Port rtsx(4) driver for Realtek SD card reader from OpenBSD.

This driver provides support for Realtek PCI SD card readers.  It attaches
mmc(4) bus on card insertion and detaches it on card removal.  It has been
tested with RTS5209, RTS5227, RTS5229, RTS522A, RTS525A and RTL8411B.  It
should also work with RTS5249, RTL8402 and RTL8411.

PR:			204521
Submitted by:		Henri Hennebert (hlh at restart dot be)
Reviewed by:		imp, jkim
Differential Revision:	https://reviews.freebsd.org/D26435

2 files changed, 122 insertions, 0 deletions

diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index 3f171789a73d..e4ed64afd8ec 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -446,6 +446,7 @@ MAN=	aac.4 \
 	rl.4 \
 	rndtest.4 \
 	route.4 \
+	rtsx.4 \
 	rtwn.4 \
 	rtwnfw.4 \
 	rtwn_pci.4 \
diff --git a/share/man/man4/rtsx.4 b/share/man/man4/rtsx.4
new file mode 100644
index 000000000000..3f2ffcf6be66
--- /dev/null
+++ b/share/man/man4/rtsx.4
@@ -0,0 +1,121 @@
+.\"
+.\" Copyright (c) 2020 Henri Hennebert <hlh@restart.be>
+.\" All rights reserved.
+.\"
+.\" 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. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 24, 2020
+.Dt RTSX 4
+.Os
+.Sh NAME
+.Nm rtsx
+.Nd Realtek SD card reader
+.Sh SYNOPSIS
+To compile this driver into the kernel, place the following
+lines in the kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device mmc"
+.Cd "device mmcsd"
+.Cd "device rtsx"
+.Ed
+.Pp
+Alternatively, to load the driver as a module at boot time,
+place the following lines in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+mmc_load="YES"
+mmcsd_load="YES"
+rtsx_load="YES"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+driver provides support for Realtek SD card reader.
+Driver attaches mmc bus on card insertion and detaches it on card removing.
+.Sh HARDWARE
+The
+.Nm
+driver supports different specification compatible chips.
+The following chips have been verified to work:
+.Pp
+.Bl -bullet -compact
+.It
+RTS5209
+.It
+RTS5227
+.It
+RTS5229
+.It
+RTS522A
+.It
+RTS525A
+.It
+RTL8411B
+.El
+.Pp
+It should also work for:
+.Pp
+.Bl -bullet -compact
+.It
+RTS5249
+.It
+RTL8402
+.It
+RTL8411
+.El
+.Sh SEE ALSO
+.Xr mmc 4 ,
+.Xr mmcsd 4
+.Rs
+.%T "SD Specifications, Part 2, SD Host Controller, Simplified Specification"
+.%T "SanDisk Secure Digital Card"
+.Re
+.Sh HISTORY
+The
+.Nm
+driver was ported from
+.Ox
+with modifications found in Linux and
+.Nx .
+.Sh AUTHORS
+.An Henri Hennebert Aq Mt hlh@restart.be
+.An Gary Jennejohn Aq Mt gj@freebsd.org
+.An Jesper Schmitz Mouridsen Aq Mt jsm@FreeBSD.org
+.Sh CONTRIBUTORS
+.An Lutz Bichler Aq Mt Lutz.Bichler@gmail.com
+.Sh BUGS
+.Bl -bullet
+.It
+The timeouts experienced during card insert and during I/O are solved in version 1.0g.
+.It
+RTS522A on Lenovo P50s and Lenovo T470p, card detection and read-only switch are reversed.
+This is sovled by adding in
+.Em loader.conf(5) :
+.Bd -ragged
+.Cd dev.rtsx.0.inversion=1
+.Ed
+.It
+Mounting a filesystem with write access on a card write protected may involve a kernel crash.
+.It
+Suspend/Resume do not work under MMCCAM.
+.El