[PATCH 1/3] riscv: Do not return error if reserved node already exists

[Atish Patra]

On Tue, Jun 23, 2020 at 12:24 AM Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Hi Atish,
>
> On Fri, Jun 19, 2020 at 9:52 AM Atish Patra <atish.patra at wdc.com> wrote:
> >
> > Not all errors are fatal. If a reserved memory node already exists in the
> > destination device tree, we can continue to boot without failing.
> >
> > Signed-off-by: Atish Patra <atish.patra at wdc.com>
> > ---
> >  arch/riscv/lib/fdt_fixup.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/lib/fdt_fixup.c b/arch/riscv/lib/fdt_fixup.c
> > index 6db48ad04a56..91524d9a5ae9 100644
> > --- a/arch/riscv/lib/fdt_fixup.c
> > +++ b/arch/riscv/lib/fdt_fixup.c
> > @@ -62,7 +62,7 @@ int riscv_fdt_copy_resv_mem_node(const void *src, void *dst)
> >                 pmp_mem.end = addr + size - 1;
> >                 err = fdtdec_add_reserved_memory(dst, basename, &pmp_mem,
> >                                                  &phandle);
> > -               if (err < 0) {
> > +               if (err < 0 && err != FDT_ERR_EXISTS) {
>
> This FDT_ERR_EXISTS error code is possibly returned by:
>
>     node = fdt_add_subnode(blob, parent, name);
>     if (node < 0)
>         return node;
>
> But if it exists, I believe fdtdec_add_reserved_memory() already
> returns 0 because they are likely to have the same range of memory
> block start address and size, no?
>

Currently, yes. As libfdt and fdtdec_add_reserved_memory external to
this code, functionality
can change without modifying fdt_fixup.c knowingly or unknowingly.
FDT_ERR_EXISTS is harmless error in this context and we shouldn't
cause boot failure because of that.
That's why I add that exclusion.

> >                         printf("failed to add reserved memory: %d\n", err);
> >                         return err;
> >                 }
> > --
>
> Regards,
> Bin



-- 
Regards,
Atish