From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751577AbdFHXTA (ORCPT ); Thu, 8 Jun 2017 19:19:00 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:34488 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751554AbdFHXS6 (ORCPT ); Thu, 8 Jun 2017 19:18:58 -0400 Date: Thu, 8 Jun 2017 16:18:54 -0700 From: Brian Norris To: Chris Packham Cc: Boris Brezillon , "dwmw2@infradead.org" , "andrew@lunn.ch" , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Marek Vasut , Richard Weinberger , Cyrille Pitchen Subject: Re: [PATCH 3/4] mtd: mchp23k256: add partitioning support Message-ID: <20170608231854.GF102137@google.com> References: <20170517053908.26138-1-chris.packham@alliedtelesis.co.nz> <20170517053908.26138-4-chris.packham@alliedtelesis.co.nz> <20170517172911.5f926712@bbrezillon> <20170601184340.GA102137@google.com> <20170601222320.GE102137@google.com> <92ffaa3cef7d49aeb9d5abae06e10ddb@svr-chch-ex1.atlnz.lc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <92ffaa3cef7d49aeb9d5abae06e10ddb@svr-chch-ex1.atlnz.lc> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 01, 2017 at 11:08:08PM +0000, Chris Packham wrote: > Do we need a flag to indicate SRAM-like properties? I assume there is a > difference between NO_ERASE on ROM devices where there is just no way of > erasing the data. For {S,F,M}RAM there is no block erase operation but I think we already have that: #define MTD_CAP_ROM 0 #define MTD_CAP_RAM (MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE) The key signifier for ROM would be !MTD_WRITEABLE. > you can overwrite data to destroy it (which is actually my use-case with > this SPI SRAM). I was tempted to set erase_size = 1 at one point which > in my mind was technically accurate but would probably upset the mtd > layer just as much as 0. I'm not sure what erasesize should be here. I suppose 0, but really, I think the MTD_NO_ERASE flag is the clearer indication that erase is not needed, and that one should ignore the erasesize. Brian