From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCHv2 00/10] Add memory mapped support for ti qspi, m25p80 serial flash. Date: Tue, 10 Dec 2013 19:34:01 +0100 Message-ID: <201312101934.01300.marex@denx.de> References: <1386339891-32717-1-git-send-email-sourav.poddar@ti.com> <201312101922.10618.marex@denx.de> <20131210182904.GG11468@sirena.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-out.m-online.net ([212.18.0.10]:56887 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752305Ab3LJSmb (ORCPT ); Tue, 10 Dec 2013 13:42:31 -0500 In-Reply-To: <20131210182904.GG11468@sirena.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Mark Brown Cc: Sourav Poddar , linux-spi@vger.kernel.org, computersforpeace@gmail.com, dwmw2@infradead.org, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, bcousson@baylibre.com, balbi@ti.com On Tuesday, December 10, 2013 at 07:29:04 PM, Mark Brown wrote: > On Tue, Dec 10, 2013 at 07:22:10PM +0100, Marek Vasut wrote: > > On Tuesday, December 10, 2013 at 05:11:43 PM, Mark Brown wrote: > > > There is some stuff that pushes up into the controller in that while > > > the device is in memory mapped mode as far as I can tell it's not safe > > > to do other accesses so if someone's put more than one device on the > > > SPI bus we need to handle interactions there. > > > > OK, so it's either-or . That seems OK, you might want to have two drivers > > for this ip block, one to handle it as a SPI block and one to handle it > > as a SPI-NOR block. ... that is of course, if these two modes can't work > > together. > > Or the client disables the memory map when it's not actively being used > and the stops other transfers starting while the mapping is in place. > I'd expect we'll have to cope with shared use at some point, hardware > engineers will probably build such systems. Aren't we fixing the problem at the wrong place ? Maybe it's about time to fix the engineers ;-) Best regards, Marek Vasut