From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1949197AbcBTWfF (ORCPT ); Sat, 20 Feb 2016 17:35:05 -0500 Received: from mout.kundenserver.de ([212.227.126.135]:65352 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1947774AbcBTWfC (ORCPT ); Sat, 20 Feb 2016 17:35:02 -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, anirudh@xilinx.com, svemula@xilinx.com, punnaia@xilinx.com, Anurag Kumar Vulisha Subject: Re: [RFC PATCH] drivers: ata: Read Rx water mark value from device-tree Date: Sat, 20 Feb 2016 23:34:41 +0100 Message-ID: <28916176.WDrPajhOPa@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1455974302-7082-1-git-send-email-anuragku@xilinx.com> References: <1455974302-7082-1-git-send-email-anuragku@xilinx.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:Rk6nGHVE+l2DZcjPR1ZrMgPTCyhhBRXAGnPtZJ1RNp1RdM6OYkj xmvFpBeQPZQxgctqnXW1rsr2zInAOm+bCtqO4DtrViwPqXnv+iF3nyMlX98er2spWSI24U6 wQ9u0dRekOZ/lt4sjkJoupeG1/0XZrecqCr6NikTgRSPlF+UCMcfLkZwNgTvn/y1zRVbvTK F4PeYPxrnj+ADj1YYpdew== X-UI-Out-Filterresults: notjunk:1;V01:K0:Cl6XbujVNEQ=:qhQenpxdZlGwp/QgIQH0GY A1LYqkpKshwlBBdE/nj2LmtBoai9t+YfkEQcdZA5zX7VtyJS/nOgjFAuf/Xn3LUrxwFqfiebd 2zYTzwchAlzKatUirLAg31RUxsN7GKBZum9knul+LSKTgXhP3qjcw/QijDwaksGad6kASTPVk BLDhCbJYrizxRMt5eWNoyCc1X6p+xp1lze0ilgdh+Q9STzFEP4OyhDuYep7RtrpltHkCDJ8wR qF+5u0OdLO8nLCGgX3dgYv7S3pcfdCSbB6DArALi732hxuSMCX6Qr+HjT+wZCQ4LwOD9s/Q2O Ajt5TUhV+qzKkc94qY8/wYYyY2HXVAwQej57LhJeSMCX18ATDqxudfsQqXYhjfimuEK7eofoH kSOfSHMLXtVzLcub8ED2xp3IP8Vs6Xnn0HDiA21Pcgq/7D0dMUd2p2W6wmBHmetSaXGQU1Jxs du6LILoFGNHqU5HS8uqfN+pKmFdYebtvKnkIdF05ctNjrVCoUwzhUmIf6rCxNEaKOdfgQOvG4 7knvIvKO4rWKju0oPcahku7f0joMmXbCp/fbrovTeynLRNty2dISyzNjDiwvZ2NaEO0rYJbjs b3SI++3SrO1PXXBE6VQBO1ki5WydUvPGj87Axs3YiR3tlUzI8UCZn+9aFBrnXeNcIhY+HrQZC jmnpSGgzsiG27rkVCwKwKOYX1q9gSrcoX9m12sTt1qfsvCykCiKSfYmRwNx044Qd69N2LtgMr F2Mw13jbpC9t50J/ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 20 February 2016 18:48:22 Anurag Kumar Vulisha wrote: > index 7ca8b97..7e48dfc 100644 > --- a/Documentation/devicetree/bindings/ata/ahci-ceva.txt > +++ b/Documentation/devicetree/bindings/ata/ahci-ceva.txt > @@ -8,6 +8,7 @@ Required properties: > > Optional properties: > - ceva,broken-gen2: limit to gen1 speed instead of gen2. > + - ceva,rx-watermark: RX fifo water mark level for SATA controller. > > Examples: > ahci@fd0c0000 { > @@ -17,4 +18,5 @@ Examples: > interrupts = <0 133 4>; > clocks = <&clkc SATA_CLK_ID>; > ceva,broken-gen2; > + ceva,rx-watermark = <0x40>; > }; > 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. Arnd