Tom Rini e8f80a5a58 Merge git://git.denx.de/u-boot-sunxi 6 years ago
..
MAINTAINERS f3df7758b5 board: sunxi: sun8i-v40: Add Bananapi M2 Berry support 6 years ago
Makefile 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 6 years ago
README.nand d2fdcc76e8 scripts: sunxi: Build an raw SPL image 7 years ago
README.sunxi64 35debf8a45 sunxi: README.sunxi64: Add hint about non-debug of ARM Trusted Firmware 6 years ago
ahci.c cf7b2e10c9 dm: sata: sunxi: Add support for driver model 6 years ago
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dram_sun4i_auto.c b0c8f4a797 Kill unneeded #include <linux/kconfig.h> 9 years ago
dram_sun5i_auto.c b0c8f4a797 Kill unneeded #include <linux/kconfig.h> 9 years ago
dram_timings_sun4i.h d133647af4 sunxi: dram: Optionally use standard JEDEC timings for sun[457]i 9 years ago
gmac.c aba3924927 sunxi: Fix A20-OLinuXino-MICRO LAN8710 support 6 years ago
mksunxi_fit_atf.sh 8837af154c sunxi: arm64: correct usage of DT node address in FIT generation 6 years ago

README.nand

Allwinner NAND flashing
=======================

A lot of Allwinner devices, especially the older ones (pre-H3 era),
comes with a NAND. NANDs storages are a pretty weak choice when it
comes to the reliability, and it comes with a number of flaws like
read and write disturbs, data retention issues, bloks becoming
unusable, etc.

In order to mitigate that, various strategies have been found to be
able to recover from those issues like ECC, hardware randomization,
and of course, redundancy for the critical parts.

This is obviously something that we will take into account when
creating our images. However, the BROM will use a quite weird pattern
when accessing the NAND, and will access only at most 4kB per page,
which means that we also have to split that binary accross several
pages.

In order to accomodate that, we create a tool that will generate an
SPL image that is ready to be programmed directly embedding the ECCs,
randomized, and with the necessary bits needed to reduce the number of
bitflips. The U-Boot build system, when configured for the NAND will
also generate the image sunxi-spl-with-ecc.bin that will have been
generated by that tool.

In order to flash your U-Boot image onto a board, assuming that the
board is in FEL mode, you'll need the sunxi-tools that you can find at
this repository: https://github.com/linux-sunxi/sunxi-tools

Then, you'll need to first load an SPL to initialise the RAM:
sunxi-fel spl spl/sunxi-spl.bin

Load the binaries we'll flash into RAM:
sunxi-fel write 0x4a000000 u-boot-dtb.bin
sunxi-fel write 0x43000000 spl/sunxi-spl-with-ecc.bin

And execute U-Boot
sunxi-fel exe 0x4a000000

On your board, you'll now have all the needed binaries into RAM, so
you only need to erase the NAND...

nand erase.chip

Then write the SPL and its backup:

nand write.raw.noverify 0x43000000 0 40
nand write.raw.noverify 0x43000000 0x400000 40

And finally write the U-Boot binary:
nand write 0x4a000000 0x800000 0xc0000

You can now reboot and enjoy your NAND.