From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] [OneNAND] OTP support re-implementation 1/1 From: Artem Bityutskiy To: Amul Kumar Saha In-Reply-To: <6098B9D32DCD48C387EF96034FFFC55D@sisodomain.com> References: <87D6E94B11734CE1A253D9AE203F4192@sisodomain.com> <4A94CF0A.6060106@gmail.com> <6098B9D32DCD48C387EF96034FFFC55D@sisodomain.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 28 Aug 2009 16:38:56 +0300 Message-Id: <1251466736.3514.10.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: David Woodhouse , kyungmin.park@samsung.com, linux-mtd@lists.infradead.org Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2009-08-27 at 12:07 +0530, Amul Kumar Saha wrote: > >> Re-implemented OTP support for OneNAND > >> Added following features to OneNAND > >> 1. Lock only 1st Block in OneNAND > >> 2. Lock BOTH 1st Block and OTP Block in OneNAND > > > > -ENOPARSE > > > > Large patches like this normally require good explanations of what is > > done, why it is done, which problem it solves, how it is done, etc. > > > > What is OTP in OneNAND? > The device includes, > 1. one block-sized OTP (One Time Programmable) area and > 2. user-controlled 1st block OTP(Block 0) > that can be used to increase system security or to provide identification capabilities. > > What is done? > In OneNAND, one block of the NAND Array is set aside as an OTP memory area, and 1st Block (Block 0) > can be used as OTP area. > This area, available to the user, can be configured and locked with secured user information. > The OTP block can be read, programmed and locked using the same operations as any other NAND Flash > Array > memory block. After issuing an OTP-Lock, OTP block cannot be erased. OTP block is fully-guaranteed > to be a valid block. > > Why it is done? (Impact) > Locking the 1st Block OTP has the effect of a 'Write-protect' to guard against accidental > re-programming of data stored in the 1st block and OTP Block. > > Which problem it solves? > OTP support is provided in the existing implementation of OneNAND/Flex-OneNAND driver, but it is not > working with OneNAND devices. > Have observed the following in current OTP OneNAND Implmentation, > 1. DataSheet specific sequence to lock the OTP Area is not followed. > 2. Certain functions are quiet generic to cope with OTP specific activity. > This patch re-implements OTP support for OneNAND device. > > How it is done? > For all blocks, 8th word is available to the user. > However,in case of OTP Block, 8th word of sector 0, page 0 is reserved as OTP Locking Bit area. > Therefore, in case of OTP Block, user usage on this area is prohibited. > Condition specific values are entered in the 8th word, sector0, page 0 of the OTP block during the > process of issuing an OTP-Lock. > The possible conditions are:- > 1. Only 1st Block Lock > 2. Only OTP Block Lock > 3. Lock both the 1st Block and the OTP Block > > What feature additions have been done in this patch? > This patch adds feature for:- > 1. Only 1st Block Lock > 2. Lock both the 1st Block and the OTP Block Could you insert the description to the patch and re-send it, please? -- Best Regards, Artem Bityutskiy (Артём Битюцкий)