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[Xen-devel] [PATCH 2/4] usb: Introduce Xen pvUSB frontend



Introduces the Xen pvUSB frontend. With pvUSB it is possible for a Xen
domU to communicate with a USB device assigned to that domU. The
communication is all done via the pvUSB backend in a driver domain
(usually Dom0) which is owner of the physical device.

The code is taken from the pvUSB implementation in Xen done by Fujitsu
based on Linux kernel 2.6.18.

Changes from the original version are:
- port to upstream kernel
- put all code in just one source file
- move module to appropriate location in kernel tree
- adapt to Linux style guide
- minor code modifications to increase readability

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/usb/Kconfig            |    2 +
 drivers/usb/Makefile           |    2 +
 drivers/usb/xen/Kconfig        |   10 +
 drivers/usb/xen/Makefile       |    5 +
 drivers/usb/xen/xen-usbfront.c | 1634 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 1653 insertions(+)
 create mode 100644 drivers/usb/xen/Kconfig
 create mode 100644 drivers/usb/xen/Makefile
 create mode 100644 drivers/usb/xen/xen-usbfront.c

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 8ed451d..de998f1 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -94,6 +94,8 @@ source "drivers/usb/image/Kconfig"
 
 source "drivers/usb/usbip/Kconfig"
 
+source "drivers/usb/xen/Kconfig"
+
 endif
 
 source "drivers/usb/musb/Kconfig"
diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
index 2f1e2aa..2676ef6 100644
--- a/drivers/usb/Makefile
+++ b/drivers/usb/Makefile
@@ -62,3 +62,5 @@ obj-$(CONFIG_USB_GADGET)      += gadget/
 obj-$(CONFIG_USB_COMMON)       += common/
 
 obj-$(CONFIG_USBIP_CORE)       += usbip/
+
+obj-$(CONFIG_XEN_USB_FRONTEND) += xen/
diff --git a/drivers/usb/xen/Kconfig b/drivers/usb/xen/Kconfig
new file mode 100644
index 0000000..5d995477
--- /dev/null
+++ b/drivers/usb/xen/Kconfig
@@ -0,0 +1,10 @@
+config XEN_USB_FRONTEND
+       tristate "Xen USB frontend driver"
+       depends on XEN
+       default m
+       select XEN_XENBUS_FRONTEND
+       help
+         The Xen USB frontend driver allows the kernel to access USB Devices
+         within another guest OS (usually Dom0).
+         Only needed if the kernel is running in a Xen guest and generic
+         access to a USB device is needed.
diff --git a/drivers/usb/xen/Makefile b/drivers/usb/xen/Makefile
new file mode 100644
index 0000000..4568c26
--- /dev/null
+++ b/drivers/usb/xen/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for Xen pvUSB drivers
+#
+
+obj-$(CONFIG_XEN_USB_FRONTEND)         += xen-usbfront.o
diff --git a/drivers/usb/xen/xen-usbfront.c b/drivers/usb/xen/xen-usbfront.c
new file mode 100644
index 0000000..f49e8e9
--- /dev/null
+++ b/drivers/usb/xen/xen-usbfront.c
@@ -0,0 +1,1634 @@
+/*
+ * xen-usbfront.c
+ *
+ * Xen USB Virtual Host Controller driver
+ *
+ * Copyright (C) 2009, FUJITSU LABORATORIES LTD.
+ * Author: Noboru Iwamatsu <n_iwamatsu@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * or, by your choice,
+ *
+ * When distributed separately from the Linux kernel or incorporated into
+ * other software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/list.h>
+#include <linux/usb/hcd.h>
+#include <linux/io.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <xen/page.h>
+
+#include <xen/interface/io/usbif.h>
+
+/* Private per-URB data */
+struct urb_priv {
+       struct list_head list;
+       struct urb *urb;
+       int req_id;             /* RING_REQUEST id for submitting */
+       int unlink_req_id;      /* RING_REQUEST id for unlinking */
+       int status;
+       unsigned unlinked:1;    /* dequeued marker */
+};
+
+/* virtual roothub port status */
+struct rhport_status {
+       u32 status;
+       unsigned resuming:1;            /* in resuming */
+       unsigned c_connection:1;        /* connection changed */
+       unsigned long timeout;
+};
+
+/* status of attached device */
+struct vdevice_status {
+       int devnum;
+       enum usb_device_state status;
+        enum usb_device_speed speed;
+};
+
+/* RING request shadow */
+struct usb_shadow {
+       struct usbif_urb_request req;
+       struct urb *urb;
+};
+
+struct usbfront_info {
+       /* Virtual Host Controller has 4 urb queues */
+       struct list_head pending_submit_list;
+       struct list_head pending_unlink_list;
+       struct list_head in_progress_list;
+       struct list_head giveback_waiting_list;
+
+       spinlock_t lock;
+
+       /* timer that kick pending and giveback waiting urbs */
+       struct timer_list watchdog;
+       unsigned long actions;
+
+       /* virtual root hub */
+       int rh_numports;
+       struct rhport_status ports[USB_MAXCHILDREN];
+       struct vdevice_status devices[USB_MAXCHILDREN];
+
+       /* Xen related staff */
+       struct xenbus_device *xbdev;
+       int urb_ring_ref;
+       int conn_ring_ref;
+       struct usbif_urb_front_ring urb_ring;
+       struct usbif_conn_front_ring conn_ring;
+
+       unsigned int evtchn;
+       unsigned int irq;
+       struct usb_shadow shadow[USB_URB_RING_SIZE];
+       unsigned long shadow_free;
+};
+
+#define GRANT_INVALID_REF 0
+
+#define XENHCD_RING_JIFFIES (HZ/200)
+#define XENHCD_SCAN_JIFFIES 1
+
+enum xenhcd_timer_action {
+       TIMER_RING_WATCHDOG,
+       TIMER_SCAN_PENDING_URBS,
+};
+
+static struct kmem_cache *usbfront_urbp_cachep;
+
+static inline struct usbfront_info *usbfront_hcd_to_info(struct usb_hcd *hcd)
+{
+       return (struct usbfront_info *)hcd->hcd_priv;
+}
+
+static inline struct usb_hcd *usbfront_info_to_hcd(struct usbfront_info *info)
+{
+       return container_of((void *)info, struct usb_hcd, hcd_priv);
+}
+
+static inline void usbfront_timer_action_done(struct usbfront_info *info,
+                                             enum xenhcd_timer_action action)
+{
+       clear_bit(action, &info->actions);
+}
+
+static void usbfront_timer_action(struct usbfront_info *info,
+                                 enum xenhcd_timer_action action)
+{
+       if (timer_pending(&info->watchdog) &&
+           test_bit(TIMER_SCAN_PENDING_URBS, &info->actions))
+               return;
+
+       if (!test_and_set_bit(action, &info->actions)) {
+               unsigned long t;
+
+               switch (action) {
+               case TIMER_RING_WATCHDOG:
+                       t = XENHCD_RING_JIFFIES;
+                       break;
+               default:
+                       t = XENHCD_SCAN_JIFFIES;
+                       break;
+               }
+               mod_timer(&info->watchdog, t + jiffies);
+       }
+}
+
+static ssize_t usbfront_show_statistics(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct usb_hcd *hcd;
+       struct usbfront_info *info;
+       unsigned long flags;
+       unsigned size;
+
+       hcd = dev_get_drvdata(dev);
+       info = usbfront_hcd_to_info(hcd);
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       size = scnprintf(buf, PAGE_SIZE, "bus %s, device %s\n%s\n"
+                        "xenhcd, hcd state %d\n",
+                        hcd->self.controller->bus->name,
+                        dev_name(hcd->self.controller), hcd->product_desc,
+                        hcd->state);
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       return size;
+}
+
+static DEVICE_ATTR(statistics, S_IRUGO, usbfront_show_statistics, NULL);
+
+static void usbfront_create_debug_file(struct usbfront_info *info)
+{
+       struct device *dev = usbfront_info_to_hcd(info)->self.controller;
+
+       if (device_create_file(dev, &dev_attr_statistics))
+               pr_warn("statistics file not created for %s\n",
+                       usbfront_info_to_hcd(info)->self.bus_name);
+}
+
+static void usbfront_remove_debug_file(struct usbfront_info *info)
+{
+       struct device *dev = usbfront_info_to_hcd(info)->self.controller;
+
+       device_remove_file(dev, &dev_attr_statistics);
+}
+
+/*
+ * set virtual port connection status
+ */
+static void usbfront_set_connect_state(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       if (info->ports[port].status & USB_PORT_STAT_POWER) {
+               switch (info->devices[port].speed) {
+               case USB_SPEED_UNKNOWN:
+                       info->ports[port].status &=
+                               ~(USB_PORT_STAT_CONNECTION |
+                                 USB_PORT_STAT_ENABLE |
+                                 USB_PORT_STAT_LOW_SPEED |
+                                 USB_PORT_STAT_HIGH_SPEED |
+                                 USB_PORT_STAT_SUSPEND);
+                       break;
+               case USB_SPEED_LOW:
+                       info->ports[port].status |= USB_PORT_STAT_CONNECTION;
+                       info->ports[port].status |= USB_PORT_STAT_LOW_SPEED;
+                       break;
+               case USB_SPEED_FULL:
+                       info->ports[port].status |= USB_PORT_STAT_CONNECTION;
+                       break;
+               case USB_SPEED_HIGH:
+                       info->ports[port].status |= USB_PORT_STAT_CONNECTION;
+                       info->ports[port].status |= USB_PORT_STAT_HIGH_SPEED;
+                       break;
+               default: /* error */
+                       return;
+               }
+               info->ports[port].status |= (USB_PORT_STAT_C_CONNECTION << 16);
+       }
+}
+
+/*
+ * set virtual device connection status
+ */
+static void usbfront_rhport_connect(struct usbfront_info *info, int portnum,
+                                   enum usb_device_speed speed)
+{
+       int port;
+
+       if (portnum < 1 || portnum > info->rh_numports)
+               return; /* invalid port number */
+
+       port = portnum - 1;
+       if (info->devices[port].speed != speed) {
+               switch (speed) {
+               case USB_SPEED_UNKNOWN: /* disconnect */
+                       info->devices[port].status = USB_STATE_NOTATTACHED;
+                       break;
+               case USB_SPEED_LOW:
+               case USB_SPEED_FULL:
+               case USB_SPEED_HIGH:
+                       info->devices[port].status = USB_STATE_ATTACHED;
+                       break;
+               default: /* error */
+                       return;
+               }
+               info->devices[port].speed = speed;
+               info->ports[port].c_connection = 1;
+
+               usbfront_set_connect_state(info, portnum);
+       }
+}
+
+/*
+ * SetPortFeature(PORT_SUSPENDED)
+ */
+static void usbfront_rhport_suspend(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       info->ports[port].status |= USB_PORT_STAT_SUSPEND;
+       info->devices[port].status = USB_STATE_SUSPENDED;
+}
+
+/*
+ * ClearPortFeature(PORT_SUSPENDED)
+ */
+static void usbfront_rhport_resume(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       if (info->ports[port].status & USB_PORT_STAT_SUSPEND) {
+               info->ports[port].resuming = 1;
+               info->ports[port].timeout = jiffies + msecs_to_jiffies(20);
+       }
+}
+
+/*
+ * SetPortFeature(PORT_POWER)
+ */
+static void usbfront_rhport_power_on(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       if ((info->ports[port].status & USB_PORT_STAT_POWER) == 0) {
+               info->ports[port].status |= USB_PORT_STAT_POWER;
+               if (info->devices[port].status != USB_STATE_NOTATTACHED)
+                       info->devices[port].status = USB_STATE_POWERED;
+               if (info->ports[port].c_connection)
+                       usbfront_set_connect_state(info, portnum);
+       }
+}
+
+/*
+ * ClearPortFeature(PORT_POWER)
+ * SetConfiguration(non-zero)
+ * Power_Source_Off
+ * Over-current
+ */
+static void usbfront_rhport_power_off(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       if (info->ports[port].status & USB_PORT_STAT_POWER) {
+               info->ports[port].status = 0;
+               if (info->devices[port].status != USB_STATE_NOTATTACHED)
+                       info->devices[port].status = USB_STATE_ATTACHED;
+       }
+}
+
+/*
+ * ClearPortFeature(PORT_ENABLE)
+ */
+static void usbfront_rhport_disable(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       info->ports[port].status &= ~USB_PORT_STAT_ENABLE;
+       info->ports[port].status &= ~USB_PORT_STAT_SUSPEND;
+       info->ports[port].resuming = 0;
+       if (info->devices[port].status != USB_STATE_NOTATTACHED)
+               info->devices[port].status = USB_STATE_POWERED;
+}
+
+/*
+ * SetPortFeature(PORT_RESET)
+ */
+static void usbfront_rhport_reset(struct usbfront_info *info, int portnum)
+{
+       int port;
+
+       port = portnum - 1;
+       info->ports[port].status &= ~(USB_PORT_STAT_ENABLE |
+                                     USB_PORT_STAT_LOW_SPEED |
+                                     USB_PORT_STAT_HIGH_SPEED);
+       info->ports[port].status |= USB_PORT_STAT_RESET;
+
+       if (info->devices[port].status != USB_STATE_NOTATTACHED)
+               info->devices[port].status = USB_STATE_ATTACHED;
+
+       /* 10msec reset signaling */
+       info->ports[port].timeout = jiffies + msecs_to_jiffies(10);
+}
+
+#ifdef CONFIG_PM
+static int usbfront_hcd_bus_suspend(struct usb_hcd *hcd)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       int ret = 0;
+       int i, ports;
+
+       ports = info->rh_numports;
+
+       spin_lock_irq(&info->lock);
+       if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
+               ret = -ESHUTDOWN;
+       } else {
+               /* suspend any active ports*/
+               for (i = 1; i <= ports; i++)
+                       usbfront_rhport_suspend(info, i);
+       }
+       spin_unlock_irq(&info->lock);
+
+       del_timer_sync(&info->watchdog);
+
+       return ret;
+}
+
+static int usbfront_hcd_bus_resume(struct usb_hcd *hcd)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       int ret = 0;
+       int i, ports;
+
+       ports = info->rh_numports;
+
+       spin_lock_irq(&info->lock);
+       if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
+               ret = -ESHUTDOWN;
+       } else {
+               /* resume any suspended ports*/
+               for (i = 1; i <= ports; i++)
+                       usbfront_rhport_resume(info, i);
+       }
+       spin_unlock_irq(&info->lock);
+
+       return ret;
+}
+#endif
+
+static void usbfront_hcd_hub_descriptor(struct usbfront_info *info,
+                                       struct usb_hub_descriptor *desc)
+{
+       u16 temp;
+       int ports = info->rh_numports;
+
+       desc->bDescriptorType = 0x29;
+       desc->bPwrOn2PwrGood = 10; /* EHCI says 20ms max */
+       desc->bHubContrCurrent = 0;
+       desc->bNbrPorts = ports;
+
+       /* size of DeviceRemovable and PortPwrCtrlMask fields */
+       temp = 1 + (ports / 8);
+       desc->bDescLength = 7 + 2 * temp;
+
+       /* bitmaps for DeviceRemovable and PortPwrCtrlMask */
+       memset(&desc->u.hs.DeviceRemovable[0], 0, temp);
+       memset(&desc->u.hs.DeviceRemovable[temp], 0xff, temp);
+
+       /* per-port over current reporting and no power switching */
+       temp = 0x000a;
+       desc->wHubCharacteristics = cpu_to_le16(temp);
+}
+
+/* port status change mask for hub_status_data */
+#define PORT_C_MASK    ((USB_PORT_STAT_C_CONNECTION |          \
+                         USB_PORT_STAT_C_ENABLE |              \
+                         USB_PORT_STAT_C_SUSPEND |             \
+                         USB_PORT_STAT_C_OVERCURRENT |         \
+                         USB_PORT_STAT_C_RESET) << 16)
+
+/*
+ * See USB 2.0 Spec, 11.12.4 Hub and Port Status Change Bitmap.
+ * If port status changed, writes the bitmap to buf and return
+ * that length(number of bytes).
+ * If Nothing changed, return 0.
+ */
+static int usbfront_hcd_hub_status_data(struct usb_hcd *hcd, char *buf)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       int ports;
+       int i;
+       int length;
+       unsigned long flags;
+       int ret = 0;
+       int changed = 0;
+
+       if (!HC_IS_RUNNING(hcd->state))
+               return 0;
+
+       /* initialize the status to no-changes */
+       ports = info->rh_numports;
+       length = 1 + (ports / 8);
+       for (i = 0; i < length; i++) {
+               buf[i] = 0;
+               ret++;
+       }
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       for (i = 0; i < ports; i++) {
+               /* check status for each port */
+               if (info->ports[i].status & PORT_C_MASK) {
+                       if (i < 7)
+                               buf[0] |= 1 << (i + 1);
+                       else if (i < 15)
+                               buf[1] |= 1 << (i - 7);
+                       else if (i < 23)
+                               buf[2] |= 1 << (i - 15);
+                       else
+                               buf[3] |= 1 << (i - 23);
+                       changed = 1;
+               }
+       }
+
+       if (!changed)
+               ret = 0;
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       return ret;
+}
+
+static int usbfront_hcd_hub_control(struct usb_hcd *hcd, u16 typeReq,
+                               u16 wValue, u16 wIndex, char *buf, u16 wLength)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       int ports = info->rh_numports;
+       unsigned long flags;
+       int ret = 0;
+       int i;
+       int changed = 0;
+
+       spin_lock_irqsave(&info->lock, flags);
+       switch (typeReq) {
+       case ClearHubFeature:
+               /* ignore this request */
+               break;
+       case ClearPortFeature:
+               if (!wIndex || wIndex > ports)
+                       goto error;
+
+               switch (wValue) {
+               case USB_PORT_FEAT_SUSPEND:
+                       usbfront_rhport_resume(info, wIndex);
+                       break;
+               case USB_PORT_FEAT_POWER:
+                       usbfront_rhport_power_off(info, wIndex);
+                       break;
+               case USB_PORT_FEAT_ENABLE:
+                       usbfront_rhport_disable(info, wIndex);
+                       break;
+               case USB_PORT_FEAT_C_CONNECTION:
+                       info->ports[wIndex-1].c_connection = 0;
+                       /* falling through */
+               default:
+                       info->ports[wIndex-1].status &= ~(1 << wValue);
+                       break;
+               }
+               break;
+       case GetHubDescriptor:
+               usbfront_hcd_hub_descriptor(info,
+                                           (struct usb_hub_descriptor *)buf);
+               break;
+       case GetHubStatus:
+               /* always local power supply good and no over-current exists. */
+               *(__le32 *)buf = cpu_to_le32(0);
+               break;
+       case GetPortStatus:
+               if (!wIndex || wIndex > ports)
+                       goto error;
+
+               wIndex--;
+
+               /* resume completion */
+               if (info->ports[wIndex].resuming &&
+                   time_after_eq(jiffies, info->ports[wIndex].timeout)) {
+                       info->ports[wIndex].status |=
+                               USB_PORT_STAT_C_SUSPEND << 16;
+                       info->ports[wIndex].status &= ~USB_PORT_STAT_SUSPEND;
+               }
+
+               /* reset completion */
+               if ((info->ports[wIndex].status & USB_PORT_STAT_RESET) != 0 &&
+                   time_after_eq(jiffies, info->ports[wIndex].timeout)) {
+                       info->ports[wIndex].status |=
+                               USB_PORT_STAT_C_RESET << 16;
+                       info->ports[wIndex].status &= ~USB_PORT_STAT_RESET;
+
+                       if (info->devices[wIndex].status !=
+                           USB_STATE_NOTATTACHED) {
+                               info->ports[wIndex].status |=
+                                       USB_PORT_STAT_ENABLE;
+                               info->devices[wIndex].status =
+                                       USB_STATE_DEFAULT;
+                       }
+
+                       switch (info->devices[wIndex].speed) {
+                       case USB_SPEED_LOW:
+                               info->ports[wIndex].status |=
+                                       USB_PORT_STAT_LOW_SPEED;
+                               break;
+                       case USB_SPEED_HIGH:
+                               info->ports[wIndex].status |=
+                                       USB_PORT_STAT_HIGH_SPEED;
+                               break;
+                       default:
+                               break;
+                       }
+               }
+
+               ((u16 *)buf)[0] = cpu_to_le16(info->ports[wIndex].status);
+               ((u16 *)buf)[1] = cpu_to_le16(info->ports[wIndex].status >> 16);
+               break;
+       case SetPortFeature:
+               if (!wIndex || wIndex > ports)
+                       goto error;
+
+               switch (wValue) {
+               case USB_PORT_FEAT_POWER:
+                       usbfront_rhport_power_on(info, wIndex);
+                       break;
+               case USB_PORT_FEAT_RESET:
+                       usbfront_rhport_reset(info, wIndex);
+                       break;
+               case USB_PORT_FEAT_SUSPEND:
+                       usbfront_rhport_suspend(info, wIndex);
+                       break;
+               default:
+                       if (info->ports[wIndex-1].status & USB_PORT_STAT_POWER)
+                               info->ports[wIndex-1].status |= (1 << wValue);
+               }
+               break;
+
+       case SetHubFeature:
+               /* not supported */
+       default:
+error:
+               ret = -EPIPE;
+       }
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       /* check status for each port */
+       for (i = 0; i < ports; i++) {
+               if (info->ports[i].status & PORT_C_MASK)
+                       changed = 1;
+       }
+       if (changed)
+               usb_hcd_poll_rh_status(hcd);
+
+       return ret;
+}
+
+static void usbfront_free_urb_priv(struct urb_priv *urbp)
+{
+       urbp->urb->hcpriv = NULL;
+       kmem_cache_free(usbfront_urbp_cachep, urbp);
+}
+
+static inline int usbfront_get_id_from_freelist(struct usbfront_info *info)
+{
+       unsigned long free;
+
+       free = info->shadow_free;
+       BUG_ON(free >= USB_URB_RING_SIZE);
+       info->shadow_free = info->shadow[free].req.id;
+       info->shadow[free].req.id = (unsigned int)0x0fff; /* debug */
+       return free;
+}
+
+static inline void usbfront_add_id_to_freelist(struct usbfront_info *info,
+                                              unsigned long id)
+{
+       info->shadow[id].req.id = info->shadow_free;
+       info->shadow[id].urb = NULL;
+       info->shadow_free = id;
+}
+
+static inline int usbfront_count_pages(void *addr, int length)
+{
+       unsigned long vaddr = (unsigned long)addr;
+
+       return PFN_UP(vaddr + length) - PFN_DOWN(vaddr);
+}
+
+static void usbfront_hcd_gnttab_map(struct usbfront_info *info, void *addr,
+                                   int length, grant_ref_t *gref_head,
+                                   struct usbif_request_segment *seg,
+                                   int nr_pages, int flags)
+{
+       grant_ref_t ref;
+       unsigned long buffer_mfn;
+       unsigned int offset;
+       unsigned int len = length;
+       unsigned int bytes;
+       int i;
+
+       for (i = 0; i < nr_pages; i++) {
+               BUG_ON(!len);
+
+               buffer_mfn = PFN_DOWN(arbitrary_virt_to_machine(addr).maddr);
+               offset = offset_in_page(addr);
+
+               bytes = PAGE_SIZE - offset;
+               if (bytes > len)
+                       bytes = len;
+
+               ref = gnttab_claim_grant_reference(gref_head);
+               BUG_ON(ref == -ENOSPC);
+               gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
+                                               buffer_mfn, flags);
+               seg[i].gref = ref;
+               seg[i].offset = (uint16_t)offset;
+               seg[i].length = (uint16_t)bytes;
+
+               addr += bytes;
+               len -= bytes;
+       }
+}
+
+static int usbfront_map_urb_for_request(struct usbfront_info *info,
+                               struct urb *urb, struct usbif_urb_request *req)
+{
+       grant_ref_t gref_head;
+       int nr_buff_pages = 0;
+       int nr_isodesc_pages = 0;
+       int nr_grants = 0;
+
+       if (urb->transfer_buffer_length) {
+               nr_buff_pages = usbfront_count_pages(urb->transfer_buffer,
+                                               urb->transfer_buffer_length);
+
+               if (usb_pipeisoc(urb->pipe))
+                       nr_isodesc_pages = usbfront_count_pages(
+                               &urb->iso_frame_desc[0],
+                               sizeof(struct usb_iso_packet_descriptor) *
+                               urb->number_of_packets);
+
+               nr_grants = nr_buff_pages + nr_isodesc_pages;
+               if (nr_grants > USBIF_MAX_SEGMENTS_PER_REQUEST) {
+                       pr_err("usbfront: error: %d grants\n", nr_grants);
+                       return -E2BIG;
+               }
+
+               if (gnttab_alloc_grant_references(nr_grants, &gref_head)) {
+                       pr_err("usbfront: gnttab_alloc_grant_references() 
error\n");
+                       return -ENOMEM;
+               }
+
+               usbfront_hcd_gnttab_map(info, urb->transfer_buffer,
+                               urb->transfer_buffer_length, &gref_head,
+                               &req->seg[0], nr_buff_pages,
+                               usb_pipein(urb->pipe) ? 0 : GTF_readonly);
+       }
+
+       req->pipe = usbif_setportnum_pipe(urb->pipe, urb->dev->portnum);
+       req->transfer_flags = urb->transfer_flags;
+       req->buffer_length = urb->transfer_buffer_length;
+       req->nr_buffer_segs = nr_buff_pages;
+
+       switch (usb_pipetype(urb->pipe)) {
+       case PIPE_ISOCHRONOUS:
+               req->u.isoc.interval = urb->interval;
+               req->u.isoc.start_frame = urb->start_frame;
+               req->u.isoc.number_of_packets = urb->number_of_packets;
+               req->u.isoc.nr_frame_desc_segs = nr_isodesc_pages;
+
+               /* urb->number_of_packets must be > 0 */
+               BUG_ON(urb->number_of_packets <= 0);
+
+               usbfront_hcd_gnttab_map(info, &urb->iso_frame_desc[0],
+                               sizeof(struct usb_iso_packet_descriptor) *
+                               urb->number_of_packets,
+                               &gref_head, &req->seg[nr_buff_pages],
+                               nr_isodesc_pages, 0);
+               break;
+       case PIPE_INTERRUPT:
+               req->u.intr.interval = urb->interval;
+               break;
+       case PIPE_CONTROL:
+               if (urb->setup_packet)
+                       memcpy(req->u.ctrl, urb->setup_packet, 8);
+               break;
+       case PIPE_BULK:
+               break;
+       default:
+               BUG();
+       }
+
+       if (nr_grants)
+               gnttab_free_grant_references(gref_head);
+
+       return 0;
+}
+
+static void usbfront_hcd_gnttab_done(struct usb_shadow *shadow)
+{
+       int nr_segs = 0;
+       int i;
+
+       nr_segs = shadow->req.nr_buffer_segs;
+
+       if (usb_pipeisoc(shadow->req.pipe))
+               nr_segs += shadow->req.u.isoc.nr_frame_desc_segs;
+
+       for (i = 0; i < nr_segs; i++)
+               gnttab_end_foreign_access(shadow->req.seg[i].gref, 0, 0UL);
+
+       shadow->req.nr_buffer_segs = 0;
+       shadow->req.u.isoc.nr_frame_desc_segs = 0;
+}
+
+static void usbfront_hcd_giveback_urb(struct usbfront_info *info,
+                                     struct urb *urb, int status)
+{
+       struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
+       int priv_status = urbp->status;
+
+       list_del_init(&urbp->list);
+       usbfront_free_urb_priv(urbp);
+
+       if (urb->status == -EINPROGRESS)
+               urb->status = status;
+
+       spin_unlock(&info->lock);
+       usb_hcd_giveback_urb(usbfront_info_to_hcd(info), urb,
+                            priv_status <= 0 ? priv_status : urb->status);
+       spin_lock(&info->lock);
+}
+
+static int usbfront_hcd_do_request(struct usbfront_info *info,
+                                  struct urb_priv *urbp)
+{
+       struct usbif_urb_request *req;
+       struct urb *urb = urbp->urb;
+       uint16_t id;
+       int notify;
+       int ret;
+
+       req = RING_GET_REQUEST(&info->urb_ring, info->urb_ring.req_prod_pvt);
+       id = usbfront_get_id_from_freelist(info);
+       req->id = id;
+
+       if (unlikely(urbp->unlinked)) {
+               req->u.unlink.unlink_id = urbp->req_id;
+               req->pipe = usbif_setunlink_pipe(usbif_setportnum_pipe(
+                                       urb->pipe, urb->dev->portnum));
+               urbp->unlink_req_id = id;
+       } else {
+               ret = usbfront_map_urb_for_request(info, urb, req);
+               if (ret) {
+                       usbfront_add_id_to_freelist(info, id);
+                       return ret;
+               }
+               urbp->req_id = id;
+       }
+
+       info->urb_ring.req_prod_pvt++;
+       info->shadow[id].urb = urb;
+       info->shadow[id].req = *req;
+
+       RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->urb_ring, notify);
+       if (notify)
+               notify_remote_via_irq(info->irq);
+
+       return 0;
+}
+
+static void usbfront_hcd_kick_pending_urbs(struct usbfront_info *info)
+{
+       struct urb_priv *urbp;
+
+       while (!list_empty(&info->pending_submit_list)) {
+               if (RING_FULL(&info->urb_ring)) {
+                       usbfront_timer_action(info, TIMER_RING_WATCHDOG);
+                       return;
+               }
+
+               urbp = list_entry(info->pending_submit_list.next,
+                                 struct urb_priv, list);
+               if (!usbfront_hcd_do_request(info, urbp))
+                       list_move_tail(&urbp->list, &info->in_progress_list);
+               else
+                       usbfront_hcd_giveback_urb(info, urbp->urb, -ESHUTDOWN);
+       }
+       usbfront_timer_action_done(info, TIMER_SCAN_PENDING_URBS);
+}
+
+/*
+ * caller must lock info->lock
+ */
+static void usbfront_hcd_cancel_all_enqueued_urbs(struct usbfront_info *info)
+{
+       struct urb_priv *urbp, *tmp;
+       int req_id;
+
+       list_for_each_entry_safe(urbp, tmp, &info->in_progress_list, list) {
+               req_id = urbp->req_id;
+               if (!urbp->unlinked) {
+                       usbfront_hcd_gnttab_done(&info->shadow[req_id]);
+                       if (urbp->urb->status == -EINPROGRESS)
+                               /* not dequeued */
+                               usbfront_hcd_giveback_urb(info, urbp->urb,
+                                                         -ESHUTDOWN);
+                       else    /* dequeued */
+                               usbfront_hcd_giveback_urb(info, urbp->urb,
+                                                         urbp->urb->status);
+               }
+               info->shadow[req_id].urb = NULL;
+       }
+
+       list_for_each_entry_safe(urbp, tmp, &info->pending_submit_list, list)
+               usbfront_hcd_giveback_urb(info, urbp->urb, -ESHUTDOWN);
+}
+
+/*
+ * caller must lock info->lock
+ */
+static void usbfront_hcd_giveback_unlinked_urbs(struct usbfront_info *info)
+{
+       struct urb_priv *urbp, *tmp;
+
+       list_for_each_entry_safe(urbp, tmp, &info->giveback_waiting_list, list)
+               usbfront_hcd_giveback_urb(info, urbp->urb, urbp->urb->status);
+}
+
+static int usbfront_hcd_submit_urb(struct usbfront_info *info,
+                                  struct urb_priv *urbp)
+{
+       int ret;
+
+       if (RING_FULL(&info->urb_ring)) {
+               list_add_tail(&urbp->list, &info->pending_submit_list);
+               usbfront_timer_action(info, TIMER_RING_WATCHDOG);
+               return 0;
+       }
+
+       if (!list_empty(&info->pending_submit_list)) {
+               list_add_tail(&urbp->list, &info->pending_submit_list);
+               usbfront_timer_action(info, TIMER_SCAN_PENDING_URBS);
+               return 0;
+       }
+
+       ret = usbfront_hcd_do_request(info, urbp);
+       if (ret == 0)
+               list_add_tail(&urbp->list, &info->in_progress_list);
+
+       return ret;
+}
+
+static int usbfront_hcd_unlink_urb(struct usbfront_info *info,
+                                  struct urb_priv *urbp)
+{
+       int ret;
+
+       /* already unlinked? */
+       if (urbp->unlinked)
+               return -EBUSY;
+
+       urbp->unlinked = 1;
+
+       /* the urb is still in pending_submit queue */
+       if (urbp->req_id == ~0) {
+               list_move_tail(&urbp->list, &info->giveback_waiting_list);
+               usbfront_timer_action(info, TIMER_SCAN_PENDING_URBS);
+               return 0;
+       }
+
+       /* send unlink request to backend */
+       if (RING_FULL(&info->urb_ring)) {
+               list_move_tail(&urbp->list, &info->pending_unlink_list);
+               usbfront_timer_action(info, TIMER_RING_WATCHDOG);
+               return 0;
+       }
+
+       if (!list_empty(&info->pending_unlink_list)) {
+               list_move_tail(&urbp->list, &info->pending_unlink_list);
+               usbfront_timer_action(info, TIMER_SCAN_PENDING_URBS);
+               return 0;
+       }
+
+       ret = usbfront_hcd_do_request(info, urbp);
+       if (ret == 0)
+               list_move_tail(&urbp->list, &info->in_progress_list);
+
+       return ret;
+}
+
+static int usbfront_hcd_urb_request_done(struct usbfront_info *info)
+{
+       struct usbif_urb_response *res;
+       struct urb *urb;
+       RING_IDX i, rp;
+       uint16_t id;
+       int more_to_do = 0;
+       unsigned long flags;
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       rp = info->urb_ring.sring->rsp_prod;
+       rmb(); /* ensure we see queued responses up to "rp" */
+
+       for (i = info->urb_ring.rsp_cons; i != rp; i++) {
+               res = RING_GET_RESPONSE(&info->urb_ring, i);
+               id = res->id;
+
+               if (likely(usbif_pipesubmit(info->shadow[id].req.pipe))) {
+                       usbfront_hcd_gnttab_done(&info->shadow[id]);
+                       urb = info->shadow[id].urb;
+                       if (likely(urb)) {
+                               urb->actual_length = res->actual_length;
+                               urb->error_count = res->error_count;
+                               urb->start_frame = res->start_frame;
+                               usbfront_hcd_giveback_urb(info, urb,
+                                                         res->status);
+                       }
+               }
+
+               usbfront_add_id_to_freelist(info, id);
+       }
+       info->urb_ring.rsp_cons = i;
+
+       if (i != info->urb_ring.req_prod_pvt)
+               RING_FINAL_CHECK_FOR_RESPONSES(&info->urb_ring, more_to_do);
+       else
+               info->urb_ring.sring->rsp_event = i + 1;
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       return more_to_do;
+}
+
+static int usbfront_hcd_conn_notify(struct usbfront_info *info)
+{
+       struct usbif_conn_response *res;
+       struct usbif_conn_request *req;
+       RING_IDX rc, rp;
+       uint16_t id;
+       uint8_t portnum, speed;
+       int more_to_do = 0;
+       int notify;
+       int port_changed = 0;
+       unsigned long flags;
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       rc = info->conn_ring.rsp_cons;
+       rp = info->conn_ring.sring->rsp_prod;
+       rmb(); /* ensure we see queued responses up to "rp" */
+
+       while (rc != rp) {
+               res = RING_GET_RESPONSE(&info->conn_ring, rc);
+               id = res->id;
+               portnum = res->portnum;
+               speed = res->speed;
+               info->conn_ring.rsp_cons = ++rc;
+
+               usbfront_rhport_connect(info, portnum, speed);
+               if (info->ports[portnum - 1].c_connection)
+                       port_changed = 1;
+
+               barrier();
+
+               req = RING_GET_REQUEST(&info->conn_ring,
+                                      info->conn_ring.req_prod_pvt);
+               req->id = id;
+               info->conn_ring.req_prod_pvt++;
+       }
+
+       if (rc != info->conn_ring.req_prod_pvt)
+               RING_FINAL_CHECK_FOR_RESPONSES(&info->conn_ring, more_to_do);
+       else
+               info->conn_ring.sring->rsp_event = rc + 1;
+
+       RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->conn_ring, notify);
+       if (notify)
+               notify_remote_via_irq(info->irq);
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       if (port_changed)
+               usb_hcd_poll_rh_status(usbfront_info_to_hcd(info));
+
+       return more_to_do;
+}
+
+static irqreturn_t usbfront_hcd_int(int irq, void *dev_id)
+{
+       struct usbfront_info *info = (struct usbfront_info *)dev_id;
+
+       while (usbfront_hcd_urb_request_done(info) |
+              usbfront_hcd_conn_notify(info))
+               /* Yield point for this unbounded loop. */
+               cond_resched();
+
+       return IRQ_HANDLED;
+}
+
+static void usbfront_destroy_rings(struct usbfront_info *info)
+{
+       if (info->irq)
+               unbind_from_irqhandler(info->irq, info);
+       info->irq = 0;
+
+       if (info->urb_ring_ref != GRANT_INVALID_REF) {
+               gnttab_end_foreign_access(info->urb_ring_ref, 0,
+                                         (unsigned long)info->urb_ring.sring);
+               info->urb_ring_ref = GRANT_INVALID_REF;
+       }
+       info->urb_ring.sring = NULL;
+
+       if (info->conn_ring_ref != GRANT_INVALID_REF) {
+               gnttab_end_foreign_access(info->conn_ring_ref, 0,
+                                         (unsigned long)info->conn_ring.sring);
+               info->conn_ring_ref = GRANT_INVALID_REF;
+       }
+       info->conn_ring.sring = NULL;
+}
+
+static int usbfront_setup_rings(struct xenbus_device *dev,
+                               struct usbfront_info *info)
+{
+       struct usbif_urb_sring *urb_sring;
+       struct usbif_conn_sring *conn_sring;
+       int err;
+
+       info->urb_ring_ref = GRANT_INVALID_REF;
+       info->conn_ring_ref = GRANT_INVALID_REF;
+
+       urb_sring = (struct usbif_urb_sring *)get_zeroed_page(
+                                                       GFP_NOIO | __GFP_HIGH);
+       if (!urb_sring) {
+               xenbus_dev_fatal(dev, -ENOMEM, "allocating urb ring");
+               return -ENOMEM;
+       }
+       SHARED_RING_INIT(urb_sring);
+       FRONT_RING_INIT(&info->urb_ring, urb_sring, PAGE_SIZE);
+
+       err = xenbus_grant_ring(dev, virt_to_mfn(info->urb_ring.sring));
+       if (err < 0) {
+               free_page((unsigned long)urb_sring);
+               info->urb_ring.sring = NULL;
+               goto fail;
+       }
+       info->urb_ring_ref = err;
+
+       conn_sring = (struct usbif_conn_sring *)get_zeroed_page(
+                                                       GFP_NOIO | __GFP_HIGH);
+       if (!conn_sring) {
+               xenbus_dev_fatal(dev, -ENOMEM, "allocating conn ring");
+               err = -ENOMEM;
+               goto fail;
+       }
+       SHARED_RING_INIT(conn_sring);
+       FRONT_RING_INIT(&info->conn_ring, conn_sring, PAGE_SIZE);
+
+       err = xenbus_grant_ring(dev, virt_to_mfn(info->conn_ring.sring));
+       if (err < 0) {
+               free_page((unsigned long)conn_sring);
+               info->conn_ring.sring = NULL;
+               goto fail;
+       }
+       info->conn_ring_ref = err;
+
+       err = xenbus_alloc_evtchn(dev, &info->evtchn);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn");
+               goto fail;
+       }
+
+       err = bind_evtchn_to_irq(info->evtchn);
+       if (err <= 0) {
+               xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
+               goto fail;
+       }
+
+       info->irq = err;
+
+       err = request_threaded_irq(info->irq, NULL, usbfront_hcd_int,
+                                  IRQF_ONESHOT, "usbfront", info);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "request_threaded_irq");
+               goto free_irq;
+       }
+
+       return 0;
+
+free_irq:
+       unbind_from_irqhandler(info->irq, info);
+fail:
+       usbfront_destroy_rings(info);
+       return err;
+}
+
+static int usbfront_talk_to_backend(struct xenbus_device *dev,
+                                   struct usbfront_info *info)
+{
+       const char *message;
+       struct xenbus_transaction xbt;
+       int err;
+
+       err = usbfront_setup_rings(dev, info);
+       if (err)
+               return err;
+
+again:
+       err = xenbus_transaction_start(&xbt);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "starting transaction");
+               goto destroy_ring;
+       }
+
+       err = xenbus_printf(xbt, dev->nodename, "urb-ring-ref", "%u",
+                           info->urb_ring_ref);
+       if (err) {
+               message = "writing urb-ring-ref";
+               goto abort_transaction;
+       }
+
+       err = xenbus_printf(xbt, dev->nodename, "conn-ring-ref", "%u",
+                           info->conn_ring_ref);
+       if (err) {
+               message = "writing conn-ring-ref";
+               goto abort_transaction;
+       }
+
+       err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
+                           info->evtchn);
+       if (err) {
+               message = "writing event-channel";
+               goto abort_transaction;
+       }
+
+       err = xenbus_transaction_end(xbt, 0);
+       if (err) {
+               if (err == -EAGAIN)
+                       goto again;
+               xenbus_dev_fatal(dev, err, "completing transaction");
+               goto destroy_ring;
+       }
+
+       return 0;
+
+abort_transaction:
+       xenbus_transaction_end(xbt, 1);
+       xenbus_dev_fatal(dev, err, "%s", message);
+
+destroy_ring:
+       usbfront_destroy_rings(info);
+
+       return err;
+}
+
+static int usbfront_connect(struct xenbus_device *dev)
+{
+       struct usbfront_info *info = dev_get_drvdata(&dev->dev);
+       struct usbif_conn_request *req;
+       int idx, err;
+       int notify;
+       char name[TASK_COMM_LEN];
+       struct usb_hcd *hcd;
+
+       hcd = usbfront_info_to_hcd(info);
+       snprintf(name, TASK_COMM_LEN, "xenhcd.%d", hcd->self.busnum);
+
+       err = usbfront_talk_to_backend(dev, info);
+       if (err)
+               return err;
+
+       /* prepare ring for hotplug notification */
+       for (idx = 0; idx < USB_CONN_RING_SIZE; idx++) {
+               req = RING_GET_REQUEST(&info->conn_ring, idx);
+               req->id = idx;
+       }
+       info->conn_ring.req_prod_pvt = idx;
+
+       RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->conn_ring, notify);
+       if (notify)
+               notify_remote_via_irq(info->irq);
+
+       return 0;
+}
+
+static void usbfront_disconnect(struct xenbus_device *dev)
+{
+       struct usbfront_info *info = dev_get_drvdata(&dev->dev);
+       struct usb_hcd *hcd = usbfront_info_to_hcd(info);
+
+       usb_remove_hcd(hcd);
+       xenbus_frontend_closed(dev);
+}
+
+static void usbfront_hcd_watchdog(unsigned long param)
+{
+       struct usbfront_info *info = (struct usbfront_info *)param;
+       unsigned long flags;
+
+       spin_lock_irqsave(&info->lock, flags);
+       if (likely(HC_IS_RUNNING(usbfront_info_to_hcd(info)->state))) {
+               usbfront_timer_action_done(info, TIMER_RING_WATCHDOG);
+               usbfront_hcd_giveback_unlinked_urbs(info);
+               usbfront_hcd_kick_pending_urbs(info);
+       }
+       spin_unlock_irqrestore(&info->lock, flags);
+}
+
+/*
+ * one-time HC init
+ */
+static int usbfront_hcd_setup(struct usb_hcd *hcd)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+
+       spin_lock_init(&info->lock);
+       INIT_LIST_HEAD(&info->pending_submit_list);
+       INIT_LIST_HEAD(&info->pending_unlink_list);
+       INIT_LIST_HEAD(&info->in_progress_list);
+       INIT_LIST_HEAD(&info->giveback_waiting_list);
+       init_timer(&info->watchdog);
+       info->watchdog.function = usbfront_hcd_watchdog;
+       info->watchdog.data = (unsigned long)info;
+
+       hcd->has_tt = (hcd->driver->flags & HCD_MASK) != HCD_USB11;
+
+       return 0;
+}
+
+/*
+ * start HC running
+ */
+static int usbfront_hcd_run(struct usb_hcd *hcd)
+{
+       hcd->uses_new_polling = 1;
+       clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
+       hcd->state = HC_STATE_RUNNING;
+       usbfront_create_debug_file(usbfront_hcd_to_info(hcd));
+       return 0;
+}
+
+/*
+ * stop running HC
+ */
+static void usbfront_hcd_stop(struct usb_hcd *hcd)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+
+       del_timer_sync(&info->watchdog);
+       usbfront_remove_debug_file(info);
+       spin_lock_irq(&info->lock);
+       /* cancel all urbs */
+       hcd->state = HC_STATE_HALT;
+       usbfront_hcd_cancel_all_enqueued_urbs(info);
+       usbfront_hcd_giveback_unlinked_urbs(info);
+       spin_unlock_irq(&info->lock);
+}
+
+/*
+ * called as .urb_enqueue()
+ * non-error returns are promise to giveback the urb later
+ */
+static int usbfront_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
+                                   gfp_t mem_flags)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       struct urb_priv *urbp;
+       unsigned long flags;
+       int ret;
+
+
+       urbp = kmem_cache_zalloc(usbfront_urbp_cachep, mem_flags);
+       if (!urbp)
+               return -ENOMEM;
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       urbp->urb = urb;
+       urb->hcpriv = urbp;
+       urbp->req_id = ~0;
+       urbp->unlink_req_id = ~0;
+       INIT_LIST_HEAD(&urbp->list);
+       urbp->status = 1;
+       urb->unlinked = 0;
+
+       ret = usbfront_hcd_submit_urb(info, urbp);
+
+       if (ret)
+               usbfront_free_urb_priv(urbp);
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       return ret;
+}
+
+/*
+ * called as .urb_dequeue()
+ */
+static int usbfront_hcd_urb_dequeue(struct usb_hcd *hcd, struct urb *urb,
+                                   int status)
+{
+       struct usbfront_info *info = usbfront_hcd_to_info(hcd);
+       struct urb_priv *urbp;
+       unsigned long flags;
+       int ret = 0;
+
+       spin_lock_irqsave(&info->lock, flags);
+
+       urbp = urb->hcpriv;
+       if (urbp) {
+               urbp->status = status;
+               ret = usbfront_hcd_unlink_urb(info, urbp);
+       }
+
+       spin_unlock_irqrestore(&info->lock, flags);
+
+       return ret;
+}
+
+/*
+ * called from usb_get_current_frame_number(),
+ * but, almost all drivers not use such function.
+ */
+static int usbfront_hcd_get_frame(struct usb_hcd *hcd)
+{
+       /* it means error, but probably no problem :-) */
+       return 0;
+}
+
+static const char usbfront_hcd_name[] = "xen_hcd";
+
+static struct hc_driver usbfront_usb20_hc_driver = {
+       .description = usbfront_hcd_name,
+       .product_desc = "Xen USB2.0 Virtual Host Controller",
+       .hcd_priv_size = sizeof(struct usbfront_info),
+       .flags = HCD_USB2,
+
+       /* basic HC lifecycle operations */
+       .reset = usbfront_hcd_setup,
+       .start = usbfront_hcd_run,
+       .stop = usbfront_hcd_stop,
+
+       /* managing urb I/O */
+       .urb_enqueue = usbfront_hcd_urb_enqueue,
+       .urb_dequeue = usbfront_hcd_urb_dequeue,
+       .get_frame_number = usbfront_hcd_get_frame,
+
+       /* root hub operations */
+       .hub_status_data = usbfront_hcd_hub_status_data,
+       .hub_control = usbfront_hcd_hub_control,
+#ifdef CONFIG_PM
+       .bus_suspend = usbfront_hcd_bus_suspend,
+       .bus_resume = usbfront_hcd_bus_resume,
+#endif
+};
+
+static struct hc_driver usbfront_usb11_hc_driver = {
+       .description = usbfront_hcd_name,
+       .product_desc = "Xen USB1.1 Virtual Host Controller",
+       .hcd_priv_size = sizeof(struct usbfront_info),
+       .flags = HCD_USB11,
+
+       /* basic HC lifecycle operations */
+       .reset = usbfront_hcd_setup,
+       .start = usbfront_hcd_run,
+       .stop = usbfront_hcd_stop,
+
+       /* managing urb I/O */
+       .urb_enqueue = usbfront_hcd_urb_enqueue,
+       .urb_dequeue = usbfront_hcd_urb_dequeue,
+       .get_frame_number = usbfront_hcd_get_frame,
+
+       /* root hub operations */
+       .hub_status_data = usbfront_hcd_hub_status_data,
+       .hub_control = usbfront_hcd_hub_control,
+#ifdef CONFIG_PM
+       .bus_suspend = usbfront_hcd_bus_suspend,
+       .bus_resume = usbfront_hcd_bus_resume,
+#endif
+};
+
+static struct usb_hcd *usbfront_create_hcd(struct xenbus_device *dev)
+{
+       int i;
+       int err = 0;
+       int num_ports;
+       int usb_ver;
+       struct usb_hcd *hcd = NULL;
+       struct usbfront_info *info;
+
+       err = xenbus_scanf(XBT_NIL, dev->otherend, "num-ports", "%d",
+                          &num_ports);
+       if (err != 1) {
+               xenbus_dev_fatal(dev, err, "reading num-ports");
+               return ERR_PTR(-EINVAL);
+       }
+       if (num_ports < 1 || num_ports > USB_MAXCHILDREN) {
+               xenbus_dev_fatal(dev, err, "invalid num-ports");
+               return ERR_PTR(-EINVAL);
+       }
+
+       err = xenbus_scanf(XBT_NIL, dev->otherend, "usb-ver", "%d", &usb_ver);
+       if (err != 1) {
+               xenbus_dev_fatal(dev, err, "reading usb-ver");
+               return ERR_PTR(-EINVAL);
+       }
+       switch (usb_ver) {
+       case USB_VER_USB11:
+               hcd = usb_create_hcd(&usbfront_usb11_hc_driver, &dev->dev,
+                                    dev_name(&dev->dev));
+               break;
+       case USB_VER_USB20:
+               hcd = usb_create_hcd(&usbfront_usb20_hc_driver, &dev->dev,
+                                    dev_name(&dev->dev));
+               break;
+       default:
+               xenbus_dev_fatal(dev, err, "invalid usb-ver");
+               return ERR_PTR(-EINVAL);
+       }
+       if (!hcd) {
+               xenbus_dev_fatal(dev, err,
+                                "fail to allocate USB host controller");
+               return ERR_PTR(-ENOMEM);
+       }
+
+       info = usbfront_hcd_to_info(hcd);
+       info->xbdev = dev;
+       info->rh_numports = num_ports;
+
+       for (i = 0; i < USB_URB_RING_SIZE; i++) {
+               info->shadow[i].req.id = i + 1;
+               info->shadow[i].urb = NULL;
+       }
+       info->shadow[USB_URB_RING_SIZE - 1].req.id = 0x0fff;
+
+       return hcd;
+}
+
+static void usbfront_backend_changed(struct xenbus_device *dev,
+                           enum xenbus_state backend_state)
+{
+       switch (backend_state) {
+       case XenbusStateInitialising:
+       case XenbusStateReconfiguring:
+       case XenbusStateReconfigured:
+       case XenbusStateUnknown:
+               break;
+
+       case XenbusStateInitWait:
+       case XenbusStateInitialised:
+       case XenbusStateConnected:
+               if (dev->state != XenbusStateInitialising)
+                       break;
+               if (!usbfront_connect(dev))
+                       xenbus_switch_state(dev, XenbusStateConnected);
+               break;
+
+       case XenbusStateClosed:
+               if (dev->state == XenbusStateClosed)
+                       break;
+               /* Missed the backend's Closing state -- fallthrough */
+       case XenbusStateClosing:
+               usbfront_disconnect(dev);
+               break;
+
+       default:
+               xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
+                                backend_state);
+               break;
+       }
+}
+
+static int usbfront_remove(struct xenbus_device *dev)
+{
+       struct usbfront_info *info = dev_get_drvdata(&dev->dev);
+       struct usb_hcd *hcd = usbfront_info_to_hcd(info);
+
+       usbfront_destroy_rings(info);
+       usb_put_hcd(hcd);
+
+       return 0;
+}
+
+static int usbfront_probe(struct xenbus_device *dev,
+                         const struct xenbus_device_id *id)
+{
+       int err;
+       struct usb_hcd *hcd;
+       struct usbfront_info *info;
+
+       if (usb_disabled())
+               return -ENODEV;
+
+       hcd = usbfront_create_hcd(dev);
+       if (IS_ERR(hcd)) {
+               err = PTR_ERR(hcd);
+               xenbus_dev_fatal(dev, err,
+                                "fail to create usb host controller");
+               return err;
+       }
+
+       info = usbfront_hcd_to_info(hcd);
+       dev_set_drvdata(&dev->dev, info);
+
+       err = usb_add_hcd(hcd, 0, 0);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "fail to add USB host controller");
+               usb_put_hcd(hcd);
+               dev_set_drvdata(&dev->dev, NULL);
+       }
+
+       return err;
+}
+
+static const struct xenbus_device_id usbfront_ids[] = {
+       { "vusb" },
+       { "" },
+};
+
+static struct xenbus_driver usbfront_driver = {
+       .ids                    = usbfront_ids,
+       .probe                  = usbfront_probe,
+       .otherend_changed       = usbfront_backend_changed,
+       .remove                 = usbfront_remove,
+};
+
+static int __init usbfront_init(void)
+{
+       if (!xen_domain())
+               return -ENODEV;
+
+       usbfront_urbp_cachep = kmem_cache_create("xenhcd_urb_priv",
+                                       sizeof(struct urb_priv), 0, 0, NULL);
+       if (!usbfront_urbp_cachep) {
+               pr_err("usbfront failed to create kmem cache\n");
+               return -ENOMEM;
+       }
+
+       return xenbus_register_frontend(&usbfront_driver);
+}
+module_init(usbfront_init);
+
+static void __exit usbfront_exit(void)
+{
+       kmem_cache_destroy(usbfront_urbp_cachep);
+       xenbus_unregister_driver(&usbfront_driver);
+}
+module_exit(usbfront_exit);
+
+MODULE_ALIAS("xen:vusb");
+MODULE_AUTHOR("Juergen Gross <jgross@xxxxxxxx>");
+MODULE_DESCRIPTION("Xen USB Virtual Host Controller driver (usbfront)");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
2.1.4


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