Re: Debian in a Pcduino3
On Tuesday 30 December 2014 15:36:34 Patrice Go wrote:
> It seems that dtb(s) is an electronic shema (in a file), for that the
> kernel recognize the board (partially or completely).
> Thanks for the explanation, it is more clear now.
>
> However, i don't know if the dtb (and others modifications to do) can be
> done just in reading the electronic shema... but if it is necessary to have
> the physical board to know more precisely some I/O address, i can give some
> informations (there's an installed OS - not the one i want- with a Shell in
> the pcduino3 board) from this one. If it can help for the next dtb.
All you need to do is find the file from the 3.17 or later kernel (it can be
found at kernel.org by looking at the git tree (I chose one from 3.18.1) at
(this next is only one line):-
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/arch/arm/boot/dts?id=v3.18.1
you will find a file called:-
sun7i-a20-pcduino3.dts
This file is specifically the one for the pcduino3 and defines everything that
the kernel needs to know to run on the pcduino3.
Then follow the instructions in:-
https://wiki.debian.org/InstallingDebianOn/Allwinner#Installing_on_systems_that_are_not_supported_out_of_the_box
David
>
> Is there a mean to know when the dtb and others spécifications, enabling
> the install in pcduino3, will be in jessie ? I don't know how to find this
> information and where are the diff from jessie enouncing that...
>
> Great thanks for this work in the pcduino3...
>
> Le 28 déc. 2014 01:20, "Karsten Merker" <merker@debian.org> a écrit :
> > On Sat, Dec 27, 2014 at 11:18:25PM +0100, Patrice Go wrote:
> >
> > [using a dtb from a newer kernel with kernel 3.16]
> >
> > > understood. don't have enough technical capacities and time to
> > > advance in that... is it something like that, that it would be
> > > necessary to do ? :
> > > http://olimex.wordpress.com/2013/09/18/7795/
> >
> > Hello,
> >
> > the olimex page describes something completely different - it is
> > about manually setting up a Debian rootfs with a linux-sunxi.org
> > 3.4 kernel. The linux-sunxi.org 3.4 kernel does not use
> > device-trees, but instead uses the Allwinner-specific fex
> > system, which is incompatible with mainline kernels.
> >
> > I guess you need some more background information about Linux on
> > arm-based systems:
> >
> > Historically, every arm-based system needed a specifically built
> > kernel. This obviously did not scale well to a large number of
> > systems, so people worked on a solution, which was found in the
> > form of device-trees. A device-tree is a description of the
> > hardware setup of a specific board. It contains information such
> > as which I/O-pins are connected to which external devices and
> > which non-probeable hardware components are built onto the board.
> > Systems-on-Chip ("SoC") like the Allwinner A20 give a hardware
> > designer the possibility to use their I/O connectors for very
> > different functions, which means that the very same I/O pin that
> > is used for detecting the presence of an SD card on one board
> > might be used to control the power supply of an ethernet PHY on
> > another board. All this information is encoded in the board's
> > device-tree, so that a single kernel which understands this
> > device-tree information can run on lots of different boards, as
> > long as a device-tree for that board exists and the kernel has
> > the necessary drivers for the hardware components on the board.
> >
> > The kernel 3.16 in Jessie has drivers for several core components
> > of the pcduino3 (like serial port, MMC controller, USB host
> > controller, internal ethernet MAC, external ethernet PHY, SATA
> > controller), but due to lack of a device-tree for the board, it
> > does not "know" how several of the connectors or external
> > components are wired to the SoC. If one provides the device-tree
> > information for the board (which can be taken from kernel 3.17)
> > to kernel 3.16, those drivers which are already available in
> > kernel 3.16 can make use of it and thereby work on the "new"
> > board.
> >
> > I hope this helps a bit in clearing up the confusion.
> >
> > Regards,
> > Karsten
> > --
> > Gem. Par. 28 Abs. 4 Bundesdatenschutzgesetz widerspreche ich der Nutzung
> > sowie der Weitergabe meiner personenbezogenen Daten für Zwecke der
> > Werbung sowie der Markt- oder Meinungsforschung.
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