[v14,19/21] PCI: rcar-gen4-ep: Add R-Car Gen4 PCIe Endpoint support

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 64d4d37bc891..4d877cd18374 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -424,4 +424,13 @@  config PCIE_RCAR_GEN4
 	  Say Y here if you want PCIe host controller support on R-Car Gen4 SoCs.
 	  This uses the DesignWare core.
 
+config PCIE_RCAR_GEN4_EP
+	tristate "Renesas R-Car Gen4 PCIe Endpoint controller"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	depends on PCI_ENDPOINT
+	select PCIE_DW_EP
+	help
+	  Say Y here if you want PCIe endpoint controller support on R-Car Gen4
+	  SoCs. This uses the DesignWare core.
+
 endmenu
diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index 486cf706b53d..0fb0bde26ac4 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -28,6 +28,8 @@  obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
 obj-$(CONFIG_PCIE_VISCONTI_HOST) += pcie-visconti.o
 pcie-rcar-gen4-host-drv-objs := pcie-rcar-gen4.o pcie-rcar-gen4-host.o
 obj-$(CONFIG_PCIE_RCAR_GEN4) += pcie-rcar-gen4-host-drv.o
+pcie-rcar-gen4-ep-drv-objs := pcie-rcar-gen4.o pcie-rcar-gen4-ep.o
+obj-$(CONFIG_PCIE_RCAR_GEN4_EP) += pcie-rcar-gen4-ep-drv.o
 
 # The following drivers are for devices that use the generic ACPI
 # pci_root.c driver but don't support standard ECAM config access.
diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4-ep.c b/drivers/pci/controller/dwc/pcie-rcar-gen4-ep.c
new file mode 100644
index 000000000000..710bbc9e61a5
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4-ep.c
@@ -0,0 +1,166 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PCIe Endpoint driver for Renesas R-Car Gen4 Series SoCs
+ * Copyright (C) 2022-2023 Renesas Electronics Corporation
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+
+#include "pcie-rcar-gen4.h"
+#include "pcie-designware.h"
+
+static void rcar_gen4_pcie_ep_pre_init(struct dw_pcie_ep *ep)
+{
+	struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+	u8 val;
+
+	rcar_gen4_pcie_set_device_type(rcar, false, dw->num_lanes);
+
+	dw_pcie_dbi_ro_wr_en(dw);
+
+	/* Single function */
+	val = dw_pcie_readb_dbi(dw, PCI_HEADER_TYPE);
+	val &= ~PCI_HEADER_TYPE_MULTI_FUNC;
+	dw_pcie_writeb_dbi(dw, PCI_HEADER_TYPE, val);
+
+	dw_pcie_dbi_ro_wr_dis(dw);
+
+	writel(PCIEDMAINTSTSEN_INIT, rcar->base + PCIEDMAINTSTSEN);
+}
+
+static void rcar_gen4_pcie_ep_deinit(struct dw_pcie_ep *ep)
+{
+	struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
+	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
+
+	writel(0, rcar->base + PCIEDMAINTSTSEN);
+}
+
+static int rcar_gen4_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
+				       enum pci_epc_irq_type type,
+				       u16 interrupt_num)
+{
+	struct dw_pcie *dw = to_dw_pcie_from_ep(ep);
+
+	switch (type) {
+	case PCI_EPC_IRQ_INTX:
+		return dw_pcie_ep_raise_intx_irq(ep, func_no);
+	case PCI_EPC_IRQ_MSI:
+		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
+	default:
+		dev_err(dw->dev, "Unknown IRQ type\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct pci_epc_features rcar_gen4_pcie_epc_features = {
+	.linkup_notifier = false,
+	.msi_capable = true,
+	.msix_capable = false,
+	.reserved_bar = 1 << BAR_5,
+	.align = SZ_1M,
+};
+
+static const struct pci_epc_features*
+rcar_gen4_pcie_ep_get_features(struct dw_pcie_ep *ep)
+{
+	return &rcar_gen4_pcie_epc_features;
+}
+
+static const struct dw_pcie_ep_ops pcie_ep_ops = {
+	.ep_pre_init = rcar_gen4_pcie_ep_pre_init,
+	.ep_deinit = rcar_gen4_pcie_ep_deinit,
+	.raise_irq = rcar_gen4_pcie_ep_raise_irq,
+	.get_features = rcar_gen4_pcie_ep_get_features,
+};
+
+static int rcar_gen4_add_pcie_ep(struct rcar_gen4_pcie *rcar,
+				 struct platform_device *pdev)
+{
+	struct dw_pcie_ep *ep = &rcar->dw.ep;
+	int ret;
+
+	ep->ops = &pcie_ep_ops;
+
+	ret = dw_pcie_ep_init(ep);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to initialize endpoint\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void rcar_gen4_remove_pcie_ep(struct rcar_gen4_pcie *rcar)
+{
+	dw_pcie_ep_exit(&rcar->dw.ep);
+}
+
+static int rcar_gen4_pcie_ep_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rcar_gen4_pcie *rcar;
+	int err;
+
+	rcar = rcar_gen4_pcie_devm_alloc(dev);
+	if (!rcar)
+		return -ENOMEM;
+
+	err = rcar_gen4_pcie_get_resources(rcar, pdev);
+	if (err < 0) {
+		dev_err(dev, "Failed to request resource: %d\n", err);
+		return err;
+	}
+
+	platform_set_drvdata(pdev, rcar);
+
+	err = rcar_gen4_pcie_prepare(rcar);
+	if (err < 0)
+		return err;
+
+	err = rcar_gen4_add_pcie_ep(rcar, pdev);
+	if (err < 0)
+		goto err_add;
+
+	return 0;
+
+err_add:
+	rcar_gen4_pcie_unprepare(rcar);
+
+	return err;
+}
+
+static int rcar_gen4_pcie_ep_remove(struct platform_device *pdev)
+{
+	struct rcar_gen4_pcie *rcar = platform_get_drvdata(pdev);
+
+	rcar_gen4_remove_pcie_ep(rcar);
+	rcar_gen4_pcie_unprepare(rcar);
+
+	return 0;
+}
+
+static const struct of_device_id rcar_gen4_pcie_of_match[] = {
+	{ .compatible = "renesas,rcar-gen4-pcie-ep", },
+	{},
+};
+
+static struct platform_driver rcar_gen4_pcie_ep_driver = {
+	.driver = {
+		.name = "pcie-rcar-gen4-ep",
+		.of_match_table = rcar_gen4_pcie_of_match,
+	},
+	.probe = rcar_gen4_pcie_ep_probe,
+	.remove = rcar_gen4_pcie_ep_remove,
+};
+module_platform_driver(rcar_gen4_pcie_ep_driver);
+
+MODULE_DESCRIPTION("Renesas R-Car Gen4 PCIe endpoint controller driver");
+MODULE_LICENSE("GPL");