1.\" 2.\" Copyright (c) 2007 M. Warner Losh <imp@FreeBSD.org> 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. The name of the author may not be used to endorse or promote products 10.\" derived from this software without specific prior written permission. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.Dd June 10, 2021 25.Dt MMC 4 26.Os 27.Sh NAME 28.Nm mmc 29.Nd MultiMediaCard and SD Card bus driver 30.Sh SYNOPSIS 31.Cd device mmc 32.Sh DESCRIPTION 33The 34.Nm 35driver implements the MMC and SD Card bus. 36The 37.Nm 38driver supports all MMC and SD bridges in the system. 39All SD or MMC cards in the system attach to an instance of 40.Nm . 41The 42.Nm 43bus typically has only one slot, and only memory cards. 44MultiMediaCards exist only in memory. 45SD Cards exist as memory, I/O, or combination cards. 46.Sh SEE ALSO 47.Xr mmcsd 4 , 48.Xr sdhci 4 49.Rs 50.%T "SD Specifications, Part 1, Physical Layer, Simplified Specification" 51.Re 52.Rs 53.%T "The MultiMediaCard System Specification" 54.Re 55.Sh BUGS 56SDIO cards currently do not work. 57