linux - How can I get the corresponding MSI message in an interrupt? -


we using fpga on pcie card. able reserve proper resources , msi interrupt fires correctly. problem discerning interrupt sources from: linux driver receives single msi interrupt different interrupt sources fpga. therefore fpga guys sending reason coded in msi message on bus.

questions:

  1. is there possibility access message in order information out of frame in isr? (i know check fpga's interrupt status register, using msi message more elegant , avoid additional bus access.)
  2. if 1 not possible, switching msi-x solve problem, information directly? (i know msi-x preferred solution, fpga guys specified msi)

thank help!

hopefully have got answer need now, attempt contribute based on understanding of msi in the windows driver, since pcie 2.2 standard behavior , should not different. writing windows pcie driver handle msi interrupts originating ti dm8168 configured pcie endpoint.

when fpga device signals regular (non msi-x) msi interrupt, not send 'message' in sense data structure must filled , transmitted somewhere. msi achieved having fpga write data word value 1 specific memory location shared on pcie between host , device. particular memory location , data value must written selected host's bus manager, can't arbitrary value.

a pointer msi memory location , specific, pre-defined data value use set bus manager in pcie config space, device , host can both see them. msi memory location physical bus address, must translated virtual address space both on device , host.

the maximum number of messages regular (non msi-x) msi can support must integral power of 2 maximum of 32 (i.e. 1, 2, 4, 8, 16, 32). example if fpga supports 8 messages, copy data value (from pcie config space) , set lowest 3 bits indicate messageid number (0-7), , write new value msi pointer location. if fpga supports 16 messages, must modify lower 4 bits of data value indicate messageid number (0-15). higher bits of data value must not changed.

on receiving end in isr, check same lowest bits see msi signaled. there no other data or ack associated msi itself; further data implementation-specific , must read memory locations or registers agreed between , hardware team. in windows wdf framework drivers, messageid value masked , provided parameter evtinterruptisr callback function. i'm sure different in linux.

i'm bit late on response, might useful in future else crossing topic did in last few weeks.


Comments

Post a Comment

Popular posts from this blog

jquery - How can I dynamically add a browser tab? -

since using iframes house external pages are, accounts "not preferred method" , disallowed sites (flickr, one), want dynamically generate browser tabs. e.g., when user submits form, want dynamically generate tab on browser in response submitted. e.g., might want add new tab url like: http://www.bigsurgarrapata.com/contact how in jquery? you want form target attribute action attribute. http://www.w3schools.com/tags/att_form_target.asp browsers have ultimate control on result of target attribute open new tab value of _blank. <form action="contact_submit.php" target="_blank" method="post">
Read more

keyboard - C++ GetAsyncKeyState alternative -

i using windows.h library's getasynckeystate function define key pushed on keyboard . here program returns int value of pushed key example. #include <iostream> #include <windows.h> using namespace std; int main (){ char i; for(i=8;i<190;i++){ if(getasynckeystate(i)== -32767){ cout<<int (i)<<endl; } } return 0; } but trying make opengl simple game , function appeared slow . there function not need cycle 180 times , if statement . thanks you're trying make opengl game, you're going use glfw. if that's case can away using glfwgetkey() such: if (glfwgetkey(glfw_key_up) == glfw_press) {...} if (glfwgetkey(glfw_key_down) == glfw_press) {...} that method nicely explained in tutorial 6 opengl-tutorial.org . should start first tutorial of beginners tutorials , later intermediate tutorials . if you're going make win32 window can listen wm_keydown or wm_keyup messages , virtua...
Read more

android - java.net.UnknownHostException(Unable to resolve host “URL”: No address associated with hostname) -

i developing app testing asp.net webservice in android.for simple webservice adding 2 numbers used.where numbers passed parameters.the result in dialogue.the webserver works in local. when application runs following result exception.i provided internet permission in manifest. java.net.unknownhostexception(unable resolve host “ http://url.com/ ”: no address associated hostname) my code given below main activity public static string rslt=""; /** called when activity first created. */ @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); button b1=(button)findviewbyid(r.id.button1); final alertdialog ad=new alertdialog.builder(this).create(); b1.setonclicklistener(new onclicklistener() { @override public void onclick(view arg0) { // todo auto-generated method stub try { ...
Read more