[PATCH v2 0/2] Apple M1 PCIe DT bindings

From: Mark Kettenis
Date: Sun May 30 2021 - 18:44:32 EST

From: Mark Kettenis <kettenis@xxxxxxxxxxx>

This small series adds bindings for the PCIe controller found on the
Apple M1 SoC.

At this point, the primary consumer for these bindings is U-Boot.
With these bindings U-Boot can bring up the links for the root ports
of the PCIe root complex. A simple OS driver can then provide
standard ECAM access and manage MSI interrupts to provide access
to the built-in Ethernet and XHCI controllers of the Mac mini.

The Apple controller incorporates Synopsys Designware PCIe logic
to implement its root port. But unlike other hardware currently
supported by U-Boot and the Linux kernel the Apple hardware
integrates multiple root ports. As such the existing bindings
for the DWC PCIe interface can't be used. There is a single ECAM
space for all root space, but separate GPIOs to take the PCI devices
on those ports out of reset. Therefore the standard "reset-gpio" and
"max-link-speed" properties appear on the child nodes representing
the PCI devices that correspond to the individual root ports.

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 port registers.

I still hope to hear from Marc Zyngier on the way MSIs are represented
in this binding.

Patch 2/2 of this series depends on the pinctrl series I sent earlier.


v2: - Adjust name for ECAM in "reg-names"
- Drop "phy" registers
- Expand description
- Add description for "interrupts"
- Fix incorrect minItems for "interrupts"
- Fix incorrect MaxItems for "reg-names"
- Document the use of "msi-controller", "msi-parent", "iommu-map" and
- Fix "bus-range" and "iommu-map" properties in the example

Mark Kettenis (2):
dt-bindings: pci: Add DT bindings for apple,pcie
arm64: apple: Add PCIe node

.../devicetree/bindings/pci/apple,pcie.yaml | 167 ++++++++++++++++++
arch/arm64/boot/dts/apple/t8103.dtsi | 63 +++++++
3 files changed, 231 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pci/apple,pcie.yaml