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From:   Thippeswamy Havalige <thippeswamy.havalige@amd.com>
To:     <linux-pci@vger.kernel.org>, <devicetree@vger.kernel.org>,
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        <conor+dt@kernel.org>, <thippeswamy.havalige@amd.com>,
        <michal.simek@amd.com>, <bharat.kumar.gogada@amd.com>
Subject: [PATCH v7 RESEND 3/3] PCI: xilinx-xdma: Add Xilinx XDMA Root Port driver
Date:   Tue, 3 Oct 2023 23:04:53 +0530
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Add support for Xilinx XDMA Soft IP core as Root Port.

The Zynq UltraScale+ MPSoCs devices support XDMA soft IP module in
programmable logic.

The integrated XDMA soft IP block has integrated bridge function that
can act as PCIe Root Port.

Signed-off-by: Thippeswamy Havalige <thippeswamy.havalige@amd.com>
Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@amd.com>
---
changes in v7:
- Modify link-up check comments.
- Wrap few lines to 80 columns.
changes in v6:
- Replaced chained irq's with regular interrupts.
- Modified interrupt names.
- Aligned to 80 columns
changes in v5:
- Added detailed comments for link_up check.
- Modified upper case hex values to lower case. 
changes in v4:
- Fixed unsigned integer to integer.
- Fixed return type to EINVAL.
changes in v3:
- Changed license to 2023.
- Added bitfield header to avoid implicit warning.
- Fixed indentation issue.
- Fixed code-style.
changes in v2:
- Remove unnecessary inclusion of headerfiles.
- Added a subset of interrupt error bits to common header files.
- Added pci_is_root_bus function.
- Removed kerneldoc comments of private function.
- Modified of_get_next_child API to of_get_child_by_name.
- Modified of_address_to_resource API to platform_get_resource.
- Modified return value.
---
 drivers/pci/controller/Kconfig              |  11 +
 drivers/pci/controller/Makefile             |   1 +
 drivers/pci/controller/pcie-xilinx-common.h |   1 +
 drivers/pci/controller/pcie-xilinx-dma-pl.c | 803 ++++++++++++++++++++
 4 files changed, 816 insertions(+)
 create mode 100644 drivers/pci/controller/pcie-xilinx-dma-pl.c

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index c0c3f2824990..a3d1f6f16bf4 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -324,6 +324,17 @@ config PCIE_XILINX
 	  Say 'Y' here if you want kernel to support the Xilinx AXI PCIe
 	  Host Bridge driver.
 
+config PCIE_XILINX_DMA_PL
+	bool "Xilinx DMA PL PCIe host bridge support"
+	depends on ARCH_ZYNQMP || COMPILE_TEST
+	depends on PCI_MSI
+	select PCI_HOST_COMMON
+	help
+	  Add support for the Xilinx PL DMA PCIe host bridge,
+	  The controller is soft IP which can act as Root Port.
+	  If you know your system provides Xilinx PCIe host controller
+	  bridge DMA as soft IP say Y; if you are not sure, say N.
+
 config PCIE_XILINX_NWL
 	bool "Xilinx NWL PCIe controller"
 	depends on ARCH_ZYNQMP || COMPILE_TEST
diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
index 37c8663de7fe..f2b19e6174af 100644
--- a/drivers/pci/controller/Makefile
+++ b/drivers/pci/controller/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o
 obj-$(CONFIG_PCIE_XILINX) += pcie-xilinx.o
 obj-$(CONFIG_PCIE_XILINX_NWL) += pcie-xilinx-nwl.o
 obj-$(CONFIG_PCIE_XILINX_CPM) += pcie-xilinx-cpm.o
+obj-$(CONFIG_PCIE_XILINX_DMA_PL) += pcie-xilinx-dma-pl.o
 obj-$(CONFIG_PCI_V3_SEMI) += pci-v3-semi.o
 obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
 obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
diff --git a/drivers/pci/controller/pcie-xilinx-common.h b/drivers/pci/controller/pcie-xilinx-common.h
index e97d27252a08..1832770f3308 100644
--- a/drivers/pci/controller/pcie-xilinx-common.h
+++ b/drivers/pci/controller/pcie-xilinx-common.h
@@ -19,6 +19,7 @@
 #define XILINX_PCIE_INTR_PME_TO_ACK_RCVD	15
 #define XILINX_PCIE_INTR_INTX			16
 #define XILINX_PCIE_INTR_PM_PME_RCVD		17
+#define XILINX_PCIE_INTR_MSI			17
 #define XILINX_PCIE_INTR_SLV_UNSUPP		20
 #define XILINX_PCIE_INTR_SLV_UNEXP		21
 #define XILINX_PCIE_INTR_SLV_COMPL		22
diff --git a/drivers/pci/controller/pcie-xilinx-dma-pl.c b/drivers/pci/controller/pcie-xilinx-dma-pl.c
new file mode 100644
index 000000000000..96639fe47099
--- /dev/null
+++ b/drivers/pci/controller/pcie-xilinx-dma-pl.c
@@ -0,0 +1,803 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PCIe host controller driver for Xilinx XDMA PCIe Bridge
+ *
+ * Copyright (C) 2023 Xilinx, Inc. All rights reserved.
+ */
+#include <linux/bitfield.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+
+#include "../pci.h"
+#include "pcie-xilinx-common.h"
+
+/* Register definitions */
+#define XILINX_PCIE_DMA_REG_IDR			0x00000138
+#define XILINX_PCIE_DMA_REG_IMR			0x0000013c
+#define XILINX_PCIE_DMA_REG_PSCR		0x00000144
+#define XILINX_PCIE_DMA_REG_RPSC		0x00000148
+#define XILINX_PCIE_DMA_REG_MSIBASE1		0x0000014c
+#define XILINX_PCIE_DMA_REG_MSIBASE2		0x00000150
+#define XILINX_PCIE_DMA_REG_RPEFR		0x00000154
+#define XILINX_PCIE_DMA_REG_IDRN		0x00000160
+#define XILINX_PCIE_DMA_REG_IDRN_MASK		0x00000164
+#define XILINX_PCIE_DMA_REG_MSI_LOW		0x00000170
+#define XILINX_PCIE_DMA_REG_MSI_HI		0x00000174
+#define XILINX_PCIE_DMA_REG_MSI_LOW_MASK	0x00000178
+#define XILINX_PCIE_DMA_REG_MSI_HI_MASK		0x0000017c
+
+#define IMR(x) BIT(XILINX_PCIE_INTR_ ##x)
+
+#define XILINX_PCIE_INTR_IMR_ALL_MASK	\
+	(					\
+		IMR(LINK_DOWN)		|	\
+		IMR(HOT_RESET)		|	\
+		IMR(CFG_TIMEOUT)	|	\
+		IMR(CORRECTABLE)	|	\
+		IMR(NONFATAL)		|	\
+		IMR(FATAL)		|	\
+		IMR(INTX)		|	\
+		IMR(MSI)		|	\
+		IMR(SLV_UNSUPP)		|	\
+		IMR(SLV_UNEXP)		|	\
+		IMR(SLV_COMPL)		|	\
+		IMR(SLV_ERRP)		|	\
+		IMR(SLV_CMPABT)		|	\
+		IMR(SLV_ILLBUR)		|	\
+		IMR(MST_DECERR)		|	\
+		IMR(MST_SLVERR)		|	\
+	)
+
+#define XILINX_PCIE_DMA_IMR_ALL_MASK	0x0ff30fe9
+#define XILINX_PCIE_DMA_IDR_ALL_MASK	0xffffffff
+#define XILINX_PCIE_DMA_IDRN_MASK	GENMASK(19, 16)
+
+/* Root Port Error Register definitions */
+#define XILINX_PCIE_DMA_RPEFR_ERR_VALID	BIT(18)
+#define XILINX_PCIE_DMA_RPEFR_REQ_ID	GENMASK(15, 0)
+#define XILINX_PCIE_DMA_RPEFR_ALL_MASK	0xffffffff
+
+/* Root Port Interrupt Register definitions */
+#define XILINX_PCIE_DMA_IDRN_SHIFT	16
+
+/* Root Port Status/control Register definitions */
+#define XILINX_PCIE_DMA_REG_RPSC_BEN	BIT(0)
+
+/* Phy Status/Control Register definitions */
+#define XILINX_PCIE_DMA_REG_PSCR_LNKUP	BIT(11)
+
+/* Number of MSI IRQs */
+#define XILINX_NUM_MSI_IRQS	64
+
+struct xilinx_msi {
+	struct irq_domain	*msi_domain;
+	unsigned long		*bitmap;
+	struct irq_domain	*dev_domain;
+	struct mutex		lock;		/* protect bitmap variable */
+	int			irq_msi0;
+	int			irq_msi1;
+};
+
+/**
+ * struct pl_dma_pcie - PCIe port information
+ * @dev: Device pointer
+ * @reg_base: IO Mapped Register Base
+ * @irq: Interrupt number
+ * @cfg: Holds mappings of config space window
+ * @phys_reg_base: Physical address of reg base
+ * @intx_domain: Legacy IRQ domain pointer
+ * @pldma_domain: PL DMA IRQ domain pointer
+ * @resources: Bus Resources
+ * @msi: MSI information
+ * @intx_irq: INTx error interrupt number
+ * @lock: Lock protecting shared register access
+ */
+struct pl_dma_pcie {
+	struct device			*dev;
+	void __iomem			*reg_base;
+	int				irq;
+	struct pci_config_window	*cfg;
+	phys_addr_t			phys_reg_base;
+	struct irq_domain		*intx_domain;
+	struct irq_domain		*pldma_domain;
+	struct list_head		resources;
+	struct xilinx_msi		msi;
+	int				intx_irq;
+	raw_spinlock_t			lock;
+};
+
+static inline u32 pcie_read(struct pl_dma_pcie *port, u32 reg)
+{
+	return readl(port->reg_base + reg);
+}
+
+static inline void pcie_write(struct pl_dma_pcie *port, u32 val, u32 reg)
+{
+	writel(val, port->reg_base + reg);
+}
+
+static inline bool xilinx_pl_dma_pcie_link_up(struct pl_dma_pcie *port)
+{
+	return (pcie_read(port, XILINX_PCIE_DMA_REG_PSCR) &
+		XILINX_PCIE_DMA_REG_PSCR_LNKUP) ? true : false;
+}
+
+static void xilinx_pl_dma_pcie_clear_err_interrupts(struct pl_dma_pcie *port)
+{
+	unsigned long val = pcie_read(port, XILINX_PCIE_DMA_REG_RPEFR);
+
+	if (val & XILINX_PCIE_DMA_RPEFR_ERR_VALID) {
+		dev_dbg(port->dev, "Requester ID %lu\n",
+			val & XILINX_PCIE_DMA_RPEFR_REQ_ID);
+		pcie_write(port, XILINX_PCIE_DMA_RPEFR_ALL_MASK,
+			   XILINX_PCIE_DMA_REG_RPEFR);
+	}
+}
+
+static bool xilinx_pl_dma_pcie_valid_device(struct pci_bus *bus,
+					    unsigned int devfn)
+{
+	struct pl_dma_pcie *port = bus->sysdata;
+
+	if (!pci_is_root_bus(bus)) {
+		/* Checking whether the link is up is the last line of
+		 * defense, and this check is inherently racy by definition.
+		 * Sending a PIO request to a downstream device when the link is
+		 * down causes an unrecoverable error, and a reset of the entire
+		 * PCIe controller will be needed. We can reduce the likelihood
+		 * of that unrecoverable error by checking whether the link is
+		 * up, but we can't completely prevent it because the link may
+		 * go down between the link-up check and the PIO request.
+		 */
+		if (!xilinx_pl_dma_pcie_link_up(port))
+			return false;
+	} else if (devfn > 0)
+		/* Only one device down on each root port */
+		return false;
+
+	return true;
+}
+
+static void __iomem *xilinx_pl_dma_pcie_map_bus(struct pci_bus *bus,
+						unsigned int devfn, int where)
+{
+	struct pl_dma_pcie *port = bus->sysdata;
+
+	if (!xilinx_pl_dma_pcie_valid_device(bus, devfn))
+		return NULL;
+
+	return port->reg_base + PCIE_ECAM_OFFSET(bus->number, devfn, where);
+}
+
+/* PCIe operations */
+static struct pci_ecam_ops xilinx_pl_dma_pcie_ops = {
+	.pci_ops = {
+		.map_bus = xilinx_pl_dma_pcie_map_bus,
+		.read	= pci_generic_config_read,
+		.write	= pci_generic_config_write,
+	}
+};
+
+static void xilinx_pl_dma_pcie_enable_msi(struct pl_dma_pcie *port)
+{
+	phys_addr_t msi_addr = port->phys_reg_base;
+
+	pcie_write(port, upper_32_bits(msi_addr), XILINX_PCIE_DMA_REG_MSIBASE1);
+	pcie_write(port, lower_32_bits(msi_addr), XILINX_PCIE_DMA_REG_MSIBASE2);
+}
+
+static void xilinx_mask_intx_irq(struct irq_data *data)
+{
+	struct pl_dma_pcie *port = irq_data_get_irq_chip_data(data);
+	unsigned long flags;
+	u32 mask, val;
+
+	mask = BIT(data->hwirq + XILINX_PCIE_DMA_IDRN_SHIFT);
+	raw_spin_lock_irqsave(&port->lock, flags);
+	val = pcie_read(port, XILINX_PCIE_DMA_REG_IDRN_MASK);
+	pcie_write(port, (val & (~mask)), XILINX_PCIE_DMA_REG_IDRN_MASK);
+	raw_spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void xilinx_unmask_intx_irq(struct irq_data *data)
+{
+	struct pl_dma_pcie *port = irq_data_get_irq_chip_data(data);
+	unsigned long flags;
+	u32 mask, val;
+
+	mask = BIT(data->hwirq + XILINX_PCIE_DMA_IDRN_SHIFT);
+	raw_spin_lock_irqsave(&port->lock, flags);
+	val = pcie_read(port, XILINX_PCIE_DMA_REG_IDRN_MASK);
+	pcie_write(port, (val | mask), XILINX_PCIE_DMA_REG_IDRN_MASK);
+	raw_spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static struct irq_chip xilinx_leg_irq_chip = {
+	.name		= "pl_dma:INTx",
+	.irq_mask	= xilinx_mask_intx_irq,
+	.irq_unmask	= xilinx_unmask_intx_irq,
+};
+
+static int xilinx_pl_dma_pcie_intx_map(struct irq_domain *domain,
+				       unsigned int irq, irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &xilinx_leg_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	irq_set_status_flags(irq, IRQ_LEVEL);
+
+	return 0;
+}
+
+/* INTx IRQ Domain operations */
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = xilinx_pl_dma_pcie_intx_map,
+};
+
+static irqreturn_t xilinx_pl_dma_pcie_msi_handler_high(int irq, void *args)
+{
+	struct xilinx_msi *msi;
+	unsigned long status;
+	u32 bit, virq;
+	struct pl_dma_pcie *port = args;
+
+	msi = &port->msi;
+
+	while ((status = pcie_read(port, XILINX_PCIE_DMA_REG_MSI_HI)) != 0) {
+		for_each_set_bit(bit, &status, 32) {
+			pcie_write(port, 1 << bit, XILINX_PCIE_DMA_REG_MSI_HI);
+			bit = bit + 32;
+			virq = irq_find_mapping(msi->dev_domain, bit);
+			if (virq)
+				generic_handle_irq(virq);
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xilinx_pl_dma_pcie_msi_handler_low(int irq, void *args)
+{
+	struct pl_dma_pcie *port = args;
+	struct xilinx_msi *msi;
+	unsigned long status;
+	u32 bit, virq;
+
+	msi = &port->msi;
+
+	while ((status = pcie_read(port, XILINX_PCIE_DMA_REG_MSI_LOW)) != 0) {
+		for_each_set_bit(bit, &status, 32) {
+			pcie_write(port, 1 << bit, XILINX_PCIE_DMA_REG_MSI_LOW);
+			virq = irq_find_mapping(msi->dev_domain, bit);
+			if (virq)
+				generic_handle_irq(virq);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xilinx_pl_dma_pcie_event_flow(int irq, void *args)
+{
+	struct pl_dma_pcie *port = args;
+	unsigned long val;
+	int i;
+
+	val = pcie_read(port, XILINX_PCIE_DMA_REG_IDR);
+	val &= pcie_read(port, XILINX_PCIE_DMA_REG_IMR);
+	for_each_set_bit(i, &val, 32)
+		generic_handle_domain_irq(port->pldma_domain, i);
+
+	pcie_write(port, val, XILINX_PCIE_DMA_REG_IDR);
+
+	return IRQ_HANDLED;
+}
+
+#define _IC(x, s)                              \
+	[XILINX_PCIE_INTR_ ## x] = { __stringify(x), s }
+
+static const struct {
+	const char	*sym;
+	const char	*str;
+} intr_cause[32] = {
+	_IC(LINK_DOWN,		"Link Down"),
+	_IC(HOT_RESET,		"Hot reset"),
+	_IC(CFG_TIMEOUT,	"ECAM access timeout"),
+	_IC(CORRECTABLE,	"Correctable error message"),
+	_IC(NONFATAL,		"Non fatal error message"),
+	_IC(FATAL,		"Fatal error message"),
+	_IC(SLV_UNSUPP,		"Slave unsupported request"),
+	_IC(SLV_UNEXP,		"Slave unexpected completion"),
+	_IC(SLV_COMPL,		"Slave completion timeout"),
+	_IC(SLV_ERRP,		"Slave Error Poison"),
+	_IC(SLV_CMPABT,		"Slave Completer Abort"),
+	_IC(SLV_ILLBUR,		"Slave Illegal Burst"),
+	_IC(MST_DECERR,		"Master decode error"),
+	_IC(MST_SLVERR,		"Master slave error"),
+};
+
+static irqreturn_t xilinx_pl_dma_pcie_intr_handler(int irq, void *dev_id)
+{
+	struct pl_dma_pcie *port = (struct pl_dma_pcie *)dev_id;
+	struct device *dev = port->dev;
+	struct irq_data *d;
+
+	d = irq_domain_get_irq_data(port->pldma_domain, irq);
+	switch (d->hwirq) {
+	case XILINX_PCIE_INTR_CORRECTABLE:
+	case XILINX_PCIE_INTR_NONFATAL:
+	case XILINX_PCIE_INTR_FATAL:
+		xilinx_pl_dma_pcie_clear_err_interrupts(port);
+		fallthrough;
+
+	default:
+		if (intr_cause[d->hwirq].str)
+			dev_warn(dev, "%s\n", intr_cause[d->hwirq].str);
+		else
+			dev_warn(dev, "Unknown IRQ %ld\n", d->hwirq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct irq_chip xilinx_msi_irq_chip = {
+	.name = "pl_dma:PCIe MSI",
+	.irq_enable = pci_msi_unmask_irq,
+	.irq_disable = pci_msi_mask_irq,
+	.irq_mask = pci_msi_mask_irq,
+	.irq_unmask = pci_msi_unmask_irq,
+};
+
+static struct msi_domain_info xilinx_msi_domain_info = {
+	.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+		MSI_FLAG_MULTI_PCI_MSI),
+	.chip = &xilinx_msi_irq_chip,
+};
+
+static void xilinx_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct pl_dma_pcie *pcie = irq_data_get_irq_chip_data(data);
+	phys_addr_t msi_addr = pcie->phys_reg_base;
+
+	msg->address_lo = lower_32_bits(msi_addr);
+	msg->address_hi = upper_32_bits(msi_addr);
+	msg->data = data->hwirq;
+}
+
+static int xilinx_msi_set_affinity(struct irq_data *irq_data,
+				   const struct cpumask *mask, bool force)
+{
+	return -EINVAL;
+}
+
+static struct irq_chip xilinx_irq_chip = {
+	.name = "pl_dma:MSI",
+	.irq_compose_msi_msg = xilinx_compose_msi_msg,
+	.irq_set_affinity = xilinx_msi_set_affinity,
+};
+
+static int xilinx_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				   unsigned int nr_irqs, void *args)
+{
+	struct pl_dma_pcie *pcie = domain->host_data;
+	struct xilinx_msi *msi = &pcie->msi;
+	int bit, i;
+
+	mutex_lock(&msi->lock);
+	bit = bitmap_find_free_region(msi->bitmap, XILINX_NUM_MSI_IRQS,
+				      get_count_order(nr_irqs));
+	if (bit < 0) {
+		mutex_unlock(&msi->lock);
+		return -ENOSPC;
+	}
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_domain_set_info(domain, virq + i, bit + i, &xilinx_irq_chip,
+				    domain->host_data, handle_simple_irq,
+				    NULL, NULL);
+	}
+	mutex_unlock(&msi->lock);
+	return 0;
+}
+
+static void xilinx_irq_domain_free(struct irq_domain *domain, unsigned int virq,
+				   unsigned int nr_irqs)
+{
+	struct irq_data *data = irq_domain_get_irq_data(domain, virq);
+	struct pl_dma_pcie *pcie = irq_data_get_irq_chip_data(data);
+	struct xilinx_msi *msi = &pcie->msi;
+
+	mutex_lock(&msi->lock);
+	bitmap_release_region(msi->bitmap, data->hwirq,
+			      get_count_order(nr_irqs));
+	mutex_unlock(&msi->lock);
+}
+
+static const struct irq_domain_ops dev_msi_domain_ops = {
+	.alloc	= xilinx_irq_domain_alloc,
+	.free	= xilinx_irq_domain_free,
+};
+
+static void xilinx_pl_dma_pcie_free_irq_domains(struct pl_dma_pcie *port)
+{
+	struct xilinx_msi *msi = &port->msi;
+
+	if (port->intx_domain) {
+		irq_domain_remove(port->intx_domain);
+		port->intx_domain = NULL;
+	}
+
+	if (msi->dev_domain) {
+		irq_domain_remove(msi->dev_domain);
+		msi->dev_domain = NULL;
+	}
+
+	if (msi->msi_domain) {
+		irq_domain_remove(msi->msi_domain);
+		msi->msi_domain = NULL;
+	}
+}
+
+static int xilinx_pl_dma_pcie_init_msi_irq_domain(struct pl_dma_pcie *port)
+{
+	struct device *dev = port->dev;
+	struct xilinx_msi *msi = &port->msi;
+	int size = BITS_TO_LONGS(XILINX_NUM_MSI_IRQS) * sizeof(long);
+	struct fwnode_handle *fwnode = of_node_to_fwnode(port->dev->of_node);
+
+	msi->dev_domain = irq_domain_add_linear(NULL, XILINX_NUM_MSI_IRQS,
+						&dev_msi_domain_ops, port);
+	if (!msi->dev_domain)
+		goto out;
+
+	msi->msi_domain = pci_msi_create_irq_domain(fwnode,
+						    &xilinx_msi_domain_info,
+						    msi->dev_domain);
+	if (!msi->msi_domain)
+		goto out;
+
+	mutex_init(&msi->lock);
+	msi->bitmap = kzalloc(size, GFP_KERNEL);
+	if (!msi->bitmap)
+		goto out;
+
+	raw_spin_lock_init(&port->lock);
+	xilinx_pl_dma_pcie_enable_msi(port);
+
+	return 0;
+
+out:
+	xilinx_pl_dma_pcie_free_irq_domains(port);
+	dev_err(dev, "Failed to allocate MSI IRQ domains\n");
+	return -ENOMEM;
+}
+
+/* INTx error interrupts are Xilinx controller specific interrupt, used to
+ * notify user about errors such as cfg timeout, slave unsupported requests,
+ * fatal and non fatal error etc.
+ */
+
+static irqreturn_t xilinx_pl_dma_pcie_intx_flow(int irq, void *args)
+{
+	unsigned long val;
+	int i;
+	struct pl_dma_pcie *port = args;
+
+	val = FIELD_GET(XILINX_PCIE_DMA_IDRN_MASK,
+			pcie_read(port, XILINX_PCIE_DMA_REG_IDRN));
+
+	for_each_set_bit(i, &val, PCI_NUM_INTX)
+		generic_handle_domain_irq(port->intx_domain, i);
+	return IRQ_HANDLED;
+}
+
+static void xilinx_pl_dma_pcie_mask_event_irq(struct irq_data *d)
+{
+	struct pl_dma_pcie *port = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	raw_spin_lock(&port->lock);
+	val = pcie_read(port, XILINX_PCIE_DMA_REG_IMR);
+	val &= ~BIT(d->hwirq);
+	pcie_write(port, val, XILINX_PCIE_DMA_REG_IMR);
+	raw_spin_unlock(&port->lock);
+}
+
+static void xilinx_pl_dma_pcie_unmask_event_irq(struct irq_data *d)
+{
+	struct pl_dma_pcie *port = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	raw_spin_lock(&port->lock);
+	val = pcie_read(port, XILINX_PCIE_DMA_REG_IMR);
+	val |= BIT(d->hwirq);
+	pcie_write(port, val, XILINX_PCIE_DMA_REG_IMR);
+	raw_spin_unlock(&port->lock);
+}
+
+static struct irq_chip xilinx_pl_dma_pcie_event_irq_chip = {
+	.name		= "pl_dma:RC-Event",
+	.irq_mask	= xilinx_pl_dma_pcie_mask_event_irq,
+	.irq_unmask	= xilinx_pl_dma_pcie_unmask_event_irq,
+};
+
+static int xilinx_pl_dma_pcie_event_map(struct irq_domain *domain,
+					unsigned int irq, irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &xilinx_pl_dma_pcie_event_irq_chip,
+				 handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+	irq_set_status_flags(irq, IRQ_LEVEL);
+
+	return 0;
+}
+
+static const struct irq_domain_ops event_domain_ops = {
+	.map = xilinx_pl_dma_pcie_event_map,
+};
+
+/**
+ * xilinx_pl_dma_pcie_init_irq_domain - Initialize IRQ domain
+ * @port: PCIe port information
+ *
+ * Return: '0' on success and error value on failure
+ */
+static int xilinx_pl_dma_pcie_init_irq_domain(struct pl_dma_pcie *port)
+{
+	struct device *dev = port->dev;
+	struct device_node *node = dev->of_node;
+	struct device_node *pcie_intc_node;
+	int ret;
+
+	/* Setup INTx */
+	pcie_intc_node = of_get_child_by_name(node, "interrupt-controller");
+	if (!pcie_intc_node) {
+		dev_err(dev, "No PCIe Intc node found\n");
+		return -EINVAL;
+	}
+
+	port->pldma_domain = irq_domain_add_linear(pcie_intc_node, 32,
+						   &event_domain_ops, port);
+	if (!port->pldma_domain)
+		return -ENOMEM;
+
+	irq_domain_update_bus_token(port->pldma_domain, DOMAIN_BUS_NEXUS);
+
+	port->intx_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX,
+						  &intx_domain_ops, port);
+	if (!port->intx_domain) {
+		dev_err(dev, "Failed to get a INTx IRQ domain\n");
+		return PTR_ERR(port->intx_domain);
+	}
+
+	irq_domain_update_bus_token(port->intx_domain, DOMAIN_BUS_WIRED);
+
+	ret = xilinx_pl_dma_pcie_init_msi_irq_domain(port);
+	if (ret != 0) {
+		irq_domain_remove(port->intx_domain);
+		return -ENOMEM;
+	}
+
+	of_node_put(pcie_intc_node);
+	raw_spin_lock_init(&port->lock);
+
+	return 0;
+}
+
+static int xilinx_pl_dma_pcie_setup_irq(struct pl_dma_pcie *port)
+{
+	struct device *dev = port->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	int i, irq, err;
+
+	port->irq = platform_get_irq(pdev, 0);
+	if (port->irq < 0)
+		return port->irq;
+
+	for (i = 0; i < ARRAY_SIZE(intr_cause); i++) {
+		int err;
+
+		if (!intr_cause[i].str)
+			continue;
+
+		irq = irq_create_mapping(port->pldma_domain, i);
+		if (!irq) {
+			dev_err(dev, "Failed to map interrupt\n");
+			return -ENXIO;
+		}
+
+		err = devm_request_irq(dev, irq,
+				       xilinx_pl_dma_pcie_intr_handler,
+				       IRQF_SHARED | IRQF_NO_THREAD,
+				       intr_cause[i].sym, port);
+		if (err) {
+			dev_err(dev, "Failed to request IRQ %d\n", irq);
+			return err;
+		}
+	}
+
+	port->intx_irq = irq_create_mapping(port->pldma_domain,
+					    XILINX_PCIE_INTR_INTX);
+	if (!port->intx_irq) {
+		dev_err(dev, "Failed to map INTx interrupt\n");
+		return -ENXIO;
+	}
+
+	err = devm_request_irq(dev, port->intx_irq, xilinx_pl_dma_pcie_intx_flow,
+			       IRQF_SHARED | IRQF_NO_THREAD, NULL, port);
+	if (err) {
+		dev_err(dev, "Failed to request INTx IRQ %d\n", irq);
+		return err;
+	}
+	err = devm_request_irq(dev, port->irq, xilinx_pl_dma_pcie_event_flow,
+			       IRQF_SHARED | IRQF_NO_THREAD, NULL, port);
+	if (err) {
+		dev_err(dev, "Failed to request event IRQ %d\n", irq);
+		return err;
+	}
+	return 0;
+}
+
+static void xilinx_pl_dma_pcie_init_port(struct pl_dma_pcie *port)
+{
+	if (xilinx_pl_dma_pcie_link_up(port))
+		dev_info(port->dev, "PCIe Link is UP\n");
+	else
+		dev_info(port->dev, "PCIe Link is DOWN\n");
+
+	/* Disable all interrupts */
+	pcie_write(port, ~XILINX_PCIE_DMA_IDR_ALL_MASK,
+		   XILINX_PCIE_DMA_REG_IMR);
+
+	/* Clear pending interrupts */
+	pcie_write(port, pcie_read(port, XILINX_PCIE_DMA_REG_IDR) &
+			 XILINX_PCIE_DMA_IMR_ALL_MASK,
+		   XILINX_PCIE_DMA_REG_IDR);
+
+	/* Needed for MSI DECODE MODE */
+	pcie_write(port, XILINX_PCIE_DMA_IDR_ALL_MASK,
+		   XILINX_PCIE_DMA_REG_MSI_LOW_MASK);
+	pcie_write(port, XILINX_PCIE_DMA_IDR_ALL_MASK,
+		   XILINX_PCIE_DMA_REG_MSI_HI_MASK);
+
+	/* Set the Bridge enable bit */
+	pcie_write(port, pcie_read(port, XILINX_PCIE_DMA_REG_RPSC) |
+			 XILINX_PCIE_DMA_REG_RPSC_BEN,
+		   XILINX_PCIE_DMA_REG_RPSC);
+}
+
+static int xilinx_request_msi_irq(struct pl_dma_pcie *port)
+{
+	struct device *dev = port->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	int ret;
+
+	port->msi.irq_msi0 = platform_get_irq_byname(pdev, "msi0");
+	if (port->msi.irq_msi0 <= 0) {
+		dev_err(dev, "Unable to find msi0 IRQ line\n");
+		return port->msi.irq_msi0;
+	}
+	ret = devm_request_irq(dev, port->msi.irq_msi0, xilinx_pl_dma_pcie_msi_handler_low,
+			       IRQF_SHARED | IRQF_NO_THREAD, "xlnx-pcie-dma-pl",
+			       port);
+	if (ret) {
+		dev_err(dev, "Failed to register interrupt\n");
+		return ret;
+		}
+	port->msi.irq_msi1 = platform_get_irq_byname(pdev, "msi1");
+	if (port->msi.irq_msi1 <= 0) {
+		dev_err(dev, "Unable to find msi1 IRQ line\n");
+		return port->msi.irq_msi1;
+	}
+	ret = devm_request_irq(dev, port->msi.irq_msi1, xilinx_pl_dma_pcie_msi_handler_high,
+			       IRQF_SHARED | IRQF_NO_THREAD, "xlnx-pcie-dma-pl",
+			       port);
+	if (ret) {
+		dev_err(dev, "Failed to register interrupt\n");
+		return ret;
+		}
+	return 0;
+}
+
+static int xilinx_pl_dma_pcie_parse_dt(struct pl_dma_pcie *port,
+				       struct resource *bus_range)
+{
+	struct device *dev = port->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct resource *res;
+	int err;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Missing \"reg\" property\n");
+		return -ENXIO;
+	}
+	port->phys_reg_base = res->start;
+
+	port->cfg = pci_ecam_create(dev, res, bus_range, &xilinx_pl_dma_pcie_ops);
+	if (IS_ERR(port->cfg))
+		return PTR_ERR(port->cfg);
+
+	port->reg_base = port->cfg->win;
+
+	err = xilinx_request_msi_irq(port);
+	if (err) {
+		pci_ecam_free(port->cfg);
+		return err;
+	}
+
+	return 0;
+}
+
+static int xilinx_pl_dma_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pl_dma_pcie *port;
+	struct pci_host_bridge *bridge;
+	struct resource_entry *bus;
+	int err;
+
+	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*port));
+	if (!bridge)
+		return -ENODEV;
+
+	port = pci_host_bridge_priv(bridge);
+
+	port->dev = dev;
+
+	bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
+	if (!bus)
+		return -ENODEV;
+
+	err = xilinx_pl_dma_pcie_parse_dt(port, bus->res);
+	if (err) {
+		dev_err(dev, "Parsing DT failed\n");
+		return err;
+	}
+
+	xilinx_pl_dma_pcie_init_port(port);
+
+	err = xilinx_pl_dma_pcie_init_irq_domain(port);
+	if (err)
+		goto err_irq_domain;
+
+	err = xilinx_pl_dma_pcie_setup_irq(port);
+
+	bridge->sysdata = port;
+	bridge->ops = &xilinx_pl_dma_pcie_ops.pci_ops;
+
+	err = pci_host_probe(bridge);
+	if (err < 0)
+		goto err_host_bridge;
+
+	return 0;
+
+err_host_bridge:
+	xilinx_pl_dma_pcie_free_irq_domains(port);
+
+err_irq_domain:
+	pci_ecam_free(port->cfg);
+	return err;
+}
+
+static const struct of_device_id xilinx_pl_dma_pcie_of_match[] = {
+	{
+		.compatible = "xlnx,xdma-host-3.00",
+	},
+	{}
+};
+
+static struct platform_driver xilinx_pl_dma_pcie_driver = {
+	.driver = {
+		.name = "xilinx-xdma-pcie",
+		.of_match_table = xilinx_pl_dma_pcie_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = xilinx_pl_dma_pcie_probe,
+};
+
+builtin_platform_driver(xilinx_pl_dma_pcie_driver);
-- 
2.25.1