From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 299C5C43215 for ; Thu, 28 Nov 2019 14:53:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01B7E21771 for ; Thu, 28 Nov 2019 14:53:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="ZipJOp8l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726835AbfK1Ow7 (ORCPT ); Thu, 28 Nov 2019 09:52:59 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:59364 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726446AbfK1Ow6 (ORCPT ); Thu, 28 Nov 2019 09:52:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=NGylHzPIXkw1Am/2gMfVIehuMuf/ARavlgeMprXQiyM=; b=ZipJOp8lAgpH5pTviCz7fzk2RK DI1N1nJ0H+/QgiAakL+FDA0Y8yfRfMRAdQFe66IW5z65HRJPWpyk99/Mc1oMXkutfrRcdXfiVOu4F BRRXVyFjqMvsYXfejCZtBzljGoNqRfwQBOw3VDCbdMzr0WSN1EPSd7hZhNM2+pptGbj8=; Received: from andrew by vps0.lunn.ch with local (Exim 4.92.2) (envelope-from ) id 1iaL9y-0003sE-VK; Thu, 28 Nov 2019 15:52:46 +0100 Date: Thu, 28 Nov 2019 15:52:46 +0100 From: Andrew Lunn To: Milind Parab Cc: "Nicolas.Ferre@microchip.com" , "antoine.tenart@bootlin.com" , "davem@davemloft.net" , "netdev@vger.kernel.org" , "f.fainelli@gmail.com" , "hkallweit1@gmail.com" , "linux-kernel@vger.kernel.org" , Dhananjay Vilasrao Kangude , Parshuram Raju Thombare , "rmk+kernel@arm.linux.org.uk" Subject: Re: [PATCH 2/3] net: macb: add support for C45 MDIO read/write Message-ID: <20191128145246.GD3420@lunn.ch> References: <1574759354-102696-1-git-send-email-mparab@cadence.com> <1574759389-103118-1-git-send-email-mparab@cadence.com> <20191126143717.GP6602@lunn.ch> <19694e5a-17df-608f-5db7-5da288e5e7cd@microchip.com> <20191127185129.GU6602@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > This patch doesn't affect current C22 operation of the driver. > However if a user selects C45 on incompatible MAC (there are old MAC, prior to Release1p10, released 10th April 2003) MDIO operations may fails. How do they fail? Lockup the chip and require a cold boot? Timeout after 10ms and return -ETIMEOUT? Currently, there is nothing stopping a C45 access to happen. There has been talk of making the probe for C45 PHYs the same as C22, scan the bus. I guess that would be implemented by adding a flag to each MDIO bus driver indicating it supports C45. All 32 addresses would then be probed using C45 as well as C22. So we need to be sure it is safe to use C45 on these older devices. Andrew