1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2003 M. Warner Losh <imp@FreeBSD.org> 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.Dd March 13, 2024 26.Dt BUS_ACTIVATE_RESOURCE 9 27.Os 28.Sh NAME 29.Nm bus_activate_resource , bus_deactivate_resource 30.Nd activate or deactivate a resource 31.Sh SYNOPSIS 32.In sys/param.h 33.In sys/bus.h 34.Pp 35.In machine/bus.h 36.In sys/rman.h 37.In machine/resource.h 38.Ft int 39.Fo bus_activate_resource 40.Fa "device_t dev" "struct resource *r" 41.Fc 42.Ft int 43.Fo bus_deactivate_resource 44.Fa "device_t dev" "struct resource *r" 45.Fc 46.Sh DESCRIPTION 47These functions activate or deactivate a previously allocated resource. 48In general, resources must be activated before they can be accessed by 49the driver. 50Bus drivers may perform additional actions to ensure that the resource is 51ready to be accessed. 52For example, 53the PCI bus driver enables memory decoding in a PCI device's command register 54when activating a memory resource. 55.Pp 56The arguments are as follows: 57.Bl -tag -width indent 58.It Fa dev 59The device that requests ownership of the resource. 60Before allocation, the resource is owned by the parent bus. 61.It Fa r 62A pointer to the 63.Vt "struct resource" 64returned by 65.Xr bus_alloc_resource 9 . 66.El 67.Ss Resource Mapping 68Resources which can be mapped for CPU access by a 69.Xr bus_space 9 70tag and handle will create a mapping of the entire resource when activated. 71The tag and handle for this mapping are stored in 72.Fa r 73and can be retrieved via 74.Xr rman_get_bustag 9 75and 76.Xr rman_get_bushandle 9 . 77These can be used with the 78.Xr bus_space 9 79API to access device registers or memory described by 80.Fa r . 81If the mapping is associated with a virtual address, 82the virtual address can be retrieved via 83.Xr rman_get_virtual 9 . 84.Pp 85This implicit mapping can be disabled by passing the 86.Dv RF_UNMAPPED 87flag to 88.Xr bus_alloc_resource 9 . 89A driver may use this if it wishes to allocate its own mappings of a resource 90using 91.Xr bus_map_resource 9 . 92.Pp 93A wrapper API for 94.Xr bus_space 9 95is also provided that accepts the associated resource as the first argument 96in place of the 97.Xr bus_space 9 98tag and handle. 99The functions in this wrapper API are named similarly to the 100.Xr bus_space 9 101API except that 102.Dq _space 103is removed from their name. 104For example, 105.Fn bus_read_4 106can be used in place of 107.Fn bus_space_read_4 . 108The wrapper API is preferred in new drivers. 109.Pp 110These two statements both read a 32-bit register at the start of a 111resource: 112.Bd -literal 113 bus_space_read_4(rman_get_bustag(res), rman_get_bushandle(res), 0); 114 bus_read_4(res, 0); 115.Ed 116.Sh RETURN VALUES 117Zero is returned on success, otherwise an error is returned. 118.Sh SEE ALSO 119.Xr bus_alloc_resource 9 , 120.Xr bus_map_resource 9 , 121.Xr bus_space 9 , 122.Xr device 9 , 123.Xr driver 9 124.Sh AUTHORS 125This manual page was written by 126.An Warner Losh Aq Mt imp@FreeBSD.org . 127