Move documentation of README.nand from board files into docs/README.sunxi
Signed-off-by: Jagan Teki jagan@amarulasolutions.com --- Changes for v3: - New patch
board/sunxi/README.nand | 54 -------------------------------------------- doc/README.sunxi | 60 +++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 58 insertions(+), 56 deletions(-) delete mode 100644 board/sunxi/README.nand
diff --git a/board/sunxi/README.nand b/board/sunxi/README.nand deleted file mode 100644 index a5d4ff0..0000000 --- a/board/sunxi/README.nand +++ /dev/null @@ -1,54 +0,0 @@ -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. \ No newline at end of file diff --git a/doc/README.sunxi b/doc/README.sunxi index 48f82cb..c682606 100644 --- a/doc/README.sunxi +++ b/doc/README.sunxi @@ -10,7 +10,8 @@ U-Boot on SunXi Tutorial describe all details relevant for U-Boot on Allwinner SunXi platform.
1. Allwinner 64-bit boards - 2. Verified Boot + 2. Allwinner NAND flashing + 3. Verified Boot
1. Allwinner 64-bit boards ========================== @@ -172,7 +173,62 @@ Then write this image to a microSD card, replacing /dev/sdx with the right device file (see above): $ dd if=firmware.img of=/dev/sdx bs=8k seek=1
-2. Verified Boot +2. 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. + +3. Verified Boot ================
U-Boot supports an image verification method called "Verified Boot".