Merge branch 'postmerge' into for-linus

[karo-tx-linux.git] / Documentation / virtual / kvm / devices / mpic.txt

diff --git a/Documentation/virtual/kvm/devices/mpic.txt b/Documentation/virtual/kvm/devices/mpic.txt
index ce98e3264fa8bd7219f4a5d54ab79834910d95b5..8257397adc3cc18a0733f58ee7c5b8a89bb0dfbe 100644 (file)
--- a/Documentation/virtual/kvm/devices/mpic.txt
+++ b/Documentation/virtual/kvm/devices/mpic.txt
@@ -35,3 +35,19 @@ Groups:
 
     "attr" is the IRQ number.  IRQ numbers for standard sources are the
     byte offset of the relevant IVPR from EIVPR0, divided by 32.
+
+IRQ Routing:
+
+  The MPIC emulation supports IRQ routing. Only a single MPIC device can
+  be instantiated. Once that device has been created, it's available as
+  irqchip id 0.
+
+  This irqchip 0 has 256 interrupt pins, which expose the interrupts in
+  the main array of interrupt sources (a.k.a. "SRC" interrupts).
+
+  The numbering is the same as the MPIC device tree binding -- based on
+  the register offset from the beginning of the sources array, without
+  regard to any subdivisions in chip documentation such as "internal"
+  or "external" interrupts.
+
+  Access to non-SRC interrupts is not implemented through IRQ routing mechanisms.