From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753244AbbBRVIi (ORCPT ); Wed, 18 Feb 2015 16:08:38 -0500 Received: from mail-we0-f182.google.com ([74.125.82.182]:36073 "EHLO mail-we0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751973AbbBRVIg (ORCPT ); Wed, 18 Feb 2015 16:08:36 -0500 Date: Wed, 18 Feb 2015 22:08:30 +0100 From: Richard Cochran To: Stathis Voukelatos Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, netdev@vger.kernel.org, abrestic@chromium.org Subject: Re: [PATCH v2 0/3] net: Linn Ethernet Packet Sniffer driver Message-ID: <20150218210830.GA7778@localhost.localdomain> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 17, 2015 at 02:03:30PM +0000, Stathis Voukelatos wrote: > The command string for packet matching is stored in module RAM > and consists of a sequence of 16-bit entries. Each entry includes > an 8-bit command code and and 8-bit data value. Valid command > codes are: > 0 - Don't care > 1 - Match: packet data must match command string byte > 2 - Copy: packet data will be copied to FIFO > 3 - Match/Stamp: if packet data matches string byte, a timestamp > is copied into the FIFO > 4 - Copy/Done: packet data will be copied into the FIFO. > This command terminates the command string. Why do you need to expose this interface to user space at all? Why not just time stamp every frame? How does the "Match" command work? The frame must have one particular byte? That can't be right. Please explain. Thanks, Richard