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| author | Sascha Hauer <s.hauer@pengutronix.de> | 2016-04-29 10:53:51 +0200 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2016-05-04 11:58:46 +0200 |
| commit | f66990af3cf2e1bfda60938beeadcb98557d9487 (patch) | |
| tree | 1396f22e661ba9d8fe12ba89922b73f6ec372484 /Documentation/user/booting-linux.rst | |
| parent | a9b18674c0ffefd08064dff898b1f621f8c258d5 (diff) | |
| download | barebox-f66990af3cf2e1bfda60938beeadcb98557d9487.tar.gz barebox-f66990af3cf2e1bfda60938beeadcb98557d9487.tar.xz | |
bootm: Optionally add a root= option to Kernel command line
It becomes a common case that the Kernel is loaded from the filesystem
which later becomes the rootfs. This adds a possibility to let bootm
automatically append the root= option to the kernel command line. This
is done when global.bootm.appendroot is true.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'Documentation/user/booting-linux.rst')
| -rw-r--r-- | Documentation/user/booting-linux.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/user/booting-linux.rst b/Documentation/user/booting-linux.rst index 98628faf9d..f26299efd9 100644 --- a/Documentation/user/booting-linux.rst +++ b/Documentation/user/booting-linux.rst @@ -99,6 +99,20 @@ with addpart to the Kernel: Kernel command line: mtdparts=physmap-flash.0:512k(bootloader),512k(env),4M(kernel),-(root); mxc_nand:1M(bootloader),1M(env),4M(kernel),-(root) +Creating root= options for the Kernel +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +It's a common case that the Linux Kernel is loaded from a filesystem +that later becomes the root filesystem for the Kernel. For several +filesystems barebox can automatically append a suitable root= option +to the Kernel command line. This is done when ``global.bootm.appendroot`` +is true. How the root= option is appended depends on the device type +and filesystem the kernel is booted from. For disk like devices (SD/MMC, +ATA) the partition UUID will be used, the root= option will be something +like ``root=PARTUUID=deadbeef-1``. For UBIFS fileystems it will be +``root=ubi0:volname ubi.mtd=mtdpartname rootfstype=ubifs``. NFS +filesystems will result in ``root=/dev/nfs nfsroot=ip:/path/to/nfsroot,v3,tcp``. +The ``v3,tcp`` part is configurable in ``global.linux.rootnfsopts``. The boot command ---------------- |