Re: [PATCH] fix #51791 - bug? mac 00:00:00:00:00:00 with natsemi DP83815 after driver load

[David Miller <davem@davemloft.net>]

From: "Roland Kletzing" <devzero@web.de>
Date: Mon, 17 Nov 2014 01:17:47 +0100

> This one should fix Bugzilla #51791 (details below). 
> 
> Natsemi driver does not read MAC correctly from eeprom, while natsemi-diag from nictools-pci does. Apparently, tt`s a timing issue in the kernel driver.
> 
> According to ftp://ftp.gwdg.de/pub/linux/misc/donald.becker/diag/natsemi-diag.c , eeprom_delay(ee_addr) is defined as follows:
> 
> /* Delay between EEPROM clock transitions.
>    This flushes the write buffer to prevent quick double-writes.
> */
> #define eeprom_delay(ee_addr) 	inl(ee_addr); inl(ee_addr)
> 
> while in the natsemi linux kernel driver, the delay is done this way :
> 
> #define eeprom_delay(ee_addr)   readl(ee_addr)
> 
> , which results in the MAC being all zero`s.
> 
> So i simply added a second readl() to increase delay (instead of turning into inl() as proposed before). This may look a little bit ugly, but it`s fixing the problem for me.
> 
> I´m not sure how many natsemi users being left on this planet (probably few), but i guess this change does not do any harm on platforms where the driver does not behave buggy, so please consider adding it to mainline/stable/longterm.
> 
> Signed-off-by: Roland Kletzing <devzero@web.de>

Please post your patch as a clean new email, without quoting things
after your signoff etc.

Also, please break your lines up to 80 columns max.

Thanks.