Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934992AbcLVKQH (ORCPT ); Thu, 22 Dec 2016 05:16:07 -0500 Received: from smtprelay.synopsys.com ([198.182.60.111]:50740 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761579AbcLVKQF (ORCPT ); Thu, 22 Dec 2016 05:16:05 -0500 Subject: Re: [PATCH] stmmac: CSR clock configuration fix To: David Miller , References: <6d4c6d15a60c93a8aef5e3e03b9cd64cdcf232c8.1482232420.git.jpinto@synopsys.com> <20161221.132104.1026207180067066991.davem@davemloft.net> CC: , , , , , From: Joao Pinto Message-ID: <41c56a6a-b7ce-6305-5dbb-02a023df5642@synopsys.com> Date: Thu, 22 Dec 2016 10:15:20 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20161221.132104.1026207180067066991.davem@davemloft.net> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.107.19.116] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1209 Lines: 35 ?s 6:21 PM de 12/21/2016, David Miller escreveu: > From: Joao Pinto > Date: Tue, 20 Dec 2016 11:21:47 +0000 > >> When testing stmmac with my QoS reference design I checked a problem in the >> CSR clock configuration that was impossibilitating the phy discovery, since >> every read operation returned 0x0000ffff. This patch fixes the issue. >> >> Signed-off-by: Joao Pinto > > This isn't enough. > > It looks like various parts of this driver set the mask field > differently. > > dwmac1000_core.c and dwmac100_core.c set the mask to be the low bits. > > But dwmac4_core.c uses GENMASK(11, 8) which means the mask is a value > which is shifted up already. > > So your patch will break chips driven by dwmac4_core.c. I am using a GMAC4 reference design to test the patches. The clock configuration as is, does not work, resulting in the phy discovery failure. By applying this patch I am able to set the clock value properly. I am going to check in the Databook of GMAC4 and older versions in order to justify better. > > In order for your change to be correct you must consolidate all of > these various pieces to use the same convention. > Thanks.