From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 15 Jun 2007 14:14:23 +1000 From: David Gibson To: Segher Boessenkool Subject: Re: [PATCH] powerpc: Create "rom" (MTD) device prpmc2800 Message-ID: <20070615041423.GB30104@localhost.localdomain> References: <4662EAA9.70104@ru.mvista.com> <466308F4.8050004@ru.mvista.com> <8ac5664208e0f59329b62ac2138bbc8c@kernel.crashing.org> <466312C2.4090200@ru.mvista.com> <548a7e11ffb577f6395b8f5a9c2fba2d@kernel.crashing.org> <466323EF.5040807@ru.mvista.com> <1181228442.2785.60.camel@pmac.infradead.org> <18fbfbaf113ab76b602d279848d9b405@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <18fbfbaf113ab76b602d279848d9b405@kernel.crashing.org> Cc: linuxppc-dev@ozlabs.org, David Woodhouse , Milton Miller , linux-mtd@lists.infradead.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Jun 07, 2007 at 05:55:44PM +0200, Segher Boessenkool wrote: > > Any representation of flash devices in the device-tree should ideally > > have 'bus width' and 'interleave' properties to contain this > > information. > > > > The 'bus width' cannot necessarily be inferred, especially where a > > given > > bus can be configured to allow multiple sizes of access. It's purely a > > function of how the flash chips are wired up. That's why we actually > > call it 'bank width', not 'bus width' in the Linux code. > > Ah, "bank width" as in "bus width" per chip select. I see. > > So I think the best thing to have would be > > compatible "cfi-flash" > bank-width like you said > device-width width of a single flash device > reg complete address range of this thing > > and then the Linux OF CFI flash code / MTD code just keeps > on probing devices from that address range until it has it > filled. > > Sounds good / comments / anything I missed? Slight revision suggestion. Can we make 'device-width' optional, with the default value being equal to the bank-width? -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson