From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753032AbcBVPUD (ORCPT ); Mon, 22 Feb 2016 10:20:03 -0500 Received: from mout.kundenserver.de ([212.227.126.135]:53144 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789AbcBVPT6 (ORCPT ); Mon, 22 Feb 2016 10:19:58 -0500 From: Arnd Bergmann To: Anurag Kumar Vulisha Cc: "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "tj@kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-ide@vger.kernel.org" , Anirudha Sarangi , Srikanth Vemula , Punnaiah Choudary Kalluri Subject: Re: [RFC PATCH] drivers: ata: Read Rx water mark value from device-tree Date: Mon, 22 Feb 2016 16:19:39 +0100 Message-ID: <18251200.Xfr10N5eWq@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <3802E9A6666DF54886E2B9CBF743BA9825E00BD4@XAP-PVEXMBX01.xlnx.xilinx.com> References: <1455974302-7082-1-git-send-email-anuragku@xilinx.com> <28916176.WDrPajhOPa@wuerfel> <3802E9A6666DF54886E2B9CBF743BA9825E00BD4@XAP-PVEXMBX01.xlnx.xilinx.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:kYdbHzVYFVv2LyifHvhdlu8qpv0B68ou041JrfOzgzgT4KjUkmA 2WYY/Fxs+s/KiDMoBFxBVLyvXdXYV0Wgp9ZvZVWmH2dqwMhTXc4YeBa5VYZdIxSu+WLJUH8 NATs9cm4q9gjnsoCJH0JDMM1r7J2vbuZba4IhhhyZdG4neeLTveDLEkQwHMiBboL2/4pbxV h2GhEgaW4FiiaSHNPkqdA== X-UI-Out-Filterresults: notjunk:1;V01:K0:H78avXlnXFY=:mS5/TAgURAyPgO6VIOlBRa 1hkVEBj0alQFsTs0Ypv+Dw/HoPaZ0TjcbnEYU57XmyT57QzqWjlCAv601RUNgTkAOI/2Mh/XO G/LcxIjMb3QOCY4GCYYKrRI9C0TkQ3JACFH+5jxgJDKxWCbcM7Hje2ksSulklmWJuh5MrQMQM 4l1AeC0XKbGyt9cTz29MZkWpBdQjARLdpScxBFYyxKw2EeHF0RHWaCHyVrgOBDmnkFX/jlq9s QVe3HxN0BXdSxqvRIm4UCXDhUa+JDXNVtvjx2Clv2bgPrwpsNlq2FV0vttKZ52pOF1fTUC88h eszRoQF0NHc1s1AfHBMqaExxH/oI6E9miCYFyvYeUoH0mxxovrxcoG8mgKFTjeu5EcLlmn2+C GWXmTz+r6hYxcst+90DVuBHLz24JL6zeXaz+3IhN7icjOuYIcIjRKGbWL9MG4otZRDVG9cBr7 T3b5t4zVO8iLk849rbTaVRxcO7jS4UkZURotnhP3cOPHRDRPV1lXTICdu186taeJgVLixN1sC vziRE/c1x28hb684aiHB+csafcP3ZvysqkaC+cSfpZY8bemclVx650xtga6+4yyi5qrjxmgGJ /G9DxS4JfN/IRDLD2svglQ5rNuz4SJB/EesyrK3l+FFX2yWHnEX7HXmblFvcTNjcc7K2afZVt 3sC4UVYcPJjLif7yGXMQs7K/lZEiiP+rquuVdz6wOg9nKqIT6f/GKLnn6018riGKiYTjVqydu I3qBy12K8WLhyk5X Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 22 February 2016 10:53:11 Anurag Kumar Vulisha wrote: > > > > > > > How would a hardware integrator know which value is right for a particular > > SoC? > > > > Could it be keyed off the hardware ID? Could the bootloader perhaps set an > > appropriate value in the AHCI_VEND_PTC register at boot time and the driver > > read the initial value from it? > > > > From the description, it sounds like this is a policy decision rather than > > hardware description, and shouldn't really be in here. > > > > Thanks for reviewing the patch. Can I use module_param() for this watermark instead of reading it from devicetree or > doing it in bootloader. In bootloader we are initializing serdes controller for high speed devices. As a part of this initialization > we will be reseting all the high speed pheripherals which are using serdes, so SATA will also get resetted. Because of this > reason, can I use module_param() for Rxwatermark value instead? > I don't know what is appropriate because I have no idea what Rxwatermark is good for. Can you try describing why we can't just set it to the correct value for everyone automatically? Arnd