From mboxrd@z Thu Jan 1 00:00:00 1970 From: Franck Jullien Subject: Re: [PATCH] drivers/of: add option to load a default Device Tree Date: Thu, 30 Jun 2016 22:44:18 +0200 Message-ID: References: <1466607954-2821-1-git-send-email-franck.jullien@odyssee-systemes.fr> <57755ACF.1090204@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <57755ACF.1090204-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Frank Rowand Cc: Franck Jullien , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , jose.abreu-HKixBCOQz3hWk0Htik3J/w@public.gmane.org, Pantelis Antoniou , Lars-Peter Clausen List-Id: devicetree@vger.kernel.org 2016-06-30 19:45 GMT+02:00 Frank Rowand : > Hi Franck, > > (This could be confusing, with Franck and Frank -- feel free to > address me as rowand in this thread if it is less confusing.) > > On 06/22/16 08:05, Franck Jullien wrote: >> Even if a platform doesn't use a device tree during its >> boot process it can be useful to enable CONFIG_OF and get >> an empty device tree. >> >> Then, devices can use device tree overlays to populate this >> default tree. >> >> Signed-off-by: Franck Jullien >> --- >> drivers/of/Kconfig | 9 +++++++++ >> drivers/of/Makefile | 3 +++ >> drivers/of/base.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ >> drivers/of/default.dts | 4 ++++ >> drivers/of/unittest.c | 33 +++++---------------------------- >> include/linux/of.h | 2 ++ >> 6 files changed, 73 insertions(+), 28 deletions(-) >> create mode 100644 drivers/of/default.dts > > < snip > > > For context, in a later reply, you mention that this is for x86_64. > > My current inclination is to prefer not to solve the problem this way. > I was going to ask why you didn't just add the compiled default.dts > to the kernel as an appended device tree blob, until I found out > this was for x86_64. > > Can you add unflatten_devicetree() to x86_64, then just use the > appended device tree blob method? > You're saying I should implement the ability for x86_64 to detect and load a devicetree that is appended to the binary image like ARM does [1] ? Would you keep CONFIG_DEFAULT_DTB at all ? Or appending an empty (or not) devicetree would be after the binary image is built ? I like the idea. I think I could remove CONFIG_DEFAULT_DTB and let the user append a blob to the image. By the way, why having an empty devicetree built-in is not your preferred choice ? Franck. [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e2a6a3aafa9862c4a4b59f2a59b8f923d64a680e -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html