[U-Boot] [PATCH V3 0/8] SPL Linux boot

[Andreas Bießmann]

Dear Wolfgang,

Am 26.08.2011 13:36, schrieb Wolfgang Denk:
> Dear Simon,
> 
> In message <4E563136.2030608 at gmail.com> you wrote:
>>
>>> A question ex ante: what is the "bp" in "savebp" supposed to mean? I
> ...
>> It means "save boot parameters" - better proposals welcome.

<snip>

> Also, I think we should try and make the approach a bit more generic.
> Your current implementation supports only NAND as storage.  But what
> if we want to do the same when booting from SDCard?
> 
> Maybe we should split the steps of extracting the FDT and ATAGS images
> and the process of actually writing them to persistent storage in two
> separate steps - for the second step we can then use existing standard
> commands, so only the "export" step is needed.

Well the 'export' step can already be done by exiting commands. e.g.

bootm start
bootm loados
bootm ramdisk (if CONFIG_SYS_BOOT_RAMDISK_HIGH)
bootm fdt (if CONFIG_OF_LIBFDT)
bootm cmdline
bootm bdt
bootm prep

Now the required date is ready to use at gd->bd->bi_boot_params, this
information should the board maintainer/user know as (for arm boards) it
is always set in board_init().

The data can now be written with already available commands regardless
whether they are nand or nor or fat/ext/ubi... write commands.

All this could be done in a new command or one can utilize a self
written script ...

The main parts of Simon's series are 'gather boot information' (make it
possible for arm), 'safe boot information' (the question discussed in
this mail' and 'use spl to start linux'. In my opinion (with knowledge
of his bachelor thesis filing date) the parts 'gather boot information'
and 'use spl to start linux' are most important cause the part 'safe
boot information' can currently be done with existing commands.

> As all this is about preparing for a SPL boot, I suggest we name the
> new command "spl"; the resulting user interface could be like this:
> 
> 
> 	spl export <img> addr [args ...]
> 
> with "img" being either "fdt" or "atags". [This would allow to add
> other SPL related commands easily in case we should need them.

Nevertheless +1 for spl in the new command name (only export as
suggested by Aneesh) is a bit weak.

best regards

Andreas Bießmann