PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver

Add a driver for Mobiveil AXI PCIe Host Bridge Soft IP - GPEX 4.0,
a PCIe gen4 IP. This IP has upto 8 outbound and inbound windows
for the address translation.
Signed-off-by: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: fold in mobiveil_pcie_of_match[] NULL termination from Wei
Yongjun <weiyongjun1@huawei.com>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>

drivers/pci/host/pcie-mobiveil.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host controller driver for Mobiveil PCIe Host controller
+ *
+ * Copyright (c) 2018 Mobiveil Inc.
+ * Author: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* register offsets and bit positions */
+
+/*
+ * translation tables are grouped into windows, each window registers are
+ * grouped into blocks of 4 or 16 registers each
+ */
+#define PAB_REG_BLOCK_SIZE	16
+#define PAB_EXT_REG_BLOCK_SIZE	4
+
+#define PAB_REG_ADDR(offset, win) (offset + (win * PAB_REG_BLOCK_SIZE))
+#define PAB_EXT_REG_ADDR(offset, win) (offset + (win * PAB_EXT_REG_BLOCK_SIZE))
+
+#define LTSSM_STATUS		0x0404
+#define  LTSSM_STATUS_L0_MASK	0x3f
+#define  LTSSM_STATUS_L0	0x2d
+
+#define PAB_CTRL		0x0808
+#define  AMBA_PIO_ENABLE_SHIFT	0
+#define  PEX_PIO_ENABLE_SHIFT	1
+#define  PAGE_SEL_SHIFT	13
+#define  PAGE_SEL_MASK		0x3f
+#define  PAGE_LO_MASK		0x3ff
+#define  PAGE_SEL_EN		0xc00
+#define  PAGE_SEL_OFFSET_SHIFT	10
+
+#define PAB_AXI_PIO_CTRL	0x0840
+#define  APIO_EN_MASK		0xf
+
+#define PAB_PEX_PIO_CTRL	0x08c0
+#define  PIO_ENABLE_SHIFT	0
+
+#define PAB_INTP_AMBA_MISC_ENB		0x0b0c
+#define PAB_INTP_AMBA_MISC_STAT	0x0b1c
+#define  PAB_INTP_INTX_MASK		0x01e0
+
+#define PAB_AXI_AMAP_CTRL(win)	PAB_REG_ADDR(0x0ba0, win)
+#define  WIN_ENABLE_SHIFT	0
+#define  WIN_TYPE_SHIFT	1
+
+#define PAB_EXT_AXI_AMAP_SIZE(win)	PAB_EXT_REG_ADDR(0xbaf0, win)
+
+#define PAB_AXI_AMAP_AXI_WIN(win)	PAB_REG_ADDR(0x0ba4, win)
+#define  AXI_WINDOW_ALIGN_MASK		3
+
+#define PAB_AXI_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR(0x0ba8, win)
+#define  PAB_BUS_SHIFT		24
+#define  PAB_DEVICE_SHIFT	19
+#define  PAB_FUNCTION_SHIFT	16
+
+#define PAB_AXI_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR(0x0bac, win)
+#define PAB_INTP_AXI_PIO_CLASS		0x474
+
+#define PAB_PEX_AMAP_CTRL(win)	PAB_REG_ADDR(0x4ba0, win)
+#define  AMAP_CTRL_EN_SHIFT	0
+#define  AMAP_CTRL_TYPE_SHIFT	1
+
+#define PAB_EXT_PEX_AMAP_SIZEN(win)	PAB_EXT_REG_ADDR(0xbef0, win)
+#define PAB_PEX_AMAP_AXI_WIN(win)	PAB_REG_ADDR(0x4ba4, win)
+#define PAB_PEX_AMAP_PEX_WIN_L(win)	PAB_REG_ADDR(0x4ba8, win)
+#define PAB_PEX_AMAP_PEX_WIN_H(win)	PAB_REG_ADDR(0x4bac, win)
+
+/* starting offset of INTX bits in status register */
+#define PAB_INTX_START	5
+
+/* outbound and inbound window definitions */
+#define WIN_NUM_0		0
+#define WIN_NUM_1		1
+#define CFG_WINDOW_TYPE	0
+#define IO_WINDOW_TYPE		1
+#define MEM_WINDOW_TYPE	2
+#define IB_WIN_SIZE		(256 * 1024 * 1024 * 1024)
+#define MAX_PIO_WINDOWS	8
+
+/* Parameters for the waiting for link up routine */
+#define LINK_WAIT_MAX_RETRIES	10
+#define LINK_WAIT_MIN	90000
+#define LINK_WAIT_MAX	100000
+
+struct mobiveil_pcie {
+	struct platform_device *pdev;
+	struct list_head resources;
+	void __iomem *config_axi_slave_base;	/* endpoint config base */
+	void __iomem *csr_axi_slave_base;	/* root port config base */
+	void __iomem *pcie_reg_base;	/* Physical PCIe Controller Base */
+	struct irq_domain *intx_domain;
+	raw_spinlock_t intx_mask_lock;
+	int irq;
+	int apio_wins;
+	int ppio_wins;
+	int ob_wins_configured;		/* configured outbound windows */
+	int ib_wins_configured;		/* configured inbound windows */
+	struct resource *ob_io_res;
+	char root_bus_nr;
+};
+
+static inline void csr_writel(struct mobiveil_pcie *pcie, const u32 value,
+		const u32 reg)
+{
+	writel_relaxed(value, pcie->csr_axi_slave_base + reg);
+}
+
+static inline u32 csr_readl(struct mobiveil_pcie *pcie, const u32 reg)
+{
+	return readl_relaxed(pcie->csr_axi_slave_base + reg);
+}
+
+static bool mobiveil_pcie_link_up(struct mobiveil_pcie *pcie)
+{
+	return (csr_readl(pcie, LTSSM_STATUS) &
+		LTSSM_STATUS_L0_MASK) == LTSSM_STATUS_L0;
+}
+
+static bool mobiveil_pcie_valid_device(struct pci_bus *bus, unsigned int devfn)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	/* Only one device down on each root port */
+	if ((bus->number == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	/*
+	 * Do not read more than one device on the bus directly
+	 * attached to RC
+	 */
+	if ((bus->primary == pcie->root_bus_nr) && (devfn > 0))
+		return false;
+
+	return true;
+}
+
+/*
+ * mobiveil_pcie_map_bus - routine to get the configuration base of either
+ * root port or endpoint
+ */
+static void __iomem *mobiveil_pcie_map_bus(struct pci_bus *bus,
+					unsigned int devfn, int where)
+{
+	struct mobiveil_pcie *pcie = bus->sysdata;
+
+	if (!mobiveil_pcie_valid_device(bus, devfn))
+		return NULL;
+
+	if (bus->number == pcie->root_bus_nr) {
+		/* RC config access */
+		return pcie->csr_axi_slave_base + where;
+	}
+
+	/*
+	 * EP config access (in Config/APIO space)
+	 * Program PEX Address base (31..16 bits) with appropriate value
+	 * (BDF) in PAB_AXI_AMAP_PEX_WIN_L0 Register.
+	 * Relies on pci_lock serialization
+	 */
+	csr_writel(pcie, bus->number << PAB_BUS_SHIFT |
+			PCI_SLOT(devfn) << PAB_DEVICE_SHIFT |
+			PCI_FUNC(devfn) << PAB_FUNCTION_SHIFT,
+			PAB_AXI_AMAP_PEX_WIN_L(WIN_NUM_0));
+	return pcie->config_axi_slave_base + where;
+}
+
+static struct pci_ops mobiveil_pcie_ops = {
+	.map_bus = mobiveil_pcie_map_bus,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+static void mobiveil_pcie_isr(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct mobiveil_pcie *pcie = irq_desc_get_handler_data(desc);
+	struct device *dev = &pcie->pdev->dev;
+	u32 intr_status;
+	unsigned long shifted_status;
+	u32 bit, virq, val, mask;
+
+	/*
+	 * The core provides interrupt for INTx.
+	 * So we'll read INTx status.
+	 */
+
+	chained_irq_enter(chip, desc);
+
+	/* read INTx status */
+	val = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT);
+	mask = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	intr_status = val & mask;
+
+	/* Handle INTx */
+	if (intr_status & PAB_INTP_INTX_MASK) {
+		shifted_status = csr_readl(pcie, PAB_INTP_AMBA_MISC_STAT) >>
+			PAB_INTX_START;
+		do {
+			for_each_set_bit(bit, &shifted_status, PCI_NUM_INTX) {
+				virq = irq_find_mapping(pcie->intx_domain,
+						bit + 1);
+				if (virq)
+					generic_handle_irq(virq);
+				else
+					dev_err_ratelimited(dev,
+						"unexpected IRQ, INT%d\n", bit);
+
+				/* clear interrupt */
+				csr_writel(pcie,
+					shifted_status << PAB_INTX_START,
+					PAB_INTP_AMBA_MISC_STAT);
+			}
+		} while ((shifted_status >> PAB_INTX_START) != 0);
+	}
+
+	/* Clear the interrupt status */
+	csr_writel(pcie, intr_status, PAB_INTP_AMBA_MISC_STAT);
+	chained_irq_exit(chip, desc);
+}
+
+static int mobiveil_pcie_parse_dt(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct platform_device *pdev = pcie->pdev;
+	struct device_node *node = dev->of_node;
+	struct resource *res;
+	const char *type;
+
+	type = of_get_property(node, "device_type", NULL);
+	if (!type || strcmp(type, "pci")) {
+		dev_err(dev, "invalid \"device_type\" %s\n", type);
+		return -EINVAL;
+	}
+
+	/* map config resource */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+			"config_axi_slave");
+	pcie->config_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->config_axi_slave_base))
+		return PTR_ERR(pcie->config_axi_slave_base);
+	pcie->ob_io_res = res;
+
+	/* map csr resource */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+			"csr_axi_slave");
+	pcie->csr_axi_slave_base = devm_pci_remap_cfg_resource(dev, res);
+	if (IS_ERR(pcie->csr_axi_slave_base))
+		return PTR_ERR(pcie->csr_axi_slave_base);
+	pcie->pcie_reg_base = res->start;
+
+	/* read the number of windows requested */
+	if (of_property_read_u32(node, "apio-wins", &pcie->apio_wins))
+		pcie->apio_wins = MAX_PIO_WINDOWS;
+
+	if (of_property_read_u32(node, "ppio-wins", &pcie->ppio_wins))
+		pcie->ppio_wins = MAX_PIO_WINDOWS;
+
+	pcie->irq = platform_get_irq(pdev, 0);
+	if (pcie->irq <= 0) {
+		dev_err(dev, "failed to map IRQ: %d\n", pcie->irq);
+		return -ENODEV;
+	}
+
+	irq_set_chained_handler_and_data(pcie->irq, mobiveil_pcie_isr, pcie);
+
+	return 0;
+}
+
+/*
+ * select_paged_register - routine to access paged register of root complex
+ *
+ * registers of RC are paged, for this scheme to work
+ * extracted higher 6 bits of the offset will be written to pg_sel
+ * field of PAB_CTRL register and rest of the lower 10 bits enabled with
+ * PAGE_SEL_EN are used as offset of the register.
+ */
+static void select_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	int pab_ctrl_dw, pg_sel;
+
+	/* clear pg_sel field */
+	pab_ctrl_dw = csr_readl(pcie, PAB_CTRL);
+	pab_ctrl_dw = (pab_ctrl_dw & ~(PAGE_SEL_MASK << PAGE_SEL_SHIFT));
+
+	/* set pg_sel field */
+	pg_sel = (offset >> PAGE_SEL_OFFSET_SHIFT) & PAGE_SEL_MASK;
+	pab_ctrl_dw |= ((pg_sel << PAGE_SEL_SHIFT));
+	csr_writel(pcie, pab_ctrl_dw, PAB_CTRL);
+}
+
+static void write_paged_register(struct mobiveil_pcie *pcie,
+		u32 val, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	csr_writel(pcie, val, off);
+}
+
+static u32 read_paged_register(struct mobiveil_pcie *pcie, u32 offset)
+{
+	u32 off = (offset & PAGE_LO_MASK) | PAGE_SEL_EN;
+
+	select_paged_register(pcie, offset);
+	return csr_readl(pcie, off);
+}
+
+static void program_ib_windows(struct mobiveil_pcie *pcie, int win_num,
+		int pci_addr, u32 type, u64 size)
+{
+	int pio_ctrl_val;
+	int amap_ctrl_dw;
+	u64 size64 = ~(size - 1);
+
+	if ((pcie->ib_wins_configured + 1) > pcie->ppio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max inbound windows reached !\n");
+		return;
+	}
+
+	pio_ctrl_val = csr_readl(pcie, PAB_PEX_PIO_CTRL);
+	csr_writel(pcie,
+		pio_ctrl_val | (1 << PIO_ENABLE_SHIFT), PAB_PEX_PIO_CTRL);
+	amap_ctrl_dw = read_paged_register(pcie, PAB_PEX_AMAP_CTRL(win_num));
+	amap_ctrl_dw = (amap_ctrl_dw | (type << AMAP_CTRL_TYPE_SHIFT));
+	amap_ctrl_dw = (amap_ctrl_dw | (1 << AMAP_CTRL_EN_SHIFT));
+
+	write_paged_register(pcie, amap_ctrl_dw | lower_32_bits(size64),
+				PAB_PEX_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_PEX_AMAP_SIZEN(win_num));
+
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_AXI_WIN(win_num));
+	write_paged_register(pcie, pci_addr, PAB_PEX_AMAP_PEX_WIN_L(win_num));
+	write_paged_register(pcie, 0, PAB_PEX_AMAP_PEX_WIN_H(win_num));
+}
+
+/*
+ * routine to program the outbound windows
+ */
+static void program_ob_windows(struct mobiveil_pcie *pcie, int win_num,
+		u64 cpu_addr, u64 pci_addr, u32 config_io_bit, u64 size)
+{
+
+	u32 value, type;
+	u64 size64 = ~(size - 1);
+
+	if ((pcie->ob_wins_configured + 1) > pcie->apio_wins) {
+		dev_err(&pcie->pdev->dev,
+			"ERROR: max outbound windows reached !\n");
+		return;
+	}
+
+	/*
+	 * program Enable Bit to 1, Type Bit to (00) base 2, AXI Window Size Bit
+	 * to 4 KB in PAB_AXI_AMAP_CTRL register
+	 */
+	type = config_io_bit;
+	value = csr_readl(pcie, PAB_AXI_AMAP_CTRL(win_num));
+	csr_writel(pcie, 1 << WIN_ENABLE_SHIFT | type << WIN_TYPE_SHIFT |
+			lower_32_bits(size64), PAB_AXI_AMAP_CTRL(win_num));
+
+	write_paged_register(pcie, upper_32_bits(size64),
+				PAB_EXT_AXI_AMAP_SIZE(win_num));
+
+	/*
+	 * program AXI window base with appropriate value in
+	 * PAB_AXI_AMAP_AXI_WIN0 register
+	 */
+	value = csr_readl(pcie, PAB_AXI_AMAP_AXI_WIN(win_num));
+	csr_writel(pcie, cpu_addr & (~AXI_WINDOW_ALIGN_MASK),
+			PAB_AXI_AMAP_AXI_WIN(win_num));
+
+	value = csr_readl(pcie, PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	csr_writel(pcie, lower_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_L(win_num));
+	csr_writel(pcie, upper_32_bits(pci_addr),
+			PAB_AXI_AMAP_PEX_WIN_H(win_num));
+
+	pcie->ob_wins_configured++;
+}
+
+static int mobiveil_bringup_link(struct mobiveil_pcie *pcie)
+{
+	int retries;
+
+	/* check if the link is up or not */
+	for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) {
+		if (mobiveil_pcie_link_up(pcie))
+			return 0;
+
+		usleep_range(LINK_WAIT_MIN, LINK_WAIT_MAX);
+	}
+	dev_err(&pcie->pdev->dev, "link never came up\n");
+	return -ETIMEDOUT;
+}
+
+static int mobiveil_host_init(struct mobiveil_pcie *pcie)
+{
+	u32 value, pab_ctrl, type = 0;
+	int err;
+	struct resource_entry *win, *tmp;
+
+	err = mobiveil_bringup_link(pcie);
+	if (err) {
+		dev_info(&pcie->pdev->dev, "link bring-up failed\n");
+		return err;
+	}
+
+	/*
+	 * program Bus Master Enable Bit in Command Register in PAB Config
+	 * Space
+	 */
+	value = csr_readl(pcie, PCI_COMMAND);
+	csr_writel(pcie, value | PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
+		PCI_COMMAND_MASTER, PCI_COMMAND);
+
+	/*
+	 * program PIO Enable Bit to 1 (and PEX PIO Enable to 1) in PAB_CTRL
+	 * register
+	 */
+	pab_ctrl = csr_readl(pcie, PAB_CTRL);
+	csr_writel(pcie, pab_ctrl | (1 << AMBA_PIO_ENABLE_SHIFT) |
+		(1 << PEX_PIO_ENABLE_SHIFT), PAB_CTRL);
+
+	csr_writel(pcie, PAB_INTP_INTX_MASK, PAB_INTP_AMBA_MISC_ENB);
+
+	/*
+	 * program PIO Enable Bit to 1 and Config Window Enable Bit to 1 in
+	 * PAB_AXI_PIO_CTRL Register
+	 */
+	value = csr_readl(pcie, PAB_AXI_PIO_CTRL);
+	csr_writel(pcie, value | APIO_EN_MASK, PAB_AXI_PIO_CTRL);
+
+	/*
+	 * we'll program one outbound window for config reads and
+	 * another default inbound window for all the upstream traffic
+	 * rest of the outbound windows will be configured according to
+	 * the "ranges" field defined in device tree
+	 */
+
+	/* config outbound translation window */
+	program_ob_windows(pcie, pcie->ob_wins_configured,
+			pcie->ob_io_res->start, 0, CFG_WINDOW_TYPE,
+			resource_size(pcie->ob_io_res));
+
+	/* memory inbound translation window */
+	program_ib_windows(pcie, WIN_NUM_1, 0, MEM_WINDOW_TYPE, IB_WIN_SIZE);
+
+	/* Get the I/O and memory ranges from DT */
+	resource_list_for_each_entry_safe(win, tmp, &pcie->resources) {
+		type = 0;
+		if (resource_type(win->res) == IORESOURCE_MEM)
+			type = MEM_WINDOW_TYPE;
+		if (resource_type(win->res) == IORESOURCE_IO)
+			type = IO_WINDOW_TYPE;
+		if (type) {
+			/* configure outbound translation window */
+			program_ob_windows(pcie, pcie->ob_wins_configured,
+				win->res->start, 0, type,
+				resource_size(win->res));
+		}
+	}
+
+	return err;
+}
+
+static void mobiveil_mask_intx_irq(struct irq_data *data)
+{
+	struct irq_desc *desc = irq_to_desc(data->irq);
+	struct mobiveil_pcie *pcie;
+	unsigned long flags;
+	u32 mask, shifted_val;
+
+	pcie = irq_desc_get_chip_data(desc);
+	mask = 1 << ((data->hwirq + PAB_INTX_START) - 1);
+	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
+	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	csr_writel(pcie, (shifted_val & (~mask)), PAB_INTP_AMBA_MISC_ENB);
+	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
+}
+
+static void mobiveil_unmask_intx_irq(struct irq_data *data)
+{
+	struct irq_desc *desc = irq_to_desc(data->irq);
+	struct mobiveil_pcie *pcie;
+	unsigned long flags;
+	u32 shifted_val, mask;
+
+	pcie = irq_desc_get_chip_data(desc);
+	mask = 1 << ((data->hwirq + PAB_INTX_START) - 1);
+	raw_spin_lock_irqsave(&pcie->intx_mask_lock, flags);
+	shifted_val = csr_readl(pcie, PAB_INTP_AMBA_MISC_ENB);
+	csr_writel(pcie, (shifted_val | mask), PAB_INTP_AMBA_MISC_ENB);
+	raw_spin_unlock_irqrestore(&pcie->intx_mask_lock, flags);
+}
+
+static struct irq_chip intx_irq_chip = {
+	.name = "mobiveil_pcie:intx",
+	.irq_enable = mobiveil_unmask_intx_irq,
+	.irq_disable = mobiveil_mask_intx_irq,
+	.irq_mask = mobiveil_mask_intx_irq,
+	.irq_unmask = mobiveil_unmask_intx_irq,
+};
+
+/* routine to setup the INTx related data */
+static int mobiveil_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
+		irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &intx_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	return 0;
+}
+
+/* INTx domain operations structure */
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = mobiveil_pcie_intx_map,
+};
+
+static int mobiveil_pcie_init_irq_domain(struct mobiveil_pcie *pcie)
+{
+	struct device *dev = &pcie->pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+
+	/* setup INTx */
+	pcie->intx_domain = irq_domain_add_linear(node,
+				PCI_NUM_INTX, &intx_domain_ops, pcie);
+
+	if (!pcie->intx_domain) {
+		dev_err(dev, "Failed to get a INTx IRQ domain\n");
+		return -ENODEV;
+	}
+
+	raw_spin_lock_init(&pcie->intx_mask_lock);
+
+	return 0;
+}
+
+static int mobiveil_pcie_probe(struct platform_device *pdev)
+{
+	struct mobiveil_pcie *pcie;
+	struct pci_bus *bus;
+	struct pci_bus *child;
+	struct pci_host_bridge *bridge;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	resource_size_t iobase;
+	int ret;
+
+	/* allocate the PCIe port */
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	if (!bridge)
+		return -ENODEV;
+
+	pcie = pci_host_bridge_priv(bridge);
+	if (!pcie)
+		return -ENOMEM;
+
+	pcie->pdev = pdev;
+
+	ret = mobiveil_pcie_parse_dt(pcie);
+	if (ret) {
+		dev_err(dev, "Parsing DT failed, ret: %x\n", ret);
+		return ret;
+	}
+
+	INIT_LIST_HEAD(&pcie->resources);
+
+	/* parse the host bridge base addresses from the device tree file */
+	ret = of_pci_get_host_bridge_resources(node, 0, 0xff,
+			&pcie->resources, &iobase);
+	if (ret) {
+		dev_err(dev, "Getting bridge resources failed\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * configure all inbound and outbound windows and prepare the RC for
+	 * config access
+	 */
+	ret = mobiveil_host_init(pcie);
+	if (ret) {
+		dev_err(dev, "Failed to initialize host\n");
+		goto error;
+	}
+
+	/* fixup for PCIe class register */
+	csr_writel(pcie, 0x060402ab, PAB_INTP_AXI_PIO_CLASS);
+
+	/* initialize the IRQ domains */
+	ret = mobiveil_pcie_init_irq_domain(pcie);
+	if (ret) {
+		dev_err(dev, "Failed creating IRQ Domain\n");
+		goto error;
+	}
+
+	ret = devm_request_pci_bus_resources(dev, &pcie->resources);
+	if (ret)
+		goto error;
+
+	/* Initialize bridge */
+	list_splice_init(&pcie->resources, &bridge->windows);
+	bridge->dev.parent = dev;
+	bridge->sysdata = pcie;
+	bridge->busnr = pcie->root_bus_nr;
+	bridge->ops = &mobiveil_pcie_ops;
+	bridge->map_irq = of_irq_parse_and_map_pci;
+	bridge->swizzle_irq = pci_common_swizzle;
+
+	/* setup the kernel resources for the newly added PCIe root bus */
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret)
+		goto error;
+
+	bus = bridge->bus;
+
+	pci_assign_unassigned_bus_resources(bus);
+	list_for_each_entry(child, &bus->children, node)
+		pcie_bus_configure_settings(child);
+	pci_bus_add_devices(bus);
+
+	return 0;
+error:
+	pci_free_resource_list(&pcie->resources);
+	return ret;
+}
+
+static const struct of_device_id mobiveil_pcie_of_match[] = {
+	{.compatible = "mbvl,gpex40-pcie",},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, mobiveil_pcie_of_match);
+
+static struct platform_driver mobiveil_pcie_driver = {
+	.probe = mobiveil_pcie_probe,
+	.driver = {
+			.name = "mobiveil-pcie",
+			.of_match_table = mobiveil_pcie_of_match,
+			.suppress_bind_attrs = true,
+		},
+};
+
+builtin_platform_driver(mobiveil_pcie_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mobiveil PCIe host controller driver");
+MODULE_AUTHOR("Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>");