Re: getting allwinner SoC support upstream (was Re: Uploading linux (3.9.4-1))

[Stephen Warren <swarren@wwwdotorg.org>]

On 06/05/2013 02:46 PM, jonsmirl@gmail.com wrote:
> On Wed, Jun 5, 2013 at 3:46 PM, Luke Kenneth Casson Leighton
> <lkcl@lkcl.net <mailto:lkcl@lkcl.net>> wrote:
...
>     the detect line, which is the write-protect line, to setting the DRAM
>     clock timings, saying which kernel driver must be loaded to support
>     the touchscreen, enabling debugging, JTAG, naming the GPIOs for easy
>     and convenient use in the kernel code: basically there isn't a single
>     piece of hardware on the allwinner SoC family which *isn't*
>     reconfigureable through script.fex... and they've even integrated it
>     into u-boot *and* their low-level (early) bootloader as well [which
> 
> 
> Device tree support has been integrated into uboot for about five years now.

There are two aspects to DT support in U-Boot:

1) Having U-Boot pass a DT to the kernel, possibly manipulating a few
properties on the way, e.g. RAM size. As you say, this has been around a
while.

2) Having U-Boot itself read a DT and configure itself, just like the
kernel does. This is relatively new, and only supported by a few boards
(all Tegra to some extent, and a couple each Samsung Exynos and Xilinx
boards). I suspect/guess this is the kind of thing that Luke was
referring to re: U-Boot fex integration.