boards/nrf52840-mdk-dongle: add nRF52840 MDK USB Dongle

[benpicco]

Contribution description

The nRF52840 MDK USB Dongle is another widely available nRF52840 Dongle.
It is ostensibly similar to the reference design (nrf52840dongle) but differs in several aspects.
(fewer GPIOs, one less LED, different bootloader and an external voltage regulator that provides up to 1A @ 3.3V)

It comes with the UF2 bootloader and is flashed using uf2conv.py.
The utility will convert the .hex file into a .uf2 file and copy it to the mass storage device that the bootloader creates for this purpose.

This works well with auto-mount, if you are mounting manually, additional steps are needed.

Testing procedure

The usual nRF52 things should work.

For the first flashing, you have to enter the bootloader manually by pressing the Reset button while plugging the device in.
Subsequent flashes should perform the bootloader reset automatically.

The uf2conv.py utility will be fetched automatically.

Issues/PRs references

[maribu]

I assume I could just test this on an nRF52840 Dongle, provided that the U2F bootloader (that I have installed anyway) is on it?

[benpicco]

The pins will be different.
But there is not much more than the nRF52840 on it besides that.

There are several config options to the UF2-bootloader.
Check out mdk_nrf52840_dongle.

[kaspar030]

I don't have hardware to test, but otherwise, LGTM.

[kaspar030]

I tested the uf2 flashing procedure (with a different board, but same includes).
I don't have the mentioned auto-mounter, but "reset into bootloader, mount manually, then make flash-only" works fine. On arch, I need a symlink, ln -s /run/media /media.

[fjmolinas]

@benpicco do you mind adding some tests results? Otherwise if @kaspar030 thinks his testing is enough he can ACK.

[benpicco]

What tests world you like to see?
@man0lis has the board 🙂

[fjmolinas]

What tests world you like to see?

Ideally compile_and_test_for_board

[benpicco]

A problem I'm getting a lot with the automated tests is

[31247.269093] blk_update_request: I/O error, dev sde, sector 1 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
[31247.269101] Buffer I/O error on dev sde, logical block 1, lost async page write
[31247.269126] blk_update_request: I/O error, dev sde, sector 33 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
[31247.269128] Buffer I/O error on dev sde, logical block 33, lost async page write
[31247.269178] blk_update_request: I/O error, dev sde, sector 70 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[31247.269204] blk_update_request: I/O error, dev sde, sector 65 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
[31247.269207] Buffer I/O error on dev sde, logical block 65, lost async page write
[31247.269226] blk_update_request: I/O error, dev sde, sector 70 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269253] blk_update_request: I/O error, dev sde, sector 65 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269263] FAT-fs (sde): unable to read inode block for updating (i_pos 1041)
[31247.269379] blk_update_request: I/O error, dev sde, sector 65 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269451] FAT-fs (sde): Directory bread(block 65) failed
[31247.269465] blk_update_request: I/O error, dev sde, sector 66 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269470] FAT-fs (sde): Directory bread(block 66) failed
[31247.269479] blk_update_request: I/O error, dev sde, sector 67 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269484] FAT-fs (sde): Directory bread(block 67) failed
[31247.269492] blk_update_request: I/O error, dev sde, sector 68 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[31247.269497] FAT-fs (sde): Directory bread(block 68) failed
[31247.269590] FAT-fs (sde): Directory bread(block 65) failed
[31247.269600] FAT-fs (sde): Directory bread(block 66) failed
[31247.269612] FAT-fs (sde): Directory bread(block 67) failed
[31247.269621] FAT-fs (sde): Directory bread(block 68) failed

when the board resets itself after flashing (writing the firmware to the mounted 'drive')
It seems like it prematurely restarts itself and then boots into the old firmware.

For a reason yet unknown, this does not happen when I manually run make BOARD=nrf52840-mdk-dongle flash test.

The bootloader gets auto-mounted as

/dev/sde on /media/benpicco/MDK-DONGLE type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)

Maybe I have to re-mount it with the sync option?

[benpicco]

I still get some

[30320.056563] blk_update_request: I/O error, dev sdd, sector 65 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[30320.056567] Buffer I/O error on dev sdd, logical block 65, lost sync page write

with

sudo mount -o remount,rw,sync,noatime /dev/sdd /media/benpicco/MDK-DONGLE

but the firmware gets written correctly. Same without the remount though.

[aabadie]

Please rebase and squash!

[benpicco]

squashed.

still flashes and no more duplicate pings thanks to #15132

2020-12-02 10:30:15,560 #  version
2020-12-02 10:30:15,562 # 2021.01-devel-1298-g081c6-boards/nrf52840-mdk-dongle
2020-12-02 10:39:37,121 #  ping fe80::fec2:3d00:0:bb1
2020-12-02 10:39:37,133 # 12 bytes from fe80::fec2:3d00:0:bb1%7: icmp_seq=0 ttl=64 rssi=174 dBm time=9.253 ms
2020-12-02 10:39:38,133 # 12 bytes from fe80::fec2:3d00:0:bb1%7: icmp_seq=1 ttl=64 rssi=178 dBm time=9.893 ms
2020-12-02 10:39:39,134 # 12 bytes from fe80::fec2:3d00:0:bb1%7: icmp_seq=2 ttl=64 rssi=178 dBm time=10.211 ms
2020-12-02 10:39:39,134 # 
2020-12-02 10:39:39,135 # --- fe80::fec2:3d00:0:bb1 PING statistics ---
2020-12-02 10:39:39,136 # 3 packets transmitted, 3 packets received, 0% packet loss
2020-12-02 10:39:39,138 # round-trip min/avg/max = 9.253/9.785/10.211 ms

[aabadie]

ACK