From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Tue, 26 Apr 2016 08:05:55 +0200 Subject: [U-Boot] RFC: i.MX6 write U-Boot to NAND In-Reply-To: <571F0001.8080504@denx.de> References: <571F0001.8080504@denx.de> Message-ID: <571F0543.1000807@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Sergey, Hi Heiko, On 26.04.2016 07:43, Heiko Schocher wrote: > add Stefano to Cc as he is the imx6 custodian, > > Am 25.04.2016 um 22:29 schrieb Sergey Kubushyn: >> Hi everybody, >> >> It looks like using kobs-ng utility is the only way to make a bootable >> NAND >> for i.MX6 and their siblings. There might be other utilities I'm not >> aware >> of but that doesn't change anything -- you need Linux (or whatever that >> utility runs on) running on your board to create and write all those >> FCB and >> other parts onto a virgin raw NAND device. > > Yes, I stumbled over that too recently ... > >> This makes initial programming a cumbersome and complicated operation. >> One >> can not program NAND on a development machine as it is easy to do with >> e.g. >> SD Card -- the OS must run on the same board where that NAND is >> because NAND >> is not removable. >> >> It is possible, of course, to assemble something on an SD Card and use >> that >> to program NAND but that assumes there is an SD Card slot on a target >> system >> and some means to tell it to boot off of SD Card. However it is not >> always a >> case -- there might be boards with NAND as only storage device available. >> That leaves only Serial/USB boot as only options for initial boot on a >> virgin board. However it does not provide means for writing the NAND >> U-Boot >> into actual NAND. >> >> There are many different varieties of NAND chips so those FCB and other >> structures are not generic i.e. they can not be defined beforehead and >> just >> prepended to the actual U-Boot image. Even if we have made those a >> configuration parameters there are still bad block tables that are chip >> specific so they should be discovered first i.e. FCB should be built >> dynamically based on NAND scanning results. >> >> Sure, one can write a custom first stage SPL that would've booted the >> actual >> U-Boot via the same Serial/USB interface and run it but then what? Let's >> assume the target board doesn't have ethernet so it would make it >> impossible >> to mount rootfs over NFS and no other storage devices available. It is >> still >> possible to load Linux kernel and bare minimal rootfs in initramfs >> image but >> that's a lot of serial downloading just for initializing NAND... >> >> It would be nice to have a U-Boot command that would've allowed >> initial NAND >> setup and writing NAND U-Boot image to it properly updating the headers. > > Yes, that would be great! > >> There might be other ways to do this that I might've overlooked... >> >> Does anybody knows a ready-made solution or works on something >> suitable for >> this purpose? I don't want to re-invent the wheel starting my own >> solution >> so it would've been good to hear from other guys who might've solved this >> dilemma. > > Sorry, I do not know another way. > >> Any thoughts? > > I think, an U-Boot command which writes the headers into the nand would > be a good thing. > > tools/imximage.c is may the wrong place, as the infos in FCB and DBBT > are dependend on the boards nand. I've missed such a tool a few years ago while porting U-Boot & Linux to a i.MX6 based NAND booting board as well. And noticed since then that barebox has included such a tool: http://lists.infradead.org/pipermail/barebox/2014-March/018202.html Perhaps its not too much work to port this tool over to U-Boot? Just an idea... Thanks, Stefan