From mboxrd@z Thu Jan 1 00:00:00 1970 From: viresh kumar Subject: Re: [PATCH V2 2/2] pata_arasan_cf: Adding support for arasan compact flash host controller Date: Tue, 22 Feb 2011 11:16:56 +0530 Message-ID: <4D634DD0.60106@st.com> References: <20110218143438.GK21209@htj.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from eu1sys200aog112.obsmtp.com ([207.126.144.133]:35496 "EHLO eu1sys200aog112.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751766Ab1BVFrc (ORCPT ); Tue, 22 Feb 2011 00:47:32 -0500 In-Reply-To: <20110218143438.GK21209@htj.dyndns.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: "jgarzik@pobox.com" , "linux-ide@vger.kernel.org" , "viresh.linux@gmail.com" , Shiraz HASHIM , Armando VISCONTI , amitgoel On 02/18/2011 08:04 PM, Tejun Heo wrote: > On Fri, Feb 18, 2011 at 05:10:14PM +0530, Viresh Kumar wrote: >> > +static struct scsi_host_template arasan_cf_sht = { >> > + ATA_PIO_SHT(DRIVER_NAME), >> > +}; > Hmmm... You probably have different requirements for .sg_tablesize and > .dma_boundary, likely to be more lax. > Tejun, Actually, we really don't have scatter-gather in our controller. We have to read/write to the same FIFO address for every 512 bytes, after which we get buf_avail interrupt. And Controller can do a maximum transfer of 256 KB after which it gives transfer complete interrupt. So all sg has to be handled in software, framework or driver. Also, we will always read/write from/to FIFO. And the external DMA controller doesn't have any limitation of this dma_boudary. So i feel i should keep .sg_tablesize = SG_ALL, .dma_boundary = 0xFFFFFFFF, Please correct me if i am wrong. -- viresh