PCI: xgene: Add APM X-Gene PCIe driver

Add the AppliedMicro X-Gene SOC PCIe host controller driver.  The X-Gene
PCIe controller supports up to 8 lanes and GEN3 speed.  The X-Gene SOC
supports up to 5 PCIe ports.

[bhelgaas: folded in MAINTAINERS and bindings updates]
Tested-by: Ming Lei <ming.lei@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Signed-off-by: Tanmay Inamdar <tinamdar@apm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Liviu Dudau <Liviu.Dudau@arm.com> (driver)

5 files changed, 735 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pci/xgene-pci.txt b/Documentation/devicetree/bindings/pci/xgene-pci.txt
new file mode 100644
index 000000000000..1070b068c7c6
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/xgene-pci.txt
@@ -0,0 +1,57 @@
+* AppliedMicro X-Gene PCIe interface
+
+Required properties:
+- device_type: set to "pci"
+- compatible: should contain "apm,xgene-pcie" to identify the core.
+- reg: A list of physical base address and length for each set of controller
+       registers. Must contain an entry for each entry in the reg-names
+       property.
+- reg-names: Must include the following entries:
+  "csr": controller configuration registers.
+  "cfg": pcie configuration space registers.
+- #address-cells: set to <3>
+- #size-cells: set to <2>
+- ranges: ranges for the outbound memory, I/O regions.
+- dma-ranges: ranges for the inbound memory regions.
+- #interrupt-cells: set to <1>
+- interrupt-map-mask and interrupt-map: standard PCI properties
+	to define the mapping of the PCIe interface to interrupt
+	numbers.
+- clocks: from common clock binding: handle to pci clock.
+
+Optional properties:
+- status: Either "ok" or "disabled".
+- dma-coherent: Present if dma operations are coherent
+
+Example:
+
+SoC specific DT Entry:
+
+	pcie0: pcie@1f2b0000 {
+		status = "disabled";
+		device_type = "pci";
+		compatible = "apm,xgene-storm-pcie", "apm,xgene-pcie";
+		#interrupt-cells = <1>;
+		#size-cells = <2>;
+		#address-cells = <3>;
+		reg = < 0x00 0x1f2b0000 0x0 0x00010000   /* Controller registers */
+			0xe0 0xd0000000 0x0 0x00040000>; /* PCI config space */
+		reg-names = "csr", "cfg";
+		ranges = <0x01000000 0x00 0x00000000 0xe0 0x10000000 0x00 0x00010000   /* io */
+			  0x02000000 0x00 0x80000000 0xe1 0x80000000 0x00 0x80000000>; /* mem */
+		dma-ranges = <0x42000000 0x80 0x00000000 0x80 0x00000000 0x00 0x80000000
+			      0x42000000 0x00 0x00000000 0x00 0x00000000 0x80 0x00000000>;
+		interrupt-map-mask = <0x0 0x0 0x0 0x7>;
+		interrupt-map = <0x0 0x0 0x0 0x1 &gic 0x0 0xc2 0x1
+				 0x0 0x0 0x0 0x2 &gic 0x0 0xc3 0x1
+				 0x0 0x0 0x0 0x3 &gic 0x0 0xc4 0x1
+				 0x0 0x0 0x0 0x4 &gic 0x0 0xc5 0x1>;
+		dma-coherent;
+		clocks = <&pcie0clk 0>;
+	};
+
+
+Board specific DT Entry:
+	&pcie0 {
+		status = "ok";
+	};
diff --git a/MAINTAINERS b/MAINTAINERS
index 1ff06dee651d..076eb68874f4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6868,6 +6868,14 @@ F:	include/linux/pci*
 F:	arch/x86/pci/
 F:	arch/x86/kernel/quirks.c
 
+PCI DRIVER FOR APPLIEDMICRO XGENE
+M:	Tanmay Inamdar <tinamdar@apm.com>
+L:	linux-pci@vger.kernel.org
+L:	linux-arm-kernel@lists.infradead.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/pci/xgene-pci.txt
+F:	drivers/pci/host/pci-xgene.c
+
 PCI DRIVER FOR IMX6
 M:	Richard Zhu <r65037@freescale.com>
 M:	Shawn Guo <shawn.guo@freescale.com>
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 8922c376456a..d55de1b6ddde 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -63,4 +63,14 @@ config PCIE_SPEAR13XX
 	help
 	  Say Y here if you want PCIe support on SPEAr13XX SoCs.
 
+config PCI_XGENE
+	bool "X-Gene PCIe controller"
+	depends on ARCH_XGENE
+	depends on OF
+	select PCIEPORTBUS
+	help
+	  Say Y here if you want internal PCI support on APM X-Gene SoC.
+	  There are 5 internal PCIe ports available. Each port is GEN3 capable
+	  and have varied lanes from x1 to x8.
+
 endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index d0e88f114ff9..845611ff3de9 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
 obj-$(CONFIG_PCI_RCAR_GEN2_PCIE) += pcie-rcar.o
 obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
 obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
+obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
new file mode 100644
index 000000000000..9ecabfa8c634
--- /dev/null
+++ b/drivers/pci/host/pci-xgene.c
@@ -0,0 +1,659 @@
+/**
+ * APM X-Gene PCIe Driver
+ *
+ * Copyright (c) 2014 Applied Micro Circuits Corporation.
+ *
+ * Author: Tanmay Inamdar <tinamdar@apm.com>.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/clk-private.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/memblock.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define PCIECORE_CTLANDSTATUS		0x50
+#define PIM1_1L				0x80
+#define IBAR2				0x98
+#define IR2MSK				0x9c
+#define PIM2_1L				0xa0
+#define IBAR3L				0xb4
+#define IR3MSKL				0xbc
+#define PIM3_1L				0xc4
+#define OMR1BARL			0x100
+#define OMR2BARL			0x118
+#define OMR3BARL			0x130
+#define CFGBARL				0x154
+#define CFGBARH				0x158
+#define CFGCTL				0x15c
+#define RTDID				0x160
+#define BRIDGE_CFG_0			0x2000
+#define BRIDGE_CFG_4			0x2010
+#define BRIDGE_STATUS_0			0x2600
+
+#define LINK_UP_MASK			0x00000100
+#define AXI_EP_CFG_ACCESS		0x10000
+#define EN_COHERENCY			0xF0000000
+#define EN_REG				0x00000001
+#define OB_LO_IO			0x00000002
+#define XGENE_PCIE_VENDORID		0x10E8
+#define XGENE_PCIE_DEVICEID		0xE004
+#define SZ_1T				(SZ_1G*1024ULL)
+#define PIPE_PHY_RATE_RD(src)		((0xc000 & (u32)(src)) >> 0xe)
+
+struct xgene_pcie_port {
+	struct device_node	*node;
+	struct device		*dev;
+	struct clk		*clk;
+	void __iomem		*csr_base;
+	void __iomem		*cfg_base;
+	unsigned long		cfg_addr;
+	bool			link_up;
+};
+
+static inline u32 pcie_bar_low_val(u32 addr, u32 flags)
+{
+	return (addr & PCI_BASE_ADDRESS_MEM_MASK) | flags;
+}
+
+/* PCIe Configuration Out/In */
+static inline void xgene_pcie_cfg_out32(void __iomem *addr, int offset, u32 val)
+{
+	writel(val, addr + offset);
+}
+
+static inline void xgene_pcie_cfg_out16(void __iomem *addr, int offset, u16 val)
+{
+	u32 val32 = readl(addr + (offset & ~0x3));
+
+	switch (offset & 0x3) {
+	case 2:
+		val32 &= ~0xFFFF0000;
+		val32 |= (u32)val << 16;
+		break;
+	case 0:
+	default:
+		val32 &= ~0xFFFF;
+		val32 |= val;
+		break;
+	}
+	writel(val32, addr + (offset & ~0x3));
+}
+
+static inline void xgene_pcie_cfg_out8(void __iomem *addr, int offset, u8 val)
+{
+	u32 val32 = readl(addr + (offset & ~0x3));
+
+	switch (offset & 0x3) {
+	case 0:
+		val32 &= ~0xFF;
+		val32 |= val;
+		break;
+	case 1:
+		val32 &= ~0xFF00;
+		val32 |= (u32)val << 8;
+		break;
+	case 2:
+		val32 &= ~0xFF0000;
+		val32 |= (u32)val << 16;
+		break;
+	case 3:
+	default:
+		val32 &= ~0xFF000000;
+		val32 |= (u32)val << 24;
+		break;
+	}
+	writel(val32, addr + (offset & ~0x3));
+}
+
+static inline void xgene_pcie_cfg_in32(void __iomem *addr, int offset, u32 *val)
+{
+	*val = readl(addr + offset);
+}
+
+static inline void xgene_pcie_cfg_in16(void __iomem *addr, int offset, u32 *val)
+{
+	*val = readl(addr + (offset & ~0x3));
+
+	switch (offset & 0x3) {
+	case 2:
+		*val >>= 16;
+		break;
+	}
+
+	*val &= 0xFFFF;
+}
+
+static inline void xgene_pcie_cfg_in8(void __iomem *addr, int offset, u32 *val)
+{
+	*val = readl(addr + (offset & ~0x3));
+
+	switch (offset & 0x3) {
+	case 3:
+		*val = *val >> 24;
+		break;
+	case 2:
+		*val = *val >> 16;
+		break;
+	case 1:
+		*val = *val >> 8;
+		break;
+	}
+	*val &= 0xFF;
+}
+
+/*
+ * When the address bit [17:16] is 2'b01, the Configuration access will be
+ * treated as Type 1 and it will be forwarded to external PCIe device.
+ */
+static void __iomem *xgene_pcie_get_cfg_base(struct pci_bus *bus)
+{
+	struct xgene_pcie_port *port = bus->sysdata;
+
+	if (bus->number >= (bus->primary + 1))
+		return port->cfg_base + AXI_EP_CFG_ACCESS;
+
+	return port->cfg_base;
+}
+
+/*
+ * For Configuration request, RTDID register is used as Bus Number,
+ * Device Number and Function number of the header fields.
+ */
+static void xgene_pcie_set_rtdid_reg(struct pci_bus *bus, uint devfn)
+{
+	struct xgene_pcie_port *port = bus->sysdata;
+	unsigned int b, d, f;
+	u32 rtdid_val = 0;
+
+	b = bus->number;
+	d = PCI_SLOT(devfn);
+	f = PCI_FUNC(devfn);
+
+	if (!pci_is_root_bus(bus))
+		rtdid_val = (b << 8) | (d << 3) | f;
+
+	writel(rtdid_val, port->csr_base + RTDID);
+	/* read the register back to ensure flush */
+	readl(port->csr_base + RTDID);
+}
+
+/*
+ * X-Gene PCIe port uses BAR0-BAR1 of RC's configuration space as
+ * the translation from PCI bus to native BUS.  Entire DDR region
+ * is mapped into PCIe space using these registers, so it can be
+ * reached by DMA from EP devices.  The BAR0/1 of bridge should be
+ * hidden during enumeration to avoid the sizing and resource allocation
+ * by PCIe core.
+ */
+static bool xgene_pcie_hide_rc_bars(struct pci_bus *bus, int offset)
+{
+	if (pci_is_root_bus(bus) && ((offset == PCI_BASE_ADDRESS_0) ||
+				     (offset == PCI_BASE_ADDRESS_1)))
+		return true;
+
+	return false;
+}
+
+static int xgene_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
+				  int offset, int len, u32 *val)
+{
+	struct xgene_pcie_port *port = bus->sysdata;
+	void __iomem *addr;
+
+	if ((pci_is_root_bus(bus) && devfn != 0) || !port->link_up)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	if (xgene_pcie_hide_rc_bars(bus, offset)) {
+		*val = 0;
+		return PCIBIOS_SUCCESSFUL;
+	}
+
+	xgene_pcie_set_rtdid_reg(bus, devfn);
+	addr = xgene_pcie_get_cfg_base(bus);
+	switch (len) {
+	case 1:
+		xgene_pcie_cfg_in8(addr, offset, val);
+		break;
+	case 2:
+		xgene_pcie_cfg_in16(addr, offset, val);
+		break;
+	default:
+		xgene_pcie_cfg_in32(addr, offset, val);
+		break;
+	}
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int xgene_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
+				   int offset, int len, u32 val)
+{
+	struct xgene_pcie_port *port = bus->sysdata;
+	void __iomem *addr;
+
+	if ((pci_is_root_bus(bus) && devfn != 0) || !port->link_up)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	if (xgene_pcie_hide_rc_bars(bus, offset))
+		return PCIBIOS_SUCCESSFUL;
+
+	xgene_pcie_set_rtdid_reg(bus, devfn);
+	addr = xgene_pcie_get_cfg_base(bus);
+	switch (len) {
+	case 1:
+		xgene_pcie_cfg_out8(addr, offset, (u8)val);
+		break;
+	case 2:
+		xgene_pcie_cfg_out16(addr, offset, (u16)val);
+		break;
+	default:
+		xgene_pcie_cfg_out32(addr, offset, val);
+		break;
+	}
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static struct pci_ops xgene_pcie_ops = {
+	.read = xgene_pcie_read_config,
+	.write = xgene_pcie_write_config
+};
+
+static u64 xgene_pcie_set_ib_mask(void __iomem *csr_base, u32 addr,
+				  u32 flags, u64 size)
+{
+	u64 mask = (~(size - 1) & PCI_BASE_ADDRESS_MEM_MASK) | flags;
+	u32 val32 = 0;
+	u32 val;
+
+	val32 = readl(csr_base + addr);
+	val = (val32 & 0x0000ffff) | (lower_32_bits(mask) << 16);
+	writel(val, csr_base + addr);
+
+	val32 = readl(csr_base + addr + 0x04);
+	val = (val32 & 0xffff0000) | (lower_32_bits(mask) >> 16);
+	writel(val, csr_base + addr + 0x04);
+
+	val32 = readl(csr_base + addr + 0x04);
+	val = (val32 & 0x0000ffff) | (upper_32_bits(mask) << 16);
+	writel(val, csr_base + addr + 0x04);
+
+	val32 = readl(csr_base + addr + 0x08);
+	val = (val32 & 0xffff0000) | (upper_32_bits(mask) >> 16);
+	writel(val, csr_base + addr + 0x08);
+
+	return mask;
+}
+
+static void xgene_pcie_linkup(struct xgene_pcie_port *port,
+				   u32 *lanes, u32 *speed)
+{
+	void __iomem *csr_base = port->csr_base;
+	u32 val32;
+
+	port->link_up = false;
+	val32 = readl(csr_base + PCIECORE_CTLANDSTATUS);
+	if (val32 & LINK_UP_MASK) {
+		port->link_up = true;
+		*speed = PIPE_PHY_RATE_RD(val32);
+		val32 = readl(csr_base + BRIDGE_STATUS_0);
+		*lanes = val32 >> 26;
+	}
+}
+
+static int xgene_pcie_init_port(struct xgene_pcie_port *port)
+{
+	int rc;
+
+	port->clk = clk_get(port->dev, NULL);
+	if (IS_ERR(port->clk)) {
+		dev_err(port->dev, "clock not available\n");
+		return -ENODEV;
+	}
+
+	rc = clk_prepare_enable(port->clk);
+	if (rc) {
+		dev_err(port->dev, "clock enable failed\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static int xgene_pcie_map_reg(struct xgene_pcie_port *port,
+			      struct platform_device *pdev)
+{
+	struct resource *res;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
+	port->csr_base = devm_ioremap_resource(port->dev, res);
+	if (IS_ERR(port->csr_base))
+		return PTR_ERR(port->csr_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
+	port->cfg_base = devm_ioremap_resource(port->dev, res);
+	if (IS_ERR(port->cfg_base))
+		return PTR_ERR(port->cfg_base);
+	port->cfg_addr = res->start;
+
+	return 0;
+}
+
+static void xgene_pcie_setup_ob_reg(struct xgene_pcie_port *port,
+				    struct resource *res, u32 offset,
+				    u64 cpu_addr, u64 pci_addr)
+{
+	void __iomem *base = port->csr_base + offset;
+	resource_size_t size = resource_size(res);
+	u64 restype = resource_type(res);
+	u64 mask = 0;
+	u32 min_size;
+	u32 flag = EN_REG;
+
+	if (restype == IORESOURCE_MEM) {
+		min_size = SZ_128M;
+	} else {
+		min_size = 128;
+		flag |= OB_LO_IO;
+	}
+
+	if (size >= min_size)
+		mask = ~(size - 1) | flag;
+	else
+		dev_warn(port->dev, "res size 0x%llx less than minimum 0x%x\n",
+			 (u64)size, min_size);
+
+	writel(lower_32_bits(cpu_addr), base);
+	writel(upper_32_bits(cpu_addr), base + 0x04);
+	writel(lower_32_bits(mask), base + 0x08);
+	writel(upper_32_bits(mask), base + 0x0c);
+	writel(lower_32_bits(pci_addr), base + 0x10);
+	writel(upper_32_bits(pci_addr), base + 0x14);
+}
+
+static void xgene_pcie_setup_cfg_reg(void __iomem *csr_base, u64 addr)
+{
+	writel(lower_32_bits(addr), csr_base + CFGBARL);
+	writel(upper_32_bits(addr), csr_base + CFGBARH);
+	writel(EN_REG, csr_base + CFGCTL);
+}
+
+static int xgene_pcie_map_ranges(struct xgene_pcie_port *port,
+				 struct list_head *res,
+				 resource_size_t io_base)
+{
+	struct pci_host_bridge_window *window;
+	struct device *dev = port->dev;
+	int ret;
+
+	list_for_each_entry(window, res, list) {
+		struct resource *res = window->res;
+		u64 restype = resource_type(res);
+
+		dev_dbg(port->dev, "%pR\n", res);
+
+		switch (restype) {
+		case IORESOURCE_IO:
+			xgene_pcie_setup_ob_reg(port, res, OMR3BARL, io_base,
+						res->start - window->offset);
+			ret = pci_remap_iospace(res, io_base);
+			if (ret < 0)
+				return ret;
+			break;
+		case IORESOURCE_MEM:
+			xgene_pcie_setup_ob_reg(port, res, OMR1BARL, res->start,
+						res->start - window->offset);
+			break;
+		case IORESOURCE_BUS:
+			break;
+		default:
+			dev_err(dev, "invalid resource %pR\n", res);
+			return -EINVAL;
+		}
+	}
+	xgene_pcie_setup_cfg_reg(port->csr_base, port->cfg_addr);
+
+	return 0;
+}
+
+static void xgene_pcie_setup_pims(void *addr, u64 pim, u64 size)
+{
+	writel(lower_32_bits(pim), addr);
+	writel(upper_32_bits(pim) | EN_COHERENCY, addr + 0x04);
+	writel(lower_32_bits(size), addr + 0x10);
+	writel(upper_32_bits(size), addr + 0x14);
+}
+
+/*
+ * X-Gene PCIe support maximum 3 inbound memory regions
+ * This function helps to select a region based on size of region
+ */
+static int xgene_pcie_select_ib_reg(u8 *ib_reg_mask, u64 size)
+{
+	if ((size > 4) && (size < SZ_16M) && !(*ib_reg_mask & (1 << 1))) {
+		*ib_reg_mask |= (1 << 1);
+		return 1;
+	}
+
+	if ((size > SZ_1K) && (size < SZ_1T) && !(*ib_reg_mask & (1 << 0))) {
+		*ib_reg_mask |= (1 << 0);
+		return 0;
+	}
+
+	if ((size > SZ_1M) && (size < SZ_1T) && !(*ib_reg_mask & (1 << 2))) {
+		*ib_reg_mask |= (1 << 2);
+		return 2;
+	}
+
+	return -EINVAL;
+}
+
+static void xgene_pcie_setup_ib_reg(struct xgene_pcie_port *port,
+				    struct of_pci_range *range, u8 *ib_reg_mask)
+{
+	void __iomem *csr_base = port->csr_base;
+	void __iomem *cfg_base = port->cfg_base;
+	void *bar_addr;
+	void *pim_addr;
+	u64 cpu_addr = range->cpu_addr;
+	u64 pci_addr = range->pci_addr;
+	u64 size = range->size;
+	u64 mask = ~(size - 1) | EN_REG;
+	u32 flags = PCI_BASE_ADDRESS_MEM_TYPE_64;
+	u32 bar_low;
+	int region;
+
+	region = xgene_pcie_select_ib_reg(ib_reg_mask, range->size);
+	if (region < 0) {
+		dev_warn(port->dev, "invalid pcie dma-range config\n");
+		return;
+	}
+
+	if (range->flags & IORESOURCE_PREFETCH)
+		flags |= PCI_BASE_ADDRESS_MEM_PREFETCH;
+
+	bar_low = pcie_bar_low_val((u32)cpu_addr, flags);
+	switch (region) {
+	case 0:
+		xgene_pcie_set_ib_mask(csr_base, BRIDGE_CFG_4, flags, size);
+		bar_addr = cfg_base + PCI_BASE_ADDRESS_0;
+		writel(bar_low, bar_addr);
+		writel(upper_32_bits(cpu_addr), bar_addr + 0x4);
+		pim_addr = csr_base + PIM1_1L;
+		break;
+	case 1:
+		bar_addr = csr_base + IBAR2;
+		writel(bar_low, bar_addr);
+		writel(lower_32_bits(mask), csr_base + IR2MSK);
+		pim_addr = csr_base + PIM2_1L;
+		break;
+	case 2:
+		bar_addr = csr_base + IBAR3L;
+		writel(bar_low, bar_addr);
+		writel(upper_32_bits(cpu_addr), bar_addr + 0x4);
+		writel(lower_32_bits(mask), csr_base + IR3MSKL);
+		writel(upper_32_bits(mask), csr_base + IR3MSKL + 0x4);
+		pim_addr = csr_base + PIM3_1L;
+		break;
+	}
+
+	xgene_pcie_setup_pims(pim_addr, pci_addr, ~(size - 1));
+}
+
+static int pci_dma_range_parser_init(struct of_pci_range_parser *parser,
+				     struct device_node *node)
+{
+	const int na = 3, ns = 2;
+	int rlen;
+
+	parser->node = node;
+	parser->pna = of_n_addr_cells(node);
+	parser->np = parser->pna + na + ns;
+
+	parser->range = of_get_property(node, "dma-ranges", &rlen);
+	if (!parser->range)
+		return -ENOENT;
+	parser->end = parser->range + rlen / sizeof(__be32);
+
+	return 0;
+}
+
+static int xgene_pcie_parse_map_dma_ranges(struct xgene_pcie_port *port)
+{
+	struct device_node *np = port->node;
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	struct device *dev = port->dev;
+	u8 ib_reg_mask = 0;
+
+	if (pci_dma_range_parser_init(&parser, np)) {
+		dev_err(dev, "missing dma-ranges property\n");
+		return -EINVAL;
+	}
+
+	/* Get the dma-ranges from DT */
+	for_each_of_pci_range(&parser, &range) {
+		u64 end = range.cpu_addr + range.size - 1;
+
+		dev_dbg(port->dev, "0x%08x 0x%016llx..0x%016llx -> 0x%016llx\n",
+			range.flags, range.cpu_addr, end, range.pci_addr);
+		xgene_pcie_setup_ib_reg(port, &range, &ib_reg_mask);
+	}
+	return 0;
+}
+
+/* clear BAR configuration which was done by firmware */
+static void xgene_pcie_clear_config(struct xgene_pcie_port *port)
+{
+	int i;
+
+	for (i = PIM1_1L; i <= CFGCTL; i += 4)
+		writel(0x0, port->csr_base + i);
+}
+
+static int xgene_pcie_setup(struct xgene_pcie_port *port,
+			    struct list_head *res,
+			    resource_size_t io_base)
+{
+	u32 val, lanes = 0, speed = 0;
+	int ret;
+
+	xgene_pcie_clear_config(port);
+
+	/* setup the vendor and device IDs correctly */
+	val = (XGENE_PCIE_DEVICEID << 16) | XGENE_PCIE_VENDORID;
+	writel(val, port->csr_base + BRIDGE_CFG_0);
+
+	ret = xgene_pcie_map_ranges(port, res, io_base);
+	if (ret)
+		return ret;
+
+	ret = xgene_pcie_parse_map_dma_ranges(port);
+	if (ret)
+		return ret;
+
+	xgene_pcie_linkup(port, &lanes, &speed);
+	if (!port->link_up)
+		dev_info(port->dev, "(rc) link down\n");
+	else
+		dev_info(port->dev, "(rc) x%d gen-%d link up\n",
+				lanes, speed + 1);
+	return 0;
+}
+
+static int xgene_pcie_probe_bridge(struct platform_device *pdev)
+{
+	struct device_node *dn = pdev->dev.of_node;
+	struct xgene_pcie_port *port;
+	resource_size_t iobase = 0;
+	struct pci_bus *bus;
+	int ret;
+	LIST_HEAD(res);
+
+	port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+	port->node = of_node_get(pdev->dev.of_node);
+	port->dev = &pdev->dev;
+
+	ret = xgene_pcie_map_reg(port, pdev);
+	if (ret)
+		return ret;
+
+	ret = xgene_pcie_init_port(port);
+	if (ret)
+		return ret;
+
+	ret = of_pci_get_host_bridge_resources(dn, 0, 0xff, &res, &iobase);
+	if (ret)
+		return ret;
+
+	ret = xgene_pcie_setup(port, &res, iobase);
+	if (ret)
+		return ret;
+
+	bus = pci_scan_root_bus(&pdev->dev, 0, &xgene_pcie_ops, port, &res);
+	if (!bus)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, port);
+	return 0;
+}
+
+static const struct of_device_id xgene_pcie_match_table[] = {
+	{.compatible = "apm,xgene-pcie",},
+	{},
+};
+
+static struct platform_driver xgene_pcie_driver = {
+	.driver = {
+		   .name = "xgene-pcie",
+		   .owner = THIS_MODULE,
+		   .of_match_table = of_match_ptr(xgene_pcie_match_table),
+	},
+	.probe = xgene_pcie_probe_bridge,
+};
+module_platform_driver(xgene_pcie_driver);
+
+MODULE_AUTHOR("Tanmay Inamdar <tinamdar@apm.com>");
+MODULE_DESCRIPTION("APM X-Gene PCIe driver");
+MODULE_LICENSE("GPL v2");