[PATCH] odroid-go2: remove setting SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR

[Heiko Stuebner <heiko.stuebner@theobroma-systems.com>]

Hi Tom,

Am Dienstag, 16. Februar 2021, 15:26:52 CET schrieb Tom Rini:
> On Sat, Feb 13, 2021 at 11:45:50PM +0100, Heiko Stuebner wrote:
> > Hi Roger,
> > 
> > Am Samstag, 13. Februar 2021, 16:59:01 CET schrieb Roger Pau Monne:
> > > From: Roger Pau Monn? <royger@FreeBSD.org>
> > > 
> > > Using a non-default SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR setting makes the
> > > resulting u-boot-rockchip.bin unbootable, as it gets stuck after SPL.
> > > Removing the setting from the defconfig allows U-Boot to load
> > > successfully.
> > 
> > Hmm, I'd disagree slightly.
> > 
> > In the rockchip-common.h the CONFIG_SPL_PAD_TO is defined as
> > 
> > /* ((CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR - 64) * 512) */
> > #define CONFIG_SPL_PAD_TO		8355840
> > 
> > so it's a static value but based on the MMCSD_RAW_MODE... config option.
> > 
> > So instead of mandating one specific MMCSD_RAW_MODE... value
> > that CONFIG_SPL_PAD_TO should be defined based on the the
> > actual config value of CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
> > and not some static number that then gets enforced for all boards.
> 
> So, what does CONFIG_SPL_PAD_TO actually mean, in this case?  And
> SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR ?  What I'm getting at is that we
> generally have some required to be fixed (by the SoC/ROM/etc) locations
> some parts of our SPL/TPL/U-Boot need to be at and then the rest of the
> values are (supposed to be) well and carefully chosen offsets and not
> changed around.  So with the above comment in the code to explain where
> 8355840 came from, it also shouldn't and nor should
> CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR be changed without a compelling
> reason.

Normally Rockchip platforms have two loader binaries:

- idbLoader.img (tpl + spl, or only spl), loving at offset 64 of a sd-card
  This is mandated by the bootrom
- u-boot.itb (u-boot, atf, etc) living at SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
  As SPL will load from the location specified in the config, this location
  can be set depending on emmc/sd-card/whatever needs.

It looks like recently a new binary creating method was added that creates
a u-boot-rockchip.bin combining these somewhat automatically:

idbLoader.img
+ SPL_PAD_TO
+ u-boot.itb

So that only that binary needs to be flashed to the boot medium
instead of two.

So the SPL_PAD_TO essentially would mandate one specific
SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR for every board.


For the odroid-go2 itself it doesn't really matter I guess, but there are
other boards with different requirements, so mandating one specific place
for the main uboot for all boards that will ever exist seems a bit counter-
intuitive to me.


Heiko