PCI: keembay: Add support for Intel Keem Bay

Add driver for Intel Keem Bay SoC PCIe controller. This controller
is based on DesignWare PCIe core.

In Root Complex mode, only internal reference clock is possible for
Keem Bay A0. For Keem Bay B0, external reference clock can be used
and will be the default configuration. Currently, keembay_pcie_of_data
structure has one member. It will be expanded later to handle this
difference.

Endpoint mode link initialization is handled by the boot firmware.

Link: https://lore.kernel.org/r/20210805211010.29484-3-srikanth.thokala@intel.comSigned-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

MAINTAINERS

@@ -14422,6 +14422,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/pci/hisilicon-histb-pcie.txt
 F:	drivers/pci/controller/dwc/pcie-histb.c
 
+PCIE DRIVER FOR INTEL KEEM BAY
+M:	Srikanth Thokala <srikanth.thokala@intel.com>
+L:	linux-pci@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/pci/intel,keembay-pcie*
+F:	drivers/pci/controller/dwc/pcie-keembay.c
+
 PCIE DRIVER FOR MEDIATEK
 M:	Ryder Lee <ryder.lee@mediatek.com>
 M:	Jianjun Wang <jianjun.wang@mediatek.com>

drivers/pci/controller/dwc/Kconfig

@@ -225,6 +225,34 @@ config PCIE_INTEL_GW
 	  The PCIe controller uses the DesignWare core plus Intel-specific
 	  hardware wrappers.
 
+config PCIE_KEEMBAY
+	bool
+
+config PCIE_KEEMBAY_HOST
+	bool "Intel Keem Bay PCIe controller - Host mode"
+	depends on ARCH_KEEMBAY || COMPILE_TEST
+	depends on PCI && PCI_MSI_IRQ_DOMAIN
+	select PCIE_DW_HOST
+	select PCIE_KEEMBAY
+	help
+	  Say 'Y' here to enable support for the PCIe controller in Keem Bay
+	  to work in host mode.
+	  The PCIe controller is based on DesignWare Hardware and uses
+	  DesignWare core functions.
+
+config PCIE_KEEMBAY_EP
+	bool "Intel Keem Bay PCIe controller - Endpoint mode"
+	depends on ARCH_KEEMBAY || COMPILE_TEST
+	depends on PCI && PCI_MSI_IRQ_DOMAIN
+	depends on PCI_ENDPOINT
+	select PCIE_DW_EP
+	select PCIE_KEEMBAY
+	help
+	  Say 'Y' here to enable support for the PCIe controller in Keem Bay
+	  to work in endpoint mode.
+	  The PCIe controller is based on DesignWare Hardware and uses
+	  DesignWare core functions.
+
 config PCIE_KIRIN
 	depends on OF && (ARM64 || COMPILE_TEST)
 	bool "HiSilicon Kirin series SoCs PCIe controllers"

drivers/pci/controller/dwc/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
 obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
 obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
 obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
+obj-$(CONFIG_PCIE_KEEMBAY) += pcie-keembay.o
 obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
 obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
 obj-$(CONFIG_PCI_MESON) += pci-meson.o