1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2000 Alexander Langer 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.Dd April 19, 2022 30.Dt DRIVER_MODULE 9 31.Os 32.Sh NAME 33.Nm DRIVER_MODULE , 34.Nm DRIVER_MODULE_ORDERED , 35.Nm EARLY_DRIVER_MODULE , 36.Nm EARLY_DRIVER_MODULE_ORDERED 37.Nd kernel driver declaration macro 38.Sh SYNOPSIS 39.In sys/param.h 40.In sys/kernel.h 41.In sys/bus.h 42.In sys/module.h 43.Fn DRIVER_MODULE name busname "driver_t driver" "modeventhand_t evh" "void *arg" 44.Fn DRIVER_MODULE_ORDERED name busname "driver_t driver" "modeventhand_t evh" "void *arg" "int order" 45.Fn EARLY_DRIVER_MODULE name busname "driver_t driver" "modeventhand_t evh" "void *arg" "int pass" 46.Fn EARLY_DRIVER_MODULE_ORDERED name busname "driver_t driver" "modeventhand_t evh" "void *arg" "enum sysinit_elem_order order" "int pass" 47.Sh DESCRIPTION 48The 49.Fn DRIVER_MODULE 50macro declares a kernel driver. 51.Fn DRIVER_MODULE 52expands to the real driver declaration, where the phrase 53.Fa name 54is used as the naming prefix for the driver and its functions. 55Note that it is supplied as plain text, and not a 56.Li char 57or 58.Li char * . 59.Pp 60.Fa busname 61is the parent bus of the driver (PCI, ISA, PPBUS and others), e.g.\& 62.Ql pci , 63.Ql isa , 64or 65.Ql ppbus . 66.Pp 67The identifier used in 68.Fn DRIVER_MODULE 69can be different from the driver name. 70Also, the same driver identifier can exist on different buses, 71which is a pretty clean way of making front ends for different cards 72using the same driver on the same or different buses. 73For example, the following is allowed: 74.Pp 75.Fn DRIVER_MODULE foo isa foo_driver NULL NULL ; 76.Pp 77.Fn DRIVER_MODULE foo pci foo_driver NULL NULL ; 78.Pp 79.Fa driver 80is the driver of type 81.Li driver_t , 82which contains the information about the driver and is therefore one of the 83two most important parts of the call to 84.Fn DRIVER_MODULE . 85.Pp 86The 87.Fa evh 88argument is the event handler which is called when the driver (or module) 89is loaded or unloaded (see 90.Xr module 9 ) . 91.Pp 92The 93.Fa arg 94is unused at this time and should be a 95.Dv NULL 96pointer. 97.Pp 98The 99.Fn DRIVER_MODULE_ORDERED 100macro allows a driver to be registered in a specific order. 101This can be useful if a single kernel module contains multiple drivers 102that are inter-dependent. 103The 104.Fa order 105argument should be one of the 106.Xr SYSINIT 9 107initialization ordering constants 108.Pq Dv SI_ORDER_* . 109The default order for a driver module is 110.Dv SI_ORDER_MIDDLE . 111Typically a module will specify an order of 112.Dv SI_ORDER_ANY 113for a single driver to ensure it is registered last. 114.Pp 115The 116.Fn EARLY_DRIVER_MODULE 117macro allows a driver to be registered for a specific pass level. 118The boot time probe and attach process makes multiple passes over the 119device tree. 120Certain critical drivers that provide basic services needed by other 121devices are attached during earlier passes. 122Most drivers are attached in a final general pass. 123A driver that attaches during an early pass must register for a specific 124pass level 125.Pq BUS_PASS_* 126via the 127.Fa pass 128argument. 129Once a driver is registered it is available to attach to devices for 130all subsequent passes. 131.Pp 132The 133.Fn EARLY_DRIVER_MODULE_ORDERED 134macro allows a driver to be registered both in a specific order and 135for a specific pass level. 136.Sh SEE ALSO 137.Xr device 9 , 138.Xr driver 9 , 139.Xr module 9 , 140.Xr MODULE_PNP_INFO 9 , 141.Xr SYSINIT 9 142.Sh HISTORY 143Prior to 144.Fx 14.0 , 145these macros accepted an additional 146.Vt devclass_t 147argument after 148.Fa driver . 149.Sh AUTHORS 150This manual page was written by 151.An Alexander Langer Aq Mt alex@FreeBSD.org . 152