On Thu, 2025-12-11 at 13:35 -0800, Marc Olberding wrote:

Add a 128M layout for the BMC flash chip we didn't boot from.
Including
this allows the user to write to each partition on the alternate spi
chip. This dtsi follows the existing standard of using the same
layout
as non alt version and prepending `alt` to each partition's name.

Testing: Include this in msx4 and cat size, offsets and name

for devdir in /sys/class/mtd/mtd*; do
>     [[ -d $devdir && -r $devdir/name ]] || continue
>     name=$(<"$devdir/name")
>     [[ $name == alt* ]] || continue
> 
>     size=$(<"$devdir/size")
>     offset=0
>     [[ -r $devdir/offset ]] && offset=$(<"$devdir/offset")
> 
>     dev=$(basename "$devdir")
>     printf "%s name=%s offset=0x%X size=0x%X\n" "$dev" "$name" \
>        "$offset" "$size"
> done
mtd10 name=alt-rofs offset=0xA00000 size=0x5600000
mtd11 name=alt-rwfs offset=0x6000000 size=0x2000000
mtd7 name=alt-u-boot offset=0x0 size=0xE0000
mtd8 name=alt-u-boot-env offset=0xE0000 size=0x20000
mtd9 name=alt-kernel offset=0x100000 size=0x900000

Also ran dtbs_check on an existing dts with this included.

Signed-off-by: Marc Olberding <redacted>
---
Add a layout for an alternate 128M flash layout. This is
useful for the aspeed ast2500[2] and ast2600[1] SoCs,
where it has the ability to boot from one of two spi chips,
nominally the primary and backup SPIs. Adding a layout allows
userspace
to flash the alternate spi by partition and switch over to it,
allowing
lower downtime for firmware flash, or for updating the primary
flash from the golden backup flash. This is already an established
scheme for the 32M and 64M layouts, where the layout is the same
but each partition has `alt` prepended to its name. This allows
userspace to just prepend alt to the images in the update process
to specify which flash chip to update.

References:

[1] https://www.aspeedtech.com/server_ast2600/
[2] https://www.aspeedtech.com/server_ast2500/
---
 .../dts/aspeed/openbmc-flash-layout-128-alt.dtsi   | 32
++++++++++++++++++++++
 1 file changed, 32 insertions(+)

This may be fine, but please add it in a series that also introduces a
board that consumes it.

Andrew