dt-bindings: interrupt-controller: Convert fsl,mpic-msi to YAML

As part of a larger effort to bring various PowerPC-related bindings
into the YAML world, this patch converts msi-pic.txt to YAML and moves
it into the bindings/interrupt-controller/ directory. The conversion may
necessarily be a bit hard to read because the binding is quite verbose.

Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
Link: https://lore.kernel.org/r/20250611-msipic-yaml-v2-1-f2e174c48802@posteo.net
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
This commit is contained in:
J. Neuschäfer
2025-06-11 11:42:09 +02:00
committed by Rob Herring (Arm)
parent de13141516
commit 98f79c729d
2 changed files with 161 additions and 111 deletions

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@@ -0,0 +1,161 @@
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/interrupt-controller/fsl,mpic-msi.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Freescale MSI interrupt controller
description: |
The Freescale hypervisor and msi-address-64
-------------------------------------------
Normally, PCI devices have access to all of CCSR via an ATMU mapping. The
Freescale MSI driver calculates the address of MSIIR (in the MSI register
block) and sets that address as the MSI message address.
In a virtualized environment, the hypervisor may need to create an IOMMU
mapping for MSIIR. The Freescale ePAPR hypervisor has this requirement
because of hardware limitations of the Peripheral Access Management Unit
(PAMU), which is currently the only IOMMU that the hypervisor supports.
The ATMU is programmed with the guest physical address, and the PAMU
intercepts transactions and reroutes them to the true physical address.
In the PAMU, each PCI controller is given only one primary window. The
PAMU restricts DMA operations so that they can only occur within a window.
Because PCI devices must be able to DMA to memory, the primary window must
be used to cover all of the guest's memory space.
PAMU primary windows can be divided into 256 subwindows, and each
subwindow can have its own address mapping ("guest physical" to "true
physical"). However, each subwindow has to have the same alignment, which
means they cannot be located at just any address. Because of these
restrictions, it is usually impossible to create a 4KB subwindow that
covers MSIIR where it's normally located.
Therefore, the hypervisor has to create a subwindow inside the same
primary window used for memory, but mapped to the MSIR block (where MSIIR
lives). The first subwindow after the end of guest memory is used for
this. The address specified in the msi-address-64 property is the PCI
address of MSIIR. The hypervisor configures the PAMU to map that address to
the true physical address of MSIIR.
maintainers:
- J. Neuschäfer <j.ne@posteo.net>
properties:
compatible:
oneOf:
- enum:
- fsl,mpic-msi
- fsl,mpic-msi-v4.3
- fsl,ipic-msi
- fsl,vmpic-msi
- fsl,vmpic-msi-v4.3
- items:
- enum:
- fsl,mpc8572-msi
- fsl,mpc8610-msi
- fsl,mpc8641-msi
- const: fsl,mpic-msi
reg:
minItems: 1
items:
- description: Address and length of the shared message interrupt
register set
- description: Address of aliased MSIIR or MSIIR1 register for platforms
that have such an alias. If using MSIIR1, the second region must be
added because different MSI group has different MSIIR1 offset.
interrupts:
minItems: 1
maxItems: 16
description:
Each one of the interrupts here is one entry per 32 MSIs, and routed to
the host interrupt controller. The interrupts should be set as edge
sensitive. If msi-available-ranges is present, only the interrupts that
correspond to available ranges shall be present.
msi-available-ranges:
$ref: /schemas/types.yaml#/definitions/uint32-matrix
items:
items:
- description: First MSI interrupt in this range
- description: Number of MSI interrupts in this range
description:
Define which MSI interrupt can be used in the 256 MSI interrupts.
If not specified, all the MSI interrupts can be used.
Each available range must begin and end on a multiple of 32 (i.e. no
splitting an individual MSI register or the associated PIC interrupt).
msi-address-64:
$ref: /schemas/types.yaml#/definitions/uint64
description:
64-bit PCI address of the MSIIR register. The MSIIR register is used for
MSI messaging. The address of MSIIR in PCI address space is the MSI
message address.
This property may be used in virtualized environments where the hypervisor
has created an alternate mapping for the MSIR block. See the top-level
description for an explanation.
required:
- compatible
- reg
- interrupts
allOf:
- if:
properties:
compatible:
contains:
enum:
- fsl,mpic-msi-v4.3
- fsl,vmpic-msi-v4.3
then:
properties:
interrupts:
minItems: 16
description:
Version 4.3 implies that there are 16 shared interrupts, and they
are configured through MSIIR1.
# MPIC v4.3 does not support this property because the 32 interrupts of
# an individual register are not continuous when using MSIIR1.
msi-available-ranges: false
reg:
minItems: 2
else:
properties:
interrupts:
maxItems: 8
description:
In versions before 4.3, only 8 shared interrupts are available, and
they are configured through MSIIR.
unevaluatedProperties: false
examples:
- |
msi@41600 {
compatible = "fsl,mpc8610-msi", "fsl,mpic-msi";
reg = <0x41600 0x80>;
msi-available-ranges = <0 0x100>;
interrupts = <0xe0 0>, <0xe1 0>, <0xe2 0>, <0xe3 0>,
<0xe4 0>, <0xe5 0>, <0xe6 0>, <0xe7 0>;
};
- |
msi@41600 {
compatible = "fsl,mpic-msi-v4.3";
reg = <0x41600 0x200>, <0x44148 4>;
interrupts = <0xe0 0 0 0>, <0xe1 0 0 0>, <0xe2 0 0 0>, <0xe3 0 0 0>,
<0xe4 0 0 0>, <0xe5 0 0 0>, <0xe6 0 0 0>, <0xe7 0 0 0>,
<0x100 0 0 0>, <0x101 0 0 0>, <0x102 0 0 0>, <0x103 0 0 0>,
<0x104 0 0 0>, <0x105 0 0 0>, <0x106 0 0 0>, <0x107 0 0 0>;
};
...

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* Freescale MSI interrupt controller
Required properties:
- compatible : compatible list, may contain one or two entries
The first is "fsl,CHIP-msi", where CHIP is the processor(mpc8610, mpc8572,
etc.) and the second is "fsl,mpic-msi" or "fsl,ipic-msi" or
"fsl,mpic-msi-v4.3" depending on the parent type and version. If mpic
version is 4.3, the number of MSI registers is increased to 16, MSIIR1 is
provided to access these 16 registers, and compatible "fsl,mpic-msi-v4.3"
should be used. The first entry is optional; the second entry is
required.
- reg : It may contain one or two regions. The first region should contain
the address and the length of the shared message interrupt register set.
The second region should contain the address of aliased MSIIR or MSIIR1
register for platforms that have such an alias, if using MSIIR1, the second
region must be added because different MSI group has different MSIIR1 offset.
- interrupts : each one of the interrupts here is one entry per 32 MSIs,
and routed to the host interrupt controller. the interrupts should
be set as edge sensitive. If msi-available-ranges is present, only
the interrupts that correspond to available ranges shall be present.
Optional properties:
- msi-available-ranges: use <start count> style section to define which
msi interrupt can be used in the 256 msi interrupts. This property is
optional, without this, all the MSI interrupts can be used.
Each available range must begin and end on a multiple of 32 (i.e.
no splitting an individual MSI register or the associated PIC interrupt).
MPIC v4.3 does not support this property because the 32 interrupts of an
individual register are not continuous when using MSIIR1.
- msi-address-64: 64-bit PCI address of the MSIIR register. The MSIIR register
is used for MSI messaging. The address of MSIIR in PCI address space is
the MSI message address.
This property may be used in virtualized environments where the hypervisor
has created an alternate mapping for the MSIR block. See below for an
explanation.
Example:
msi@41600 {
compatible = "fsl,mpc8610-msi", "fsl,mpic-msi";
reg = <0x41600 0x80>;
msi-available-ranges = <0 0x100>;
interrupts = <
0xe0 0
0xe1 0
0xe2 0
0xe3 0
0xe4 0
0xe5 0
0xe6 0
0xe7 0>;
interrupt-parent = <&mpic>;
};
msi@41600 {
compatible = "fsl,mpic-msi-v4.3";
reg = <0x41600 0x200 0x44148 4>;
interrupts = <
0xe0 0 0 0
0xe1 0 0 0
0xe2 0 0 0
0xe3 0 0 0
0xe4 0 0 0
0xe5 0 0 0
0xe6 0 0 0
0xe7 0 0 0
0x100 0 0 0
0x101 0 0 0
0x102 0 0 0
0x103 0 0 0
0x104 0 0 0
0x105 0 0 0
0x106 0 0 0
0x107 0 0 0>;
};
The Freescale hypervisor and msi-address-64
-------------------------------------------
Normally, PCI devices have access to all of CCSR via an ATMU mapping. The
Freescale MSI driver calculates the address of MSIIR (in the MSI register
block) and sets that address as the MSI message address.
In a virtualized environment, the hypervisor may need to create an IOMMU
mapping for MSIIR. The Freescale ePAPR hypervisor has this requirement
because of hardware limitations of the Peripheral Access Management Unit
(PAMU), which is currently the only IOMMU that the hypervisor supports.
The ATMU is programmed with the guest physical address, and the PAMU
intercepts transactions and reroutes them to the true physical address.
In the PAMU, each PCI controller is given only one primary window. The
PAMU restricts DMA operations so that they can only occur within a window.
Because PCI devices must be able to DMA to memory, the primary window must
be used to cover all of the guest's memory space.
PAMU primary windows can be divided into 256 subwindows, and each
subwindow can have its own address mapping ("guest physical" to "true
physical"). However, each subwindow has to have the same alignment, which
means they cannot be located at just any address. Because of these
restrictions, it is usually impossible to create a 4KB subwindow that
covers MSIIR where it's normally located.
Therefore, the hypervisor has to create a subwindow inside the same
primary window used for memory, but mapped to the MSIR block (where MSIIR
lives). The first subwindow after the end of guest memory is used for
this. The address specified in the msi-address-64 property is the PCI
address of MSIIR. The hypervisor configures the PAMU to map that address to
the true physical address of MSIIR.