Physical devices mapping (BELK/BXELK)

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This article details how physical devices are handled by the Linux kernel in the context of the BELK and BXELK kits.

History[edit | edit source]

Version Date BELK/BXELK version Notes


Apr 2019 3.0.0 BELK 3.0.0
2.0.0 Jan 2020 4.1.0 Updated for BELK/BXELK 4.1.0

Console UART[edit | edit source]

Kit Physical device Processor's resource Connector Type Linux device file Notes
BELK Boot Console UART1 J17 2-wire RS232 UART /dev/ttyPS0
BXELK Boot Console UART1 J17 2-wire RS232 UART /dev/ttyPS0

Ethernet[edit | edit source]

Ethernet port is associated to eth0 interface on the J8 connector. It can be managed with standard Linux commands. See for example

LED[edit | edit source]

The two LEDs, connected to the ethernet PHY are configured as Tri-color dual-LED mode (see more info in the KSZ9031 datasheet): link/activity for 100mbit/s and link/activity/ for 1000mbit/s.

microSD card[edit | edit source]

microSD card on connector J21, if present, will be associated by the Linux kernel to the mmcblk0 device:

[   24.100643] mmc0: new high speed SDHC card at address 1234
[   24.106544] mmcblk0: mmc0:1234 SA16G 14.6 GiB
[   24.113268]  mmcblk0: p1 p2

Once detected, it can be mounted and accessed via usual Linux commands:

root@bora:~# mount /dev/mmcblk0p1 /mnt/mmcblk0p1/
root@bora:~# time cp LibreOffice_4.1.1_Win_x86.msi /mnt/mmcblk0p1/

real    0m39.971s
user    0m0.080s
sys     0m4.120s
root@bora:~# ls -la /mnt/mmcblk0p1/LibreOffice_4.1.1_Win_x86.msi
-rwxr-xr-x    1 root     root     215056384 Nov 15 15:57 /mnt/mmcblk0p1/LibreOffice_4.1.1_Win_x86.msi
root@bora:~# umount /mnt/mmcblk0p1/

NOR and NAND flash[edit | edit source]

200px-Emblem-important.svg.png NOR and NAND flash memories cannot be accessed at the same time because they shares some Zynq pins. In U-boot the switching between accesses to NOR and NAND is automatically done by U-boot itself. By default in kernel only NAND flash can be accessed. For NOR support in kernel please contact technical support. 200px-Emblem-important.svg.png

NOR and NAND flashes are managed as MTD devices.

Generally speaking, NAND flash memory partitions are defined using the kernel command line:

Bora> pri mtdparts

adding addmisc to the bootargs parameters list.

The kernel dmesg will configure the NAND partitions in the following way:

[    1.148350] Creating 8 MTD partitions on "pl35x-nand":
[    1.153486] 0x000000000000-0x000000040000 : "spl"
[    1.170502] 0x000000040000-0x000000100000 : "uboot"
[    1.186404] 0x000000100000-0x000000140000 : "env1"
[    1.202301] 0x000000140000-0x000000180000 : "env2"
[    1.218170] 0x000000180000-0x000000780000 : "fpga"
[    1.229456] 0x000000780000-0x000000800000 : "fdt"
[    1.237981] 0x000000800000-0x000001000000 : "kernel"
[    1.244063] 0x000001000000-0x000040000000 : "nand-ubi"
root@bora:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00040000 00020000 "spl"
mtd1: 000c0000 00020000 "uboot"
mtd2: 00040000 00020000 "env1"
mtd3: 00040000 00020000 "env2"
mtd4: 00600000 00020000 "fpga"
mtd5: 00080000 00020000 "fdt"
mtd6: 00800000 00020000 "kernel"
mtd7: 3f000000 00020000 "nand-ubi"

USB OTG[edit | edit source]

Host mode[edit | edit source]

For the USB Host mode an USB stick or another device must be pluged in at the system boot. See the issue related to USB not hotplug capable after the system boot.

This example shows how a memory stick is detected by the Linux kernel.

root@bora:~# [   37.340873] usb 1-1: new high-speed USB device number 2 using zynq-ehci
[   37.508377] usb 1-1: device v05e3 p0736 is not supported
[   37.514823] usb-storage 1-1:1.0: USB Mass Storage device detected
[   37.521869] scsi host0: usb-storage 1-1:1.0
[   38.522235] scsi 0:0:0:0: Direct-Access     Generic  STORAGE DEVICE   0272 PQ: 0 ANSI: 0
[   38.531274] sd 0:0:0:0: Attached scsi generic sg0 type 0
[   38.663662] sd 0:0:0:0: [sda] 30679040 512-byte logical blocks: (15.7 GB/14.6 GiB)
[   38.673145] sd 0:0:0:0: [sda] Write Protect is off
[   38.677862] sd 0:0:0:0: [sda] Mode Sense: 0b 00 00 08
[   38.684026] sd 0:0:0:0: [sda] No Caching mode page found
[   38.689257] sd 0:0:0:0: [sda] Assuming drive cache: write through
[   38.703539]  sda: sda1 sda2
[   38.715870] sd 0:0:0:0: [sda] Attached SCSI removable disk

To connect it to micro AB connector (J19), a cable like the one shown in the following picture has been used [1].

USB cable used to connect memory stick

Once mounted (at mnt/sda1 in the example), the memory stick can be accessed by regular commands:

root@bora:~# mount /dev/sda1 /mnt/sda1/
root@bora:~# mount on / type nfs (rw,relatime,vers=2,rsize=4096,wsize=4096,namlen=255,hard,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=,mountvers=1,mountproto=tcp,local_lock=all,addr=
devtmpfs on /dev type devtmpfs (rw,relatime,size=507916k,nr_inodes=126979,mode=755)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /var/volatile type tmpfs (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
/dev/sda1 on /mnt/sda1 type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
root@bora:~# time cp LibreOffice_4.1.1_Win_x86.msi /mnt/sda1/

real    0m25.114s
user    0m0.010s
sys     0m4.070s
root@bora:~# umount /mnt/sda1/
root@bora:~# mount /dev/sda1 /mnt/sda1/
root@bora:~# md5sum LibreOffice_4.1.1_Win_x86.msi /mnt/sda1/LibreOffice_4.1.1_Win_x86.msi
4fa047c0590097ce201f49655365d772  LibreOffice_4.1.1_Win_x86.msi
4fa047c0590097ce201f49655365d772  /mnt/sda1/LibreOffice_4.1.1_Win_x86.msi

[1] This type of cables forces the ID signal of the USB port to be connected to ground, selecting the host mode on SBC Lynx side.

Device mode[edit | edit source]

The following examples shows how to configure Bora/BoraEVB or BoraX/BoraXEVB to act as a mass storage device.

First, a local file named mass is created to emulate a mass storage disk that is populated with a file named file.txt:

root@bora:~# dd if=/dev/zero of=mass count=16 bs=1M
16+0 records in
16+0 records out
root@bora:~# mkfs.ext3 mass
mke2fs 1.42.9 (28-Dec-2013)
mass is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
4096 inodes, 16384 blocks
819 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=16777216
2 block groups
8192 blocks per group, 8192 fragments per group
2048 inodes per group
Superblock backups stored on blocks:

Allocating group tables: done
Writing inode tables: done
Creating journal (1024 blocks): done
Writing superblocks and filesystem accounting information: done
root@bora:~# mkdir loop
root@bora:~# mount -o loop mass loop
[   92.316783] kjournald starting.  Commit interval 5 seconds
[   92.316901] EXT3-fs (loop0): using internal journal
[   92.316908] EXT3-fs (loop0): mounted filesystem with writeback data mode
root@bora:~# echo dummy > loop/file.txt
root@bora:~# umount loop

Then the proper drivers are loaded on target side:

root@bora:~# modprobe g_mass_storage file=/home/root/mass
[  209.058156] Number of LUNs=8
[  209.061005] Mass Storage Function, version: 2009/09/11
[  209.066085] LUN: removable file: (no medium)
[  209.070349] Number of LUNs=1
[  209.073781] LUN: file: /home/root/mass
[  209.077444] Number of LUNs=1
[  209.080452] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11
[  209.087381] g_mass_storage gadget: userspace failed to provide iSerialNumber
[  209.094393] g_mass_storage gadget: g_mass_storage ready
[  209.099572] zynq-udc: bind to driver g_mass_storage

Last, BoraEVB (or BoraXEVB) is connected to a Linux PC with a USB cable like this one:

USB cable used to connect BoraXEVB to PC

On PC side, BoraEVB (or BoraXEVB) is detected as a common USB mass storage device.

CAN[edit | edit source]

See CAN Pinout page and BXELK Vivado project for more details.

Physical device Processor's resource Connector Type Notes
CAN BUS can0 J24 differential CAN bus

The following commands can be issued from command line in order to send and receive CAN frames:

root@bora:~# dmesg | grep -i can
[    0.643798] CAN device driver interface
[    0.997787] can: controller area network core (rev 20120528 abi 9)
[    1.008392] can: raw protocol (rev 20120528)
[    1.012661] can: broadcast manager protocol (rev 20120528 t)
[    1.018294] can: netlink gateway (rev 20130117) max_hops=1
root@bora:~# canconfig can0 stop
can0 state: STOPPED
root@bora:~# canconfig can0 bitrate 500000
can0 bitrate: 500000, sample-point: 0.875
root@bora:~# canconfig can0 start
can0 state: ERROR-ACTIVE
root@bora:~# cansend can0 -i 0x77 0x33 0x88 0x33 0x88 0x33 0x88 0x33
interface = can0, family = 29, type = 3, proto = 1
root@bora:~# cansend can0 -i 0x77 0x33 0x88 0x33 0x88 0x33 0x88 0x33
interface = can0, family = 29, type = 3, proto = 1
root@bora:~# cansend can0 -i 0x77 0x33 0x88 0x33 0x88 0x33 0x88 0x33
interface = can0, family = 29, type = 3, proto = 1
root@bora:~# candump can0
interface = can0, family = 29, type = 3, proto = 1
<0x100> [8] 12 34 56 78 9a bc de ff
<0x100> [8] 12 34 56 78 9a bc de ff
<0x100> [8] 12 34 56 78 9a bc de ff
<0x100> [8] 12 34 56 78 9a bc de ff
<0x100> [8] 12 34 56 78 9a bc de ff

In case canutils package is missing, user can install it directly from DAVE's BORA package server using smart update && smart install canutils commands:

root@bora:~# smart update
Updating cache...               ######################################## [100%]

Fetching information for 'all'...
repomd.xml                      ######################################## [ 50%]
Channels have 393 new packages.
Saving cache...

root@bora:~# smart install canutils
Loading cache...
Updating cache...               ######################################## [100%]

Computing transaction...

Installing packages (2):

27.8kB of package files are needed. 46.8kB will be used.

Confirm changes? (Y/n): y


See Advanced_use_of_Yocto_build_system_(BELK/BXELK) for more information about using Yocto packages and smart

UART0[edit | edit source]

UART0 is a spare UART device available on the JP17 PMOD connector. This device is routed through the PL. See BXELK Vivado project for more details.

Physical device Processor's resource Connector Type Linux device file Notes
UART0 UART0 JP17 2-wire LVTTL UART /dev/ttyPS1

Temperature sensors[edit | edit source]

Bora SOM has a TMP421AIDCN temperature sensor onboard.

The following commands can be issued from command line in order to get the SOM temperatue:

  • read the PCB temperature
root@bora:~# cat /sys/devices/soc0/amba/e0004000.i2c/i2c-0/0-004f/hwmon/hwmon1/temp1_input

the returned value has to be divided by 1000 for a °C temperature

  • read the CPU temperature
root@bora:~# cat /sys/devices/soc0/amba/e0004000.i2c/i2c-0/0-004f/hwmon/hwmon1/temp2_input

the returned value has to be divided by 1000 for a °C temperature

Moreover, the SOC has an internal temperature sensor device which can be read using the following shell script:

root@bora:~# cat

# Tcpu
TEMP_RAW=`cat /sys/devices/soc0/amba/f8007100.adc/iio:device0/in_temp0_raw`
TEMP_OFFSET=`cat /sys/devices/soc0/amba/f8007100.adc/iio:device0/in_temp0_offset`
TEMP_SCALE=`cat /sys/devices/soc0/amba/f8007100.adc/iio:device0/in_temp0_scale`
TEMP=`awk "BEGIN {print (($TEMP_RAW+$TEMP_OFFSET)*$TEMP_SCALE)/1000}"`

echo "Cpu Temp: ${TEMP}"

Power consumption[edit | edit source]

Power consumption measure can be performed accessing the INA226 device connected to the I2C bus in the BoraEVB (U3). The following commands can be saved as a shell script (e.g. read_power_values) and run to collect the measurements data:

root@bora:~# cat


IN1=`cat $path_dev/in1_input`
IN0=`cat $path_dev/in0_input`
VOLTAGE=`awk "BEGIN {print ($IN1-$IN0)/1000}"`
CURRENT=`cat $path_dev/curr1_input`
CURRENT=`awk "BEGIN {print ($CURRENT)/1000}"`
POWER=`cat $path_dev/power1_input`
POWER=`awk "BEGIN {print ($POWER)/1000000}"`
echo "Voltage: ${VOLTAGE}, Current: ${CURRENT}, Power:${POWER}"
root@bora:~# ./
Voltage: 3.308, Current: 0.64, Power:2.175