Re: STM32MP157

Hello, I need an advice on the intial addresses layout when booting the 
kernel.
As I understand, ubldr is the proper way to boot the kernel. 
What is the correct address to load it, given that I wand to keep default 
KERNVIRTADDR (=0xc0000000) intact?
The u-boot loads ubldr this way in my current setup:
// FreeBSD version of environment
env_set("baudrate", "115200");
env_set("console", "ttyS0,115200");
env_set("stderr", "serial");
env_set("stdin", "serial");
env_set("stdout", "serial");
env_set("autostart", "yes");
env_set("loaderdev", "mmc 1"); // fbsd's ubldr treats our second mmc at 
index 1
env_set("bootcmd", "fatload mmc 2 0xc0000000 ubldr && bootelf");
then ubldr leads the kernel from mmc and passes it the control:
Loading kernel...
/boot/kernel/kernel text=0x1b4 text=0x5b8530 text=0x17d91c data=0xa4a60 
data=0x0+0x20c000 0x4+0x88810+0x4+0xe9d98|
Loading configured modules...
can't find '/boot/entropy'
can't find '/etc/hostid'
Using DTB compiled into kernel.
Kernel entry at 0xc0400200...
Kernel args: (null)
Then I could correctly pass the init of MMU and get into translated mode 
only with setting KERNVIRTADDR = 0xc4000000. It looks like kernel and 
loader clash somehow. 
So, just need to understand what is best option to load ubldr to? Will it 
affect further routines?
Stan
Stanislav Silnicki wrote:
OK, I got the idea!
As I realize, there is a minor bug in dtc, which affects compilation of 
stm's originated DTBs. I think it is best to make a PR into 
https://github.com/davidchisnall/dtc, 
<https://github.com/davidchisnall/dtc,> which I'm discussing with repo 
owner already. Please tell me, that I need to post PR into FBSD source tree 
if it is a shorter way for my fix.
My current setup is based upon QBASE1 from Karo-Electronics, but there is 
no goal to support/debug all peripherals, only a subset, including USB, 
I2C, SDMMC, DSI (and GPU, if lucky).
https://www.karo-electronics.com/fileadmin/download/Datasheets/QSMP-QSBASE1-Evalkit.pdf 
<https://www.karo-electronics.com/fileadmin/download/Datasheets/QSMP-QSBASE1-Evalkit.pdf> 

The vendor (Karo) supports only their Yocto based Linux distro. I spent 
some time to prepare TF-A & Uboot, capable with booting from SD card (that 
is more robust approach, as I think). STM does not promote/support 
non-secure boot approach with SPL, they insist to use TF-A or OPTEE, so it 
is pretty cumbersome path, I had to pass. I think, it will be easier for me 
to prepare some sort of README to support customization of uboot for STM's 
port and dig it somewhere in SRC rather than ;try to post PR's in those 
repos... Not sure, anyway.
So far I'm struggling with uart and early_printf...
I'm mixing this activity with my current occupation, so I don't expect 
rapid progress.
Thank you for clarifications! I'll try to do my best!
Stan
Oskar Holmlund wrote:
Hi Stanislav,
Please resend your message and CC the arm mailing list. It might be 
interesting for someone in the future ( 
https://lists.freebsd.org/archives/freebsd-arm/ ) otherwise they all think 
you stopped working on the STM32 port.
You should always keep one terminal up n running % man 9 style :)
https://wiki.freebsd.org/Phabricator will give you some information.
Its good if you get to know the people active in the ARM area, just keep an 
eye on the mailinglist and you will notice some names. If you have the 
opportunity to join any of the conference (eurobsdcon.org, asiabsdcon.org, 
bsdcan.org) to get to know even more people.
Join the IRC, for example on efnet #bsdmips is a good channel for ARM 
stuff.
Start with small changes and you will get feedback. From there the 
experience will grow and you will get into it all.
Correct, the device-tree import is from the Linux kernel and there is no 
prior work for the STM32MP15 SoCs. I cant find anything about the 
STM32MP15x in Net or OpenBSD either.
Probably because the STM32MP15 is the first(?) application SoC from ST?
1) hum? Do you need that for the reviews? It should be in SRC
2) Target branch is probably main.
3) It depends, if your custom board is opensource and availble around the 
globe through mouser/farnell/.. I dont see any problem. Otherwise pick the 
board from ST that you used as a reference when you developed the custom 
board.
For example in my day job we have a custom board built around the 
octavosystems OSD3358 that can be found in pocketbeagle/beaglebone black 
wifi. So the code thats goes into the FreeBSD project are all tested on the 
beaglebone boards. The stuff we need for our custom board like the device 
tree is keept as local patches in our inhouse build process.
//Oskar
2023-10-28 14:25 skrev Stanislav Silnicki:
Hi Oskar!
 > can you point me some guidelines to help myself to fit development
process? I'm sure, there is mature dev. culture around FBSD and I'd be
happy to make my contribution coherently from the beginning.
 > So far I'm done with setup of my account at reviews (keys, 2FA, etc.)
 > As I understand, there is no considerable progress with STM32,
although I have noticed, there are some DTS imported into the project.
 > > Indeed, several major questions:
1. repo url?
2. tagret branch for patches for stm32 hw?
3. is it possible to target custom board from our project, or I have
to ensure support for all dev. boards, provided by STM?
 > Thank you,Stan
 > Oskar Holmlund wrote:
 >> 2023-10-27 22:33 skrev Stanislav Silnicki:
<block
quote class="gmail_quote" type="cite" style="margin:0 0 0 
.8ex;border-left:1px #ccc solid;padding-left:1ex">
 >>> Hello!
I'm porting onto the subject hardware. So far the progress is
modest,
while the system boots (without console although...)
One of major issues is hardcoded value inside locore-v6.S. Here
is my
relevant post:
 >> > 
https://community.st.com/t5/stm32-mpus-embedded-software/freebsd-port-for-mp157c/td-p/601438

[1]
What is the best way to proceed? Patch, vendor kernel build,
something
else?
Stan
 > Links:
------
 >> [1] >
 > 
https://community.st.com/t5/stm32-mpus-embedded-software/freebsd-port-for-mp157c/td-p/601438
 
>> Hi Stan,
 >> Upload your patch to reviews.freebsd.org
 >> Love to see your other patches for the STM32MP15x.
kquote>
</block
 >> //Oskar