[U-Boot] [RFC] Proposal on changing raw boot mode

[Alexander Graf]

On 20/10/2016 19:07, Sam Protsenko wrote:
> Hi guys,
> 
> I'd like to make two changes on how raw MMC address and size of U-Boot
> are represented. But I think it's better to discuss it first, so we
> are on the same page about it.
> 
> Basically I want to review two config options here.
> 
> 1. CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS
> 
>     Simple grep shows us that noone actually uses this constant
> (despite it's being defined for multiple boards). So I'm thinking to
> remove it altogether. What do you think about that?
> 
> 2. CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
> 
>     For TI boards it's defined in common file:
> include/configs/ti_armv7_common.h . So if some board has another
> U-Boot partition address (on MMC), it must redefine that option after
> including ti_armv7_common.h.

I don't understand this part. If you're actually using partitions, just
use the partition code rather than the sector code. The main purpose of
the sector SPL loading code is to allow loading from somewhere that is
*not* a partition, no?

>     Historical background: actually I tried to change this address
> before, because DRA7 EVM and AM57x EVM / X15 boards are broken in
> mainline U-Boot right now. My attempt [1] turned out to be
> ill-designed, as it broke other boards (IIRC, it was BeagleBone
> Black): [2]. Which further led to reverting my patch: [3].
> 
>     It remains to be a problem, though. So I see 2 possible ways how to fix it:
> 
>     (a) Just re-define this address in corresponding board configs (headers).
>     (b) Convert this option to Kconfig and define it correctly in each
> board's defconfig.

Converting to Kconfig is always a good idea. So that one's a no-brainer
"yes, just do it".

As for the overall logic, I find it very hard to follow and terribly
crude. We currently mangle "sector offset u-boot starts" with "partition
number u-boot is on" with various intransparent combinations of those.

Can't we just split CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION and
CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR into

  CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR
  CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
  CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION_OFFSET

Then just model the whole "TI usually sets SECTOR to x" logic in Kconfig
and override it in your board's defconfig.


Alex