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As the boot order in the kernel continues to change, sometimes it may happen that the eSDHC controller mmc@2150000 (the one for eMMC) gets probed before the one at mmc@2140000 (for external SD cards). The effect is that the eMMC controller gets the /dev/mmcblk0 name, and the SD card gets /dev/mmcblk1. Since the introduction of this SoC, that has never happened in practice, even though it was never guaranteed in theory. Setting "root=/dev/mmcblk0p2" in /proc/cmdline has always caused the kernel to use the second partition from the SD card as the rootfs. The NXP development boards are typically shipped with either - LSDK, which uses "root=UUID=", or - OpenIL, which uses "root=/dev/mmcblkNp2" So for OpenIL, let's preserve that old behavior by adding some aliases which create naming consistency (for LSDK it doesn't matter): - the SD card controller uses /dev/mmcblk0 - the eMMC controller uses /dev/mmcblk1 For the Kontron SL28 boards, Michael Walle says that they are shipped with "root=UUID=" already, so the probing order doesn't matter, but it is more natural to him for /dev/mmcblk0 to be the eMMC, so let's do it the other way around there. The aliases are parsed by mmc_alloc_host() in drivers/mmc/core/host.c. Cc: Ashish Kumar <Ashish.Kumar@nxp.com> Cc: Yangbo Lu <yangbo.lu@nxp.com> Cc: Michael Walle <michael@walle.cc> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Michael Walle <michael@walle.cc> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.