On Thu, Feb 22, 2024 at 05:32:10PM +1100, David Gibson wrote:
> On Fri, Feb 16, 2024 at 07:19:20PM +0100, Uwe Kleine-König wrote:
> > +static int overlay_update_node_conflicting_references(void *fdto, int tree_node,
> > + int fixup_node,
> > + uint32_t fdt_phandle,
> > + uint32_t fdto_phandle)
> > +{
> > + int fixup_prop;
> > + int fixup_child;
> > + int ret;
> > +
> > + fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
> > +
> > + const fdt32_t *fixup_val;
> > + const char *tree_val;
> > + const char *name;
> > + int fixup_len;
> > + int tree_len;
> > + int i;
> > +
> > + fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
> > + &name, &fixup_len);
> > + if (!fixup_val)
> > + return fixup_len;
> > +
> > + if (fixup_len % sizeof(uint32_t))
> > + return -FDT_ERR_BADOVERLAY;
> > + fixup_len /= sizeof(uint32_t);
> > +
> > + tree_val = fdt_getprop(fdto, tree_node, name, &tree_len);
> > + if (!tree_val) {
> > + if (tree_len == -FDT_ERR_NOTFOUND)
> > + return -FDT_ERR_BADOVERLAY;
> > +
> > + return tree_len;
> > + }
> > +
> > + for (i = 0; i < fixup_len; i++) {
> > + fdt32_t adj_val;
> > + uint32_t poffset;
> > +
> > + poffset = fdt32_to_cpu(fixup_val[i]);
>
> You can use fdt32_ld_() here to slightly simplify this
I don't see what you suggest here. fixup_val is assigned to in
fdt_getprop_by_offset() which I need to get fixup_len and then fixup_val
is already around. If you still think this could be improved, please be
more explicit.
> > +
> > + /*
> > + * phandles to fixup can be unaligned.
> > + *
> > + * Use a memcpy for the architectures that do
> > + * not support unaligned accesses.
> > + */
> > + memcpy(&adj_val, tree_val + poffset, sizeof(adj_val));
>
> And here you can use fdt32_ld() which has unaligned access handling
> built in.
>
> > +
> > + if (fdt32_to_cpu(adj_val) == fdto_phandle) {
> > +
> > + adj_val = cpu_to_fdt32(fdt_phandle);
> > +
> > + ret = fdt_setprop_inplace_namelen_partial(fdto,
> > + tree_node,
> > + name,
> > + strlen(name),
> > + poffset,
> > + &adj_val,
> > + sizeof(adj_val));
> > + if (ret == -FDT_ERR_NOSPACE)
> > + return -FDT_ERR_BADOVERLAY;
> > +
> > + if (ret)
> > + return ret;
>
> 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.
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.
Can I lure you in improving overlay_update_local_node_references()? Then
I could copy from the improved function for my patch. (Or maybe refactor
the function to take a function as parameter which is
uint32_t delta;
uint32_t increase_by_delta(uint32_t phandle)
{
return phandle + delta;
}
for the overlay_update_local_node_references() case and
uint32_t fdt_phandle;
uint32_t fdto_phandle;
uint32_t resolve_fdt_conflict(uint32_t phandle)
{
if (phandle == fdto_phandle)
return fdt_phandle;
else
return phandle;
}
for my function (maybe passing the data stored in global vars here in a
context parameter).
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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