[PATCH 0/3] Add PCIe DT support for TI's J784S4 SoC

[Siddharth Vadapalli]

Hello,

TI's J784S4 SoC has two Gen3 x4 Lane PCIe Controllers. This series adds
the necessary device-tree support to enable both PCIe instances in Root
Complex mode of operation by default. The device-tree overlay to enable
both instances in Endpoint mode of operation is also present in this
series.

**NOTE**
This series depends on:
1. https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240124122936.816142-1-s-vadapalli@ti.com/
   for adding the Device ID in the bindings for J784S4 SoC.

2. https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240129104958.1139787-1-s-vadapalli@ti.com/
   for enabling support for configuring the PCIe mode of operation,
   number of lanes and link speed when the System Controller node
   in the device-tree is modelled as a "simple-bus" which happens to
   be the case for J784S4 SoC:
   https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/ti/k3-j784s4-main.dtsi#L45

3. https://patchwork.kernel.org/project/linux-arm-kernel/patch/20240125100501.4137977-2-c-vankar@ti.com/
   for fixing the "serdes_ln_ctrl" node in order to ensure that the PCIe
   lanes are mapped correctly to the corresponding Serdes Lanes.

This series has been tested on top of linux-next tagged next-20240129
after applying the above dependent patches and enabling the relevant
PCIe driver configs.

Test Logs:
1. PCIe0 and PCIe1 in Root Complex Modes of operation with an NVMe SSD
connected to PCIe0 instance and Read performance measured using hdparm:
https://gist.github.com/Siddharth-Vadapalli-at-TI/6592af75ee8ba3f3bdd372a882de8b43
2. PCIe0 in Endpoint Mode on one J784S4-EVM with PCIe0 in RC Mode on
other J784S4-EVM connected to each other. Enumeration of PCIe0 as an
Endpoint is verified on the J784S4-EVM where PCIe0 is in RC Mode:
https://gist.github.com/Siddharth-Vadapalli-at-TI/cef85519669c12894352ce081ea2a8ab
3. PCIe1 in Endpoint Mode on one J784S4-EVM with PCIe1 in RC Mode on
other J784S4-EVM connected to each other. Enumeration of PCIe1 as an
Endpoint is verified on the J784S4-EVM where PCIe1 is in RC Mode:
https://gist.github.com/Siddharth-Vadapalli-at-TI/646d51757cffd651b51bac33d138a8ac

Regards,
Siddharth.

Siddharth Vadapalli (3):
  arm64: dts: ti: k3-j784s4-main: Add PCIe nodes
  arm64: dts: ti: k3-j784s4-evm: Enable PCIe0 and PCIe1 in RC Mode
  arm64: dts: ti: k3-j784s4-evm: Add overlay for PCIE0 and PCIE1 EP Mode

 arch/arm64/boot/dts/ti/Makefile               |  7 +-
 .../dts/ti/k3-j784s4-evm-pcie0-pcie1-ep.dtso  | 79 +++++++++++++++++
 arch/arm64/boot/dts/ti/k3-j784s4-evm.dts      | 46 ++++++++++
 arch/arm64/boot/dts/ti/k3-j784s4-main.dtsi    | 84 +++++++++++++++++++
 4 files changed, 215 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/boot/dts/ti/k3-j784s4-evm-pcie0-pcie1-ep.dtso

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2.34.1