From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Date: Tue, 30 Sep 2014 14:02:36 +0200 Subject: [U-Boot] [linux-sunxi] Re: [PATCH] sunxi: Fix gmac not working reliable on the Bananapi In-Reply-To: References: <1411928001-3455-1-git-send-email-hdegoede@redhat.com> <20140929091337.34888c61@i7> <20140929181635.GA4587@excalibur.cnev.de> Message-ID: <542A9BDC.2050600@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi, On 09/29/2014 08:35 PM, jonsmirl at gmail.com wrote: > On Mon, Sep 29, 2014 at 2:16 PM, Karsten Merker wrote: >> On Mon, Sep 29, 2014 at 09:13:37AM +0300, Siarhei Siamashka wrote: >>> How did you come to the idea to poke these bits? >> >> The linux 3.4 kernel from https://github.com/LeMaker/linux-bananapi >> (which is a patched linux-sunxi.org 3.4 kernel) does not show this >> problem, so we started looking into what is different there, and the >> relevant change that was found was setting these particular >> undocumented bits. > > File at issue here asking for the documentation > https://github.com/allwinner-zh/documents I'm already talking to Allwinner about this, it seems that bits 10-11, or more likely 10-12 of the gmac clk register are the tx equivalent of bits 5-7, "Configure GMAC receive clock delay chain". I think this is there to deal with the pcb data and clk traces not having the same length, so that this is highly board specific. I'm waiting on confirmation on this from Allwinner, as well as some info on the unit of this 0-7 value. Regards, Hans