Getting BBB Ready for BeagleWire

1) Flashing BeagleBone Black With New Image

First of all download this image from beagleboard site: AM3358 Debian 10.3 2020-04-06 4GB SD IoT
Using this tool flash the SD_card: balena-etcher

Booting from SD Card:

GPMC has been used to transfer the data between FPGA cape and ARM.
GPMC and EMMC pins are multiplexed, so if one needs to use GPMC then BBB should be booted from SD Card Only.
For details steps once can follow below tutorials:
1. Derekmolly's tutorial

2) Upgrade the software on your Beagle

Connect BeagleBoard to the internet

For detailed steps you can follow this: Get connected to the Internet

Update the boot-up scripts and Linux kernel

cd /opt/scripts
git pull
sudo tools/update_kernel.sh
sudo shutdown -r now
  

Update distribution components

sudo apt update
sudo apt upgrade
  

Addition References: Upgrade the software on your Beagle

3) Installing Linux Headers and Flashrom

sudo apt install linux-headers-$(uname -r) #Needed to directly program FPGA
sudo apt-get install flashrom #Needed to program FPGA using spi method
  

4) BeagleWire Software:

 # Recommended to clone both on host and BBB
 git clone https://github.com/BeagleWire/BeagleWire 
 git checkout testing   
  

5) Device Tree Overlay and uEnv.txt:

Device Tree Overlay is required for initializing the spidev to program the FPGA and gpmc to communicate with FPGA for data transfer.

git clone https://github.com/BeagleWire/BeagleBoard-DeviceTrees
cd BeagleBoard-DeviceTrees
make
sudo cp src/arm/overlays/BW-ICE40Cape-00A0.dtbo /lib/firmware
sudo cp src/arm/overlays/BW-ICE40Cape-00A0_LKM.dtbo /lib/firmware

#  Create dtb backup:
sudo cp /boot/dtbs/4.19*/am335x-boneblack-uboot-univ.dtb am335x-boneblack-uboot-univ.dtb.backup

# Install the new dtb:
cd BeagleBoard-DeviceTrees
sudo cp src/arm/am335x-boneblack-uboot-univ.dtb /boot/dtbs/4.19*/
  

Some of the things needs to be disabled in uEnv.txt to run the FPGA:
Find the following part: (Disabling boot from emmc to use GPMC on the FPGA Cape)

enable_uboot_cape_universal=1 #Keep Cape Universal Enabled
#disable_uboot_overlay_emmc=1
#disable_uboot_overlay_video=1
#disable_uboot_overlay_audio=1
#disable_uboot_overlay_wireless=1
#disable_uboot_overlay_adc=1
  

Instead add this

enable_uboot_cape_universal=1 #Keep Cape Universal Enabled
disable_uboot_overlay_emmc=1
disable_uboot_overlay_video=1
disable_uboot_overlay_audio=1
disable_uboot_overlay_wireless=1
disable_uboot_overlay_adc=1
  

Sample uEnv.txt: reference

6) Writing EEPROM configuration contents

BeagleWire cape has a EEPROM memory, so that the BBB device overlay is automatically loaded up on each boot up.
EEPROM contents and loading script are located in BeagleWire software repository.
So once we program the eeprom, then we don't have to explicitly add overlay info in uEnv.txt at any addr4
If BW-ICE40Cape-00A0.dtbo is present in /lib/firmware then it will be automatically loaded.

cd BeagleWire/EEPROM_Cape/
sudo ./load_eeprom.sh
  

7) Programming BeagleWire:

There are two ways to program the FPGA:
1. First we program the onboard SPI flash, after reset the fpga is booted from spi flash. Even after power cut the program is retain. (Overlay: BW_ICE40Cape_00A0.dtbo)
2. Directly programmnig the FPGA using custom LKM, in this method FPGA is directly programmed with bitstream and after power cut program is no longer exist. (Overlay: BW_ICE40Cape_00A0_LKM.dtbo)
First of all add following lines in .bashrc at the end, so that those scripts can be run from anywhere.
vim /home/debian/.bashrc

# To run beaglewire script from anywhere
 export PATH=$PATH:/home/debian/BeagleWire/load_fw
  

Build LKM and make executable the load_fw directory beforehand:

cd BeagleWire/bridge_lib
make #Build the memmap and other bridge files
cd BeagleWire/load_fw
make #Builds the lkm
chmod +x * #Make the scripts and spi test executable
  

There are several ways for programming bitstream into BeagleWire:

1) Flashing the sram on beaglewire with bitstream: (simplest way)

    sudo su
    source .bashrc 
    bw-spi.sh <bin file to program>
    #Example: bw-spi.sh blink.bin
  

2) LKM module with the ice40-spi kernel driver:

For this you need to load following DTS file into uEnv.txt

    sudo vim /boot/uEnv.txt
    
    #Add this overlay line at addr0 place:
    #If we had added the overlay at addr4, bbb automatically will add BW-ICE40Cape-00A0.dtbo overlay
    #So to override that file we need to add this at addr0
    
    uboot_overlay_addr0=/lib/firmware/BW-ICE40Cape-00A0_LKM.dtbo 
    
    #Disable the cape universal
    #enable_uboot_cape_universal = 1

    #Reboot after this
  

bw-prog.sh blink.bin
Using this way one can program any bitstream directly to the FPGA via ice40-spi kernel driver and LKM module.