| Message ID | 1469882593-21604-1-git-send-email-hdegoede@redhat.com |
|---|---|
| State | Accepted |
| Commit | 3f8ea3b06eaf7c9e2456058bcbde32461e73aeb7 |
| Delegated to: | Hans de Goede |
| Headers | show |
On Sat, 2016-07-30 at 14:43 +0200, Hans de Goede 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 the crc32 of words 1 - 3 to get a > more unique value for the mac-address / serialnr. > > Cc: Chen-Yu Tsai <wens@csie.org> > Cc: Corentin LABBE <clabbe.montjoie@gmail.com> > Cc: Amit Singh Tomar <amittomer25@gmail.com> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Ian Campbell <ijc@hellion.org.uk> Two minor thoughts: At some point it might be nice to switch from using sid[3] as the temporary variable to contain the csum since it is no longer the 3rd element of the sid in any meaningful way. If you decide to do so for a v4, then please do keep my ack from above. Likewise if you decide to express the big chain of ifndef's via Kconfig instead, you can keep the ack. Ian.
diff --git a/board/sunxi/board.c b/board/sunxi/board.c index ef3fe26..209fb1c 100644 --- a/board/sunxi/board.c +++ b/board/sunxi/board.c @@ -27,6 +27,7 @@ #endif #include <asm/gpio.h> #include <asm/io.h> +#include <crc.h> #include <environment.h> #include <libfdt.h> #include <nand.h> @@ -622,7 +623,24 @@ static void setup_environment(const void *fdt) int i, ret; ret = sunxi_get_sid(sid); - if (ret == 0 && sid[0] != 0 && sid[3] != 0) { + if (ret == 0 && sid[0] != 0) { + /* + * The single words 1 - 3 of the SID have quite a few bits + * which are the same on many models, so we take a crc32 + * of all 3 words, to get a more unique value. + * + * Note we only do this on newer SoCs as we cannot change + * the algorithm on older SoCs since those have been using + * fixed mac-addresses based on only using word 3 for a + * long time and changing a fixed mac-address with an + * u-boot update is not good. + */ +#if !defined(CONFIG_MACH_SUN4I) && !defined(CONFIG_MACH_SUN5I) && \ + !defined(CONFIG_MACH_SUN6I) && !defined(CONFIG_MACH_SUN7I) && \ + !defined(CONFIG_MACH_SUN8I_A23) && !defined(CONFIG_MACH_SUN8I_A33) + sid[3] = crc32(0, (unsigned char *)&sid[1], 12); +#endif + /* Ensure the NIC specific bytes of the mac are not all 0 */ if ((sid[3] & 0xffffff) == 0) sid[3] |= 0x800000;
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 the crc32 of words 1 - 3 to get a more unique value for the mac-address / serialnr. Cc: Chen-Yu Tsai <wens@csie.org> Cc: Corentin LABBE <clabbe.montjoie@gmail.com> Cc: Amit Singh Tomar <amittomer25@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- Changes in v3: -Use crc32 instead of ex-or-ing the bytes together -Use new algorithm on all newer SoCs -Only check for sid[0] != 0 to capture non initialized sid-s. Changes in v2: -ex-or all 3 words together instead of picking a different word --- board/sunxi/board.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)