Xilinx SOC AARCH64 ARM64 Embedded Boot To SATA

RayDude

I'm installing Gentoo on a Xilinx SOC FPGA development board to make it easier to develop code.

I'm not ready yet to deal with peta-linux. I mean it works, but it's a pita-linux.

u-boot (from peta-linux) on this development board is not up to snuff. For example, the built in MMC had a boot image installed, which is great, but I stopped it at boot, dropped to a u-boot prompt and did a 'saveenv' (to eliminate the corrupt environment error message at boot) and that corrupted the peta-linux boot image which won't boot anymore. I'll replace it with the image I built with peta-linux once I get Gentoo running properly.

Right now I'm booting a huge peta-linux BASE image from SDCard that is from Feb of 2022. I have a gentoo base install on a SATA NVMe which reads at hdparm -tT speeds of 300 MB/Second, pretty good, right?

But I have no idea how to make it boot from SATA. The dev board doesn't have a boot from SATA option and since I can't save the u-boot environmental variables, I'll have to do a manual load every time I boot, which is less than user friendly.

I'm thinking I'm going to have to do a special u-boot whose env vars work. It has to be done eventually anyway, but I was hoping since I'm going to be doing more software and firmware development on this board in the beginning if someone could help me find a short cut to booting gentoo from the SATA NVMe.

That's long, thanks for reading!
_________________
Some day there will only be free software.

NeddySeagoon · Posted: Tue May 30, 2023 2:02 pm Post subject:

RayDude,

There is a difference between 'boot from' and 'boot to'

Boot from places a requirement on the firmware to be able to read from the desired device.
Its game over if the firmware does not do what you want.

I read 'boot to' as a requirement on the kernel to mount root from the desired device.
That needs kernel and possibly initrd support. That's much easier as its mostly under your control.

There is a half way house too. Consider a boot leader that keeps the firmware happy but all it does is load another boot loader that is easier to manipulate.

e.g. early Raspberry Pis can only boot from the SD card but root can be anywhere the kernel can see. USB, NFS, even the SD card.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

RayDude · Posted: Wed May 31, 2023 9:32 pm Post subject:

RayDude · Posted: Thu Jun 01, 2023 10:02 pm Post subject:

Hi Neddy,

I got it to boot by creating an extlinux.conf file and forcing u-boot to run bootcmd_scsi0.

But it's hanging, here's a log:

I seem to remember something like this from amd64, but it's been a long time... Any ideas what I borked or failed to do?

RayDude · Posted: Thu Jun 01, 2023 10:35 pm Post subject:

Update. I remembered. /etc/inittab:

s0:12345:respawn:/sbin/agetty -L 115200 ttyPS0 vt100

It announces that it's up and gives me a login prompt but does not accept key input...
_________________
Some day there will only be free software.

NeddySeagoon · Posted: Fri Jun 02, 2023 5:04 pm Post subject:

RayDude,

You have a bit missing from the kernel but you are getting there. :)

How is the keyboard connected?
What kernel version are you using?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

RayDude · Posted: Sat Jun 03, 2023 4:10 am Post subject:

NeddySeagoon · Posted: Sat Jun 03, 2023 8:03 am Post subject:

RayDude,

Moved from Other Things Gentoo to Gentoo on ARM.
Its one of these.

When that Xilinx SOC works, add it to the ARM hardware list.
Maybe donate a Wiki page too, in case you need to do it again

_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

RayDude · Posted: Sun Jun 11, 2023 7:16 am Post subject:

RayDude · Posted: Tue Jul 04, 2023 9:31 pm Post subject:

Update.

I have been trying to get the PCI x1 port to work. I need it to work for my hobby project. I have not been able to get it to work even with avnets flash images.

The card I plug in is not seen, does not train, etc etc etc.

I finished checking that the reset_n signal to the PCIE port is high as it should be and the wake_n signal is low as it is supposed to be.

Then I realized after looking at this board for months that I was plugging the display port connector into the wrong port.

I thought, "well that explains why video doesn't work. Who knew they put a display port out on the fpga side of the device."

So I plugged in the proper display port and tried to bring up video.

Not a single image from avnet worked. startx looked like it was running, but the video only flickered on and off about once every 20 seconds.

I had all but given up and I thought, why not try booting gentoo...

So I booted off the Gentoo SATA SSD and boom, video is up on a console with a login prompt.

GOOD OLD GENTOO!

Now if I could get the usb port to work I could plug in a keyboard...

Wow. This is like pulling your own teeth with tweezers.

Anyway.

GOOD OLD GENTOO!
_________________
Some day there will only be free software.

RayDude · Posted: Tue Jul 04, 2023 10:02 pm Post subject:

Hi Neddy.

My display hardware is being detected by the kernel and initialized, but I have no idea what it is, nor do I have any idea what VIDEO_CARDS should be set to. fbdev does not work.

I'm not even sure that gentoo supports this hardware...

NeddySeagoon · Posted: Sat Jul 08, 2023 6:06 pm Post subject:

RayDude,

RayDude · Posted: Tue Jul 11, 2023 11:17 pm Post subject:

RayDude · Posted: Wed Jul 12, 2023 6:29 am Post subject:

Update: USB is working with the example SOC configuration.

I diffed my config and their config and found USB DWC is disabled in mine.

Why?

Because there is a compile error with it enabled. I didn't realize it was important and disabled it over a month ago to get the kernel to compile.

Now I have to debug the kernel. Not my first rodeo, but I'm viscously slow at it.

RayDude · Posted: Thu Jul 13, 2023 1:32 am Post subject:

It's so weird. Last night in the wee hours I got USB working. I had video coming out of the display port with a text console that was working.

Today, when I powered up, it stopped working.

Inconsistency is the bane of all engineering work.
_________________
Some day there will only be free software.

RayDude · Posted: Thu Jul 13, 2023 1:56 am Post subject:

Okay. The Xilinx SOC does not like the DisplayPort to HDMI converter I have.

If I power up with the DisplayPort connected to my 4K monitor I get video.

The xorg log indicates that fbdev is not necessary and unloads it:

RayDude · Posted: Thu Jul 13, 2023 5:14 pm Post subject:

Update.

Sometimes the display works and sometimes it doesn't.

Here's dmesg when it doesn't:

RayDude · Posted: Sat Jul 15, 2023 11:19 pm Post subject:

The Xilinx hacked kernel is a bit of a mess.

The video output of the board works once in a while, but mostly it does not work.

I have not been able to find a way to make it work every time.

I've convinced myself that the hacked kernel has a race condition

So I decided to turn the Xilinx video out driver into a module so I can load it later and debug it with printf statements or maybe gdb if possible.

But the kernel won't build the Xilinx displayport drivers as modules because the code itself is incomplete.

I had to add MODULE_LICENSE to three source files and I had to add SYMBOL_EXPORT to roughly 60 functions.

Now I get these error messages:

RayDude · Posted: Thu Aug 03, 2023 9:14 pm Post subject:

Update.

I have the display port driver loading as a module, but that didn't help.

I found a thread on a Xilinx forum about the issue with display port. The problem is: the display port on this dev board only supports one lane of SERDES and the 4K monitor I have requires 2 lanes to run native. The monitor says: I can do 4K and the linux driver attempts 4K and then it doesn't work because a lane is missing. I think the driver should be smarter than that, but I can't blame them, it's an unusual board.

Since the linux driver does not know to limit to a lower resolution / refresh rate, it attempts to connect at 4K-60 and because one line is missing the display gets really confused which accounts for it syncing with no video for a moment, then going to sleep then repeating ad-infinitum.

I either need another monitor that can do just one lane display port, which I don't have. Or I need someway to tell the driver to force 1080p which will work as I've seen it working through some quirk of playing with a DP to HDMI adapter I have.

I also have my own dts working. It's just a hack of an existing one for the 6.4.2 kernel that I adjusted to support this board. The big trick was to assume that u-boot set the pin muxes and GPIO correctly and not let the dts adjust them based on the file I copied, because pinctrl is completely different for this board, compared to the ZCU-104 I copied. I just commented out all the pin configuration stuff and features started working.

USB is up and running.

PCIe is still not working. I suspect that's because u-boot is not correctly configuring GPIO for reset / interrupt / something else or serdes for the single PCIe lane.

Debugging that is going to take time as I have to reverse engineer how it's connected on the board and then learn how to configure the pinmuxes and gpios.

I've been putting that off for long enough I guess.
_________________
Some day there will only be free software.

NeddySeagoon · Posted: Fri Aug 04, 2023 5:21 pm Post subject:

RayDude,

You can force any ramdom display mode you want.

For the console, its a kernel command line thing.
For Xorg its a xor.conf.d/ fragment.

Connect the display somewhere where it works and post the entire Xorg.0.log file please.
I'm looking for the part that lists the modes that the display supports.
Being lazy, pick one and turn it into a modeline for Xorg.

You should be able to gen 4k at 30Hz but that may be a bit ugly.
If you can see the flicker, it will give you headaches. It might even if you can't notice the flicker.

From my display I get.

RayDude · Posted: Mon Aug 07, 2023 12:11 am Post subject:

Thanks Neddy.

I'm getting there. I learned how the psgtr driver works on modern linux kernels.

It doesn't actually seem to do anything though so I'm not sure if I wasted my time as the kernel seems to ignore any phy="" command I give it.

But I was able to determine how to get my monitor to work with the single lane DisplayPort.

The secret is to leave the monitor off until it goes to sleep, then boot the Xilinx board. The display will initialize properly then.

If you don't wait, I think the monitor and the board never really understand that there is only one lane.

I have X up and running on the example linux build. It's just a matter of time before I get my dts file working.

Its too bad that avnet hasn't updated their example builds to use a later version of the kernel, it would have saved me a lot of time.

I will not run a 5.15 kernel and be stuck there, I just can't do it.
_________________
Some day there will only be free software.

RayDude · Posted: Tue Sep 05, 2023 8:46 pm Post subject:

I don't know if anyone is still following this thread, but I can't get debug information from the kernel.

I followed several guides to configure the kernel, set logging levels as high as possible, but I still am not seeing anything on the console, in dmesg or in syslog...

None of the debug messages are showing up.

I have dynamic debug enabled, I'm passing the debug parameter to the kernel.

I set the default debug levels as high as possible and I even set printk to 7 and 8 trying to get some form of message from the kernel, but nothing happens, it's as if the debug features were turned off.

Based on googling about it looks like aarch64 supports dynamic debug.

I guess I'll just have to change all the dev_dbg and dev_err messages to printk, in the source code like I did a couple years ago debugging altera Cyclone III PCI.

Unless you guys can save me the hassle...

*crosses fingers*
_________________
Some day there will only be free software.

NeddySeagoon · Posted: Wed Sep 06, 2023 3:52 pm Post subject:

RayDude,

I'm following but you are way out of my comfort zone.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pingtoo · Posted: Wed Sep 06, 2023 5:08 pm Post subject:

RayDude,

I don't know much of kernel debugging, but I think you can control how printk work by changing value in /proc/sys/kernel/printk

You can check the current console_loglevel with:

RayDude · Posted: Thu Sep 07, 2023 1:28 am Post subject: