From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Garry Subject: Re: [PATCH 01/23] devicetree: bindings: hisi_sas: add v2 HW bindings Date: Fri, 8 Jan 2016 15:34:37 +0000 Message-ID: <568FD70D.1090303@huawei.com> References: <1452262542-64589-1-git-send-email-john.garry@huawei.com> <1452262542-64589-2-git-send-email-john.garry@huawei.com> <20160108145256.GG3097@leverpostej> <568FD281.4050207@huawei.com> <20160108151934.GA32692@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160108151934.GA32692@leverpostej> Sender: linux-scsi-owner@vger.kernel.org To: Mark Rutland Cc: JBottomley@odin.com, martin.petersen@oracle.com, robh+dt@kernel.org, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, linuxarm@huawei.com, zhangfei.gao@linaro.org, xuwei5@hisilicon.com, john.garry2@mail.dcu.ie, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, arnd@arndb.de, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org >>>> +Optional main node properties: >>>> + - am-max-trans : limit controller for am max transmissions >>> >>> Is this a boolean? Number? >>> >> >> This is a boolean. It is for dealing with a quirk in the chipset: an >> instance of the controller in the hip06 chipset requires registers >> set with a different init value. > > Ok. I think the property at needs a better description for that. > > It's not clear to me how "limit controller for am max transmissions" > maps to writing a specific value to some registers, but I don't know > much about SAS. > > Is this some well-known thing, or values specific to hip06? > > Thanks, > Mark. > This is a specific issue for hip06 chipset. There is a bug in the HW on hip06 where controller #1 has to set to 2 registers to non-default values to limit "am-max-transmissions". This would not be a common SAS/SCSI controller property and is specific to our HW. Thanks, John