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.\" $FreeBSD$ 25.\" 26.Dd June 10, 2021 27.Dt MMC 4 28.Os 29.Sh NAME 30.Nm mmc 31.Nd MultiMediaCard and SD Card bus driver 32.Sh SYNOPSIS 33.Cd device mmc 34.Sh DESCRIPTION 35The 36.Nm 37driver implements the MMC and SD Card bus. 38The 39.Nm 40driver supports all MMC and SD bridges in the system. 41All SD or MMC cards in the system attach to an instance of 42.Nm . 43The 44.Nm 45bus typically has only one slot, and only memory cards. 46MultiMediaCards exist only in memory. 47SD Cards exist as memory, I/O, or combination cards. 48.Sh SEE ALSO 49.Xr mmcsd 4 , 50.Xr sdhci 4 51.Rs 52.%T "SD Specifications, Part 1, Physical Layer, Simplified Specification" 53.Re 54.Rs 55.%T "The MultiMediaCard System Specification" 56.Re 57.Sh BUGS 58SDIO cards currently do not work. 59