From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Date: Thu, 18 May 2006 00:48:57 +0200 Subject: [U-Boot-Users] Booting from NAND Flash Problems In-Reply-To: Your message of "Wed, 17 May 2006 11:32:08 PDT." <4436349.post@talk.nabble.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de In message <4436349.post@talk.nabble.com> you wrote: > > This means that a small program has to run first. This small program is < > 16K in size and copies U-Boot from Nand Flash into RAM and then executes it. > > In theory this should work fine. This works fine in practice for a couple of systems. > However i am having loads of issues with running u-boot with cache enabled. > If cache is enabled then the Nand Driver (I am using the latest Linux MTD > based driver) > has problems as it uses a DMA copy to copy to the Nand Flash. > If I implement cache flushing I break u-boot. Then your port of U-Boot is broken. > I was wondering if anyone has any hints or tips on how u-boot is used in a > system with only Nand Flash and a Mips processor. I don;t see anything in your setup where using NAND flash or a MIPS CPU plays a role; all this is pretty similar on all architectures. > I have seen other posts suggesting mips processors should run uncached but > this is obviously slower. Define "run uncached". > Has the case been consider where relocation is not necessary i.e a small Yes. > program just loads the executable to a location and runs it. I know > relocation can save memory but in my system it means extra copying and > currently extra headaches!! Then don't do it. And BTW: Relocation does not save memory at all. Best regards, Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de The ultimate barrier is one's viewpoint. - Terry Pratchett, _The Dark Side of the Sun_