On Fri, 8 Nov 2019 at 19:48, Palmer Dabbelt <pal...@dabbelt.com> wrote: > > The device tree format allows for arrays of strings, which are encoded > with '\0's inside regular strings. These are ugly to represent in C, so > the helper function represents them as strings with internal '\0's that > are terminated with a double '\0'. In other words, the array > ["string1", "string2"] is represeted as "string1\0string2\0". > > The DTB generated by this function is accepted by DTC and produces an > array of strings, but I can't find any explicit line in the DT > specification that defines how these are encoded.
> +/* > + * This uses a particularly odd encoding: "strings" is a list of strings that > + * must be terminated by two back-to-back '\0' characters. > + */ > +int qemu_fdt_setprop_strings(void *fdt, const char *node_path, > + const char *property, const char *strings); The clean API for this would be to use varargs so you could write qemu_fdt_setprop_stringlist(fdt, node, prop, "arm,armv8-timer", "arm,armv7-timer"); and have it do the assembly into the encoding that fdt expects. That would require us to do a bit of allocation-and-freeing to assemble the string, of course, but then we only do fdt creation at startup. NB: I think that this is a good idea but not-for-4.2 material, so if you wanted your sifive board change to go into 4.2 you should probably start with the simple approach and leave the refactoring for the next release cycle. thanks -- PMM