From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.230] helo=mgw-mx03.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1LuRMs-0003Q1-Qk for linux-mtd@lists.infradead.org; Thu, 16 Apr 2009 13:11:10 +0000 Subject: Re: [PATCH 0/3 v3] mtd: physmap_of: Add multiple regions and concatenation support From: Artem Bityutskiy To: Stefan Roese In-Reply-To: <200904161452.25393.sr@denx.de> References: <200904161405.04100.sr@denx.de> <1239884344.3390.213.camel@localhost.localdomain> <200904161452.25393.sr@denx.de> Content-Type: text/plain; charset="UTF-8" Date: Thu, 16 Apr 2009 16:09:24 +0300 Message-Id: <1239887364.3390.215.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: Grant Likely , linuxppc-dev@ozlabs.org, devicetree-discuss , linux-mtd@lists.infradead.org Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2009-04-16 at 14:52 +0200, Stefan Roese wrote: > On Thursday 16 April 2009, Artem Bityutskiy wrote: > > On Thu, 2009-04-16 at 14:05 +0200, Stefan Roese wrote: > > > This patchset adds support to handle multiple non-identical chips in one > > > flash device tree node. It also adds concat support to physmap_of. This > > > makes it possible to support e.g. the Intel P30 48F4400 chip which > > > internally consists of 2 non-identical NOR chips on one die. Additionally > > > partitions now can span over multiple chips: > > > > > > mtd: physmap_of: Add multiple regions and concatenation support > > > mtd/powerpc: Factor out MTD physmap bindings into mtd-physmap.txt > > > mtd/powerpc: Describe multiple "reg" tuples usage > > > > > > v2 addresses all comments from Grant Likely, including factoring out the > > > MTD dts bindings documentation into a separate file. > > > > > > v3 addresses all comments (again from Grant). > > > > Sorry for my ignorance, but could you please explain why regions > > exists as an MTD concept? Why different regions could not be > > represented as different MTD devices? The benefit is - simplicity. > > The result of these multiple "reg" tuples *is* multiple MTD devices. Not sure > if this explains your comment/question. Please let me know if you still have > some comments. OK, I was confused. In MTD there is a weird notion of "region". See 'struct mtd_info': /* Data for variable erase regions. If numeraseregions is zero, * it means that the whole device has erasesize as given above. */ int numeraseregions; struct mtd_erase_region_info *eraseregions; in include/linux/mtd/mtd.h I thought you use that, and wanted to realize why is that "region" notion needed. -- Best regards, Artem Bityutskiy (Битюцкий Артём)