From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406AbdERWVs (ORCPT ); Thu, 18 May 2017 18:21:48 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:35404 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130AbdERWVq (ORCPT ); Thu, 18 May 2017 18:21:46 -0400 Subject: Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral To: Geert Uytterhoeven , Andrew Lunn Cc: Geert Uytterhoeven , Rob Herring , Frank Rowand , Thomas Petazzoni , Sergei Shtylyov , "netdev@vger.kernel.org" , "devicetree@vger.kernel.org" , Linux-Renesas , "linux-kernel@vger.kernel.org" References: <1495112345-24795-1-git-send-email-geert+renesas@glider.be> <20170518193453.GB13759@lunn.ch> From: Florian Fainelli Message-ID: <08a89dd5-b707-8b8f-b8e1-e20b9ed630b7@gmail.com> Date: Thu, 18 May 2017 15:21:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/18/2017 01:36 PM, Geert Uytterhoeven wrote: > Hi Andrew, > > On Thu, May 18, 2017 at 9:34 PM, Andrew Lunn wrote: >>>> This most certainly works fine in the simple case where you have one PHY >>>> hanging off the MDIO bus, now what happens if you have several? >>>> >>>> Presumably, the first PHY that returns EPROBE_DEFER will make the entire >>>> bus registration return EPROB_DEFER as well, and so on, and so forth, >>>> but I am not sure if we will be properly unwinding the successful >>>> registration of PHYs that either don't have an interrupt, or did not >>>> return EPROBE_DEFER. >>>> >>>> It should be possible to mimic this behavior by using the fixed PHY, and >>>> possibly the dsa_loop.c driver which would create 4 ports, expecting 4 >>>> fixed PHYs to be present. >>> >>> mdiobus_unregister(), called from of_mdiobus_register() on failure, >>> should do the unwinding, right? >>> >>> And when the driver is reprobed, all PHYs are reprobed, until they all >>> succeed. >> >> That is the theory. I looked at that while reviewing the patch. But >> this has probably not been tested in anger. It would be good to test >> this properly, with not just the first PHY returning -EPROBE_DEFER, to >> really test the unwind. > > Unfortunately I don't have a board with multiple PHYs, so I cannot test > that case. > > Does unbinding/rebinding a network driver with multiple PHYs currently > work? Or module unload/reload? Usually there is a strict 1:1 mapping between a network device (not driver) and a PHY device, switch drivers however, would have multiple PHYs (one per port, aka net_deice). NB: binding and unbinding of PHYs is pretty broken at the moment though, because there is a complete disconnect between what the Ethernet MAC expects, and the state in which the PHY is. I had some patches to fix that, but this turned out to be playing whack-a-mole which I typically suck at. -- Florian