[FFe] PolarFire Icicle Kit: enable PCIe support

[Heinrich Schuchardt]

The PolarFire Icicle Kit provides a PCIe slot. With our 5.19 kernel it is not usable. Please, add the following patches:

# https://lore<email address hidden>/
riscv: dts: microchip: add pci dma ranges for the icicle
# https://lore<email address hidden>/
riscv: dts: microchip: move the mpfs' pci node to
# https://lore<email address hidden>/
riscv: dts: microchip: icicle: update pci address
# https://lore<email address hidden>/
riscv: dts: microchip: icicle: re-jig fabric peripheral
# https://lore<email address hidden>/
riscv: dts: microchip: add fabric address translation
# https://lore<email address hidden>/
PCI: microchip: add fabric address translation properties

All patches are strictly restricted to the PolarFire Icicle Kit and have no impact on any other RISC-V boards that we support.

Best regards

Heinrich

[Heinrich Schuchardt (xypron)]

With Kinetic we are trying to bring support for the PolarFire Icicle Kit which was missing in Jammy.
Without PCI this support would be incomplete.

The patches don't touch any code relevant for other boards. As the board has not been previously supported there is not risk of regression.

Please, grant a feature freeze exception to add the missing functionality in the kernel.

[Graham Inggs (ginggs)]

This is fine from Release Team's perspective, so FFe granted, but still needs Kernel Team to incorporate the changes.

[Heinrich Schuchardt (xypron)]

Microchip informed us that a matching and tested set of upstream Linux PCIe patches matching the updcoming HSS v2022.10 is not available. We should postpone adding patches for PCIe to after the 2022.10 Ubuntu release.

[Heinrich Schuchardt (xypron)]

The attached patch can be used to disable PCIe in the device-tree:

[PATCH] riscv: dts: microchip: disable the icicle's pcie controller

PCIe on the icicle kit is unfortunately non-functional in the v2022.10
design as things stand. Disable it in the devicetree so that there will
be no issues if the driver happens to be enabled.

Signed-off-by: Conor Dooley <email address hidden>

[Heinrich Schuchardt (xypron)]

Closing this as the linked patches are outdated. Upstream work for PCIe on the Icicle kit is still ongoing.

[Isaac True (itrue)]

@xypron is the work still ongoing upstream? Could we maybe re-open this bug as PCIe is still not supported?

[Heinrich Schuchardt (xypron)]

@itrue
The issue is described on https://wiki.ubuntu.com/RISC-V/PolarFire%20SoC%20FPGA%20Icicle%20Kit.

Upstream kernel patches are still under discussion. Reopening the issue does not help unless there are upstream patches that we can merge into our kernel.

Here is the latest work on cleaning up the code:

[PATCH v9 0/22] Refactoring Microchip PCIe driver and add StarFive PCIe
https://<email address hidden>/

[Isaac True (itrue)]

Thanks @xypron

Re-opened the bug so that we have somewhere to track the progress, even if we can't merge anything right now.