From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Date: Tue, 08 Jul 2008 11:05:10 -0500 Subject: [U-Boot-Users] [PATCH, resend] Support dynamic/patched NAND ENV offset In-Reply-To: <20080708000912.GC25698@prithivi.gnumonks.org> References: <20080706162812.GC20299@prithivi.gnumonks.org> <20080707184724.GE17430@loki.buserror.net> <20080708000912.GC25698@prithivi.gnumonks.org> Message-ID: <48739036.2080806@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Harald Welte wrote: > On Mon, Jul 07, 2008 at 01:47:24PM -0500, Scott Wood wrote: >> It works if you allow room for bad blocks within each partition, and treat >> the environment as its own partition. Current u-boot supports skipping bad >> blocks within a desginated environment region. > > which wastes a lot of space, if you have something like a 128kByte > erase-block-size (like most 2kByte page size NAND's today)... so if you > want to have redundancy and use some spare blocks you will end up with > something on the order of 512kByte of wasted flash space to store a > couple of hundreds of bytes environment. Not very elegant. > > Furthermore, if you want to make sure it always works with any of your > components that are within the spec of the manufacturer, then you will > waste even more. The problem is that a new virgin component e.g. a > 64MByte flash from Samsung can have already as many as 1.3MBytes of bad > blocks. Fair enough... > Therefore, I still believe that such a feature is useful and should be > merged into u-boot. If there are problems with my particular > implementation, I'm happy to address them. Can you base it off of the testing branch of the u-boot-nand-flash repo? > I also have another patchset for what I call 'dynpart' support, i.e. the > dynamic calculation of a unit-specific partition table that ensures the > net size of partitions are as per spec, no matter how many of the > factory default blocks are located where. So it would even support > NAND devices with a worse spec than the ones that we were using. Interesting... Would such a patch eliminate the need for this one, by making the environment a dynamic partition? Is there any (plan for) Linux support? -Scott