This patch adds support for rcar PCIe controller to work in endpoint mode.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/pci/controller/Kconfig        |   7 +
 drivers/pci/controller/Makefile       |   1 +
 drivers/pci/controller/pcie-rcar-ep.c | 497 ++++++++++++++++++++++++++
 drivers/pci/controller/pcie-rcar.h    |   6 +
 4 files changed, 511 insertions(+)
 create mode 100644 drivers/pci/controller/pcie-rcar-ep.c

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index b022ac5678f7..69b1c778dad4 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig

@@ -61,6 +61,13 @@ config PCIE_RCAR_HOST
 	help
 	  Say Y here if you want PCIe controller support on R-Car SoCs in host mode.
 
+config PCIE_RCAR_EP
+	bool "Renesas R-Car PCIe endpoint controller"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	depends on PCI_ENDPOINT
+	help
+	  Say Y here if you want PCIe controller support on R-Car SoCs in endpoint mode.
+
 config PCI_HOST_COMMON
 	bool
 	select PCI_ECAM

diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
index 69ba1dbf837b..61505b1fc66a 100644
--- a/drivers/pci/controller/Makefile
+++ b/drivers/pci/controller/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_PCI_AARDVARK) += pci-aardvark.o
 obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
 obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
 obj-$(CONFIG_PCIE_RCAR_HOST) += pcie-rcar.o pcie-rcar-host.o
+obj-$(CONFIG_PCIE_RCAR_EP) += pcie-rcar.o pcie-rcar-ep.o
 obj-$(CONFIG_PCI_HOST_COMMON) += pci-host-common.o
 obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
 obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o

diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
new file mode 100644
index 000000000000..40cd2aad8c3c
--- /dev/null
+++ b/drivers/pci/controller/pcie-rcar-ep.c

@@ -0,0 +1,497 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe endpoint driver for Renesas R-Car SoCs
+ *  Copyright (c) 2020 Renesas Electronics Europe GmbH
+ *
+ * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/pci-epc.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+#include "pcie-rcar.h"
+
+#define MAX_NR_INBOUND_MAPS	6
+#define MAX_NR_OUTBOUND_MAPS	4
+
+/* Structure representing the PCIe interface */
+struct rcar_pcie {
+	phys_addr_t		*ob_addr;
+	struct pci_epc_mem_window *ob_window;
+	struct pci_epc		*epc;
+	struct device		*dev;
+	void __iomem		*base;
+	u8			max_functions;
+	unsigned int		bar_to_atu[MAX_NR_INBOUND_MAPS];
+	unsigned long		*ib_window_map;
+	u32			num_ib_windows;
+	u32			num_ob_windows;
+};
+
+static void rcar_pcie_ep_hw_init(struct rcar_pcie *pcie)
+{
+	u32 val;
+
+	rcar_pci_write_reg(pcie->base, 0, PCIETCTLR);
+
+	/* Set endpoint mode */
+	rcar_pci_write_reg(pcie->base, 0, PCIEMSR);
+
+	/* Initialize default capabilities. */
+	rcar_rmw32(pcie->base, REXPCAP(0), 0xff, PCI_CAP_ID_EXP);
+	rcar_rmw32(pcie->base, REXPCAP(PCI_EXP_FLAGS),
+		   PCI_EXP_FLAGS_TYPE, PCI_EXP_TYPE_ENDPOINT << 4);
+	rcar_rmw32(pcie->base, RCONF(PCI_HEADER_TYPE), 0x7f,
+		   PCI_HEADER_TYPE_NORMAL);
+
+	/* Write out the physical slot number = 0 */
+	rcar_rmw32(pcie->base, REXPCAP(PCI_EXP_SLTCAP), PCI_EXP_SLTCAP_PSN, 0);
+
+	val = rcar_pci_read_reg(pcie->base, EXPCAP(1));
+	/* device supports fixed 128 bytes MPSS */
+	val &= ~GENMASK(2, 0);
+	/* L1 to L0 transition latency no time limit */
+	val |= GENMASK(11, 9);
+	/* L0s to L0 transistion no time limit */
+	val |= GENMASK(8, 6);
+	rcar_pci_write_reg(pcie->base, val, EXPCAP(1));
+
+	val = rcar_pci_read_reg(pcie->base, EXPCAP(2));
+	/* read requests size 128 bytes */
+	val &= ~GENMASK(14, 12);
+	/* payload size 128 bytes */
+	val &= ~GENMASK(7, 5);
+	/* disable relaxed ordering transaction */
+	val &= ~BIT(4);
+	rcar_pci_write_reg(pcie->base, val, EXPCAP(2));
+
+	val = rcar_pci_read_reg(pcie->base, EXPCAP(4));
+	/* disable ASPM control */
+	val &= ~GENMASK(1, 0);
+	rcar_pci_write_reg(pcie->base, val, EXPCAP(4));
+
+	/* Set target link speed to 5.0 GT/s */
+	rcar_rmw32(pcie->base, EXPCAP(12), PCI_EXP_LNKSTA_CLS,
+		   PCI_EXP_LNKSTA_CLS_5_0GB);
+
+	/* Set the completion timer timeout to the maximum 50ms. */
+	rcar_rmw32(pcie->base, TLCTLR + 1, 0x3f, 50);
+
+	/* Terminate list of capabilities (Next Capability Offset=0) */
+	rcar_rmw32(pcie->base, RVCCAP(0), 0xfff00000, 0);
+
+	/* flush modifications */
+	wmb();
+}
+
+static int rcar_pcie_parse_outbound_ranges(struct rcar_pcie *pcie,
+					   struct platform_device *pdev)
+{
+	char outbound_name[10];
+	struct resource *res;
+	unsigned int i = 0;
+
+	pcie->num_ob_windows = 0;
+	for (i = 0; i < MAX_NR_OUTBOUND_MAPS; i++) {
+		sprintf(outbound_name, "memory%u", i);
+		res = platform_get_resource_byname(pdev,
+						   IORESOURCE_MEM,
+						   outbound_name);
+		if (!res) {
+			dev_err(pcie->dev, "missing outbound window %u\n", i);
+			return -EINVAL;
+		}
+		if (!devm_request_mem_region(&pdev->dev, res->start,
+					     resource_size(res),
+					     outbound_name)) {
+			dev_err(pcie->dev, "Cannot request memory region %s.\n",
+				outbound_name);
+			return -EIO;
+		}
+
+		pcie->ob_window[i].phys_base = res->start;
+		pcie->ob_window[i].size = resource_size(res);
+		/* controller doesn't support multiple allocation
+		 * from same window, so set page_size to window size
+		 */
+		pcie->ob_window[i].page_size = resource_size(res);