Fix Shepherd Device Tree Drivers

Original DT-Driver from shp v1 fails to work with 4.19 or newer.

Device Tree Versions

• v4.14.x https://github.com/beagleboard/BeagleBoard-DeviceTrees/commit/4a9c0a652f58090491319d27dac4bf76da7d6086

• v4.19.x https://github.com/beagleboard/BeagleBoard-DeviceTrees/commit/af07ef77cc6f8f94568a4c238cc6d41fb8c81931

• v5.4.x https://github.com/beagleboard/BeagleBoard-DeviceTrees/commit/26b4c9fea3ff919835ba27393d5781ca4dd0923f

• overlays: https://github.com/RobertCNelson/bb.org-overlays/tree/master/src/arm

Changes to reference DT-overlays

• compatible with v4.14.x: “ti,beaglebone”, “ti,beaglebone-black”

• newer dts files only speak of “ti,am335x-bone-black”, “ti,am335x-bone-green”, “ti,am335x-bone”, “ti,am33xx”

• pinctrl-single,pins

  • shprd: 0x034 0x06 /* P8.11, pr1_pru0_pru_r30_15 */

  • bbuniv: AM33XX_IOPAD(0x0834, PIN_OUTPUT | INPUT_EN | MUX_MODE6)

• exclusive-use seems fine

• target pruss overlay ⇾ fine

• overlay is not announcing itself in fragment@0

Shepherd Firmware

• make && sudo make install in device-tree sub-folder

• install in /lib/firmware/

• check status in /proc/device-tree/chosen/overlays/

  • or via: sudo /opt/scripts/tools/version.sh | grep UBOOT

Workflow

cd ~/
git clone https://github.com/nes-lab/shepherd
cd shepherd/software/firmware/device-tree
make && sudo make install
# add to /boot/uEnv.txt
# check after reboot if loaded
sudo /opt/scripts/tools/version.sh | grep UBOOT

Backup Image

sudo mount /dev/sda1 /media
sudo dd if=/dev/mmcblk1 of=/media/mmc_s0_v4.19.94_bootstrap_apt.img
sudo umount /media

# alternative to local sd-card
sudo dd if=/dev/mmcblk1 of=/dev/mmcblk0

Delete Kernel-Image on MMC

sudo mount /dev/mmcblk1p1 /media
cd /media/lib/modules/.../extra
sudo rm shepherd.ko

# better way: do not load module on startup
sudo nano /etc/modules