lkml.org 
[lkml]   [2014]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v10 07/10] OF: Introduce helper function for getting PCI domain_nr
    >> OK. Sorry, I have one last question, because domain will be used to calculate the address used to
    >> access PCI hardware config registers. So if DTS file doesn't report the domain, how do we know
    >> we would access the right registers when we use the auto increment domain vaule ?
    >> Has there a mechanism to make sure system can access the correct registers by the domain ?
    >
    > I think you're referring to config access via ECAM (PCIe r3.0, sec
    > 7.2.2). In that case, I don't think the domain should be used to
    > compute the memory-mapped configuration address. Each host bridge is
    > in exactly one domain, and each host bridge has an associated ECAM
    > area base. The address calculation uses the bus number, device
    > number, function number, and register number to compute an offset into
    > the ECAM area.
    >
    > So as long as the DT tells you the ECAM information for each host
    > bridge, that should be sufficient. The domain number is then just a
    > Linux convenience and is not tied to the platform as it is on ia64.

    Hi Bjorn, you are right, thanks for your detailed explanation! :)

    Thanks!
    Yijing.

    >
    > Bjorn
    >
    > .
    >


    --
    Thanks!
    Yijing



    \
     
     \ /
      Last update: 2014-09-10 04:41    [W:2.483 / U:0.272 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site