Hi Hannes,
On Tue, Sep 6, 2016 at 3:23 PM, Hannes Schmelzer Hannes.Schmelzer@br-automation.com wrote:
Bin Meng bmeng.cn@gmail.com schrieb am 06.09.2016 09:07:39:
[...]
Why is this needed? The MAC address is supposed to be programmed in the driver's probe routine.
For example on my custom ZYNQ board. The Ethernetcontroller within the ZYNQ has no ROM to store his own MAC-Address, further no MAC is stored within environment. So Ethernet gets probed with a "random MAC-Address" if configured.
Later somebody (like me) oder something (my bootscript) runs "setenv ethaddr ...." on the console. Result is (was before this patch), that all networking infrastructre
is
running this new mac, but hardware is running the old (random) one and networking is simple not functional.
This indicates that your ethernet driver does not program the latest MAC address everyone when it gets probed. The driver should be fixed.
The driver doesn't get probed again if mac-address is changed using "setenv ethaddr", so it has no chance to program anything.
Yes, driver is not probed when "setenv ethaddr", but next time when you type any ethernet related command (like tftpboot), the driver will be probed.
For program i understand, in this case with zynq, overtaking mac-address into his registers. There is per default no ROM to store some mac.
I have feeling that for some ethernet controllers, simply calling eth_write_hwaddr() may not change its MAC address correctly. It may need some special programming sequence like firstly turn off, reset, then program the MAC.
Regards, Bin