Thread (9 messages) 9 messages, 3 authors, 2021-08-15

Re: [PATCH v3 1/2] dt-bindings: pci: Add DT bindings for apple,pcie

From: Rob Herring <robh@kernel.org>
Date: 2021-07-26 23:19:03
Also in: linux-devicetree, linux-pci, lkml

On Mon, Jul 26, 2021 at 10:32:00AM +0200, Mark Kettenis wrote:
quoted hunk ↗ jump to hunk
From: Mark Kettenis <redacted>

The Apple PCIe host controller is a PCIe host controller with
multiple root ports present in Apple ARM SoC platforms, including
various iPhone and iPad devices and the "Apple Silicon" Macs.

Signed-off-by: Mark Kettenis <redacted>
---
 .../devicetree/bindings/pci/apple,pcie.yaml   | 166 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 167 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/apple,pcie.yaml
diff --git a/Documentation/devicetree/bindings/pci/apple,pcie.yaml b/Documentation/devicetree/bindings/pci/apple,pcie.yaml
new file mode 100644
index 000000000000..bfcbdee79c64
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/apple,pcie.yaml
@@ -0,0 +1,166 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/apple,pcie.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple PCIe host controller
+
+maintainers:
+  - Mark Kettenis <kettenis@openbsd.org>
+
+description: |
+  The Apple PCIe host controller is a PCIe host controller with
+  multiple root ports present in Apple ARM SoC platforms, including
+  various iPhone and iPad devices and the "Apple Silicon" Macs.
+  The controller incorporates Synopsys DesigWare PCIe logic to
+  implements its root ports.  But the ATU found on most DesignWare
+  PCIe host bridges is absent.
blank line
+  All root ports share a single ECAM space, but separate GPIOs are
+  used to take the PCI devices on those ports out of reset.  Therefore
+  the standard "reset-gpio" and "max-link-speed" properties appear on
reset-gpios
+  the child nodes that represent the PCI bridges that correspond to
+  the individual root ports.
blank line
+  MSIs are handled by the PCIe controller and translated into regular
+  interrupts.  A range of 32 MSIs is provided.  These 32 MSIs can be
+  distributed over the root ports as the OS sees fit by programming
+  the PCIe controller's port registers.
+
+allOf:
+  - $ref: /schemas/pci/pci-bus.yaml#
+
+properties:
+  compatible:
+    items:
+      - const: apple,t8103-pcie
+      - const: apple,pcie
+
+  reg:
+    minItems: 3
+    maxItems: 5
+
+  reg-names:
+    minItems: 3
+    maxItems: 5
+    items:
+      - const: config
+      - const: rc
+      - const: port0
+      - const: port1
+      - const: port2
+
+  ranges:
+    minItems: 2
+    maxItems: 2
+
+  interrupts:
+    description:
+      Interrupt specifiers, one for each root port.
+    minItems: 1
+    maxItems: 3
+
+  msi-controller: true
+  msi-parent: true
+
+  msi-ranges:
+    description:
+      A list of pairs <intid span>, where "intid" is the first
+      interrupt number that can be used as an MSI, and "span" the size
+      of that range.
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    items:
+      minItems: 2
+      maxItems: 2
I still have issues I raised on v1 with this property. It's genericish 
looking, but not generic. 'intid' as a single cell can't specify any 
parent interrupt such as a GIC which uses 3 cells. You could put in all 
the cells, but you'd still be assuming which cell you can increment.

I think you should just list all these under 'interrupts' using 
interrupt-names to make your life easier:

interrupt-names:
  items:
    - const: port0
    - const: port1
    - const: port2
    - const: msi0
    - const: msi1
    - const: msi2
    - const: msi3
    ...

Yeah, it's kind of verbose, but if the h/w block handles N interrupts, 
you should list N interrupts. The worst case for the above is N entries 
too if not contiguous.

Rob

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