On 14/11/2012 11:29, Otavio Salvador wrote: > > Hi Otavio,
> > In the text you have the offset to save the image onto a NAND offset so > I fail to see how it'd be used for SD-Card. > > Can you elaborate it a bit? No, I can't without introducing errors. Current code supports Falcon only booting from NAND - I do not think that it is a big thing to use another media, but it is not yet done. This document must > +and can be generalized seen as a way to start an image performing > the minimum > +required initialization. SPL initializes mainly the RAM controller, > and after > +that copies U-Boot image into the memory. The "Falcon" mode extends > this way > +allowing to start the Linux kernel directly from SPL. A new command > is added > +to U-Boot to prepare the parameters that SPL must pass to the > kernel, using > +ATAGS or Device Tree. > + > +Falcon adds a command under U-Boot to reuse all code responsible to > prepare > +the interface with the kernel. In usual U-boot systems, these > parameters are > +generated each time before loading the kernel, passing to Linux the > address > +in memory where the parameters can be read. > +With falcon, this snapshot can be saved into persistent storage and > SPL is > +informed to load it before running the kernel. > > > You mix Falcon and falcon. You're right, there are already comments about this. This will be fixed globally in V3 (I will use Falcon Mode consistently). > I'd say you always use Falcon as it is the > name of the feature so it ought to be in upper case. Another thing, > 'With falcon, ' ought to be move to the previous line or have an empty > line before it. Ok > > > +To boot the kernel, these steps under a Falcon-aware U-Boot are > required: > + > +1. Boot the board into U-Boot. > +Use the "spl export" command to generate the kernel parameters area > or the DT. > +U-boot runs as when it boots the kernel, but stops before passing > the control > +to the kernel. > + > +2. Saves the prepared snapshot into persistent media. > +The address where to save it must be configured into board > configuration > +file (CONFIG_CMD_SPL_NAND_OFS for NAND). > > > And for others? Not yet implemented, patches welcome ! But you are right, there is already a patch to use a NOR flash that should flow soon into mainline. I will check and add documentation for it. For the orher media, the document must be updated together when they will be full supported. > > > +3. Boot the board into "Falcon" mode. SPL will load the kernel and copy > +the parameters area to the required address. > + > +It is required to implement a custom mechanism to select if SPL > loads U-Boot > +or another image. > +The value of a GPIO is a simple way to operate the selection, as > well as > +reading a character from the SPL console if CONFIG_SPL_CONSOLE is set. > > > An empty line before "The value"? Ok Best regards, Stefano Babic -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
