Merge branch 'pci/ntb'

- Account for 64-bit BARs in pci_epc_get_first_free_bar() (Kishon Vijay
  Abraham I)

- Add pci_epc_get_next_free_bar() helper (Kishon Vijay Abraham I)

- Return error codes on failure of endpoint BAR interfaces (Kishon Vijay
  Abraham I)

- Remove unused pci_epf_match_device() (Kishon Vijay Abraham I)

- Add support for secondary endpoint controller to prepare for NTB endpoint
  functionality (Kishon Vijay Abraham I)

- Add configfs support for secondary endpoint controller (Kishon Vijay
  Abraham I)

- Add MSI address mapping ops for NTB doorbell support (Kishon Vijay
  Abraham I)

- Add ops for endpoint function-specific attributes (Kishon Vijay Abraham
  I)

- Allow configfs subdirectory for endpoint function configuration (Kishon
  Vijay Abraham I)

- Implement cadence MSI address mapping ops (Kishon Vijay Abraham I)

- Configure cadence LM_EP_FUNC_CFG based on epc->function_num_map (Kishon
  Vijay Abraham I)

- Add endpoint-side driver to provide NTB functionality (Kishon Vijay
  Abraham I)

- Add host-side driver for generic EPF NTB functionality (Kishon Vijay
  Abraham I)

- Document NTB endpoint functionality (Kishon Vijay Abraham I)

* pci/ntb:
  Documentation: PCI: Add PCI endpoint NTB function user guide
  Documentation: PCI: Add configfs binding documentation for pci-ntb endpoint function
  NTB: Add support for EPF PCI Non-Transparent Bridge
  PCI: Add TI J721E device to PCI IDs
  PCI: endpoint: Add EP function driver to provide NTB functionality
  PCI: cadence: Configure LM_EP_FUNC_CFG based on epc->function_num_map
  PCI: cadence: Implement ->msi_map_irq() ops
  PCI: endpoint: Allow user to create sub-directory of 'EPF Device' directory
  PCI: endpoint: Add pci_epf_ops to expose function-specific attrs
  PCI: endpoint: Add pci_epc_ops to map MSI IRQ
  PCI: endpoint: Add support in configfs to associate two EPCs with EPF
  PCI: endpoint: Add support to associate secondary EPC with EPF
  PCI: endpoint: Remove unused pci_epf_match_device()
  PCI: endpoint: Make *_free_bar() to return error codes on failure
  PCI: endpoint: Add helper API to get the 'next' unreserved BAR
  PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR
  Documentation: PCI: Add specification for the PCI NTB function device

14 files changed, 3324 insertions, 65 deletions

diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
index eff481ce08ee..1b2868ca4f2a 100644
--- a/drivers/misc/pci_endpoint_test.c
+++ b/drivers/misc/pci_endpoint_test.c
@@ -68,7 +68,6 @@
 #define PCI_ENDPOINT_TEST_FLAGS			0x2c
 #define FLAG_USE_DMA				BIT(0)
 
-#define PCI_DEVICE_ID_TI_J721E			0xb00d
 #define PCI_DEVICE_ID_TI_AM654			0xb00c
 #define PCI_DEVICE_ID_LS1088A			0x80c0
 
diff --git a/drivers/ntb/hw/Kconfig b/drivers/ntb/hw/Kconfig
index e77c587060ff..c325be526b80 100644
--- a/drivers/ntb/hw/Kconfig
+++ b/drivers/ntb/hw/Kconfig
@@ -2,4 +2,5 @@
 source "drivers/ntb/hw/amd/Kconfig"
 source "drivers/ntb/hw/idt/Kconfig"
 source "drivers/ntb/hw/intel/Kconfig"
+source "drivers/ntb/hw/epf/Kconfig"
 source "drivers/ntb/hw/mscc/Kconfig"
diff --git a/drivers/ntb/hw/Makefile b/drivers/ntb/hw/Makefile
index 4714d6238845..223ca592b5f9 100644
--- a/drivers/ntb/hw/Makefile
+++ b/drivers/ntb/hw/Makefile
@@ -2,4 +2,5 @@
 obj-$(CONFIG_NTB_AMD)	+= amd/
 obj-$(CONFIG_NTB_IDT)	+= idt/
 obj-$(CONFIG_NTB_INTEL)	+= intel/
+obj-$(CONFIG_NTB_EPF)	+= epf/
 obj-$(CONFIG_NTB_SWITCHTEC) += mscc/
diff --git a/drivers/ntb/hw/epf/Kconfig b/drivers/ntb/hw/epf/Kconfig
new file mode 100644
index 000000000000..6197d1aab344
--- /dev/null
+++ b/drivers/ntb/hw/epf/Kconfig
@@ -0,0 +1,6 @@
+config NTB_EPF
+	tristate "Generic EPF Non-Transparent Bridge support"
+	depends on m
+	help
+	  This driver supports EPF NTB on configurable endpoint.
+	  If unsure, say N.
diff --git a/drivers/ntb/hw/epf/Makefile b/drivers/ntb/hw/epf/Makefile
new file mode 100644
index 000000000000..2f560a422bc6
--- /dev/null
+++ b/drivers/ntb/hw/epf/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_NTB_EPF) += ntb_hw_epf.o
diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
new file mode 100644
index 000000000000..b019755e4e21
--- /dev/null
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -0,0 +1,753 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Host side endpoint driver to implement Non-Transparent Bridge functionality
+ *
+ * Copyright (C) 2020 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/ntb.h>
+
+#define NTB_EPF_COMMAND		0x0
+#define CMD_CONFIGURE_DOORBELL	1
+#define CMD_TEARDOWN_DOORBELL	2
+#define CMD_CONFIGURE_MW	3
+#define CMD_TEARDOWN_MW		4
+#define CMD_LINK_UP		5
+#define CMD_LINK_DOWN		6
+
+#define NTB_EPF_ARGUMENT	0x4
+#define MSIX_ENABLE		BIT(16)
+
+#define NTB_EPF_CMD_STATUS	0x8
+#define COMMAND_STATUS_OK	1
+#define COMMAND_STATUS_ERROR	2
+
+#define NTB_EPF_LINK_STATUS	0x0A
+#define LINK_STATUS_UP		BIT(0)
+
+#define NTB_EPF_TOPOLOGY	0x0C
+#define NTB_EPF_LOWER_ADDR	0x10
+#define NTB_EPF_UPPER_ADDR	0x14
+#define NTB_EPF_LOWER_SIZE	0x18
+#define NTB_EPF_UPPER_SIZE	0x1C
+#define NTB_EPF_MW_COUNT	0x20
+#define NTB_EPF_MW1_OFFSET	0x24
+#define NTB_EPF_SPAD_OFFSET	0x28
+#define NTB_EPF_SPAD_COUNT	0x2C
+#define NTB_EPF_DB_ENTRY_SIZE	0x30
+#define NTB_EPF_DB_DATA(n)	(0x34 + (n) * 4)
+#define NTB_EPF_DB_OFFSET(n)	(0xB4 + (n) * 4)
+
+#define NTB_EPF_MIN_DB_COUNT	3
+#define NTB_EPF_MAX_DB_COUNT	31
+#define NTB_EPF_MW_OFFSET	2
+
+#define NTB_EPF_COMMAND_TIMEOUT	1000 /* 1 Sec */
+
+enum pci_barno {
+	BAR_0,
+	BAR_1,
+	BAR_2,
+	BAR_3,
+	BAR_4,
+	BAR_5,
+};
+
+struct ntb_epf_dev {
+	struct ntb_dev ntb;
+	struct device *dev;
+	/* Mutex to protect providing commands to NTB EPF */
+	struct mutex cmd_lock;
+
+	enum pci_barno ctrl_reg_bar;
+	enum pci_barno peer_spad_reg_bar;
+	enum pci_barno db_reg_bar;
+
+	unsigned int mw_count;
+	unsigned int spad_count;
+	unsigned int db_count;
+
+	void __iomem *ctrl_reg;
+	void __iomem *db_reg;
+	void __iomem *peer_spad_reg;
+
+	unsigned int self_spad;
+	unsigned int peer_spad;
+
+	int db_val;
+	u64 db_valid_mask;
+};
+
+#define ntb_ndev(__ntb) container_of(__ntb, struct ntb_epf_dev, ntb)
+
+struct ntb_epf_data {
+	/* BAR that contains both control region and self spad region */
+	enum pci_barno ctrl_reg_bar;
+	/* BAR that contains peer spad region */
+	enum pci_barno peer_spad_reg_bar;
+	/* BAR that contains Doorbell region and Memory window '1' */
+	enum pci_barno db_reg_bar;
+};
+
+static int ntb_epf_send_command(struct ntb_epf_dev *ndev, u32 command,
+				u32 argument)
+{
+	ktime_t timeout;
+	bool timedout;
+	int ret = 0;
+	u32 status;
+
+	mutex_lock(&ndev->cmd_lock);
+	writel(argument, ndev->ctrl_reg + NTB_EPF_ARGUMENT);
+	writel(command, ndev->ctrl_reg + NTB_EPF_COMMAND);
+
+	timeout = ktime_add_ms(ktime_get(), NTB_EPF_COMMAND_TIMEOUT);
+	while (1) {
+		timedout = ktime_after(ktime_get(), timeout);
+		status = readw(ndev->ctrl_reg + NTB_EPF_CMD_STATUS);
+
+		if (status == COMMAND_STATUS_ERROR) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (status == COMMAND_STATUS_OK)
+			break;
+
+		if (WARN_ON(timedout)) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+
+		usleep_range(5, 10);
+	}
+
+	writew(0, ndev->ctrl_reg + NTB_EPF_CMD_STATUS);
+	mutex_unlock(&ndev->cmd_lock);
+
+	return ret;
+}
+
+static int ntb_epf_mw_to_bar(struct ntb_epf_dev *ndev, int idx)
+{
+	struct device *dev = ndev->dev;
+
+	if (idx < 0 || idx > ndev->mw_count) {
+		dev_err(dev, "Unsupported Memory Window index %d\n", idx);
+		return -EINVAL;
+	}
+
+	return idx + 2;
+}
+
+static int ntb_epf_mw_count(struct ntb_dev *ntb, int pidx)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+
+	if (pidx != NTB_DEF_PEER_IDX) {
+		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
+		return -EINVAL;
+	}
+
+	return ndev->mw_count;
+}
+
+static int ntb_epf_mw_get_align(struct ntb_dev *ntb, int pidx, int idx,
+				resource_size_t *addr_align,
+				resource_size_t *size_align,
+				resource_size_t *size_max)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	int bar;
+
+	if (pidx != NTB_DEF_PEER_IDX) {
+		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
+		return -EINVAL;
+	}
+
+	bar = ntb_epf_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	if (addr_align)
+		*addr_align = SZ_4K;
+
+	if (size_align)
+		*size_align = 1;
+
+	if (size_max)
+		*size_max = pci_resource_len(ndev->ntb.pdev, bar);
+
+	return 0;
+}
+
+static u64 ntb_epf_link_is_up(struct ntb_dev *ntb,
+			      enum ntb_speed *speed,
+			      enum ntb_width *width)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	u32 status;
+
+	status = readw(ndev->ctrl_reg + NTB_EPF_LINK_STATUS);
+
+	return status & LINK_STATUS_UP;
+}
+
+static u32 ntb_epf_spad_read(struct ntb_dev *ntb, int idx)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count) {
+		dev_err(dev, "READ: Invalid ScratchPad Index %d\n", idx);
+		return 0;
+	}
+
+	offset = readl(ndev->ctrl_reg + NTB_EPF_SPAD_OFFSET);
+	offset += (idx << 2);
+
+	return readl(ndev->ctrl_reg + offset);
+}
+
+static int ntb_epf_spad_write(struct ntb_dev *ntb,
+			      int idx, u32 val)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count) {
+		dev_err(dev, "WRITE: Invalid ScratchPad Index %d\n", idx);
+		return -EINVAL;
+	}
+
+	offset = readl(ndev->ctrl_reg + NTB_EPF_SPAD_OFFSET);
+	offset += (idx << 2);
+	writel(val, ndev->ctrl_reg + offset);
+
+	return 0;
+}
+
+static u32 ntb_epf_peer_spad_read(struct ntb_dev *ntb, int pidx, int idx)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	u32 offset;
+
+	if (pidx != NTB_DEF_PEER_IDX) {
+		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
+		return -EINVAL;
+	}
+
+	if (idx < 0 || idx >= ndev->spad_count) {
+		dev_err(dev, "WRITE: Invalid Peer ScratchPad Index %d\n", idx);
+		return -EINVAL;
+	}
+
+	offset = (idx << 2);
+	return readl(ndev->peer_spad_reg + offset);
+}
+
+static int ntb_epf_peer_spad_write(struct ntb_dev *ntb, int pidx,
+				   int idx, u32 val)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	u32 offset;
+
+	if (pidx != NTB_DEF_PEER_IDX) {
+		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
+		return -EINVAL;
+	}
+
+	if (idx < 0 || idx >= ndev->spad_count) {
+		dev_err(dev, "WRITE: Invalid Peer ScratchPad Index %d\n", idx);
+		return -EINVAL;
+	}
+
+	offset = (idx << 2);
+	writel(val, ndev->peer_spad_reg + offset);
+
+	return 0;
+}
+
+static int ntb_epf_link_enable(struct ntb_dev *ntb,
+			       enum ntb_speed max_speed,
+			       enum ntb_width max_width)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	int ret;
+
+	ret = ntb_epf_send_command(ndev, CMD_LINK_UP, 0);
+	if (ret) {
+		dev_err(dev, "Fail to enable link\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ntb_epf_link_disable(struct ntb_dev *ntb)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	int ret;
+
+	ret = ntb_epf_send_command(ndev, CMD_LINK_DOWN, 0);
+	if (ret) {
+		dev_err(dev, "Fail to disable link\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static irqreturn_t ntb_epf_vec_isr(int irq, void *dev)
+{
+	struct ntb_epf_dev *ndev = dev;
+	int irq_no;
+
+	irq_no = irq - pci_irq_vector(ndev->ntb.pdev, 0);
+	ndev->db_val = irq_no + 1;
+
+	if (irq_no == 0)
+		ntb_link_event(&ndev->ntb);
+	else
+		ntb_db_event(&ndev->ntb, irq_no);
+
+	return IRQ_HANDLED;
+}
+
+static int ntb_epf_init_isr(struct ntb_epf_dev *ndev, int msi_min, int msi_max)
+{
+	struct pci_dev *pdev = ndev->ntb.pdev;
+	struct device *dev = ndev->dev;
+	u32 argument = MSIX_ENABLE;
+	int irq;
+	int ret;
+	int i;
+
+	irq = pci_alloc_irq_vectors(pdev, msi_min, msi_max, PCI_IRQ_MSIX);
+	if (irq < 0) {
+		dev_dbg(dev, "Failed to get MSIX interrupts\n");
+		irq = pci_alloc_irq_vectors(pdev, msi_min, msi_max,
+					    PCI_IRQ_MSI);
+		if (irq < 0) {
+			dev_err(dev, "Failed to get MSI interrupts\n");
+			return irq;
+		}
+		argument &= ~MSIX_ENABLE;
+	}
+
+	for (i = 0; i < irq; i++) {
+		ret = request_irq(pci_irq_vector(pdev, i), ntb_epf_vec_isr,
+				  0, "ntb_epf", ndev);
+		if (ret) {
+			dev_err(dev, "Failed to request irq\n");
+			goto err_request_irq;
+		}
+	}
+
+	ndev->db_count = irq - 1;
+
+	ret = ntb_epf_send_command(ndev, CMD_CONFIGURE_DOORBELL,
+				   argument | irq);
+	if (ret) {
+		dev_err(dev, "Failed to configure doorbell\n");
+		goto err_configure_db;
+	}
+
+	return 0;
+
+err_configure_db:
+	for (i = 0; i < ndev->db_count + 1; i++)
+		free_irq(pci_irq_vector(pdev, i), ndev);
+
+err_request_irq:
+	pci_free_irq_vectors(pdev);
+
+	return ret;
+}
+
+static int ntb_epf_peer_mw_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->mw_count;
+}
+
+static int ntb_epf_spad_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->spad_count;
+}
+
+static u64 ntb_epf_db_valid_mask(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->db_valid_mask;
+}
+
+static int ntb_epf_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	return 0;
+}
+
+static int ntb_epf_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
+				dma_addr_t addr, resource_size_t size)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	resource_size_t mw_size;
+	int bar;
+
+	if (pidx != NTB_DEF_PEER_IDX) {
+		dev_err(dev, "Unsupported Peer ID %d\n", pidx);
+		return -EINVAL;
+	}
+
+	bar = idx + NTB_EPF_MW_OFFSET;
+
+	mw_size = pci_resource_len(ntb->pdev, bar);
+
+	if (size > mw_size) {
+		dev_err(dev, "Size:%pa is greater than the MW size %pa\n",
+			&size, &mw_size);
+		return -EINVAL;
+	}
+
+	writel(lower_32_bits(addr), ndev->ctrl_reg + NTB_EPF_LOWER_ADDR);
+	writel(upper_32_bits(addr), ndev->ctrl_reg + NTB_EPF_UPPER_ADDR);
+	writel(lower_32_bits(size), ndev->ctrl_reg + NTB_EPF_LOWER_SIZE);
+	writel(upper_32_bits(size), ndev->ctrl_reg + NTB_EPF_UPPER_SIZE);
+	ntb_epf_send_command(ndev, CMD_CONFIGURE_MW, idx);
+
+	return 0;
+}
+
+static int ntb_epf_mw_clear_trans(struct ntb_dev *ntb, int pidx, int idx)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	struct device *dev = ndev->dev;
+	int ret = 0;
+
+	ntb_epf_send_command(ndev, CMD_TEARDOWN_MW, idx);
+	if (ret)
+		dev_err(dev, "Failed to teardown memory window\n");
+
+	return ret;
+}
+
+static int ntb_epf_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
+				    phys_addr_t *base, resource_size_t *size)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	u32 offset = 0;
+	int bar;
+
+	if (idx == 0)
+		offset = readl(ndev->ctrl_reg + NTB_EPF_MW1_OFFSET);
+
+	bar = idx + NTB_EPF_MW_OFFSET;
+
+	if (base)
+		*base = pci_resource_start(ndev->ntb.pdev, bar) + offset;
+
+	if (size)
+		*size = pci_resource_len(ndev->ntb.pdev, bar) - offset;
+
+	return 0;
+}
+
+static int ntb_epf_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+	u32 interrupt_num = ffs(db_bits) + 1;
+	struct device *dev = ndev->dev;
+	u32 db_entry_size;
+	u32 db_offset;
+	u32 db_data;
+
+	if (interrupt_num > ndev->db_count) {
+		dev_err(dev, "DB interrupt %d greater than Max Supported %d\n",
+			interrupt_num, ndev->db_count);
+		return -EINVAL;
+	}
+
+	db_entry_size = readl(ndev->ctrl_reg + NTB_EPF_DB_ENTRY_SIZE);
+
+	db_data = readl(ndev->ctrl_reg + NTB_EPF_DB_DATA(interrupt_num));
+	db_offset = readl(ndev->ctrl_reg + NTB_EPF_DB_OFFSET(interrupt_num));
+	writel(db_data, ndev->db_reg + (db_entry_size * interrupt_num) +
+	       db_offset);
+
+	return 0;
+}
+
+static u64 ntb_epf_db_read(struct ntb_dev *ntb)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+
+	return ndev->db_val;
+}
+
+static int ntb_epf_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	return 0;
+}
+
+static int ntb_epf_db_clear(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+
+	ndev->db_val = 0;
+
+	return 0;
+}
+
+static const struct ntb_dev_ops ntb_epf_ops = {
+	.mw_count		= ntb_epf_mw_count,
+	.spad_count		= ntb_epf_spad_count,
+	.peer_mw_count		= ntb_epf_peer_mw_count,
+	.db_valid_mask		= ntb_epf_db_valid_mask,
+	.db_set_mask		= ntb_epf_db_set_mask,
+	.mw_set_trans		= ntb_epf_mw_set_trans,
+	.mw_clear_trans		= ntb_epf_mw_clear_trans,
+	.peer_mw_get_addr	= ntb_epf_peer_mw_get_addr,
+	.link_enable		= ntb_epf_link_enable,
+	.spad_read		= ntb_epf_spad_read,
+	.spad_write		= ntb_epf_spad_write,
+	.peer_spad_read		= ntb_epf_peer_spad_read,
+	.peer_spad_write	= ntb_epf_peer_spad_write,
+	.peer_db_set		= ntb_epf_peer_db_set,
+	.db_read		= ntb_epf_db_read,
+	.mw_get_align		= ntb_epf_mw_get_align,
+	.link_is_up		= ntb_epf_link_is_up,
+	.db_clear_mask		= ntb_epf_db_clear_mask,
+	.db_clear		= ntb_epf_db_clear,
+	.link_disable		= ntb_epf_link_disable,
+};
+
+static inline void ntb_epf_init_struct(struct ntb_epf_dev *ndev,
+				       struct pci_dev *pdev)
+{
+	ndev->ntb.pdev = pdev;
+	ndev->ntb.topo = NTB_TOPO_NONE;
+	ndev->ntb.ops = &ntb_epf_ops;
+}
+
+static int ntb_epf_init_dev(struct ntb_epf_dev *ndev)
+{
+	struct device *dev = ndev->dev;
+	int ret;
+
+	/* One Link interrupt and rest doorbell interrupt */
+	ret = ntb_epf_init_isr(ndev, NTB_EPF_MIN_DB_COUNT + 1,
+			       NTB_EPF_MAX_DB_COUNT + 1);
+	if (ret) {
+		dev_err(dev, "Failed to init ISR\n");
+		return ret;
+	}
+
+	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
+	ndev->mw_count = readl(ndev->ctrl_reg + NTB_EPF_MW_COUNT);
+	ndev->spad_count = readl(ndev->ctrl_reg + NTB_EPF_SPAD_COUNT);
+
+	return 0;
+}
+
+static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
+			    struct pci_dev *pdev)
+{
+	struct device *dev = ndev->dev;
+	int ret;
+
+	pci_set_drvdata(pdev, ndev);
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		dev_err(dev, "Cannot enable PCI device\n");
+		goto err_pci_enable;
+	}
+
+	ret = pci_request_regions(pdev, "ntb");
+	if (ret) {
+		dev_err(dev, "Cannot obtain PCI resources\n");
+		goto err_pci_regions;
+	}
+
+	pci_set_master(pdev);
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+	if (ret) {
+		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+		if (ret) {
+			dev_err(dev, "Cannot set DMA mask\n");
+			goto err_dma_mask;
+		}
+		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
+	}
+
+	ndev->ctrl_reg = pci_iomap(pdev, ndev->ctrl_reg_bar, 0);
+	if (!ndev->ctrl_reg) {
+		ret = -EIO;
+		goto err_dma_mask;
+	}
+
+	ndev->peer_spad_reg = pci_iomap(pdev, ndev->peer_spad_reg_bar, 0);
+	if (!ndev->peer_spad_reg) {
+		ret = -EIO;
+		goto err_dma_mask;
+	}
+
+	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
+	if (!ndev->db_reg) {
+		ret = -EIO;
+		goto err_dma_mask;
+	}
+
+	return 0;
+
+err_dma_mask:
+	pci_clear_master(pdev);
+
+err_pci_regions:
+	pci_disable_device(pdev);
+
+err_pci_enable:
+	pci_set_drvdata(pdev, NULL);
+
+	return ret;
+}
+
+static void ntb_epf_deinit_pci(struct ntb_epf_dev *ndev)
+{
+	struct pci_dev *pdev = ndev->ntb.pdev;
+
+	pci_iounmap(pdev, ndev->ctrl_reg);
+	pci_iounmap(pdev, ndev->peer_spad_reg);
+	pci_iounmap(pdev, ndev->db_reg);
+
+	pci_clear_master(pdev);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	pci_set_drvdata(pdev, NULL);
+}
+
+static void ntb_epf_cleanup_isr(struct ntb_epf_dev *ndev)
+{
+	struct pci_dev *pdev = ndev->ntb.pdev;
+	int i;
+
+	ntb_epf_send_command(ndev, CMD_TEARDOWN_DOORBELL, ndev->db_count + 1);
+
+	for (i = 0; i < ndev->db_count + 1; i++)
+		free_irq(pci_irq_vector(pdev, i), ndev);
+	pci_free_irq_vectors(pdev);
+}
+
+static int ntb_epf_pci_probe(struct pci_dev *pdev,
+			     const struct pci_device_id *id)
+{
+	enum pci_barno peer_spad_reg_bar = BAR_1;
+	enum pci_barno ctrl_reg_bar = BAR_0;
+	enum pci_barno db_reg_bar = BAR_2;
+	struct device *dev = &pdev->dev;
+	struct ntb_epf_data *data;
+	struct ntb_epf_dev *ndev;
+	int ret;
+
+	if (pci_is_bridge(pdev))
+		return -ENODEV;
+
+	ndev = devm_kzalloc(dev, sizeof(*ndev), GFP_KERNEL);
+	if (!ndev)
+		return -ENOMEM;
+
+	data = (struct ntb_epf_data *)id->driver_data;
+	if (data) {
+		if (data->peer_spad_reg_bar)
+			peer_spad_reg_bar = data->peer_spad_reg_bar;
+		if (data->ctrl_reg_bar)
+			ctrl_reg_bar = data->ctrl_reg_bar;
+		if (data->db_reg_bar)
+			db_reg_bar = data->db_reg_bar;
+	}
+
+	ndev->peer_spad_reg_bar = peer_spad_reg_bar;
+	ndev->ctrl_reg_bar = ctrl_reg_bar;
+	ndev->db_reg_bar = db_reg_bar;
+	ndev->dev = dev;
+
+	ntb_epf_init_struct(ndev, pdev);
+	mutex_init(&ndev->cmd_lock);
+
+	ret = ntb_epf_init_pci(ndev, pdev);
+	if (ret) {
+		dev_err(dev, "Failed to init PCI\n");
+		return ret;
+	}
+
+	ret = ntb_epf_init_dev(ndev);
+	if (ret) {
+		dev_err(dev, "Failed to init device\n");
+		goto err_init_dev;
+	}
+
+	ret = ntb_register_device(&ndev->ntb);
+	if (ret) {
+		dev_err(dev, "Failed to register NTB device\n");
+		goto err_register_dev;
+	}
+
+	return 0;
+
+err_register_dev:
+	ntb_epf_cleanup_isr(ndev);
+
+err_init_dev:
+	ntb_epf_deinit_pci(ndev);
+
+	return ret;
+}
+
+static void ntb_epf_pci_remove(struct pci_dev *pdev)
+{
+	struct ntb_epf_dev *ndev = pci_get_drvdata(pdev);
+
+	ntb_unregister_device(&ndev->ntb);
+	ntb_epf_cleanup_isr(ndev);
+	ntb_epf_deinit_pci(ndev);
+}
+
+static const struct ntb_epf_data j721e_data = {
+	.ctrl_reg_bar = BAR_0,
+	.peer_spad_reg_bar = BAR_1,
+	.db_reg_bar = BAR_2,
+};
+
+static const struct pci_device_id ntb_epf_pci_tbl[] = {
+	{
+		PCI_DEVICE(PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_J721E),
+		.class = PCI_CLASS_MEMORY_RAM << 8, .class_mask = 0xffff00,
+		.driver_data = (kernel_ulong_t)&j721e_data,
+	},
+	{ },
+};
+
+static struct pci_driver ntb_epf_pci_driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= ntb_epf_pci_tbl,
+	.probe		= ntb_epf_pci_probe,
+	.remove		= ntb_epf_pci_remove,
+};
+module_pci_driver(ntb_epf_pci_driver);
+
+MODULE_DESCRIPTION("PCI ENDPOINT NTB HOST DRIVER");
+MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index 9e2b024d32f2..897cdde02bd8 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -382,6 +382,57 @@ static int cdns_pcie_ep_send_msi_irq(struct cdns_pcie_ep *ep, u8 fn,
 	return 0;
 }
 
+static int cdns_pcie_ep_map_msi_irq(struct pci_epc *epc, u8 fn,
+				    phys_addr_t addr, u8 interrupt_num,
+				    u32 entry_size, u32 *msi_data,
+				    u32 *msi_addr_offset)
+{
+	struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
+	u32 cap = CDNS_PCIE_EP_FUNC_MSI_CAP_OFFSET;
+	struct cdns_pcie *pcie = &ep->pcie;
+	u64 pci_addr, pci_addr_mask = 0xff;
+	u16 flags, mme, data, data_mask;
+	u8 msi_count;
+	int ret;
+	int i;
+
+	/* Check whether the MSI feature has been enabled by the PCI host. */
+	flags = cdns_pcie_ep_fn_readw(pcie, fn, cap + PCI_MSI_FLAGS);
+	if (!(flags & PCI_MSI_FLAGS_ENABLE))
+		return -EINVAL;
+
+	/* Get the number of enabled MSIs */
+	mme = (flags & PCI_MSI_FLAGS_QSIZE) >> 4;
+	msi_count = 1 << mme;
+	if (!interrupt_num || interrupt_num > msi_count)
+		return -EINVAL;
+
+	/* Compute the data value to be written. */
+	data_mask = msi_count - 1;
+	data = cdns_pcie_ep_fn_readw(pcie, fn, cap + PCI_MSI_DATA_64);
+	data = data & ~data_mask;
+
+	/* Get the PCI address where to write the data into. */
+	pci_addr = cdns_pcie_ep_fn_readl(pcie, fn, cap + PCI_MSI_ADDRESS_HI);
+	pci_addr <<= 32;
+	pci_addr |= cdns_pcie_ep_fn_readl(pcie, fn, cap + PCI_MSI_ADDRESS_LO);
+	pci_addr &= GENMASK_ULL(63, 2);
+
+	for (i = 0; i < interrupt_num; i++) {
+		ret = cdns_pcie_ep_map_addr(epc, fn, addr,
+					    pci_addr & ~pci_addr_mask,
+					    entry_size);
+		if (ret)
+			return ret;
+		addr = addr + entry_size;
+	}
+
+	*msi_data = data;
+	*msi_addr_offset = pci_addr & pci_addr_mask;
+
+	return 0;
+}
+
 static int cdns_pcie_ep_send_msix_irq(struct cdns_pcie_ep *ep, u8 fn,
 				      u16 interrupt_num)
 {
@@ -455,18 +506,13 @@ static int cdns_pcie_ep_start(struct pci_epc *epc)
 	struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
 	struct cdns_pcie *pcie = &ep->pcie;
 	struct device *dev = pcie->dev;
-	struct pci_epf *epf;
-	u32 cfg;
 	int ret;
 
 	/*
 	 * BIT(0) is hardwired to 1, hence function 0 is always enabled
 	 * and can't be disabled anyway.
 	 */
-	cfg = BIT(0);
-	list_for_each_entry(epf, &epc->pci_epf, list)
-		cfg |= BIT(epf->func_no);
-	cdns_pcie_writel(pcie, CDNS_PCIE_LM_EP_FUNC_CFG, cfg);
+	cdns_pcie_writel(pcie, CDNS_PCIE_LM_EP_FUNC_CFG, epc->function_num_map);
 
 	ret = cdns_pcie_start_link(pcie);
 	if (ret) {
@@ -481,6 +527,7 @@ static const struct pci_epc_features cdns_pcie_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
 	.msix_capable = true,
+	.align = 256,
 };
 
 static const struct pci_epc_features*
@@ -500,6 +547,7 @@ static const struct pci_epc_ops cdns_pcie_epc_ops = {
 	.set_msix	= cdns_pcie_ep_set_msix,
 	.get_msix	= cdns_pcie_ep_get_msix,
 	.raise_irq	= cdns_pcie_ep_raise_irq,
+	.map_msi_irq	= cdns_pcie_ep_map_msi_irq,
 	.start		= cdns_pcie_ep_start,
 	.get_features	= cdns_pcie_ep_get_features,
 };
diff --git a/drivers/pci/endpoint/functions/Kconfig b/drivers/pci/endpoint/functions/Kconfig
index 8820d0f7ec77..5f1242ca2f4e 100644
--- a/drivers/pci/endpoint/functions/Kconfig
+++ b/drivers/pci/endpoint/functions/Kconfig
@@ -12,3 +12,16 @@ config PCI_EPF_TEST
 	   for PCI Endpoint.
 
 	   If in doubt, say "N" to disable Endpoint test driver.
+
+config PCI_EPF_NTB
+	tristate "PCI Endpoint NTB driver"
+	depends on PCI_ENDPOINT
+	select CONFIGFS_FS
+	help
+	  Select this configuration option to enable the Non-Transparent
+	  Bridge (NTB) driver for PCI Endpoint. NTB driver implements NTB
+	  controller functionality using multiple PCIe endpoint instances.
+	  It can support NTB endpoint function devices created using
+	  device tree.
+
+	  If in doubt, say "N" to disable Endpoint NTB driver.
diff --git a/drivers/pci/endpoint/functions/Makefile b/drivers/pci/endpoint/functions/Makefile
index d6fafff080e2..96ab932a537a 100644
--- a/drivers/pci/endpoint/functions/Makefile
+++ b/drivers/pci/endpoint/functions/Makefile
@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_PCI_EPF_TEST)		+= pci-epf-test.o
+obj-$(CONFIG_PCI_EPF_NTB)		+= pci-epf-ntb.o
diff --git a/drivers/pci/endpoint/functions/pci-epf-ntb.c b/drivers/pci/endpoint/functions/pci-epf-ntb.c
new file mode 100644
index 000000000000..338148cf56f5
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-ntb.c
@@ -0,0 +1,2128 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Endpoint Function Driver to implement Non-Transparent Bridge functionality
+ *
+ * Copyright (C) 2020 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ */
+
+/*
+ * The PCI NTB function driver configures the SoC with multiple PCIe Endpoint
+ * (EP) controller instances (see diagram below) in such a way that
+ * transactions from one EP controller are routed to the other EP controller.
+ * Once PCI NTB function driver configures the SoC with multiple EP instances,
+ * HOST1 and HOST2 can communicate with each other using SoC as a bridge.
+ *
+ *    +-------------+                                   +-------------+
+ *    |             |                                   |             |
+ *    |    HOST1    |                                   |    HOST2    |
+ *    |             |                                   |             |
+ *    +------^------+                                   +------^------+
+ *           |                                                 |
+ *           |                                                 |
+ * +---------|-------------------------------------------------|---------+
+ * |  +------v------+                                   +------v------+  |
+ * |  |             |                                   |             |  |
+ * |  |     EP      |                                   |     EP      |  |
+ * |  | CONTROLLER1 |                                   | CONTROLLER2 |  |
+ * |  |             <----------------------------------->             |  |
+ * |  |             |                                   |             |  |
+ * |  |             |                                   |             |  |
+ * |  |             |  SoC With Multiple EP Instances   |             |  |
+ * |  |             |  (Configured using NTB Function)  |             |  |
+ * |  +-------------+                                   +-------------+  |
+ * +---------------------------------------------------------------------+
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <linux/pci-epc.h>
+#include <linux/pci-epf.h>
+
+static struct workqueue_struct *kpcintb_workqueue;
+
+#define COMMAND_CONFIGURE_DOORBELL	1
+#define COMMAND_TEARDOWN_DOORBELL	2
+#define COMMAND_CONFIGURE_MW		3
+#define COMMAND_TEARDOWN_MW		4
+#define COMMAND_LINK_UP			5
+#define COMMAND_LINK_DOWN		6
+
+#define COMMAND_STATUS_OK		1
+#define COMMAND_STATUS_ERROR		2
+
+#define LINK_STATUS_UP			BIT(0)
+
+#define SPAD_COUNT			64
+#define DB_COUNT			4
+#define NTB_MW_OFFSET			2
+#define DB_COUNT_MASK			GENMASK(15, 0)
+#define MSIX_ENABLE			BIT(16)
+#define MAX_DB_COUNT			32
+#define MAX_MW				4
+
+enum epf_ntb_bar {
+	BAR_CONFIG,
+	BAR_PEER_SPAD,
+	BAR_DB_MW1,
+	BAR_MW2,
+	BAR_MW3,
+	BAR_MW4,
+};
+
+struct epf_ntb {
+	u32 num_mws;
+	u32 db_count;
+	u32 spad_count;
+	struct pci_epf *epf;
+	u64 mws_size[MAX_MW];
+	struct config_group group;
+	struct epf_ntb_epc *epc[2];
+};
+
+#define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group)
+
+struct epf_ntb_epc {
+	u8 func_no;
+	bool linkup;
+	bool is_msix;
+	int msix_bar;
+	u32 spad_size;
+	struct pci_epc *epc;
+	struct epf_ntb *epf_ntb;
+	void __iomem *mw_addr[6];
+	size_t msix_table_offset;
+	struct epf_ntb_ctrl *reg;
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno epf_ntb_bar[6];
+	struct delayed_work cmd_handler;
+	enum pci_epc_interface_type type;
+	const struct pci_epc_features *epc_features;
+};
+
+struct epf_ntb_ctrl {
+	u32	command;
+	u32	argument;
+	u16	command_status;
+	u16	link_status;
+	u32	topology;
+	u64	addr;
+	u64	size;
+	u32	num_mws;
+	u32	mw1_offset;
+	u32	spad_offset;
+	u32	spad_count;
+	u32	db_entry_size;
+	u32	db_data[MAX_DB_COUNT];
+	u32	db_offset[MAX_DB_COUNT];
+} __packed;
+
+static struct pci_epf_header epf_ntb_header = {
+	.vendorid	= PCI_ANY_ID,
+	.deviceid	= PCI_ANY_ID,
+	.baseclass_code	= PCI_BASE_CLASS_MEMORY,
+	.interrupt_pin	= PCI_INTERRUPT_INTA,
+};
+
+/**
+ * epf_ntb_link_up() - Raise link_up interrupt to both the hosts
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @link_up: true or false indicating Link is UP or Down
+ *
+ * Once NTB function in HOST1 and the NTB function in HOST2 invoke
+ * ntb_link_enable(), this NTB function driver will trigger a link event to
+ * the NTB client in both the hosts.
+ */
+static int epf_ntb_link_up(struct epf_ntb *ntb, bool link_up)
+{
+	enum pci_epc_interface_type type;
+	enum pci_epc_irq_type irq_type;
+	struct epf_ntb_epc *ntb_epc;
+	struct epf_ntb_ctrl *ctrl;
+	struct pci_epc *epc;
+	bool is_msix;
+	u8 func_no;
+	int ret;
+
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++) {
+		ntb_epc = ntb->epc[type];
+		epc = ntb_epc->epc;
+		func_no = ntb_epc->func_no;
+		is_msix = ntb_epc->is_msix;
+		ctrl = ntb_epc->reg;
+		if (link_up)
+			ctrl->link_status |= LINK_STATUS_UP;
+		else
+			ctrl->link_status &= ~LINK_STATUS_UP;
+		irq_type = is_msix ? PCI_EPC_IRQ_MSIX : PCI_EPC_IRQ_MSI;
+		ret = pci_epc_raise_irq(epc, func_no, irq_type, 1);
+		if (ret) {
+			dev_err(&epc->dev,
+				"%s intf: Failed to raise Link Up IRQ\n",
+				pci_epc_interface_string(type));
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_configure_mw() - Configure the Outbound Address Space for one host
+ *   to access the memory window of other host
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ * @mw: Index of the memory window (either 0, 1, 2 or 3)
+ *
+ * +-----------------+    +---->+----------------+-----------+-----------------+
+ * |       BAR0      |    |     |   Doorbell 1   +-----------> MSI|X ADDRESS 1 |
+ * +-----------------+    |     +----------------+           +-----------------+
+ * |       BAR1      |    |     |   Doorbell 2   +---------+ |                 |
+ * +-----------------+----+     +----------------+         | |                 |
+ * |       BAR2      |          |   Doorbell 3   +-------+ | +-----------------+
+ * +-----------------+----+     +----------------+       | +-> MSI|X ADDRESS 2 |
+ * |       BAR3      |    |     |   Doorbell 4   +-----+ |   +-----------------+
+ * +-----------------+    |     |----------------+     | |   |                 |
+ * |       BAR4      |    |     |                |     | |   +-----------------+
+ * +-----------------+    |     |      MW1       +---+ | +-->+ MSI|X ADDRESS 3||
+ * |       BAR5      |    |     |                |   | |     +-----------------+
+ * +-----------------+    +---->-----------------+   | |     |                 |
+ *   EP CONTROLLER 1            |                |   | |     +-----------------+
+ *                              |                |   | +---->+ MSI|X ADDRESS 4 |
+ *                              +----------------+   |       +-----------------+
+ *                      (A)      EP CONTROLLER 2     |       |                 |
+ *                                 (OB SPACE)        |       |                 |
+ *                                                   +------->      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ * This function performs stage (B) in the above diagram (see MW1) i.e., map OB
+ * address space of memory window to PCI address space.
+ *
+ * This operation requires 3 parameters
+ *  1) Address in the outbound address space
+ *  2) Address in the PCI Address space
+ *  3) Size of the address region to be mapped
+ *
+ * The address in the outbound address space (for MW1, MW2, MW3 and MW4) is
+ * stored in epf_bar corresponding to BAR_DB_MW1 for MW1 and BAR_MW2, BAR_MW3
+ * BAR_MW4 for rest of the BARs of epf_ntb_epc that is connected to HOST1. This
+ * is populated in epf_ntb_alloc_peer_mem() in this driver.
+ *
+ * The address and size of the PCI address region that has to be mapped would
+ * be provided by HOST2 in ctrl->addr and ctrl->size of epf_ntb_epc that is
+ * connected to HOST2.
+ *
+ * Please note Memory window1 (MW1) and Doorbell registers together will be
+ * mapped to a single BAR (BAR2) above for 32-bit BARs. The exact BAR that's
+ * used for Memory window (MW) can be obtained from epf_ntb_bar[BAR_DB_MW1],
+ * epf_ntb_bar[BAR_MW2], epf_ntb_bar[BAR_MW2], epf_ntb_bar[BAR_MW2].
+ */
+static int epf_ntb_configure_mw(struct epf_ntb *ntb,
+				enum pci_epc_interface_type type, u32 mw)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *peer_epf_bar;
+	enum pci_barno peer_barno;
+	struct epf_ntb_ctrl *ctrl;
+	phys_addr_t phys_addr;
+	struct pci_epc *epc;
+	u64 addr, size;
+	int ret = 0;
+	u8 func_no;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[mw + NTB_MW_OFFSET];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+
+	phys_addr = peer_epf_bar->phys_addr;
+	ctrl = ntb_epc->reg;
+	addr = ctrl->addr;
+	size = ctrl->size;
+	if (mw + NTB_MW_OFFSET == BAR_DB_MW1)
+		phys_addr += ctrl->mw1_offset;
+
+	if (size > ntb->mws_size[mw]) {
+		dev_err(&epc->dev,
+			"%s intf: MW: %d Req Sz:%llxx > Supported Sz:%llx\n",
+			pci_epc_interface_string(type), mw, size,
+			ntb->mws_size[mw]);
+		ret = -EINVAL;
+		goto err_invalid_size;
+	}
+
+	func_no = ntb_epc->func_no;
+
+	ret = pci_epc_map_addr(epc, func_no, phys_addr, addr, size);
+	if (ret)
+		dev_err(&epc->dev,
+			"%s intf: Failed to map memory window %d address\n",
+			pci_epc_interface_string(type), mw);
+
+err_invalid_size:
+
+	return ret;
+}
+
+/**
+ * epf_ntb_teardown_mw() - Teardown the configured OB ATU
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ * @mw: Index of the memory window (either 0, 1, 2 or 3)
+ *
+ * Teardown the configured OB ATU configured in epf_ntb_configure_mw() using
+ * pci_epc_unmap_addr()
+ */
+static void epf_ntb_teardown_mw(struct epf_ntb *ntb,
+				enum pci_epc_interface_type type, u32 mw)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *peer_epf_bar;
+	enum pci_barno peer_barno;
+	struct epf_ntb_ctrl *ctrl;
+	phys_addr_t phys_addr;
+	struct pci_epc *epc;
+	u8 func_no;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[mw + NTB_MW_OFFSET];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+
+	phys_addr = peer_epf_bar->phys_addr;
+	ctrl = ntb_epc->reg;
+	if (mw + NTB_MW_OFFSET == BAR_DB_MW1)
+		phys_addr += ctrl->mw1_offset;
+	func_no = ntb_epc->func_no;
+
+	pci_epc_unmap_addr(epc, func_no, phys_addr);
+}
+
+/**
+ * epf_ntb_configure_msi() - Map OB address space to MSI address
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ * @db_count: Number of doorbell interrupts to map
+ *
+ *+-----------------+    +----->+----------------+-----------+-----------------+
+ *|       BAR0      |    |      |   Doorbell 1   +---+------->   MSI ADDRESS   |
+ *+-----------------+    |      +----------------+   |       +-----------------+
+ *|       BAR1      |    |      |   Doorbell 2   +---+       |                 |
+ *+-----------------+----+      +----------------+   |       |                 |
+ *|       BAR2      |           |   Doorbell 3   +---+       |                 |
+ *+-----------------+----+      +----------------+   |       |                 |
+ *|       BAR3      |    |      |   Doorbell 4   +---+       |                 |
+ *+-----------------+    |      |----------------+           |                 |
+ *|       BAR4      |    |      |                |           |                 |
+ *+-----------------+    |      |      MW1       |           |                 |
+ *|       BAR5      |    |      |                |           |                 |
+ *+-----------------+    +----->-----------------+           |                 |
+ *  EP CONTROLLER 1             |                |           |                 |
+ *                              |                |           |                 |
+ *                              +----------------+           +-----------------+
+ *                     (A)       EP CONTROLLER 2             |                 |
+ *                                 (OB SPACE)                |                 |
+ *                                                           |      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ *
+ * This function performs stage (B) in the above diagram (see Doorbell 1,
+ * Doorbell 2, Doorbell 3, Doorbell 4) i.e map OB address space corresponding to
+ * doorbell to MSI address in PCI address space.
+ *
+ * This operation requires 3 parameters
+ *  1) Address reserved for doorbell in the outbound address space
+ *  2) MSI-X address in the PCIe Address space
+ *  3) Number of MSI-X interrupts that has to be configured
+ *
+ * The address in the outbound address space (for the Doorbell) is stored in
+ * epf_bar corresponding to BAR_DB_MW1 of epf_ntb_epc that is connected to
+ * HOST1. This is populated in epf_ntb_alloc_peer_mem() in this driver along
+ * with address for MW1.
+ *
+ * pci_epc_map_msi_irq() takes the MSI address from MSI capability register
+ * and maps the OB address (obtained in epf_ntb_alloc_peer_mem()) to the MSI
+ * address.
+ *
+ * epf_ntb_configure_msi() also stores the MSI data to raise each interrupt
+ * in db_data of the peer's control region. This helps the peer to raise
+ * doorbell of the other host by writing db_data to the BAR corresponding to
+ * BAR_DB_MW1.
+ */
+static int epf_ntb_configure_msi(struct epf_ntb *ntb,
+				 enum pci_epc_interface_type type, u16 db_count)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	u32 db_entry_size, db_data, db_offset;
+	struct pci_epf_bar *peer_epf_bar;
+	struct epf_ntb_ctrl *peer_ctrl;
+	enum pci_barno peer_barno;
+	phys_addr_t phys_addr;
+	struct pci_epc *epc;
+	u8 func_no;
+	int ret, i;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[BAR_DB_MW1];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+	peer_ctrl = peer_ntb_epc->reg;
+	db_entry_size = peer_ctrl->db_entry_size;
+
+	phys_addr = peer_epf_bar->phys_addr;
+	func_no = ntb_epc->func_no;
+
+	ret = pci_epc_map_msi_irq(epc, func_no, phys_addr, db_count,
+				  db_entry_size, &db_data, &db_offset);
+	if (ret) {
+		dev_err(&epc->dev, "%s intf: Failed to map MSI IRQ\n",
+			pci_epc_interface_string(type));
+		return ret;
+	}
+
+	for (i = 0; i < db_count; i++) {
+		peer_ctrl->db_data[i] = db_data | i;
+		peer_ctrl->db_offset[i] = db_offset;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_configure_msix() - Map OB address space to MSI-X address
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ * @db_count: Number of doorbell interrupts to map
+ *
+ *+-----------------+    +----->+----------------+-----------+-----------------+
+ *|       BAR0      |    |      |   Doorbell 1   +-----------> MSI-X ADDRESS 1 |
+ *+-----------------+    |      +----------------+           +-----------------+
+ *|       BAR1      |    |      |   Doorbell 2   +---------+ |                 |
+ *+-----------------+----+      +----------------+         | |                 |
+ *|       BAR2      |           |   Doorbell 3   +-------+ | +-----------------+
+ *+-----------------+----+      +----------------+       | +-> MSI-X ADDRESS 2 |
+ *|       BAR3      |    |      |   Doorbell 4   +-----+ |   +-----------------+
+ *+-----------------+    |      |----------------+     | |   |                 |
+ *|       BAR4      |    |      |                |     | |   +-----------------+
+ *+-----------------+    |      |      MW1       +     | +-->+ MSI-X ADDRESS 3||
+ *|       BAR5      |    |      |                |     |     +-----------------+
+ *+-----------------+    +----->-----------------+     |     |                 |
+ *  EP CONTROLLER 1             |                |     |     +-----------------+
+ *                              |                |     +---->+ MSI-X ADDRESS 4 |
+ *                              +----------------+           +-----------------+
+ *                     (A)       EP CONTROLLER 2             |                 |
+ *                                 (OB SPACE)                |                 |
+ *                                                           |      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ * This function performs stage (B) in the above diagram (see Doorbell 1,
+ * Doorbell 2, Doorbell 3, Doorbell 4) i.e map OB address space corresponding to
+ * doorbell to MSI-X address in PCI address space.
+ *
+ * This operation requires 3 parameters
+ *  1) Address reserved for doorbell in the outbound address space
+ *  2) MSI-X address in the PCIe Address space
+ *  3) Number of MSI-X interrupts that has to be configured
+ *
+ * The address in the outbound address space (for the Doorbell) is stored in
+ * epf_bar corresponding to BAR_DB_MW1 of epf_ntb_epc that is connected to
+ * HOST1. This is populated in epf_ntb_alloc_peer_mem() in this driver along
+ * with address for MW1.
+ *
+ * The MSI-X address is in the MSI-X table of EP CONTROLLER 2 and
+ * the count of doorbell is in ctrl->argument of epf_ntb_epc that is connected
+ * to HOST2. MSI-X table is stored memory mapped to ntb_epc->msix_bar and the
+ * offset is in ntb_epc->msix_table_offset. From this epf_ntb_configure_msix()
+ * gets the MSI-X address and data.
+ *
+ * epf_ntb_configure_msix() also stores the MSI-X data to raise each interrupt
+ * in db_data of the peer's control region. This helps the peer to raise
+ * doorbell of the other host by writing db_data to the BAR corresponding to
+ * BAR_DB_MW1.
+ */
+static int epf_ntb_configure_msix(struct epf_ntb *ntb,
+				  enum pci_epc_interface_type type,
+				  u16 db_count)
+{
+	const struct pci_epc_features *epc_features;
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *peer_epf_bar, *epf_bar;
+	struct pci_epf_msix_tbl *msix_tbl;
+	struct epf_ntb_ctrl *peer_ctrl;
+	u32 db_entry_size, msg_data;
+	enum pci_barno peer_barno;
+	phys_addr_t phys_addr;
+	struct pci_epc *epc;
+	size_t align;
+	u64 msg_addr;
+	u8 func_no;
+	int ret, i;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	epf_bar = &ntb_epc->epf_bar[ntb_epc->msix_bar];
+	msix_tbl = epf_bar->addr + ntb_epc->msix_table_offset;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[BAR_DB_MW1];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+	phys_addr = peer_epf_bar->phys_addr;
+	peer_ctrl = peer_ntb_epc->reg;
+	epc_features = ntb_epc->epc_features;
+	align = epc_features->align;
+
+	func_no = ntb_epc->func_no;
+	db_entry_size = peer_ctrl->db_entry_size;
+
+	for (i = 0; i < db_count; i++) {
+		msg_addr = ALIGN_DOWN(msix_tbl[i].msg_addr, align);
+		msg_data = msix_tbl[i].msg_data;
+		ret = pci_epc_map_addr(epc, func_no, phys_addr, msg_addr,
+				       db_entry_size);
+		if (ret) {
+			dev_err(&epc->dev,
+				"%s intf: Failed to configure MSI-X IRQ\n",
+				pci_epc_interface_string(type));
+			return ret;
+		}
+		phys_addr = phys_addr + db_entry_size;
+		peer_ctrl->db_data[i] = msg_data;
+		peer_ctrl->db_offset[i] = msix_tbl[i].msg_addr & (align - 1);
+	}
+	ntb_epc->is_msix = true;
+
+	return 0;
+}
+
+/**
+ * epf_ntb_configure_db() - Configure the Outbound Address Space for one host
+ *   to ring the doorbell of other host
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ * @db_count: Count of the number of doorbells that has to be configured
+ * @msix: Indicates whether MSI-X or MSI should be used
+ *
+ * Invokes epf_ntb_configure_msix() or epf_ntb_configure_msi() required for
+ * one HOST to ring the doorbell of other HOST.
+ */
+static int epf_ntb_configure_db(struct epf_ntb *ntb,
+				enum pci_epc_interface_type type,
+				u16 db_count, bool msix)
+{
+	struct epf_ntb_epc *ntb_epc;
+	struct pci_epc *epc;
+	int ret;
+
+	if (db_count > MAX_DB_COUNT)
+		return -EINVAL;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	if (msix)
+		ret = epf_ntb_configure_msix(ntb, type, db_count);
+	else
+		ret = epf_ntb_configure_msi(ntb, type, db_count);
+
+	if (ret)
+		dev_err(&epc->dev, "%s intf: Failed to configure DB\n",
+			pci_epc_interface_string(type));
+
+	return ret;
+}
+
+/**
+ * epf_ntb_teardown_db() - Unmap address in OB address space to MSI/MSI-X
+ *   address
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Invoke pci_epc_unmap_addr() to unmap OB address to MSI/MSI-X address.
+ */
+static void
+epf_ntb_teardown_db(struct epf_ntb *ntb, enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *peer_epf_bar;
+	enum pci_barno peer_barno;
+	phys_addr_t phys_addr;
+	struct pci_epc *epc;
+	u8 func_no;
+
+	ntb_epc = ntb->epc[type];
+	epc = ntb_epc->epc;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[BAR_DB_MW1];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+	phys_addr = peer_epf_bar->phys_addr;
+	func_no = ntb_epc->func_no;
+
+	pci_epc_unmap_addr(epc, func_no, phys_addr);
+}
+
+/**
+ * epf_ntb_cmd_handler() - Handle commands provided by the NTB Host
+ * @work: work_struct for the two epf_ntb_epc (PRIMARY and SECONDARY)
+ *
+ * Workqueue function that gets invoked for the two epf_ntb_epc
+ * periodically (once every 5ms) to see if it has received any commands
+ * from NTB host. The host can send commands to configure doorbell or
+ * configure memory window or to update link status.
+ */
+static void epf_ntb_cmd_handler(struct work_struct *work)
+{
+	enum pci_epc_interface_type type;
+	struct epf_ntb_epc *ntb_epc;
+	struct epf_ntb_ctrl *ctrl;
+	u32 command, argument;
+	struct epf_ntb *ntb;
+	struct device *dev;
+	u16 db_count;
+	bool is_msix;
+	int ret;
+
+	ntb_epc = container_of(work, struct epf_ntb_epc, cmd_handler.work);
+	ctrl = ntb_epc->reg;
+	command = ctrl->command;
+	if (!command)
+		goto reset_handler;
+	argument = ctrl->argument;
+
+	ctrl->command = 0;
+	ctrl->argument = 0;
+
+	ctrl = ntb_epc->reg;
+	type = ntb_epc->type;
+	ntb = ntb_epc->epf_ntb;
+	dev = &ntb->epf->dev;
+
+	switch (command) {
+	case COMMAND_CONFIGURE_DOORBELL:
+		db_count = argument & DB_COUNT_MASK;
+		is_msix = argument & MSIX_ENABLE;
+		ret = epf_ntb_configure_db(ntb, type, db_count, is_msix);
+		if (ret < 0)
+			ctrl->command_status = COMMAND_STATUS_ERROR;
+		else
+			ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_TEARDOWN_DOORBELL:
+		epf_ntb_teardown_db(ntb, type);
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_CONFIGURE_MW:
+		ret = epf_ntb_configure_mw(ntb, type, argument);
+		if (ret < 0)
+			ctrl->command_status = COMMAND_STATUS_ERROR;
+		else
+			ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_TEARDOWN_MW:
+		epf_ntb_teardown_mw(ntb, type, argument);
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_LINK_UP:
+		ntb_epc->linkup = true;
+		if (ntb->epc[PRIMARY_INTERFACE]->linkup &&
+		    ntb->epc[SECONDARY_INTERFACE]->linkup) {
+			ret = epf_ntb_link_up(ntb, true);
+			if (ret < 0)
+				ctrl->command_status = COMMAND_STATUS_ERROR;
+			else
+				ctrl->command_status = COMMAND_STATUS_OK;
+			goto reset_handler;
+		}
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_LINK_DOWN:
+		ntb_epc->linkup = false;
+		ret = epf_ntb_link_up(ntb, false);
+		if (ret < 0)
+			ctrl->command_status = COMMAND_STATUS_ERROR;
+		else
+			ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	default:
+		dev_err(dev, "%s intf UNKNOWN command: %d\n",
+			pci_epc_interface_string(type), command);
+		break;
+	}
+
+reset_handler:
+	queue_delayed_work(kpcintb_workqueue, &ntb_epc->cmd_handler,
+			   msecs_to_jiffies(5));
+}
+
+/**
+ * epf_ntb_peer_spad_bar_clear() - Clear Peer Scratchpad BAR
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ *+-----------------+------->+------------------+        +-----------------+
+ *|       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ *+-----------------+----+   +------------------+<-------+-----------------+
+ *|       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ *+-----------------+    +-->+------------------+<-------+-----------------+
+ *|       BAR2      |            Local Memory            |       BAR2      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR3      |                                    |       BAR3      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR4      |                                    |       BAR4      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR5      |                                    |       BAR5      |
+ *+-----------------+                                    +-----------------+
+ *  EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Clear BAR1 of EP CONTROLLER 2 which contains the HOST2's peer scratchpad
+ * region. While BAR1 is the default peer scratchpad BAR, an NTB could have
+ * other BARs for peer scratchpad (because of 64-bit BARs or reserved BARs).
+ * This function can get the exact BAR used for peer scratchpad from
+ * epf_ntb_bar[BAR_PEER_SPAD].
+ *
+ * Since HOST2's peer scratchpad is also HOST1's self scratchpad, this function
+ * gets the address of peer scratchpad from
+ * peer_ntb_epc->epf_ntb_bar[BAR_CONFIG].
+ */
+static void epf_ntb_peer_spad_bar_clear(struct epf_ntb_epc *ntb_epc)
+{
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+	struct pci_epc *epc;
+	u8 func_no;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_PEER_SPAD];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	pci_epc_clear_bar(epc, func_no, epf_bar);
+}
+
+/**
+ * epf_ntb_peer_spad_bar_set() - Set peer scratchpad BAR
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ *+-----------------+------->+------------------+        +-----------------+
+ *|       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ *+-----------------+----+   +------------------+<-------+-----------------+
+ *|       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ *+-----------------+    +-->+------------------+<-------+-----------------+
+ *|       BAR2      |            Local Memory            |       BAR2      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR3      |                                    |       BAR3      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR4      |                                    |       BAR4      |
+ *+-----------------+                                    +-----------------+
+ *|       BAR5      |                                    |       BAR5      |
+ *+-----------------+                                    +-----------------+
+ *  EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Set BAR1 of EP CONTROLLER 2 which contains the HOST2's peer scratchpad
+ * region. While BAR1 is the default peer scratchpad BAR, an NTB could have
+ * other BARs for peer scratchpad (because of 64-bit BARs or reserved BARs).
+ * This function can get the exact BAR used for peer scratchpad from
+ * epf_ntb_bar[BAR_PEER_SPAD].
+ *
+ * Since HOST2's peer scratchpad is also HOST1's self scratchpad, this function
+ * gets the address of peer scratchpad from
+ * peer_ntb_epc->epf_ntb_bar[BAR_CONFIG].
+ */
+static int epf_ntb_peer_spad_bar_set(struct epf_ntb *ntb,
+				     enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *peer_epf_bar, *epf_bar;
+	enum pci_barno peer_barno, barno;
+	u32 peer_spad_offset;
+	struct pci_epc *epc;
+	struct device *dev;
+	u8 func_no;
+	int ret;
+
+	dev = &ntb->epf->dev;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_barno = peer_ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	peer_epf_bar = &peer_ntb_epc->epf_bar[peer_barno];
+
+	ntb_epc = ntb->epc[type];
+	barno = ntb_epc->epf_ntb_bar[BAR_PEER_SPAD];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	func_no = ntb_epc->func_no;
+	epc = ntb_epc->epc;
+
+	peer_spad_offset = peer_ntb_epc->reg->spad_offset;
+	epf_bar->phys_addr = peer_epf_bar->phys_addr + peer_spad_offset;
+	epf_bar->size = peer_ntb_epc->spad_size;
+	epf_bar->barno = barno;
+	epf_bar->flags = PCI_BASE_ADDRESS_MEM_TYPE_32;
+
+	ret = pci_epc_set_bar(epc, func_no, epf_bar);
+	if (ret) {
+		dev_err(dev, "%s intf: peer SPAD BAR set failed\n",
+			pci_epc_interface_string(type));
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_config_sspad_bar_clear() - Clear Config + Self scratchpad BAR
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ * +-----------------+----+   +------------------+<-------+-----------------+
+ * |       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ * +-----------------+    +-->+------------------+<-------+-----------------+
+ * |       BAR2      |            Local Memory            |       BAR2      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR3      |                                    |       BAR3      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR4      |                                    |       BAR4      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR5      |                                    |       BAR5      |
+ * +-----------------+                                    +-----------------+
+ *   EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Clear BAR0 of EP CONTROLLER 1 which contains the HOST1's config and
+ * self scratchpad region (removes inbound ATU configuration). While BAR0 is
+ * the default self scratchpad BAR, an NTB could have other BARs for self
+ * scratchpad (because of reserved BARs). This function can get the exact BAR
+ * used for self scratchpad from epf_ntb_bar[BAR_CONFIG].
+ *
+ * Please note the self scratchpad region and config region is combined to
+ * a single region and mapped using the same BAR. Also note HOST2's peer
+ * scratchpad is HOST1's self scratchpad.
+ */
+static void epf_ntb_config_sspad_bar_clear(struct epf_ntb_epc *ntb_epc)
+{
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+	struct pci_epc *epc;
+	u8 func_no;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	pci_epc_clear_bar(epc, func_no, epf_bar);
+}
+
+/**
+ * epf_ntb_config_sspad_bar_set() - Set Config + Self scratchpad BAR
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ * +-----------------+----+   +------------------+<-------+-----------------+
+ * |       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ * +-----------------+    +-->+------------------+<-------+-----------------+
+ * |       BAR2      |            Local Memory            |       BAR2      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR3      |                                    |       BAR3      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR4      |                                    |       BAR4      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR5      |                                    |       BAR5      |
+ * +-----------------+                                    +-----------------+
+ *   EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Map BAR0 of EP CONTROLLER 1 which contains the HOST1's config and
+ * self scratchpad region. While BAR0 is the default self scratchpad BAR, an
+ * NTB could have other BARs for self scratchpad (because of reserved BARs).
+ * This function can get the exact BAR used for self scratchpad from
+ * epf_ntb_bar[BAR_CONFIG].
+ *
+ * Please note the self scratchpad region and config region is combined to
+ * a single region and mapped using the same BAR. Also note HOST2's peer
+ * scratchpad is HOST1's self scratchpad.
+ */
+static int epf_ntb_config_sspad_bar_set(struct epf_ntb_epc *ntb_epc)
+{
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+	struct epf_ntb *ntb;
+	struct pci_epc *epc;
+	struct device *dev;
+	u8 func_no;
+	int ret;
+
+	ntb = ntb_epc->epf_ntb;
+	dev = &ntb->epf->dev;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb_epc->epf_bar[barno];
+
+	ret = pci_epc_set_bar(epc, func_no, epf_bar);
+	if (ret) {
+		dev_err(dev, "%s inft: Config/Status/SPAD BAR set failed\n",
+			pci_epc_interface_string(ntb_epc->type));
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_config_spad_bar_free() - Free the physical memory associated with
+ *   config + scratchpad region
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ * +-----------------+----+   +------------------+<-------+-----------------+
+ * |       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ * +-----------------+    +-->+------------------+<-------+-----------------+
+ * |       BAR2      |            Local Memory            |       BAR2      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR3      |                                    |       BAR3      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR4      |                                    |       BAR4      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR5      |                                    |       BAR5      |
+ * +-----------------+                                    +-----------------+
+ *   EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Free the Local Memory mentioned in the above diagram. After invoking this
+ * function, any of config + self scratchpad region of HOST1 or peer scratchpad
+ * region of HOST2 should not be accessed.
+ */
+static void epf_ntb_config_spad_bar_free(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+	struct epf_ntb_epc *ntb_epc;
+	enum pci_barno barno;
+	struct pci_epf *epf;
+
+	epf = ntb->epf;
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++) {
+		ntb_epc = ntb->epc[type];
+		barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+		if (ntb_epc->reg)
+			pci_epf_free_space(epf, ntb_epc->reg, barno, type);
+	}
+}
+
+/**
+ * epf_ntb_config_spad_bar_alloc() - Allocate memory for config + scratchpad
+ *   region
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       BAR0      |        |  CONFIG REGION   |        |       BAR0      |
+ * +-----------------+----+   +------------------+<-------+-----------------+
+ * |       BAR1      |    |   |SCRATCHPAD REGION |        |       BAR1      |
+ * +-----------------+    +-->+------------------+<-------+-----------------+
+ * |       BAR2      |            Local Memory            |       BAR2      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR3      |                                    |       BAR3      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR4      |                                    |       BAR4      |
+ * +-----------------+                                    +-----------------+
+ * |       BAR5      |                                    |       BAR5      |
+ * +-----------------+                                    +-----------------+
+ *   EP CONTROLLER 1                                        EP CONTROLLER 2
+ *
+ * Allocate the Local Memory mentioned in the above diagram. The size of
+ * CONFIG REGION is sizeof(struct epf_ntb_ctrl) and size of SCRATCHPAD REGION
+ * is obtained from "spad-count" configfs entry.
+ *
+ * The size of both config region and scratchpad region has to be aligned,
+ * since the scratchpad region will also be mapped as PEER SCRATCHPAD of
+ * other host using a separate BAR.
+ */
+static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb,
+					 enum pci_epc_interface_type type)
+{
+	const struct pci_epc_features *peer_epc_features, *epc_features;
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	size_t msix_table_size, pba_size, align;
+	enum pci_barno peer_barno, barno;
+	struct epf_ntb_ctrl *ctrl;
+	u32 spad_size, ctrl_size;
+	u64 size, peer_size;
+	struct pci_epf *epf;
+	struct device *dev;
+	bool msix_capable;
+	u32 spad_count;
+	void *base;
+
+	epf = ntb->epf;
+	dev = &epf->dev;
+	ntb_epc = ntb->epc[type];
+
+	epc_features = ntb_epc->epc_features;
+	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	size = epc_features->bar_fixed_size[barno];
+	align = epc_features->align;
+
+	peer_ntb_epc = ntb->epc[!type];
+	peer_epc_features = peer_ntb_epc->epc_features;
+	peer_barno = ntb_epc->epf_ntb_bar[BAR_PEER_SPAD];
+	peer_size = peer_epc_features->bar_fixed_size[peer_barno];
+
+	/* Check if epc_features is populated incorrectly */
+	if ((!IS_ALIGNED(size, align)))
+		return -EINVAL;
+
+	spad_count = ntb->spad_count;
+
+	ctrl_size = sizeof(struct epf_ntb_ctrl);
+	spad_size = spad_count * 4;
+
+	msix_capable = epc_features->msix_capable;
+	if (msix_capable) {
+		msix_table_size = PCI_MSIX_ENTRY_SIZE * ntb->db_count;
+		ctrl_size = ALIGN(ctrl_size, 8);
+		ntb_epc->msix_table_offset = ctrl_size;
+		ntb_epc->msix_bar = barno;
+		/* Align to QWORD or 8 Bytes */
+		pba_size = ALIGN(DIV_ROUND_UP(ntb->db_count, 8), 8);
+		ctrl_size = ctrl_size + msix_table_size + pba_size;
+	}
+
+	if (!align) {
+		ctrl_size = roundup_pow_of_two(ctrl_size);
+		spad_size = roundup_pow_of_two(spad_size);
+	} else {
+		ctrl_size = ALIGN(ctrl_size, align);
+		spad_size = ALIGN(spad_size, align);
+	}
+
+	if (peer_size) {
+		if (peer_size < spad_size)
+			spad_count = peer_size / 4;
+		spad_size = peer_size;
+	}
+
+	/*
+	 * In order to make sure SPAD offset is aligned to its size,
+	 * expand control region size to the size of SPAD if SPAD size
+	 * is greater than control region size.
+	 */
+	if (spad_size > ctrl_size)
+		ctrl_size = spad_size;
+
+	if (!size)
+		size = ctrl_size + spad_size;
+	else if (size < ctrl_size + spad_size)
+		return -EINVAL;
+
+	base = pci_epf_alloc_space(epf, size, barno, align, type);
+	if (!base) {
+		dev_err(dev, "%s intf: Config/Status/SPAD alloc region fail\n",
+			pci_epc_interface_string(type));
+		return -ENOMEM;
+	}
+
+	ntb_epc->reg = base;
+
+	ctrl = ntb_epc->reg;
+	ctrl->spad_offset = ctrl_size;
+	ctrl->spad_count = spad_count;
+	ctrl->num_mws = ntb->num_mws;
+	ctrl->db_entry_size = align ? align : 4;
+	ntb_epc->spad_size = spad_size;
+
+	return 0;
+}
+
+/**
+ * epf_ntb_config_spad_bar_alloc_interface() - Allocate memory for config +
+ *   scratchpad region for each of PRIMARY and SECONDARY interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * Wrapper for epf_ntb_config_spad_bar_alloc() which allocates memory for
+ * config + scratchpad region for a specific interface
+ */
+static int epf_ntb_config_spad_bar_alloc_interface(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+	struct device *dev;
+	int ret;
+
+	dev = &ntb->epf->dev;
+
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++) {
+		ret = epf_ntb_config_spad_bar_alloc(ntb, type);
+		if (ret) {
+			dev_err(dev, "%s intf: Config/SPAD BAR alloc failed\n",
+				pci_epc_interface_string(type));
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_free_peer_mem() - Free memory allocated in peers outbound address
+ *   space
+ * @ntb_epc: EPC associated with one of the HOST which holds peers outbound
+ *   address regions
+ *
+ * +-----------------+    +---->+----------------+-----------+-----------------+
+ * |       BAR0      |    |     |   Doorbell 1   +-----------> MSI|X ADDRESS 1 |
+ * +-----------------+    |     +----------------+           +-----------------+
+ * |       BAR1      |    |     |   Doorbell 2   +---------+ |                 |
+ * +-----------------+----+     +----------------+         | |                 |
+ * |       BAR2      |          |   Doorbell 3   +-------+ | +-----------------+
+ * +-----------------+----+     +----------------+       | +-> MSI|X ADDRESS 2 |
+ * |       BAR3      |    |     |   Doorbell 4   +-----+ |   +-----------------+
+ * +-----------------+    |     |----------------+     | |   |                 |
+ * |       BAR4      |    |     |                |     | |   +-----------------+
+ * +-----------------+    |     |      MW1       +---+ | +-->+ MSI|X ADDRESS 3||
+ * |       BAR5      |    |     |                |   | |     +-----------------+
+ * +-----------------+    +---->-----------------+   | |     |                 |
+ *   EP CONTROLLER 1            |                |   | |     +-----------------+
+ *                              |                |   | +---->+ MSI|X ADDRESS 4 |
+ *                              +----------------+   |       +-----------------+
+ *                      (A)      EP CONTROLLER 2     |       |                 |
+ *                                 (OB SPACE)        |       |                 |
+ *                                                   +------->      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ * Free memory allocated in EP CONTROLLER 2 (OB SPACE) in the above diagram.
+ * It'll free Doorbell 1, Doorbell 2, Doorbell 3, Doorbell 4, MW1 (and MW2, MW3,
+ * MW4).
+ */
+static void epf_ntb_free_peer_mem(struct epf_ntb_epc *ntb_epc)
+{
+	struct pci_epf_bar *epf_bar;
+	void __iomem *mw_addr;
+	phys_addr_t phys_addr;
+	enum epf_ntb_bar bar;
+	enum pci_barno barno;
+	struct pci_epc *epc;
+	size_t size;
+
+	epc = ntb_epc->epc;
+
+	for (bar = BAR_DB_MW1; bar < BAR_MW4; bar++) {
+		barno = ntb_epc->epf_ntb_bar[bar];
+		mw_addr = ntb_epc->mw_addr[barno];
+		epf_bar = &ntb_epc->epf_bar[barno];
+		phys_addr = epf_bar->phys_addr;
+		size = epf_bar->size;
+		if (mw_addr) {
+			pci_epc_mem_free_addr(epc, phys_addr, mw_addr, size);
+			ntb_epc->mw_addr[barno] = NULL;
+		}
+	}
+}
+
+/**
+ * epf_ntb_db_mw_bar_clear() - Clear doorbell and memory BAR
+ * @ntb_epc: EPC associated with one of the HOST which holds peer's outbound
+ *   address
+ *
+ * +-----------------+    +---->+----------------+-----------+-----------------+
+ * |       BAR0      |    |     |   Doorbell 1   +-----------> MSI|X ADDRESS 1 |
+ * +-----------------+    |     +----------------+           +-----------------+
+ * |       BAR1      |    |     |   Doorbell 2   +---------+ |                 |
+ * +-----------------+----+     +----------------+         | |                 |
+ * |       BAR2      |          |   Doorbell 3   +-------+ | +-----------------+
+ * +-----------------+----+     +----------------+       | +-> MSI|X ADDRESS 2 |
+ * |       BAR3      |    |     |   Doorbell 4   +-----+ |   +-----------------+
+ * +-----------------+    |     |----------------+     | |   |                 |
+ * |       BAR4      |    |     |                |     | |   +-----------------+
+ * +-----------------+    |     |      MW1       +---+ | +-->+ MSI|X ADDRESS 3||
+ * |       BAR5      |    |     |                |   | |     +-----------------+
+ * +-----------------+    +---->-----------------+   | |     |                 |
+ *   EP CONTROLLER 1            |                |   | |     +-----------------+
+ *                              |                |   | +---->+ MSI|X ADDRESS 4 |
+ *                              +----------------+   |       +-----------------+
+ *                      (A)      EP CONTROLLER 2     |       |                 |
+ *                                 (OB SPACE)        |       |                 |
+ *                                                   +------->      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ * Clear doorbell and memory BARs (remove inbound ATU configuration). In the above
+ * diagram it clears BAR2 TO BAR5 of EP CONTROLLER 1 (Doorbell BAR, MW1 BAR, MW2
+ * BAR, MW3 BAR and MW4 BAR).
+ */
+static void epf_ntb_db_mw_bar_clear(struct epf_ntb_epc *ntb_epc)
+{
+	struct pci_epf_bar *epf_bar;
+	enum epf_ntb_bar bar;
+	enum pci_barno barno;
+	struct pci_epc *epc;
+	u8 func_no;
+
+	epc = ntb_epc->epc;
+
+	func_no = ntb_epc->func_no;
+
+	for (bar = BAR_DB_MW1; bar < BAR_MW4; bar++) {
+		barno = ntb_epc->epf_ntb_bar[bar];
+		epf_bar = &ntb_epc->epf_bar[barno];
+		pci_epc_clear_bar(epc, func_no, epf_bar);
+	}
+}
+
+/**
+ * epf_ntb_db_mw_bar_cleanup() - Clear doorbell/memory BAR and free memory
+ *   allocated in peers outbound address space
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Wrapper for epf_ntb_db_mw_bar_clear() to clear HOST1's BAR and
+ * epf_ntb_free_peer_mem() which frees up HOST2 outbound memory.
+ */
+static void epf_ntb_db_mw_bar_cleanup(struct epf_ntb *ntb,
+				      enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+
+	ntb_epc = ntb->epc[type];
+	peer_ntb_epc = ntb->epc[!type];
+
+	epf_ntb_db_mw_bar_clear(ntb_epc);
+	epf_ntb_free_peer_mem(peer_ntb_epc);
+}
+
+/**
+ * epf_ntb_configure_interrupt() - Configure MSI/MSI-X capaiblity
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Configure MSI/MSI-X capability for each interface with number of
+ * interrupts equal to "db_count" configfs entry.
+ */
+static int epf_ntb_configure_interrupt(struct epf_ntb *ntb,
+				       enum pci_epc_interface_type type)
+{
+	const struct pci_epc_features *epc_features;
+	bool msix_capable, msi_capable;
+	struct epf_ntb_epc *ntb_epc;
+	struct pci_epc *epc;
+	struct device *dev;
+	u32 db_count;
+	u8 func_no;
+	int ret;
+
+	ntb_epc = ntb->epc[type];
+	dev = &ntb->epf->dev;
+
+	epc_features = ntb_epc->epc_features;
+	msix_capable = epc_features->msix_capable;
+	msi_capable = epc_features->msi_capable;
+
+	if (!(msix_capable || msi_capable)) {
+		dev_err(dev, "MSI or MSI-X is required for doorbell\n");
+		return -EINVAL;
+	}
+
+	func_no = ntb_epc->func_no;
+
+	db_count = ntb->db_count;
+	if (db_count > MAX_DB_COUNT) {
+		dev_err(dev, "DB count cannot be more than %d\n", MAX_DB_COUNT);
+		return -EINVAL;
+	}
+
+	ntb->db_count = db_count;
+	epc = ntb_epc->epc;
+
+	if (msi_capable) {
+		ret = pci_epc_set_msi(epc, func_no, db_count);
+		if (ret) {
+			dev_err(dev, "%s intf: MSI configuration failed\n",
+				pci_epc_interface_string(type));
+			return ret;
+		}
+	}
+
+	if (msix_capable) {
+		ret = pci_epc_set_msix(epc, func_no, db_count,
+				       ntb_epc->msix_bar,
+				       ntb_epc->msix_table_offset);
+		if (ret) {
+			dev_err(dev, "MSI configuration failed\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_alloc_peer_mem() - Allocate memory in peer's outbound address space
+ * @ntb_epc: EPC associated with one of the HOST whose BAR holds peer's outbound
+ *   address
+ * @bar: BAR of @ntb_epc in for which memory has to be allocated (could be
+ *   BAR_DB_MW1, BAR_MW2, BAR_MW3, BAR_MW4)
+ * @peer_ntb_epc: EPC associated with HOST whose outbound address space is
+ *   used by @ntb_epc
+ * @size: Size of the address region that has to be allocated in peers OB SPACE
+ *
+ *
+ * +-----------------+    +---->+----------------+-----------+-----------------+
+ * |       BAR0      |    |     |   Doorbell 1   +-----------> MSI|X ADDRESS 1 |
+ * +-----------------+    |     +----------------+           +-----------------+
+ * |       BAR1      |    |     |   Doorbell 2   +---------+ |                 |
+ * +-----------------+----+     +----------------+         | |                 |
+ * |       BAR2      |          |   Doorbell 3   +-------+ | +-----------------+
+ * +-----------------+----+     +----------------+       | +-> MSI|X ADDRESS 2 |
+ * |       BAR3      |    |     |   Doorbell 4   +-----+ |   +-----------------+
+ * +-----------------+    |     |----------------+     | |   |                 |
+ * |       BAR4      |    |     |                |     | |   +-----------------+
+ * +-----------------+    |     |      MW1       +---+ | +-->+ MSI|X ADDRESS 3||
+ * |       BAR5      |    |     |                |   | |     +-----------------+
+ * +-----------------+    +---->-----------------+   | |     |                 |
+ *   EP CONTROLLER 1            |                |   | |     +-----------------+
+ *                              |                |   | +---->+ MSI|X ADDRESS 4 |
+ *                              +----------------+   |       +-----------------+
+ *                      (A)      EP CONTROLLER 2     |       |                 |
+ *                                 (OB SPACE)        |       |                 |
+ *                                                   +------->      MW1        |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                   (B)     +-----------------+
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           |                 |
+ *                                                           +-----------------+
+ *                                                           PCI Address Space
+ *                                                           (Managed by HOST2)
+ *
+ * Allocate memory in OB space of EP CONTROLLER 2 in the above diagram. Allocate
+ * for Doorbell 1, Doorbell 2, Doorbell 3, Doorbell 4, MW1 (and MW2, MW3, MW4).
+ */
+static int epf_ntb_alloc_peer_mem(struct device *dev,
+				  struct epf_ntb_epc *ntb_epc,
+				  enum epf_ntb_bar bar,
+				  struct epf_ntb_epc *peer_ntb_epc,
+				  size_t size)
+{
+	const struct pci_epc_features *epc_features;
+	struct pci_epf_bar *epf_bar;
+	struct pci_epc *peer_epc;
+	phys_addr_t phys_addr;
+	void __iomem *mw_addr;
+	enum pci_barno barno;
+	size_t align;
+
+	epc_features = ntb_epc->epc_features;
+	align = epc_features->align;
+
+	if (size < 128)
+		size = 128;
+
+	if (align)
+		size = ALIGN(size, align);
+	else
+		size = roundup_pow_of_two(size);
+
+	peer_epc = peer_ntb_epc->epc;
+	mw_addr = pci_epc_mem_alloc_addr(peer_epc, &phys_addr, size);
+	if (!mw_addr) {
+		dev_err(dev, "%s intf: Failed to allocate OB address\n",
+			pci_epc_interface_string(peer_ntb_epc->type));
+		return -ENOMEM;
+	}
+
+	barno = ntb_epc->epf_ntb_bar[bar];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	ntb_epc->mw_addr[barno] = mw_addr;
+
+	epf_bar->phys_addr = phys_addr;
+	epf_bar->size = size;
+	epf_bar->barno = barno;
+	epf_bar->flags = PCI_BASE_ADDRESS_MEM_TYPE_32;
+
+	return 0;
+}
+
+/**
+ * epf_ntb_db_mw_bar_init() - Configure Doorbell and Memory window BARs
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Wrapper for epf_ntb_alloc_peer_mem() and pci_epc_set_bar() that allocates
+ * memory in OB address space of HOST2 and configures BAR of HOST1
+ */
+static int epf_ntb_db_mw_bar_init(struct epf_ntb *ntb,
+				  enum pci_epc_interface_type type)
+{
+	const struct pci_epc_features *epc_features;
+	struct epf_ntb_epc *peer_ntb_epc, *ntb_epc;
+	struct pci_epf_bar *epf_bar;
+	struct epf_ntb_ctrl *ctrl;
+	u32 num_mws, db_count;
+	enum epf_ntb_bar bar;
+	enum pci_barno barno;
+	struct pci_epc *epc;
+	struct device *dev;
+	size_t align;
+	int ret, i;
+	u8 func_no;
+	u64 size;
+
+	ntb_epc = ntb->epc[type];
+	peer_ntb_epc = ntb->epc[!type];
+
+	dev = &ntb->epf->dev;
+	epc_features = ntb_epc->epc_features;
+	align = epc_features->align;
+	func_no = ntb_epc->func_no;
+	epc = ntb_epc->epc;
+	num_mws = ntb->num_mws;
+	db_count = ntb->db_count;
+
+	for (bar = BAR_DB_MW1, i = 0; i < num_mws; bar++, i++) {
+		if (bar == BAR_DB_MW1) {
+			align = align ? align : 4;
+			size = db_count * align;
+			size = ALIGN(size, ntb->mws_size[i]);
+			ctrl = ntb_epc->reg;
+			ctrl->mw1_offset = size;
+			size += ntb->mws_size[i];
+		} else {
+			size = ntb->mws_size[i];
+		}
+
+		ret = epf_ntb_alloc_peer_mem(dev, ntb_epc, bar,
+					     peer_ntb_epc, size);
+		if (ret) {
+			dev_err(dev, "%s intf: DoorBell mem alloc failed\n",
+				pci_epc_interface_string(type));
+			goto err_alloc_peer_mem;
+		}
+
+		barno = ntb_epc->epf_ntb_bar[bar];
+		epf_bar = &ntb_epc->epf_bar[barno];
+
+		ret = pci_epc_set_bar(epc, func_no, epf_bar);
+		if (ret) {
+			dev_err(dev, "%s intf: DoorBell BAR set failed\n",
+				pci_epc_interface_string(type));
+			goto err_alloc_peer_mem;
+		}
+	}
+
+	return 0;
+
+err_alloc_peer_mem:
+	epf_ntb_db_mw_bar_cleanup(ntb, type);
+
+	return ret;
+}
+
+/**
+ * epf_ntb_epc_destroy_interface() - Cleanup NTB EPC interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Unbind NTB function device from EPC and relinquish reference to pci_epc
+ * for each of the interface.
+ */
+static void epf_ntb_epc_destroy_interface(struct epf_ntb *ntb,
+					  enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *ntb_epc;
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+
+	if (type < 0)
+		return;
+
+	epf = ntb->epf;
+	ntb_epc = ntb->epc[type];
+	if (!ntb_epc)
+		return;
+	epc = ntb_epc->epc;
+	pci_epc_remove_epf(epc, epf, type);
+	pci_epc_put(epc);
+}
+
+/**
+ * epf_ntb_epc_destroy() - Cleanup NTB EPC interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * Wrapper for epf_ntb_epc_destroy_interface() to cleanup all the NTB interfaces
+ */
+static void epf_ntb_epc_destroy(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++)
+		epf_ntb_epc_destroy_interface(ntb, type);
+}
+
+/**
+ * epf_ntb_epc_create_interface() - Create and initialize NTB EPC interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @epc: struct pci_epc to which a particular NTB interface should be associated
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Allocate memory for NTB EPC interface and initialize it.
+ */
+static int epf_ntb_epc_create_interface(struct epf_ntb *ntb,
+					struct pci_epc *epc,
+					enum pci_epc_interface_type type)
+{
+	const struct pci_epc_features *epc_features;
+	struct pci_epf_bar *epf_bar;
+	struct epf_ntb_epc *ntb_epc;
+	struct pci_epf *epf;
+	struct device *dev;
+	u8 func_no;
+
+	dev = &ntb->epf->dev;
+
+	ntb_epc = devm_kzalloc(dev, sizeof(*ntb_epc), GFP_KERNEL);
+	if (!ntb_epc)
+		return -ENOMEM;
+
+	epf = ntb->epf;
+	if (type == PRIMARY_INTERFACE) {
+		func_no = epf->func_no;
+		epf_bar = epf->bar;
+	} else {
+		func_no = epf->sec_epc_func_no;
+		epf_bar = epf->sec_epc_bar;
+	}
+
+	ntb_epc->linkup = false;
+	ntb_epc->epc = epc;
+	ntb_epc->func_no = func_no;
+	ntb_epc->type = type;
+	ntb_epc->epf_bar = epf_bar;
+	ntb_epc->epf_ntb = ntb;
+
+	epc_features = pci_epc_get_features(epc, func_no);
+	if (!epc_features)
+		return -EINVAL;
+	ntb_epc->epc_features = epc_features;
+
+	ntb->epc[type] = ntb_epc;
+
+	return 0;
+}
+
+/**
+ * epf_ntb_epc_create() - Create and initialize NTB EPC interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * Get a reference to EPC device and bind NTB function device to that EPC
+ * for each of the interface. It is also a wrapper to
+ * epf_ntb_epc_create_interface() to allocate memory for NTB EPC interface
+ * and initialize it
+ */
+static int epf_ntb_epc_create(struct epf_ntb *ntb)
+{
+	struct pci_epf *epf;
+	struct device *dev;
+	int ret;
+
+	epf = ntb->epf;
+	dev = &epf->dev;
+
+	ret = epf_ntb_epc_create_interface(ntb, epf->epc, PRIMARY_INTERFACE);
+	if (ret) {
+		dev_err(dev, "PRIMARY intf: Fail to create NTB EPC\n");
+		return ret;
+	}
+
+	ret = epf_ntb_epc_create_interface(ntb, epf->sec_epc,
+					   SECONDARY_INTERFACE);
+	if (ret) {
+		dev_err(dev, "SECONDARY intf: Fail to create NTB EPC\n");
+		goto err_epc_create;
+	}
+
+	return 0;
+
+err_epc_create:
+	epf_ntb_epc_destroy_interface(ntb, PRIMARY_INTERFACE);
+
+	return ret;
+}
+
+/**
+ * epf_ntb_init_epc_bar_interface() - Identify BARs to be used for each of
+ *   the NTB constructs (scratchpad region, doorbell, memorywindow)
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Identify the free BARs to be used for each of BAR_CONFIG, BAR_PEER_SPAD,
+ * BAR_DB_MW1, BAR_MW2, BAR_MW3 and BAR_MW4.
+ */
+static int epf_ntb_init_epc_bar_interface(struct epf_ntb *ntb,
+					  enum pci_epc_interface_type type)
+{
+	const struct pci_epc_features *epc_features;
+	struct epf_ntb_epc *ntb_epc;
+	enum pci_barno barno;
+	enum epf_ntb_bar bar;
+	struct device *dev;
+	u32 num_mws;
+	int i;
+
+	barno = BAR_0;
+	ntb_epc = ntb->epc[type];
+	num_mws = ntb->num_mws;
+	dev = &ntb->epf->dev;
+	epc_features = ntb_epc->epc_features;
+
+	/* These are required BARs which are mandatory for NTB functionality */
+	for (bar = BAR_CONFIG; bar <= BAR_DB_MW1; bar++, barno++) {
+		barno = pci_epc_get_next_free_bar(epc_features, barno);
+		if (barno < 0) {
+			dev_err(dev, "%s intf: Fail to get NTB function BAR\n",
+				pci_epc_interface_string(type));
+			return barno;
+		}
+		ntb_epc->epf_ntb_bar[bar] = barno;
+	}
+
+	/* These are optional BARs which don't impact NTB functionality */
+	for (bar = BAR_MW2, i = 1; i < num_mws; bar++, barno++, i++) {
+		barno = pci_epc_get_next_free_bar(epc_features, barno);
+		if (barno < 0) {
+			ntb->num_mws = i;
+			dev_dbg(dev, "BAR not available for > MW%d\n", i + 1);
+		}
+		ntb_epc->epf_ntb_bar[bar] = barno;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_init_epc_bar() - Identify BARs to be used for each of the NTB
+ * constructs (scratchpad region, doorbell, memorywindow)
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Wrapper to epf_ntb_init_epc_bar_interface() to identify the free BARs
+ * to be used for each of BAR_CONFIG, BAR_PEER_SPAD, BAR_DB_MW1, BAR_MW2,
+ * BAR_MW3 and BAR_MW4 for all the interfaces.
+ */
+static int epf_ntb_init_epc_bar(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+	struct device *dev;
+	int ret;
+
+	dev = &ntb->epf->dev;
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++) {
+		ret = epf_ntb_init_epc_bar_interface(ntb, type);
+		if (ret) {
+			dev_err(dev, "Fail to init EPC bar for %s interface\n",
+				pci_epc_interface_string(type));
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_epc_init_interface() - Initialize NTB interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Wrapper to initialize a particular EPC interface and start the workqueue
+ * to check for commands from host. This function will write to the
+ * EP controller HW for configuring it.
+ */
+static int epf_ntb_epc_init_interface(struct epf_ntb *ntb,
+				      enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *ntb_epc;
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+	struct device *dev;
+	u8 func_no;
+	int ret;
+
+	ntb_epc = ntb->epc[type];
+	epf = ntb->epf;
+	dev = &epf->dev;
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+
+	ret = epf_ntb_config_sspad_bar_set(ntb->epc[type]);
+	if (ret) {
+		dev_err(dev, "%s intf: Config/self SPAD BAR init failed\n",
+			pci_epc_interface_string(type));
+		return ret;
+	}
+
+	ret = epf_ntb_peer_spad_bar_set(ntb, type);
+	if (ret) {
+		dev_err(dev, "%s intf: Peer SPAD BAR init failed\n",
+			pci_epc_interface_string(type));
+		goto err_peer_spad_bar_init;
+	}
+
+	ret = epf_ntb_configure_interrupt(ntb, type);
+	if (ret) {
+		dev_err(dev, "%s intf: Interrupt configuration failed\n",
+			pci_epc_interface_string(type));
+		goto err_peer_spad_bar_init;
+	}
+
+	ret = epf_ntb_db_mw_bar_init(ntb, type);
+	if (ret) {
+		dev_err(dev, "%s intf: DB/MW BAR init failed\n",
+			pci_epc_interface_string(type));
+		goto err_db_mw_bar_init;
+	}
+
+	ret = pci_epc_write_header(epc, func_no, epf->header);
+	if (ret) {
+		dev_err(dev, "%s intf: Configuration header write failed\n",
+			pci_epc_interface_string(type));
+		goto err_write_header;
+	}
+
+	INIT_DELAYED_WORK(&ntb->epc[type]->cmd_handler, epf_ntb_cmd_handler);
+	queue_work(kpcintb_workqueue, &ntb->epc[type]->cmd_handler.work);
+
+	return 0;
+
+err_write_header:
+	epf_ntb_db_mw_bar_cleanup(ntb, type);
+
+err_db_mw_bar_init:
+	epf_ntb_peer_spad_bar_clear(ntb->epc[type]);
+
+err_peer_spad_bar_init:
+	epf_ntb_config_sspad_bar_clear(ntb->epc[type]);
+
+	return ret;
+}
+
+/**
+ * epf_ntb_epc_cleanup_interface() - Cleanup NTB interface
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ * @type: PRIMARY interface or SECONDARY interface
+ *
+ * Wrapper to cleanup a particular NTB interface.
+ */
+static void epf_ntb_epc_cleanup_interface(struct epf_ntb *ntb,
+					  enum pci_epc_interface_type type)
+{
+	struct epf_ntb_epc *ntb_epc;
+
+	if (type < 0)
+		return;
+
+	ntb_epc = ntb->epc[type];
+	cancel_delayed_work(&ntb_epc->cmd_handler);
+	epf_ntb_db_mw_bar_cleanup(ntb, type);
+	epf_ntb_peer_spad_bar_clear(ntb_epc);
+	epf_ntb_config_sspad_bar_clear(ntb_epc);
+}
+
+/**
+ * epf_ntb_epc_cleanup() - Cleanup all NTB interfaces
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * Wrapper to cleanup all NTB interfaces.
+ */
+static void epf_ntb_epc_cleanup(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++)
+		epf_ntb_epc_cleanup_interface(ntb, type);
+}
+
+/**
+ * epf_ntb_epc_init() - Initialize all NTB interfaces
+ * @ntb: NTB device that facilitates communication between HOST1 and HOST2
+ *
+ * Wrapper to initialize all NTB interface and start the workqueue
+ * to check for commands from host.
+ */
+static int epf_ntb_epc_init(struct epf_ntb *ntb)
+{
+	enum pci_epc_interface_type type;
+	struct device *dev;
+	int ret;
+
+	dev = &ntb->epf->dev;
+
+	for (type = PRIMARY_INTERFACE; type <= SECONDARY_INTERFACE; type++) {
+		ret = epf_ntb_epc_init_interface(ntb, type);
+		if (ret) {
+			dev_err(dev, "%s intf: Failed to initialize\n",
+				pci_epc_interface_string(type));
+			goto err_init_type;
+		}
+	}
+
+	return 0;
+
+err_init_type:
+	epf_ntb_epc_cleanup_interface(ntb, type - 1);
+
+	return ret;
+}
+
+/**
+ * epf_ntb_bind() - Initialize endpoint controller to provide NTB functionality
+ * @epf: NTB endpoint function device
+ *
+ * Initialize both the endpoint controllers associated with NTB function device.
+ * Invoked when a primary interface or secondary interface is bound to EPC
+ * device. This function will succeed only when EPC is bound to both the
+ * interfaces.
+ */
+static int epf_ntb_bind(struct pci_epf *epf)
+{
+	struct epf_ntb *ntb = epf_get_drvdata(epf);
+	struct device *dev = &epf->dev;
+	int ret;
+
+	if (!epf->epc) {
+		dev_dbg(dev, "PRIMARY EPC interface not yet bound\n");
+		return 0;
+	}
+
+	if (!epf->sec_epc) {
+		dev_dbg(dev, "SECONDARY EPC interface not yet bound\n");
+		return 0;
+	}
+
+	ret = epf_ntb_epc_create(ntb);
+	if (ret) {
+		dev_err(dev, "Failed to create NTB EPC\n");
+		return ret;
+	}
+
+	ret = epf_ntb_init_epc_bar(ntb);
+	if (ret) {
+		dev_err(dev, "Failed to create NTB EPC\n");
+		goto err_bar_init;
+	}
+
+	ret = epf_ntb_config_spad_bar_alloc_interface(ntb);
+	if (ret) {
+		dev_err(dev, "Failed to allocate BAR memory\n");
+		goto err_bar_alloc;
+	}
+
+	ret = epf_ntb_epc_init(ntb);
+	if (ret) {
+		dev_err(dev, "Failed to initialize EPC\n");
+		goto err_bar_alloc;
+	}
+
+	epf_set_drvdata(epf, ntb);
+
+	return 0;
+
+err_bar_alloc:
+	epf_ntb_config_spad_bar_free(ntb);
+
+err_bar_init:
+	epf_ntb_epc_destroy(ntb);
+
+	return ret;
+}
+
+/**
+ * epf_ntb_unbind() - Cleanup the initialization from epf_ntb_bind()
+ * @epf: NTB endpoint function device
+ *
+ * Cleanup the initialization from epf_ntb_bind()
+ */
+static void epf_ntb_unbind(struct pci_epf *epf)
+{
+	struct epf_ntb *ntb = epf_get_drvdata(epf);
+
+	epf_ntb_epc_cleanup(ntb);
+	epf_ntb_config_spad_bar_free(ntb);
+	epf_ntb_epc_destroy(ntb);
+}
+
+#define EPF_NTB_R(_name)						\
+static ssize_t epf_ntb_##_name##_show(struct config_item *item,		\
+				      char *page)			\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+									\
+	return sprintf(page, "%d\n", ntb->_name);			\
+}
+
+#define EPF_NTB_W(_name)						\
+static ssize_t epf_ntb_##_name##_store(struct config_item *item,	\
+				       const char *page, size_t len)	\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	u32 val;							\
+	int ret;							\
+									\
+	ret = kstrtou32(page, 0, &val);					\
+	if (ret)							\
+		return ret;						\
+									\
+	ntb->_name = val;						\
+									\
+	return len;							\
+}
+
+#define EPF_NTB_MW_R(_name)						\
+static ssize_t epf_ntb_##_name##_show(struct config_item *item,		\
+				      char *page)			\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	int win_no;							\
+									\
+	sscanf(#_name, "mw%d", &win_no);				\
+									\
+	return sprintf(page, "%lld\n", ntb->mws_size[win_no - 1]);	\
+}
+
+#define EPF_NTB_MW_W(_name)						\
+static ssize_t epf_ntb_##_name##_store(struct config_item *item,	\
+				       const char *page, size_t len)	\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	struct device *dev = &ntb->epf->dev;				\
+	int win_no;							\
+	u64 val;							\
+	int ret;							\
+									\
+	ret = kstrtou64(page, 0, &val);					\
+	if (ret)							\
+		return ret;						\
+									\
+	if (sscanf(#_name, "mw%d", &win_no) != 1)			\
+		return -EINVAL;						\
+									\
+	if (ntb->num_mws < win_no) {					\
+		dev_err(dev, "Invalid num_nws: %d value\n", ntb->num_mws); \
+		return -EINVAL;						\
+	}								\
+									\
+	ntb->mws_size[win_no - 1] = val;				\
+									\
+	return len;							\
+}
+
+static ssize_t epf_ntb_num_mws_store(struct config_item *item,
+				     const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item);
+	struct epf_ntb *ntb = to_epf_ntb(group);
+	u32 val;
+	int ret;
+
+	ret = kstrtou32(page, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > MAX_MW)
+		return -EINVAL;
+
+	ntb->num_mws = val;
+
+	return len;
+}
+
+EPF_NTB_R(spad_count)
+EPF_NTB_W(spad_count)
+EPF_NTB_R(db_count)
+EPF_NTB_W(db_count)
+EPF_NTB_R(num_mws)
+EPF_NTB_MW_R(mw1)
+EPF_NTB_MW_W(mw1)
+EPF_NTB_MW_R(mw2)
+EPF_NTB_MW_W(mw2)
+EPF_NTB_MW_R(mw3)
+EPF_NTB_MW_W(mw3)
+EPF_NTB_MW_R(mw4)
+EPF_NTB_MW_W(mw4)
+
+CONFIGFS_ATTR(epf_ntb_, spad_count);
+CONFIGFS_ATTR(epf_ntb_, db_count);
+CONFIGFS_ATTR(epf_ntb_, num_mws);
+CONFIGFS_ATTR(epf_ntb_, mw1);
+CONFIGFS_ATTR(epf_ntb_, mw2);
+CONFIGFS_ATTR(epf_ntb_, mw3);
+CONFIGFS_ATTR(epf_ntb_, mw4);
+
+static struct configfs_attribute *epf_ntb_attrs[] = {
+	&epf_ntb_attr_spad_count,
+	&epf_ntb_attr_db_count,
+	&epf_ntb_attr_num_mws,
+	&epf_ntb_attr_mw1,
+	&epf_ntb_attr_mw2,
+	&epf_ntb_attr_mw3,
+	&epf_ntb_attr_mw4,
+	NULL,
+};
+
+static const struct config_item_type ntb_group_type = {
+	.ct_attrs	= epf_ntb_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/**
+ * epf_ntb_add_cfs() - Add configfs directory specific to NTB
+ * @epf: NTB endpoint function device
+ *
+ * Add configfs directory specific to NTB. This directory will hold
+ * NTB specific properties like db_count, spad_count, num_mws etc.,
+ */
+static struct config_group *epf_ntb_add_cfs(struct pci_epf *epf,
+					    struct config_group *group)
+{
+	struct epf_ntb *ntb = epf_get_drvdata(epf);
+	struct config_group *ntb_group = &ntb->group;
+	struct device *dev = &epf->dev;
+
+	config_group_init_type_name(ntb_group, dev_name(dev), &ntb_group_type);
+
+	return ntb_group;
+}
+
+/**
+ * epf_ntb_probe() - Probe NTB function driver
+ * @epf: NTB endpoint function device
+ *
+ * Probe NTB function driver when endpoint function bus detects a NTB
+ * endpoint function.
+ */
+static int epf_ntb_probe(struct pci_epf *epf)
+{
+	struct epf_ntb *ntb;
+	struct device *dev;
+
+	dev = &epf->dev;
+
+	ntb = devm_kzalloc(dev, sizeof(*ntb), GFP_KERNEL);
+	if (!ntb)
+		return -ENOMEM;
+
+	epf->header = &epf_ntb_header;
+	ntb->epf = epf;
+	epf_set_drvdata(epf, ntb);
+
+	return 0;
+}
+
+static struct pci_epf_ops epf_ntb_ops = {
+	.bind	= epf_ntb_bind,
+	.unbind	= epf_ntb_unbind,
+	.add_cfs = epf_ntb_add_cfs,
+};
+
+static const struct pci_epf_device_id epf_ntb_ids[] = {
+	{
+		.name = "pci_epf_ntb",
+	},
+	{},
+};
+
+static struct pci_epf_driver epf_ntb_driver = {
+	.driver.name	= "pci_epf_ntb",
+	.probe		= epf_ntb_probe,
+	.id_table	= epf_ntb_ids,
+	.ops		= &epf_ntb_ops,
+	.owner		= THIS_MODULE,
+};
+
+static int __init epf_ntb_init(void)
+{
+	int ret;
+
+	kpcintb_workqueue = alloc_workqueue("kpcintb", WQ_MEM_RECLAIM |
+					    WQ_HIGHPRI, 0);
+	ret = pci_epf_register_driver(&epf_ntb_driver);
+	if (ret) {
+		destroy_workqueue(kpcintb_workqueue);
+		pr_err("Failed to register pci epf ntb driver --> %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(epf_ntb_init);
+
+static void __exit epf_ntb_exit(void)
+{
+	pci_epf_unregister_driver(&epf_ntb_driver);
+	destroy_workqueue(kpcintb_workqueue);
+}
+module_exit(epf_ntb_exit);
+
+MODULE_DESCRIPTION("PCI EPF NTB DRIVER");
+MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index e4e51d884553..c0ac4e9cbe72 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -619,7 +619,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
 
 		if (epf_test->reg[bar]) {
 			pci_epc_clear_bar(epc, epf->func_no, epf_bar);
-			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			pci_epf_free_space(epf, epf_test->reg[bar], bar,
+					   PRIMARY_INTERFACE);
 		}
 	}
 }
@@ -651,7 +652,8 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
 
 		ret = pci_epc_set_bar(epc, epf->func_no, epf_bar);
 		if (ret) {
-			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			pci_epf_free_space(epf, epf_test->reg[bar], bar,
+					   PRIMARY_INTERFACE);
 			dev_err(dev, "Failed to set BAR%d\n", bar);
 			if (bar == test_reg_bar)
 				return ret;
@@ -771,7 +773,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 	}
 
 	base = pci_epf_alloc_space(epf, test_reg_size, test_reg_bar,
-				   epc_features->align);
+				   epc_features->align, PRIMARY_INTERFACE);
 	if (!base) {
 		dev_err(dev, "Failed to allocated register space\n");
 		return -ENOMEM;
@@ -789,7 +791,8 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 			continue;
 
 		base = pci_epf_alloc_space(epf, bar_size[bar], bar,
-					   epc_features->align);
+					   epc_features->align,
+					   PRIMARY_INTERFACE);
 		if (!base)
 			dev_err(dev, "Failed to allocate space for BAR%d\n",
 				bar);
@@ -834,6 +837,8 @@ static int pci_epf_test_bind(struct pci_epf *epf)
 		linkup_notifier = epc_features->linkup_notifier;
 		core_init_notifier = epc_features->core_init_notifier;
 		test_reg_bar = pci_epc_get_first_free_bar(epc_features);
+		if (test_reg_bar < 0)
+			return -EINVAL;
 		pci_epf_configure_bar(epf, epc_features);
 	}
 
diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 3710adf51912..f3a8b833b479 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -21,6 +21,9 @@ static struct config_group *controllers_group;
 
 struct pci_epf_group {
 	struct config_group group;
+	struct config_group primary_epc_group;
+	struct config_group secondary_epc_group;
+	struct delayed_work cfs_work;
 	struct pci_epf *epf;
 	int index;
 };
@@ -41,6 +44,127 @@ static inline struct pci_epc_group *to_pci_epc_group(struct config_item *item)
 	return container_of(to_config_group(item), struct pci_epc_group, group);
 }
 
+static int pci_secondary_epc_epf_link(struct config_item *epf_item,
+				      struct config_item *epc_item)
+{
+	int ret;
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item->ci_parent);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+	struct pci_epc *epc = epc_group->epc;
+	struct pci_epf *epf = epf_group->epf;
+
+	ret = pci_epc_add_epf(epc, epf, SECONDARY_INTERFACE);
+	if (ret)
+		return ret;
+
+	ret = pci_epf_bind(epf);
+	if (ret) {
+		pci_epc_remove_epf(epc, epf, SECONDARY_INTERFACE);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void pci_secondary_epc_epf_unlink(struct config_item *epc_item,
+					 struct config_item *epf_item)
+{
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item->ci_parent);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+
+	WARN_ON_ONCE(epc_group->start);
+
+	epc = epc_group->epc;
+	epf = epf_group->epf;
+	pci_epf_unbind(epf);
+	pci_epc_remove_epf(epc, epf, SECONDARY_INTERFACE);
+}
+
+static struct configfs_item_operations pci_secondary_epc_item_ops = {
+	.allow_link	= pci_secondary_epc_epf_link,
+	.drop_link	= pci_secondary_epc_epf_unlink,
+};
+
+static const struct config_item_type pci_secondary_epc_type = {
+	.ct_item_ops	= &pci_secondary_epc_item_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group
+*pci_ep_cfs_add_secondary_group(struct pci_epf_group *epf_group)
+{
+	struct config_group *secondary_epc_group;
+
+	secondary_epc_group = &epf_group->secondary_epc_group;
+	config_group_init_type_name(secondary_epc_group, "secondary",
+				    &pci_secondary_epc_type);
+	configfs_register_group(&epf_group->group, secondary_epc_group);
+
+	return secondary_epc_group;
+}
+
+static int pci_primary_epc_epf_link(struct config_item *epf_item,
+				    struct config_item *epc_item)
+{
+	int ret;
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item->ci_parent);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+	struct pci_epc *epc = epc_group->epc;
+	struct pci_epf *epf = epf_group->epf;
+
+	ret = pci_epc_add_epf(epc, epf, PRIMARY_INTERFACE);
+	if (ret)
+		return ret;
+
+	ret = pci_epf_bind(epf);
+	if (ret) {
+		pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void pci_primary_epc_epf_unlink(struct config_item *epc_item,
+				       struct config_item *epf_item)
+{
+	struct pci_epf_group *epf_group = to_pci_epf_group(epf_item->ci_parent);
+	struct pci_epc_group *epc_group = to_pci_epc_group(epc_item);
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+
+	WARN_ON_ONCE(epc_group->start);
+
+	epc = epc_group->epc;
+	epf = epf_group->epf;
+	pci_epf_unbind(epf);
+	pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
+}
+
+static struct configfs_item_operations pci_primary_epc_item_ops = {
+	.allow_link	= pci_primary_epc_epf_link,
+	.drop_link	= pci_primary_epc_epf_unlink,
+};
+
+static const struct config_item_type pci_primary_epc_type = {
+	.ct_item_ops	= &pci_primary_epc_item_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group
+*pci_ep_cfs_add_primary_group(struct pci_epf_group *epf_group)
+{
+	struct config_group *primary_epc_group = &epf_group->primary_epc_group;
+
+	config_group_init_type_name(primary_epc_group, "primary",
+				    &pci_primary_epc_type);
+	configfs_register_group(&epf_group->group, primary_epc_group);
+
+	return primary_epc_group;
+}
+
 static ssize_t pci_epc_start_store(struct config_item *item, const char *page,
 				   size_t len)
 {
@@ -94,13 +218,13 @@ static int pci_epc_epf_link(struct config_item *epc_item,
 	struct pci_epc *epc = epc_group->epc;
 	struct pci_epf *epf = epf_group->epf;
 
-	ret = pci_epc_add_epf(epc, epf);
+	ret = pci_epc_add_epf(epc, epf, PRIMARY_INTERFACE);
 	if (ret)
 		return ret;
 
 	ret = pci_epf_bind(epf);
 	if (ret) {
-		pci_epc_remove_epf(epc, epf);
+		pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
 		return ret;
 	}
 
@@ -120,7 +244,7 @@ static void pci_epc_epf_unlink(struct config_item *epc_item,
 	epc = epc_group->epc;
 	epf = epf_group->epf;
 	pci_epf_unbind(epf);
-	pci_epc_remove_epf(epc, epf);
+	pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
 }
 
 static struct configfs_item_operations pci_epc_item_ops = {
@@ -366,12 +490,53 @@ static struct configfs_item_operations pci_epf_ops = {
 	.release		= pci_epf_release,
 };
 
+static struct config_group *pci_epf_type_make(struct config_group *group,
+					      const char *name)
+{
+	struct pci_epf_group *epf_group = to_pci_epf_group(&group->cg_item);
+	struct config_group *epf_type_group;
+
+	epf_type_group = pci_epf_type_add_cfs(epf_group->epf, group);
+	return epf_type_group;
+}
+
+static void pci_epf_type_drop(struct config_group *group,
+			      struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations pci_epf_type_group_ops = {
+	.make_group     = &pci_epf_type_make,
+	.drop_item      = &pci_epf_type_drop,
+};
+
 static const struct config_item_type pci_epf_type = {
+	.ct_group_ops	= &pci_epf_type_group_ops,
 	.ct_item_ops	= &pci_epf_ops,
 	.ct_attrs	= pci_epf_attrs,
 	.ct_owner	= THIS_MODULE,
 };
 
+static void pci_epf_cfs_work(struct work_struct *work)
+{
+	struct pci_epf_group *epf_group;
+	struct config_group *group;
+
+	epf_group = container_of(work, struct pci_epf_group, cfs_work.work);
+	group = pci_ep_cfs_add_primary_group(epf_group);
+	if (IS_ERR(group)) {
+		pr_err("failed to create 'primary' EPC interface\n");
+		return;
+	}
+
+	group = pci_ep_cfs_add_secondary_group(epf_group);
+	if (IS_ERR(group)) {
+		pr_err("failed to create 'secondary' EPC interface\n");
+		return;
+	}
+}
+
 static struct config_group *pci_epf_make(struct config_group *group,
 					 const char *name)
 {
@@ -410,10 +575,15 @@ static struct config_group *pci_epf_make(struct config_group *group,
 		goto free_name;
 	}
 
+	epf->group = &epf_group->group;
 	epf_group->epf = epf;
 
 	kfree(epf_name);
 
+	INIT_DELAYED_WORK(&epf_group->cfs_work, pci_epf_cfs_work);
+	queue_delayed_work(system_wq, &epf_group->cfs_work,
+			   msecs_to_jiffies(1));
+
 	return &epf_group->group;
 
 free_name:
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index cadd3db0cbb0..cc8f9eb2b177 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -87,24 +87,50 @@ EXPORT_SYMBOL_GPL(pci_epc_get);
  * pci_epc_get_first_free_bar() - helper to get first unreserved BAR
  * @epc_features: pci_epc_features structure that holds the reserved bar bitmap
  *
- * Invoke to get the first unreserved BAR that can be used for endpoint
+ * Invoke to get the first unreserved BAR that can be used by the endpoint
  * function. For any incorrect value in reserved_bar return '0'.
  */
-unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
-					*epc_features)
+enum pci_barno
+pci_epc_get_first_free_bar(const struct pci_epc_features *epc_features)
 {
-	int free_bar;
+	return pci_epc_get_next_free_bar(epc_features, BAR_0);
+}
+EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
+
+/**
+ * pci_epc_get_next_free_bar() - helper to get unreserved BAR starting from @bar
+ * @epc_features: pci_epc_features structure that holds the reserved bar bitmap
+ * @bar: the starting BAR number from where unreserved BAR should be searched
+ *
+ * Invoke to get the next unreserved BAR starting from @bar that can be used
+ * for endpoint function. For any incorrect value in reserved_bar return '0'.
+ */
+enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features
+					 *epc_features, enum pci_barno bar)
+{
+	unsigned long free_bar;
 
 	if (!epc_features)
-		return 0;
+		return BAR_0;
+
+	/* If 'bar - 1' is a 64-bit BAR, move to the next BAR */
+	if ((epc_features->bar_fixed_64bit << 1) & 1 << bar)
+		bar++;
+
+	/* Find if the reserved BAR is also a 64-bit BAR */
+	free_bar = epc_features->reserved_bar & epc_features->bar_fixed_64bit;
 
-	free_bar = ffz(epc_features->reserved_bar);
+	/* Set the adjacent bit if the reserved BAR is also a 64-bit BAR */
+	free_bar <<= 1;
+	free_bar |= epc_features->reserved_bar;
+
+	free_bar = find_next_zero_bit(&free_bar, 6, bar);
 	if (free_bar > 5)
-		return 0;
+		return NO_BAR;
 
 	return free_bar;
 }
-EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
+EXPORT_SYMBOL_GPL(pci_epc_get_next_free_bar);
 
 /**
  * pci_epc_get_features() - get the features supported by EPC
@@ -205,6 +231,47 @@ int pci_epc_raise_irq(struct pci_epc *epc, u8 func_no,
 EXPORT_SYMBOL_GPL(pci_epc_raise_irq);
 
 /**
+ * pci_epc_map_msi_irq() - Map physical address to MSI address and return
+ *                         MSI data
+ * @epc: the EPC device which has the MSI capability
+ * @func_no: the physical endpoint function number in the EPC device
+ * @phys_addr: the physical address of the outbound region
+ * @interrupt_num: the MSI interrupt number
+ * @entry_size: Size of Outbound address region for each interrupt
+ * @msi_data: the data that should be written in order to raise MSI interrupt
+ *            with interrupt number as 'interrupt num'
+ * @msi_addr_offset: Offset of MSI address from the aligned outbound address
+ *                   to which the MSI address is mapped
+ *
+ * Invoke to map physical address to MSI address and return MSI data. The
+ * physical address should be an address in the outbound region. This is
+ * required to implement doorbell functionality of NTB wherein EPC on either
+ * side of the interface (primary and secondary) can directly write to the
+ * physical address (in outbound region) of the other interface to ring
+ * doorbell.
+ */
+int pci_epc_map_msi_irq(struct pci_epc *epc, u8 func_no, phys_addr_t phys_addr,
+			u8 interrupt_num, u32 entry_size, u32 *msi_data,
+			u32 *msi_addr_offset)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(epc))
+		return -EINVAL;
+
+	if (!epc->ops->map_msi_irq)
+		return -EINVAL;
+
+	mutex_lock(&epc->lock);
+	ret = epc->ops->map_msi_irq(epc, func_no, phys_addr, interrupt_num,
+				    entry_size, msi_data, msi_addr_offset);
+	mutex_unlock(&epc->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pci_epc_map_msi_irq);
+
+/**
  * pci_epc_get_msi() - get the number of MSI interrupt numbers allocated
  * @epc: the EPC device to which MSI interrupts was requested
  * @func_no: the endpoint function number in the EPC device
@@ -467,21 +534,28 @@ EXPORT_SYMBOL_GPL(pci_epc_write_header);
  * pci_epc_add_epf() - bind PCI endpoint function to an endpoint controller
  * @epc: the EPC device to which the endpoint function should be added
  * @epf: the endpoint function to be added
+ * @type: Identifies if the EPC is connected to the primary or secondary
+ *        interface of EPF
  *
  * A PCI endpoint device can have one or more functions. In the case of PCIe,
  * the specification allows up to 8 PCIe endpoint functions. Invoke
  * pci_epc_add_epf() to add a PCI endpoint function to an endpoint controller.
  */
-int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
+int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
+		    enum pci_epc_interface_type type)
 {
+	struct list_head *list;
 	u32 func_no;
 	int ret = 0;
 
-	if (epf->epc)
+	if (IS_ERR_OR_NULL(epc))
+		return -EINVAL;
+
+	if (type == PRIMARY_INTERFACE && epf->epc)
 		return -EBUSY;
 
-	if (IS_ERR(epc))
-		return -EINVAL;
+	if (type == SECONDARY_INTERFACE && epf->sec_epc)
+		return -EBUSY;
 
 	mutex_lock(&epc->lock);
 	func_no = find_first_zero_bit(&epc->function_num_map,
@@ -498,11 +572,17 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 	}
 
 	set_bit(func_no, &epc->function_num_map);
-	epf->func_no = func_no;
-	epf->epc = epc;
-
-	list_add_tail(&epf->list, &epc->pci_epf);
+	if (type == PRIMARY_INTERFACE) {
+		epf->func_no = func_no;
+		epf->epc = epc;
+		list = &epf->list;
+	} else {
+		epf->sec_epc_func_no = func_no;
+		epf->sec_epc = epc;
+		list = &epf->sec_epc_list;
+	}
 
+	list_add_tail(list, &epc->pci_epf);
 ret:
 	mutex_unlock(&epc->lock);
 
@@ -517,14 +597,26 @@ EXPORT_SYMBOL_GPL(pci_epc_add_epf);
  *
  * Invoke to remove PCI endpoint function from the endpoint controller.
  */
-void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf)
+void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
+			enum pci_epc_interface_type type)
 {
+	struct list_head *list;
+	u32 func_no = 0;
+
 	if (!epc || IS_ERR(epc) || !epf)
 		return;
 
+	if (type == PRIMARY_INTERFACE) {
+		func_no = epf->func_no;
+		list = &epf->list;
+	} else {
+		func_no = epf->sec_epc_func_no;
+		list = &epf->sec_epc_list;
+	}
+
 	mutex_lock(&epc->lock);
-	clear_bit(epf->func_no, &epc->function_num_map);
-	list_del(&epf->list);
+	clear_bit(func_no, &epc->function_num_map);
+	list_del(list);
 	epf->epc = NULL;
 	mutex_unlock(&epc->lock);
 }
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index c977cf9dce56..7646c8660d42 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -21,6 +21,38 @@ static struct bus_type pci_epf_bus_type;
 static const struct device_type pci_epf_type;
 
 /**
+ * pci_epf_type_add_cfs() - Help function drivers to expose function specific
+ *                          attributes in configfs
+ * @epf: the EPF device that has to be configured using configfs
+ * @group: the parent configfs group (corresponding to entries in
+ *         pci_epf_device_id)
+ *
+ * Invoke to expose function specific attributes in configfs. If the function
+ * driver does not have anything to expose (attributes configured by user),
+ * return NULL.
+ */
+struct config_group *pci_epf_type_add_cfs(struct pci_epf *epf,
+					  struct config_group *group)
+{
+	struct config_group *epf_type_group;
+
+	if (!epf->driver) {
+		dev_err(&epf->dev, "epf device not bound to driver\n");
+		return NULL;
+	}
+
+	if (!epf->driver->ops->add_cfs)
+		return NULL;
+
+	mutex_lock(&epf->lock);
+	epf_type_group = epf->driver->ops->add_cfs(epf, group);
+	mutex_unlock(&epf->lock);
+
+	return epf_type_group;
+}
+EXPORT_SYMBOL_GPL(pci_epf_type_add_cfs);
+
+/**
  * pci_epf_unbind() - Notify the function driver that the binding between the
  *		      EPF device and EPC device has been lost
  * @epf: the EPF device which has lost the binding with the EPC device
@@ -74,24 +106,37 @@ EXPORT_SYMBOL_GPL(pci_epf_bind);
  * @epf: the EPF device from whom to free the memory
  * @addr: the virtual address of the PCI EPF register space
  * @bar: the BAR number corresponding to the register space
+ * @type: Identifies if the allocated space is for primary EPC or secondary EPC
  *
  * Invoke to free the allocated PCI EPF register space.
  */
-void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar)
+void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
+			enum pci_epc_interface_type type)
 {
 	struct device *dev = epf->epc->dev.parent;
+	struct pci_epf_bar *epf_bar;
+	struct pci_epc *epc;
 
 	if (!addr)
 		return;
 
-	dma_free_coherent(dev, epf->bar[bar].size, addr,
-			  epf->bar[bar].phys_addr);
+	if (type == PRIMARY_INTERFACE) {
+		epc = epf->epc;
+		epf_bar = epf->bar;
+	} else {
+		epc = epf->sec_epc;
+		epf_bar = epf->sec_epc_bar;
+	}
 
-	epf->bar[bar].phys_addr = 0;
-	epf->bar[bar].addr = NULL;
-	epf->bar[bar].size = 0;
-	epf->bar[bar].barno = 0;
-	epf->bar[bar].flags = 0;
+	dev = epc->dev.parent;
+	dma_free_coherent(dev, epf_bar[bar].size, addr,
+			  epf_bar[bar].phys_addr);
+
+	epf_bar[bar].phys_addr = 0;
+	epf_bar[bar].addr = NULL;
+	epf_bar[bar].size = 0;
+	epf_bar[bar].barno = 0;
+	epf_bar[bar].flags = 0;
 }
 EXPORT_SYMBOL_GPL(pci_epf_free_space);
 
@@ -101,15 +146,18 @@ EXPORT_SYMBOL_GPL(pci_epf_free_space);
  * @size: the size of the memory that has to be allocated
  * @bar: the BAR number corresponding to the allocated register space
  * @align: alignment size for the allocation region
+ * @type: Identifies if the allocation is for primary EPC or secondary EPC
  *
  * Invoke to allocate memory for the PCI EPF register space.
  */
 void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
-			  size_t align)
+			  size_t align, enum pci_epc_interface_type type)
 {
-	void *space;
-	struct device *dev = epf->epc->dev.parent;
+	struct pci_epf_bar *epf_bar;
 	dma_addr_t phys_addr;
+	struct pci_epc *epc;
+	struct device *dev;
+	void *space;
 
 	if (size < 128)
 		size = 128;
@@ -119,17 +167,26 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 	else
 		size = roundup_pow_of_two(size);
 
+	if (type == PRIMARY_INTERFACE) {
+		epc = epf->epc;
+		epf_bar = epf->bar;
+	} else {
+		epc = epf->sec_epc;
+		epf_bar = epf->sec_epc_bar;
+	}
+
+	dev = epc->dev.parent;
 	space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL);
 	if (!space) {
 		dev_err(dev, "failed to allocate mem space\n");
 		return NULL;
 	}
 
-	epf->bar[bar].phys_addr = phys_addr;
-	epf->bar[bar].addr = space;
-	epf->bar[bar].size = size;
-	epf->bar[bar].barno = bar;
-	epf->bar[bar].flags |= upper_32_bits(size) ?
+	epf_bar[bar].phys_addr = phys_addr;
+	epf_bar[bar].addr = space;
+	epf_bar[bar].size = size;
+	epf_bar[bar].barno = bar;
+	epf_bar[bar].flags |= upper_32_bits(size) ?
 				PCI_BASE_ADDRESS_MEM_TYPE_64 :
 				PCI_BASE_ADDRESS_MEM_TYPE_32;
 
@@ -282,22 +339,6 @@ struct pci_epf *pci_epf_create(const char *name)
 }
 EXPORT_SYMBOL_GPL(pci_epf_create);
 
-const struct pci_epf_device_id *
-pci_epf_match_device(const struct pci_epf_device_id *id, struct pci_epf *epf)
-{
-	if (!id || !epf)
-		return NULL;
-
-	while (*id->name) {
-		if (strcmp(epf->name, id->name) == 0)
-			return id;
-		id++;
-	}
-
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(pci_epf_match_device);
-
 static void pci_epf_dev_release(struct device *dev)
 {
 	struct pci_epf *epf = to_pci_epf(dev);