Merge tag 'usb-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB updates from Greg KH:
 "Here is the big USB patchset for 4.6-rc1.

  The normal mess is here, gadget and xhci fixes and updates, and lots
  of other driver updates and cleanups as well.  Full details are in the
  shortlog.

  All have been in linux-next for a while with no reported issues"

* tag 'usb-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (266 commits)
  USB: core: let USB device know device node
  usb: devio: Add ioctl to disallow detaching kernel USB drivers.
  usb: gadget: f_acm: Fix configfs attr name
  usb: udc: lpc32xx: remove USB PLL and USB OTG clock management
  usb: udc: lpc32xx: remove direct access to clock controller registers
  usb: udc: lpc32xx: switch to clock prepare/unprepare model
  usb: renesas_usbhs: gadget: fix giveback status code in usbhsg_pipe_disable()
  usb: gadget: renesas_usb3: Use ARCH_RENESAS
  usb: dwc2: Fix issues in dwc2_complete_non_isoc_xfer_ddma()
  usb: dwc2: Add support for Lantiq ARX and XRX SoCs
  usb: phy: generic: Handle late registration of gadget
  usb: gadget: bdc_udc: fix race condition in bdc_udc_exit()
  usb: musb: core: added missing const qualifier to musb_hdrc_platform_data::config
  usb: dwc2: Move host-specific core functions into hcd.c
  usb: dwc2: Move register save and restore functions
  usb: dwc2: Use kmem_cache_free()
  usb: dwc2: host: If using uframe scheduler, end splits better
  usb: dwc2: host: Totally redo the microframe scheduler
  usb: dwc2: host: Properly set even/odd frame
  usb: dwc2: host: Add dwc2_hcd_get_future_frame_number() call
  ...

12 files changed, 616 insertions, 19 deletions

diff --git a/Documentation/DocBook/usb.tmpl b/Documentation/DocBook/usb.tmpl
index 4cd5b2cd0f3d..bc776be0f19c 100644
--- a/Documentation/DocBook/usb.tmpl
+++ b/Documentation/DocBook/usb.tmpl
@@ -732,6 +732,18 @@ usbdev_ioctl (int fd, int ifno, unsigned request, void *param)
 		    or SET_INTERFACE.
 		    </para></warning></listitem></varlistentry>
 
+		<varlistentry><term>USBDEVFS_DROP_PRIVILEGES</term>
+		    <listitem><para>This is used to relinquish the ability
+		    to do certain operations which are considered to be
+		    privileged on a usbfs file descriptor.
+		    This includes claiming arbitrary interfaces, resetting
+		    a device on which there are currently claimed interfaces
+		    from other users, and issuing USBDEVFS_IOCTL calls.
+		    The ioctl parameter is a 32 bit mask of interfaces
+		    the user is allowed to claim on this file descriptor.
+		    You may issue this ioctl more than one time to narrow
+		    said mask.
+		    </para></listitem></varlistentry>
 		</variablelist>
 
 		</sect2>
diff --git a/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
index 2390e4e9c84c..eaf7e9b7ce6b 100644
--- a/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
+++ b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
@@ -7,33 +7,26 @@ Required properties:
 - compatible: "renesas,usb2-phy-r8a7795" if the device is a part of an R8A7795
 	      SoC.
 - reg: offset and length of the partial USB 2.0 Host register block.
-- reg-names: must be "usb2_host".
 - clocks: clock phandle and specifier pair(s).
 - #phy-cells: see phy-bindings.txt in the same directory, must be <0>.
 
 Optional properties:
 To use a USB channel where USB 2.0 Host and HSUSB (USB 2.0 Peripheral) are
-combined, the device tree node should set HSUSB properties to reg and reg-names
-properties. This is because HSUSB has registers to select USB 2.0 host or
-peripheral at that channel:
-- reg: offset and length of the partial HSUSB register block.
-- reg-names: must be "hsusb".
+combined, the device tree node should set interrupt properties to use the
+channel as USB OTG:
 - interrupts: interrupt specifier for the PHY.
 
 Example (R-Car H3):
 
 	usb-phy@ee080200 {
 		compatible = "renesas,usb2-phy-r8a7795";
-		reg = <0 0xee080200 0 0x700>, <0 0xe6590100 0 0x100>;
-		reg-names = "usb2_host", "hsusb";
+		reg = <0 0xee080200 0 0x700>;
 		interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>;
-		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>,
-			 <&mstp7_clks R8A7795_CLK_HSUSB>;
+		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>;
 	};
 
 	usb-phy@ee0a0200 {
 		compatible = "renesas,usb2-phy-r8a7795";
 		reg = <0 0xee0a0200 0 0x700>;
-		reg-names = "usb2_host";
 		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>;
 	};
diff --git a/Documentation/devicetree/bindings/phy/rockchip-dp-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-dp-phy.txt
new file mode 100644
index 000000000000..50c4f9b00adf
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/rockchip-dp-phy.txt
@@ -0,0 +1,22 @@
+Rockchip specific extensions to the Analogix Display Port PHY
+------------------------------------
+
+Required properties:
+- compatible : should be one of the following supported values:
+	 - "rockchip.rk3288-dp-phy"
+- clocks: from common clock binding: handle to dp clock.
+	of memory mapped region.
+- clock-names: from common clock binding:
+	Required elements: "24m"
+- rockchip,grf: phandle to the syscon managing the "general register files"
+- #phy-cells : from the generic PHY bindings, must be 0;
+
+Example:
+
+edp_phy: edp-phy {
+	compatible = "rockchip,rk3288-dp-phy";
+	rockchip,grf = <&grf>;
+	clocks = <&cru SCLK_EDP_24M>;
+	clock-names = "24m";
+	#phy-cells = <0>;
+};
diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
new file mode 100644
index 000000000000..61916f15a949
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
@@ -0,0 +1,19 @@
+Rockchip EMMC PHY
+-----------------------
+
+Required properties:
+ - compatible: rockchip,rk3399-emmc-phy
+ - rockchip,grf : phandle to the syscon managing the "general
+   register files"
+ - #phy-cells: must be 0
+ - reg: PHY configure reg address offset in "general
+   register files"
+
+Example:
+
+emmcphy: phy {
+	compatible = "rockchip,rk3399-emmc-phy";
+	rockchip,grf = <&grf>;
+	reg = <0xf780>;
+	#phy-cells = <0>;
+};
diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
index 781296bfbe4f..1084e2bcbe1c 100644
--- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
+++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
@@ -2,7 +2,14 @@
 
 Required properties:
 - compatible: should be one of:
+	"fsl,imx23-usb"
 	"fsl,imx27-usb"
+	"fsl,imx28-usb"
+	"fsl,imx6q-usb"
+	"fsl,imx6sl-usb"
+	"fsl,imx6sx-usb"
+	"fsl,imx6ul-usb"
+	"fsl,imx7d-usb"
 	"lsi,zevio-usb"
 	"qcom,ci-hdrc"
 	"chipidea,usb2"
@@ -53,6 +60,22 @@ Optional properties:
   be specified.
 - phy-clkgate-delay-us: the delay time (us) between putting the PHY into
   low power mode and gating the PHY clock.
+- non-zero-ttctrl-ttha: after setting this property, the value of register
+  ttctrl.ttha will be 0x7f; if not, the value will be 0x0, this is the default
+  value. It needs to be very carefully for setting this property, it is
+  recommended that consult with your IC engineer before setting this value.
+  On the most of chipidea platforms, the "usage_tt" flag at RTL is 0, so this
+  property only affects siTD.
+  If this property is not set, the max packet size is 1023 bytes, and if
+  the total of packet size for pervious transactions are more than 256 bytes,
+  it can't accept any transactions within this frame. The use case is single
+  transaction, but higher frame rate.
+  If this property is set, the max packet size is 188 bytes, it can handle
+  more transactions than above case, it can accept transactions until it
+  considers the left room size within frame is less than 188 bytes, software
+  needs to make sure it does not send more than 90%
+  maximum_periodic_data_per_frame. The use case is multiple transactions, but
+  less frame rate.
 
 i.mx specific properties
 - fsl,usbmisc: phandler of non-core register device, with one
diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
index 221368207ca4..20a68bf2b4e7 100644
--- a/Documentation/devicetree/bindings/usb/dwc2.txt
+++ b/Documentation/devicetree/bindings/usb/dwc2.txt
@@ -8,6 +8,8 @@ Required properties:
   - rockchip,rk3066-usb: The DWC2 USB controller instance in the rk3066 Soc;
   - "rockchip,rk3188-usb", "rockchip,rk3066-usb", "snps,dwc2": for rk3188 Soc;
   - "rockchip,rk3288-usb", "rockchip,rk3066-usb", "snps,dwc2": for rk3288 Soc;
+  - "lantiq,arx100-usb": The DWC2 USB controller instance in Lantiq ARX SoCs;
+  - "lantiq,xrx200-usb": The DWC2 USB controller instance in Lantiq XRX SoCs;
   - snps,dwc2: A generic DWC2 USB controller with default parameters.
 - reg : Should contain 1 register range (address and length)
 - interrupts : Should contain 1 interrupt
diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
new file mode 100644
index 000000000000..1c35e7b665e1
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -0,0 +1,28 @@
+Generic USB Device Properties
+
+Usually, we only use device tree for hard wired USB device.
+The reference binding doc is from:
+http://www.firmware.org/1275/bindings/usb/usb-1_0.ps
+
+Required properties:
+- compatible: usbVID,PID. The textual representation of VID, PID shall
+  be in lower case hexadecimal with leading zeroes suppressed. The
+  other compatible strings from the above standard binding could also
+  be used, but a device adhering to this binding may leave out all except
+  for usbVID,PID.
+- reg: the port number which this device is connecting to, the range
+  is 1-31.
+
+Example:
+
+&usb1 {
+	status = "okay";
+
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	hub: genesys@1 {
+		compatible = "usb5e3,608";
+		reg = <1>;
+	};
+}
diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
index 082573289f1e..6a17aa85c4d5 100644
--- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
@@ -1,10 +1,23 @@
 USB xHCI controllers
 
 Required properties:
-  - compatible: should be one of "generic-xhci",
-    "marvell,armada-375-xhci", "marvell,armada-380-xhci",
-    "renesas,xhci-r8a7790", "renesas,xhci-r8a7791", "renesas,xhci-r8a7793",
-    "renesas,xhci-r8a7795" (deprecated: "xhci-platform").
+  - compatible: should be one or more of
+
+    - "generic-xhci" for generic XHCI device
+    - "marvell,armada-375-xhci" for Armada 375 SoCs
+    - "marvell,armada-380-xhci" for Armada 38x SoCs
+    - "renesas,xhci-r8a7790" for r8a7790 SoC
+    - "renesas,xhci-r8a7791" for r8a7791 SoC
+    - "renesas,xhci-r8a7793" for r8a7793 SoC
+    - "renesas,xhci-r8a7795" for r8a7795 SoC
+    - "renesas,rcar-gen2-xhci" for a generic R-Car Gen2 compatible device
+    - "renesas,rcar-gen3-xhci" for a generic R-Car Gen3 compatible device
+    - "xhci-platform" (deprecated)
+
+    When compatible with the generic version, nodes must list the
+    SoC-specific version corresponding to the platform first
+    followed by the generic version.
+
   - reg: should contain address and length of the standard XHCI
     register set for the device.
   - interrupts: one XHCI interrupt should be described here.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 85b280de7aa8..0ee46a8f6401 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3533,6 +3533,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 		on	Mark read-only kernel memory as read-only (default).
 		off	Leave read-only kernel memory writable for debugging.
 
+	rockchip.usb_uart
+			Enable the uart passthrough on the designated usb port
+			on Rockchip SoCs. When active, the signals of the
+			debug-uart get routed to the D+ and D- pins of the usb
+			port and the regular usb controller gets disabled.
+
 	root=		[KNL] Root filesystem
 			See name_to_dev_t comment in init/do_mounts.c.
 
diff --git a/Documentation/usb/chipidea.txt b/Documentation/usb/chipidea.txt
index 05f735a1b5a5..678741b0f213 100644
--- a/Documentation/usb/chipidea.txt
+++ b/Documentation/usb/chipidea.txt
@@ -26,16 +26,17 @@ cat /sys/kernel/debug/ci_hdrc.0/registers
    On B-device:
    echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 
-   if HNP polling is not supported, also need:
-   On A-device:
-   echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
-
    B-device should take host role and enumrate A-device.
 
 4) A-device switch back to host.
    On B-device:
    echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 
+   or, by introducing HNP polling, B-Host can know when A-peripheral wish
+   to be host role, so this role switch also can be trigged in A-peripheral
+   side by answering the polling from B-Host, this can be done on A-device:
+   echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
+
    A-device should switch back to host and enumrate B-device.
 
 5) Remove B-device(unplug micro B plug) and insert again in 10 seconds,
diff --git a/Documentation/usb/usbdevfs-drop-permissions.c b/Documentation/usb/usbdevfs-drop-permissions.c
new file mode 100644
index 000000000000..6b8da6ef0c9a
--- /dev/null
+++ b/Documentation/usb/usbdevfs-drop-permissions.c
@@ -0,0 +1,120 @@
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
+#include <unistd.h>
+
+#include <linux/usbdevice_fs.h>
+
+/* For building without an updated set of headers */
+#ifndef USBDEVFS_DROP_PRIVILEGES
+#define USBDEVFS_DROP_PRIVILEGES		_IOW('U', 30, __u32)
+#define USBDEVFS_CAP_DROP_PRIVILEGES		0x40
+#endif
+
+void drop_privileges(int fd, uint32_t mask)
+{
+	int res;
+
+	res = ioctl(fd, USBDEVFS_DROP_PRIVILEGES, &mask);
+	if (res)
+		printf("ERROR: USBDEVFS_DROP_PRIVILEGES returned %d\n", res);
+	else
+		printf("OK: privileges dropped!\n");
+}
+
+void reset_device(int fd)
+{
+	int res;
+
+	res = ioctl(fd, USBDEVFS_RESET);
+	if (!res)
+		printf("OK: USBDEVFS_RESET succeeded\n");
+	else
+		printf("ERROR: reset failed! (%d - %s)\n",
+		       -res, strerror(-res));
+}
+
+void claim_some_intf(int fd)
+{
+	int i, res;
+
+	for (i = 0; i < 4; i++) {
+		res = ioctl(fd, USBDEVFS_CLAIMINTERFACE, &i);
+		if (!res)
+			printf("OK: claimed if %d\n", i);
+		else
+			printf("ERROR claiming if %d (%d - %s)\n",
+			       i, -res, strerror(-res));
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	uint32_t mask, caps;
+	int c, fd;
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("Failed to open file\n");
+		goto err_fd;
+	}
+
+	/*
+	 * check if dropping privileges is supported,
+	 * bail on systems where the capability is not present
+	 */
+	ioctl(fd, USBDEVFS_GET_CAPABILITIES, &caps);
+	if (!(caps & USBDEVFS_CAP_DROP_PRIVILEGES)) {
+		printf("DROP_PRIVILEGES not supported\n");
+		goto err;
+	}
+
+	/*
+	 * Drop privileges but keep the ability to claim all
+	 * free interfaces (i.e., those not used by kernel drivers)
+	 */
+	drop_privileges(fd, -1U);
+
+	printf("Available options:\n"
+		"[0] Exit now\n"
+		"[1] Reset device. Should fail if device is in use\n"
+		"[2] Claim 4 interfaces. Should succeed where not in use\n"
+		"[3] Narrow interface permission mask\n"
+		"Which option shall I run?: ");
+
+	while (scanf("%d", &c) == 1) {
+		switch (c) {
+		case 0:
+			goto exit;
+		case 1:
+			reset_device(fd);
+			break;
+		case 2:
+			claim_some_intf(fd);
+			break;
+		case 3:
+			printf("Insert new mask: ");
+			scanf("%x", &mask);
+			drop_privileges(fd, mask);
+			break;
+		default:
+			printf("I don't recognize that\n");
+		}
+
+		printf("Which test shall I run next?: ");
+	}
+
+exit:
+	close(fd);
+	return 0;
+
+err:
+	close(fd);
+err_fd:
+	return 1;
+}
diff --git a/Documentation/usb/usbip_protocol.txt b/Documentation/usb/usbip_protocol.txt
new file mode 100644
index 000000000000..16b6fe27284c
--- /dev/null
+++ b/Documentation/usb/usbip_protocol.txt
@@ -0,0 +1,358 @@
+PRELIMINARY DRAFT, MAY CONTAIN MISTAKES!
+28 Jun 2011
+
+The USB/IP protocol follows a server/client architecture. The server exports the
+USB devices and the clients imports them. The device driver for the exported
+USB device runs on the client machine.
+
+The client may ask for the list of the exported USB devices. To get the list the
+client opens a TCP/IP connection towards the server, and sends an OP_REQ_DEVLIST
+packet on top of the TCP/IP connection (so the actual OP_REQ_DEVLIST may be sent
+in one or more pieces at the low level transport layer). The server sends back
+the OP_REP_DEVLIST packet which lists the exported USB devices. Finally the
+TCP/IP connection is closed.
+
+ virtual host controller                                 usb host
+      "client"                                           "server"
+  (imports USB devices)                             (exports USB devices)
+          |                                                 |
+          |                  OP_REQ_DEVLIST                 |
+          | ----------------------------------------------> |
+          |                                                 |
+          |                  OP_REP_DEVLIST                 |
+          | <---------------------------------------------- |
+          |                                                 |
+
+Once the client knows the list of exported USB devices it may decide to use one
+of them. First the client opens a TCP/IP connection towards the server and
+sends an OP_REQ_IMPORT packet. The server replies with OP_REP_IMPORT. If the
+import was successful the TCP/IP connection remains open and will be used
+to transfer the URB traffic between the client and the server. The client may
+send two types of packets: the USBIP_CMD_SUBMIT to submit an URB, and
+USBIP_CMD_UNLINK to unlink a previously submitted URB. The answers of the
+server may be USBIP_RET_SUBMIT and USBIP_RET_UNLINK respectively.
+
+ virtual host controller                                 usb host
+      "client"                                           "server"
+  (imports USB devices)                             (exports USB devices)
+          |                                                 |
+          |                  OP_REQ_IMPORT                  |
+          | ----------------------------------------------> |
+          |                                                 |
+          |                  OP_REP_IMPORT                  |
+          | <---------------------------------------------- |
+          |                                                 |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = n)         |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_RET_SUBMIT(seqnum = n)         |
+          | <---------------------------------------------- |
+          |                        .                        |
+          |                        :                        |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = m)         |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = m+1)       |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = m+2)       |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_RET_SUBMIT(seqnum = m)         |
+          | <---------------------------------------------- |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = m+3)       |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_RET_SUBMIT(seqnum = m+1)       |
+          | <---------------------------------------------- |
+          |                                                 |
+          |            USBIP_CMD_SUBMIT(seqnum = m+4)       |
+          | ----------------------------------------------> |
+          |                                                 |
+          |            USBIP_RET_SUBMIT(seqnum = m+2)       |
+          | <---------------------------------------------- |
+          |                        .                        |
+          |                        :                        |
+          |                                                 |
+          |               USBIP_CMD_UNLINK                  |
+          | ----------------------------------------------> |
+          |                                                 |
+          |               USBIP_RET_UNLINK                  |
+          | <---------------------------------------------- |
+          |                                                 |
+
+The fields are in network (big endian) byte order meaning that the most significant
+byte (MSB) is stored at the lowest address.
+
+
+OP_REQ_DEVLIST: Retrieve the list of exported USB devices.
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 2      | 0x0100     | Binary-coded decimal USBIP version number: v1.0.0
+-----------+--------+------------+---------------------------------------------------
+ 2         | 2      | 0x8005     | Command code: Retrieve the list of exported USB
+           |        |            |   devices.
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      | 0x00000000 | Status: unused, shall be set to 0
+
+OP_REP_DEVLIST: Reply with the list of exported USB devices.
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 2      | 0x0100     | Binary-coded decimal USBIP version number: v1.0.0.
+-----------+--------+------------+---------------------------------------------------
+ 2         | 2      | 0x0005     | Reply code: The list of exported USB devices.
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      | 0x00000000 | Status: 0 for OK
+-----------+--------+------------+---------------------------------------------------
+ 8         | 4      | n          | Number of exported devices: 0 means no exported
+           |        |            |   devices.
+-----------+--------+------------+---------------------------------------------------
+ 0x0C      |        |            | From now on the exported n devices are described,
+           |        |            |   if any. If no devices are exported the message
+           |        |            |   ends with the previous "number of exported
+           |        |            |   devices" field.
+-----------+--------+------------+---------------------------------------------------
+           | 256    |            | path: Path of the device on the host exporting the
+           |        |            |   USB device, string closed with zero byte, e.g.
+           |        |            |   "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2"
+           |        |            |   The unused bytes shall be filled with zero
+           |        |            |   bytes.
+-----------+--------+------------+---------------------------------------------------
+ 0x10C     | 32     |            | busid: Bus ID of the exported device, string
+           |        |            |   closed with zero byte, e.g. "3-2". The unused
+           |        |            |   bytes shall be filled with zero bytes.
+-----------+--------+------------+---------------------------------------------------
+ 0x12C     | 4      |            | busnum
+-----------+--------+------------+---------------------------------------------------
+ 0x130     | 4      |            | devnum
+-----------+--------+------------+---------------------------------------------------
+ 0x134     | 4      |            | speed
+-----------+--------+------------+---------------------------------------------------
+ 0x138     | 2      |            | idVendor
+-----------+--------+------------+---------------------------------------------------
+ 0x13A     | 2      |            | idProduct
+-----------+--------+------------+---------------------------------------------------
+ 0x13C     | 2      |            | bcdDevice
+-----------+--------+------------+---------------------------------------------------
+ 0x13E     | 1      |            | bDeviceClass
+-----------+--------+------------+---------------------------------------------------
+ 0x13F     | 1      |            | bDeviceSubClass
+-----------+--------+------------+---------------------------------------------------
+ 0x140     | 1      |            | bDeviceProtocol
+-----------+--------+------------+---------------------------------------------------
+ 0x141     | 1      |            | bConfigurationValue
+-----------+--------+------------+---------------------------------------------------
+ 0x142     | 1      |            | bNumConfigurations
+-----------+--------+------------+---------------------------------------------------
+ 0x143     | 1      |            | bNumInterfaces
+-----------+--------+------------+---------------------------------------------------
+ 0x144     |        | m_0        | From now on each interface is described, all
+           |        |            |   together bNumInterfaces times, with the
+           |        |            |   the following 4 fields:
+-----------+--------+------------+---------------------------------------------------
+           | 1      |            | bInterfaceClass
+-----------+--------+------------+---------------------------------------------------
+ 0x145     | 1      |            | bInterfaceSubClass
+-----------+--------+------------+---------------------------------------------------
+ 0x146     | 1      |            | bInterfaceProtocol
+-----------+--------+------------+---------------------------------------------------
+ 0x147     | 1      |            | padding byte for alignment, shall be set to zero
+-----------+--------+------------+---------------------------------------------------
+ 0xC +     |        |            | The second exported USB device starts at i=1
+ i*0x138 + |        |            | with the busid field.
+ m_(i-1)*4 |        |            |
+
+OP_REQ_IMPORT: Request to import (attach) a remote USB device.
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 2      | 0x0100     | Binary-coded decimal USBIP version number: v1.0.0
+-----------+--------+------------+---------------------------------------------------
+ 2         | 2      | 0x8003     | Command code: import a remote USB device.
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      | 0x00000000 | Status: unused, shall be set to 0
+-----------+--------+------------+---------------------------------------------------
+ 8         | 32     |            | busid: the busid of the exported device on the
+           |        |            |   remote host. The possible values are taken
+           |        |            |   from the message field OP_REP_DEVLIST.busid.
+           |        |            |   A string closed with zero, the unused bytes
+           |        |            |   shall be filled with zeros.
+-----------+--------+------------+---------------------------------------------------
+
+OP_REP_IMPORT: Reply to import (attach) a remote USB device.
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 2      | 0x0100     | Binary-coded decimal USBIP version number: v1.0.0
+-----------+--------+------------+---------------------------------------------------
+ 2         | 2      | 0x0003     | Reply code: Reply to import.
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      | 0x00000000 | Status: 0 for OK
+           |        |            |         1 for error
+-----------+--------+------------+---------------------------------------------------
+ 8         |        |            | From now on comes the details of the imported
+           |        |            |   device, if the previous status field was OK (0),
+           |        |            |   otherwise the reply ends with the status field.
+-----------+--------+------------+---------------------------------------------------
+           | 256    |            | path: Path of the device on the host exporting the
+           |        |            |   USB device, string closed with zero byte, e.g.
+           |        |            |   "/sys/devices/pci0000:00/0000:00:1d.1/usb3/3-2"
+           |        |            |   The unused bytes shall be filled with zero
+           |        |            |   bytes.
+-----------+--------+------------+---------------------------------------------------
+ 0x108     | 32     |            | busid: Bus ID of the exported device, string
+           |        |            |   closed with zero byte, e.g. "3-2". The unused
+           |        |            |   bytes shall be filled with zero bytes.
+-----------+--------+------------+---------------------------------------------------
+ 0x128     | 4      |            | busnum
+-----------+--------+------------+---------------------------------------------------
+ 0x12C     | 4      |            | devnum
+-----------+--------+------------+---------------------------------------------------
+ 0x130     | 4      |            | speed
+-----------+--------+------------+---------------------------------------------------
+ 0x134     | 2      |            | idVendor
+-----------+--------+------------+---------------------------------------------------
+ 0x136     | 2      |            | idProduct
+-----------+--------+------------+---------------------------------------------------
+ 0x138     | 2      |            | bcdDevice
+-----------+--------+------------+---------------------------------------------------
+ 0x139     | 1      |            | bDeviceClass
+-----------+--------+------------+---------------------------------------------------
+ 0x13A     | 1      |            | bDeviceSubClass
+-----------+--------+------------+---------------------------------------------------
+ 0x13B     | 1      |            | bDeviceProtocol
+-----------+--------+------------+---------------------------------------------------
+ 0x13C     | 1      |            | bConfigurationValue
+-----------+--------+------------+---------------------------------------------------
+ 0x13D     | 1      |            | bNumConfigurations
+-----------+--------+------------+---------------------------------------------------
+ 0x13E     | 1      |            | bNumInterfaces
+
+USBIP_CMD_SUBMIT: Submit an URB
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 4      | 0x00000001 | command: Submit an URB
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      |            | seqnum: the sequence number of the URB to submit
+-----------+--------+------------+---------------------------------------------------
+ 8         | 4      |            | devid
+-----------+--------+------------+---------------------------------------------------
+ 0xC       | 4      |            | direction: 0: USBIP_DIR_OUT
+           |        |            |            1: USBIP_DIR_IN
+-----------+--------+------------+---------------------------------------------------
+ 0x10      | 4      |            | ep: endpoint number, possible values are: 0...15
+-----------+--------+------------+---------------------------------------------------
+ 0x14      | 4      |            | transfer_flags: possible values depend on the
+           |        |            |   URB transfer type, see below
+-----------+--------+------------+---------------------------------------------------
+ 0x18      | 4      |            | transfer_buffer_length
+-----------+--------+------------+---------------------------------------------------
+ 0x1C      | 4      |            | start_frame: specify the selected frame to
+           |        |            |   transmit an ISO frame, ignored if URB_ISO_ASAP
+           |        |            |   is specified at transfer_flags
+-----------+--------+------------+---------------------------------------------------
+ 0x20      | 4      |            | number_of_packets: number of ISO packets
+-----------+--------+------------+---------------------------------------------------
+ 0x24      | 4      |            | interval: maximum time for the request on the
+           |        |            |   server-side host controller
+-----------+--------+------------+---------------------------------------------------
+ 0x28      | 8      |            | setup: data bytes for USB setup, filled with
+           |        |            |   zeros if not used
+-----------+--------+------------+---------------------------------------------------
+ 0x30      |        |            | URB data. For ISO transfers the padding between
+           |        |            |   each ISO packets is not transmitted.
+
+
+  Allowed transfer_flags  | value      | control | interrupt | bulk     | isochronous
+ -------------------------+------------+---------+-----------+----------+-------------
+  URB_SHORT_NOT_OK        | 0x00000001 | only in | only in   | only in  | no
+  URB_ISO_ASAP            | 0x00000002 | no      | no        | no       | yes
+  URB_NO_TRANSFER_DMA_MAP | 0x00000004 | yes     | yes       | yes      | yes
+  URB_NO_FSBR             | 0x00000020 | yes     | no        | no       | no
+  URB_ZERO_PACKET         | 0x00000040 | no      | no        | only out | no
+  URB_NO_INTERRUPT        | 0x00000080 | yes     | yes       | yes      | yes
+  URB_FREE_BUFFER         | 0x00000100 | yes     | yes       | yes      | yes
+  URB_DIR_MASK            | 0x00000200 | yes     | yes       | yes      | yes
+
+
+USBIP_RET_SUBMIT: Reply for submitting an URB
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 4      | 0x00000003 | command
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      |            | seqnum: URB sequence number
+-----------+--------+------------+---------------------------------------------------
+ 8         | 4      |            | devid
+-----------+--------+------------+---------------------------------------------------
+ 0xC       | 4      |            | direction: 0: USBIP_DIR_OUT
+           |        |            |            1: USBIP_DIR_IN
+-----------+--------+------------+---------------------------------------------------
+ 0x10      | 4      |            | ep: endpoint number
+-----------+--------+------------+---------------------------------------------------
+ 0x14      | 4      |            | status: zero for successful URB transaction,
+           |        |            |   otherwise some kind of error happened.
+-----------+--------+------------+---------------------------------------------------
+ 0x18      | 4      | n          | actual_length: number of URB data bytes
+-----------+--------+------------+---------------------------------------------------
+ 0x1C      | 4      |            | start_frame: for an ISO frame the actually
+           |        |            |   selected frame for transmit.
+-----------+--------+------------+---------------------------------------------------
+ 0x20      | 4      |            | number_of_packets
+-----------+--------+------------+---------------------------------------------------
+ 0x24      | 4      |            | error_count
+-----------+--------+------------+---------------------------------------------------
+ 0x28      | 8      |            | setup: data bytes for USB setup, filled with
+           |        |            |   zeros if not used
+-----------+--------+------------+---------------------------------------------------
+ 0x30      | n      |            | URB data bytes. For ISO transfers the padding
+           |        |            |   between each ISO packets is not transmitted.
+
+USBIP_CMD_UNLINK: Unlink an URB
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 4      | 0x00000002 | command: URB unlink command
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      |            | seqnum: URB sequence number to unlink: FIXME: is this so?
+-----------+--------+------------+---------------------------------------------------
+ 8         | 4      |            | devid
+-----------+--------+------------+---------------------------------------------------
+ 0xC       | 4      |            | direction: 0: USBIP_DIR_OUT
+           |        |            |            1: USBIP_DIR_IN
+-----------+--------+------------+---------------------------------------------------
+ 0x10      | 4      |            | ep: endpoint number: zero
+-----------+--------+------------+---------------------------------------------------
+ 0x14      | 4      |            | seqnum: the URB sequence number given previously
+           |        |            |   at USBIP_CMD_SUBMIT.seqnum field
+-----------+--------+------------+---------------------------------------------------
+ 0x30      | n      |            | URB data bytes. For ISO transfers the padding
+           |        |            |   between each ISO packets is not transmitted.
+
+USBIP_RET_UNLINK: Reply for URB unlink
+
+ Offset    | Length | Value      | Description
+-----------+--------+------------+---------------------------------------------------
+ 0         | 4      | 0x00000004 | command: reply for the URB unlink command
+-----------+--------+------------+---------------------------------------------------
+ 4         | 4      |            | seqnum: the unlinked URB sequence number
+-----------+--------+------------+---------------------------------------------------
+ 8         | 4      |            | devid
+-----------+--------+------------+---------------------------------------------------
+ 0xC       | 4      |            | direction: 0: USBIP_DIR_OUT
+           |        |            |            1: USBIP_DIR_IN
+-----------+--------+------------+---------------------------------------------------
+ 0x10      | 4      |            | ep: endpoint number
+-----------+--------+------------+---------------------------------------------------
+ 0x14      | 4      |            | status: This is the value contained in the
+           |        |            |   urb->status in the URB completition handler.
+           |        |            |   FIXME: a better explanation needed.
+-----------+--------+------------+---------------------------------------------------
+ 0x30      | n      |            | URB data bytes. For ISO transfers the padding
+           |        |            |   between each ISO packets is not transmitted.