[U-Boot] [PATCH 0/7] Exynos4412 SPL support

[Simon Shields <simon@lineageos.org>]

Hi Anand,

On Thu, Sep 13, 2018 at 08:39:52PM +0530, Anand Moon wrote:
> Hi Simon,
> 
> On Wed, 12 Sep 2018 at 17:25, Simon Shields <simon@lineageos.org> wrote:
> >
> > Hi,
> >
> > This patch series adds support for using U-Boot's SPL as the second
> > stage bootloader ("BL2") on Exynos4412 SoCs.
> >
> > - Patch #1 adds support for the EMMC/SD OM pin configuration, which is used
> >   by the boards I tested on.
> > - Patch #2 configures the magic values used to indicate system suspend
> >   state (which are identical to exynos5).
> > - Patch #3 renames the existing exynos4 clock/dmc initialisation code
> >   to reflect the fact that it only supports exynos4210.
> > - Patches #4 and #5 add/fill in structs reflecting the PMU and TZASC
> >   register layouts on exynos4412, respectively.
> > - Patch #6 adds the exynos4412 DMC and clock initialisation code and
> >   enables building the SPL on exynos4412 platforms.
> > - Patch #7 enables building the "mkexynosspl" utility for exynos4 SoCs.
> >
> > The majority of the logic in patch #6 comes from a vendor u-boot dump
> > (2010.12!), however, small portions (mostly code used for 2GB RAM
> > initialisation) were reverse engineered from the vendor
> > bootloader found on a GT-N7100.
> >
> > This patch series has been tested on a GT-I9300 (exynos4412, 1GB RAM)
> > and a GT-N7100 (exynos4412 prime, 2GB RAM), with a few additional
> > patchsets applied for board/HW support (which I intend to upstream in
> > the future).
> >
> > Cheers,
> > Simon
> >
> 
> Could you elaborate more on how to generate stage bootloader (BL2) image,
> I am not aware of such process and what are next step to create SPL
> for Exynos platform.
> 
> I have build these patches for Odroid-U3 boards, with no SPL enable.

Of course!

You need to add "select SUPPORT_SPL" to the relevant TARGET_ kconfig
entry (e.g. [0]). Then, you need to configure the SPL suitably in
include/configs/<target>.h - see [1], these values should not need
changing between boards. Finally, you need to enable some SPL
stuff in the defconfig (see [2]). That should allow u-boot to generate
a SPL binary, which should go in spl/<target>-spl.bin.

After that, you need to assemble an image suitable for flashing to an
sdcard/eMMC. I use these two scripts [3], [4] combined with this BL1 [5]
(originally from the ODROID-X u-boot sources, which no longer appear
to be available) for eMMC and sdcard respectively.

The usage of the script is:

./create_4412_<sd|emmc>_image.sh <bl1 binary> <spl binary> <u-boot.bin>
    <outfile>

<outfile> can then be dd'd directly to an SD card or to the eMMC boot0
partition.

Hope that gets things working for you!

Cheers,
Simon

> 
> Best Regards
> -Anand

[0]: https://github.com/fourkbomb/u-boot/blob/4be16a7/arch/arm/mach-exynos/Kconfig#L77
[1]: https://github.com/fourkbomb/u-boot/blob/4be16a7/include/configs/midas.h#L31-L53
[2]: https://github.com/fourkbomb/u-boot/blob/4be16a7/configs/midas_defconfig#L6-L10
[3]: https://github.com/fourkbomb/buildroot-external-midas/blob/master/board/midas/create_4412_emmc_image.sh
[4]: https://github.com/fourkbomb/buildroot-external-midas/blob/master/board/midas/create_4412_sd_image.sh
[5]: https://github.com/fourkbomb/buildroot-external-midas/blob/master/board/midas/p4412_s_fwbl1.bin