Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756102Ab0BAUOL (ORCPT ); Mon, 1 Feb 2010 15:14:11 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:42677 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756063Ab0BAUOJ (ORCPT ); Mon, 1 Feb 2010 15:14:09 -0500 Date: Mon, 1 Feb 2010 15:14:04 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Catalin Marinas cc: Matthew Dharm , Sergei Shtylyov , Ming Lei , , linux-kernel , Sebastian Siewior , Greg KH Subject: Re: USB mass storage and ARM cache coherency In-Reply-To: <1265045354.25750.52.camel@pc1117.cambridge.arm.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1332 Lines: 30 On Mon, 1 Feb 2010, Catalin Marinas wrote: > On Fri, 2010-01-29 at 18:54 +0000, Matthew Dharm wrote: > > HOWEVER, I firmly believe that the cache-management functions belong with > > the driver that actually talks to the low-level hardware, as that's the > > only place where you can be 100% certain of what cache operations are > > needed. After all, I think someone is working on a USB-over-IP transport, > > and trying to manage cache at the usb-storage level in that scenario is > > just silly. > > > > So, let's put this in the HCD drivers and be done with it. > > The patch below is what fixes the I-D cache incoherency issues on ARM. I > don't particularly like the solution but it seems to be the only one > available. > > IMHO, Linux should have functions similar to the DMA API but for PIO > drivers (e.g. pio_map_single/pio_unmap_single) that non-coherent > architectures can define, otherwise being no-ops. Any thoughts? You should bring this up on the linux-arm-kernel mailing list and CC: the ARM maintainer. They are the ones most directly affected. Alan Stern -- 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/