PCI: s32g: Add support for PCIe controller

The S32G SoC family has 2 PCIe controllers based on Designware IP.

Add the support for Host mode.

Change since v5:

- Removed relocatable bit in yaml
- Dropped pcie-nxp-s32g-regs.h and moved reg definition in pcie-nxp-s32g.c
- Removed a useless ret
- Change kconfig from tri to bool because of memblock_start_of_DRAM()

Change since v4:

- Moved allof position and added interrupt-names' restriction in yaml file
- Removed PCIE_S32G_PE0_LINK_DBG_2 and instead use PCIE_PORT_DEBUG0|1
  after receiving confirmation that they are the same.

Change since v3:

- Added Root Port node and reorder irq in binding
- Added Root Port management in driver 
- Fix Kconfig PCIE_NXP_S32G position
- Use default pme_turn_off method
- Use ops->init() to simplify init and suspend/resume sequence
- Fix some typos.
- Removed MPS and ERROR config. Let core code configs them.
- Removed s32g_pcie_disable_equalization() from internal team request
- Removed dw_pcie_link_up() from suspend/resume functions with [1]

- I'm still waiting feedback from internal team before removing
.get_ltssm() and .link_up() functions.

[1] https://lore.kernel.org/all/20251107044319.8356-1-manivan...

Change since v2:

- More cleanup on DT binding to comply with schemas/pci/snps,dw-pcie.yaml
- Added new reg and bit fields in pcie-designware.h 
- Rename Kconfig PCIE_NXP_S32G and files to use pcie-nxp-s32g prefix
- Prefixed s32G registers with PCIE_S32G_ and use generic regs otherwise
- Use memblock_start_of_DRAM to set coherency boundary and add comments
- Fixed suspend/resume sequence by adding missing pme_turn_off function
- Added .probe_type = PROBE_PREFER_ASYNCHRONOUS to speedup probe
- Added pm_runtime_no_callbacks() as device doesn't have runtime ops
- Use writel/readl in ctrl function instead of dw_pcie_write/read
- Move Maintainer section in a dedicated entry

Change since v1:

- Cleanup DT binding
  - Removed useless description and fixed typo, naming and indentation.
  - Removed nxp,phy-mode binding until we agreed on a generic binding.
    Default (crnss) mode is used for now. Generic binding wil be discussed
    in a separate patch.
  - Removed max-link-speed and num-lanes which are coming from
    snps,dw-pcie-common.yaml. They are needed only if to restrict from the
    the default hw config.
  - Added unevaluatedProperties: false
  - Keep Phys in host node until dw support Root Port node.

- Removed nxp-s32g-pcie-phy-submode.h until there is a generic clock and
  spectrum binding.

- Rename files to start with pcie-s32g instead of pci-s32g

- Cleanup pcie-s32-reg.h and use dw_pcie_find_capability()

- cleanup and rename in s32g-pcie.c in addtion to remove useless check or
  duplicate code.

- dw_pcie_suspend/resume_noirq() doesn't woork, need to set child device
  to reach lowest state.

- Added L: imx@lists.linux.dev in MAINTAINERS


Vincent Guittot (4):
  dt-bindings: PCI: s32g: Add NXP PCIe controller
  PCI: dw: Add more registers and bitfield definition
  PCI: s32g: Add initial PCIe support (RC)
  MAINTAINERS: Add MAINTAINER for NXP S32G PCIe driver

 .../bindings/pci/nxp,s32g-pcie.yaml           | 130 ++++++
 MAINTAINERS                                   |   9 +
 drivers/pci/controller/dwc/Kconfig            |  10 +
 drivers/pci/controller/dwc/Makefile           |   1 +
 drivers/pci/controller/dwc/pcie-designware.h  |   8 +
 drivers/pci/controller/dwc/pcie-nxp-s32g.c    | 404 ++++++++++++++++++
 6 files changed, 562 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/nxp,s32g-pcie.yaml
 create mode 100644 drivers/pci/controller/dwc/pcie-nxp-s32g.c

-- 
2.43.0