From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [63.81.120.155] (helo=imap.sh.mvista.com) by canuck.infradead.org with esmtp (Exim 4.62 #1 (Red Hat Linux)) id 1GBxVZ-0001mO-0D for linux-mtd@lists.infradead.org; Sat, 12 Aug 2006 13:42:51 -0400 Message-ID: <44DE1357.5010703@ru.mvista.com> Date: Sat, 12 Aug 2006 21:43:51 +0400 From: Sergei Shtylyov MIME-Version: 1.0 To: Milton Miller Subject: Re: [RFC] Adding MTD to device tree References: <311553550076b8b45674.846930886.miltonm@bga.com> In-Reply-To: <311553550076b8b45674.846930886.miltonm@bga.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: linuxppc-dev@ozlabs.org, linux-mtd@lists.infradead.org, arnd@arndb.de, linuxppc-embedded@ozlabs.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello. Milton Miller wrote: >>>+ h) MTD nodes >>>+ >>>+ Memory Technology Devices are flash, ROM, and similar chips, often used >>>+ for solid state file systems on embedded devices. >>>+ >>>+ Required properties: >>>+ >>>+ - device_type : has to be "mtd" >>>+ - compatible : Should be the name of the MTD driver. Currently, this is >>>+ most likely to be "physmap". >>>+ - reg : Offset and length of the register set for the device. >>I would prefer to call them something different in the device tree. >>The name 'mtd' is very specific to Linux, but the device tree >>is a more generic concept. "Memory type devices" are specific to Linux? Doubt it. :-) In fact, device type "flash" sounds too restrictive. >>I understand that the booting-without-of.txt file is by definition >>Linux specific as well, but we should be prepared for making parts >>of it a OS independent binding at the point where we put the same >>device nodes into actual OF implementations that able to boot >>different operating systems. >>I would prefer a naming that has >> Required properties: >> - device_type : one of "nand-flash", "nor-flash", or "rom". >> - model : an identifier for the actual controller chip used. >> - compatible : Should be the name of the MTD driver. For >> type "rom", this is most likely "physmap". > I'm with your suggestion for device_type and model, but not > compatable. "physmap"? What kind of device is that? A Directly mapped NOR flash or ROM I think. > command set name, maybe with a width, would be That'd be pretty useless if you don't let Linux know which MTD *map* driver to use. And I have specified the "bank-width" prop. > appropriate. Physmap is the name of another linux driver. And the role of the "compatible" prop is exactly to help OS in selecting the driver. > Something like direct or linear might be appropriate for a rom, > where just address and length appear. I agree that "linear" or "direct" may be better variants. > Even rom would be better than physmap. Doubt it since the ROM is the only one thing (and even the least probable) that we're going to support. > milton WBR, Sergei