DMA irq ports cause python empty string dict lookup

[Recognition2]

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• PYNQ version (e.g. v2.5): v2.5
• Board name (e.g. Pynq-Z1): Pynq-Z2
• Pull request type (bug fix / new feature): -
• Pull request number: -
• Description: Bug in IRQ usage. Given a simple FIFO throughput setup, like this:

Given this setup, including the connection of the s2mm_introut and mm2s_introut pins to the IRQ_F2P using a Concat block, the pynq library will refuse to transmit any data over the DMA channels with the following error:

KeyError                                  Traceback (most recent call last)
<ipython-input-45-b53b94401f56> in <module>()
      1 import pynq.lib.dma
      2 
----> 3 dma_send = ol.axi_dma_ps_to_pl
      4 dma_recv = ol.axi_dma_pl_to_ps

/usr/local/lib/python3.6/dist-packages/pynq/overlay.py in __getattr__(self, key)
    335         """
    336         if self.is_loaded():
--> 337             return getattr(self._ip_map, key)
    338         else:
    339             raise RuntimeError("Overlay not currently loaded")

/usr/local/lib/python3.6/dist-packages/pynq/overlay.py in __getattr__(self, key)
    735         elif key in self._description['ip']:
    736             ipdescription = self._description['ip'][key]
--> 737             driver = ipdescription['driver'](ipdescription)
    738             setattr(self, key, driver)
    739             return driver

/usr/local/lib/python3.6/dist-packages/pynq/lib/dma.py in __init__(self, description, *args, **kwargs)
    188                                'has been deprecated and moved to '
    189                                'pynq.lib.deprecated')
--> 190         super().__init__(description=description)
    191 
    192         if 'parameters' in description and \

/usr/local/lib/python3.6/dist-packages/pynq/overlay.py in __init__(self, description)
    600             self._gpio = {}
    601         for interrupt, details in self._interrupts.items():
--> 602             setattr(self, interrupt, Interrupt(details['fullpath']))
    603         for gpio, entry in self._gpio.items():
    604             gpio_number = GPIO.get_gpio_pin(entry['index'])

/usr/local/lib/python3.6/dist-packages/pynq/interrupt.py in __init__(self, pinname)
     96         self.number = PL.interrupt_pins[pinname]['index']
     97         self.parent = weakref.ref(
---> 98             _InterruptController.get_controller(parentname))
     99         self.event = asyncio.Event()
    100         self.waiting = False

/usr/local/lib/python3.6/dist-packages/pynq/interrupt.py in get_controller(name)
    157             if con.name == name:
    158                 return con
--> 159         ret = _InterruptController(name)
    160         _InterruptController._controllers.append(ret)
    161         return ret

/usr/local/lib/python3.6/dist-packages/pynq/interrupt.py in __init__(self, name)
    175         """
    176         self.name = name
--> 177         self.mmio = MMIO(PL.ip_dict[name]['phys_addr'], 32)
    178         self.wait_handles = [[] for _ in range(32)]
    179         self.event_number = 0

KeyError: ''

This is caused by the interrupt pin being created in the static method _Interrupt.get_controller, more specifically, the parent of the interrupt being an empty string. This results in a lookup in ip_dict with an empty string as key, which fails. If I remove the interrupts from the block diagram (and from the ZYNQ7 PS) then this code does run, but does not do throughput. Instead, it always outputs dec0dee3, and I have no clue why.

This is using Vivado 2019.1, pynq 2.5, the PYNQ Z2 board, linux 4.14-xilinx-v2018.3.

[iapapistas]

Indeed I am facing the same error. Initially I found that adding an AXI interrupt controller between the PS7 and the AXI peripheral will solve this particular problem, however then a new error appears:

ValueError: Could not find UIO device for interrupt pin for IRQ number 0

Did you eventually find any workaround for the initial issue?

[archy-embedinn]

please check weather linux uio driver is setup and installed properly? $ls /dev/uio0 if its not present then you need to update the devicetree. or linux kernel module for uio driver etc.

[twaclaw]

Have a look at this entry:

https://forums.xilinx.com/t5/Embedded-Linux/A-key-error-when-I-am-trying-to-access-a-DMA-IP-on-PYNQ-Z1-board/td-p/847817

[mariodruiz]

For more than one interrupt you need to use an AXI Interrupt Controller

https://discuss.pynq.io/t/interrupt-error-on-using-two-vdma/2700/4

[schelleg]

I'll close this older issue for now ... please reopen on discuss.pynq.io as needed.