Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754639Ab1D1QsS (ORCPT ); Thu, 28 Apr 2011 12:48:18 -0400 Received: from na3sys009aog111.obsmtp.com ([74.125.149.205]:39763 "EHLO na3sys009aog111.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751872Ab1D1QsR convert rfc822-to-8bit (ORCPT ); Thu, 28 Apr 2011 12:48:17 -0400 MIME-Version: 1.0 In-Reply-To: <20110428134055.GA19709@n2100.arm.linux.org.uk> References: <1302817968-28516-1-git-send-email-fernando.lugo@ti.com> <20110414223036.GA7335@n2100.arm.linux.org.uk> <20110428134055.GA19709@n2100.arm.linux.org.uk> Date: Thu, 28 Apr 2011 11:48:15 -0500 Message-ID: Subject: Re: [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache From: "Gupta, Ramesh" To: Russell King - ARM Linux Cc: Fernando Guzman Lugo , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tony@atomide.com, Hari Kanigeri Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1910 Lines: 44 Hi Russel, On Thu, Apr 28, 2011 at 8:40 AM, Russell King - ARM Linux wrote: > On Fri, Apr 15, 2011 at 06:26:40AM -0500, Gupta, Ramesh wrote: >> Russell, >> >> On Thu, Apr 14, 2011 at 5:30 PM, Russell King - ARM Linux >> wrote: >> > On Thu, Apr 14, 2011 at 04:52:48PM -0500, Fernando Guzman Lugo wrote: >> >> From: Ramesh Gupta >> >> >> >> This patch is to flush the iommu page table entries from L1 and L2 >> >> caches using dma_map_single. This also simplifies the implementation >> >> by removing the functions ?flush_iopgd_range/flush_iopte_range. >> > >> > No. ?This usage is just wrong. ?If you're going to use the DMA API then >> > unmap it, otherwise the DMA API debugging will go awol. >> > >> >> Thank you for the comments, this particular memory is always a write >> from the A9 for MMU programming and >> only read from the slave processor, that is the reason for not calling >> the unmap. I can re-look into the changes to call >> unmap in a proper way as this impacts the DMA API. >> Are there any other ways to perform only flush the memory from L1/L2 caches? > > We _could_ invent a new API to deal with this, which is probably going > to be far better in the longer term for page table based iommus. ?That's > going to need some thought - eg, do we need to pass a struct device > argument for the iommu cache flushing so we know whether we need to flush > or not (eg, if we have cache coherent iommus)... I agree with you, right now these functions are taking only start and end arguments but we can pass a struct deivice to these functions. thank you and regards Ramesh Gupta G -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/