Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 5412 insertions, 0 deletions

diff --git a/drivers/pci/endpoint/functions/Kconfig b/drivers/pci/endpoint/functions/Kconfig
new file mode 100644
index 0000000000..0c9cea0698
--- /dev/null
+++ b/drivers/pci/endpoint/functions/Kconfig
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# PCI Endpoint Functions
+#
+
+config PCI_EPF_TEST
+	tristate "PCI Endpoint Test driver"
+	depends on PCI_ENDPOINT
+	select CRC32
+	help
+	   Enable this configuration option to enable the test driver
+	   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.
+
+config PCI_EPF_VNTB
+	tristate "PCI Endpoint Virtual NTB driver"
+	depends on PCI_ENDPOINT
+	depends on NTB
+	select CONFIGFS_FS
+	help
+	  Select this configuration option to enable the Non-Transparent
+	  Bridge (NTB) driver for PCIe Endpoint. NTB driver implements NTB
+	  between PCI Root Port and PCIe Endpoint.
+
+	  If in doubt, say "N" to disable Endpoint NTB driver.
+
+config PCI_EPF_MHI
+	tristate "PCI Endpoint driver for MHI bus"
+	depends on PCI_ENDPOINT && MHI_BUS_EP
+	help
+	   Enable this configuration option to enable the PCI Endpoint
+	   driver for Modem Host Interface (MHI) bus in Qualcomm Endpoint
+	   devices such as SDX55.
+
+	   If in doubt, say "N" to disable Endpoint driver for MHI bus.
diff --git a/drivers/pci/endpoint/functions/Makefile b/drivers/pci/endpoint/functions/Makefile
new file mode 100644
index 0000000000..696473fce5
--- /dev/null
+++ b/drivers/pci/endpoint/functions/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for PCI Endpoint Functions
+#
+
+obj-$(CONFIG_PCI_EPF_TEST)		+= pci-epf-test.o
+obj-$(CONFIG_PCI_EPF_NTB)		+= pci-epf-ntb.o
+obj-$(CONFIG_PCI_EPF_VNTB) 		+= pci-epf-vntb.o
+obj-$(CONFIG_PCI_EPF_MHI)		+= pci-epf-mhi.o
diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
new file mode 100644
index 0000000000..6dc918a8a0
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -0,0 +1,716 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI EPF driver for MHI Endpoint devices
+ *
+ * Copyright (C) 2023 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/mhi_ep.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pci-epc.h>
+#include <linux/pci-epf.h>
+
+#define MHI_VERSION_1_0 0x01000000
+
+#define to_epf_mhi(cntrl) container_of(cntrl, struct pci_epf_mhi, cntrl)
+
+/* Platform specific flags */
+#define MHI_EPF_USE_DMA BIT(0)
+
+struct pci_epf_mhi_ep_info {
+	const struct mhi_ep_cntrl_config *config;
+	struct pci_epf_header *epf_header;
+	enum pci_barno bar_num;
+	u32 epf_flags;
+	u32 msi_count;
+	u32 mru;
+	u32 flags;
+};
+
+#define MHI_EP_CHANNEL_CONFIG(ch_num, ch_name, direction)	\
+	{							\
+		.num = ch_num,					\
+		.name = ch_name,				\
+		.dir = direction,				\
+	}
+
+#define MHI_EP_CHANNEL_CONFIG_UL(ch_num, ch_name)		\
+	MHI_EP_CHANNEL_CONFIG(ch_num, ch_name, DMA_TO_DEVICE)
+
+#define MHI_EP_CHANNEL_CONFIG_DL(ch_num, ch_name)		\
+	MHI_EP_CHANNEL_CONFIG(ch_num, ch_name, DMA_FROM_DEVICE)
+
+static const struct mhi_ep_channel_config mhi_v1_channels[] = {
+	MHI_EP_CHANNEL_CONFIG_UL(0, "LOOPBACK"),
+	MHI_EP_CHANNEL_CONFIG_DL(1, "LOOPBACK"),
+	MHI_EP_CHANNEL_CONFIG_UL(2, "SAHARA"),
+	MHI_EP_CHANNEL_CONFIG_DL(3, "SAHARA"),
+	MHI_EP_CHANNEL_CONFIG_UL(4, "DIAG"),
+	MHI_EP_CHANNEL_CONFIG_DL(5, "DIAG"),
+	MHI_EP_CHANNEL_CONFIG_UL(6, "SSR"),
+	MHI_EP_CHANNEL_CONFIG_DL(7, "SSR"),
+	MHI_EP_CHANNEL_CONFIG_UL(8, "QDSS"),
+	MHI_EP_CHANNEL_CONFIG_DL(9, "QDSS"),
+	MHI_EP_CHANNEL_CONFIG_UL(10, "EFS"),
+	MHI_EP_CHANNEL_CONFIG_DL(11, "EFS"),
+	MHI_EP_CHANNEL_CONFIG_UL(12, "MBIM"),
+	MHI_EP_CHANNEL_CONFIG_DL(13, "MBIM"),
+	MHI_EP_CHANNEL_CONFIG_UL(14, "QMI"),
+	MHI_EP_CHANNEL_CONFIG_DL(15, "QMI"),
+	MHI_EP_CHANNEL_CONFIG_UL(16, "QMI"),
+	MHI_EP_CHANNEL_CONFIG_DL(17, "QMI"),
+	MHI_EP_CHANNEL_CONFIG_UL(18, "IP-CTRL-1"),
+	MHI_EP_CHANNEL_CONFIG_DL(19, "IP-CTRL-1"),
+	MHI_EP_CHANNEL_CONFIG_UL(20, "IPCR"),
+	MHI_EP_CHANNEL_CONFIG_DL(21, "IPCR"),
+	MHI_EP_CHANNEL_CONFIG_UL(32, "DUN"),
+	MHI_EP_CHANNEL_CONFIG_DL(33, "DUN"),
+	MHI_EP_CHANNEL_CONFIG_UL(46, "IP_SW0"),
+	MHI_EP_CHANNEL_CONFIG_DL(47, "IP_SW0"),
+};
+
+static const struct mhi_ep_cntrl_config mhi_v1_config = {
+	.max_channels = 128,
+	.num_channels = ARRAY_SIZE(mhi_v1_channels),
+	.ch_cfg = mhi_v1_channels,
+	.mhi_version = MHI_VERSION_1_0,
+};
+
+static struct pci_epf_header sdx55_header = {
+	.vendorid = PCI_VENDOR_ID_QCOM,
+	.deviceid = 0x0306,
+	.baseclass_code = PCI_BASE_CLASS_COMMUNICATION,
+	.subclass_code = PCI_CLASS_COMMUNICATION_MODEM & 0xff,
+	.interrupt_pin	= PCI_INTERRUPT_INTA,
+};
+
+static const struct pci_epf_mhi_ep_info sdx55_info = {
+	.config = &mhi_v1_config,
+	.epf_header = &sdx55_header,
+	.bar_num = BAR_0,
+	.epf_flags = PCI_BASE_ADDRESS_MEM_TYPE_32,
+	.msi_count = 32,
+	.mru = 0x8000,
+};
+
+static struct pci_epf_header sm8450_header = {
+	.vendorid = PCI_VENDOR_ID_QCOM,
+	.deviceid = 0x0306,
+	.baseclass_code = PCI_CLASS_OTHERS,
+	.interrupt_pin = PCI_INTERRUPT_INTA,
+};
+
+static const struct pci_epf_mhi_ep_info sm8450_info = {
+	.config = &mhi_v1_config,
+	.epf_header = &sm8450_header,
+	.bar_num = BAR_0,
+	.epf_flags = PCI_BASE_ADDRESS_MEM_TYPE_32,
+	.msi_count = 32,
+	.mru = 0x8000,
+	.flags = MHI_EPF_USE_DMA,
+};
+
+struct pci_epf_mhi {
+	const struct pci_epc_features *epc_features;
+	const struct pci_epf_mhi_ep_info *info;
+	struct mhi_ep_cntrl mhi_cntrl;
+	struct pci_epf *epf;
+	struct mutex lock;
+	void __iomem *mmio;
+	resource_size_t mmio_phys;
+	struct dma_chan *dma_chan_tx;
+	struct dma_chan *dma_chan_rx;
+	u32 mmio_size;
+	int irq;
+};
+
+static size_t get_align_offset(struct pci_epf_mhi *epf_mhi, u64 addr)
+{
+	return addr & (epf_mhi->epc_features->align -1);
+}
+
+static int __pci_epf_mhi_alloc_map(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr,
+				 phys_addr_t *paddr, void __iomem **vaddr,
+				 size_t offset, size_t size)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct pci_epf *epf = epf_mhi->epf;
+	struct pci_epc *epc = epf->epc;
+	int ret;
+
+	*vaddr = pci_epc_mem_alloc_addr(epc, paddr, size + offset);
+	if (!*vaddr)
+		return -ENOMEM;
+
+	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, *paddr,
+			       pci_addr - offset, size + offset);
+	if (ret) {
+		pci_epc_mem_free_addr(epc, *paddr, *vaddr, size + offset);
+		return ret;
+	}
+
+	*paddr = *paddr + offset;
+	*vaddr = *vaddr + offset;
+
+	return 0;
+}
+
+static int pci_epf_mhi_alloc_map(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr,
+				 phys_addr_t *paddr, void __iomem **vaddr,
+				 size_t size)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	size_t offset = get_align_offset(epf_mhi, pci_addr);
+
+	return __pci_epf_mhi_alloc_map(mhi_cntrl, pci_addr, paddr, vaddr,
+				      offset, size);
+}
+
+static void __pci_epf_mhi_unmap_free(struct mhi_ep_cntrl *mhi_cntrl,
+				     u64 pci_addr, phys_addr_t paddr,
+				     void __iomem *vaddr, size_t offset,
+				     size_t size)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct pci_epf *epf = epf_mhi->epf;
+	struct pci_epc *epc = epf->epc;
+
+	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, paddr - offset);
+	pci_epc_mem_free_addr(epc, paddr - offset, vaddr - offset,
+			      size + offset);
+}
+
+static void pci_epf_mhi_unmap_free(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr,
+				   phys_addr_t paddr, void __iomem *vaddr,
+				   size_t size)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	size_t offset = get_align_offset(epf_mhi, pci_addr);
+
+	__pci_epf_mhi_unmap_free(mhi_cntrl, pci_addr, paddr, vaddr, offset,
+				 size);
+}
+
+static void pci_epf_mhi_raise_irq(struct mhi_ep_cntrl *mhi_cntrl, u32 vector)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct pci_epf *epf = epf_mhi->epf;
+	struct pci_epc *epc = epf->epc;
+
+	/*
+	 * MHI supplies 0 based MSI vectors but the API expects the vector
+	 * number to start from 1, so we need to increment the vector by 1.
+	 */
+	pci_epc_raise_irq(epc, epf->func_no, epf->vfunc_no, PCI_EPC_IRQ_MSI,
+			  vector + 1);
+}
+
+static int pci_epf_mhi_iatu_read(struct mhi_ep_cntrl *mhi_cntrl,
+				 struct mhi_ep_buf_info *buf_info)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	size_t offset = get_align_offset(epf_mhi, buf_info->host_addr);
+	void __iomem *tre_buf;
+	phys_addr_t tre_phys;
+	int ret;
+
+	mutex_lock(&epf_mhi->lock);
+
+	ret = __pci_epf_mhi_alloc_map(mhi_cntrl, buf_info->host_addr, &tre_phys,
+				      &tre_buf, offset, buf_info->size);
+	if (ret) {
+		mutex_unlock(&epf_mhi->lock);
+		return ret;
+	}
+
+	memcpy_fromio(buf_info->dev_addr, tre_buf, buf_info->size);
+
+	__pci_epf_mhi_unmap_free(mhi_cntrl, buf_info->host_addr, tre_phys,
+				 tre_buf, offset, buf_info->size);
+
+	mutex_unlock(&epf_mhi->lock);
+
+	return 0;
+}
+
+static int pci_epf_mhi_iatu_write(struct mhi_ep_cntrl *mhi_cntrl,
+				  struct mhi_ep_buf_info *buf_info)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	size_t offset = get_align_offset(epf_mhi, buf_info->host_addr);
+	void __iomem *tre_buf;
+	phys_addr_t tre_phys;
+	int ret;
+
+	mutex_lock(&epf_mhi->lock);
+
+	ret = __pci_epf_mhi_alloc_map(mhi_cntrl, buf_info->host_addr, &tre_phys,
+				      &tre_buf, offset, buf_info->size);
+	if (ret) {
+		mutex_unlock(&epf_mhi->lock);
+		return ret;
+	}
+
+	memcpy_toio(tre_buf, buf_info->dev_addr, buf_info->size);
+
+	__pci_epf_mhi_unmap_free(mhi_cntrl, buf_info->host_addr, tre_phys,
+				 tre_buf, offset, buf_info->size);
+
+	mutex_unlock(&epf_mhi->lock);
+
+	return 0;
+}
+
+static void pci_epf_mhi_dma_callback(void *param)
+{
+	complete(param);
+}
+
+static int pci_epf_mhi_edma_read(struct mhi_ep_cntrl *mhi_cntrl,
+				 struct mhi_ep_buf_info *buf_info)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct device *dma_dev = epf_mhi->epf->epc->dev.parent;
+	struct dma_chan *chan = epf_mhi->dma_chan_rx;
+	struct device *dev = &epf_mhi->epf->dev;
+	DECLARE_COMPLETION_ONSTACK(complete);
+	struct dma_async_tx_descriptor *desc;
+	struct dma_slave_config config = {};
+	dma_cookie_t cookie;
+	dma_addr_t dst_addr;
+	int ret;
+
+	if (buf_info->size < SZ_4K)
+		return pci_epf_mhi_iatu_read(mhi_cntrl, buf_info);
+
+	mutex_lock(&epf_mhi->lock);
+
+	config.direction = DMA_DEV_TO_MEM;
+	config.src_addr = buf_info->host_addr;
+
+	ret = dmaengine_slave_config(chan, &config);
+	if (ret) {
+		dev_err(dev, "Failed to configure DMA channel\n");
+		goto err_unlock;
+	}
+
+	dst_addr = dma_map_single(dma_dev, buf_info->dev_addr, buf_info->size,
+				  DMA_FROM_DEVICE);
+	ret = dma_mapping_error(dma_dev, dst_addr);
+	if (ret) {
+		dev_err(dev, "Failed to map remote memory\n");
+		goto err_unlock;
+	}
+
+	desc = dmaengine_prep_slave_single(chan, dst_addr, buf_info->size,
+					   DMA_DEV_TO_MEM,
+					   DMA_CTRL_ACK | DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(dev, "Failed to prepare DMA\n");
+		ret = -EIO;
+		goto err_unmap;
+	}
+
+	desc->callback = pci_epf_mhi_dma_callback;
+	desc->callback_param = &complete;
+
+	cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dev_err(dev, "Failed to do DMA submit\n");
+		goto err_unmap;
+	}
+
+	dma_async_issue_pending(chan);
+	ret = wait_for_completion_timeout(&complete, msecs_to_jiffies(1000));
+	if (!ret) {
+		dev_err(dev, "DMA transfer timeout\n");
+		dmaengine_terminate_sync(chan);
+		ret = -ETIMEDOUT;
+	}
+
+err_unmap:
+	dma_unmap_single(dma_dev, dst_addr, buf_info->size, DMA_FROM_DEVICE);
+err_unlock:
+	mutex_unlock(&epf_mhi->lock);
+
+	return ret;
+}
+
+static int pci_epf_mhi_edma_write(struct mhi_ep_cntrl *mhi_cntrl,
+				  struct mhi_ep_buf_info *buf_info)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct device *dma_dev = epf_mhi->epf->epc->dev.parent;
+	struct dma_chan *chan = epf_mhi->dma_chan_tx;
+	struct device *dev = &epf_mhi->epf->dev;
+	DECLARE_COMPLETION_ONSTACK(complete);
+	struct dma_async_tx_descriptor *desc;
+	struct dma_slave_config config = {};
+	dma_cookie_t cookie;
+	dma_addr_t src_addr;
+	int ret;
+
+	if (buf_info->size < SZ_4K)
+		return pci_epf_mhi_iatu_write(mhi_cntrl, buf_info);
+
+	mutex_lock(&epf_mhi->lock);
+
+	config.direction = DMA_MEM_TO_DEV;
+	config.dst_addr = buf_info->host_addr;
+
+	ret = dmaengine_slave_config(chan, &config);
+	if (ret) {
+		dev_err(dev, "Failed to configure DMA channel\n");
+		goto err_unlock;
+	}
+
+	src_addr = dma_map_single(dma_dev, buf_info->dev_addr, buf_info->size,
+				  DMA_TO_DEVICE);
+	ret = dma_mapping_error(dma_dev, src_addr);
+	if (ret) {
+		dev_err(dev, "Failed to map remote memory\n");
+		goto err_unlock;
+	}
+
+	desc = dmaengine_prep_slave_single(chan, src_addr, buf_info->size,
+					   DMA_MEM_TO_DEV,
+					   DMA_CTRL_ACK | DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(dev, "Failed to prepare DMA\n");
+		ret = -EIO;
+		goto err_unmap;
+	}
+
+	desc->callback = pci_epf_mhi_dma_callback;
+	desc->callback_param = &complete;
+
+	cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dev_err(dev, "Failed to do DMA submit\n");
+		goto err_unmap;
+	}
+
+	dma_async_issue_pending(chan);
+	ret = wait_for_completion_timeout(&complete, msecs_to_jiffies(1000));
+	if (!ret) {
+		dev_err(dev, "DMA transfer timeout\n");
+		dmaengine_terminate_sync(chan);
+		ret = -ETIMEDOUT;
+	}
+
+err_unmap:
+	dma_unmap_single(dma_dev, src_addr, buf_info->size, DMA_TO_DEVICE);
+err_unlock:
+	mutex_unlock(&epf_mhi->lock);
+
+	return ret;
+}
+
+struct epf_dma_filter {
+	struct device *dev;
+	u32 dma_mask;
+};
+
+static bool pci_epf_mhi_filter(struct dma_chan *chan, void *node)
+{
+	struct epf_dma_filter *filter = node;
+	struct dma_slave_caps caps;
+
+	memset(&caps, 0, sizeof(caps));
+	dma_get_slave_caps(chan, &caps);
+
+	return chan->device->dev == filter->dev && filter->dma_mask &
+					caps.directions;
+}
+
+static int pci_epf_mhi_dma_init(struct pci_epf_mhi *epf_mhi)
+{
+	struct device *dma_dev = epf_mhi->epf->epc->dev.parent;
+	struct device *dev = &epf_mhi->epf->dev;
+	struct epf_dma_filter filter;
+	dma_cap_mask_t mask;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	filter.dev = dma_dev;
+	filter.dma_mask = BIT(DMA_MEM_TO_DEV);
+	epf_mhi->dma_chan_tx = dma_request_channel(mask, pci_epf_mhi_filter,
+						   &filter);
+	if (IS_ERR_OR_NULL(epf_mhi->dma_chan_tx)) {
+		dev_err(dev, "Failed to request tx channel\n");
+		return -ENODEV;
+	}
+
+	filter.dma_mask = BIT(DMA_DEV_TO_MEM);
+	epf_mhi->dma_chan_rx = dma_request_channel(mask, pci_epf_mhi_filter,
+						   &filter);
+	if (IS_ERR_OR_NULL(epf_mhi->dma_chan_rx)) {
+		dev_err(dev, "Failed to request rx channel\n");
+		dma_release_channel(epf_mhi->dma_chan_tx);
+		epf_mhi->dma_chan_tx = NULL;
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void pci_epf_mhi_dma_deinit(struct pci_epf_mhi *epf_mhi)
+{
+	dma_release_channel(epf_mhi->dma_chan_tx);
+	dma_release_channel(epf_mhi->dma_chan_rx);
+	epf_mhi->dma_chan_tx = NULL;
+	epf_mhi->dma_chan_rx = NULL;
+}
+
+static int pci_epf_mhi_core_init(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+	struct pci_epf_bar *epf_bar = &epf->bar[info->bar_num];
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	int ret;
+
+	epf_bar->phys_addr = epf_mhi->mmio_phys;
+	epf_bar->size = epf_mhi->mmio_size;
+	epf_bar->barno = info->bar_num;
+	epf_bar->flags = info->epf_flags;
+	ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, epf_bar);
+	if (ret) {
+		dev_err(dev, "Failed to set BAR: %d\n", ret);
+		return ret;
+	}
+
+	ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
+			      order_base_2(info->msi_count));
+	if (ret) {
+		dev_err(dev, "Failed to set MSI configuration: %d\n", ret);
+		return ret;
+	}
+
+	ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no,
+				   epf->header);
+	if (ret) {
+		dev_err(dev, "Failed to set Configuration header: %d\n", ret);
+		return ret;
+	}
+
+	epf_mhi->epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
+	if (!epf_mhi->epc_features)
+		return -ENODATA;
+
+	return 0;
+}
+
+static int pci_epf_mhi_link_up(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	int ret;
+
+	if (info->flags & MHI_EPF_USE_DMA) {
+		ret = pci_epf_mhi_dma_init(epf_mhi);
+		if (ret) {
+			dev_err(dev, "Failed to initialize DMA: %d\n", ret);
+			return ret;
+		}
+	}
+
+	mhi_cntrl->mmio = epf_mhi->mmio;
+	mhi_cntrl->irq = epf_mhi->irq;
+	mhi_cntrl->mru = info->mru;
+
+	/* Assign the struct dev of PCI EP as MHI controller device */
+	mhi_cntrl->cntrl_dev = epc->dev.parent;
+	mhi_cntrl->raise_irq = pci_epf_mhi_raise_irq;
+	mhi_cntrl->alloc_map = pci_epf_mhi_alloc_map;
+	mhi_cntrl->unmap_free = pci_epf_mhi_unmap_free;
+	if (info->flags & MHI_EPF_USE_DMA) {
+		mhi_cntrl->read_from_host = pci_epf_mhi_edma_read;
+		mhi_cntrl->write_to_host = pci_epf_mhi_edma_write;
+	} else {
+		mhi_cntrl->read_from_host = pci_epf_mhi_iatu_read;
+		mhi_cntrl->write_to_host = pci_epf_mhi_iatu_write;
+	}
+
+	/* Register the MHI EP controller */
+	ret = mhi_ep_register_controller(mhi_cntrl, info->config);
+	if (ret) {
+		dev_err(dev, "Failed to register MHI EP controller: %d\n", ret);
+		if (info->flags & MHI_EPF_USE_DMA)
+			pci_epf_mhi_dma_deinit(epf_mhi);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int pci_epf_mhi_link_down(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+
+	if (mhi_cntrl->mhi_dev) {
+		mhi_ep_power_down(mhi_cntrl);
+		if (info->flags & MHI_EPF_USE_DMA)
+			pci_epf_mhi_dma_deinit(epf_mhi);
+		mhi_ep_unregister_controller(mhi_cntrl);
+	}
+
+	return 0;
+}
+
+static int pci_epf_mhi_bme(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+	struct device *dev = &epf->dev;
+	int ret;
+
+	/*
+	 * Power up the MHI EP stack if link is up and stack is in power down
+	 * state.
+	 */
+	if (!mhi_cntrl->enabled && mhi_cntrl->mhi_dev) {
+		ret = mhi_ep_power_up(mhi_cntrl);
+		if (ret) {
+			dev_err(dev, "Failed to power up MHI EP: %d\n", ret);
+			if (info->flags & MHI_EPF_USE_DMA)
+				pci_epf_mhi_dma_deinit(epf_mhi);
+			mhi_ep_unregister_controller(mhi_cntrl);
+		}
+	}
+
+	return 0;
+}
+
+static int pci_epf_mhi_bind(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	struct pci_epc *epc = epf->epc;
+	struct platform_device *pdev = to_platform_device(epc->dev.parent);
+	struct resource *res;
+	int ret;
+
+	/* Get MMIO base address from Endpoint controller */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mmio");
+	epf_mhi->mmio_phys = res->start;
+	epf_mhi->mmio_size = resource_size(res);
+
+	epf_mhi->mmio = ioremap(epf_mhi->mmio_phys, epf_mhi->mmio_size);
+	if (!epf_mhi->mmio)
+		return -ENOMEM;
+
+	ret = platform_get_irq_byname(pdev, "doorbell");
+	if (ret < 0) {
+		iounmap(epf_mhi->mmio);
+		return ret;
+	}
+
+	epf_mhi->irq = ret;
+
+	return 0;
+}
+
+static void pci_epf_mhi_unbind(struct pci_epf *epf)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
+	struct pci_epf_bar *epf_bar = &epf->bar[info->bar_num];
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+	struct pci_epc *epc = epf->epc;
+
+	/*
+	 * Forcefully power down the MHI EP stack. Only way to bring the MHI EP
+	 * stack back to working state after successive bind is by getting BME
+	 * from host.
+	 */
+	if (mhi_cntrl->mhi_dev) {
+		mhi_ep_power_down(mhi_cntrl);
+		if (info->flags & MHI_EPF_USE_DMA)
+			pci_epf_mhi_dma_deinit(epf_mhi);
+		mhi_ep_unregister_controller(mhi_cntrl);
+	}
+
+	iounmap(epf_mhi->mmio);
+	pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no, epf_bar);
+}
+
+static struct pci_epc_event_ops pci_epf_mhi_event_ops = {
+	.core_init = pci_epf_mhi_core_init,
+	.link_up = pci_epf_mhi_link_up,
+	.link_down = pci_epf_mhi_link_down,
+	.bme = pci_epf_mhi_bme,
+};
+
+static int pci_epf_mhi_probe(struct pci_epf *epf,
+			     const struct pci_epf_device_id *id)
+{
+	struct pci_epf_mhi_ep_info *info =
+			(struct pci_epf_mhi_ep_info *)id->driver_data;
+	struct pci_epf_mhi *epf_mhi;
+	struct device *dev = &epf->dev;
+
+	epf_mhi = devm_kzalloc(dev, sizeof(*epf_mhi), GFP_KERNEL);
+	if (!epf_mhi)
+		return -ENOMEM;
+
+	epf->header = info->epf_header;
+	epf_mhi->info = info;
+	epf_mhi->epf = epf;
+
+	epf->event_ops = &pci_epf_mhi_event_ops;
+
+	mutex_init(&epf_mhi->lock);
+
+	epf_set_drvdata(epf, epf_mhi);
+
+	return 0;
+}
+
+static const struct pci_epf_device_id pci_epf_mhi_ids[] = {
+	{ .name = "sdx55", .driver_data = (kernel_ulong_t)&sdx55_info },
+	{ .name = "sm8450", .driver_data = (kernel_ulong_t)&sm8450_info },
+	{},
+};
+
+static struct pci_epf_ops pci_epf_mhi_ops = {
+	.unbind	= pci_epf_mhi_unbind,
+	.bind	= pci_epf_mhi_bind,
+};
+
+static struct pci_epf_driver pci_epf_mhi_driver = {
+	.driver.name	= "pci_epf_mhi",
+	.probe		= pci_epf_mhi_probe,
+	.id_table	= pci_epf_mhi_ids,
+	.ops		= &pci_epf_mhi_ops,
+	.owner		= THIS_MODULE,
+};
+
+static int __init pci_epf_mhi_init(void)
+{
+	return pci_epf_register_driver(&pci_epf_mhi_driver);
+}
+module_init(pci_epf_mhi_init);
+
+static void __exit pci_epf_mhi_exit(void)
+{
+	pci_epf_unregister_driver(&pci_epf_mhi_driver);
+}
+module_exit(pci_epf_mhi_exit);
+
+MODULE_DESCRIPTION("PCI EPF driver for MHI Endpoint devices");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_LICENSE("GPL");
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 0000000000..9aac2c6f3b
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-ntb.c
@@ -0,0 +1,2149 @@
+// 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;
+	u8 vfunc_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;
+	u8 func_no, vfunc_no;
+	bool is_msix;
+	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;
+		vfunc_no = ntb_epc->vfunc_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, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	u64 addr, size;
+	int ret = 0;
+
+	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;
+	vfunc_no = ntb_epc->vfunc_no;
+
+	ret = pci_epc_map_addr(epc, func_no, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+
+	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;
+	vfunc_no = ntb_epc->vfunc_no;
+
+	pci_epc_unmap_addr(epc, func_no, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	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;
+	vfunc_no = ntb_epc->vfunc_no;
+
+	ret = pci_epc_map_msi_irq(epc, func_no, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	size_t align;
+	u64 msg_addr;
+	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;
+	vfunc_no = ntb_epc->vfunc_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, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+
+	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;
+	vfunc_no = ntb_epc->vfunc_no;
+
+	pci_epc_unmap_addr(epc, func_no, vfunc_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_epc: EPC associated with one of the HOST which holds peer's outbound
+ *	     address.
+ *
+ *+-----------------+------->+------------------+        +-----------------+
+ *|       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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	vfunc_no = ntb_epc->vfunc_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_PEER_SPAD];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	pci_epc_clear_bar(epc, func_no, vfunc_no, epf_bar);
+}
+
+/**
+ * epf_ntb_peer_spad_bar_set() - Set peer scratchpad BAR
+ * @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
+ *
+ * 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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	struct device *dev;
+	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;
+	vfunc_no = ntb_epc->vfunc_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, vfunc_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_epc: EPC associated with one of the HOST which holds peer's outbound
+ *	     address.
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	vfunc_no = ntb_epc->vfunc_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb_epc->epf_bar[barno];
+	pci_epc_clear_bar(epc, func_no, vfunc_no, epf_bar);
+}
+
+/**
+ * epf_ntb_config_sspad_bar_set() - Set Config + Self scratchpad BAR
+ * @ntb_epc: EPC associated with one of the HOST which holds peer's outbound
+ *	     address.
+ *
+ * +-----------------+------->+------------------+        +-----------------+
+ * |       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;
+	u8 func_no, vfunc_no;
+	struct epf_ntb *ntb;
+	struct pci_epc *epc;
+	struct device *dev;
+	int ret;
+
+	ntb = ntb_epc->epf_ntb;
+	dev = &ntb->epf->dev;
+
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	vfunc_no = ntb_epc->vfunc_no;
+	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb_epc->epf_bar[barno];
+
+	ret = pci_epc_set_bar(epc, func_no, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+
+	epc = ntb_epc->epc;
+
+	func_no = ntb_epc->func_no;
+	vfunc_no = ntb_epc->vfunc_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, vfunc_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 capability
+ * @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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	struct device *dev;
+	u32 db_count;
+	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;
+	vfunc_no = ntb_epc->vfunc_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, vfunc_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, vfunc_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
+ * @dev: The PCI device.
+ * @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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	struct device *dev;
+	size_t align;
+	int ret, i;
+	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;
+	vfunc_no = ntb_epc->vfunc_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, vfunc_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;
+	u8 func_no, vfunc_no;
+	struct pci_epf *epf;
+	struct device *dev;
+
+	dev = &ntb->epf->dev;
+
+	ntb_epc = devm_kzalloc(dev, sizeof(*ntb_epc), GFP_KERNEL);
+	if (!ntb_epc)
+		return -ENOMEM;
+
+	epf = ntb->epf;
+	vfunc_no = epf->vfunc_no;
+	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->vfunc_no = vfunc_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, vfunc_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
+ *
+ * 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;
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+	struct device *dev;
+	int ret;
+
+	ntb_epc = ntb->epc[type];
+	epf = ntb->epf;
+	dev = &epf->dev;
+	epc = ntb_epc->epc;
+	func_no = ntb_epc->func_no;
+	vfunc_no = ntb_epc->vfunc_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;
+	}
+
+	if (vfunc_no <= 1) {
+		ret = pci_epc_write_header(epc, func_no, vfunc_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 sysfs_emit(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;							\
+									\
+	if (kstrtou32(page, 0, &val) < 0)				\
+		return -EINVAL;						\
+									\
+	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 sysfs_emit(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;							\
+									\
+	if (kstrtou64(page, 0, &val) < 0)				\
+		return -EINVAL;						\
+									\
+	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;
+
+	if (kstrtou32(page, 0, &val) < 0)
+		return -EINVAL;
+
+	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
+ * @group: A pointer to the config_group structure referencing a group of
+ *	   config_items of a specific type that belong to a specific sub-system.
+ *
+ * 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
+ * @id: NTB endpoint function device ID
+ *
+ * Probe NTB function driver when endpoint function bus detects a NTB
+ * endpoint function.
+ */
+static int epf_ntb_probe(struct pci_epf *epf,
+			 const struct pci_epf_device_id *id)
+{
+	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
new file mode 100644
index 0000000000..1f0d2b8429
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -0,0 +1,1021 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test driver to test endpoint functionality
+ *
+ * Copyright (C) 2017 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ */
+
+#include <linux/crc32.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pci_ids.h>
+#include <linux/random.h>
+
+#include <linux/pci-epc.h>
+#include <linux/pci-epf.h>
+#include <linux/pci_regs.h>
+
+#define IRQ_TYPE_LEGACY			0
+#define IRQ_TYPE_MSI			1
+#define IRQ_TYPE_MSIX			2
+
+#define COMMAND_RAISE_LEGACY_IRQ	BIT(0)
+#define COMMAND_RAISE_MSI_IRQ		BIT(1)
+#define COMMAND_RAISE_MSIX_IRQ		BIT(2)
+#define COMMAND_READ			BIT(3)
+#define COMMAND_WRITE			BIT(4)
+#define COMMAND_COPY			BIT(5)
+
+#define STATUS_READ_SUCCESS		BIT(0)
+#define STATUS_READ_FAIL		BIT(1)
+#define STATUS_WRITE_SUCCESS		BIT(2)
+#define STATUS_WRITE_FAIL		BIT(3)
+#define STATUS_COPY_SUCCESS		BIT(4)
+#define STATUS_COPY_FAIL		BIT(5)
+#define STATUS_IRQ_RAISED		BIT(6)
+#define STATUS_SRC_ADDR_INVALID		BIT(7)
+#define STATUS_DST_ADDR_INVALID		BIT(8)
+
+#define FLAG_USE_DMA			BIT(0)
+
+#define TIMER_RESOLUTION		1
+
+static struct workqueue_struct *kpcitest_workqueue;
+
+struct pci_epf_test {
+	void			*reg[PCI_STD_NUM_BARS];
+	struct pci_epf		*epf;
+	enum pci_barno		test_reg_bar;
+	size_t			msix_table_offset;
+	struct delayed_work	cmd_handler;
+	struct dma_chan		*dma_chan_tx;
+	struct dma_chan		*dma_chan_rx;
+	struct dma_chan		*transfer_chan;
+	dma_cookie_t		transfer_cookie;
+	enum dma_status		transfer_status;
+	struct completion	transfer_complete;
+	bool			dma_supported;
+	bool			dma_private;
+	const struct pci_epc_features *epc_features;
+};
+
+struct pci_epf_test_reg {
+	u32	magic;
+	u32	command;
+	u32	status;
+	u64	src_addr;
+	u64	dst_addr;
+	u32	size;
+	u32	checksum;
+	u32	irq_type;
+	u32	irq_number;
+	u32	flags;
+} __packed;
+
+static struct pci_epf_header test_header = {
+	.vendorid	= PCI_ANY_ID,
+	.deviceid	= PCI_ANY_ID,
+	.baseclass_code = PCI_CLASS_OTHERS,
+	.interrupt_pin	= PCI_INTERRUPT_INTA,
+};
+
+static size_t bar_size[] = { 512, 512, 1024, 16384, 131072, 1048576 };
+
+static void pci_epf_test_dma_callback(void *param)
+{
+	struct pci_epf_test *epf_test = param;
+	struct dma_tx_state state;
+
+	epf_test->transfer_status =
+		dmaengine_tx_status(epf_test->transfer_chan,
+				    epf_test->transfer_cookie, &state);
+	if (epf_test->transfer_status == DMA_COMPLETE ||
+	    epf_test->transfer_status == DMA_ERROR)
+		complete(&epf_test->transfer_complete);
+}
+
+/**
+ * pci_epf_test_data_transfer() - Function that uses dmaengine API to transfer
+ *				  data between PCIe EP and remote PCIe RC
+ * @epf_test: the EPF test device that performs the data transfer operation
+ * @dma_dst: The destination address of the data transfer. It can be a physical
+ *	     address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
+ * @dma_src: The source address of the data transfer. It can be a physical
+ *	     address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
+ * @len: The size of the data transfer
+ * @dma_remote: remote RC physical address
+ * @dir: DMA transfer direction
+ *
+ * Function that uses dmaengine API to transfer data between PCIe EP and remote
+ * PCIe RC. The source and destination address can be a physical address given
+ * by pci_epc_mem_alloc_addr or the one obtained using DMA mapping APIs.
+ *
+ * The function returns '0' on success and negative value on failure.
+ */
+static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test,
+				      dma_addr_t dma_dst, dma_addr_t dma_src,
+				      size_t len, dma_addr_t dma_remote,
+				      enum dma_transfer_direction dir)
+{
+	struct dma_chan *chan = (dir == DMA_MEM_TO_DEV) ?
+				 epf_test->dma_chan_tx : epf_test->dma_chan_rx;
+	dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst;
+	enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
+	struct pci_epf *epf = epf_test->epf;
+	struct dma_async_tx_descriptor *tx;
+	struct dma_slave_config sconf = {};
+	struct device *dev = &epf->dev;
+	int ret;
+
+	if (IS_ERR_OR_NULL(chan)) {
+		dev_err(dev, "Invalid DMA memcpy channel\n");
+		return -EINVAL;
+	}
+
+	if (epf_test->dma_private) {
+		sconf.direction = dir;
+		if (dir == DMA_MEM_TO_DEV)
+			sconf.dst_addr = dma_remote;
+		else
+			sconf.src_addr = dma_remote;
+
+		if (dmaengine_slave_config(chan, &sconf)) {
+			dev_err(dev, "DMA slave config fail\n");
+			return -EIO;
+		}
+		tx = dmaengine_prep_slave_single(chan, dma_local, len, dir,
+						 flags);
+	} else {
+		tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len,
+					       flags);
+	}
+
+	if (!tx) {
+		dev_err(dev, "Failed to prepare DMA memcpy\n");
+		return -EIO;
+	}
+
+	reinit_completion(&epf_test->transfer_complete);
+	epf_test->transfer_chan = chan;
+	tx->callback = pci_epf_test_dma_callback;
+	tx->callback_param = epf_test;
+	epf_test->transfer_cookie = dmaengine_submit(tx);
+
+	ret = dma_submit_error(epf_test->transfer_cookie);
+	if (ret) {
+		dev_err(dev, "Failed to do DMA tx_submit %d\n", ret);
+		goto terminate;
+	}
+
+	dma_async_issue_pending(chan);
+	ret = wait_for_completion_interruptible(&epf_test->transfer_complete);
+	if (ret < 0) {
+		dev_err(dev, "DMA wait_for_completion interrupted\n");
+		goto terminate;
+	}
+
+	if (epf_test->transfer_status == DMA_ERROR) {
+		dev_err(dev, "DMA transfer failed\n");
+		ret = -EIO;
+	}
+
+terminate:
+	dmaengine_terminate_sync(chan);
+
+	return ret;
+}
+
+struct epf_dma_filter {
+	struct device *dev;
+	u32 dma_mask;
+};
+
+static bool epf_dma_filter_fn(struct dma_chan *chan, void *node)
+{
+	struct epf_dma_filter *filter = node;
+	struct dma_slave_caps caps;
+
+	memset(&caps, 0, sizeof(caps));
+	dma_get_slave_caps(chan, &caps);
+
+	return chan->device->dev == filter->dev
+		&& (filter->dma_mask & caps.directions);
+}
+
+/**
+ * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel
+ * @epf_test: the EPF test device that performs data transfer operation
+ *
+ * Function to initialize EPF test DMA channel.
+ */
+static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test)
+{
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct epf_dma_filter filter;
+	struct dma_chan *dma_chan;
+	dma_cap_mask_t mask;
+	int ret;
+
+	filter.dev = epf->epc->dev.parent;
+	filter.dma_mask = BIT(DMA_DEV_TO_MEM);
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter);
+	if (!dma_chan) {
+		dev_info(dev, "Failed to get private DMA rx channel. Falling back to generic one\n");
+		goto fail_back_tx;
+	}
+
+	epf_test->dma_chan_rx = dma_chan;
+
+	filter.dma_mask = BIT(DMA_MEM_TO_DEV);
+	dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter);
+
+	if (!dma_chan) {
+		dev_info(dev, "Failed to get private DMA tx channel. Falling back to generic one\n");
+		goto fail_back_rx;
+	}
+
+	epf_test->dma_chan_tx = dma_chan;
+	epf_test->dma_private = true;
+
+	init_completion(&epf_test->transfer_complete);
+
+	return 0;
+
+fail_back_rx:
+	dma_release_channel(epf_test->dma_chan_rx);
+	epf_test->dma_chan_tx = NULL;
+
+fail_back_tx:
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_MEMCPY, mask);
+
+	dma_chan = dma_request_chan_by_mask(&mask);
+	if (IS_ERR(dma_chan)) {
+		ret = PTR_ERR(dma_chan);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get DMA channel\n");
+		return ret;
+	}
+	init_completion(&epf_test->transfer_complete);
+
+	epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan;
+
+	return 0;
+}
+
+/**
+ * pci_epf_test_clean_dma_chan() - Function to cleanup EPF test DMA channel
+ * @epf_test: the EPF test device that performs data transfer operation
+ *
+ * Helper to cleanup EPF test DMA channel.
+ */
+static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test)
+{
+	if (!epf_test->dma_supported)
+		return;
+
+	dma_release_channel(epf_test->dma_chan_tx);
+	if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) {
+		epf_test->dma_chan_tx = NULL;
+		epf_test->dma_chan_rx = NULL;
+		return;
+	}
+
+	dma_release_channel(epf_test->dma_chan_rx);
+	epf_test->dma_chan_rx = NULL;
+
+	return;
+}
+
+static void pci_epf_test_print_rate(struct pci_epf_test *epf_test,
+				    const char *op, u64 size,
+				    struct timespec64 *start,
+				    struct timespec64 *end, bool dma)
+{
+	struct timespec64 ts = timespec64_sub(*end, *start);
+	u64 rate = 0, ns;
+
+	/* calculate the rate */
+	ns = timespec64_to_ns(&ts);
+	if (ns)
+		rate = div64_u64(size * NSEC_PER_SEC, ns * 1000);
+
+	dev_info(&epf_test->epf->dev,
+		 "%s => Size: %llu B, DMA: %s, Time: %llu.%09u s, Rate: %llu KB/s\n",
+		 op, size, dma ? "YES" : "NO",
+		 (u64)ts.tv_sec, (u32)ts.tv_nsec, rate);
+}
+
+static void pci_epf_test_copy(struct pci_epf_test *epf_test,
+			      struct pci_epf_test_reg *reg)
+{
+	int ret;
+	void __iomem *src_addr;
+	void __iomem *dst_addr;
+	phys_addr_t src_phys_addr;
+	phys_addr_t dst_phys_addr;
+	struct timespec64 start, end;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+
+	src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
+	if (!src_addr) {
+		dev_err(dev, "Failed to allocate source address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, src_phys_addr,
+			       reg->src_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "Failed to map source address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		goto err_src_addr;
+	}
+
+	dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
+	if (!dst_addr) {
+		dev_err(dev, "Failed to allocate destination address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err_src_map_addr;
+	}
+
+	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr,
+			       reg->dst_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "Failed to map destination address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		goto err_dst_addr;
+	}
+
+	ktime_get_ts64(&start);
+	if (reg->flags & FLAG_USE_DMA) {
+		if (epf_test->dma_private) {
+			dev_err(dev, "Cannot transfer data using DMA\n");
+			ret = -EINVAL;
+			goto err_map_addr;
+		}
+
+		ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
+						 src_phys_addr, reg->size, 0,
+						 DMA_MEM_TO_MEM);
+		if (ret)
+			dev_err(dev, "Data transfer failed\n");
+	} else {
+		void *buf;
+
+		buf = kzalloc(reg->size, GFP_KERNEL);
+		if (!buf) {
+			ret = -ENOMEM;
+			goto err_map_addr;
+		}
+
+		memcpy_fromio(buf, src_addr, reg->size);
+		memcpy_toio(dst_addr, buf, reg->size);
+		kfree(buf);
+	}
+	ktime_get_ts64(&end);
+	pci_epf_test_print_rate(epf_test, "COPY", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
+
+err_map_addr:
+	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, dst_phys_addr);
+
+err_dst_addr:
+	pci_epc_mem_free_addr(epc, dst_phys_addr, dst_addr, reg->size);
+
+err_src_map_addr:
+	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, src_phys_addr);
+
+err_src_addr:
+	pci_epc_mem_free_addr(epc, src_phys_addr, src_addr, reg->size);
+
+err:
+	if (!ret)
+		reg->status |= STATUS_COPY_SUCCESS;
+	else
+		reg->status |= STATUS_COPY_FAIL;
+}
+
+static void pci_epf_test_read(struct pci_epf_test *epf_test,
+			      struct pci_epf_test_reg *reg)
+{
+	int ret;
+	void __iomem *src_addr;
+	void *buf;
+	u32 crc32;
+	phys_addr_t phys_addr;
+	phys_addr_t dst_phys_addr;
+	struct timespec64 start, end;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	struct device *dma_dev = epf->epc->dev.parent;
+
+	src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+	if (!src_addr) {
+		dev_err(dev, "Failed to allocate address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
+			       reg->src_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "Failed to map address\n");
+		reg->status = STATUS_SRC_ADDR_INVALID;
+		goto err_addr;
+	}
+
+	buf = kzalloc(reg->size, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto err_map_addr;
+	}
+
+	if (reg->flags & FLAG_USE_DMA) {
+		dst_phys_addr = dma_map_single(dma_dev, buf, reg->size,
+					       DMA_FROM_DEVICE);
+		if (dma_mapping_error(dma_dev, dst_phys_addr)) {
+			dev_err(dev, "Failed to map destination buffer addr\n");
+			ret = -ENOMEM;
+			goto err_dma_map;
+		}
+
+		ktime_get_ts64(&start);
+		ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
+						 phys_addr, reg->size,
+						 reg->src_addr, DMA_DEV_TO_MEM);
+		if (ret)
+			dev_err(dev, "Data transfer failed\n");
+		ktime_get_ts64(&end);
+
+		dma_unmap_single(dma_dev, dst_phys_addr, reg->size,
+				 DMA_FROM_DEVICE);
+	} else {
+		ktime_get_ts64(&start);
+		memcpy_fromio(buf, src_addr, reg->size);
+		ktime_get_ts64(&end);
+	}
+
+	pci_epf_test_print_rate(epf_test, "READ", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
+
+	crc32 = crc32_le(~0, buf, reg->size);
+	if (crc32 != reg->checksum)
+		ret = -EIO;
+
+err_dma_map:
+	kfree(buf);
+
+err_map_addr:
+	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+
+err_addr:
+	pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);
+
+err:
+	if (!ret)
+		reg->status |= STATUS_READ_SUCCESS;
+	else
+		reg->status |= STATUS_READ_FAIL;
+}
+
+static void pci_epf_test_write(struct pci_epf_test *epf_test,
+			       struct pci_epf_test_reg *reg)
+{
+	int ret;
+	void __iomem *dst_addr;
+	void *buf;
+	phys_addr_t phys_addr;
+	phys_addr_t src_phys_addr;
+	struct timespec64 start, end;
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	struct device *dma_dev = epf->epc->dev.parent;
+
+	dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+	if (!dst_addr) {
+		dev_err(dev, "Failed to allocate address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
+			       reg->dst_addr, reg->size);
+	if (ret) {
+		dev_err(dev, "Failed to map address\n");
+		reg->status = STATUS_DST_ADDR_INVALID;
+		goto err_addr;
+	}
+
+	buf = kzalloc(reg->size, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto err_map_addr;
+	}
+
+	get_random_bytes(buf, reg->size);
+	reg->checksum = crc32_le(~0, buf, reg->size);
+
+	if (reg->flags & FLAG_USE_DMA) {
+		src_phys_addr = dma_map_single(dma_dev, buf, reg->size,
+					       DMA_TO_DEVICE);
+		if (dma_mapping_error(dma_dev, src_phys_addr)) {
+			dev_err(dev, "Failed to map source buffer addr\n");
+			ret = -ENOMEM;
+			goto err_dma_map;
+		}
+
+		ktime_get_ts64(&start);
+
+		ret = pci_epf_test_data_transfer(epf_test, phys_addr,
+						 src_phys_addr, reg->size,
+						 reg->dst_addr,
+						 DMA_MEM_TO_DEV);
+		if (ret)
+			dev_err(dev, "Data transfer failed\n");
+		ktime_get_ts64(&end);
+
+		dma_unmap_single(dma_dev, src_phys_addr, reg->size,
+				 DMA_TO_DEVICE);
+	} else {
+		ktime_get_ts64(&start);
+		memcpy_toio(dst_addr, buf, reg->size);
+		ktime_get_ts64(&end);
+	}
+
+	pci_epf_test_print_rate(epf_test, "WRITE", reg->size, &start, &end,
+				reg->flags & FLAG_USE_DMA);
+
+	/*
+	 * wait 1ms inorder for the write to complete. Without this delay L3
+	 * error in observed in the host system.
+	 */
+	usleep_range(1000, 2000);
+
+err_dma_map:
+	kfree(buf);
+
+err_map_addr:
+	pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+
+err_addr:
+	pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);
+
+err:
+	if (!ret)
+		reg->status |= STATUS_WRITE_SUCCESS;
+	else
+		reg->status |= STATUS_WRITE_FAIL;
+}
+
+static void pci_epf_test_raise_irq(struct pci_epf_test *epf_test,
+				   struct pci_epf_test_reg *reg)
+{
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	struct pci_epc *epc = epf->epc;
+	u32 status = reg->status | STATUS_IRQ_RAISED;
+	int count;
+
+	/*
+	 * Set the status before raising the IRQ to ensure that the host sees
+	 * the updated value when it gets the IRQ.
+	 */
+	WRITE_ONCE(reg->status, status);
+
+	switch (reg->irq_type) {
+	case IRQ_TYPE_LEGACY:
+		pci_epc_raise_irq(epc, epf->func_no, epf->vfunc_no,
+				  PCI_EPC_IRQ_LEGACY, 0);
+		break;
+	case IRQ_TYPE_MSI:
+		count = pci_epc_get_msi(epc, epf->func_no, epf->vfunc_no);
+		if (reg->irq_number > count || count <= 0) {
+			dev_err(dev, "Invalid MSI IRQ number %d / %d\n",
+				reg->irq_number, count);
+			return;
+		}
+		pci_epc_raise_irq(epc, epf->func_no, epf->vfunc_no,
+				  PCI_EPC_IRQ_MSI, reg->irq_number);
+		break;
+	case IRQ_TYPE_MSIX:
+		count = pci_epc_get_msix(epc, epf->func_no, epf->vfunc_no);
+		if (reg->irq_number > count || count <= 0) {
+			dev_err(dev, "Invalid MSIX IRQ number %d / %d\n",
+				reg->irq_number, count);
+			return;
+		}
+		pci_epc_raise_irq(epc, epf->func_no, epf->vfunc_no,
+				  PCI_EPC_IRQ_MSIX, reg->irq_number);
+		break;
+	default:
+		dev_err(dev, "Failed to raise IRQ, unknown type\n");
+		break;
+	}
+}
+
+static void pci_epf_test_cmd_handler(struct work_struct *work)
+{
+	u32 command;
+	struct pci_epf_test *epf_test = container_of(work, struct pci_epf_test,
+						     cmd_handler.work);
+	struct pci_epf *epf = epf_test->epf;
+	struct device *dev = &epf->dev;
+	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
+	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
+
+	command = READ_ONCE(reg->command);
+	if (!command)
+		goto reset_handler;
+
+	WRITE_ONCE(reg->command, 0);
+	WRITE_ONCE(reg->status, 0);
+
+	if ((READ_ONCE(reg->flags) & FLAG_USE_DMA) &&
+	    !epf_test->dma_supported) {
+		dev_err(dev, "Cannot transfer data using DMA\n");
+		goto reset_handler;
+	}
+
+	if (reg->irq_type > IRQ_TYPE_MSIX) {
+		dev_err(dev, "Failed to detect IRQ type\n");
+		goto reset_handler;
+	}
+
+	switch (command) {
+	case COMMAND_RAISE_LEGACY_IRQ:
+	case COMMAND_RAISE_MSI_IRQ:
+	case COMMAND_RAISE_MSIX_IRQ:
+		pci_epf_test_raise_irq(epf_test, reg);
+		break;
+	case COMMAND_WRITE:
+		pci_epf_test_write(epf_test, reg);
+		pci_epf_test_raise_irq(epf_test, reg);
+		break;
+	case COMMAND_READ:
+		pci_epf_test_read(epf_test, reg);
+		pci_epf_test_raise_irq(epf_test, reg);
+		break;
+	case COMMAND_COPY:
+		pci_epf_test_copy(epf_test, reg);
+		pci_epf_test_raise_irq(epf_test, reg);
+		break;
+	default:
+		dev_err(dev, "Invalid command 0x%x\n", command);
+		break;
+	}
+
+reset_handler:
+	queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
+			   msecs_to_jiffies(1));
+}
+
+static void pci_epf_test_unbind(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct pci_epc *epc = epf->epc;
+	struct pci_epf_bar *epf_bar;
+	int bar;
+
+	cancel_delayed_work(&epf_test->cmd_handler);
+	pci_epf_test_clean_dma_chan(epf_test);
+	for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
+		epf_bar = &epf->bar[bar];
+
+		if (epf_test->reg[bar]) {
+			pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no,
+					  epf_bar);
+			pci_epf_free_space(epf, epf_test->reg[bar], bar,
+					   PRIMARY_INTERFACE);
+		}
+	}
+}
+
+static int pci_epf_test_set_bar(struct pci_epf *epf)
+{
+	int bar, add;
+	int ret;
+	struct pci_epf_bar *epf_bar;
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
+	const struct pci_epc_features *epc_features;
+
+	epc_features = epf_test->epc_features;
+
+	for (bar = 0; bar < PCI_STD_NUM_BARS; bar += add) {
+		epf_bar = &epf->bar[bar];
+		/*
+		 * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64
+		 * if the specific implementation required a 64-bit BAR,
+		 * even if we only requested a 32-bit BAR.
+		 */
+		add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
+
+		if (!!(epc_features->reserved_bar & (1 << bar)))
+			continue;
+
+		ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no,
+				      epf_bar);
+		if (ret) {
+			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;
+		}
+	}
+
+	return 0;
+}
+
+static int pci_epf_test_core_init(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct pci_epf_header *header = epf->header;
+	const struct pci_epc_features *epc_features;
+	struct pci_epc *epc = epf->epc;
+	struct device *dev = &epf->dev;
+	bool msix_capable = false;
+	bool msi_capable = true;
+	int ret;
+
+	epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
+	if (epc_features) {
+		msix_capable = epc_features->msix_capable;
+		msi_capable = epc_features->msi_capable;
+	}
+
+	if (epf->vfunc_no <= 1) {
+		ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, header);
+		if (ret) {
+			dev_err(dev, "Configuration header write failed\n");
+			return ret;
+		}
+	}
+
+	ret = pci_epf_test_set_bar(epf);
+	if (ret)
+		return ret;
+
+	if (msi_capable) {
+		ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
+				      epf->msi_interrupts);
+		if (ret) {
+			dev_err(dev, "MSI configuration failed\n");
+			return ret;
+		}
+	}
+
+	if (msix_capable) {
+		ret = pci_epc_set_msix(epc, epf->func_no, epf->vfunc_no,
+				       epf->msix_interrupts,
+				       epf_test->test_reg_bar,
+				       epf_test->msix_table_offset);
+		if (ret) {
+			dev_err(dev, "MSI-X configuration failed\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int pci_epf_test_link_up(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+
+	queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
+			   msecs_to_jiffies(1));
+
+	return 0;
+}
+
+static const struct pci_epc_event_ops pci_epf_test_event_ops = {
+	.core_init = pci_epf_test_core_init,
+	.link_up = pci_epf_test_link_up,
+};
+
+static int pci_epf_test_alloc_space(struct pci_epf *epf)
+{
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	struct device *dev = &epf->dev;
+	struct pci_epf_bar *epf_bar;
+	size_t msix_table_size = 0;
+	size_t test_reg_bar_size;
+	size_t pba_size = 0;
+	bool msix_capable;
+	void *base;
+	int bar, add;
+	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
+	const struct pci_epc_features *epc_features;
+	size_t test_reg_size;
+
+	epc_features = epf_test->epc_features;
+
+	test_reg_bar_size = ALIGN(sizeof(struct pci_epf_test_reg), 128);
+
+	msix_capable = epc_features->msix_capable;
+	if (msix_capable) {
+		msix_table_size = PCI_MSIX_ENTRY_SIZE * epf->msix_interrupts;
+		epf_test->msix_table_offset = test_reg_bar_size;
+		/* Align to QWORD or 8 Bytes */
+		pba_size = ALIGN(DIV_ROUND_UP(epf->msix_interrupts, 8), 8);
+	}
+	test_reg_size = test_reg_bar_size + msix_table_size + pba_size;
+
+	if (epc_features->bar_fixed_size[test_reg_bar]) {
+		if (test_reg_size > bar_size[test_reg_bar])
+			return -ENOMEM;
+		test_reg_size = bar_size[test_reg_bar];
+	}
+
+	base = pci_epf_alloc_space(epf, test_reg_size, test_reg_bar,
+				   epc_features->align, PRIMARY_INTERFACE);
+	if (!base) {
+		dev_err(dev, "Failed to allocated register space\n");
+		return -ENOMEM;
+	}
+	epf_test->reg[test_reg_bar] = base;
+
+	for (bar = 0; bar < PCI_STD_NUM_BARS; bar += add) {
+		epf_bar = &epf->bar[bar];
+		add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
+
+		if (bar == test_reg_bar)
+			continue;
+
+		if (!!(epc_features->reserved_bar & (1 << bar)))
+			continue;
+
+		base = pci_epf_alloc_space(epf, bar_size[bar], bar,
+					   epc_features->align,
+					   PRIMARY_INTERFACE);
+		if (!base)
+			dev_err(dev, "Failed to allocate space for BAR%d\n",
+				bar);
+		epf_test->reg[bar] = base;
+	}
+
+	return 0;
+}
+
+static void pci_epf_configure_bar(struct pci_epf *epf,
+				  const struct pci_epc_features *epc_features)
+{
+	struct pci_epf_bar *epf_bar;
+	bool bar_fixed_64bit;
+	int i;
+
+	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
+		epf_bar = &epf->bar[i];
+		bar_fixed_64bit = !!(epc_features->bar_fixed_64bit & (1 << i));
+		if (bar_fixed_64bit)
+			epf_bar->flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;
+		if (epc_features->bar_fixed_size[i])
+			bar_size[i] = epc_features->bar_fixed_size[i];
+	}
+}
+
+static int pci_epf_test_bind(struct pci_epf *epf)
+{
+	int ret;
+	struct pci_epf_test *epf_test = epf_get_drvdata(epf);
+	const struct pci_epc_features *epc_features;
+	enum pci_barno test_reg_bar = BAR_0;
+	struct pci_epc *epc = epf->epc;
+	bool linkup_notifier = false;
+	bool core_init_notifier = false;
+
+	if (WARN_ON_ONCE(!epc))
+		return -EINVAL;
+
+	epc_features = pci_epc_get_features(epc, epf->func_no, epf->vfunc_no);
+	if (!epc_features) {
+		dev_err(&epf->dev, "epc_features not implemented\n");
+		return -EOPNOTSUPP;
+	}
+
+	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);
+
+	epf_test->test_reg_bar = test_reg_bar;
+	epf_test->epc_features = epc_features;
+
+	ret = pci_epf_test_alloc_space(epf);
+	if (ret)
+		return ret;
+
+	if (!core_init_notifier) {
+		ret = pci_epf_test_core_init(epf);
+		if (ret)
+			return ret;
+	}
+
+	epf_test->dma_supported = true;
+
+	ret = pci_epf_test_init_dma_chan(epf_test);
+	if (ret)
+		epf_test->dma_supported = false;
+
+	if (!linkup_notifier && !core_init_notifier)
+		queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
+
+	return 0;
+}
+
+static const struct pci_epf_device_id pci_epf_test_ids[] = {
+	{
+		.name = "pci_epf_test",
+	},
+	{},
+};
+
+static int pci_epf_test_probe(struct pci_epf *epf,
+			      const struct pci_epf_device_id *id)
+{
+	struct pci_epf_test *epf_test;
+	struct device *dev = &epf->dev;
+
+	epf_test = devm_kzalloc(dev, sizeof(*epf_test), GFP_KERNEL);
+	if (!epf_test)
+		return -ENOMEM;
+
+	epf->header = &test_header;
+	epf_test->epf = epf;
+
+	INIT_DELAYED_WORK(&epf_test->cmd_handler, pci_epf_test_cmd_handler);
+
+	epf->event_ops = &pci_epf_test_event_ops;
+
+	epf_set_drvdata(epf, epf_test);
+	return 0;
+}
+
+static struct pci_epf_ops ops = {
+	.unbind	= pci_epf_test_unbind,
+	.bind	= pci_epf_test_bind,
+};
+
+static struct pci_epf_driver test_driver = {
+	.driver.name	= "pci_epf_test",
+	.probe		= pci_epf_test_probe,
+	.id_table	= pci_epf_test_ids,
+	.ops		= &ops,
+	.owner		= THIS_MODULE,
+};
+
+static int __init pci_epf_test_init(void)
+{
+	int ret;
+
+	kpcitest_workqueue = alloc_workqueue("kpcitest",
+					     WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+	if (!kpcitest_workqueue) {
+		pr_err("Failed to allocate the kpcitest work queue\n");
+		return -ENOMEM;
+	}
+
+	ret = pci_epf_register_driver(&test_driver);
+	if (ret) {
+		destroy_workqueue(kpcitest_workqueue);
+		pr_err("Failed to register pci epf test driver --> %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(pci_epf_test_init);
+
+static void __exit pci_epf_test_exit(void)
+{
+	if (kpcitest_workqueue)
+		destroy_workqueue(kpcitest_workqueue);
+	pci_epf_unregister_driver(&test_driver);
+}
+module_exit(pci_epf_test_exit);
+
+MODULE_DESCRIPTION("PCI EPF TEST DRIVER");
+MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
new file mode 100644
index 0000000000..3f60128560
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -0,0 +1,1468 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Endpoint Function Driver to implement Non-Transparent Bridge functionality
+ * Between PCI RC and EP
+ *
+ * Copyright (C) 2020 Texas Instruments
+ * Copyright (C) 2022 NXP
+ *
+ * Based on pci-epf-ntb.c
+ * Author: Frank Li <Frank.Li@nxp.com>
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ */
+
+/*
+ * +------------+         +---------------------------------------+
+ * |            |         |                                       |
+ * +------------+         |                        +--------------+
+ * | NTB        |         |                        | NTB          |
+ * | NetDev     |         |                        | NetDev       |
+ * +------------+         |                        +--------------+
+ * | NTB        |         |                        | NTB          |
+ * | Transfer   |         |                        | Transfer     |
+ * +------------+         |                        +--------------+
+ * |            |         |                        |              |
+ * |  PCI NTB   |         |                        |              |
+ * |    EPF     |         |                        |              |
+ * |   Driver   |         |                        | PCI Virtual  |
+ * |            |         +---------------+        | NTB Driver   |
+ * |            |         | PCI EP NTB    |<------>|              |
+ * |            |         |  FN Driver    |        |              |
+ * +------------+         +---------------+        +--------------+
+ * |            |         |               |        |              |
+ * |  PCI Bus   | <-----> |  PCI EP Bus   |        |  Virtual PCI |
+ * |            |  PCI    |               |        |     Bus      |
+ * +------------+         +---------------+--------+--------------+
+ * PCIe Root Port                        PCI EP
+ */
+
+#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>
+#include <linux/ntb.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_DB,
+	BAR_MW0,
+	BAR_MW1,
+	BAR_MW2,
+};
+
+/*
+ * +--------------------------------------------------+ Base
+ * |                                                  |
+ * |                                                  |
+ * |                                                  |
+ * |          Common Control Register                 |
+ * |                                                  |
+ * |                                                  |
+ * |                                                  |
+ * +-----------------------+--------------------------+ Base+spad_offset
+ * |                       |                          |
+ * |    Peer Spad Space    |    Spad Space            |
+ * |                       |                          |
+ * |                       |                          |
+ * +-----------------------+--------------------------+ Base+spad_offset
+ * |                       |                          |     +spad_count * 4
+ * |                       |                          |
+ * |     Spad Space        |   Peer Spad Space        |
+ * |                       |                          |
+ * +-----------------------+--------------------------+
+ *       Virtual PCI             PCIe Endpoint
+ *       NTB Driver               NTB Driver
+ */
+struct epf_ntb_ctrl {
+	u32 command;
+	u32 argument;
+	u16 command_status;
+	u16 link_status;
+	u32 topology;
+	u64 addr;
+	u64 size;
+	u32 num_mws;
+	u32 reserved;
+	u32 spad_offset;
+	u32 spad_count;
+	u32 db_entry_size;
+	u32 db_data[MAX_DB_COUNT];
+	u32 db_offset[MAX_DB_COUNT];
+} __packed;
+
+struct epf_ntb {
+	struct ntb_dev ntb;
+	struct pci_epf *epf;
+	struct config_group group;
+
+	u32 num_mws;
+	u32 db_count;
+	u32 spad_count;
+	u64 mws_size[MAX_MW];
+	u64 db;
+	u32 vbus_number;
+	u16 vntb_pid;
+	u16 vntb_vid;
+
+	bool linkup;
+	u32 spad_size;
+
+	enum pci_barno epf_ntb_bar[6];
+
+	struct epf_ntb_ctrl *reg;
+
+	u32 *epf_db;
+
+	phys_addr_t vpci_mw_phy[MAX_MW];
+	void __iomem *vpci_mw_addr[MAX_MW];
+
+	struct delayed_work cmd_handler;
+};
+
+#define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group)
+#define ntb_ndev(__ntb) container_of(__ntb, struct epf_ntb, ntb)
+
+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 Virtual Host (VHOST)
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @link_up: true or false indicating Link is UP or Down
+ *
+ * Once NTB function in HOST invoke ntb_link_enable(),
+ * this NTB function driver will trigger a link event to VHOST.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_link_up(struct epf_ntb *ntb, bool link_up)
+{
+	if (link_up)
+		ntb->reg->link_status |= LINK_STATUS_UP;
+	else
+		ntb->reg->link_status &= ~LINK_STATUS_UP;
+
+	ntb_link_event(&ntb->ntb);
+	return 0;
+}
+
+/**
+ * epf_ntb_configure_mw() - Configure the Outbound Address Space for VHOST
+ *   to access the memory window of HOST
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @mw: Index of the memory window (either 0, 1, 2 or 3)
+ *
+ *                          EP Outbound Window
+ * +--------+              +-----------+
+ * |        |              |           |
+ * |        |              |           |
+ * |        |              |           |
+ * |        |              |           |
+ * |        |              +-----------+
+ * | Virtual|              | Memory Win|
+ * | NTB    | -----------> |           |
+ * | Driver |              |           |
+ * |        |              +-----------+
+ * |        |              |           |
+ * |        |              |           |
+ * +--------+              +-----------+
+ *  VHOST                   PCI EP
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_configure_mw(struct epf_ntb *ntb, u32 mw)
+{
+	phys_addr_t phys_addr;
+	u8 func_no, vfunc_no;
+	u64 addr, size;
+	int ret = 0;
+
+	phys_addr = ntb->vpci_mw_phy[mw];
+	addr = ntb->reg->addr;
+	size = ntb->reg->size;
+
+	func_no = ntb->epf->func_no;
+	vfunc_no = ntb->epf->vfunc_no;
+
+	ret = pci_epc_map_addr(ntb->epf->epc, func_no, vfunc_no, phys_addr, addr, size);
+	if (ret)
+		dev_err(&ntb->epf->epc->dev,
+			"Failed to map memory window %d address\n", mw);
+	return ret;
+}
+
+/**
+ * epf_ntb_teardown_mw() - Teardown the configured OB ATU
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @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, u32 mw)
+{
+	pci_epc_unmap_addr(ntb->epf->epc,
+			   ntb->epf->func_no,
+			   ntb->epf->vfunc_no,
+			   ntb->vpci_mw_phy[mw]);
+}
+
+/**
+ * epf_ntb_cmd_handler() - Handle commands provided by the NTB HOST
+ * @work: work_struct for the epf_ntb_epc
+ *
+ * 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)
+{
+	struct epf_ntb_ctrl *ctrl;
+	u32 command, argument;
+	struct epf_ntb *ntb;
+	struct device *dev;
+	int ret;
+	int i;
+
+	ntb = container_of(work, struct epf_ntb, cmd_handler.work);
+
+	for (i = 1; i < ntb->db_count; i++) {
+		if (ntb->epf_db[i]) {
+			ntb->db |= 1 << (i - 1);
+			ntb_db_event(&ntb->ntb, i);
+			ntb->epf_db[i] = 0;
+		}
+	}
+
+	ctrl = ntb->reg;
+	command = ctrl->command;
+	if (!command)
+		goto reset_handler;
+	argument = ctrl->argument;
+
+	ctrl->command = 0;
+	ctrl->argument = 0;
+
+	ctrl = ntb->reg;
+	dev = &ntb->epf->dev;
+
+	switch (command) {
+	case COMMAND_CONFIGURE_DOORBELL:
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_TEARDOWN_DOORBELL:
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_CONFIGURE_MW:
+		ret = epf_ntb_configure_mw(ntb, 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, argument);
+		ctrl->command_status = COMMAND_STATUS_OK;
+		break;
+	case COMMAND_LINK_UP:
+		ntb->linkup = true;
+		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;
+	case COMMAND_LINK_DOWN:
+		ntb->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, "UNKNOWN command: %d\n", command);
+		break;
+	}
+
+reset_handler:
+	queue_delayed_work(kpcintb_workqueue, &ntb->cmd_handler,
+			   msecs_to_jiffies(5));
+}
+
+/**
+ * epf_ntb_config_sspad_bar_clear() - Clear Config + Self scratchpad BAR
+ * @ntb: EPC associated with one of the HOST which holds peer's outbound
+ *	 address.
+ *
+ * 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 VHOST's peer
+ * scratchpad is HOST's self scratchpad.
+ *
+ * Returns: void
+ */
+static void epf_ntb_config_sspad_bar_clear(struct epf_ntb *ntb)
+{
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+
+	barno = ntb->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb->epf->bar[barno];
+
+	pci_epc_clear_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar);
+}
+
+/**
+ * epf_ntb_config_sspad_bar_set() - Set Config + Self scratchpad BAR
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Map BAR0 of EP CONTROLLER which contains the VHOST's config and
+ * self scratchpad region.
+ *
+ * Please note the self scratchpad region and config region is combined to
+ * a single region and mapped using the same BAR.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_config_sspad_bar_set(struct epf_ntb *ntb)
+{
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+	u8 func_no, vfunc_no;
+	struct device *dev;
+	int ret;
+
+	dev = &ntb->epf->dev;
+	func_no = ntb->epf->func_no;
+	vfunc_no = ntb->epf->vfunc_no;
+	barno = ntb->epf_ntb_bar[BAR_CONFIG];
+	epf_bar = &ntb->epf->bar[barno];
+
+	ret = pci_epc_set_bar(ntb->epf->epc, func_no, vfunc_no, epf_bar);
+	if (ret) {
+		dev_err(dev, "inft: Config/Status/SPAD BAR set failed\n");
+		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 HOST and VHOST
+ */
+static void epf_ntb_config_spad_bar_free(struct epf_ntb *ntb)
+{
+	enum pci_barno barno;
+
+	barno = ntb->epf_ntb_bar[BAR_CONFIG];
+	pci_epf_free_space(ntb->epf, ntb->reg, barno, 0);
+}
+
+/**
+ * epf_ntb_config_spad_bar_alloc() - Allocate memory for config + scratchpad
+ *   region
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * 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.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb)
+{
+	size_t align;
+	enum pci_barno barno;
+	struct epf_ntb_ctrl *ctrl;
+	u32 spad_size, ctrl_size;
+	u64 size;
+	struct pci_epf *epf = ntb->epf;
+	struct device *dev = &epf->dev;
+	u32 spad_count;
+	void *base;
+	int i;
+	const struct pci_epc_features *epc_features = pci_epc_get_features(epf->epc,
+								epf->func_no,
+								epf->vfunc_no);
+	barno = ntb->epf_ntb_bar[BAR_CONFIG];
+	size = epc_features->bar_fixed_size[barno];
+	align = epc_features->align;
+
+	if ((!IS_ALIGNED(size, align)))
+		return -EINVAL;
+
+	spad_count = ntb->spad_count;
+
+	ctrl_size = sizeof(struct epf_ntb_ctrl);
+	spad_size = 2 * spad_count * sizeof(u32);
+
+	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 (!size)
+		size = ctrl_size + spad_size;
+	else if (size < ctrl_size + spad_size)
+		return -EINVAL;
+
+	base = pci_epf_alloc_space(epf, size, barno, align, 0);
+	if (!base) {
+		dev_err(dev, "Config/Status/SPAD alloc region fail\n");
+		return -ENOMEM;
+	}
+
+	ntb->reg = base;
+
+	ctrl = ntb->reg;
+	ctrl->spad_offset = ctrl_size;
+
+	ctrl->spad_count = spad_count;
+	ctrl->num_mws = ntb->num_mws;
+	ntb->spad_size = spad_size;
+
+	ctrl->db_entry_size = sizeof(u32);
+
+	for (i = 0; i < ntb->db_count; i++) {
+		ntb->reg->db_data[i] = 1 + i;
+		ntb->reg->db_offset[i] = 0;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_configure_interrupt() - Configure MSI/MSI-X capability
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Configure MSI/MSI-X capability for each interface with number of
+ * interrupts equal to "db_count" configfs entry.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	struct device *dev;
+	u32 db_count;
+	int ret;
+
+	dev = &ntb->epf->dev;
+
+	epc_features = pci_epc_get_features(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no);
+
+	if (!(epc_features->msix_capable || epc_features->msi_capable)) {
+		dev_err(dev, "MSI or MSI-X is required for doorbell\n");
+		return -EINVAL;
+	}
+
+	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;
+
+	if (epc_features->msi_capable) {
+		ret = pci_epc_set_msi(ntb->epf->epc,
+				      ntb->epf->func_no,
+				      ntb->epf->vfunc_no,
+				      16);
+		if (ret) {
+			dev_err(dev, "MSI configuration failed\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_db_bar_init() - Configure Doorbell window BARs
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	u32 align;
+	struct device *dev = &ntb->epf->dev;
+	int ret;
+	struct pci_epf_bar *epf_bar;
+	void __iomem *mw_addr;
+	enum pci_barno barno;
+	size_t size = sizeof(u32) * ntb->db_count;
+
+	epc_features = pci_epc_get_features(ntb->epf->epc,
+					    ntb->epf->func_no,
+					    ntb->epf->vfunc_no);
+	align = epc_features->align;
+
+	if (size < 128)
+		size = 128;
+
+	if (align)
+		size = ALIGN(size, align);
+	else
+		size = roundup_pow_of_two(size);
+
+	barno = ntb->epf_ntb_bar[BAR_DB];
+
+	mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
+	if (!mw_addr) {
+		dev_err(dev, "Failed to allocate OB address\n");
+		return -ENOMEM;
+	}
+
+	ntb->epf_db = mw_addr;
+
+	epf_bar = &ntb->epf->bar[barno];
+
+	ret = pci_epc_set_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar);
+	if (ret) {
+		dev_err(dev, "Doorbell BAR set failed\n");
+			goto err_alloc_peer_mem;
+	}
+	return ret;
+
+err_alloc_peer_mem:
+	pci_epf_free_space(ntb->epf, mw_addr, barno, 0);
+	return -1;
+}
+
+static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb, int num_mws);
+
+/**
+ * epf_ntb_db_bar_clear() - Clear doorbell BAR and free memory
+ *   allocated in peer's outbound address space
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ */
+static void epf_ntb_db_bar_clear(struct epf_ntb *ntb)
+{
+	enum pci_barno barno;
+
+	barno = ntb->epf_ntb_bar[BAR_DB];
+	pci_epf_free_space(ntb->epf, ntb->epf_db, barno, 0);
+	pci_epc_clear_bar(ntb->epf->epc,
+			  ntb->epf->func_no,
+			  ntb->epf->vfunc_no,
+			  &ntb->epf->bar[barno]);
+}
+
+/**
+ * epf_ntb_mw_bar_init() - Configure Memory window BARs
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_mw_bar_init(struct epf_ntb *ntb)
+{
+	int ret = 0;
+	int i;
+	u64 size;
+	enum pci_barno barno;
+	struct device *dev = &ntb->epf->dev;
+
+	for (i = 0; i < ntb->num_mws; i++) {
+		size = ntb->mws_size[i];
+		barno = ntb->epf_ntb_bar[BAR_MW0 + i];
+
+		ntb->epf->bar[barno].barno = barno;
+		ntb->epf->bar[barno].size = size;
+		ntb->epf->bar[barno].addr = NULL;
+		ntb->epf->bar[barno].phys_addr = 0;
+		ntb->epf->bar[barno].flags |= upper_32_bits(size) ?
+				PCI_BASE_ADDRESS_MEM_TYPE_64 :
+				PCI_BASE_ADDRESS_MEM_TYPE_32;
+
+		ret = pci_epc_set_bar(ntb->epf->epc,
+				      ntb->epf->func_no,
+				      ntb->epf->vfunc_no,
+				      &ntb->epf->bar[barno]);
+		if (ret) {
+			dev_err(dev, "MW set failed\n");
+			goto err_alloc_mem;
+		}
+
+		/* Allocate EPC outbound memory windows to vpci vntb device */
+		ntb->vpci_mw_addr[i] = pci_epc_mem_alloc_addr(ntb->epf->epc,
+							      &ntb->vpci_mw_phy[i],
+							      size);
+		if (!ntb->vpci_mw_addr[i]) {
+			ret = -ENOMEM;
+			dev_err(dev, "Failed to allocate source address\n");
+			goto err_set_bar;
+		}
+	}
+
+	return ret;
+
+err_set_bar:
+	pci_epc_clear_bar(ntb->epf->epc,
+			  ntb->epf->func_no,
+			  ntb->epf->vfunc_no,
+			  &ntb->epf->bar[barno]);
+err_alloc_mem:
+	epf_ntb_mw_bar_clear(ntb, i);
+	return ret;
+}
+
+/**
+ * epf_ntb_mw_bar_clear() - Clear Memory window BARs
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ * @num_mws: the number of Memory window BARs that to be cleared
+ */
+static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb, int num_mws)
+{
+	enum pci_barno barno;
+	int i;
+
+	for (i = 0; i < num_mws; i++) {
+		barno = ntb->epf_ntb_bar[BAR_MW0 + i];
+		pci_epc_clear_bar(ntb->epf->epc,
+				  ntb->epf->func_no,
+				  ntb->epf->vfunc_no,
+				  &ntb->epf->bar[barno]);
+
+		pci_epc_mem_free_addr(ntb->epf->epc,
+				      ntb->vpci_mw_phy[i],
+				      ntb->vpci_mw_addr[i],
+				      ntb->mws_size[i]);
+	}
+}
+
+/**
+ * epf_ntb_epc_destroy() - Cleanup NTB EPC interface
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Wrapper for epf_ntb_epc_destroy_interface() to cleanup all the NTB interfaces
+ */
+static void epf_ntb_epc_destroy(struct epf_ntb *ntb)
+{
+	pci_epc_remove_epf(ntb->epf->epc, ntb->epf, 0);
+	pci_epc_put(ntb->epf->epc);
+}
+
+/**
+ * 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 HOST and VHOST
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_init_epc_bar(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	enum pci_barno barno;
+	enum epf_ntb_bar bar;
+	struct device *dev;
+	u32 num_mws;
+	int i;
+
+	barno = BAR_0;
+	num_mws = ntb->num_mws;
+	dev = &ntb->epf->dev;
+	epc_features = pci_epc_get_features(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no);
+
+	/* These are required BARs which are mandatory for NTB functionality */
+	for (bar = BAR_CONFIG; bar <= BAR_MW0; bar++, barno++) {
+		barno = pci_epc_get_next_free_bar(epc_features, barno);
+		if (barno < 0) {
+			dev_err(dev, "Fail to get NTB function BAR\n");
+			return barno;
+		}
+		ntb->epf_ntb_bar[bar] = barno;
+	}
+
+	/* These are optional BARs which don't impact NTB functionality */
+	for (bar = BAR_MW1, 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->epf_ntb_bar[bar] = barno;
+	}
+
+	return 0;
+}
+
+/**
+ * epf_ntb_epc_init() - Initialize NTB interface
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * 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.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_epc_init(struct epf_ntb *ntb)
+{
+	u8 func_no, vfunc_no;
+	struct pci_epc *epc;
+	struct pci_epf *epf;
+	struct device *dev;
+	int ret;
+
+	epf = ntb->epf;
+	dev = &epf->dev;
+	epc = epf->epc;
+	func_no = ntb->epf->func_no;
+	vfunc_no = ntb->epf->vfunc_no;
+
+	ret = epf_ntb_config_sspad_bar_set(ntb);
+	if (ret) {
+		dev_err(dev, "Config/self SPAD BAR init failed");
+		return ret;
+	}
+
+	ret = epf_ntb_configure_interrupt(ntb);
+	if (ret) {
+		dev_err(dev, "Interrupt configuration failed\n");
+		goto err_config_interrupt;
+	}
+
+	ret = epf_ntb_db_bar_init(ntb);
+	if (ret) {
+		dev_err(dev, "DB BAR init failed\n");
+		goto err_db_bar_init;
+	}
+
+	ret = epf_ntb_mw_bar_init(ntb);
+	if (ret) {
+		dev_err(dev, "MW BAR init failed\n");
+		goto err_mw_bar_init;
+	}
+
+	if (vfunc_no <= 1) {
+		ret = pci_epc_write_header(epc, func_no, vfunc_no, epf->header);
+		if (ret) {
+			dev_err(dev, "Configuration header write failed\n");
+			goto err_write_header;
+		}
+	}
+
+	INIT_DELAYED_WORK(&ntb->cmd_handler, epf_ntb_cmd_handler);
+	queue_work(kpcintb_workqueue, &ntb->cmd_handler.work);
+
+	return 0;
+
+err_write_header:
+	epf_ntb_mw_bar_clear(ntb, ntb->num_mws);
+err_mw_bar_init:
+	epf_ntb_db_bar_clear(ntb);
+err_db_bar_init:
+err_config_interrupt:
+	epf_ntb_config_sspad_bar_clear(ntb);
+
+	return ret;
+}
+
+
+/**
+ * epf_ntb_epc_cleanup() - Cleanup all NTB interfaces
+ * @ntb: NTB device that facilitates communication between HOST and VHOST
+ *
+ * Wrapper to cleanup all NTB interfaces.
+ */
+static void epf_ntb_epc_cleanup(struct epf_ntb *ntb)
+{
+	epf_ntb_db_bar_clear(ntb);
+	epf_ntb_mw_bar_clear(ntb, ntb->num_mws);
+}
+
+#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);			\
+	struct device *dev = &ntb->epf->dev;				\
+	int win_no;							\
+									\
+	if (sscanf(#_name, "mw%d", &win_no) != 1)			\
+		return -EINVAL;						\
+									\
+	if (win_no <= 0 || win_no > ntb->num_mws) {			\
+		dev_err(dev, "Invalid num_nws: %d value\n", ntb->num_mws); \
+		return -EINVAL;						\
+	}								\
+									\
+	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 (win_no <= 0 || win_no > ntb->num_mws) {			\
+		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_R(vbus_number)
+EPF_NTB_W(vbus_number)
+EPF_NTB_R(vntb_pid)
+EPF_NTB_W(vntb_pid)
+EPF_NTB_R(vntb_vid)
+EPF_NTB_W(vntb_vid)
+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);
+CONFIGFS_ATTR(epf_ntb_, vbus_number);
+CONFIGFS_ATTR(epf_ntb_, vntb_pid);
+CONFIGFS_ATTR(epf_ntb_, vntb_vid);
+
+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,
+	&epf_ntb_attr_vbus_number,
+	&epf_ntb_attr_vntb_pid,
+	&epf_ntb_attr_vntb_vid,
+	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
+ * @group: A pointer to the config_group structure referencing a group of
+ *	   config_items of a specific type that belong to a specific sub-system.
+ *
+ * Add configfs directory specific to NTB. This directory will hold
+ * NTB specific properties like db_count, spad_count, num_mws etc.,
+ *
+ * Returns: Pointer to config_group
+ */
+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;
+}
+
+/*==== virtual PCI bus driver, which only load virtual NTB PCI driver ====*/
+
+static u32 pci_space[] = {
+	0xffffffff,	/* Device ID, Vendor ID */
+	0,		/* Status, Command */
+	0xffffffff,	/* Base Class, Subclass, Prog Intf, Revision ID */
+	0x40,		/* BIST, Header Type, Latency Timer, Cache Line Size */
+	0,		/* BAR 0 */
+	0,		/* BAR 1 */
+	0,		/* BAR 2 */
+	0,		/* BAR 3 */
+	0,		/* BAR 4 */
+	0,		/* BAR 5 */
+	0,		/* Cardbus CIS Pointer */
+	0,		/* Subsystem ID, Subsystem Vendor ID */
+	0,		/* ROM Base Address */
+	0,		/* Reserved, Capabilities Pointer */
+	0,		/* Reserved */
+	0,		/* Max_Lat, Min_Gnt, Interrupt Pin, Interrupt Line */
+};
+
+static int pci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val)
+{
+	if (devfn == 0) {
+		memcpy(val, ((u8 *)pci_space) + where, size);
+		return PCIBIOS_SUCCESSFUL;
+	}
+	return PCIBIOS_DEVICE_NOT_FOUND;
+}
+
+static int pci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val)
+{
+	return 0;
+}
+
+static struct pci_ops vpci_ops = {
+	.read = pci_read,
+	.write = pci_write,
+};
+
+static int vpci_scan_bus(void *sysdata)
+{
+	struct pci_bus *vpci_bus;
+	struct epf_ntb *ndev = sysdata;
+
+	vpci_bus = pci_scan_bus(ndev->vbus_number, &vpci_ops, sysdata);
+	if (vpci_bus)
+		pr_err("create pci bus\n");
+
+	pci_bus_add_devices(vpci_bus);
+
+	return 0;
+}
+
+/*==================== Virtual PCIe NTB driver ==========================*/
+
+static int vntb_epf_mw_count(struct ntb_dev *ntb, int pidx)
+{
+	struct epf_ntb *ndev = ntb_ndev(ntb);
+
+	return ndev->num_mws;
+}
+
+static int vntb_epf_spad_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->spad_count;
+}
+
+static int vntb_epf_peer_mw_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->num_mws;
+}
+
+static u64 vntb_epf_db_valid_mask(struct ntb_dev *ntb)
+{
+	return BIT_ULL(ntb_ndev(ntb)->db_count) - 1;
+}
+
+static int vntb_epf_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	return 0;
+}
+
+static int vntb_epf_mw_set_trans(struct ntb_dev *ndev, int pidx, int idx,
+		dma_addr_t addr, resource_size_t size)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	struct pci_epf_bar *epf_bar;
+	enum pci_barno barno;
+	int ret;
+	struct device *dev;
+
+	dev = &ntb->ntb.dev;
+	barno = ntb->epf_ntb_bar[BAR_MW0 + idx];
+	epf_bar = &ntb->epf->bar[barno];
+	epf_bar->phys_addr = addr;
+	epf_bar->barno = barno;
+	epf_bar->size = size;
+
+	ret = pci_epc_set_bar(ntb->epf->epc, 0, 0, epf_bar);
+	if (ret) {
+		dev_err(dev, "failure set mw trans\n");
+		return ret;
+	}
+	return 0;
+}
+
+static int vntb_epf_mw_clear_trans(struct ntb_dev *ntb, int pidx, int idx)
+{
+	return 0;
+}
+
+static int vntb_epf_peer_mw_get_addr(struct ntb_dev *ndev, int idx,
+				phys_addr_t *base, resource_size_t *size)
+{
+
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	if (base)
+		*base = ntb->vpci_mw_phy[idx];
+
+	if (size)
+		*size = ntb->mws_size[idx];
+
+	return 0;
+}
+
+static int vntb_epf_link_enable(struct ntb_dev *ntb,
+			enum ntb_speed max_speed,
+			enum ntb_width max_width)
+{
+	return 0;
+}
+
+static u32 vntb_epf_spad_read(struct ntb_dev *ndev, int idx)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	int off = ntb->reg->spad_offset, ct = ntb->reg->spad_count * sizeof(u32);
+	u32 val;
+	void __iomem *base = (void __iomem *)ntb->reg;
+
+	val = readl(base + off + ct + idx * sizeof(u32));
+	return val;
+}
+
+static int vntb_epf_spad_write(struct ntb_dev *ndev, int idx, u32 val)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	struct epf_ntb_ctrl *ctrl = ntb->reg;
+	int off = ctrl->spad_offset, ct = ctrl->spad_count * sizeof(u32);
+	void __iomem *base = (void __iomem *)ntb->reg;
+
+	writel(val, base + off + ct + idx * sizeof(u32));
+	return 0;
+}
+
+static u32 vntb_epf_peer_spad_read(struct ntb_dev *ndev, int pidx, int idx)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	struct epf_ntb_ctrl *ctrl = ntb->reg;
+	int off = ctrl->spad_offset;
+	void __iomem *base = (void __iomem *)ntb->reg;
+	u32 val;
+
+	val = readl(base + off + idx * sizeof(u32));
+	return val;
+}
+
+static int vntb_epf_peer_spad_write(struct ntb_dev *ndev, int pidx, int idx, u32 val)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	struct epf_ntb_ctrl *ctrl = ntb->reg;
+	int off = ctrl->spad_offset;
+	void __iomem *base = (void __iomem *)ntb->reg;
+
+	writel(val, base + off + idx * sizeof(u32));
+	return 0;
+}
+
+static int vntb_epf_peer_db_set(struct ntb_dev *ndev, u64 db_bits)
+{
+	u32 interrupt_num = ffs(db_bits) + 1;
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+	u8 func_no, vfunc_no;
+	int ret;
+
+	func_no = ntb->epf->func_no;
+	vfunc_no = ntb->epf->vfunc_no;
+
+	ret = pci_epc_raise_irq(ntb->epf->epc,
+				func_no,
+				vfunc_no,
+				PCI_EPC_IRQ_MSI,
+				interrupt_num + 1);
+	if (ret)
+		dev_err(&ntb->ntb.dev, "Failed to raise IRQ\n");
+
+	return ret;
+}
+
+static u64 vntb_epf_db_read(struct ntb_dev *ndev)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	return ntb->db;
+}
+
+static int vntb_epf_mw_get_align(struct ntb_dev *ndev, int pidx, int idx,
+			resource_size_t *addr_align,
+			resource_size_t *size_align,
+			resource_size_t *size_max)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	if (addr_align)
+		*addr_align = SZ_4K;
+
+	if (size_align)
+		*size_align = 1;
+
+	if (size_max)
+		*size_max = ntb->mws_size[idx];
+
+	return 0;
+}
+
+static u64 vntb_epf_link_is_up(struct ntb_dev *ndev,
+			enum ntb_speed *speed,
+			enum ntb_width *width)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	return ntb->reg->link_status;
+}
+
+static int vntb_epf_db_clear_mask(struct ntb_dev *ndev, u64 db_bits)
+{
+	return 0;
+}
+
+static int vntb_epf_db_clear(struct ntb_dev *ndev, u64 db_bits)
+{
+	struct epf_ntb *ntb = ntb_ndev(ndev);
+
+	ntb->db &= ~db_bits;
+	return 0;
+}
+
+static int vntb_epf_link_disable(struct ntb_dev *ntb)
+{
+	return 0;
+}
+
+static const struct ntb_dev_ops vntb_epf_ops = {
+	.mw_count		= vntb_epf_mw_count,
+	.spad_count		= vntb_epf_spad_count,
+	.peer_mw_count		= vntb_epf_peer_mw_count,
+	.db_valid_mask		= vntb_epf_db_valid_mask,
+	.db_set_mask		= vntb_epf_db_set_mask,
+	.mw_set_trans		= vntb_epf_mw_set_trans,
+	.mw_clear_trans		= vntb_epf_mw_clear_trans,
+	.peer_mw_get_addr	= vntb_epf_peer_mw_get_addr,
+	.link_enable		= vntb_epf_link_enable,
+	.spad_read		= vntb_epf_spad_read,
+	.spad_write		= vntb_epf_spad_write,
+	.peer_spad_read		= vntb_epf_peer_spad_read,
+	.peer_spad_write	= vntb_epf_peer_spad_write,
+	.peer_db_set		= vntb_epf_peer_db_set,
+	.db_read		= vntb_epf_db_read,
+	.mw_get_align		= vntb_epf_mw_get_align,
+	.link_is_up		= vntb_epf_link_is_up,
+	.db_clear_mask		= vntb_epf_db_clear_mask,
+	.db_clear		= vntb_epf_db_clear,
+	.link_disable		= vntb_epf_link_disable,
+};
+
+static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	int ret;
+	struct epf_ntb *ndev = (struct epf_ntb *)pdev->sysdata;
+	struct device *dev = &pdev->dev;
+
+	ndev->ntb.pdev = pdev;
+	ndev->ntb.topo = NTB_TOPO_NONE;
+	ndev->ntb.ops =  &vntb_epf_ops;
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(dev, "Cannot set DMA mask\n");
+		return -EINVAL;
+	}
+
+	ret = ntb_register_device(&ndev->ntb);
+	if (ret) {
+		dev_err(dev, "Failed to register NTB device\n");
+		goto err_register_dev;
+	}
+
+	dev_dbg(dev, "PCI Virtual NTB driver loaded\n");
+	return 0;
+
+err_register_dev:
+	put_device(&ndev->ntb.dev);
+	return -EINVAL;
+}
+
+static struct pci_device_id pci_vntb_table[] = {
+	{
+		PCI_DEVICE(0xffff, 0xffff),
+	},
+	{},
+};
+
+static struct pci_driver vntb_pci_driver = {
+	.name           = "pci-vntb",
+	.id_table       = pci_vntb_table,
+	.probe          = pci_vntb_probe,
+};
+
+/* ============ PCIe EPF Driver Bind ====================*/
+
+/**
+ * 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.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+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;
+	}
+
+	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(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);
+
+	pci_space[0] = (ntb->vntb_pid << 16) | ntb->vntb_vid;
+	pci_vntb_table[0].vendor = ntb->vntb_vid;
+	pci_vntb_table[0].device = ntb->vntb_pid;
+
+	ret = pci_register_driver(&vntb_pci_driver);
+	if (ret) {
+		dev_err(dev, "failure register vntb pci driver\n");
+		goto err_bar_alloc;
+	}
+
+	vpci_scan_bus(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);
+
+	pci_unregister_driver(&vntb_pci_driver);
+}
+
+// EPF driver probe
+static struct pci_epf_ops epf_ntb_ops = {
+	.bind   = epf_ntb_bind,
+	.unbind = epf_ntb_unbind,
+	.add_cfs = epf_ntb_add_cfs,
+};
+
+/**
+ * epf_ntb_probe() - Probe NTB function driver
+ * @epf: NTB endpoint function device
+ * @id: NTB endpoint function device ID
+ *
+ * Probe NTB function driver when endpoint function bus detects a NTB
+ * endpoint function.
+ *
+ * Returns: Zero for success, or an error code in case of failure
+ */
+static int epf_ntb_probe(struct pci_epf *epf,
+			 const struct pci_epf_device_id *id)
+{
+	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;
+	ntb->vbus_number = 0xff;
+	epf_set_drvdata(epf, ntb);
+
+	dev_info(dev, "pci-ep epf driver loaded\n");
+	return 0;
+}
+
+static const struct pci_epf_device_id epf_ntb_ids[] = {
+	{
+		.name = "pci_epf_vntb",
+	},
+	{},
+};
+
+static struct pci_epf_driver epf_ntb_driver = {
+	.driver.name    = "pci_epf_vntb",
+	.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("Frank Li <Frank.li@nxp.com>");
+MODULE_LICENSE("GPL v2");