On Fri, 29 Jul 2016 11:49:45 +0200 Hans de Goede <hdego...@redhat.com> wrote:
> It seems that bytes 13-14 of the SID / bytes 1-2 from word 3 of the SID > are always 0 on H3 making it a poor candidate to use as source for the > serialnr / mac-address, and the other non constant words (1 and 2) also > have quite a few bits which are the same for some boards, > > This commits switches to using words 1 - 3 ex-or-ed together to get a > more unique value for the mac-address / serialnr. > > Cc: Chen-Yu Tsai <w...@csie.org> > Cc: Corentin LABBE <clabbe.montj...@gmail.com> > Cc: Amit Singh Tomar <amittome...@gmail.com> > Signed-off-by: Hans de Goede <hdego...@redhat.com> > --- > Changes in v2: > -ex-or all 3 words together instead of picking a different word > --- > board/sunxi/board.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/board/sunxi/board.c b/board/sunxi/board.c > index ef3fe26..e0734fb 100644 > --- a/board/sunxi/board.c > +++ b/board/sunxi/board.c > @@ -623,6 +623,21 @@ static void setup_environment(const void *fdt) > > ret = sunxi_get_sid(sid); > if (ret == 0 && sid[0] != 0 && sid[3] != 0) { > +#ifdef CONFIG_MACH_SUN8I_H3 > + /* > + * The single words 1 - 3 of the SID have quite a few bits > + * which are the same on many models on the H3, so we ex-or > + * them together to get a bit more unique value. > + * > + * Note we only do this on the H3 as we cannot change the > + * algorithm on other SoCs since those have been using > + * fixed mac-addresses based on only using word 3 for a > + * a long time and changing a fixed mac-address with an > + * u-boot update is not good. > + */ > + sid[3] ^= sid[1] ^ sid[2]; > +#endif > + > /* Ensure the NIC specific bytes of the mac are not all 0 */ > if ((sid[3] & 0xffffff) == 0) > sid[3] |= 0x800000; Using XOR is not a good idea, see my reply in the v1 patch discussion: http://lists.denx.de/pipermail/u-boot/2016-July/262298.html -- Best regards, Siarhei Siamashka _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot