• How to get a “Hello World” (DMA) on PicoEVB
• Preliminaries
• Generating the Bitstream
• Flashing the ?ROM?
• Testing DMA (i.e., the actual “Hello World”)
• Final Product
• Useful Links

How to get a “Hello World” (DMA) on PicoEVB

Preliminaries

1. Download Vivado and etc. Note only tested with 2021.1.1 (make sure you download drivers for Artix 7 boards)
2. Download/build https://github.com/RHSResearchLLC/xvcd/
3. Download/install/build (https://github.com/Xilinx/dma_ip_drivers/) using cd XDMA/linux-kernel/xdma && make install

   1. If you get an error regarding

       At main.c:160:
       - SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:69
       - SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:76
       sign-file: certs/signing_key.pem: No such file or directory
         DEPMOD  /lib/modules/5.13.0-27-generic
       Warning: modules_install: missing 'System.map' file. Skipping depmod.
      

      then you need to generate certs in /lib/modules/$(uname -r)/build/certs (taken from https://superuser.com/a/1322832)

      1. create x509.genkey

          [ req ]
          default_bits = 4096
          distinguished_name = req_distinguished_name
          prompt = no
          string_mask = utf8only
          x509_extensions = myexts
                     
          [ req_distinguished_name ]
          CN = Modules
                     
          [ myexts ]
          basicConstraints = critical,CA:FALSE
          keyUsage = digitalSignature
          subjectKeyIdentifier = hash
          authorityKeyIdentifier = keyid
         

      2. run openssl req -new -nodes -utf8 -sha512 -days 36500 -batch -x509 -config x509.genkey -outform DER -out signing_key.x509 -keyout signing_key.pem
      3. Copy signing_key.x509 and signing_key.pem to /lib/modules/$(uname -r)/build/certs (if you didn’t already just generate there)

Generating the Bitstream

1. Open the PicoEVB project in Vivado, through PicoEVB/Sample-Projects/Project-0/FPGA/picoevb.xpr
2. Hit Generate Bitstream (under Program and Debug bottom left).

   1. If you get errors that look like

      

      which are super confusing because those modules do exist (i.e., as directories in the source tree) you might have to “Upgrade IP” for some module. Find the top level whatever in the sources tab and click Report IP Status

      

      which should pull a thing like this at the bottom of the screen

      

      click Upgrade Selected you should get a pop-up like this; if not you right click the same top-level spot and select Generate Output Products

      

   2. Once all of that is done you can click Generate Bitstream and it should work 🤞

3. Once the bitstream is generated you’ll get a pop-up that lets you Generate Memory Configuration File. Following the listed command at README.md

    write_cfgmem -force -format mcs -size 4 -interface SPIx4 \
    -loadbit {up 0x00000000 "./picoevb.runs/impl_1/project_bd_wrapper.bit" } \
    -file "../mcs/proj0.mcs"
   

   you should select

   

Flashing the ?ROM?

1. Run xvcd (that you setup here) using sudo ./xvcd -P 0x6015 (no clue why the port needs to be in hex)

2. Back in Vivado, connect the JTAG “virtual” cable by opening hardware manager

   

   clicking the connect icon

   

   then right clicking localhost and clicking Add Xilinx Virtual Cable (this is will make use of xvcd from above). It might take a while…

   

3. Once you’ve done all that you should be able to click Program Device (same bottom left)

Testing DMA (i.e., the actual “Hello World”)

1. Load the kernel module (using tests/load_driver.sh, that you setup here)

   1. If you get

       Loading xdma driver...
       Error: The Kernel module installed correctly, but no devices were recognized.
        FAILED
      

      then check dmesg for something like

       [13941.276029] xdma:map_bars: Failed to detect XDMA config BAR
       [13941.306054] xdma:probe_one: pdev 0x00000000ad7d31b7, err -22.
       [13941.306063] xdma:xpdev_free: xpdev 0x00000000648e3236, destroy_interfaces, xdev 0x0000000000000000.
       [13941.306065] xdma:xpdev_free: xpdev 0x00000000648e3236, xdev 0x0000000000000000 xdma_device_close.
      

      which means you need to rescan the pci bus using

       $ echo 1 > /sys/bus/pci/devices/0000\:03\:00.0/remove
       $ echo 1 > /sys/bus/pci/rescan
      

      (from https://github.com/RHSResearchLLC/PicoEVB/issues/12)

2. Run [Sample-Projects/Project-0/Host/dma-test.py](https://github.com/RHSResearchLLC/PicoEVB/blob/0319d34e25f21c830fdf7e81867bafb07c7913af/Sample-Projects/Project-0/Host/dma-test.py) and you should get something like

    root@maksim-Inspiron-5577:/home/maksim/dev_projects/PicoEVB/Sample-Projects/Project-0/Host# python3 dma-test.py 
    Sent in 0.10848045349121094 milliseconds (37.75795425054945 MBPS)
    Received in 0.09036064147949219 milliseconds (45.32947014248021 MBPS)
    OK
   

   Note that you need to run this as root because it writes/reads directly to from /dev/xdma0_*.

   1. If you get an error like

       Traceback (most recent call last):
         File "/home/maksim/dev_projects/PicoEVB/Sample-Projects/Project-0/Host/dma-test.py", line 50, in <module>
           main()
         File "/home/maksim/dev_projects/PicoEVB/Sample-Projects/Project-0/Host/dma-test.py", line 13, in main
           fd_h2c = os.open("/dev/xdma/card0/h2c0", os.O_WRONLY)
       FileNotFoundError: [Errno 2] No such file or directory: '/dev/xdma/card0/h2c0'
      

      then double check the path /dev/xdma/card0/h2c0; on my laptop the correct paths were /dev/xdma0_h2c_0.

Final Product

project_bd.pdf

Useful Links

1. https://github.com/RHSResearchLLC/PicoEVB
2. https://github.com/Xilinx/dma_ip_drivers/
3. https://github.com/NVIDIA/jetson-rdma-picoevb (this one was useful for getting oriented with flow via the scripts under fpga-picoevb)