1.. SPDX-License-Identifier: GPL-2.0
2
3=========================
4MPIC interrupt controller
5=========================
6
7Device types supported:
8
9  - KVM_DEV_TYPE_FSL_MPIC_20     Freescale MPIC v2.0
10  - KVM_DEV_TYPE_FSL_MPIC_42     Freescale MPIC v4.2
11
12Only one MPIC instance, of any type, may be instantiated.  The created
13MPIC will act as the system interrupt controller, connecting to each
14vcpu's interrupt inputs.
15
16Groups:
17  KVM_DEV_MPIC_GRP_MISC
18   Attributes:
19
20    KVM_DEV_MPIC_BASE_ADDR (rw, 64-bit)
21      Base address of the 256 KiB MPIC register space.  Must be
22      naturally aligned.  A value of zero disables the mapping.
23      Reset value is zero.
24
25  KVM_DEV_MPIC_GRP_REGISTER (rw, 32-bit)
26    Access an MPIC register, as if the access were made from the guest.
27    "attr" is the byte offset into the MPIC register space.  Accesses
28    must be 4-byte aligned.
29
30    MSIs may be signaled by using this attribute group to write
31    to the relevant MSIIR.
32
33  KVM_DEV_MPIC_GRP_IRQ_ACTIVE (rw, 32-bit)
34    IRQ input line for each standard openpic source.  0 is inactive and 1
35    is active, regardless of interrupt sense.
36
37    For edge-triggered interrupts:  Writing 1 is considered an activating
38    edge, and writing 0 is ignored.  Reading returns 1 if a previously
39    signaled edge has not been acknowledged, and 0 otherwise.
40
41    "attr" is the IRQ number.  IRQ numbers for standard sources are the
42    byte offset of the relevant IVPR from EIVPR0, divided by 32.
43
44IRQ Routing:
45
46  The MPIC emulation supports IRQ routing. Only a single MPIC device can
47  be instantiated. Once that device has been created, it's available as
48  irqchip id 0.
49
50  This irqchip 0 has 256 interrupt pins, which expose the interrupts in
51  the main array of interrupt sources (a.k.a. "SRC" interrupts).
52
53  The numbering is the same as the MPIC device tree binding -- based on
54  the register offset from the beginning of the sources array, without
55  regard to any subdivisions in chip documentation such as "internal"
56  or "external" interrupts.
57
58  Access to non-SRC interrupts is not implemented through IRQ routing mechanisms.
59