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

Message

Mark Kettenis May 30, 2021, 10:43 p.m. UTC

From: Mark Kettenis <[e-mail]>

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.


Changelog:

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
      "iommu-map-mask"
    - 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 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 arch/arm64/boot/dts/apple/t8103.dtsi          |  63 +++++++
 3 files changed, 231 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/apple,pcie.yaml