From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH net-next v4 1/2] dts: Add a binding for Synopsys emac max-frame-size Date: Thu, 16 Jan 2014 19:00:45 +0000 Message-ID: <1389898845.11912.66.camel@bwh-desktop.uk.level5networks.com> References: <1389881155-9758-1-git-send-email-vbridgers2013@gmail.com> <1389881155-9758-2-git-send-email-vbridgers2013@gmail.com> <1389894601.11912.54.camel@bwh-desktop.uk.level5networks.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , , Giuseppe CAVALLARO , , , , , Kumar Gala , Dinh Nguyen , "Rayagond Kokatanur" To: Vince Bridgers Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:27901 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750764AbaAPTAu (ORCPT ); Thu, 16 Jan 2014 14:00:50 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2014-01-16 at 12:48 -0600, Vince Bridgers wrote: > On Thu, Jan 16, 2014 at 11:50 AM, Ben Hutchings > wrote: > > On Thu, 2014-01-16 at 08:05 -0600, Vince Bridgers wrote: > >> This change adds a parameter for the Synopsys 10/100/1000 > >> stmmac Ethernet driver to configure the maximum frame > >> size supported by the EMAC driver. Synopsys allows the FIFO > >> sizes to be configured when the cores are built for a particular > >> device, but do not provide a way for the driver to read > >> information from the device about the maximum MTU size > >> supported as limited by the device's FIFO size. > >> > >> Signed-off-by: Vince Bridgers > >> --- > >> V4: add comments to explain use of max-frame-size with respect > >> to inconsistent definition and use in the ePAPR v1.1 spec > > > > Well, ePAPR does not seem to be consistent with itself. :-) > > > >> V3: change snps,max-frame-size to max-frame-size > >> V2: change snps,max-mtu to snps,max-frame-size > >> --- > >> Documentation/devicetree/bindings/net/stmmac.txt | 13 ++++++++++++- > >> 1 file changed, 12 insertions(+), 1 deletion(-) > >> > >> diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt > >> index eba0e5e..d553be2 100644 > >> --- a/Documentation/devicetree/bindings/net/stmmac.txt > >> +++ b/Documentation/devicetree/bindings/net/stmmac.txt > >> @@ -29,7 +29,17 @@ Required properties: > >> ignored if force_thresh_dma_mode is set. > >> > >> Optional properties: > >> -- mac-address: 6 bytes, mac address > >> +- mac-address: 6 bytes, mac address > >> +- max-frame-size: Maximum frame size permitted. This parameter is useful > >> + since different implementations of the Synopsys MAC may > >> + have different FIFO sizes depending on the selections > >> + made in Synopsys Core Consultant. Note that the usage > >> + is inconsistent with the definition in the ePAPR v1.1 > >> + specification, as it defines max-frame-size inclusive > >> + of the MAC DA, SA, Ethertype and CRC while usage is > >> + consistent with the IEEE definition of MAC Client > >> + Data, which is sans the MAC DA, SA, Ethertype and > >> + CRC. > > [...] > > > > While this is very precise, I fear that it is now so verbose that it > > actually becomes confusing. Can this not be condensed to 'the maximum > > MTU and MRU, rather than the maximum Ethernet frame size'? > > > > Ben. > > Sure, I'll cut this down and resubmit as V5. How about > > "The Maximum Transfer Unit (IEEE defined MTU), rather than the maximum > frame size." Sounds good. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.