On Fri, Feb 23, 2024 at 03:41:40PM +1100, David Gibson wrote:
> On Thu, Feb 22, 2024 at 10:38:54AM +0100, Uwe Kleine-König wrote:
> > On Thu, Feb 22, 2024 at 05:32:10PM +1100, David Gibson wrote:
> > > And here you can use fdt32_st() on (tree_val + poffset), avoiding
> > > quite some complexity.
> > 
> > There is some complexity because tree_val is a const char * (as this is
> > what fdt_getprop() returns) and fdt32_st() obviously doens't take a
> > const pointer.
> 
> Ah, right.  You can use fdt_getprop_w() to get a writable pointer
> instead.  If there was a way to have fdt_getprop() return a const
> pointer only if the fdt pointer it was given was const, I'd do that.

Look at how container_of_const() is defined in the kernel[1], this
requires C11 though. See
https://en.cppreference.com/w/c/language/generic for some docs.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/container_of.h?h=v6.7#n32
 
> > If you want to play around with that, the code is mostly a copy of
> > overlay_update_local_node_references() which could benefit from your
> > suggestions in the same way.
> 
> That's quite plausible.
> 
> > Can I lure you in improving overlay_update_local_node_references()? Then
> 
> Fair point..
> 
> https://github.com/dgibson/dtc/commit/24f60011fd43683d8e3916435c4c726e9baac9c9

I gave feedback on that one. Looks good.

> > I could copy from the improved function for my patch. (Or maybe refactor
> > the function to take a function as parameter which is
> 
> Eh... I'd prefer to avoid higher order functions in something this low
> level.

OK.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |