summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/virtual/kvm/devices/mpic.txt
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/Documentation/virtual/kvm/devices/mpic.txt')
-rw-r--r--kernel/Documentation/virtual/kvm/devices/mpic.txt53
1 files changed, 53 insertions, 0 deletions
diff --git a/kernel/Documentation/virtual/kvm/devices/mpic.txt b/kernel/Documentation/virtual/kvm/devices/mpic.txt
new file mode 100644
index 000000000..8257397ad
--- /dev/null
+++ b/kernel/Documentation/virtual/kvm/devices/mpic.txt
@@ -0,0 +1,53 @@
+MPIC interrupt controller
+=========================
+
+Device types supported:
+ KVM_DEV_TYPE_FSL_MPIC_20 Freescale MPIC v2.0
+ KVM_DEV_TYPE_FSL_MPIC_42 Freescale MPIC v4.2
+
+Only one MPIC instance, of any type, may be instantiated. The created
+MPIC will act as the system interrupt controller, connecting to each
+vcpu's interrupt inputs.
+
+Groups:
+ KVM_DEV_MPIC_GRP_MISC
+ Attributes:
+ KVM_DEV_MPIC_BASE_ADDR (rw, 64-bit)
+ Base address of the 256 KiB MPIC register space. Must be
+ naturally aligned. A value of zero disables the mapping.
+ Reset value is zero.
+
+ KVM_DEV_MPIC_GRP_REGISTER (rw, 32-bit)
+ Access an MPIC register, as if the access were made from the guest.
+ "attr" is the byte offset into the MPIC register space. Accesses
+ must be 4-byte aligned.
+
+ MSIs may be signaled by using this attribute group to write
+ to the relevant MSIIR.
+
+ KVM_DEV_MPIC_GRP_IRQ_ACTIVE (rw, 32-bit)
+ IRQ input line for each standard openpic source. 0 is inactive and 1
+ is active, regardless of interrupt sense.
+
+ For edge-triggered interrupts: Writing 1 is considered an activating
+ edge, and writing 0 is ignored. Reading returns 1 if a previously
+ signaled edge has not been acknowledged, and 0 otherwise.
+
+ "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.