stm32mp157c eMMC DDR50 mode

[Sean Nyekjaer]

Hi,

We are testing using the Octavo RED board with OSD32MP157c SoC 
(stm32mp157c).

We are using vanilla u-boot 2022.10(in basic mode without TF-A) and 
Linux kernel version 6.0.x.
I have ported the devicetree's from Octavo combined with upstream 
stm32mp1 boards.
But we are facing issues with running the eMMC in DDR50 mode, works fine 
in normal 50Mhz mode (without the mmc-ddr-3_3v in dts).

It works fine though, with the ST u-boot and ST Linux kernel.

One further note is it seems to work fine, when mounting a squashfs (aka 
readonly) in DDR50.

But ext4 fails with:
root at osd32mp1-red:~# mount /dev/mmcblk0p7 /media/
I/O error, dev mmcblk0, sector 1060144 op 0x1:(WRITE) flags 0x800 
phys_seg 1 prio class 2
Buffer I/O error on dev mmcblk0p7, logical block 422, lost async page write
I/O error, dev mmcblk0, sector 1060016 op 0x1:(WRITE) flags 0x800 
phys_seg 1 prio class 2
Buffer I/O error on dev mmcblk0p7, logical block 406, lost async page write
I/O error, dev mmcblk0, sector 1056768 op 0x1:(WRITE) flags 0x800 
phys_seg 2 prio class 2
Buffer I/O error on dev mmcblk0p7, logical block 0, lost async page write
Buffer I/O error on dev mmcblk0p7, logical block 1, lost async page write

/Sean