PCI: amd-mdb: Add AMD MDB Root Port driver

Add support for AMD MDB (Multimedia DMA Bridge) IP core as Root Port.

The Versal2 devices include MDB Module. The integrated block for MDB
along with the integrated bridge can function as PCIe Root Port
controller at Gen5 32-GT/s operation per lane.

Bridge supports error and INTx interrupts and are handled using platform
specific interrupt line in Versal2.

Signed-off-by: Thippeswamy Havalige <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[bhelgaas: only present on ARM64-based SoCs; squash Kconfig dependency on
ARM64 from Geert Uytterhoeven <[email protected]>:
https://lore.kernel.org/r/eaef1dea7edcf146aa377d5e5c5c85a76ff56bae.1742306383.git.geert+renesas@glider.be]
Signed-off-by: Bjorn Helgaas <[email protected]>
[kwilczynski: commit log, code comments and error messages clean-up,
drop redundant "depends on PCI" from Kconfig, expose the error code
as part of error messages where appropriatie, change "depends on"
expression to match existing style from other drivers]
Signed-off-by: Krzysztof Wilczyński <[email protected]>

Author: Thippeswamy Havalige

drivers/pci/controller/dwc/Kconfig

@@ -27,6 +27,17 @@ config PCIE_AL
 	  required only for DT-based platforms. ACPI platforms with the
 	  Annapurna Labs PCIe controller don't need to enable this.
 
+config PCIE_AMD_MDB
+	bool "AMD MDB Versal2 PCIe controller"
+	depends on OF && (ARM64 || COMPILE_TEST)
+	depends on PCI_MSI
+	select PCIE_DW_HOST
+	help
+	  Say Y here if you want to enable PCIe controller support on AMD
+	  Versal2 SoCs. The AMD MDB Versal2 PCIe controller is based on
+	  DesignWare IP and therefore the driver re-uses the DesignWare
+	  core functions to implement the driver.
+
 config PCI_MESON
 	tristate "Amlogic Meson PCIe controller"
 	default m if ARCH_MESON

drivers/pci/controller/dwc/Makefile

@@ -3,6 +3,7 @@ obj-$(CONFIG_PCIE_DW) += pcie-designware.o
 obj-$(CONFIG_PCIE_DW_HOST) += pcie-designware-host.o
 obj-$(CONFIG_PCIE_DW_EP) += pcie-designware-ep.o
 obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o
+obj-$(CONFIG_PCIE_AMD_MDB) += pcie-amd-mdb.o
 obj-$(CONFIG_PCIE_BT1) += pcie-bt1.o
 obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
 obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o