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+..  BSD LICENSE
+    Copyright(c) 2015 IGEL Co.,Ltd. All rights reserved.
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+    * Neither the name of IGEL Co.,Ltd. nor the names of its
+    contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Port Hotplug Framework
+======================
+
+The Port Hotplug Framework provides DPDK applications with the ability to
+attach and detach ports at runtime. Because the framework depends on PMD
+implementation, the ports that PMDs cannot handle are out of scope of this
+framework. Furthermore, after detaching a port from a DPDK application, the
+framework doesn't provide a way for removing the devices from the system.
+For the ports backed by a physical NIC, the kernel will need to support PCI
+Hotplug feature.
+
+Overview
+--------
+
+The basic requirements of the Port Hotplug Framework are:
+
+*       DPDK applications that use the Port Hotplug Framework must manage their
+        own ports.
+
+        The Port Hotplug Framework is implemented to allow DPDK applications to
+        manage ports. For example, when DPDK applications call the port attach
+        function, the attached port number is returned. DPDK applications can
+        also detach the port by port number.
+
+*       Kernel support is needed for attaching or detaching physical device
+        ports.
+
+        To attach new physical device ports, the device will be recognized by
+        userspace driver I/O framework in kernel at first. Then DPDK
+        applications can call the Port Hotplug functions to attach the ports.
+        For detaching, steps are vice versa.
+
+*       Before detaching, they must be stopped and closed.
+
+        DPDK applications must call "rte_eth_dev_stop()" and
+        "rte_eth_dev_close()" APIs before detaching ports. These functions will
+        start finalization sequence of the PMDs.
+
+*       The framework doesn't affect legacy DPDK applications behavior.
+
+        If the Port Hotplug functions aren't called, all legacy DPDK apps can
+        still work without modifications.
+
+Port Hotplug API overview
+-------------------------
+
+*       Attaching a port
+
+        "rte_eth_dev_attach()" API attaches a port to DPDK application, and
+        returns the attached port number. Before calling the API, the device
+        should be recognized by an userspace driver I/O framework. The API
+        receives a pci address like "0000:01:00.0" or a virtual device name
+        like "eth_pcap0,iface=eth0". In the case of virtual device name, the
+        format is the same as the general "--vdev" option of DPDK.
+
+*       Detaching a port
+
+        "rte_eth_dev_detach()" API detaches a port from DPDK application, and
+        returns a pci address of the detached device or a virtual device name
+        of the device.
+
+Reference
+---------
+
+        "testpmd" supports the Port Hotplug Framework.
+
+Limitations
+-----------
+
+*       The Port Hotplug APIs are not thread safe.
+
+*       The framework can only be enabled with Linux. BSD is not supported.
+
+*       To detach a port, the port should be backed by a device that igb_uio
+        manages. VFIO is not supported.
+
+*       Not all PMDs support detaching feature.
+        To know whether a PMD can support detaching, search for the
+        "RTE_PCI_DRV_DETACHABLE" flag in PMD implementation. If the flag is
+        defined in the PMD, detaching is supported.