Re: [U-Boot] dtb vs. kernel command line arguments

Re: [U-Boot] dtb vs. kernel command line arguments

[Grant Likely]

On Mon, 4 Mar 2013 18:03:23 -0600, Kim Phillips <kim.phillips-KZfg59tc24xl57MIdRCFDg@public.gmane.org> wrote:
> On Mon, 4 Mar 2013 10:30:45 -0800
> Curt Brune <curt-qUQiAmfTcIp+XZJcv9eMoEEOCMrvLtNR@public.gmane.org> wrote:
> 
> > Hello -
> > 
> > I want to pass a number of arguments from u-boot to the booted kernel. 
> > The arguments are needed by user space applications, not the kernel.
> > 
> > I can think of two ways:
> > 
> > 1. append args by setting "bootargs".
> > 2. add nodes to the dtb before booting.
> > 
> > Is there a preferred way to pass information like this?
> > 
> > Like I said the arguments are not needed by the kernel device drivers, 
> > but by user space applications.
> > 
> > I like the structure of nodes in the dtb.
> 
> please don't dual-purpose device trees as a mechanism of getting
> arguments through the kernel into userspace - device trees strictly
> describe the hardware.

Why not? The chosen node in particular is for software configuration. I
don't have any problem with passing U-Boot extra data through the chosen
node. Just don't go crazy and please document it.

g.