From mboxrd@z Thu Jan  1 00:00:00 1970
From: olof@lixom.net (Olof Johansson)
Date: Sun, 20 Nov 2011 16:49:30 -0800
Subject: [PATCH v1] dts: tegra-ventana: use proper root instead of /dev/ram
In-Reply-To: <74CDBE0F657A3D45AFBB94109FB122FF1740805E1B@HQMAIL01.nvidia.com>
References: <1321338087-3662-1-git-send-email-vwadekar@nvidia.com>
 <74CDBE0F657A3D45AFBB94109FB122FF1740805E1B@HQMAIL01.nvidia.com>
Message-ID: <20111121004930.GA17338@quad.lixom.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Nov 15, 2011 at 11:16:51AM -0800, Stephen Warren wrote:
> Varun Wadekar wrote at Monday, November 14, 2011 11:21 PM:
> > From: Pritesh Raithatha <praithatha@nvidia.com>
> > 
> > The root file system on ventana resides on /dev/mmcblk0p1.
> 
> Well, that's entirely up to however the user set up their system, although
> I admit mmcblk0p1 is likely to be the common case; I certainly carry
> basically this patch locally for many boards.
> 
> > Update the dts file to use the proper root instead of /dev/ram.
> > 
> > Signed-off-by: Pritesh Raithatha <praithatha@nvidia.com>
> > Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
> 
> Acked-by: Stephen Warren <swarren@nvidia.com>
> 
> Of course, perhaps an even better solution is to just remove /chosen from
> all the board .dts files, and stop using CONFIG_APPENDED_DTB since U-boot
> supports FDT, and will update the cmdline with whatever the user chose.
> Still, I think this is probably OK for now.

Actually, removing the default root path is probably a better idea, since it
will vary from installation to installation and doesn't make sense to hard
code.

There's two ways to solve this with u-boot:

* Boot with an u-boot that knows how to pass a device tree (and add the
  bootargs to it before launching the kernel, and do so by either booting
  a fitImage or by loading the device tree explicitly.

* Use the appended-dtb kernel format, and select the ARM_ATAG_DTB_COMPAT
  option. That will mean that the bootargs passed in from atags are moved over
  to the device tree.

So, I would rather see a patch removing the root= argument alltogether.


Thanks!

-Olof