From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache Date: Mon, 18 Apr 2011 09:29:33 +0200 Message-ID: <201104180929.33569.arnd@arndb.de> References: <1302817968-28516-1-git-send-email-fernando.lugo@ti.com> <20110414223036.GA7335@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.8]:60266 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752495Ab1DRH3s (ORCPT ); Mon, 18 Apr 2011 03:29:48 -0400 In-Reply-To: <20110414223036.GA7335@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org 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, Ramesh Gupta , Hari Kanigeri On Friday 15 April 2011, 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. It's also completely upside-down: The iommu support should provide interfaces using the dma-mapping API, not use that API to provide a machine specific version of the generic interface. As far as I can tell, nothing actually uses these drivers, maybe we should just remove them before we get any code in the mainline kernel that depends on it. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Mon, 18 Apr 2011 09:29:33 +0200 Subject: [PATCH] OMAP: iommu flush page table entries from L1 and L2 cache In-Reply-To: <20110414223036.GA7335@n2100.arm.linux.org.uk> References: <1302817968-28516-1-git-send-email-fernando.lugo@ti.com> <20110414223036.GA7335@n2100.arm.linux.org.uk> Message-ID: <201104180929.33569.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 15 April 2011, 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. It's also completely upside-down: The iommu support should provide interfaces using the dma-mapping API, not use that API to provide a machine specific version of the generic interface. As far as I can tell, nothing actually uses these drivers, maybe we should just remove them before we get any code in the mainline kernel that depends on it. Arnd