[PATCH v3 2/3] ARM: shmobile: Koelsch: add Ether support

[Geert Uytterhoeven]

Hi Sergei,

On Sun, Dec 8, 2013 at 9:52 PM, Sergei Shtylyov
<sergei.shtylyov at cogentembedded.com> wrote:
> Register Ether platform device and pin data on  the  Koelsch board.
> Register platform fixup for Micrel KSZ8041 PHY, just like on the Lager board.
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov at cogentembedded.com>

> --- renesas.orig/arch/arm/mach-shmobile/board-koelsch.c
> +++ renesas/arch/arm/mach-shmobile/board-koelsch.c

> +/* Ether */
> +static const struct sh_eth_plat_data ether_pdata __initconst = {
> +       .phy                    = 0x1,
> +       .edmac_endian           = EDMAC_LITTLE_ENDIAN,
> +       .phy_interface          = PHY_INTERFACE_MODE_RMII,
> +       .ether_link_active_low  = 1,
> +};

With the above, NFS root is terrible slow, and ping indicates more than
10% packet loss. I was trying to debootstrap Debian jessie, but gave up
after a few hours.

Based on earlier discussions I found in the mailing list archives, I
replaced the
".ether_link_active_low = 1" by ".no_ether_link = 1", and the problem went away.
Debootstrap completed in about one hour.  No more noticable packet loss
during normal operation.
I do still get "net eth0: Receive FIFO Overflow" once in a while, though (e.g.
when running nuttcp).

# nuttcp -r amd64box
  112.8022 MB /  10.14 sec =   93.3131 Mbps 2 %TX 15 %RX 0 retrans 0.28 msRTT
# nuttcp -t amd64box
   94.1981 MB /  10.04 sec =   78.7000 Mbps 3 %TX 5 %RX 0 retrans

With ".ether_link_active_low = 1", performance is halved:

# nuttcp -r amd64box
   56.0736 MB /  10.11 sec =   46.5290 Mbps 0 %TX 8 %RX 0 retrans 996.39 msRTT
# nuttcp -t amd64box
   47.7191 MB /  10.03 sec =   39.8991 Mbps 1 %TX 2 %RX 0 retrans

BTW, I'm using renesas-devel-v3.13-rc2-20131205, with the following 4 patches
from you applied on top:
      sh_eth: add R8A7791 support
      ARM: shmobile: r8a7791: add Ether clock
      ARM: shmobile: Koelsch: add Ether support
      ARM: shmobile: Koelsch: enable Ether in defconfig
Anything I'm missing?

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds