
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.Dv SYS_RES_IOPORT
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as appropriate.
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Device drivers should generally not use these routines directly.
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The PCI bus will enable decoding automatically when a
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.Dv SYS_RES_MEMORY
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or
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.Dv SYS_RES_IOPORT
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resource is activated via
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.Xr bus_alloc_resource 9
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or
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.Xr bus_activate_resource 9 .
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.Pp
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The
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.Fn pci_get_max_read_req
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function returns the current maximum read request size in bytes for a
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PCI-express device.
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If the
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.Fa dev
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device is not a PCI-express device,
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.Fn pci_get_max_read_req
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returns zero.
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.Pp
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The
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.Fn pci_set_max_read_req
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sets the PCI-express maximum read request size for
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.Fa dev .
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The requested
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.Fa size
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may be adjusted,
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and
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.Fn pci_set_max_read_req
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returns the actual size set in bytes.
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If the
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.Fa dev
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device is not a PCI-express device,
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.Fn pci_set_max_read_req
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returns zero.
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.Pp
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The
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.Fn pci_get_powerstate
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function returns the current power state of the device
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.Fa dev .
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If the device does not support power management capabilities, then the default
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state of
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.Dv PCI_POWERSTATE_D0
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is returned.
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The following power states are defined by PCI:
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.Bl -hang -width ".Dv PCI_POWERSTATE_UNKNOWN"
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.It Dv PCI_POWERSTATE_D0
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State in which device is on and running.
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It is receiving full power from the system and delivering
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full functionality to the user.
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.It Dv PCI_POWERSTATE_D1
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Class-specific low-power state in which device context may or
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may not be lost.
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Busses in this state cannot do anything to the bus, to
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force devices to lose context.
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.It Dv PCI_POWERSTATE_D2
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Class-specific low-power state in which device context may or
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may not be lost.
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Attains greater power savings than
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.Dv PCI_POWERSTATE_D1 .
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Busses in this state can cause devices to lose some context.
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Devices
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.Em must
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be prepared for the bus to be in this state or higher.
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.It Dv PCI_POWERSTATE_D3
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State in which the device is off and not running.
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Device context is lost, and power from the device can
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be removed.
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.It Dv PCI_POWERSTATE_UNKNOWN
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State of the device is unknown.
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.El
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.Pp
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The
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.Fn pci_set_powerstate
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function is used to transition the device
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.Fa dev
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to the PCI power state
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.Fa state .
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If the device does not support power management capabilities or
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it does not support the specific power state
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.Fa state ,
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then the function will fail with
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.Er EOPNOTSUPP .
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.Pp
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The
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.Fn pci_save_state
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and
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.Fn pci_restore_state
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functions can be used by a device driver to save and restore standard PCI
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config registers.
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The
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.Fn pci_save_state
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function must be invoked while the device has valid state before
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.Fn pci_restore_state
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can be used.
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If the device is not in the fully-powered state
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.Pq Dv PCI_POWERSTATE_D0
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when
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.Fn pci_restore_state
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is invoked,
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then the device will be transitioned to
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.Dv PCI_POWERSTATE_D0
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before any config registers are restored.
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.Ss Message Signaled Interrupts
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Message Signaled Interrupts
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.Pq MSI
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and
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Enhanced Message Signaled Interrupts
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.Pq MSI-X
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are PCI capabilities that provide an alternate method for PCI
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devices to signal interrupts.
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The legacy INTx interrupt is available to PCI devices as a
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.Dv SYS_RES_IRQ
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resource with a resource ID of zero.
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MSI and MSI-X interrupts are available to PCI devices as one or more
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.Dv SYS_RES_IRQ
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resources with resource IDs greater than zero.
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A driver must ask the PCI bus to allocate MSI or MSI-X interrupts
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using
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.Fn pci_alloc_msi
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or
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.Fn pci_alloc_msix
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before it can use MSI or MSI-X
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.Dv SYS_RES_IRQ
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resources.
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A driver is not allowed to use the legacy INTx
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.Dv SYS_RES_IRQ
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resource if MSI or MSI-X interrupts have been allocated,
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and attempts to allocate MSI or MSI-X interrupts will fail if the
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driver is currently using the legacy INTx
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.Dv SYS_RES_IRQ
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resource.
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A driver is only allowed to use either MSI or MSI-X,
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but not both.
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.Pp
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The
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.Fn pci_count_msi
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function returns the maximum number of MSI messages supported by the
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device
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.Fa dev.
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If the device does not support MSI,
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then
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.Fn pci_count_msi
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returns zero.
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.Pp
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The
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.Fn pci_alloc_msi
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function attempts to allocate
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.Fa *count
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MSI messages for the device
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.Fa dev .
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The
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.Fn pci_alloc_msi
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function may allocate fewer messages than requested for various
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reasons including requests for more messages than the device
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.Fa dev
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supports,
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or if the system has a shortage of available MSI messages.
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On success,
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.Fa *count
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is set to the number of messages allocated and
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.Fn pci_alloc_msi
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returns zero.
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The
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.Dv SYS_RES_IRQ
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resources for the allocated messages will be available at consecutive
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resource IDs beginning with one.
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If
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.Fn pci_alloc_msi
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is not able to allocate any messages,
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it returns an error.
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Note that MSI only supports message counts that are powers of two;
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requests to allocate a non-power of two count of messages will fail.
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.Pp
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The
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.Fn pci_release_msi
|
|
function is used to release any allocated MSI or MSI-X messages back
|
|
to the system.
|
|
If any MSI or MSI-X
|
|
.Dv SYS_RES_IRQ
|
|
resources are allocated by the driver or have a configured interrupt
|
|
handler,
|
|
this function will fail with
|
|
.Er EBUSY .
|
|
The
|
|
.Fn pci_release_msi
|
|
function returns zero on success and an error on failure.
|
|
.Pp
|
|
The
|
|
.Fn pci_count_msix
|
|
function returns the maximum number of MSI-X messages supported by the
|
|
device
|
|
.Fa dev .
|
|
If the device does not support MSI-X,
|
|
then
|
|
.Fn pci_count_msix
|
|
returns zero.
|
|
.Pp
|
|
The
|
|
.Fn pci_alloc_msix
|
|
function attempts to allocate
|
|
.Fa *count
|
|
MSI-X messages for the device
|
|
.Fa dev .
|
|
The
|
|
.Fn pci_alloc_msix
|
|
function may allocate fewer messages than requested for various
|
|
reasons including requests for more messages than the device
|
|
.Fa dev
|
|
supports,
|
|
or if the system has a shortage of available MSI-X messages.
|
|
On success,
|
|
.Fa *count
|
|
is set to the number of messages allocated and
|
|
.Fn pci_alloc_msix
|
|
returns zero.
|
|
For MSI-X messages,
|
|
the resource ID for each
|
|
.Dv SYS_RES_IRQ resource identifies the index in the MSI-X table of the
|
|
corresponding message.
|
|
A resource ID of one maps to the first index of the MSI-X table;
|
|
a resource ID two identifies the second index in the table, etc.
|
|
The
|
|
.Fn pci_alloc_msix
|
|
function assigns the
|
|
.Fa *count
|
|
messages allocated to the first
|
|
.Fa *count
|
|
table indicies.
|
|
If
|
|
.Fn pci_alloc_msix
|
|
is not able to allocate any messages,
|
|
it returns an error.
|
|
Unlike MSI,
|
|
MSI-X does not require message counts that are powers of two.
|
|
.Pp
|
|
The
|
|
.Fn pci_pending_msix
|
|
function examines the
|
|
.Fa dev
|
|
device's Pending Bit Array
|
|
.Pq PBA
|
|
to determine the pending status of the MSI-X message at table index
|
|
.Fa index .
|
|
If the indicated message is pending,
|
|
this function returns a non-zero value;
|
|
otherwise,
|
|
it returns zero.
|
|
Passing an invalid
|
|
.Fa index
|
|
to this function will result in undefined behavior.
|
|
.Pp
|
|
As mentioned in the description of
|
|
.Fn pci_alloc_msix ,
|
|
MSI-X messages are initially assigned to the first N table entries.
|
|
A driver may use a different distribution of available messages to
|
|
table entries via the
|
|
.Fn pci_remap_msix
|
|
function.
|
|
Note that this function must be called after a succesful call to
|
|
.Fn pci_alloc_msix
|
|
but before any of the
|
|
.Dv SYS_RES_IRQ
|
|
resources are allocated.
|
|
The
|
|
.Fn pci_remap_msix
|
|
function returns zero on success,
|
|
or an error on failure.
|
|
.Pp
|
|
The
|
|
.Fa vectors
|
|
array should contain
|
|
.Fa count
|
|
message vectors.
|
|
The array maps directly to the MSI-X table in that the first entry in
|
|
the array specifies the message used for the first entry in the MSI-X
|
|
table,
|
|
the second entry in the array corresponds to the second entry in the
|
|
MSI-X table,
|
|
etc.
|
|
The vector value in each array index can either be zero to indicate
|
|
that no message should be assigned to the corresponding MSI-X table entry,
|
|
or it can be a number from one to N
|
|
.Po
|
|
where N is the count returned from the previous call to
|
|
.Fn pci_alloc_msix
|
|
.Pc
|
|
to indicate which of the allocated messages should be assigned to the
|
|
corresponding MSI-X table entry.
|
|
.Pp
|
|
If
|
|
.Fn pci_remap_msix
|
|
succeeds,
|
|
each MSI-X table entry with a non-zero vector will have an associated
|
|
.Dv SYS_RES_IRQ
|
|
resource whose resource ID corresponds to the table index as described
|
|
above for
|
|
.Fn pci_alloc_msix .
|
|
MSI-X table entries that with a vector of zero will not have an
|
|
associated
|
|
.Dv SYS_RES_IRQ resource.
|
|
Additionally,
|
|
if any of the original messages allocated by
|
|
.Fn pci_alloc_msix
|
|
are not used in the new distribution of messages in the MSI-X table,
|
|
they will be released automatically.
|
|
Note that if a driver wishes to use fewer messages than were allocated by
|
|
.Fn pci_alloc_msix ,
|
|
the driver must use a single, contiguous range of messages beginning
|
|
with one in the new distribution.
|
|
The
|
|
.Fn pci_remap_msix
|
|
function will fail if this condition is not met.
|
|
.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
|
|
and
|
|
.An John Baldwin Aq jhb@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.
|