PCI: cadence: Add EndPoint Controller driver for Cadence PCIe controller

This patch adds support to the Cadence PCIe controller in endpoint mode.

Since pieces of source code are shared with the host driver (Root
Complex mode), we create a new directory under drivers/pci dedicated to
the Cadence PCIe controller. The common code is placed into
drivers/pci/cadence/pcie-cadence.c and used by both the host and
endpoint controller drivers.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

MAINTAINERS

@@ -10407,7 +10407,7 @@ M:	Alan Douglas <adouglas@cadence.com>
 L:	linux-pci@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/pci/cdns,*.txt
-F:	drivers/pci/host/pcie-cadence*
+F:	drivers/pci/cadence/pcie-cadence*
 
 PCI DRIVER FOR FREESCALE LAYERSCAPE
 M:	Minghuan Lian <minghuan.Lian@freescale.com>

drivers/pci/Kconfig

@@ -136,6 +136,7 @@ config PCI_HYPERV
           PCI devices from a PCI backend to support PCI driver domains.
 
 source "drivers/pci/hotplug/Kconfig"
+source "drivers/pci/cadence/Kconfig"
 source "drivers/pci/dwc/Kconfig"
 source "drivers/pci/host/Kconfig"
 source "drivers/pci/endpoint/Kconfig"

drivers/pci/Makefile

@@ -56,5 +56,6 @@ obj-y += switch/
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
 
 # Endpoint library must be initialized before its users
+obj-$(CONFIG_PCIE_CADENCE)	+= cadence/
 # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
 obj-y				+= dwc/

drivers/pci/cadence/Kconfig

@@ -0,0 +1,27 @@
+menu "Cadence PCIe controllers support"
+
+config PCIE_CADENCE
+	bool
+
+config PCIE_CADENCE_HOST
+	bool "Cadence PCIe host controller"
+	depends on OF
+	depends on PCI
+	select IRQ_DOMAIN
+	select PCIE_CADENCE
+	help
+	  Say Y here if you want to support the Cadence PCIe controller in host
+	  mode. This PCIe controller may be embedded into many different vendors
+	  SoCs.
+
+config PCIE_CADENCE_EP
+	bool "Cadence PCIe endpoint controller"
+	depends on OF
+	depends on PCI_ENDPOINT
+	select PCIE_CADENCE
+	help
+	  Say Y here if you want to support the Cadence PCIe  controller in
+	  endpoint mode. This PCIe controller may be embedded into many
+	  different vendors SoCs.
+
+endmenu

drivers/pci/cadence/Makefile

@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
+obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
+obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep.o