Odroid M1 with eMMC?

[peterwilli]

Hey there, I wondered if it was possible to complete the Odroid M1 tutorial (https://github.com/skiffos/SkiffOS/tree/master/configs/odroid/m1) on eMMC since the modules are faster especially if you interact a lot with the persist partition.

I know that SkiffOS lives in RAM, so it hardly matters, but eMMC doesn't mount if you're booting from SD, at least I can't get SkiffOS (nor any other Linux distro supported on this SBC) to recognize it when booted from SD. Thanks!

Edit: I've been playing around with this for a while, and running the identical eMMC module on the Odroid with a eMMC to USB adapter makes it boot from USB directly, so it's clearly a problem with the eMMC connection directly to the board!

[paralin]

Hi, it should boot fine if you flash everything to the EMMC as if it was the SD card.

But; you say you tried this and it didn't work, while using a USB adapter does work.

Checking the logs on the serial debug port would help in this case.

One way you could workaround this in the short term:

• Flash the SD card but delete the "persist" partition after flashing.
• Create a partition labeled "persist" on the emmc.
• Connect both the SD card and Emmc.
• Skiff will use the "persist" labeled partition for storing data.

Use the msdos partition type (not gpt).

When the EMMC is connected to the board you should be able to see it at /dev/mmcblk1 or similar. If not, there might be something preventing the kernel from seeing the emmc (as you've mentioned).

[peterwilli]

Checking the logs on the serial debug port would help in this case.

How can I do this? I haven't done that before! I'd love to help out here.

[paralin]

@peterwilli You need a UART cable:

Connect it to the port on the board that fits the port,

then on your laptop (linux, I hope?)

sudo screen /dev/ttyUSB0 115200

... assuming it went to /dev/ttyUSB0

or you could use minicom -D /dev/ttyUSB0 -b 115200

[peterwilli]

then on your laptop (linux, I hope?)

Always!

I sadly don't have a cable like that. Isn't there a way to output it over the HDMI display cable? I always used that, but on SkiffOS it's completely blank somehow.

I can get a cable like that if no other solution can work...

[paralin]

@peterwilli well, this is for debugging u-boot, for booting from the EMMC. u-boot doesn't output to HDMI, only the serial port.

Here are a few places you can get one:

• https://www.hardkernel.com/shop/usb-uart-module-kit/
• https://www.amazon.com/ODROID-0-USB-UART-Module-Kit/dp/B01LEV2OWA
• https://ameridroid.com/products/usb-uart-module-kit

... if you can't get one, no problem, i'll have some time to test this soon and make sure it works.

[peterwilli]

@peterwilli well, this is for debugging u-boot, for booting from the EMMC. u-boot doesn't output to HDMI, only the serial port.

Here are a few places you can get one:

* https://www.hardkernel.com/shop/usb-uart-module-kit/

* https://www.amazon.com/ODROID-0-USB-UART-Module-Kit/dp/B01LEV2OWA

* https://ameridroid.com/products/usb-uart-module-kit

... if you can't get one, no problem, i'll have some time to test this soon and make sure it works.

I'll buy one today if I can't get it to run with Arduino because it's probably faster to build one myself with Arduino (done it before) than to wait for one to ship. On the other hand, I don't have a build lying around anymore, so maybe it's better to buy one online anyway as it takes time before it's completed.

Edit: all set up for when the build is completed! Edit2: Nvm it's probably never going to work, their default baud rate is way too high, and I don't see a way to change it from the boot menu or anything (see: https://wiki.odroid.com/_detail/odroid-m1/software/odroid-m1_uart_setup.png?id=odroid-m1%3Asoftware%3Auart_debugging). Arduino goes to max 115200 baud rate.

I'm gonna try to find a shop where I can buy one in the Netherlands because that's where I live

I found this one: https://www.odroid.nl/odroid-accessories/odroid-development/odroid-usb-uart but idk if it's compatible with Odroid M1 as the page doesn't list M1 as a compatible board.

[peterwilli]

I managed to buy this. I think it'll be compatible as the chip is the same as on the Odroid version, it's cheaper and in stock and can be shipped tomorrow so that's nice as well.

[peterwilli]

I got it to hook up to my best knowledge (not sure if I did it right, but took a peek at this image: https://i.imgur.com/Y80TsBol.png) but get a bunch of binary characters.

My setup:

[paralin]

@peterwilli baudrate is wrong, or there are multiple instances of screen running.

Maybe try "sudo killall -9 screen"

Then use the higher baudrate for the M1:

screen /dev/ttyUSB0 1500000

[peterwilli]

@paralin the eMMC works now! I just tried your update and it's there.

root@skiff-a48e7829:~# lsblk
NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
loop0          7:0    0  39.2M  0 loop /usr/lib/modules
mmcblk1      179:0    0 119.4G  0 disk 
|-mmcblk1p1  179:1    0     2G  0 part /mnt/rootfs
|                                      /mnt/boot
`-mmcblk1p2  179:2    0 117.4G  0 part /etc/ssh
                                       /var/log/journal
                                       /mnt/persist
mmcblk0      179:32   0  58.2G  0 disk 
|-mmcblk0p1  179:33   0   256M  0 part 
`-mmcblk0p2  179:34   0    58G  0 part 
mmcblk0boot0 179:64   0     4M  1 disk 
mmcblk0boot1 179:96   0     4M  1 disk 
zram0        253:0    0     2G  0 disk [SWAP]

The mmcblk0 module is the eMMC. I'll try to boot from it now, but this is already great.

Thanks so much for helping out in both cases. If you want, I can still try the serial thingy, but I doubt we see any error now :laughing:

Shall I close this issue?

Ok booting from it didn't work, but that's ok, for the sake of completion I'll get some serial data if I can from the M1 to see what it says.

Edit: I tried both sudo killall -9 screen and screen /dev/ttyUSB0 1500000 but the output still doesn't make sense. I guess it's my adapter that isn't working!

[peterwilli]

Hi, it should boot fine if you flash everything to the EMMC as if it was the SD card.

But; you say you tried this and it didn't work, while using a USB adapter does work.

Checking the logs on the serial debug port would help in this case.

One way you could workaround this in the short term:

* Flash the SD card but delete the "persist" partition after flashing.

* Create a partition labeled "persist" on the emmc.

* Connect both the SD card and Emmc.

* Skiff will use the "persist" labeled partition for storing data.

Use the msdos partition type (not gpt).

When the EMMC is connected to the board you should be able to see it at /dev/mmcblk1 or similar. If not, there might be something preventing the kernel from seeing the emmc (as you've mentioned).

I tried this, and while my eMMC is now recognized, the persist partition isn't automatically mounted...

My lsblk:

root@skiff-a48e7829:~# lsblk
NAME         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
loop0          7:0    0 39.9M  0 loop /usr/lib/modules
mmcblk1      179:0    0 14.8G  0 disk 
`-mmcblk1p1  179:1    0    2G  0 part /mnt/rootfs
                                      /mnt/boot
mmcblk0      179:32   0 58.2G  0 disk 
`-mmcblk0p1  179:33   0 58.2G  0 part 
mmcblk0boot0 179:64   0    4M  1 disk 
mmcblk0boot1 179:96   0    4M  1 disk 
zram0        253:0    0    2G  0 disk [SWAP]

Gparted of SD card:

Gparted of eMMC:

Could it be because I don't have a core? I'll test out with the persist on the SD just to be sure.

Edit: it works when the persist in on SD:
root@skiff-a48e7829:~# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
loop0         7:0    0 39.9M  0 loop /usr/lib/modules
mmcblk1     179:0    0 14.8G  0 disk 
|-mmcblk1p1 179:1    0    2G  0 part /mnt/rootfs
|                                    /mnt/boot
`-mmcblk1p2 179:2    0 12.8G  0 part /etc/ssh
                                     /var/log/journal
                                     /mnt/persist
zram0       253:0    0    2G  0 disk [SWAP]

Edit: I also tested with GPT as partition table on the eMMC, but it didn't want to mount either :(

[paralin]

@peterwilli the boot process is separate from core and all the other application level stuff. It's contained purely in the configs-base and the device packages.

Will try it out with my M1 and see what needs to be changed to make it work

[peterwilli]

@peterwilli the boot process is separate from core and all the other application level stuff. It's contained purely in the configs-base and the device packages.

Will try it out with my M1 and see what needs to be changed to make it work

Thanks, I'll be awaiting your response, and thanks for explaining!

[paralin]

@peterwilli Ok, I traced it, the EMMC driver needed to be compiled built-in instead of as a module; this is because the modules are not available until after the EMMC is accessed (and persist is mounted).

CONFIG_MMC_SDHCI_OF_DWCMSHC=y

Fixed: 925dcecc768948deff4a57221590db759aa47240

Please git pull, rm -rf workspaces/default/build/linux-custom then make compile and run the install command again to update the files on the SD card.

Keep in mind: the first boot, it will need to allocate the swapfile on the emmc, which takes ~30 seconds before Docker starts.

[peterwilli]

@peterwilli Ok, I traced it, the EMMC driver needed to be compiled built-in instead of as a module; this is because the modules are not available until after the EMMC is accessed (and persist is mounted).

CONFIG_MMC_SDHCI_OF_DWCMSHC=y

Fixed: 925dcec

Please git pull, rm -rf workspaces/default/build/linux-custom then make compile and run the install command again to update the files on the SD card.

Keep in mind: the first boot, it will need to allocate the swapfile on the emmc, which takes ~30 seconds before Docker starts.

I'm super grateful, I can't promise I can try it today due to getting my wisdom tooth removed, and I have no idea how I am afterward, but I'll definitively aim to try this today. Also, thanks for letting me know what the issue is and how you solved it, this really helps to see how things work, and maybe figure things out myself as well.

[peterwilli]

Alright, I think we can close this. Not only does SD work, but booting from eMMC entirely works like a charm! Thanks so much!

[paralin]

@peterwilli glad to hear it!