Doubt on first access for PCIe device

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




Hi All,

I was referring Linux code for PCIe enumeration and I have one doubt w.r.t to very first operation that must be done on device.

Currently while scanning for device, we directly read vendor ID from device. But PCIE base specification "CB-PCI_Express_Base_4.0r0.7_November-11-2016.pdf" section 2.2.6.2 specifies that,

"Functions must capture the Bus and Device Numbers supplied with all Type 0 Configuration Write Requests completed by the Function and supply these numbers in the Bus and Device Number fields of the Requester ID for all Requests initiated by the Device/Function."

Here I am assuming, the completer ID will be device number and function number that will eventually programmed in to device. In that case, my question is, without first write, how read request(VENDOR ID read) is serviced/routed?

Sorry I am feeling bit confused, help will be appreciated.
--
Best wishes,
Abhijit Naik



[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux