Merge branch 'ntb-next' of https://github.com/jonmason/ntb.git

13 files changed, 2598 insertions, 35 deletions

diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst
index 38ea1f604b6d..4d2333e7ae06 100644
--- a/Documentation/PCI/endpoint/index.rst
+++ b/Documentation/PCI/endpoint/index.rst
@@ -13,6 +13,8 @@ PCI Endpoint Framework
    pci-test-howto
    pci-ntb-function
    pci-ntb-howto
+   pci-vntb-function
+   pci-vntb-howto
 
    function/binding/pci-test
    function/binding/pci-ntb
diff --git a/Documentation/PCI/endpoint/pci-vntb-function.rst b/Documentation/PCI/endpoint/pci-vntb-function.rst
new file mode 100644
index 000000000000..cad8013e8839
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-vntb-function.rst
@@ -0,0 +1,126 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+PCI vNTB Function
+=================
+
+:Author: Frank Li <Frank.Li@nxp.com>
+
+The difference between PCI NTB function and PCI vNTB function is
+
+PCI NTB function need at two endpoint instances and connect HOST1
+and HOST2.
+
+PCI vNTB function only use one host and one endpoint(EP), use NTB
+connect EP and PCI host
+
+.. code-block:: text
+
+
+  +------------+         +---------------------------------------+
+  |            |         |                                       |
+  +------------+         |                        +--------------+
+  | 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      |
+  +------------+         +---------------+--------+--------------+
+      PCI RC                        PCI EP
+
+Constructs used for Implementing vNTB
+=====================================
+
+	1) Config Region
+	2) Self Scratchpad Registers
+	3) Peer Scratchpad Registers
+	4) Doorbell (DB) Registers
+	5) Memory Window (MW)
+
+
+Config Region:
+--------------
+
+It is same as PCI NTB Function driver
+
+Scratchpad Registers:
+---------------------
+
+  It is appended after Config region.
+
+  +--------------------------------------------------+ Base
+  |                                                  |
+  |                                                  |
+  |                                                  |
+  |          Common Config Register                  |
+  |                                                  |
+  |                                                  |
+  |                                                  |
+  +-----------------------+--------------------------+ Base + span_offset
+  |                       |                          |
+  |    Peer Span Space    |    Span Space            |
+  |                       |                          |
+  |                       |                          |
+  +-----------------------+--------------------------+ Base + span_offset
+  |                       |                          |      + span_count * 4
+  |                       |                          |
+  |     Span Space        |   Peer Span Space        |
+  |                       |                          |
+  +-----------------------+--------------------------+
+        Virtual PCI             Pcie Endpoint
+        NTB Driver               NTB Driver
+
+
+Doorbell Registers:
+-------------------
+
+  Doorbell Registers are used by the hosts to interrupt each other.
+
+Memory Window:
+--------------
+
+  Actual transfer of data between the two hosts will happen using the
+  memory window.
+
+Modeling Constructs:
+====================
+
+32-bit BARs.
+
+======  ===============
+BAR NO  CONSTRUCTS USED
+======  ===============
+BAR0    Config Region
+BAR1    Doorbell
+BAR2    Memory Window 1
+BAR3    Memory Window 2
+BAR4    Memory Window 3
+BAR5    Memory Window 4
+======  ===============
+
+64-bit BARs.
+
+======  ===============================
+BAR NO  CONSTRUCTS USED
+======  ===============================
+BAR0    Config Region + Scratchpad
+BAR1
+BAR2    Doorbell
+BAR3
+BAR4    Memory Window 1
+BAR5
+======  ===============================
+
+
diff --git a/Documentation/PCI/endpoint/pci-vntb-howto.rst b/Documentation/PCI/endpoint/pci-vntb-howto.rst
new file mode 100644
index 000000000000..b4a679144692
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-vntb-howto.rst
@@ -0,0 +1,161 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================================================================
+PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide
+===================================================================
+
+:Author: Frank Li <Frank.Li@nxp.com>
+
+This document is a guide to help users use pci-epf-vntb function driver
+and ntb_hw_epf host driver for NTB functionality. The list of steps to
+be followed in the host side and EP side is given below. For the hardware
+configuration and internals of NTB using configurable endpoints see
+Documentation/PCI/endpoint/pci-vntb-function.rst
+
+Endpoint Device
+===============
+
+Endpoint Controller Devices
+---------------------------
+
+To find the list of endpoint controller devices in the system::
+
+        # ls /sys/class/pci_epc/
+          5f010000.pcie_ep
+
+If PCI_ENDPOINT_CONFIGFS is enabled::
+
+        # ls /sys/kernel/config/pci_ep/controllers
+          5f010000.pcie_ep
+
+Endpoint Function Drivers
+-------------------------
+
+To find the list of endpoint function drivers in the system::
+
+	# ls /sys/bus/pci-epf/drivers
+	pci_epf_ntb  pci_epf_test  pci_epf_vntb
+
+If PCI_ENDPOINT_CONFIGFS is enabled::
+
+	# ls /sys/kernel/config/pci_ep/functions
+	pci_epf_ntb  pci_epf_test  pci_epf_vntb
+
+
+Creating pci-epf-vntb Device
+----------------------------
+
+PCI endpoint function device can be created using the configfs. To create
+pci-epf-vntb device, the following commands can be used::
+
+	# mount -t configfs none /sys/kernel/config
+	# cd /sys/kernel/config/pci_ep/
+	# mkdir functions/pci_epf_vntb/func1
+
+The "mkdir func1" above creates the pci-epf-ntb function device that will
+be probed by pci_epf_vntb driver.
+
+The PCI endpoint framework populates the directory with the following
+configurable fields::
+
+	# ls functions/pci_epf_ntb/func1
+	baseclass_code    deviceid          msi_interrupts    pci-epf-ntb.0
+	progif_code       secondary         subsys_id         vendorid
+	cache_line_size   interrupt_pin     msix_interrupts   primary
+	revid             subclass_code     subsys_vendor_id
+
+The PCI endpoint function driver populates these entries with default values
+when the device is bound to the driver. The pci-epf-vntb driver populates
+vendorid with 0xffff and interrupt_pin with 0x0001::
+
+	# cat functions/pci_epf_vntb/func1/vendorid
+	0xffff
+	# cat functions/pci_epf_vntb/func1/interrupt_pin
+	0x0001
+
+
+Configuring pci-epf-vntb Device
+-------------------------------
+
+The user can configure the pci-epf-vntb device using its configfs entry. In order
+to change the vendorid and the deviceid, the following
+commands can be used::
+
+	# echo 0x1957 > functions/pci_epf_vntb/func1/vendorid
+	# echo 0x0809 > functions/pci_epf_vntb/func1/deviceid
+
+In order to configure NTB specific attributes, a new sub-directory to func1
+should be created::
+
+	# mkdir functions/pci_epf_vntb/func1/pci_epf_vntb.0/
+
+The NTB function driver will populate this directory with various attributes
+that can be configured by the user::
+
+	# ls functions/pci_epf_vntb/func1/pci_epf_vntb.0/
+	db_count    mw1         mw2         mw3         mw4         num_mws
+	spad_count
+
+A sample configuration for NTB function is given below::
+
+	# echo 4 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/db_count
+	# echo 128 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/spad_count
+	# echo 1 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/num_mws
+	# echo 0x100000 > functions/pci_epf_vntb/func1/pci_epf_vntb.0/mw1
+
+Binding pci-epf-ntb Device to EP Controller
+--------------------------------------------
+
+NTB function device should be attached to PCI endpoint controllers
+connected to the host.
+
+	# ln -s controllers/5f010000.pcie_ep functions/pci-epf-ntb/func1/primary
+
+Once the above step is completed, the PCI endpoint controllers are ready to
+establish a link with the host.
+
+
+Start the Link
+--------------
+
+In order for the endpoint device to establish a link with the host, the _start_
+field should be populated with '1'. For NTB, both the PCI endpoint controllers
+should establish link with the host (imx8 don't need this steps)::
+
+	# echo 1 > controllers/5f010000.pcie_ep/start
+
+RootComplex Device
+==================
+
+lspci Output at Host side
+------------------------
+
+Note that the devices listed here correspond to the values populated in
+"Creating pci-epf-ntb Device" section above::
+
+	# lspci
+        00:00.0 PCI bridge: Freescale Semiconductor Inc Device 0000 (rev 01)
+        01:00.0 RAM memory: Freescale Semiconductor Inc Device 0809
+
+Endpoint Device / Virtual PCI bus
+=================================
+
+lspci Output at EP Side / Virtual PCI bus
+-----------------------------------------
+
+Note that the devices listed here correspond to the values populated in
+"Creating pci-epf-ntb Device" section above::
+
+        # lspci
+        10:00.0 Unassigned class [ffff]: Dawicontrol Computersysteme GmbH Device 1234 (rev ff)
+
+Using ntb_hw_epf Device
+-----------------------
+
+The host side software follows the standard NTB software architecture in Linux.
+All the existing client side NTB utilities like NTB Transport Client and NTB
+Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB
+function device.
+
+For more information on NTB see
+:doc:`Non-Transparent Bridge <../../driver-api/ntb>`
diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index b019755e4e21..3ece49cb18ff 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -45,7 +45,6 @@
 
 #define NTB_EPF_MIN_DB_COUNT	3
 #define NTB_EPF_MAX_DB_COUNT	31
-#define NTB_EPF_MW_OFFSET	2
 
 #define NTB_EPF_COMMAND_TIMEOUT	1000 /* 1 Sec */
 
@@ -67,6 +66,7 @@ struct ntb_epf_dev {
 	enum pci_barno ctrl_reg_bar;
 	enum pci_barno peer_spad_reg_bar;
 	enum pci_barno db_reg_bar;
+	enum pci_barno mw_bar;
 
 	unsigned int mw_count;
 	unsigned int spad_count;
@@ -92,6 +92,8 @@ struct ntb_epf_data {
 	enum pci_barno peer_spad_reg_bar;
 	/* BAR that contains Doorbell region and Memory window '1' */
 	enum pci_barno db_reg_bar;
+	/* BAR that contains memory windows*/
+	enum pci_barno mw_bar;
 };
 
 static int ntb_epf_send_command(struct ntb_epf_dev *ndev, u32 command,
@@ -411,7 +413,7 @@ static int ntb_epf_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
 		return -EINVAL;
 	}
 
-	bar = idx + NTB_EPF_MW_OFFSET;
+	bar = idx + ndev->mw_bar;
 
 	mw_size = pci_resource_len(ntb->pdev, bar);
 
@@ -453,7 +455,7 @@ static int ntb_epf_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
 	if (idx == 0)
 		offset = readl(ndev->ctrl_reg + NTB_EPF_MW1_OFFSET);
 
-	bar = idx + NTB_EPF_MW_OFFSET;
+	bar = idx + ndev->mw_bar;
 
 	if (base)
 		*base = pci_resource_start(ndev->ntb.pdev, bar) + offset;
@@ -565,6 +567,7 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 			    struct pci_dev *pdev)
 {
 	struct device *dev = ndev->dev;
+	size_t spad_sz, spad_off;
 	int ret;
 
 	pci_set_drvdata(pdev, ndev);
@@ -599,10 +602,16 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 		goto err_dma_mask;
 	}
 
-	ndev->peer_spad_reg = pci_iomap(pdev, ndev->peer_spad_reg_bar, 0);
-	if (!ndev->peer_spad_reg) {
-		ret = -EIO;
-		goto err_dma_mask;
+	if (ndev->peer_spad_reg_bar) {
+		ndev->peer_spad_reg = pci_iomap(pdev, ndev->peer_spad_reg_bar, 0);
+		if (!ndev->peer_spad_reg) {
+			ret = -EIO;
+			goto err_dma_mask;
+		}
+	} else {
+		spad_sz = 4 * readl(ndev->ctrl_reg + NTB_EPF_SPAD_COUNT);
+		spad_off = readl(ndev->ctrl_reg + NTB_EPF_SPAD_OFFSET);
+		ndev->peer_spad_reg = ndev->ctrl_reg + spad_off  + spad_sz;
 	}
 
 	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
@@ -657,6 +666,7 @@ static int ntb_epf_pci_probe(struct pci_dev *pdev,
 	enum pci_barno peer_spad_reg_bar = BAR_1;
 	enum pci_barno ctrl_reg_bar = BAR_0;
 	enum pci_barno db_reg_bar = BAR_2;
+	enum pci_barno mw_bar = BAR_2;
 	struct device *dev = &pdev->dev;
 	struct ntb_epf_data *data;
 	struct ntb_epf_dev *ndev;
@@ -671,17 +681,16 @@ static int ntb_epf_pci_probe(struct pci_dev *pdev,
 
 	data = (struct ntb_epf_data *)id->driver_data;
 	if (data) {
-		if (data->peer_spad_reg_bar)
-			peer_spad_reg_bar = data->peer_spad_reg_bar;
-		if (data->ctrl_reg_bar)
-			ctrl_reg_bar = data->ctrl_reg_bar;
-		if (data->db_reg_bar)
-			db_reg_bar = data->db_reg_bar;
+		peer_spad_reg_bar = data->peer_spad_reg_bar;
+		ctrl_reg_bar = data->ctrl_reg_bar;
+		db_reg_bar = data->db_reg_bar;
+		mw_bar = data->mw_bar;
 	}
 
 	ndev->peer_spad_reg_bar = peer_spad_reg_bar;
 	ndev->ctrl_reg_bar = ctrl_reg_bar;
 	ndev->db_reg_bar = db_reg_bar;
+	ndev->mw_bar = mw_bar;
 	ndev->dev = dev;
 
 	ntb_epf_init_struct(ndev, pdev);
@@ -729,6 +738,14 @@ static const struct ntb_epf_data j721e_data = {
 	.ctrl_reg_bar = BAR_0,
 	.peer_spad_reg_bar = BAR_1,
 	.db_reg_bar = BAR_2,
+	.mw_bar = BAR_2,
+};
+
+static const struct ntb_epf_data mx8_data = {
+	.ctrl_reg_bar = BAR_0,
+	.peer_spad_reg_bar = BAR_0,
+	.db_reg_bar = BAR_2,
+	.mw_bar = BAR_4,
 };
 
 static const struct pci_device_id ntb_epf_pci_tbl[] = {
@@ -737,6 +754,11 @@ static const struct pci_device_id ntb_epf_pci_tbl[] = {
 		.class = PCI_CLASS_MEMORY_RAM << 8, .class_mask = 0xffff00,
 		.driver_data = (kernel_ulong_t)&j721e_data,
 	},
+	{
+		PCI_DEVICE(PCI_VENDOR_ID_FREESCALE, 0x0809),
+		.class = PCI_CLASS_MEMORY_RAM << 8, .class_mask = 0xffff00,
+		.driver_data = (kernel_ulong_t)&mx8_data,
+	},
 	{ },
 };
 
diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
index 733557231ed0..0ed6f809ff2e 100644
--- a/drivers/ntb/hw/idt/ntb_hw_idt.c
+++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
@@ -2406,7 +2406,7 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 				"\t%hhu.\t", idx);
 		else
 			off += scnprintf(strbuf + off, size - off,
-				"\t%hhu-%hhu.\t", idx, idx + cnt - 1);
+				"\t%hhu-%d.\t", idx, idx + cnt - 1);
 
 		off += scnprintf(strbuf + off, size - off, "%s BAR%hhu, ",
 			idt_get_mw_name(data), ndev->mws[idx].bar);
@@ -2435,7 +2435,7 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 					"\t%hhu.\t", idx);
 			else
 				off += scnprintf(strbuf + off, size - off,
-					"\t%hhu-%hhu.\t", idx, idx + cnt - 1);
+					"\t%hhu-%d.\t", idx, idx + cnt - 1);
 
 			off += scnprintf(strbuf + off, size - off,
 				"%s BAR%hhu, ", idt_get_mw_name(data),
@@ -2480,7 +2480,7 @@ static ssize_t idt_dbgfs_info_read(struct file *filp, char __user *ubuf,
 		int src;
 		data = idt_ntb_msg_read(&ndev->ntb, &src, idx);
 		off += scnprintf(strbuf + off, size - off,
-			"\t%hhu. 0x%08x from peer %hhu (Port %hhu)\n",
+			"\t%hhu. 0x%08x from peer %d (Port %hhu)\n",
 			idx, data, src, ndev->peers[src].port);
 	}
 	off += scnprintf(strbuf + off, size - off, "\n");
diff --git a/drivers/ntb/hw/intel/ntb_hw_gen1.c b/drivers/ntb/hw/intel/ntb_hw_gen1.c
index e5f14e20a9ff..72e2027a71c4 100644
--- a/drivers/ntb/hw/intel/ntb_hw_gen1.c
+++ b/drivers/ntb/hw/intel/ntb_hw_gen1.c
@@ -1874,7 +1874,7 @@ static int intel_ntb_pci_probe(struct pci_dev *pdev,
 		rc = gen3_init_dev(ndev);
 		if (rc)
 			goto err_init_dev;
-	} else if (pdev_is_gen4(pdev)) {
+	} else if (pdev_is_gen4(pdev) || pdev_is_gen5(pdev)) {
 		ndev->ntb.ops = &intel_ntb4_ops;
 		rc = intel_ntb_init_pci(ndev, pdev);
 		if (rc)
@@ -2047,6 +2047,8 @@ static const struct pci_device_id intel_ntb_pci_tbl[] = {
 
 	/* GEN4 */
 	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_ICX)},
+	/* SPR has same dev id has ICX but different revision id */
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_GNR)},
 	{0}
 };
 MODULE_DEVICE_TABLE(pci, intel_ntb_pci_tbl);
diff --git a/drivers/ntb/hw/intel/ntb_hw_gen4.c b/drivers/ntb/hw/intel/ntb_hw_gen4.c
index 4081fc538ff4..22cac7975b3c 100644
--- a/drivers/ntb/hw/intel/ntb_hw_gen4.c
+++ b/drivers/ntb/hw/intel/ntb_hw_gen4.c
@@ -197,7 +197,7 @@ int gen4_init_dev(struct intel_ntb_dev *ndev)
 	ppd1 = ioread32(ndev->self_mmio + GEN4_PPD1_OFFSET);
 	if (pdev_is_ICX(pdev))
 		ndev->ntb.topo = gen4_ppd_topo(ndev, ppd1);
-	else if (pdev_is_SPR(pdev))
+	else if (pdev_is_SPR(pdev) || pdev_is_gen5(pdev))
 		ndev->ntb.topo = spr_ppd_topo(ndev, ppd1);
 	dev_dbg(&pdev->dev, "ppd %#x topo %s\n", ppd1,
 		ntb_topo_string(ndev->ntb.topo));
diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.h b/drivers/ntb/hw/intel/ntb_hw_intel.h
index b233d1c6ba2d..380ec0d8e0d9 100644
--- a/drivers/ntb/hw/intel/ntb_hw_intel.h
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.h
@@ -70,6 +70,8 @@
 #define PCI_DEVICE_ID_INTEL_NTB_SS_BDX	0x6F0F
 #define PCI_DEVICE_ID_INTEL_NTB_B2B_SKX	0x201C
 #define PCI_DEVICE_ID_INTEL_NTB_B2B_ICX	0x347e
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_SPR	0x347e
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_GNR	0x0db4
 
 /* Ntb control and link status */
 #define NTB_CTL_CFG_LOCK		BIT(0)
@@ -225,7 +227,14 @@ static inline int pdev_is_gen4(struct pci_dev *pdev)
 {
 	if (pdev->device == PCI_DEVICE_ID_INTEL_NTB_B2B_ICX)
 		return 1;
+	return 0;
+}
 
+static inline int pdev_is_gen5(struct pci_dev *pdev)
+{
+	if (pdev->device == PCI_DEVICE_ID_INTEL_NTB_B2B_GNR)
+		return 1;
 	return 0;
 }
+
 #endif
diff --git a/drivers/ntb/test/ntb_perf.c b/drivers/ntb/test/ntb_perf.c
index 65e1e5cf1b29..af7d3de65eb3 100644
--- a/drivers/ntb/test/ntb_perf.c
+++ b/drivers/ntb/test/ntb_perf.c
@@ -6,6 +6,7 @@
  *
  *   Copyright(c) 2015 Intel Corporation. All rights reserved.
  *   Copyright(c) 2017 T-Platforms. All Rights Reserved.
+ *   Copyright(c) 2022 YADRO. All Rights Reserved.
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of version 2 of the GNU General Public License as
@@ -15,6 +16,7 @@
  *
  *   Copyright(c) 2015 Intel Corporation. All rights reserved.
  *   Copyright(c) 2017 T-Platforms. All Rights Reserved.
+ *   Copyright(c) 2022 YADRO. All Rights Reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
  *   modification, are permitted provided that the following conditions
@@ -65,6 +67,22 @@
  *
  * root@self# echo 0 > $DBG_DIR/run
  * root@self# cat $DBG_DIR/run
+ *-----------------------------------------------------------------------------
+ * Eg: start latency test with peer (index 0) poll-waiting and get the metrics
+ *
+ * Server side:
+ * root@self# echo 0 > $DBG_DIR/poll_latency/run_server
+ * Client side:
+ * root@self# echo 0 > $DBG_DIR/poll_latency/run_client
+ * root@self# cat $DBG_DIR/poll_latency/run_client
+ *-----------------------------------------------------------------------------
+ * Eg: start doorbell latency test with peer (index 0) and get the metrics
+ *
+ * Server side:
+ * root@self# echo 0 > $DBG_DIR/db_latency/run_server
+ * Client side:
+ * root@self# echo 0 > $DBG_DIR/db_latency/run_client
+ * root@self# cat $DBG_DIR/db_latency/run_client
  */
 
 #include <linux/init.h>
@@ -76,6 +94,7 @@
 #include <linux/dmaengine.h>
 #include <linux/pci.h>
 #include <linux/ktime.h>
+#include <linux/jiffies.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/sizes.h>
@@ -85,7 +104,7 @@
 #include <linux/ntb.h>
 
 #define DRIVER_NAME		"ntb_perf"
-#define DRIVER_VERSION		"2.0"
+#define DRIVER_VERSION		"2.3"
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_VERSION(DRIVER_VERSION);
@@ -106,6 +125,9 @@ MODULE_DESCRIPTION("PCIe NTB Performance Measurement Tool");
 
 #define PERF_BUF_LEN 1024
 
+#define LAT_MIN_TRIES	20
+#define RESCHEDULE_RATIO	8192 /* power of 2, to avoid actual division */
+
 static unsigned long max_mw_size;
 module_param(max_mw_size, ulong, 0644);
 MODULE_PARM_DESC(max_mw_size, "Upper limit of memory window size");
@@ -122,6 +144,22 @@ static bool use_dma; /* default to 0 */
 module_param(use_dma, bool, 0644);
 MODULE_PARM_DESC(use_dma, "Use DMA engine to measure performance");
 
+static bool perf_latency = true;
+module_param(perf_latency, bool, 0644);
+MODULE_PARM_DESC(perf_latency, "Measure burst latency");
+
+static unsigned long lat_time_ms = 1000; /* default 1s */
+module_param(lat_time_ms, ulong, 0644);
+MODULE_PARM_DESC(lat_time_ms, "Time (in ms) to test latency");
+
+static unsigned long lat_timeout_us = 500;
+module_param(lat_timeout_us, ulong, 0644);
+MODULE_PARM_DESC(lat_timeout_us, "Timeout (in us) to wait for server reply");
+
+static unsigned long peer_timeout_s = 60;
+module_param(peer_timeout_s, ulong, 0644);
+MODULE_PARM_DESC(peer_timeout_s, "Timeout (in s) to wait for peer link");
+
 /*==============================================================================
  *                         Perf driver data definition
  *==============================================================================
@@ -138,7 +176,21 @@ enum perf_cmd {
 	PERF_STS_LNKUP = 6, /* link up state flag */
 };
 
+enum run_mode {
+	RUN_PL_CLIENT,
+	RUN_PL_SERVER,
+	RUN_DBL_CLIENT,
+	RUN_DBL_SERVER,
+};
+
 struct perf_ctx;
+struct perf_ext_lat_data;
+
+struct perf_ext_lat_ops {
+	int (*init)(struct perf_ext_lat_data *data);
+	int (*run)(struct perf_ext_lat_data *data);
+	void (*clear)(struct perf_ext_lat_data *data);
+};
 
 struct perf_peer {
 	struct perf_ctx	*perf;
@@ -178,12 +230,30 @@ struct perf_thread {
 	void *src;
 	u64 copied;
 	ktime_t duration;
+	ktime_t latency;
+	u64 tries;
 	int status;
 	struct work_struct work;
 };
 #define to_thread_work(__work) \
 	container_of(__work, struct perf_thread, work)
 
+struct perf_ext_lat_data {
+	struct perf_ctx *perf;
+	ktime_t latency;
+	u64 tries;
+	int status;
+	struct perf_ext_lat_ops ops;
+	struct work_struct work;
+
+	union {
+		void *src;
+		int db;
+	};
+};
+#define to_ext_lat_data(__work) \
+	container_of(__work, struct perf_ext_lat_data, work)
+
 struct perf_ctx {
 	struct ntb_dev *ntb;
 
@@ -192,6 +262,12 @@ struct perf_ctx {
 	int pcnt;
 	struct perf_peer *peers;
 
+	/* Ext latency tests interface */
+	enum run_mode mode;
+	struct perf_ext_lat_data pldata;
+	struct perf_ext_lat_data dbldata;
+	atomic_t running;
+
 	/* Performance measuring work-threads interface */
 	unsigned long busy_flag;
 	wait_queue_head_t twait;
@@ -239,6 +315,8 @@ static struct dentry *perf_dbgfs_topdir;
 
 static struct workqueue_struct *perf_wq __read_mostly;
 
+static const u8 stop_word = 0xFF;
+
 /*==============================================================================
  *                  NTB cross-link commands execution service
  *==============================================================================
@@ -501,6 +579,15 @@ static void perf_link_event(void *ctx)
 	}
 }
 
+static inline void perf_dbl_pong(struct perf_ctx *perf)
+{
+	struct perf_ext_lat_data *data = &perf->dbldata;
+
+	ntb_db_clear(perf->ntb, BIT_ULL(data->db));
+	data->tries++;
+	ntb_peer_db_set(perf->ntb, BIT_ULL(data->db));
+}
+
 static void perf_db_event(void *ctx, int vec)
 {
 	struct perf_ctx *perf = ctx;
@@ -509,7 +596,11 @@ static void perf_db_event(void *ctx, int vec)
 		ntb_db_vector_mask(perf->ntb, vec), ntb_db_read(perf->ntb));
 
 	/* Just receive all available commands */
-	(void)perf_cmd_recv(perf);
+	if (perf->dbldata.db >= 0 &&
+				BIT_ULL(perf->dbldata.db) & ntb_db_read(perf->ntb))
+		perf_dbl_pong(perf);
+	else
+		(void)perf_cmd_recv(perf);
 }
 
 static void perf_msg_event(void *ctx)
@@ -664,6 +755,8 @@ static int perf_init_service(struct perf_ctx *perf)
 		return -EINVAL;
 	}
 
+	perf->dbldata.db = -1;
+
 	if (ntb_msg_count(perf->ntb) >= PERF_MSG_CNT) {
 		perf->cmd_send = perf_msg_cmd_send;
 		perf->cmd_recv = perf_msg_cmd_recv;
@@ -783,7 +876,7 @@ static void perf_dma_copy_callback(void *data)
 }
 
 static int perf_copy_chunk(struct perf_thread *pthr,
-			   void __iomem *dst, void *src, size_t len)
+			   void __iomem *dst, void *src, size_t len, bool _use_dma)
 {
 	struct dma_async_tx_descriptor *tx;
 	struct dmaengine_unmap_data *unmap;
@@ -794,7 +887,7 @@ static int perf_copy_chunk(struct perf_thread *pthr,
 	void __iomem *dst_vaddr;
 	dma_addr_t dst_dma_addr;
 
-	if (!use_dma) {
+	if (!_use_dma) {
 		memcpy_toio(dst, src, len);
 		goto ret_check_tsync;
 	}
@@ -940,7 +1033,7 @@ static int perf_run_test(struct perf_thread *pthr)
 
 	/* Copied field is cleared on test launch stage */
 	while (pthr->copied < total_size) {
-		ret = perf_copy_chunk(pthr, flt_dst, flt_src, chunk_size);
+		ret = perf_copy_chunk(pthr, flt_dst, flt_src, chunk_size, use_dma);
 		if (ret) {
 			dev_err(&perf->ntb->dev, "%d: Got error %d on test\n",
 				pthr->tidx, ret);
@@ -1018,6 +1111,69 @@ no_dma_notify:
 	kfree(pthr->src);
 }
 
+static int perf_run_latency(struct perf_thread *pthr)
+{
+	struct perf_peer *peer = pthr->perf->test_peer;
+	struct ntb_dev *ntb = pthr->perf->ntb;
+	void __iomem *flt_dst, *bnd_dst;
+	void *flt_src;
+	u64 stop_at;
+	u32 rem;
+	int ret;
+
+	pthr->tries = 0;
+	pthr->latency = ktime_get();
+	flt_src = pthr->src;
+	flt_dst = peer->outbuf;
+	bnd_dst = peer->outbuf + peer->outbuf_size;
+
+	stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+	while (ktime_get_real_fast_ns() < stop_at) {
+		ret = perf_copy_chunk(pthr, flt_dst, flt_src, 1, false);
+		if (ret) {
+			dev_err(&ntb->dev, "%d: Latency testing error %d\n",
+				pthr->tidx, ret);
+			pthr->latency = ktime_set(0, 0);
+			return ret;
+		}
+
+		pthr->tries++;
+		flt_dst++;
+		flt_src++;
+
+		if (flt_dst >= bnd_dst || flt_dst < peer->outbuf) {
+			flt_dst = peer->outbuf;
+			flt_src = pthr->src;
+		}
+
+		/* Avoid processor soft lock-ups */
+		div_u64_rem(pthr->tries, RESCHEDULE_RATIO, &rem);
+		if (!rem)
+			schedule();
+	}
+
+	/* Stop timer */
+	pthr->latency = ktime_sub(ktime_get(), pthr->latency);
+
+	if (pthr->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev,
+			"%d: Too few steps (%llu) to measure Latency, recommended > %d. Increase value of 'lat_time_ms' parameter\n",
+			pthr->tidx, pthr->tries, LAT_MIN_TRIES);
+		pthr->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "%d: made %llu tries, lasted %llu usecs\n",
+		pthr->tidx, pthr->tries, ktime_to_us(pthr->latency));
+
+	pthr->latency = ns_to_ktime(ktime_divns(pthr->latency, pthr->tries));
+
+	dev_dbg(&ntb->dev, "%d: latency %llu us (%llu ns)\n", pthr->tidx,
+		ktime_to_us(pthr->latency), ktime_to_ns(pthr->latency));
+
+	return 0;
+}
+
 static void perf_thread_work(struct work_struct *work)
 {
 	struct perf_thread *pthr = to_thread_work(work);
@@ -1043,11 +1199,284 @@ static void perf_thread_work(struct work_struct *work)
 	}
 
 	pthr->status = perf_sync_test(pthr);
+	if (pthr->status)
+		goto err_clear_test;
+
+	if (perf_latency)
+		pthr->status = perf_run_latency(pthr);
 
 err_clear_test:
 	perf_clear_test(pthr);
 }
 
+static int perf_init_pl(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	u8 *bp;
+
+	pldata->src = kmalloc_node(peer->outbuf_size, GFP_KERNEL,
+				dev_to_node(&perf->ntb->dev));
+	if (!pldata->src)
+		return -ENOMEM;
+
+	/*
+	 * Prepare random data to send, guaranteed exclusion of 0x00 (unreceived)
+	 * and 0xFF (stop_word)
+	 */
+	get_random_bytes(pldata->src, peer->outbuf_size);
+	for (bp = pldata->src; bp < (u8 *) pldata->src + peer->outbuf_size; bp++)
+		while (*bp == 0 || *bp == stop_word)
+			*bp = (u8)get_random_int();
+
+	memset(peer->inbuf, 0, peer->inbuf_size);
+
+	return 0;
+}
+
+static int perf_poll_peer_reply(volatile u8 *cur)
+{
+	u64 wait_till = ktime_get_real_fast_ns() + lat_timeout_us * NSEC_PER_USEC;
+
+	while (ktime_get_real_fast_ns() < wait_till) {
+		if (*cur == stop_word) {
+			*cur = 0;
+			return 1;
+		}
+		if (*cur != 0) {
+			*cur = 0;
+			return 0;
+		}
+	}
+	return -EINTR;
+}
+
+static int perf_run_pl_client(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	struct ntb_dev *ntb = perf->ntb;
+	void *src = pldata->src;
+	u64 stop_at;
+	int ret;
+
+	dev_dbg(&ntb->dev, "poll_lat: client started.\n");
+
+	pldata->tries = 0;
+	pldata->latency = ktime_get();
+
+	stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+	while (ktime_get_real_fast_ns() < stop_at) {
+		memcpy_toio(peer->outbuf, src, 1);
+
+		/* Avoid processor soft lock-ups */
+		schedule();
+
+		ret = perf_poll_peer_reply(peer->inbuf);
+		if (ret < 0) {
+			dev_err(&ntb->dev, "Timeout waiting for peer reply on poll latency\n");
+			pldata->latency = ktime_set(0, 0);
+			return -EINTR;
+		} else if (ret == 1) {
+			dev_warn(&ntb->dev, "Server terminated on poll latency, stopping\n");
+			break;
+		} else if (!atomic_read(&perf->running)) {
+			dev_err(&ntb->dev, "Poll latency client terminated\n");
+			return -EINTR;
+		}
+
+		pldata->tries++;
+		src++;
+
+		if (src >= pldata->src + peer->outbuf_size)
+			src = pldata->src;
+	}
+
+	/* Stop timer */
+	pldata->latency = ktime_sub(ktime_get(), pldata->latency);
+	/* Send stop to peer */
+	memcpy_toio(peer->outbuf, &stop_word, 1);
+
+	if (pldata->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev,
+			"Too few steps (%llu) to measure Latency, recommended > %d. Increase value of 'lat_time_ms' parameter\n",
+			pldata->tries, LAT_MIN_TRIES);
+		pldata->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "poll_lat: made %llu tries, lasted %llu usecs\n",
+		pldata->tries, ktime_to_us(pldata->latency));
+
+	pldata->latency = ns_to_ktime(ktime_divns(pldata->latency, pldata->tries));
+
+	dev_dbg(&ntb->dev, "poll_lat: latency %llu us (%llu ns)\n",
+		ktime_to_us(pldata->latency), ktime_to_ns(pldata->latency));
+
+	return 0;
+}
+
+static int perf_run_pl_server(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+	struct ntb_dev *ntb = perf->ntb;
+	void *src = pldata->src;
+	int ret = 0;
+
+	dev_dbg(&ntb->dev, "poll_lat: server started.\n");
+
+	pldata->tries = 0;
+
+	while (ret != 1 && atomic_read(&perf->running)) {
+		ret = perf_poll_peer_reply(peer->inbuf);
+		if (!ret) {
+			/* Pong to client */
+			memcpy_toio(peer->outbuf, src++, 1);
+			if (src >= pldata->src + peer->outbuf_size)
+				src = pldata->src;
+
+			pldata->tries++;
+		}
+
+		/* Avoid processor soft lock-ups */
+		schedule();
+	}
+
+	if (pldata->tries < LAT_MIN_TRIES)
+		dev_warn(&ntb->dev,
+			"Poll latency test terminated too early. Increase client's test time\n");
+
+	dev_dbg(&ntb->dev, "poll_lat: server stopped, had responded %llu times\n",
+		pldata->tries);
+
+	return atomic_read(&perf->running) ? -ENODATA : -EINTR;
+}
+
+static void perf_clear_pl(struct perf_ext_lat_data *pldata)
+{
+	struct perf_ctx *perf = pldata->perf;
+	struct perf_peer *peer = perf->test_peer;
+
+	memset(peer->inbuf, stop_word, 1);
+	atomic_set(&perf->running, 0);
+	wake_up(&perf->twait);
+	kfree(pldata->src);
+}
+
+static struct perf_ext_lat_ops perf_pl_client_ops = {
+	.init = perf_init_pl,
+	.run = perf_run_pl_client,
+	.clear = perf_clear_pl
+};
+
+static struct perf_ext_lat_ops perf_pl_server_ops = {
+	.init = perf_init_pl,
+	.run = perf_run_pl_server,
+	.clear = perf_clear_pl
+};
+
+static int perf_init_dbl(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+
+	data->db = get_bitmask_order(ntb_db_valid_mask(perf->ntb)) - 1;
+	dev_dbg(&perf->ntb->dev, "DB bit for latency test: %d\n", data->db);
+
+	if (data->db <= perf->gidx) {
+		dev_err(&perf->ntb->dev, "No spare DoorBell found\n");
+		data->db = -1;
+		return -ENOSPC;
+	}
+
+	return ntb_db_clear_mask(perf->ntb, BIT_ULL(data->db));
+}
+
+static int perf_run_dbl_client(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+	struct ntb_dev *ntb = perf->ntb;
+	u64 stop_at;
+
+	dev_dbg(&ntb->dev, "db_lat: client started.\n");
+
+	data->tries = 0;
+	data->latency = ktime_get();
+
+	if (ntb_peer_db_set(perf->ntb, BIT_ULL(data->db)))
+		return -EIO;
+
+	stop_at = ktime_get_real_fast_ns() + lat_time_ms * NSEC_PER_MSEC;
+	while (ktime_get_real_fast_ns() < stop_at) {
+		/* Avoid processor soft lock-ups */
+		schedule();
+
+		if (!atomic_read(&perf->running)) {
+			dev_err(&ntb->dev, "DoorBell latency client terminated\n");
+			return -EINTR;
+		}
+	}
+
+	/* Stop timer */
+	data->latency = ktime_sub(ktime_get(), data->latency);
+
+	if (data->tries < LAT_MIN_TRIES) {
+		dev_err(&ntb->dev,
+			"Too few steps (%llu) to measure Latency, recommended > %d. Increase value of 'lat_time_ms' parameter\n",
+			data->tries, LAT_MIN_TRIES);
+		data->latency = ktime_set(0, 0);
+		return -EINVAL;
+	}
+
+	dev_dbg(&ntb->dev, "db_lat: made %llu tries, lasted %llu usecs\n",
+		data->tries, ktime_to_us(data->latency));
+
+	data->latency = ns_to_ktime(ktime_divns(data->latency, data->tries));
+
+	dev_dbg(&ntb->dev, "db_lat: latency %llu us (%llu ns)\n",
+		ktime_to_us(data->latency), ktime_to_ns(data->latency));
+
+	return 0;
+}
+
+static void perf_clear_dbl(struct perf_ext_lat_data *data)
+{
+	struct perf_ctx *perf = data->perf;
+
+	data->db = -1;
+	ntb_db_set_mask(perf->ntb, BIT_ULL(data->db));
+	atomic_set(&perf->running, 0);
+	wake_up(&perf->twait);
+}
+
+static struct perf_ext_lat_ops perf_dbl_client_ops = {
+	.init = perf_init_dbl,
+	.run = perf_run_dbl_client,
+	.clear = perf_clear_dbl
+};
+
+static void perf_ext_lat_work(struct work_struct *work)
+{
+	struct perf_ext_lat_data *data = to_ext_lat_data(work);
+
+	if (!data->ops.init || !data->ops.run || !data->ops.clear) {
+		struct perf_ctx *perf = data->perf;
+
+		data->status = -EFAULT;
+		atomic_set(&perf->running, 0);
+		wake_up(&perf->twait);
+		return;
+	}
+
+	data->status = data->ops.init(data);
+	if (data->status)
+		return;
+
+	data->status = data->ops.run(data);
+
+	data->ops.clear(data);
+}
+
 static int perf_set_tcnt(struct perf_ctx *perf, u8 tcnt)
 {
 	if (tcnt == 0 || tcnt > MAX_THREADS_CNT)
@@ -1068,7 +1497,10 @@ static void perf_terminate_test(struct perf_ctx *perf)
 	int tidx;
 
 	atomic_set(&perf->tsync, -1);
+	atomic_set(&perf->running, 0);
 	wake_up(&perf->twait);
+	cancel_work_sync(&perf->pldata.work);
+	cancel_work_sync(&perf->dbldata.work);
 
 	for (tidx = 0; tidx < MAX_THREADS_CNT; tidx++) {
 		wake_up(&perf->threads[tidx].dma_wait);
@@ -1082,9 +1514,10 @@ static int perf_submit_test(struct perf_peer *peer)
 	struct perf_thread *pthr;
 	int tidx, ret;
 
-	ret = wait_for_completion_interruptible(&peer->init_comp);
-	if (ret < 0)
-		return ret;
+	ret = wait_for_completion_interruptible_timeout(&peer->init_comp,
+			msecs_to_jiffies(peer_timeout_s * 1000));
+	if (ret <= 0)
+		return ret ? ret : -ETIMEDOUT;
 
 	if (test_and_set_bit_lock(0, &perf->busy_flag))
 		return -EBUSY;
@@ -1114,6 +1547,63 @@ static int perf_submit_test(struct perf_peer *peer)
 	return ret;
 }
 
+static int perf_submit_ext_lat(struct perf_peer *peer)
+{
+	struct perf_ctx *perf = peer->perf;
+	int ret;
+
+	ret = wait_for_completion_interruptible_timeout(&peer->init_comp,
+			msecs_to_jiffies(peer_timeout_s * 1000));
+	if (ret <= 0)
+		return ret ? ret : -ETIMEDOUT;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	perf->test_peer = peer;
+	atomic_set(&perf->running, 1);
+	perf->pldata.status = -ENODATA;
+	perf->pldata.tries = 0;
+	perf->pldata.latency = ktime_set(0, 0);
+	perf->dbldata.status = -ENODATA;
+	perf->dbldata.tries = 0;
+	perf->dbldata.latency = ktime_set(0, 0);
+
+	switch (perf->mode) {
+	case RUN_PL_SERVER:
+		perf->pldata.ops = perf_pl_server_ops;
+		(void)queue_work(perf_wq, &perf->pldata.work);
+		break;
+	case RUN_PL_CLIENT:
+		perf->pldata.ops = perf_pl_client_ops;
+		(void)queue_work(perf_wq, &perf->pldata.work);
+		break;
+	case RUN_DBL_SERVER:
+		ret = perf_init_dbl(&perf->dbldata);
+		dev_dbg(&perf->ntb->dev, "db_lat: server started.\n");
+		goto submit_exit;
+	case RUN_DBL_CLIENT:
+		perf->dbldata.ops = perf_dbl_client_ops;
+		(void)queue_work(perf_wq, &perf->dbldata.work);
+		break;
+	default:
+		ret = -EINVAL;
+		goto submit_exit;
+	}
+
+	ret = wait_event_interruptible(perf->twait,
+				       !atomic_read(&perf->running));
+	if (ret == -ERESTARTSYS) {
+		perf_terminate_test(perf);
+		ret = -EINTR;
+	}
+
+submit_exit:
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
 static int perf_read_stats(struct perf_ctx *perf, char *buf,
 			   size_t size, ssize_t *pos)
 {
@@ -1142,6 +1632,18 @@ static int perf_read_stats(struct perf_ctx *perf, char *buf,
 			"%d: copied %llu bytes in %llu usecs, %llu MBytes/s\n",
 			tidx, pthr->copied, ktime_to_us(pthr->duration),
 			div64_u64(pthr->copied, ktime_to_us(pthr->duration)));
+
+		if (perf_latency && ktime_compare(pthr->latency, ktime_set(0, 0))) {
+			if (ktime_to_us(pthr->latency) < 10) {
+				(*pos) += scnprintf(buf + *pos, size - *pos,
+						"%d: latency %llu ns\n",
+						tidx, ktime_to_ns(pthr->latency));
+			} else {
+				(*pos) += scnprintf(buf + *pos, size - *pos,
+						"%d: latency %llu us\n",
+						tidx, ktime_to_us(pthr->latency));
+			}
+		}
 	}
 
 	clear_bit_unlock(0, &perf->busy_flag);
@@ -1149,7 +1651,7 @@ static int perf_read_stats(struct perf_ctx *perf, char *buf,
 	return 0;
 }
 
-static void perf_init_threads(struct perf_ctx *perf)
+static void perf_init_workers(struct perf_ctx *perf)
 {
 	struct perf_thread *pthr;
 	int tidx;
@@ -1158,6 +1660,14 @@ static void perf_init_threads(struct perf_ctx *perf)
 	perf->test_peer = &perf->peers[0];
 	init_waitqueue_head(&perf->twait);
 
+	perf->pldata.perf = perf;
+	INIT_WORK(&perf->pldata.work, perf_ext_lat_work);
+	perf->pldata.status = -ENODATA;
+
+	perf->dbldata.perf = perf;
+	INIT_WORK(&perf->dbldata.work, perf_ext_lat_work);
+	perf->dbldata.status = -ENODATA;
+
 	for (tidx = 0; tidx < MAX_THREADS_CNT; tidx++) {
 		pthr = &perf->threads[tidx];
 
@@ -1169,7 +1679,7 @@ static void perf_init_threads(struct perf_ctx *perf)
 	}
 }
 
-static void perf_clear_threads(struct perf_ctx *perf)
+static void perf_clear_workers(struct perf_ctx *perf)
 {
 	perf_terminate_test(perf);
 }
@@ -1313,6 +1823,193 @@ static const struct file_operations perf_dbgfs_run = {
 	.write = perf_dbgfs_write_run
 };
 
+static ssize_t perf_dbgfs_read_run_pl(struct file *filep, char __user *ubuf,
+				   size_t fsize, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	ssize_t size = PERF_BUF_LEN;
+	ssize_t pos = 0;
+	ssize_t ret;
+	char *buf;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos += scnprintf(buf + pos, size - pos,
+		"    Peer %d test statistics:\n", perf->test_peer->pidx);
+
+	if (perf->pldata.status != -ENODATA) {
+		if (perf->pldata.status) {
+			pos += scnprintf(buf + pos, size - pos,
+				"poll latency: error status %d\n", perf->pldata.status);
+		} else {
+			if (ktime_to_us(perf->pldata.latency) < 10) {
+				pos += scnprintf(buf + pos, size - pos,
+						"poll latency %llu ns\n",
+						ktime_to_ns(perf->pldata.latency));
+			} else {
+				pos += scnprintf(buf + pos, size - pos,
+						"poll latency %llu us\n",
+						ktime_to_us(perf->pldata.latency));
+			}
+		}
+	} else {
+		pos += scnprintf(buf + pos, size - pos, "Test did not run\n");
+	}
+
+	ret = simple_read_from_buffer(ubuf, fsize, offp, buf, pos);
+
+	kfree(buf);
+
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_write_run_ext(struct file *filep, const char __user *ubuf,
+					size_t size, loff_t *offp, enum run_mode mode)
+{
+	struct perf_ctx *perf = filep->private_data;
+	struct ntb_dev *ntb = perf->ntb;
+	struct perf_peer *peer;
+	int pidx, ret;
+
+	ret = kstrtoint_from_user(ubuf, size, 0, &pidx);
+	if (ret)
+		return ret;
+
+	if (pidx < 0) {
+		switch (mode) {
+		case RUN_PL_SERVER:
+			dev_dbg(&ntb->dev, "poll_lat: kill server\n");
+			if (test_bit(0, &perf->busy_flag)) {
+				peer = perf->test_peer;
+				/* Send stop to client */
+				memcpy_toio(peer->outbuf, &stop_word, 1);
+			}
+			perf_terminate_test(perf);
+			clear_bit_unlock(0, &perf->busy_flag);
+			return size;
+		case RUN_DBL_SERVER:
+			dev_dbg(&ntb->dev, "db_lat: kill server\n");
+			perf_clear_dbl(&perf->dbldata);
+			clear_bit_unlock(0, &perf->busy_flag);
+			return size;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (pidx >= perf->pcnt)
+		return -EINVAL;
+
+	peer = &perf->peers[pidx];
+	perf->mode = mode;
+
+	ret = perf_submit_ext_lat(peer);
+
+	return ret ? ret : size;
+}
+
+static ssize_t perf_dbgfs_write_run_pl_client(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_PL_CLIENT);
+}
+
+static const struct file_operations perf_dbgfs_run_pl_client = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_pl,
+	.write = perf_dbgfs_write_run_pl_client
+};
+
+static ssize_t perf_dbgfs_write_run_pl_server(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_PL_SERVER);
+}
+
+static const struct file_operations perf_dbgfs_run_pl_server = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_pl,
+	.write = perf_dbgfs_write_run_pl_server
+};
+
+static ssize_t perf_dbgfs_read_run_dbl(struct file *filep, char __user *ubuf,
+				   size_t fsize, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	ssize_t size = PERF_BUF_LEN;
+	ssize_t pos = 0;
+	ssize_t ret;
+	char *buf;
+
+	if (test_and_set_bit_lock(0, &perf->busy_flag))
+		return -EBUSY;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos += scnprintf(buf + pos, size - pos,
+		"    Peer %d test statistics:\n", perf->test_peer->pidx);
+
+	if (perf->dbldata.status != -ENODATA) {
+		if (perf->dbldata.status) {
+			pos += scnprintf(buf + pos, size - pos,
+				"doorbell latency: error status %d\n", perf->dbldata.status);
+		} else {
+			if (ktime_to_us(perf->dbldata.latency) < 10) {
+				pos += scnprintf(buf + pos, size - pos,
+						"doorbell latency %llu ns\n",
+						ktime_to_ns(perf->dbldata.latency));
+			} else {
+				pos += scnprintf(buf + pos, size - pos,
+						"doorbell latency %llu us\n",
+						ktime_to_us(perf->dbldata.latency));
+			}
+		}
+	} else {
+		pos += scnprintf(buf + pos, size - pos, "Test did not run\n");
+	}
+
+	ret = simple_read_from_buffer(ubuf, fsize, offp, buf, pos);
+
+	kfree(buf);
+
+	clear_bit_unlock(0, &perf->busy_flag);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_write_run_dbl_client(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_DBL_CLIENT);
+}
+
+static const struct file_operations perf_dbgfs_run_dbl_client = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_dbl,
+	.write = perf_dbgfs_write_run_dbl_client
+};
+
+static ssize_t perf_dbgfs_write_run_dbl_server(struct file *filep,
+					const char __user *ubuf, size_t size, loff_t *offp)
+{
+	return perf_dbgfs_write_run_ext(filep, ubuf, size, offp, RUN_DBL_SERVER);
+}
+
+static const struct file_operations perf_dbgfs_run_dbl_server = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_run_dbl,
+	.write = perf_dbgfs_write_run_dbl_server
+};
+
 static ssize_t perf_dbgfs_read_tcnt(struct file *filep, char __user *ubuf,
 				    size_t size, loff_t *offp)
 {
@@ -1344,15 +2041,76 @@ static ssize_t perf_dbgfs_write_tcnt(struct file *filep,
 	return size;
 }
 
+static ssize_t perf_dbgfs_read_lattrs(struct file *filep, char __user *ubuf,
+				    size_t size, loff_t *offp)
+{
+	size_t buf_size = min_t(size_t, size, PERF_BUF_LEN);
+	struct perf_ctx *perf = filep->private_data;
+	ssize_t pos, ret;
+	char *buf;
+	int tidx;
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos = scnprintf(buf, buf_size, "    Peer %d latency try count:\n",
+			perf->test_peer->pidx);
+
+	for (tidx = 0; tidx < perf->tcnt; tidx++) {
+		struct perf_thread *pthr = &perf->threads[tidx];
+
+		pos += scnprintf(buf + pos, buf_size - pos,
+				"%d: made %llu tries\n", tidx, pthr->tries);
+	}
+
+	ret = simple_read_from_buffer(ubuf, size, offp, buf, pos);
+
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t perf_dbgfs_read_inbuf(struct file *filep, char __user *ubuf,
+					size_t size, loff_t *offp)
+{
+	struct perf_ctx *perf = filep->private_data;
+	char buf[32];
+	ssize_t pos;
+	u64 *value;
+
+	if (!perf->test_peer || !perf->test_peer->inbuf) {
+		pos = scnprintf(buf, sizeof(buf), "NULL\n");
+	} else {
+		value = perf->test_peer->inbuf;
+		pos = scnprintf(buf, sizeof(buf), "0x%llx\n", *value);
+	}
+
+	return simple_read_from_buffer(ubuf, size, offp, buf, pos);
+}
+
 static const struct file_operations perf_dbgfs_tcnt = {
 	.open = simple_open,
 	.read = perf_dbgfs_read_tcnt,
 	.write = perf_dbgfs_write_tcnt
 };
 
+static const struct file_operations perf_dbgfs_lattrs = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_lattrs
+};
+
+static const struct file_operations perf_dbgfs_inbuf = {
+	.open = simple_open,
+	.read = perf_dbgfs_read_inbuf,
+};
+
 static void perf_setup_dbgfs(struct perf_ctx *perf)
 {
 	struct pci_dev *pdev = perf->ntb->pdev;
+	struct dentry *burst_lat_dir;
+	struct dentry *poll_lat_dir;
+	struct dentry *db_lat_dir;
 
 	perf->dbgfs_dir = debugfs_create_dir(pci_name(pdev), perf_dbgfs_topdir);
 	if (!perf->dbgfs_dir) {
@@ -1363,11 +2121,10 @@ static void perf_setup_dbgfs(struct perf_ctx *perf)
 	debugfs_create_file("info", 0600, perf->dbgfs_dir, perf,
 			    &perf_dbgfs_info);
 
-	debugfs_create_file("run", 0600, perf->dbgfs_dir, perf,
-			    &perf_dbgfs_run);
+	debugfs_create_symlink("run", perf->dbgfs_dir, "burst_latency/run");
 
-	debugfs_create_file("threads_count", 0600, perf->dbgfs_dir, perf,
-			    &perf_dbgfs_tcnt);
+	debugfs_create_symlink("threads_count", perf->dbgfs_dir,
+				"burst_latency/threads_count");
 
 	/* They are made read-only for test exec safety and integrity */
 	debugfs_create_u8("chunk_order", 0500, perf->dbgfs_dir, &chunk_order);
@@ -1375,6 +2132,45 @@ static void perf_setup_dbgfs(struct perf_ctx *perf)
 	debugfs_create_u8("total_order", 0500, perf->dbgfs_dir, &total_order);
 
 	debugfs_create_bool("use_dma", 0500, perf->dbgfs_dir, &use_dma);
+
+	debugfs_create_file("inbuf", 0400, perf->dbgfs_dir, perf,
+			    &perf_dbgfs_inbuf);
+
+	/* burst_latency subdir */
+
+	burst_lat_dir = debugfs_create_dir("burst_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run", 0600, burst_lat_dir, perf, &perf_dbgfs_run);
+
+	debugfs_create_file("threads_count", 0600, burst_lat_dir, perf,
+			    &perf_dbgfs_tcnt);
+
+	debugfs_create_file("tries", 0400, burst_lat_dir, perf,
+			    &perf_dbgfs_lattrs);
+
+	/* poll_latency subdir */
+
+	poll_lat_dir = debugfs_create_dir("poll_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run_client", 0600, poll_lat_dir, perf,
+			    &perf_dbgfs_run_pl_client);
+
+	debugfs_create_file("run_server", 0600, poll_lat_dir, perf,
+			    &perf_dbgfs_run_pl_server);
+
+	debugfs_create_u64("tries", 0400, poll_lat_dir, &perf->pldata.tries);
+
+	/* db_latency subdir */
+
+	db_lat_dir = debugfs_create_dir("db_latency", perf->dbgfs_dir);
+
+	debugfs_create_file("run_client", 0600, db_lat_dir, perf,
+			    &perf_dbgfs_run_dbl_client);
+
+	debugfs_create_file("run_server", 0600, db_lat_dir, perf,
+			    &perf_dbgfs_run_dbl_server);
+
+	debugfs_create_u64("tries", 0400, db_lat_dir, &perf->dbldata.tries);
 }
 
 static void perf_clear_dbgfs(struct perf_ctx *perf)
@@ -1494,7 +2290,7 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
 	if (ret)
 		return ret;
 
-	perf_init_threads(perf);
+	perf_init_workers(perf);
 
 	ret = perf_init_service(perf);
 	if (ret)
@@ -1517,7 +2313,7 @@ static void perf_remove(struct ntb_client *client, struct ntb_dev *ntb)
 
 	perf_disable_service(perf);
 
-	perf_clear_threads(perf);
+	perf_clear_workers(perf);
 }
 
 static struct ntb_client perf_client = {
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index cf1627679716..83ddb190292e 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -161,7 +161,11 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
 	u32 free_win;
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows);
+	if (!ep->bar_to_atu[bar])
+		free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows);
+	else
+		free_win = ep->bar_to_atu[bar];
+
 	if (free_win >= pci->num_ib_windows) {
 		dev_err(pci->dev, "No free inbound window\n");
 		return -EINVAL;
@@ -218,6 +222,7 @@ static void dw_pcie_ep_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_IB, atu_index);
 	clear_bit(atu_index, ep->ib_window_map);
 	ep->epf_bar[bar] = NULL;
+	ep->bar_to_atu[bar] = 0;
 }
 
 static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
@@ -245,6 +250,9 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	if (ret)
 		return ret;
 
+	if (ep->epf_bar[bar])
+		return 0;
+
 	dw_pcie_dbi_ro_wr_en(pci);
 
 	dw_pcie_writel_dbi2(pci, reg, lower_32_bits(size - 1));
diff --git a/drivers/pci/endpoint/functions/Kconfig b/drivers/pci/endpoint/functions/Kconfig
index 5f1242ca2f4e..362555b024e8 100644
--- a/drivers/pci/endpoint/functions/Kconfig
+++ b/drivers/pci/endpoint/functions/Kconfig
@@ -25,3 +25,14 @@ config PCI_EPF_NTB
 	  device tree.
 
 	  If in doubt, say "N" to disable Endpoint NTB driver.
+
+config PCI_EPF_VNTB
+        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
+          between PCI host and PCIe Endpoint.
+
+          If in doubt, say "N" to disable Endpoint NTB driver.
diff --git a/drivers/pci/endpoint/functions/Makefile b/drivers/pci/endpoint/functions/Makefile
index 96ab932a537a..5c13001deaba 100644
--- a/drivers/pci/endpoint/functions/Makefile
+++ b/drivers/pci/endpoint/functions/Makefile
@@ -5,3 +5,4 @@
 
 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
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 000000000000..111568089d45
--- /dev/null
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -0,0 +1,1425 @@
+// 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      |
+ * +------------+         +---------------+--------+--------------+
+ *     PCI RC                        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
+
+#define VNTB_VID			0x1957
+#define VNTB_PID			0x080A
+
+enum epf_ntb_bar {
+	BAR_CONFIG,
+	BAR_DB,
+	BAR_MW0,
+	BAR_MW1,
+	BAR_MW2,
+};
+
+/*
+ * +--------------------------------------------------+ Base
+ * |                                                  |
+ * |                                                  |
+ * |                                                  |
+ * |          Common Control Register                 |
+ * |                                                  |
+ * |                                                  |
+ * |                                                  |
+ * +-----------------------+--------------------------+ Base+span_offset
+ * |                       |                          |
+ * |    Peer Span Space    |    Span Space            |
+ * |                       |                          |
+ * |                       |                          |
+ * +-----------------------+--------------------------+ Base+span_offset
+ * |                       |                          |     +span_count * 4
+ * |                       |                          |
+ * |     Span Space        |   Peer Span 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;
+
+	bool linkup;
+	u32 spad_size;
+
+	enum pci_barno epf_ntb_bar[6];
+
+	struct epf_ntb_ctrl *reg;
+
+	phys_addr_t epf_db_phy;
+	void __iomem *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
+ * @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.
+ */
+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
+ */
+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,
+			"intf: 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 (readl(ntb->epf_db + i * 4)) {
+			if (readl(ntb->epf_db + i * 4))
+				ntb->db |= 1 << (i - 1);
+
+			ntb_db_event(&ntb->ntb, i);
+			writel(0, ntb->epf_db + i * 4);
+		}
+	}
+
+	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, "intf 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: 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 HOST2's peer
+ * scratchpad is HOST1's self scratchpad.
+ */
+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 1 which contains the HOST1'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.
+ */
+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 HOST1 and HOST2
+ *
+ * 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.
+ */
+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 * 4;
+
+	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, "intf: 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 = 4;
+
+	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 capaiblity
+ * @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.
+ */
+static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	bool msix_capable, msi_capable;
+	u8 func_no, vfunc_no;
+	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);
+	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->epf->func_no;
+	vfunc_no = ntb->epf->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;
+
+	if (msi_capable) {
+		ret = pci_epc_set_msi(ntb->epf->epc, func_no, vfunc_no, 16);
+		if (ret) {
+			dev_err(dev, "intf: 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
+ *
+ */
+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 = 4 * 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, "intf: 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, "intf: DoorBell BAR set failed\n");
+			goto err_alloc_peer_mem;
+	}
+	return ret;
+
+err_alloc_peer_mem:
+	pci_epc_mem_free_addr(ntb->epf->epc, epf_bar->phys_addr, mw_addr, epf_bar->size);
+	return -1;
+}
+
+/**
+ * epf_ntb_db_bar_clear() - Clear doorbell BAR and free memory
+ *   allocated in peers 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
+ *
+ */
+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 = 0;
+		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, "intf: 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]) {
+			dev_err(dev, "Failed to allocate source address\n");
+			goto err_alloc_mem;
+		}
+	}
+
+	return ret;
+err_alloc_mem:
+	return ret;
+}
+
+/**
+ * epf_ntb_mw_bar_clear() - Clear Memory window BARs
+ * @ntb: NTB device that facilitates communication between HOST and vHOST
+ *
+ */
+static void epf_ntb_mw_bar_clear(struct epf_ntb *ntb)
+{
+	enum pci_barno barno;
+	int i;
+
+	for (i = 0; i < ntb->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
+ *
+ */
+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, "intf: 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 vHOST2
+ *
+ * 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(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, "intf: Config/self SPAD BAR init failed");
+		return ret;
+	}
+
+	ret = epf_ntb_configure_interrupt(ntb);
+	if (ret) {
+		dev_err(dev, "intf: Interrupt configuration failed\n");
+		goto err_config_interrupt;
+	}
+
+	ret = epf_ntb_db_bar_init(ntb);
+	if (ret) {
+		dev_err(dev, "intf: DB BAR init failed\n");
+		goto err_db_bar_init;
+	}
+
+	ret = epf_ntb_mw_bar_init(ntb);
+	if (ret) {
+		dev_err(dev, "intf: 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, "intf: 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);
+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 HOST1 and HOST2
+ *
+ * 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);
+}
+
+#define EPF_NTB_R(_name)						\
+static ssize_t epf_ntb_##_name##_show(struct config_item *item,		\
+				      char *page)			\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+									\
+	return sprintf(page, "%d\n", ntb->_name);			\
+}
+
+#define EPF_NTB_W(_name)						\
+static ssize_t epf_ntb_##_name##_store(struct config_item *item,	\
+				       const char *page, size_t len)	\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	u32 val;							\
+	int ret;							\
+									\
+	ret = kstrtou32(page, 0, &val);					\
+	if (ret)							\
+		return ret;						\
+									\
+	ntb->_name = val;						\
+									\
+	return len;							\
+}
+
+#define EPF_NTB_MW_R(_name)						\
+static ssize_t epf_ntb_##_name##_show(struct config_item *item,		\
+				      char *page)			\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	int win_no;							\
+									\
+	sscanf(#_name, "mw%d", &win_no);				\
+									\
+	return sprintf(page, "%lld\n", ntb->mws_size[win_no - 1]);	\
+}
+
+#define EPF_NTB_MW_W(_name)						\
+static ssize_t epf_ntb_##_name##_store(struct config_item *item,	\
+				       const char *page, size_t len)	\
+{									\
+	struct config_group *group = to_config_group(item);		\
+	struct epf_ntb *ntb = to_epf_ntb(group);			\
+	struct device *dev = &ntb->epf->dev;				\
+	int win_no;							\
+	u64 val;							\
+	int ret;							\
+									\
+	ret = kstrtou64(page, 0, &val);					\
+	if (ret)							\
+		return ret;						\
+									\
+	if (sscanf(#_name, "mw%d", &win_no) != 1)			\
+		return -EINVAL;						\
+									\
+	if (ntb->num_mws < win_no) {					\
+		dev_err(dev, "Invalid num_nws: %d value\n", ntb->num_mws); \
+		return -EINVAL;						\
+	}								\
+									\
+	ntb->mws_size[win_no - 1] = val;				\
+									\
+	return len;							\
+}
+
+static ssize_t epf_ntb_num_mws_store(struct config_item *item,
+				     const char *page, size_t len)
+{
+	struct config_group *group = to_config_group(item);
+	struct epf_ntb *ntb = to_epf_ntb(group);
+	u32 val;
+	int ret;
+
+	ret = kstrtou32(page, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > MAX_MW)
+		return -EINVAL;
+
+	ntb->num_mws = val;
+
+	return len;
+}
+
+EPF_NTB_R(spad_count)
+EPF_NTB_W(spad_count)
+EPF_NTB_R(db_count)
+EPF_NTB_W(db_count)
+EPF_NTB_R(num_mws)
+EPF_NTB_R(vbus_number)
+EPF_NTB_W(vbus_number)
+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);
+
+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,
+	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;
+}
+
+/*==== virtual PCI bus driver, which only load virutal ntb pci driver ====*/
+
+#define VPCI_BUS_NUM 0x10
+
+uint32_t pci_space[] = {
+	(VNTB_VID | (VNTB_PID << 16)),	//DeviceID, Vendor ID
+	0,		// status, Command
+	0xffffffff,	// Class code, subclass, prog if, 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 point
+	0,		//Subsystem ID Subystem vendor id
+	0,		//ROM Base Address
+	0,		//Reserved, Cap. Point
+	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, ((uint8_t *)pci_space) + where, size);
+		return 0;
+	}
+	return -1;
+}
+
+static int pci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val)
+{
+	return 0;
+}
+
+struct pci_ops vpci_ops = {
+	.read = pci_read,
+	.write = pci_write,
+};
+
+static int vpci_bus(void *sysdata)
+{
+	struct pci_bus *vpci_bus;
+
+	vpci_bus = pci_scan_bus(VPCI_BUS_NUM, &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 * 4;
+	u32 val;
+	void __iomem *base = ntb->reg;
+
+	val = readl(base + off + ct + idx * 4);
+	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 * 4;
+	void __iomem *base = ntb->reg;
+
+	writel(val, base + off + ct + idx * 4);
+	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 = ntb->reg;
+	u32 val;
+
+	val = readl(base + off + idx * 4);
+	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 = ntb->reg;
+
+	writel(val, base + off + idx * 4);
+	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, "intf: Failed to raise IRQ\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+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 -1;
+	}
+
+	ret = ntb_register_device(&ndev->ntb);
+	if (ret) {
+		dev_err(dev, "Failed to register NTB device\n");
+		goto err_register_dev;
+	}
+
+	dev_info(dev, "PCI Virtual NTB driver loaded\n");
+	return 0;
+
+err_register_dev:
+	return -1;
+}
+
+static const struct pci_device_id pci_vntb_table[] = {
+	{
+		PCI_DEVICE(VNTB_VID, VNTB_PID),
+	},
+	{},
+};
+
+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.
+ */
+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);
+
+	if (pci_register_driver(&vntb_pci_driver)) {
+		dev_err(dev, "failure register vntb pci driver\n");
+		goto err_bar_alloc;
+	}
+
+	vpci_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
+ *
+ * Probe NTB function driver when endpoint function bus detects a NTB
+ * endpoint function.
+ */
+static int epf_ntb_probe(struct pci_epf *epf)
+{
+	struct epf_ntb *ntb;
+	struct device *dev;
+
+	dev = &epf->dev;
+
+	ntb = devm_kzalloc(dev, sizeof(*ntb), GFP_KERNEL);
+	if (!ntb)
+		return -ENOMEM;
+
+	epf->header = &epf_ntb_header;
+	ntb->epf = epf;
+	epf_set_drvdata(epf, ntb);
+
+	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");