On Mon, 30 May 2016 17:24:16 +0200
Boris Brezillon <boris.brezil...@free-electrons.com> wrote:
> Hi Hans,
>
> On Mon, 30 May 2016 17:12:53 +0200
> Boris Brezillon <boris.brezil...@free-electrons.com> wrote:
>
> > Generating raw NAND images is particularly useful for boot0 images
> > creation since the mainline driver is not supporting the funky layout
> > used by Allwinner's ROM code to load the boot0 binary from NAND.
> >
> > This tools also allows one to generate raw images for 'normal' partitions
> > so that they can be flashed before soldering on the NAND on the board
> > (using a regular NAND programmer).
> >
> > The tool takes care of generating ECC bytes and randomizing data as
> > expected by the NAND controller, and re-arranging the ECC/data sections
> > correctly.
>
> Don't know how you want to proceed regarding NAND SPL image creation in
> u-boot. We could either copy the sunxi-nand-image-builder sources in
> u-boot or provide a macro to pass the sunxi-tools binaries path
> (SUNXI_TOOLS_PATH?) and force the user to have the sunxi-tools
> installed on his build platform.
>
> Note that we'll need extra padding/concatenation steps to build an SPL
> image suitable for MLC NANDs.
Hi,
I guess, it is not a big secret that I'm also working on the SPI flash
boot support at the moment. And some information about the progress is
available here:
https://linux-sunxi.org/Bootable_SPI_flash
IMHO one of the most important requirements is to ensure that the device
can be always unbricked by the end users in a very simple way. That's
why I have added the SPI flash programming feature to the sunxi-fel
tool and it is available in a wip branch since about a week ago:
https://github.com/ssvb/sunxi-tools/commits/20160523-spiflash-wip
There is still some work left to do. For example, just having SPI
flash read/write functionality (which already works btw) is not
good enough because it is not sufficiently foolproof. There will
be a dedicated high level "spiflash-program" commmand to flash
the standard "u-boot-sunxi-with-spl.bin" file generated by U-Boot.
We had discussed this a bit on the IRC earlier:
http://irclog.whitequark.org/linux-sunxi/2016-05-13#16443894;
The sunxi-fel flasher tool can modify the u-boot-sunxi-with-spl.bin
image to automatically add some redundancy (two copies of the SPL):
https://linux-sunxi.org/Bootable_SPI_flash#Reliability_considerations
And also pass some information about the SPI flash type via the SPL
header (for example, the single/dual SPI mode, the maximum SPI clock
speed, etc.). So that the SPL can use this information directly
without any need to have extra code bloat responsible for doing
runtime discovery of all these parameters.
But the most important foolproof feature would be of course a warning
"You are trying to flash a firmware for an incompatible board, are
you really sure?" :-) Later we can also have digital signatures
verification built into the sunxi-fel, and other nice things.
Boris, I think that your NAND use case is not very much different in
principle. You can't expect the users to desolder the NAND chip and
use an external NAND programmer tool when they need to unbrick their
device, right?
--
Best regards,
Siarhei Siamashka
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