[U-Boot] [RFC/PATCH] davinci: disable dcache on boards with EMAC

[Christian Riesch]

Wolfgang,

On Mon, Nov 28, 2011 at 4:59 PM, Wolfgang Denk <wd at denx.de> wrote:
> Dear Christian Riesch,
>
> In message <CABkLOboon_r_xwZOriHBhnNRM4+jFYKVKqDVToih6CvCKxs0zA at mail.gmail.com> you wrote:
> ...
>> Then I commented out the lines
>> #define CONFIG_SYS_ICACHE_OFF
>> #define CONFIG_SYS_DCACHE_OFF
>> #define CONFIG_SYS_L2CACHE_OFF
>> re-built u-boot and tried the same, the Ethernet connection still
>> worked and I could still load the kernel image.
>
> What does the "dc" command print in your configuration?

U-Boot > dc
Unknown command 'dc' - try 'help'

;-)

After rebuilding with #define CONFIG_CMD_CACHE I get

U-Boot > dc
Data writethrough) Cache is OFF

no matter whether the #define CONFIG_SYS_xxCACHE_OFF lines are in the
config file or not.

If the CONFIG_SYS_xxxCACHE_OFF lines are commented out, I can enable
d-cache with the dcache on command and then Ethernet access fails,
e.g., ping runs into timeout.

U-Boot > ping 10.0.0.5
Using DaVinci-EMAC device
host 10.0.0.5 is alive
U-Boot > dcache on
Data (writethrough) Cache is ON
U-Boot > ping 10.0.0.5
Using DaVinci-EMAC device
ping failed; host 10.0.0.5 is not alive

Regards, Christian