.\" $NetBSD: autoconf.9,v 1.8 2001/12/13 19:29:32 gmcgarry Exp $ .\" .\" Copyright (c) 2001 The NetBSD Foundation, Inc. .\" All rights reserved. .\" .\" This code is derived from software contributed to The NetBSD Foundation .\" by Gregory McGarry. .\" .\" 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. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the NetBSD .\" Foundation, Inc. and its contributors. .\" 4. Neither the name of The NetBSD Foundation nor the names of its .\" contributors may be used to endorse or promote products derived .\" from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. .\" .Dd June 17, 2001 .Dt AUTOCONF 9 .Os .Sh NAME .Nm autoconf , .Nm config_search , .Nm config_found_sm , .Nm config_found , .Nm config_attach , .Nm config_detach , .Nm config_activate , .Nm config_deactivate , .Nm config_defer , .Nm config_interrupts , .Nm config_pending_incr , .Nm config_pending_decr .Nd autoconfiguration framework .Sh SYNOPSIS .Fd #include .Fd #include .Fd #include .Ft struct cfdata * .Fn config_search "cfmatch_t func" "struct device *parent" "void *aux" .Ft struct device * .Fn config_found_sm "struct device *parent" "void *aux" "cfprint_t print" \ "cfmatch_t submatch" .Ft struct device * .Fn config_found "struct device *parent" "void *aux" "cfprint_t print" .Ft struct device * .Fn config_attach "struct device *parent" "struct cfdata *cf" "void *aux" \ "cfprint_t print" .Ft int .Fn config_detach "struct device *dev" "int flags" .Ft int .Fn config_activate "struct device *dev" .Ft int .Fn config_deactivate "struct device *dev" .Ft int .Fn config_defer "struct device *dev" "void (*func)(struct device *)" .Ft void .Fn config_interrupts "struct device *dev" "void (*func)(struct device *)" .Ft void .Fn config_pending_incr .Ft void .Fn config_pending_decr .Sh DESCRIPTION Autoconfiguration is the process of matching hardware devices with an appropriate device driver. In its most basic form, autoconfiguration consists of the recursive process of finding and attaching all devices on a bus, including other busses. .Pp The autoconfiguration framework supports .Em direct configuration where the bus driver can determine the devices present. The autoconfiguration framework also supports .Em indirect configuration where the drivers must probe the bus looking the presence of a device. Direct configuration is preferred since it can find hardware regardless of the presence of proper drivers. .Pp The autoconfiguration process occurs at system bootstrap and is driven by a table generated from a .Do machine description .Dc file by .Xr config 8 . For a description of the .Xr config 8 .Do device definition .Dc language, see .Xr config 9 . .Pp Each device must have a name consisting of an alphanumeric string that ends with a unit number. The unit number identifies an instance of the driver. Device data structures are allocated dynamically during autoconfiguration, giving a unique address for each instance. .Sh FUNCTIONS .Bl -tag -width compact .It Fn config_search "func" "parent" "aux" Performs indirect configuration of physical devices. .Fn config_search iterates over all potential children, calling the given function .Fa func for each one. If .Fa func is NULL, .Fn config_search applies each child's match function instead. The argument .Fa parent is the pointer to the parent's device structure. The given .Fa aux argument describes the device that has been found and is simply passed on through .Fa func to the child. .Fn config_search returns a pointer to the best-matched child or NULL otherwise. .Pp The role of .Fa func is to call the match function for each device and call .Fn config_attach for any positive matches. If .Fa func is NULL, then the parent should record the return value from .Fn config_search and call .Fn config_attach itself. .Pp Note that this function is designed so that it can be used to apply an arbitrary function to all potential children. In this case callers may choose to ignore the return value. .It Fn config_found_sm "parent" "aux" "print" "submatch" Performs direct configuration on a physical device. .Fn config_found_sm is called by the parent and in turn calls the .Fa submatch function to call the match function as determined by the configuration table. If .Fa submatch is NULL, the driver match functions are called directly. The argument .Fa parent is the pointer to the parent's device structure. The given .Fa aux argument describes the device that has been found. The .Em softc structure for the matched device will be allocated, and the appropriate driver attach function will be called. If the device is matched, the system prints the name of the child and parent devices, and then calls the .Fa print function to produce addition information if desired. If no driver takes a match, the same .Fa print function is called to complain. The print function is called with the .Fa aux argument and, if the matches failed, the full name (including unit number) of the parent device, otherwise NULL. The .Fa print function must return an integer value. .Pp Two special strings, .Do not configured .Dc and .Do unsupported .Dc will be appended automatically to non-driver reports if the return value is UNCONF or UNSUPP respectively; otherwise the function should return the value QUIET. .Pp .Fn config_found_sm returns a pointer to the attached device's .Em softc structure if the device is attached, NULL otherwise. Most callers can ignore this value, since the system will already have printed a diagnostic. .It Fn config_found "parent" "aux" "print" This function is equivalent to calling .Fn config_found_sm "parent" "aux" "print" "submatch" with .Fa submatch set to NULL and is provided for compatibility with older drivers. .It Fn config_attach "parent" "cf" "aux" "print" Attach a found device. Allocates the memory for the .Em softc structure and calls the drivers attach function according to the configuration table. If successful, .Fn config_attach returns the .Em softc . If unsuccessful, it returns NULL. .It Fn config_detach "dev" "flags" Called by the parent to detach the child device. The second argument .Em flags contains detachment flags. Valid values are DETACH_FORCE (force detachment (eg. because of hardware removal) and DETACH_QUIET (do not print a notice). .Fn config_detach returns zero if successful and an error code otherwise. .Fn config_detach is always called from a thread context, allowing .Xr sleep 9 to be called while the device detaches itself. .It Fn config_activate "dev" Called by the parent to activate the child device .Fa dev . It is called to activate resources and initialise other kernel subsystems (such as the network subsystem). .Fn config_activate is called from interrupt contect after the device has been attached. .It Fn config_deactivate "dev" Called by the parent to deactivate the child device .Fa dev . .Fn config_deactivate is called from interrupt context to immediately relinquish resources and notify dependent kernel subsystems that the device is about to be detached. At some later point .Fn config_detach will be called to finalise the removal of the device. .It Fn config_defer "dev" "func" Called by the child to defer the remainder of its configuration until all its parent's devices have been attached. At this point, the function .Fa func is called with the argument .Fa dev . .It Fn config_interrupts "struct device *dev" "void (*func)(struct device *)" Called by the child to defer the remainder of its configuration until interrupts are enabled. At this point, the function .Fa func is called with the argument .Fa dev . .It Fn config_pending_incr Increment the .Va config_pending semaphore. It is used to account for deferred configurations before mounting the root file system. .It Fn config_pending_decr Decrement the .Va config_pending semaphore. It is used to account for deferred configurations before mounting the root file system. .El .Sh CODE REFERENCES This section describes places within the .Nx source tree where actual code implementing or utilising the autoconfiguration framework can be found. All pathnames are relative to .Pa /usr/src . .Pp The autoconfiguration framework itself is implemented within the file .Pa sys/kern/subr_autoconf.c . Data structures and function prototypes for the framework are located in .Pa sys/sys/device.h . .Sh SEE ALSO .Xr config 8 , .Xr config 9 , .Xr driver 9 .Sh HISTORY Autoconfiguration first appeared in .Bx 4.1 . The autoconfiguration framework was completely revised in .Bx 4.4 . The detach and activate/deactivate interfaces appeared in .Nx 1.5 .