From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Chulski Subject: RE: [PATCH net-next 3/5] net: mvpp2: use a data size of 10kB for Tx FIFO on port 0 Date: Sun, 4 Mar 2018 06:29:59 +0000 Message-ID: References: <20180302154044.25204-1-antoine.tenart@bootlin.com> <20180302154044.25204-4-antoine.tenart@bootlin.com> <20180302171117.2344a893@windsurf.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Cc: "davem@davemloft.net" , Yan Markman , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "maxime.chevallier@bootlin.com" , "gregory.clement@bootlin.com" , "miquel.raynal@bootlin.com" , Nadav Haklai , "mw@semihalf.com" To: Thomas Petazzoni , Antoine Tenart Return-path: In-Reply-To: <20180302171117.2344a893@windsurf.lan> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > On Fri, 2 Mar 2018 16:40:42 +0100, Antoine Tenart wrote: > > > -/* Initialize Tx FIFO's */ > > +/* Initialize Tx FIFO's > > + * The CP110's total tx-fifo size is 19kB. > > + * Use large-size 10kB for fast port but 3kB for others. > > + */ > > Is there a reason to hardcode 10KB for port 0, and 3KB for the other ports ? > Would there be use cases where the user may want different configurations > ? > Design requirement are 10KB TX FIFO for the 10Gb/sec and 2.5KB for the 2.5Gb/sec. Since only port 0 support 10Gb/sec and ports 1&2 support up to 2.5Gb/sec. I don't see any reason to change this configurations. Also TX FIFO size could be set only during probe. > It's just that it feels very "hardcoded" to enforce specifically those numbers. > > Also, does it make sense to mention the CP110 here ? Is this 19 KB limitation > a limit of the PPv2.2 IP, or of the CP110 ? PPv2.2 IP is part of 110 communication processor. Next communication processor will has different Packet processor or next generation of PPv2.x Limit is PPv2.2 TX FIFO. Stefan.