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RTOS: PCIe inbound write/read detection

Ilya Afanasiev
Prodigy 210 points

Tool/software: TI-RTOS

Hello!

We use the am572x evm as PCIe EP with TI-RTOS on the board. Host is linux OS.

I init one inbound region in match mode BAR.

How am572x can detect that the host driver write to/read form inbound region?

  • 0
    TI__Guru**** 393215 points
    The RTOS team have been notified. They will respond here, but there may be a delay due to the holiday period.
  • 0 in reply to Biser Gatchev-XID
    TI__Guru* 95265 points
    Hi,

    For AM572x, you can use polling menthod to determine if the host driver wrote something to their inbound memory region.

    For both read and write cases, the host can send an interrupt to the AM572x to notify that.

    Regards, Eric
  • 0 in reply to lding
    Prodigy 210 points
    Hi,
    Thank you for quick reply.
    How the host can send an interrupt to the am572x?
  • 0 in reply to lding
    Prodigy 210 points

    Hi! I really want to know how the host can send an interrupt to the am572x :-)

  • 0 in reply to Ilya Afanasiev
    TI__Guru* 95265 points
    llya,

    Sorry I missed your previous post. In your setup the AM572x is the PCIE EP, interrupt (legacy or MSI)can only be sent from PCIE EP to RC by PCIE specification, and this is true from our AM572x TRM 24.9.4.6.

    The way to send an interrupt from PCIE RC to EP can be done in another way (not a real PCIE interrupt):
    - You map another periphral's (e.g. GPIO) memory space of AM572x EP into host via PCIE, so from the Linux host side you will be able to access it
    - On the AM572x side, you configure that periphral's interrupt to CPU (a15, dsp or m4)
    - On the Linux host you access EP's periphral device via PCIE to generate an interrupt

    So this is not a PCIE interrupt, but a periphral's interrupt to CPU generated from host side via PCIE.

    Regards, Eric