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Adventurer
Adventurer
780 Views
Registered: ‎08-01-2018

Cannot start DMA channel

Hello,

 

     I am trying to read data using a v4l2 driver. I believe I have configured correctly the vdma parameters(width, height, stride, etc) as the VDMA hw expects.

     I see in examples from Xilinx SDK that other that frame parameters and enabling interrupts there is no much vdma configuration(using XAxiVdma API)  before writing/reading data.

    However after dmaengine_submit call I get the following error:

 

xilinx-vdma 43000000.dma: Cannot start channel 9f6dda10: 18831

 

    It would appear that some of the errors are EOL or SOF but I don't think it should be the case.

 

    What other settings should be configured before working with Xilinx VDMA?

 

Best regards,

         Mihaita

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4 Replies
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Adventurer
Adventurer
740 Views
Registered: ‎08-01-2018

Re: Cannot start DMA channel

Hello,

 

     Does anybody know possible reasons for getting DMA slave error: XILINX_DMA_DMASR_DMA_SLAVE_ERR ?

     It seems is the only DMA error I get that makes the channel halt(the others are maskable)

    In the  vdma IP UG fromXilinx it is stated  that the slave responds with SLVERR on memory map interface.

     How could I figure out exactly why that happens?

 

Thanks,

       Mihaita

   

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Voyager
Voyager
708 Views
Registered: ‎10-21-2015

Re: Cannot start DMA channel

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Adventurer
Adventurer
668 Views
Registered: ‎08-01-2018

Re: Cannot start DMA channel

Hi,

 

   Thanks for the advice. i tried that already but the vdmatest module is not loaded,. i have added in dts like the documnetion explains and vdma version is the same as the one in the driver, but the module is still not loaded.

 

Best regards,

         Mihaita

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Adventurer
Adventurer
650 Views
Registered: ‎08-01-2018

Re: Cannot start DMA channel

Hi,

 

     I do not know how to run the vdmatest client actually:

     I have the vdma node:

 

/sys/bus/platform/devices/amba_pl:vdmatest@0
/sys/devices/soc0/amba_pl/amba_pl:vdmatest@0
/sys/firmware/devicetree/base/amba_pl/vdmatest@0

 

    and looked at the vdmatest.c source but could not figure out how to run the test.

    Any suggestions?

 

Thanks,

        Mihaita

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