Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 2 Mar 2018 17:11:17 +0100
From:   Thomas Petazzoni <thomas.petazzoni@bootlin.com>
To:     Antoine Tenart <antoine.tenart@bootlin.com>
Cc:     davem@davemloft.net, Yan Markman <ymarkman@marvell.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        maxime.chevallier@bootlin.com, gregory.clement@bootlin.com,
        miquel.raynal@bootlin.com, nadavh@marvell.com, stefanc@marvell.com,
        mw@semihalf.com
Subject: Re: [PATCH net-next 3/5] net: mvpp2: use a data size of 10kB for Tx
 FIFO on port 0
Message-ID: <20180302171117.2344a893@windsurf.lan>
In-Reply-To: <20180302154044.25204-4-antoine.tenart@bootlin.com>
References: <20180302154044.25204-1-antoine.tenart@bootlin.com>
        <20180302154044.25204-4-antoine.tenart@bootlin.com>
Organization: Bootlin (formerly Free Electrons)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hello,

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 ?

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 ?

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com