path: root/target/linux/goldfish/patches-2.6.30/0101-android_usb-Composite-USB-gadget-driver-for-android.patch

From 03e39e8f663c896dac11e87d96e8cb0292520e36 Mon Sep 17 00:00:00 2001
From: Mike Lockwood <lockwood@android.com>
Date: Tue, 2 Dec 2008 22:01:33 -0500
Subject: [PATCH 101/134] android_usb: Composite USB gadget driver for android.

Signed-off-by: Mike Lockwood <lockwood@android.com>

USB: android gadget: add remote wakeup attribute to android function

Add remote wakeup attribute to configuration descriptor of android
function to advertise remote wakeup capability to host

Acked-by: Allam, Suresh Reddy <sallam@qualcomm.com>

Signed-off-by: Mike Lockwood <lockwood@android.com>

usb gadget: link fixes for android composite gadget

Signed-off-by: Mike Lockwood <lockwood@android.com>

usb gadget: Fix null pointer errors in android composite driver

Signed-off-by: Mike Lockwood <lockwood@android.com>
---
 drivers/usb/gadget/Kconfig          |    8 +
 drivers/usb/gadget/Makefile         |    2 +
 drivers/usb/gadget/android.c        |  345 +++++
 drivers/usb/gadget/f_adb.c          |  668 ++++++++
 drivers/usb/gadget/f_adb.h          |   25 +
 drivers/usb/gadget/f_mass_storage.c | 2906 +++++++++++++++++++++++++++++++++++
 drivers/usb/gadget/f_mass_storage.h |   52 +
 include/linux/usb/android.h         |   40 +
 8 files changed, 4046 insertions(+), 0 deletions(-)
 create mode 100644 drivers/usb/gadget/android.c
 create mode 100644 drivers/usb/gadget/f_adb.c
 create mode 100644 drivers/usb/gadget/f_adb.h
 create mode 100644 drivers/usb/gadget/f_mass_storage.c
 create mode 100644 drivers/usb/gadget/f_mass_storage.h
 create mode 100644 include/linux/usb/android.h

--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -700,6 +700,14 @@ config USB_G_PRINTER
 	  For more information, see Documentation/usb/gadget_printer.txt
 	  which includes sample code for accessing the device file.
 
+config USB_ANDROID
+	tristate "Android Gadget"
+	help
+	  The Android gadget provides mass storage and adb transport.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_android".
+
 config USB_CDC_COMPOSITE
 	tristate "CDC Composite Device (Ethernet and ACM)"
 	depends on NET
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -33,6 +33,7 @@ gadgetfs-objs			:= inode.o
 g_file_storage-objs		:= file_storage.o
 g_printer-objs			:= printer.o
 g_cdc-objs			:= cdc2.o
+g_android-objs			:= android.o f_adb.o f_mass_storage.o
 
 obj-$(CONFIG_USB_ZERO)		+= g_zero.o
 obj-$(CONFIG_USB_ETH)		+= g_ether.o
@@ -42,4 +43,5 @@ obj-$(CONFIG_USB_G_SERIAL)	+= g_serial.o
 obj-$(CONFIG_USB_G_PRINTER)	+= g_printer.o
 obj-$(CONFIG_USB_MIDI_GADGET)	+= g_midi.o
 obj-$(CONFIG_USB_CDC_COMPOSITE) += g_cdc.o
+obj-$(CONFIG_USB_ANDROID)	+= g_android.o
 
--- /dev/null
+++ b/drivers/usb/gadget/android.c
@@ -0,0 +1,345 @@
+/*
+ * Gadget Driver for Android
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/* #define DEBUG */
+/* #define VERBOSE_DEBUG */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/utsname.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+
+#include <linux/usb/android.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+
+#include "f_mass_storage.h"
+#include "f_adb.h"
+
+#include "gadget_chips.h"
+
+/*
+ * Kbuild is not very cooperative with respect to linking separately
+ * compiled library objects into one module.  So for now we won't use
+ * separate compilation ... ensuring init/exit sections work to shrink
+ * the runtime footprint, and giving us at least some parts of what
+ * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
+ */
+#include "usbstring.c"
+#include "config.c"
+#include "epautoconf.c"
+#include "composite.c"
+
+MODULE_AUTHOR("Mike Lockwood");
+MODULE_DESCRIPTION("Android Composite USB Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");
+
+static const char longname[] = "Gadget Android";
+
+/* Default vendor and product IDs, overridden by platform data */
+#define VENDOR_ID		0x18D1
+#define PRODUCT_ID		0x0001
+#define ADB_PRODUCT_ID	0x0002
+
+struct android_dev {
+	struct usb_gadget *gadget;
+	struct usb_composite_dev *cdev;
+
+	int product_id;
+	int adb_product_id;
+	int version;
+
+	int adb_enabled;
+	int nluns;
+};
+
+static atomic_t adb_enable_excl;
+static struct android_dev *_android_dev;
+
+/* string IDs are assigned dynamically */
+
+#define STRING_MANUFACTURER_IDX		0
+#define STRING_PRODUCT_IDX		1
+#define STRING_SERIAL_IDX		2
+
+/* String Table */
+static struct usb_string strings_dev[] = {
+	/* These dummy values should be overridden by platform data */
+	[STRING_MANUFACTURER_IDX].s = "Android",
+	[STRING_PRODUCT_IDX].s = "Android",
+	[STRING_SERIAL_IDX].s = "0123456789ABCDEF",
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings stringtab_dev = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_dev,
+};
+
+static struct usb_gadget_strings *dev_strings[] = {
+	&stringtab_dev,
+	NULL,
+};
+
+static struct usb_device_descriptor device_desc = {
+	.bLength              = sizeof(device_desc),
+	.bDescriptorType      = USB_DT_DEVICE,
+	.bcdUSB               = __constant_cpu_to_le16(0x0200),
+	.bDeviceClass         = USB_CLASS_PER_INTERFACE,
+	.idVendor             = __constant_cpu_to_le16(VENDOR_ID),
+	.idProduct            = __constant_cpu_to_le16(PRODUCT_ID),
+	.bcdDevice            = __constant_cpu_to_le16(0xffff),
+	.bNumConfigurations   = 1,
+};
+
+static int __init android_bind_config(struct usb_configuration *c)
+{
+	struct android_dev *dev = _android_dev;
+	int ret;
+	printk(KERN_DEBUG "android_bind_config\n");
+
+	ret = mass_storage_function_add(dev->cdev, c, dev->nluns);
+	if (ret)
+		return ret;
+	return adb_function_add(dev->cdev, c);
+}
+
+static struct usb_configuration android_config_driver = {
+	.label		= "android",
+	.bind		= android_bind_config,
+	.bConfigurationValue = 1,
+	.bmAttributes	= USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
+	.bMaxPower	= 0x80, /* 250ma */
+};
+
+static int __init android_bind(struct usb_composite_dev *cdev)
+{
+	struct android_dev *dev = _android_dev;
+	struct usb_gadget	*gadget = cdev->gadget;
+	int			gcnum;
+	int			id;
+	int			ret;
+
+	printk(KERN_INFO "android_bind\n");
+
+	/* Allocate string descriptor numbers ... note that string
+	 * contents can be overridden by the composite_dev glue.
+	 */
+	id = usb_string_id(cdev);
+	if (id < 0)
+		return id;
+	strings_dev[STRING_MANUFACTURER_IDX].id = id;
+	device_desc.iManufacturer = id;
+
+	id = usb_string_id(cdev);
+	if (id < 0)
+		return id;
+	strings_dev[STRING_PRODUCT_IDX].id = id;
+	device_desc.iProduct = id;
+
+	id = usb_string_id(cdev);
+	if (id < 0)
+		return id;
+	strings_dev[STRING_SERIAL_IDX].id = id;
+	device_desc.iSerialNumber = id;
+
+	if (gadget->ops->wakeup)
+		android_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+
+	/* register our configuration */
+	ret = usb_add_config(cdev, &android_config_driver);
+	if (ret) {
+		printk(KERN_ERR "usb_add_config failed\n");
+		return ret;
+	}
+
+	gcnum = usb_gadget_controller_number(gadget);
+	if (gcnum >= 0)
+		device_desc.bcdDevice = cpu_to_le16(0x0200 + gcnum);
+	else {
+		/* gadget zero is so simple (for now, no altsettings) that
+		 * it SHOULD NOT have problems with bulk-capable hardware.
+		 * so just warn about unrcognized controllers -- don't panic.
+		 *
+		 * things like configuration and altsetting numbering
+		 * can need hardware-specific attention though.
+		 */
+		pr_warning("%s: controller '%s' not recognized\n",
+			longname, gadget->name);
+		device_desc.bcdDevice = __constant_cpu_to_le16(0x9999);
+	}
+
+	usb_gadget_set_selfpowered(gadget);
+	dev->cdev = cdev;
+
+	return 0;
+}
+
+static struct usb_composite_driver android_usb_driver = {
+	.name		= "android_usb",
+	.dev		= &device_desc,
+	.strings	= dev_strings,
+	.bind		= android_bind,
+};
+
+static void enable_adb(struct android_dev *dev, int enable)
+{
+	if (enable != dev->adb_enabled) {
+		dev->adb_enabled = enable;
+		adb_function_enable(enable);
+
+		/* set product ID to the appropriate value */
+		if (enable)
+			device_desc.idProduct =
+				__constant_cpu_to_le16(dev->adb_product_id);
+		else
+			device_desc.idProduct =
+				__constant_cpu_to_le16(dev->product_id);
+		if (dev->cdev)
+			dev->cdev->desc.idProduct = device_desc.idProduct;
+
+		/* force reenumeration */
+		if (dev->cdev && dev->cdev->gadget &&
+				dev->cdev->gadget->speed != USB_SPEED_UNKNOWN) {
+			usb_gadget_disconnect(dev->cdev->gadget);
+			msleep(10);
+			usb_gadget_connect(dev->cdev->gadget);
+		}
+	}
+}
+
+static int adb_enable_open(struct inode *ip, struct file *fp)
+{
+	if (atomic_inc_return(&adb_enable_excl) != 1) {
+		atomic_dec(&adb_enable_excl);
+		return -EBUSY;
+	}
+
+	printk(KERN_INFO "enabling adb\n");
+	enable_adb(_android_dev, 1);
+
+	return 0;
+}
+
+static int adb_enable_release(struct inode *ip, struct file *fp)
+{
+	printk(KERN_INFO "disabling adb\n");
+	enable_adb(_android_dev, 0);
+	atomic_dec(&adb_enable_excl);
+	return 0;
+}
+
+static struct file_operations adb_enable_fops = {
+	.owner =   THIS_MODULE,
+	.open =    adb_enable_open,
+	.release = adb_enable_release,
+};
+
+static struct miscdevice adb_enable_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "android_adb_enable",
+	.fops = &adb_enable_fops,
+};
+
+static int __init android_probe(struct platform_device *pdev)
+{
+	struct android_usb_platform_data *pdata = pdev->dev.platform_data;
+	struct android_dev *dev = _android_dev;
+
+	printk(KERN_INFO "android_probe pdata: %p\n", pdata);
+
+	if (pdata) {
+		if (pdata->vendor_id)
+			device_desc.idVendor =
+				__constant_cpu_to_le16(pdata->vendor_id);
+		if (pdata->product_id) {
+			dev->product_id = pdata->product_id;
+			device_desc.idProduct =
+				__constant_cpu_to_le16(pdata->product_id);
+		}
+		if (pdata->adb_product_id)
+			dev->adb_product_id = pdata->adb_product_id;
+		if (pdata->version)
+			dev->version = pdata->version;
+
+		if (pdata->product_name)
+			strings_dev[STRING_PRODUCT_IDX].s = pdata->product_name;
+		if (pdata->manufacturer_name)
+			strings_dev[STRING_MANUFACTURER_IDX].s =
+					pdata->manufacturer_name;
+		if (pdata->serial_number)
+			strings_dev[STRING_SERIAL_IDX].s = pdata->serial_number;
+		dev->nluns = pdata->nluns;
+	}
+
+	return 0;
+}
+
+static struct platform_driver android_platform_driver = {
+	.driver = { .name = "android_usb", },
+	.probe = android_probe,
+};
+
+static int __init init(void)
+{
+	struct android_dev *dev;
+	int ret;
+
+	printk(KERN_INFO "android init\n");
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	/* set default values, which should be overridden by platform data */
+	dev->product_id = PRODUCT_ID;
+	dev->adb_product_id = ADB_PRODUCT_ID;
+	_android_dev = dev;
+
+	ret = platform_driver_register(&android_platform_driver);
+	if (ret)
+		return ret;
+	ret = misc_register(&adb_enable_device);
+	if (ret) {
+		platform_driver_unregister(&android_platform_driver);
+		return ret;
+	}
+	ret = usb_composite_register(&android_usb_driver);
+	if (ret) {
+		misc_deregister(&adb_enable_device);
+		platform_driver_unregister(&android_platform_driver);
+	}
+	return ret;
+}
+module_init(init);
+
+static void __exit cleanup(void)
+{
+	usb_composite_unregister(&android_usb_driver);
+	misc_deregister(&adb_enable_device);
+	platform_driver_unregister(&android_platform_driver);
+	kfree(_android_dev);
+	_android_dev = NULL;
+}
+module_exit(cleanup);
--- /dev/null
+++ b/drivers/usb/gadget/f_adb.c
@@ -0,0 +1,668 @@
+/*
+ * Gadget Driver for Android ADB
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/* #define DEBUG */
+/* #define VERBOSE_DEBUG */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/delay.h>
+#include <linux/wait.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+
+#include "f_adb.h"
+
+#define BULK_BUFFER_SIZE           4096
+
+/* number of rx and tx requests to allocate */
+#define RX_REQ_MAX 4
+#define TX_REQ_MAX 4
+
+static const char shortname[] = "android_adb";
+
+struct adb_dev {
+	struct usb_function function;
+	struct usb_composite_dev *cdev;
+	spinlock_t lock;
+
+	struct usb_ep *ep_in;
+	struct usb_ep *ep_out;
+
+	int online;
+	int error;
+
+	atomic_t read_excl;
+	atomic_t write_excl;
+	atomic_t open_excl;
+
+	struct list_head tx_idle;
+	struct list_head rx_idle;
+	struct list_head rx_done;
+
+	wait_queue_head_t read_wq;
+	wait_queue_head_t write_wq;
+
+	/* the request we're currently reading from */
+	struct usb_request *read_req;
+	unsigned char *read_buf;
+	unsigned read_count;
+};
+
+static struct usb_interface_descriptor adb_interface_desc = {
+	.bLength                = USB_DT_INTERFACE_SIZE,
+	.bDescriptorType        = USB_DT_INTERFACE,
+	.bInterfaceNumber       = 0,
+	.bNumEndpoints          = 2,
+	.bInterfaceClass        = 0xFF,
+	.bInterfaceSubClass     = 0x42,
+	.bInterfaceProtocol     = 1,
+};
+
+static struct usb_endpoint_descriptor adb_highspeed_in_desc = {
+	.bLength                = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType        = USB_DT_ENDPOINT,
+	.bEndpointAddress       = USB_DIR_IN,
+	.bmAttributes           = USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor adb_highspeed_out_desc = {
+	.bLength                = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType        = USB_DT_ENDPOINT,
+	.bEndpointAddress       = USB_DIR_OUT,
+	.bmAttributes           = USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor adb_fullspeed_in_desc = {
+	.bLength                = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType        = USB_DT_ENDPOINT,
+	.bEndpointAddress       = USB_DIR_IN,
+	.bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor adb_fullspeed_out_desc = {
+	.bLength                = USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType        = USB_DT_ENDPOINT,
+	.bEndpointAddress       = USB_DIR_OUT,
+	.bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_adb_descs[] = {
+	(struct usb_descriptor_header *) &adb_interface_desc,
+	(struct usb_descriptor_header *) &adb_fullspeed_in_desc,
+	(struct usb_descriptor_header *) &adb_fullspeed_out_desc,
+	NULL,
+};
+
+static struct usb_descriptor_header *hs_adb_descs[] = {
+	(struct usb_descriptor_header *) &adb_interface_desc,
+	(struct usb_descriptor_header *) &adb_highspeed_in_desc,
+	(struct usb_descriptor_header *) &adb_highspeed_out_desc,
+	NULL,
+};
+
+/* used when adb function is disabled */
+static struct usb_descriptor_header *null_adb_descs[] = {
+	NULL,
+};
+
+
+/* temporary variable used between adb_open() and adb_gadget_bind() */
+static struct adb_dev *_adb_dev;
+
+static inline struct adb_dev *func_to_dev(struct usb_function *f)
+{
+	return container_of(f, struct adb_dev, function);
+}
+
+
+static struct usb_request *adb_request_new(struct usb_ep *ep, int buffer_size)
+{
+	struct usb_request *req = usb_ep_alloc_request(ep, GFP_KERNEL);
+	if (!req)
+		return NULL;
+
+	/* now allocate buffers for the requests */
+	req->buf = kmalloc(buffer_size, GFP_KERNEL);
+	if (!req->buf) {
+		usb_ep_free_request(ep, req);
+		return NULL;
+	}
+
+	return req;
+}
+
+static void adb_request_free(struct usb_request *req, struct usb_ep *ep)
+{
+	if (req) {
+		kfree(req->buf);
+		usb_ep_free_request(ep, req);
+	}
+}
+
+static inline int _lock(atomic_t *excl)
+{
+	if (atomic_inc_return(excl) == 1) {
+		return 0;
+	} else {
+		atomic_dec(excl);
+		return -1;
+	}
+}
+
+static inline void _unlock(atomic_t *excl)
+{
+	atomic_dec(excl);
+}
+
+/* add a request to the tail of a list */
+void req_put(struct adb_dev *dev, struct list_head *head,
+		struct usb_request *req)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	list_add_tail(&req->list, head);
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/* remove a request from the head of a list */
+struct usb_request *req_get(struct adb_dev *dev, struct list_head *head)
+{
+	unsigned long flags;
+	struct usb_request *req;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	if (list_empty(head)) {
+		req = 0;
+	} else {
+		req = list_first_entry(head, struct usb_request, list);
+		list_del(&req->list);
+	}
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return req;
+}
+
+static void adb_complete_in(struct usb_ep *ep, struct usb_request *req)
+{
+	struct adb_dev *dev = _adb_dev;
+
+	if (req->status != 0)
+		dev->error = 1;
+
+	req_put(dev, &dev->tx_idle, req);
+
+	wake_up(&dev->write_wq);
+}
+
+static void adb_complete_out(struct usb_ep *ep, struct usb_request *req)
+{
+	struct adb_dev *dev = _adb_dev;
+
+	if (req->status != 0) {
+		dev->error = 1;
+		req_put(dev, &dev->rx_idle, req);
+	} else {
+		req_put(dev, &dev->rx_done, req);
+	}
+
+	wake_up(&dev->read_wq);
+}
+
+static int __init create_bulk_endpoints(struct adb_dev *dev,
+				struct usb_endpoint_descriptor *in_desc,
+				struct usb_endpoint_descriptor *out_desc)
+{
+	struct usb_composite_dev *cdev = dev->cdev;
+	struct usb_request *req;
+	struct usb_ep *ep;
+	int i;
+
+	DBG(cdev, "create_bulk_endpoints dev: %p\n", dev);
+
+	ep = usb_ep_autoconfig(cdev->gadget, in_desc);
+	if (!ep) {
+		DBG(cdev, "usb_ep_autoconfig for ep_in failed\n");
+		return -ENODEV;
+	}
+	DBG(cdev, "usb_ep_autoconfig for ep_in got %s\n", ep->name);
+	dev->ep_in = ep;
+
+	ep = usb_ep_autoconfig(cdev->gadget, out_desc);
+	if (!ep) {
+		DBG(cdev, "usb_ep_autoconfig for ep_out failed\n");
+		return -ENODEV;
+	}
+	DBG(cdev, "usb_ep_autoconfig for adb ep_out got %s\n", ep->name);
+	dev->ep_out = ep;
+
+	/* now allocate requests for our endpoints */
+	for (i = 0; i < RX_REQ_MAX; i++) {
+		req = adb_request_new(dev->ep_out, BULK_BUFFER_SIZE);
+		if (!req)
+			goto fail;
+		req->complete = adb_complete_out;
+		req_put(dev, &dev->rx_idle, req);
+	}
+
+	for (i = 0; i < TX_REQ_MAX; i++) {
+		req = adb_request_new(dev->ep_in, BULK_BUFFER_SIZE);
+		if (!req)
+			goto fail;
+		req->complete = adb_complete_in;
+		req_put(dev, &dev->tx_idle, req);
+	}
+
+	return 0;
+
+fail:
+	printk(KERN_ERR "adb_bind() could not allocate requests\n");
+	return -1;
+}
+
+static ssize_t adb_read(struct file *fp, char __user *buf,
+				size_t count, loff_t *pos)
+{
+	struct adb_dev *dev = fp->private_data;
+	struct usb_composite_dev *cdev = dev->cdev;
+	struct usb_request *req;
+	int r = count, xfer;
+	int ret;
+
+	DBG(cdev, "adb_read(%d)\n", count);
+
+	if (_lock(&dev->read_excl))
+		return -EBUSY;
+
+	/* we will block until we're online */
+	while (!(dev->online || dev->error)) {
+		DBG(cdev, "adb_read: waiting for online state\n");
+		ret = wait_event_interruptible(dev->read_wq,
+				(dev->online || dev->error));
+		if (ret < 0) {
+			_unlock(&dev->read_excl);
+			return ret;
+		}
+	}
+
+	while (count > 0) {
+		if (dev->error) {
+			DBG(cdev, "adb_read dev->error\n");
+			r = -EIO;
+			break;
+		}
+
+		/* if we have idle read requests, get them queued */
+		while ((req = req_get(dev, &dev->rx_idle))) {
+requeue_req:
+			req->length = BULK_BUFFER_SIZE;
+			ret = usb_ep_queue(dev->ep_out, req, GFP_ATOMIC);
+
+			if (ret < 0) {
+				r = -EIO;
+				dev->error = 1;
+				req_put(dev, &dev->rx_idle, req);
+				goto fail;
+			} else {
+				DBG(cdev, "rx %p queue\n", req);
+			}
+		}
+
+		/* if we have data pending, give it to userspace */
+		if (dev->read_count > 0) {
+			if (dev->read_count < count)
+				xfer = dev->read_count;
+			else
+				xfer = count;
+
+			if (copy_to_user(buf, dev->read_buf, xfer)) {
+				r = -EFAULT;
+				break;
+			}
+			dev->read_buf += xfer;
+			dev->read_count -= xfer;
+			buf += xfer;
+			count -= xfer;
+
+			/* if we've emptied the buffer, release the request */
+			if (dev->read_count == 0) {
+				req_put(dev, &dev->rx_idle, dev->read_req);
+				dev->read_req = 0;
+			}
+			continue;
+		}
+
+		/* wait for a request to complete */
+		req = 0;
+		ret = wait_event_interruptible(dev->read_wq,
+			((req = req_get(dev, &dev->rx_done)) || dev->error));
+		if (req != 0) {
+			/* if we got a 0-len one we need to put it back into
+			** service.  if we made it the current read req we'd
+			** be stuck forever
+			*/
+			if (req->actual == 0)
+				goto requeue_req;
+
+			dev->read_req = req;
+			dev->read_count = req->actual;
+			dev->read_buf = req->buf;
+			DBG(cdev, "rx %p %d\n", req, req->actual);
+		}
+
+		if (ret < 0) {
+			r = ret;
+			break;
+		}
+	}
+
+fail:
+	_unlock(&dev->read_excl);
+	DBG(cdev, "adb_read returning %d\n", r);
+	return r;
+}
+
+static ssize_t adb_write(struct file *fp, const char __user *buf,
+				 size_t count, loff_t *pos)
+{
+	struct adb_dev *dev = fp->private_data;
+	struct usb_composite_dev *cdev = dev->cdev;
+	struct usb_request *req = 0;
+	int r = count, xfer;
+	int ret;
+
+	DBG(cdev, "adb_write(%d)\n", count);
+
+	if (_lock(&dev->write_excl))
+		return -EBUSY;
+
+	while (count > 0) {
+		if (dev->error) {
+			DBG(cdev, "adb_write dev->error\n");
+			r = -EIO;
+			break;
+		}
+
+		/* get an idle tx request to use */
+		req = 0;
+		ret = wait_event_interruptible(dev->write_wq,
+			((req = req_get(dev, &dev->tx_idle)) || dev->error));
+
+		if (ret < 0) {
+			r = ret;
+			break;
+		}
+
+		if (req != 0) {
+			if (count > BULK_BUFFER_SIZE)
+				xfer = BULK_BUFFER_SIZE;
+			else
+				xfer = count;
+			if (copy_from_user(req->buf, buf, xfer)) {
+				r = -EFAULT;
+				break;
+			}
+
+			req->length = xfer;
+			ret = usb_ep_queue(dev->ep_in, req, GFP_ATOMIC);
+			if (ret < 0) {
+				DBG(cdev, "adb_write: xfer error %d\n", ret);
+				dev->error = 1;
+				r = -EIO;
+				break;
+			}
+
+			buf += xfer;
+			count -= xfer;
+
+			/* zero this so we don't try to free it on error exit */
+			req = 0;
+		}
+	}
+
+	if (req)
+		req_put(dev, &dev->tx_idle, req);
+
+	_unlock(&dev->write_excl);
+	DBG(cdev, "adb_write returning %d\n", r);
+	return r;
+}
+
+static int adb_open(struct inode *ip, struct file *fp)
+{
+	printk(KERN_INFO "adb_open\n");
+	if (_lock(&_adb_dev->open_excl))
+		return -EBUSY;
+
+	fp->private_data = _adb_dev;
+
+	/* clear the error latch */
+	_adb_dev->error = 0;
+
+	return 0;
+}
+
+static int adb_release(struct inode *ip, struct file *fp)
+{
+	printk(KERN_INFO "adb_release\n");
+	_unlock(&_adb_dev->open_excl);
+	return 0;
+}
+
+/* file operations for ADB device /dev/android_adb */
+static struct file_operations adb_fops = {
+	.owner = THIS_MODULE,
+	.read = adb_read,
+	.write = adb_write,
+	.open = adb_open,
+	.release = adb_release,
+};
+
+static struct miscdevice adb_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = shortname,
+	.fops = &adb_fops,
+};
+
+static int __init
+adb_function_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct adb_dev	*dev = func_to_dev(f);
+	int			id;
+	int			ret;
+
+	dev->cdev = cdev;
+	DBG(cdev, "adb_function_bind dev: %p\n", dev);
+
+	/* allocate interface ID(s) */
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	adb_interface_desc.bInterfaceNumber = id;
+
+	/* allocate endpoints */
+	ret = create_bulk_endpoints(dev, &adb_fullspeed_in_desc,
+			&adb_fullspeed_out_desc);
+	if (ret)
+		return ret;
+
+	/* support high speed hardware */
+	if (gadget_is_dualspeed(c->cdev->gadget)) {
+		adb_highspeed_in_desc.bEndpointAddress =
+			adb_fullspeed_in_desc.bEndpointAddress;
+		adb_highspeed_out_desc.bEndpointAddress =
+			adb_fullspeed_out_desc.bEndpointAddress;
+	}
+
+	DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
+			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+			f->name, dev->ep_in->name, dev->ep_out->name);
+	return 0;
+}
+
+static void
+adb_function_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct adb_dev	*dev = func_to_dev(f);
+	struct usb_request *req;
+
+	spin_lock_irq(&dev->lock);
+
+	while ((req = req_get(dev, &dev->rx_idle)))
+		adb_request_free(req, dev->ep_out);
+	while ((req = req_get(dev, &dev->tx_idle)))
+		adb_request_free(req, dev->ep_in);
+
+	dev->online = 0;
+	dev->error = 1;
+	spin_unlock_irq(&dev->lock);
+
+	misc_deregister(&adb_device);
+	kfree(_adb_dev);
+	_adb_dev = NULL;
+}
+
+static int adb_function_set_alt(struct usb_function *f,
+		unsigned intf, unsigned alt)
+{
+	struct adb_dev	*dev = func_to_dev(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+	int ret;
+
+	DBG(cdev, "adb_function_set_alt intf: %d alt: %d\n", intf, alt);
+	ret = usb_ep_enable(dev->ep_in,
+			ep_choose(cdev->gadget,
+				&adb_highspeed_in_desc,
+				&adb_fullspeed_in_desc));
+	if (ret)
+		return ret;
+	ret = usb_ep_enable(dev->ep_out,
+			ep_choose(cdev->gadget,
+				&adb_highspeed_out_desc,
+				&adb_fullspeed_out_desc));
+	if (ret) {
+		usb_ep_disable(dev->ep_in);
+		return ret;
+	}
+	dev->online = 1;
+
+	/* readers may be blocked waiting for us to go online */
+	wake_up(&dev->read_wq);
+	return 0;
+}
+
+static void adb_function_disable(struct usb_function *f)
+{
+	struct adb_dev	*dev = func_to_dev(f);
+	struct usb_composite_dev	*cdev = dev->cdev;
+
+	DBG(cdev, "adb_function_disable\n");
+	dev->online = 0;
+	dev->error = 1;
+	usb_ep_disable(dev->ep_in);
+	usb_ep_disable(dev->ep_out);
+
+	/* readers may be blocked waiting for us to go online */
+	wake_up(&dev->read_wq);
+
+	VDBG(cdev, "%s disabled\n", dev->function.name);
+}
+
+int __init adb_function_add(struct usb_composite_dev *cdev,
+	struct usb_configuration *c)
+{
+	struct adb_dev *dev;
+	int ret;
+
+	printk(KERN_INFO "adb_function_add\n");
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	spin_lock_init(&dev->lock);
+
+	init_waitqueue_head(&dev->read_wq);
+	init_waitqueue_head(&dev->write_wq);
+
+	atomic_set(&dev->open_excl, 0);
+	atomic_set(&dev->read_excl, 0);
+	atomic_set(&dev->write_excl, 0);
+
+	INIT_LIST_HEAD(&dev->rx_idle);
+	INIT_LIST_HEAD(&dev->rx_done);
+	INIT_LIST_HEAD(&dev->tx_idle);
+
+	dev->cdev = cdev;
+	dev->function.name = "adb";
+	dev->function.descriptors = null_adb_descs;
+	dev->function.hs_descriptors = null_adb_descs;
+	dev->function.bind = adb_function_bind;
+	dev->function.unbind = adb_function_unbind;
+	dev->function.set_alt = adb_function_set_alt;
+	dev->function.disable = adb_function_disable;
+
+	/* _adb_dev must be set before calling usb_gadget_register_driver */
+	_adb_dev = dev;
+
+	ret = misc_register(&adb_device);
+	if (ret)
+		goto err1;
+	ret = usb_add_function(c, &dev->function);
+	if (ret)
+		goto err2;
+
+	return 0;
+
+err2:
+	misc_deregister(&adb_device);
+err1:
+	kfree(dev);
+	printk(KERN_ERR "adb gadget driver failed to initialize\n");
+	return ret;
+}
+
+void adb_function_enable(int enable)
+{
+	struct adb_dev *dev = _adb_dev;
+
+	if (dev) {
+		DBG(dev->cdev, "adb_function_enable(%s)\n",
+			enable ? "true" : "false");
+
+		if (enable) {
+			dev->function.descriptors = fs_adb_descs;
+			dev->function.hs_descriptors = hs_adb_descs;
+		} else {
+			dev->function.descriptors = null_adb_descs;
+			dev->function.hs_descriptors = null_adb_descs;
+		}
+	}
+}
+
--- /dev/null
+++ b/drivers/usb/gadget/f_adb.h
@@ -0,0 +1,25 @@
+/*
+ * Gadget Driver for Android ADB
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#ifndef __F_ADB_H
+#define __F_ADB_H
+
+int adb_function_add(struct usb_composite_dev *cdev,
+	struct usb_configuration *c);
+void adb_function_enable(int enable);
+
+#endif /* __F_ADB_H */
--- /dev/null
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -0,0 +1,2906 @@
+/*
+ * drivers/usb/gadget/f_mass_storage.c
+ *
+ * Function Driver for USB Mass Storage
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * Based heavily on the file_storage gadget driver in
+ * drivers/usb/gadget/file_storage.c and licensed under the same terms:
+ *
+ * Copyright (C) 2003-2007 Alan Stern
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* #define DEBUG */
+/* #define VERBOSE_DEBUG */
+/* #define DUMP_MSGS */
+
+
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/dcache.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/kref.h>
+#include <linux/kthread.h>
+#include <linux/limits.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/switch.h>
+#include <linux/freezer.h>
+#include <linux/utsname.h>
+#include <linux/wakelock.h>
+
+#include <linux/usb_usual.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+
+#include "f_mass_storage.h"
+#include "gadget_chips.h"
+
+
+#define BULK_BUFFER_SIZE           4096
+
+/*-------------------------------------------------------------------------*/
+
+#define DRIVER_NAME		"usb_mass_storage"
+#define MAX_LUNS		8
+
+static const char shortname[] = DRIVER_NAME;
+
+#ifdef DEBUG
+#define LDBG(lun, fmt, args...) \
+	dev_dbg(&(lun)->dev , fmt , ## args)
+#define MDBG(fmt,args...) \
+	printk(KERN_DEBUG DRIVER_NAME ": " fmt , ## args)
+#else
+#define LDBG(lun, fmt, args...) \
+	do { } while (0)
+#define MDBG(fmt,args...) \
+	do { } while (0)
+#undef VERBOSE_DEBUG
+#undef DUMP_MSGS
+#endif /* DEBUG */
+
+#ifdef VERBOSE_DEBUG
+#define VLDBG	LDBG
+#else
+#define VLDBG(lun, fmt, args...) \
+	do { } while (0)
+#endif /* VERBOSE_DEBUG */
+
+#define LERROR(lun, fmt, args...) \
+	dev_err(&(lun)->dev , fmt , ## args)
+#define LWARN(lun, fmt, args...) \
+	dev_warn(&(lun)->dev , fmt , ## args)
+#define LINFO(lun, fmt, args...) \
+	dev_info(&(lun)->dev , fmt , ## args)
+
+#define MINFO(fmt,args...) \
+	printk(KERN_INFO DRIVER_NAME ": " fmt , ## args)
+
+#undef DBG
+#undef VDBG
+#undef ERROR
+#undef WARNING
+#undef INFO
+#define DBG(d, fmt, args...) \
+	dev_dbg(&(d)->cdev->gadget->dev , fmt , ## args)
+#define VDBG(d, fmt, args...) \
+	dev_vdbg(&(d)->cdev->gadget->dev , fmt , ## args)
+#define ERROR(d, fmt, args...) \
+	dev_err(&(d)->cdev->gadget->dev , fmt , ## args)
+#define WARNING(d, fmt, args...) \
+	dev_warn(&(d)->cdev->gadget->dev , fmt , ## args)
+#define INFO(d, fmt, args...) \
+	dev_info(&(d)->cdev->gadget->dev , fmt , ## args)
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Bulk-only data structures */
+
+/* Command Block Wrapper */
+struct bulk_cb_wrap {
+	__le32	Signature;		/* Contains 'USBC' */
+	u32	Tag;			/* Unique per command id */
+	__le32	DataTransferLength;	/* Size of the data */
+	u8	Flags;			/* Direction in bit 7 */
+	u8	Lun;			/* LUN (normally 0) */
+	u8	Length;			/* Of the CDB, <= MAX_COMMAND_SIZE */
+	u8	CDB[16];		/* Command Data Block */
+};
+
+#define USB_BULK_CB_WRAP_LEN	31
+#define USB_BULK_CB_SIG		0x43425355	/* Spells out USBC */
+#define USB_BULK_IN_FLAG	0x80
+
+/* Command Status Wrapper */
+struct bulk_cs_wrap {
+	__le32	Signature;		/* Should = 'USBS' */
+	u32	Tag;			/* Same as original command */
+	__le32	Residue;		/* Amount not transferred */
+	u8	Status;			/* See below */
+};
+
+#define USB_BULK_CS_WRAP_LEN	13
+#define USB_BULK_CS_SIG		0x53425355	/* Spells out 'USBS' */
+#define USB_STATUS_PASS		0
+#define USB_STATUS_FAIL		1
+#define USB_STATUS_PHASE_ERROR	2
+
+/* Bulk-only class specific requests */
+#define USB_BULK_RESET_REQUEST		0xff
+#define USB_BULK_GET_MAX_LUN_REQUEST	0xfe
+
+/* Length of a SCSI Command Data Block */
+#define MAX_COMMAND_SIZE	16
+
+/* SCSI commands that we recognize */
+#define SC_FORMAT_UNIT			0x04
+#define SC_INQUIRY			0x12
+#define SC_MODE_SELECT_6		0x15
+#define SC_MODE_SELECT_10		0x55
+#define SC_MODE_SENSE_6			0x1a
+#define SC_MODE_SENSE_10		0x5a
+#define SC_PREVENT_ALLOW_MEDIUM_REMOVAL	0x1e
+#define SC_READ_6			0x08
+#define SC_READ_10			0x28
+#define SC_READ_12			0xa8
+#define SC_READ_CAPACITY		0x25
+#define SC_READ_FORMAT_CAPACITIES	0x23
+#define SC_RELEASE			0x17
+#define SC_REQUEST_SENSE		0x03
+#define SC_RESERVE			0x16
+#define SC_SEND_DIAGNOSTIC		0x1d
+#define SC_START_STOP_UNIT		0x1b
+#define SC_SYNCHRONIZE_CACHE		0x35
+#define SC_TEST_UNIT_READY		0x00
+#define SC_VERIFY			0x2f
+#define SC_WRITE_6			0x0a
+#define SC_WRITE_10			0x2a
+#define SC_WRITE_12			0xaa
+
+/* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */
+#define SS_NO_SENSE				0
+#define SS_COMMUNICATION_FAILURE		0x040800
+#define SS_INVALID_COMMAND			0x052000
+#define SS_INVALID_FIELD_IN_CDB			0x052400
+#define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE	0x052100
+#define SS_LOGICAL_UNIT_NOT_SUPPORTED		0x052500
+#define SS_MEDIUM_NOT_PRESENT			0x023a00
+#define SS_MEDIUM_REMOVAL_PREVENTED		0x055302
+#define SS_NOT_READY_TO_READY_TRANSITION	0x062800
+#define SS_RESET_OCCURRED			0x062900
+#define SS_SAVING_PARAMETERS_NOT_SUPPORTED	0x053900
+#define SS_UNRECOVERED_READ_ERROR		0x031100
+#define SS_WRITE_ERROR				0x030c02
+#define SS_WRITE_PROTECTED			0x072700
+
+#define SK(x)		((u8) ((x) >> 16))	/* Sense Key byte, etc. */
+#define ASC(x)		((u8) ((x) >> 8))
+#define ASCQ(x)		((u8) (x))
+
+
+/*-------------------------------------------------------------------------*/
+
+struct lun {
+	struct file	*filp;
+	loff_t		file_length;
+	loff_t		num_sectors;
+
+	unsigned int	ro : 1;
+	unsigned int	prevent_medium_removal : 1;
+	unsigned int	registered : 1;
+	unsigned int	info_valid : 1;
+
+	u32		sense_data;
+	u32		sense_data_info;
+	u32		unit_attention_data;
+
+	struct device	dev;
+};
+
+#define backing_file_is_open(curlun)	((curlun)->filp != NULL)
+
+
+static struct lun *dev_to_lun(struct device *dev)
+{
+	return container_of(dev, struct lun, dev);
+}
+
+/* Big enough to hold our biggest descriptor */
+#define EP0_BUFSIZE	256
+#define DELAYED_STATUS	(EP0_BUFSIZE + 999)	/* An impossibly large value */
+
+/* Number of buffers we will use.  2 is enough for double-buffering */
+#define NUM_BUFFERS	2
+
+enum fsg_buffer_state {
+	BUF_STATE_EMPTY = 0,
+	BUF_STATE_FULL,
+	BUF_STATE_BUSY
+};
+
+struct fsg_buffhd {
+	void				*buf;
+	enum fsg_buffer_state		state;
+	struct fsg_buffhd		*next;
+
+	/* The NetChip 2280 is faster, and handles some protocol faults
+	 * better, if we don't submit any short bulk-out read requests.
+	 * So we will record the intended request length here. */
+	unsigned int			bulk_out_intended_length;
+
+	struct usb_request		*inreq;
+	int				inreq_busy;
+	struct usb_request		*outreq;
+	int				outreq_busy;
+};
+
+enum fsg_state {
+	/* This one isn't used anywhere */
+	FSG_STATE_COMMAND_PHASE = -10,
+
+	FSG_STATE_DATA_PHASE,
+	FSG_STATE_STATUS_PHASE,
+
+	FSG_STATE_IDLE = 0,
+	FSG_STATE_ABORT_BULK_OUT,
+	FSG_STATE_RESET,
+	FSG_STATE_CONFIG_CHANGE,
+	FSG_STATE_EXIT,
+	FSG_STATE_TERMINATED
+};
+
+enum data_direction {
+	DATA_DIR_UNKNOWN = 0,
+	DATA_DIR_FROM_HOST,
+	DATA_DIR_TO_HOST,
+	DATA_DIR_NONE
+};
+
+struct fsg_dev {
+	struct usb_function function;
+	struct usb_composite_dev *cdev;
+
+	/* lock protects: state and all the req_busy's */
+	spinlock_t		lock;
+
+	/* filesem protects: backing files in use */
+	struct rw_semaphore	filesem;
+
+	/* reference counting: wait until all LUNs are released */
+	struct kref		ref;
+
+	unsigned int		bulk_out_maxpacket;
+	enum fsg_state		state;		/* For exception handling */
+
+	u8			config, new_config;
+
+	unsigned int		running : 1;
+	unsigned int		bulk_in_enabled : 1;
+	unsigned int		bulk_out_enabled : 1;
+	unsigned int		phase_error : 1;
+	unsigned int		short_packet_received : 1;
+	unsigned int		bad_lun_okay : 1;
+
+	unsigned long		atomic_bitflags;
+#define REGISTERED		0
+#define CLEAR_BULK_HALTS	1
+#define SUSPENDED		2
+
+	struct usb_ep		*bulk_in;
+	struct usb_ep		*bulk_out;
+
+	struct fsg_buffhd	*next_buffhd_to_fill;
+	struct fsg_buffhd	*next_buffhd_to_drain;
+	struct fsg_buffhd	buffhds[NUM_BUFFERS];
+
+	int			thread_wakeup_needed;
+	struct completion	thread_notifier;
+	struct task_struct	*thread_task;
+
+	int			cmnd_size;
+	u8			cmnd[MAX_COMMAND_SIZE];
+	enum data_direction	data_dir;
+	u32			data_size;
+	u32			data_size_from_cmnd;
+	u32			tag;
+	unsigned int		lun;
+	u32			residue;
+	u32			usb_amount_left;
+
+	unsigned int		nluns;
+	struct lun		*luns;
+	struct lun		*curlun;
+
+	u32				buf_size;
+	const char		*vendor;
+	const char		*product;
+	int				release;
+
+	struct switch_dev sdev;
+
+	struct wake_lock wake_lock;
+};
+
+static inline struct fsg_dev *func_to_dev(struct usb_function *f)
+{
+	return container_of(f, struct fsg_dev, function);
+}
+
+static int exception_in_progress(struct fsg_dev *fsg)
+{
+	return (fsg->state > FSG_STATE_IDLE);
+}
+
+/* Make bulk-out requests be divisible by the maxpacket size */
+static void set_bulk_out_req_length(struct fsg_dev *fsg,
+		struct fsg_buffhd *bh, unsigned int length)
+{
+	unsigned int	rem;
+
+	bh->bulk_out_intended_length = length;
+	rem = length % fsg->bulk_out_maxpacket;
+	if (rem > 0)
+		length += fsg->bulk_out_maxpacket - rem;
+	bh->outreq->length = length;
+}
+
+static struct fsg_dev			*the_fsg;
+
+static void	close_backing_file(struct fsg_dev *fsg, struct lun *curlun);
+static void	close_all_backing_files(struct fsg_dev *fsg);
+
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef DUMP_MSGS
+
+static void dump_msg(struct fsg_dev *fsg, const char *label,
+		const u8 *buf, unsigned int length)
+{
+	if (length < 512) {
+		DBG(fsg, "%s, length %u:\n", label, length);
+		print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET,
+				16, 1, buf, length, 0);
+	}
+}
+
+static void dump_cdb(struct fsg_dev *fsg)
+{}
+
+#else
+
+static void dump_msg(struct fsg_dev *fsg, const char *label,
+		const u8 *buf, unsigned int length)
+{}
+
+#ifdef VERBOSE_DEBUG
+
+static void dump_cdb(struct fsg_dev *fsg)
+{
+	print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE,
+			16, 1, fsg->cmnd, fsg->cmnd_size, 0);
+}
+
+#else
+
+static void dump_cdb(struct fsg_dev *fsg)
+{}
+
+#endif /* VERBOSE_DEBUG */
+#endif /* DUMP_MSGS */
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Routines for unaligned data access */
+
+static u16 get_be16(u8 *buf)
+{
+	return ((u16) buf[0] << 8) | ((u16) buf[1]);
+}
+
+static u32 get_be32(u8 *buf)
+{
+	return ((u32) buf[0] << 24) | ((u32) buf[1] << 16) |
+			((u32) buf[2] << 8) | ((u32) buf[3]);
+}
+
+static void put_be16(u8 *buf, u16 val)
+{
+	buf[0] = val >> 8;
+	buf[1] = val;
+}
+
+static void put_be32(u8 *buf, u32 val)
+{
+	buf[0] = val >> 24;
+	buf[1] = val >> 16;
+	buf[2] = val >> 8;
+	buf[3] = val & 0xff;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * DESCRIPTORS ... most are static, but strings and (full) configuration
+ * descriptors are built on demand.  Also the (static) config and interface
+ * descriptors are adjusted during fsg_bind().
+ */
+
+/* There is only one interface. */
+
+static struct usb_interface_descriptor
+intf_desc = {
+	.bLength =		sizeof intf_desc,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bNumEndpoints =	2,		/* Adjusted during fsg_bind() */
+	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
+	.bInterfaceSubClass =	US_SC_SCSI,
+	.bInterfaceProtocol =	US_PR_BULK,
+};
+
+/* Three full-speed endpoint descriptors: bulk-in, bulk-out,
+ * and interrupt-in. */
+
+static struct usb_endpoint_descriptor
+fs_bulk_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	/* wMaxPacketSize set by autoconfiguration */
+};
+
+static struct usb_endpoint_descriptor
+fs_bulk_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	/* wMaxPacketSize set by autoconfiguration */
+};
+
+static struct usb_descriptor_header *fs_function[] = {
+	(struct usb_descriptor_header *) &intf_desc,
+	(struct usb_descriptor_header *) &fs_bulk_in_desc,
+	(struct usb_descriptor_header *) &fs_bulk_out_desc,
+	NULL,
+};
+#define FS_FUNCTION_PRE_EP_ENTRIES	2
+
+
+static struct usb_endpoint_descriptor
+hs_bulk_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor
+hs_bulk_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16(512),
+	.bInterval =		1,	/* NAK every 1 uframe */
+};
+
+
+static struct usb_descriptor_header *hs_function[] = {
+	(struct usb_descriptor_header *) &intf_desc,
+	(struct usb_descriptor_header *) &hs_bulk_in_desc,
+	(struct usb_descriptor_header *) &hs_bulk_out_desc,
+	NULL,
+};
+
+/* Maxpacket and other transfer characteristics vary by speed. */
+static struct usb_endpoint_descriptor *
+ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs,
+		struct usb_endpoint_descriptor *hs)
+{
+	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
+		return hs;
+	return fs;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* These routines may be called in process context or in_irq */
+
+/* Caller must hold fsg->lock */
+static void wakeup_thread(struct fsg_dev *fsg)
+{
+	/* Tell the main thread that something has happened */
+	fsg->thread_wakeup_needed = 1;
+	if (fsg->thread_task)
+		wake_up_process(fsg->thread_task);
+}
+
+
+static void raise_exception(struct fsg_dev *fsg, enum fsg_state new_state)
+{
+	unsigned long		flags;
+
+	DBG(fsg, "raise_exception %d\n", (int)new_state);
+	/* Do nothing if a higher-priority exception is already in progress.
+	 * If a lower-or-equal priority exception is in progress, preempt it
+	 * and notify the main thread by sending it a signal. */
+	spin_lock_irqsave(&fsg->lock, flags);
+	if (fsg->state <= new_state) {
+		fsg->state = new_state;
+		if (fsg->thread_task)
+			send_sig_info(SIGUSR1, SEND_SIG_FORCED,
+					fsg->thread_task);
+	}
+	spin_unlock_irqrestore(&fsg->lock, flags);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Bulk and interrupt endpoint completion handlers.
+ * These always run in_irq. */
+
+static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct fsg_dev		*fsg = ep->driver_data;
+	struct fsg_buffhd	*bh = req->context;
+
+	if (req->status || req->actual != req->length)
+		DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+				req->status, req->actual, req->length);
+
+	/* Hold the lock while we update the request and buffer states */
+	smp_wmb();
+	spin_lock(&fsg->lock);
+	bh->inreq_busy = 0;
+	bh->state = BUF_STATE_EMPTY;
+	wakeup_thread(fsg);
+	spin_unlock(&fsg->lock);
+}
+
+static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct fsg_dev		*fsg = ep->driver_data;
+	struct fsg_buffhd	*bh = req->context;
+
+	dump_msg(fsg, "bulk-out", req->buf, req->actual);
+	if (req->status || req->actual != bh->bulk_out_intended_length)
+		DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+				req->status, req->actual,
+				bh->bulk_out_intended_length);
+
+	/* Hold the lock while we update the request and buffer states */
+	smp_wmb();
+	spin_lock(&fsg->lock);
+	bh->outreq_busy = 0;
+	bh->state = BUF_STATE_FULL;
+	wakeup_thread(fsg);
+	spin_unlock(&fsg->lock);
+}
+
+static int fsg_function_setup(struct usb_function *f,
+					const struct usb_ctrlrequest *ctrl)
+{
+	struct fsg_dev	*fsg = func_to_dev(f);
+	struct usb_composite_dev *cdev = fsg->cdev;
+	int			value = -EOPNOTSUPP;
+	u16			w_index = le16_to_cpu(ctrl->wIndex);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+	u16			w_length = le16_to_cpu(ctrl->wLength);
+
+	DBG(fsg, "fsg_function_setup\n");
+	/* Handle Bulk-only class-specific requests */
+	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS) {
+	DBG(fsg, "USB_TYPE_CLASS\n");
+		switch (ctrl->bRequest) {
+		case USB_BULK_RESET_REQUEST:
+			if (ctrl->bRequestType != (USB_DIR_OUT |
+					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+				break;
+			if (w_index != 0 || w_value != 0) {
+				value = -EDOM;
+				break;
+			}
+
+			/* Raise an exception to stop the current operation
+			 * and reinitialize our state. */
+			DBG(fsg, "bulk reset request\n");
+			raise_exception(fsg, FSG_STATE_RESET);
+			value = DELAYED_STATUS;
+			break;
+
+		case USB_BULK_GET_MAX_LUN_REQUEST:
+			if (ctrl->bRequestType != (USB_DIR_IN |
+					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+				break;
+			if (w_index != 0 || w_value != 0) {
+				value = -EDOM;
+				break;
+			}
+			VDBG(fsg, "get max LUN\n");
+			*(u8 *)cdev->req->buf = fsg->nluns - 1;
+			value = 1;
+			break;
+		}
+	}
+
+	if (value == -EOPNOTSUPP)
+		VDBG(fsg,
+			"unknown class-specific control req "
+			"%02x.%02x v%04x i%04x l%u\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			le16_to_cpu(ctrl->wValue), w_index, w_length);
+	return value;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* All the following routines run in process context */
+
+
+/* Use this for bulk or interrupt transfers, not ep0 */
+static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
+		struct usb_request *req, int *pbusy,
+		enum fsg_buffer_state *state)
+{
+	int	rc;
+
+	DBG(fsg, "start_transfer req: %p, req->buf: %p\n", req, req->buf);
+	if (ep == fsg->bulk_in)
+		dump_msg(fsg, "bulk-in", req->buf, req->length);
+
+	spin_lock_irq(&fsg->lock);
+	*pbusy = 1;
+	*state = BUF_STATE_BUSY;
+	spin_unlock_irq(&fsg->lock);
+	rc = usb_ep_queue(ep, req, GFP_KERNEL);
+	if (rc != 0) {
+		*pbusy = 0;
+		*state = BUF_STATE_EMPTY;
+
+		/* We can't do much more than wait for a reset */
+
+		/* Note: currently the net2280 driver fails zero-length
+		 * submissions if DMA is enabled. */
+		if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
+						req->length == 0))
+			WARN(fsg, "error in submission: %s --> %d\n",
+				(ep == fsg->bulk_in ? "bulk-in" : "bulk-out"),
+				rc);
+	}
+}
+
+
+static int sleep_thread(struct fsg_dev *fsg)
+{
+	int	rc = 0;
+
+	/* Wait until a signal arrives or we are woken up */
+	for (;;) {
+		try_to_freeze();
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (signal_pending(current)) {
+			rc = -EINTR;
+			break;
+		}
+		if (fsg->thread_wakeup_needed)
+			break;
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+	fsg->thread_wakeup_needed = 0;
+	return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_read(struct fsg_dev *fsg)
+{
+	struct lun		*curlun = fsg->curlun;
+	u32			lba;
+	struct fsg_buffhd	*bh;
+	int			rc;
+	u32			amount_left;
+	loff_t			file_offset, file_offset_tmp;
+	unsigned int		amount;
+	unsigned int		partial_page;
+	ssize_t			nread;
+
+	/* Get the starting Logical Block Address and check that it's
+	 * not too big */
+	if (fsg->cmnd[0] == SC_READ_6)
+		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
+	else {
+		lba = get_be32(&fsg->cmnd[2]);
+
+		/* We allow DPO (Disable Page Out = don't save data in the
+		 * cache) and FUA (Force Unit Access = don't read from the
+		 * cache), but we don't implement them. */
+		if ((fsg->cmnd[1] & ~0x18) != 0) {
+			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+			return -EINVAL;
+		}
+	}
+	if (lba >= curlun->num_sectors) {
+		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+		return -EINVAL;
+	}
+	file_offset = ((loff_t) lba) << 9;
+
+	/* Carry out the file reads */
+	amount_left = fsg->data_size_from_cmnd;
+	if (unlikely(amount_left == 0))
+		return -EIO;		/* No default reply */
+
+	for (;;) {
+
+		/* Figure out how much we need to read:
+		 * Try to read the remaining amount.
+		 * But don't read more than the buffer size.
+		 * And don't try to read past the end of the file.
+		 * Finally, if we're not at a page boundary, don't read past
+		 *	the next page.
+		 * If this means reading 0 then we were asked to read past
+		 *	the end of file. */
+		amount = min((unsigned int) amount_left,
+				(unsigned int)fsg->buf_size);
+		amount = min((loff_t) amount,
+				curlun->file_length - file_offset);
+		partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
+		if (partial_page > 0)
+			amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
+					partial_page);
+
+		/* Wait for the next buffer to become available */
+		bh = fsg->next_buffhd_to_fill;
+		while (bh->state != BUF_STATE_EMPTY) {
+			rc = sleep_thread(fsg);
+			if (rc)
+				return rc;
+		}
+
+		/* If we were asked to read past the end of file,
+		 * end with an empty buffer. */
+		if (amount == 0) {
+			curlun->sense_data =
+					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+			curlun->sense_data_info = file_offset >> 9;
+			curlun->info_valid = 1;
+			bh->inreq->length = 0;
+			bh->state = BUF_STATE_FULL;
+			break;
+		}
+
+		/* Perform the read */
+		file_offset_tmp = file_offset;
+		nread = vfs_read(curlun->filp,
+				(char __user *) bh->buf,
+				amount, &file_offset_tmp);
+		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+				(unsigned long long) file_offset,
+				(int) nread);
+		if (signal_pending(current))
+			return -EINTR;
+
+		if (nread < 0) {
+			LDBG(curlun, "error in file read: %d\n",
+					(int) nread);
+			nread = 0;
+		} else if (nread < amount) {
+			LDBG(curlun, "partial file read: %d/%u\n",
+					(int) nread, amount);
+			nread -= (nread & 511);	/* Round down to a block */
+		}
+		file_offset  += nread;
+		amount_left  -= nread;
+		fsg->residue -= nread;
+		bh->inreq->length = nread;
+		bh->state = BUF_STATE_FULL;
+
+		/* If an error occurred, report it and its position */
+		if (nread < amount) {
+			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
+			curlun->sense_data_info = file_offset >> 9;
+			curlun->info_valid = 1;
+			break;
+		}
+
+		if (amount_left == 0)
+			break;		/* No more left to read */
+
+		/* Send this buffer and go read some more */
+		start_transfer(fsg, fsg->bulk_in, bh->inreq,
+				&bh->inreq_busy, &bh->state);
+		fsg->next_buffhd_to_fill = bh->next;
+	}
+
+	return -EIO;		/* No default reply */
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_write(struct fsg_dev *fsg)
+{
+	struct lun		*curlun = fsg->curlun;
+	u32			lba;
+	struct fsg_buffhd	*bh;
+	int			get_some_more;
+	u32			amount_left_to_req, amount_left_to_write;
+	loff_t			usb_offset, file_offset, file_offset_tmp;
+	unsigned int		amount;
+	unsigned int		partial_page;
+	ssize_t			nwritten;
+	int			rc;
+
+	if (curlun->ro) {
+		curlun->sense_data = SS_WRITE_PROTECTED;
+		return -EINVAL;
+	}
+	curlun->filp->f_flags &= ~O_SYNC;	/* Default is not to wait */
+
+	/* Get the starting Logical Block Address and check that it's
+	 * not too big */
+	if (fsg->cmnd[0] == SC_WRITE_6)
+		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
+	else {
+		lba = get_be32(&fsg->cmnd[2]);
+
+		/* We allow DPO (Disable Page Out = don't save data in the
+		 * cache) and FUA (Force Unit Access = write directly to the
+		 * medium).  We don't implement DPO; we implement FUA by
+		 * performing synchronous output. */
+		if ((fsg->cmnd[1] & ~0x18) != 0) {
+			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+			return -EINVAL;
+		}
+		if (fsg->cmnd[1] & 0x08)	/* FUA */
+			curlun->filp->f_flags |= O_SYNC;
+	}
+	if (lba >= curlun->num_sectors) {
+		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+		return -EINVAL;
+	}
+
+	/* Carry out the file writes */
+	get_some_more = 1;
+	file_offset = usb_offset = ((loff_t) lba) << 9;
+	amount_left_to_req = amount_left_to_write = fsg->data_size_from_cmnd;
+
+	while (amount_left_to_write > 0) {
+
+		/* Queue a request for more data from the host */
+		bh = fsg->next_buffhd_to_fill;
+		if (bh->state == BUF_STATE_EMPTY && get_some_more) {
+
+			/* Figure out how much we want to get:
+			 * Try to get the remaining amount.
+			 * But don't get more than the buffer size.
+			 * And don't try to go past the end of the file.
+			 * If we're not at a page boundary,
+			 *	don't go past the next page.
+			 * If this means getting 0, then we were asked
+			 *	to write past the end of file.
+			 * Finally, round down to a block boundary. */
+			amount = min(amount_left_to_req, (u32)fsg->buf_size);
+			amount = min((loff_t) amount, curlun->file_length -
+					usb_offset);
+			partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
+			if (partial_page > 0)
+				amount = min(amount,
+	(unsigned int) PAGE_CACHE_SIZE - partial_page);
+
+			if (amount == 0) {
+				get_some_more = 0;
+				curlun->sense_data =
+					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+				curlun->sense_data_info = usb_offset >> 9;
+				curlun->info_valid = 1;
+				continue;
+			}
+			amount -= (amount & 511);
+			if (amount == 0) {
+
+				/* Why were we were asked to transfer a
+				 * partial block? */
+				get_some_more = 0;
+				continue;
+			}
+
+			/* Get the next buffer */
+			usb_offset += amount;
+			fsg->usb_amount_left -= amount;
+			amount_left_to_req -= amount;
+			if (amount_left_to_req == 0)
+				get_some_more = 0;
+
+			/* amount is always divisible by 512, hence by
+			 * the bulk-out maxpacket size */
+			bh->outreq->length = bh->bulk_out_intended_length =
+					amount;
+			start_transfer(fsg, fsg->bulk_out, bh->outreq,
+					&bh->outreq_busy, &bh->state);
+			fsg->next_buffhd_to_fill = bh->next;
+			continue;
+		}
+
+		/* Write the received data to the backing file */
+		bh = fsg->next_buffhd_to_drain;
+		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
+			break;			/* We stopped early */
+		if (bh->state == BUF_STATE_FULL) {
+			smp_rmb();
+			fsg->next_buffhd_to_drain = bh->next;
+			bh->state = BUF_STATE_EMPTY;
+
+			/* Did something go wrong with the transfer? */
+			if (bh->outreq->status != 0) {
+				curlun->sense_data = SS_COMMUNICATION_FAILURE;
+				curlun->sense_data_info = file_offset >> 9;
+				curlun->info_valid = 1;
+				break;
+			}
+
+			amount = bh->outreq->actual;
+			if (curlun->file_length - file_offset < amount) {
+				LERROR(curlun,
+	"write %u @ %llu beyond end %llu\n",
+	amount, (unsigned long long) file_offset,
+	(unsigned long long) curlun->file_length);
+				amount = curlun->file_length - file_offset;
+			}
+
+			/* Perform the write */
+			file_offset_tmp = file_offset;
+			nwritten = vfs_write(curlun->filp,
+					(char __user *) bh->buf,
+					amount, &file_offset_tmp);
+			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
+					(unsigned long long) file_offset,
+					(int) nwritten);
+			if (signal_pending(current))
+				return -EINTR;		/* Interrupted! */
+
+			if (nwritten < 0) {
+				LDBG(curlun, "error in file write: %d\n",
+						(int) nwritten);
+				nwritten = 0;
+			} else if (nwritten < amount) {
+				LDBG(curlun, "partial file write: %d/%u\n",
+						(int) nwritten, amount);
+				nwritten -= (nwritten & 511);
+						/* Round down to a block */
+			}
+			file_offset += nwritten;
+			amount_left_to_write -= nwritten;
+			fsg->residue -= nwritten;
+
+			/* If an error occurred, report it and its position */
+			if (nwritten < amount) {
+				curlun->sense_data = SS_WRITE_ERROR;
+				curlun->sense_data_info = file_offset >> 9;
+				curlun->info_valid = 1;
+				break;
+			}
+
+			/* Did the host decide to stop early? */
+			if (bh->outreq->actual != bh->outreq->length) {
+				fsg->short_packet_received = 1;
+				break;
+			}
+			continue;
+		}
+
+		/* Wait for something to happen */
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+
+	return -EIO;		/* No default reply */
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Sync the file data, don't bother with the metadata.
+ * The caller must own fsg->filesem.
+ * This code was copied from fs/buffer.c:sys_fdatasync(). */
+static int fsync_sub(struct lun *curlun)
+{
+	struct file	*filp = curlun->filp;
+	struct inode	*inode;
+	int		rc, err;
+
+	if (curlun->ro || !filp)
+		return 0;
+	if (!filp->f_op->fsync)
+		return -EINVAL;
+
+	inode = filp->f_path.dentry->d_inode;
+	mutex_lock(&inode->i_mutex);
+	rc = filemap_fdatawrite(inode->i_mapping);
+	err = filp->f_op->fsync(filp, filp->f_path.dentry, 1);
+	if (!rc)
+		rc = err;
+	err = filemap_fdatawait(inode->i_mapping);
+	if (!rc)
+		rc = err;
+	mutex_unlock(&inode->i_mutex);
+	VLDBG(curlun, "fdatasync -> %d\n", rc);
+	return rc;
+}
+
+static void fsync_all(struct fsg_dev *fsg)
+{
+	int	i;
+
+	for (i = 0; i < fsg->nluns; ++i)
+		fsync_sub(&fsg->luns[i]);
+}
+
+static int do_synchronize_cache(struct fsg_dev *fsg)
+{
+	struct lun	*curlun = fsg->curlun;
+	int		rc;
+
+	/* We ignore the requested LBA and write out all file's
+	 * dirty data buffers. */
+	rc = fsync_sub(curlun);
+	if (rc)
+		curlun->sense_data = SS_WRITE_ERROR;
+	return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static void invalidate_sub(struct lun *curlun)
+{
+	struct file	*filp = curlun->filp;
+	struct inode	*inode = filp->f_path.dentry->d_inode;
+	unsigned long	rc;
+
+	rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
+	VLDBG(curlun, "invalidate_inode_pages -> %ld\n", rc);
+}
+
+static int do_verify(struct fsg_dev *fsg)
+{
+	struct lun		*curlun = fsg->curlun;
+	u32			lba;
+	u32			verification_length;
+	struct fsg_buffhd	*bh = fsg->next_buffhd_to_fill;
+	loff_t			file_offset, file_offset_tmp;
+	u32			amount_left;
+	unsigned int		amount;
+	ssize_t			nread;
+
+	/* Get the starting Logical Block Address and check that it's
+	 * not too big */
+	lba = get_be32(&fsg->cmnd[2]);
+	if (lba >= curlun->num_sectors) {
+		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+		return -EINVAL;
+	}
+
+	/* We allow DPO (Disable Page Out = don't save data in the
+	 * cache) but we don't implement it. */
+	if ((fsg->cmnd[1] & ~0x10) != 0) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	verification_length = get_be16(&fsg->cmnd[7]);
+	if (unlikely(verification_length == 0))
+		return -EIO;		/* No default reply */
+
+	/* Prepare to carry out the file verify */
+	amount_left = verification_length << 9;
+	file_offset = ((loff_t) lba) << 9;
+
+	/* Write out all the dirty buffers before invalidating them */
+	fsync_sub(curlun);
+	if (signal_pending(current))
+		return -EINTR;
+
+	invalidate_sub(curlun);
+	if (signal_pending(current))
+		return -EINTR;
+
+	/* Just try to read the requested blocks */
+	while (amount_left > 0) {
+
+		/* Figure out how much we need to read:
+		 * Try to read the remaining amount, but not more than
+		 * the buffer size.
+		 * And don't try to read past the end of the file.
+		 * If this means reading 0 then we were asked to read
+		 * past the end of file. */
+		amount = min((unsigned int) amount_left,
+				(unsigned int)fsg->buf_size);
+		amount = min((loff_t) amount,
+				curlun->file_length - file_offset);
+		if (amount == 0) {
+			curlun->sense_data =
+					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+			curlun->sense_data_info = file_offset >> 9;
+			curlun->info_valid = 1;
+			break;
+		}
+
+		/* Perform the read */
+		file_offset_tmp = file_offset;
+		nread = vfs_read(curlun->filp,
+				(char __user *) bh->buf,
+				amount, &file_offset_tmp);
+		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+				(unsigned long long) file_offset,
+				(int) nread);
+		if (signal_pending(current))
+			return -EINTR;
+
+		if (nread < 0) {
+			LDBG(curlun, "error in file verify: %d\n",
+					(int) nread);
+			nread = 0;
+		} else if (nread < amount) {
+			LDBG(curlun, "partial file verify: %d/%u\n",
+					(int) nread, amount);
+			nread -= (nread & 511);	/* Round down to a sector */
+		}
+		if (nread == 0) {
+			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
+			curlun->sense_data_info = file_offset >> 9;
+			curlun->info_valid = 1;
+			break;
+		}
+		file_offset += nread;
+		amount_left -= nread;
+	}
+	return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_inquiry(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	u8	*buf = (u8 *) bh->buf;
+
+	if (!fsg->curlun) {		/* Unsupported LUNs are okay */
+		fsg->bad_lun_okay = 1;
+		memset(buf, 0, 36);
+		buf[0] = 0x7f;		/* Unsupported, no device-type */
+		return 36;
+	}
+
+	memset(buf, 0, 8);	/* Non-removable, direct-access device */
+
+	buf[1] = 0x80;	/* set removable bit */
+	buf[2] = 2;		/* ANSI SCSI level 2 */
+	buf[3] = 2;		/* SCSI-2 INQUIRY data format */
+	buf[4] = 31;		/* Additional length */
+				/* No special options */
+	sprintf(buf + 8, "%-8s%-16s%04x", fsg->vendor,
+			fsg->product, fsg->release);
+	return 36;
+}
+
+
+static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	struct lun	*curlun = fsg->curlun;
+	u8		*buf = (u8 *) bh->buf;
+	u32		sd, sdinfo;
+	int		valid;
+
+	/*
+	 * From the SCSI-2 spec., section 7.9 (Unit attention condition):
+	 *
+	 * If a REQUEST SENSE command is received from an initiator
+	 * with a pending unit attention condition (before the target
+	 * generates the contingent allegiance condition), then the
+	 * target shall either:
+	 *   a) report any pending sense data and preserve the unit
+	 *	attention condition on the logical unit, or,
+	 *   b) report the unit attention condition, may discard any
+	 *	pending sense data, and clear the unit attention
+	 *	condition on the logical unit for that initiator.
+	 *
+	 * FSG normally uses option a); enable this code to use option b).
+	 */
+#if 0
+	if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
+		curlun->sense_data = curlun->unit_attention_data;
+		curlun->unit_attention_data = SS_NO_SENSE;
+	}
+#endif
+
+	if (!curlun) {		/* Unsupported LUNs are okay */
+		fsg->bad_lun_okay = 1;
+		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+		sdinfo = 0;
+		valid = 0;
+	} else {
+		sd = curlun->sense_data;
+		sdinfo = curlun->sense_data_info;
+		valid = curlun->info_valid << 7;
+		curlun->sense_data = SS_NO_SENSE;
+		curlun->sense_data_info = 0;
+		curlun->info_valid = 0;
+	}
+
+	memset(buf, 0, 18);
+	buf[0] = valid | 0x70;			/* Valid, current error */
+	buf[2] = SK(sd);
+	put_be32(&buf[3], sdinfo);		/* Sense information */
+	buf[7] = 18 - 8;			/* Additional sense length */
+	buf[12] = ASC(sd);
+	buf[13] = ASCQ(sd);
+	return 18;
+}
+
+
+static int do_read_capacity(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	struct lun	*curlun = fsg->curlun;
+	u32		lba = get_be32(&fsg->cmnd[2]);
+	int		pmi = fsg->cmnd[8];
+	u8		*buf = (u8 *) bh->buf;
+
+	/* Check the PMI and LBA fields */
+	if (pmi > 1 || (pmi == 0 && lba != 0)) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	put_be32(&buf[0], curlun->num_sectors - 1);	/* Max logical block */
+	put_be32(&buf[4], 512);				/* Block length */
+	return 8;
+}
+
+
+static int do_mode_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	struct lun	*curlun = fsg->curlun;
+	int		mscmnd = fsg->cmnd[0];
+	u8		*buf = (u8 *) bh->buf;
+	u8		*buf0 = buf;
+	int		pc, page_code;
+	int		changeable_values, all_pages;
+	int		valid_page = 0;
+	int		len, limit;
+
+	if ((fsg->cmnd[1] & ~0x08) != 0) {		/* Mask away DBD */
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+	pc = fsg->cmnd[2] >> 6;
+	page_code = fsg->cmnd[2] & 0x3f;
+	if (pc == 3) {
+		curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
+		return -EINVAL;
+	}
+	changeable_values = (pc == 1);
+	all_pages = (page_code == 0x3f);
+
+	/* Write the mode parameter header.  Fixed values are: default
+	 * medium type, no cache control (DPOFUA), and no block descriptors.
+	 * The only variable value is the WriteProtect bit.  We will fill in
+	 * the mode data length later. */
+	memset(buf, 0, 8);
+	if (mscmnd == SC_MODE_SENSE_6) {
+		buf[2] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
+		buf += 4;
+		limit = 255;
+	} else {			/* SC_MODE_SENSE_10 */
+		buf[3] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
+		buf += 8;
+		limit = 65535;
+	}
+
+	/* No block descriptors */
+
+	/* Disabled to workaround USB reset problems with a Vista host.
+	 */
+#if 0
+	/* The mode pages, in numerical order.  The only page we support
+	 * is the Caching page. */
+	if (page_code == 0x08 || all_pages) {
+		valid_page = 1;
+		buf[0] = 0x08;		/* Page code */
+		buf[1] = 10;		/* Page length */
+		memset(buf+2, 0, 10);	/* None of the fields are changeable */
+
+		if (!changeable_values) {
+			buf[2] = 0x04;	/* Write cache enable, */
+					/* Read cache not disabled */
+					/* No cache retention priorities */
+			put_be16(&buf[4], 0xffff);  /* Don't disable prefetch */
+					/* Minimum prefetch = 0 */
+			put_be16(&buf[8], 0xffff);  /* Maximum prefetch */
+			/* Maximum prefetch ceiling */
+			put_be16(&buf[10], 0xffff);
+		}
+		buf += 12;
+	}
+#else
+	valid_page = 1;
+#endif
+
+	/* Check that a valid page was requested and the mode data length
+	 * isn't too long. */
+	len = buf - buf0;
+	if (!valid_page || len > limit) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	/*  Store the mode data length */
+	if (mscmnd == SC_MODE_SENSE_6)
+		buf0[0] = len - 1;
+	else
+		put_be16(buf0, len - 2);
+	return len;
+}
+
+static int do_start_stop(struct fsg_dev *fsg)
+{
+	struct lun	*curlun = fsg->curlun;
+	int		loej, start;
+
+	/* int immed = fsg->cmnd[1] & 0x01; */
+	loej = fsg->cmnd[4] & 0x02;
+	start = fsg->cmnd[4] & 0x01;
+
+	if (loej) {
+		/* eject request from the host */
+		if (backing_file_is_open(curlun)) {
+			close_backing_file(fsg, curlun);
+			curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
+		}
+	}
+
+	return 0;
+}
+
+static int do_prevent_allow(struct fsg_dev *fsg)
+{
+	struct lun	*curlun = fsg->curlun;
+	int		prevent;
+
+	prevent = fsg->cmnd[4] & 0x01;
+	if ((fsg->cmnd[4] & ~0x01) != 0) {		/* Mask away Prevent */
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	if (curlun->prevent_medium_removal && !prevent)
+		fsync_sub(curlun);
+	curlun->prevent_medium_removal = prevent;
+	return 0;
+}
+
+
+static int do_read_format_capacities(struct fsg_dev *fsg,
+			struct fsg_buffhd *bh)
+{
+	struct lun	*curlun = fsg->curlun;
+	u8		*buf = (u8 *) bh->buf;
+
+	buf[0] = buf[1] = buf[2] = 0;
+	buf[3] = 8;	/* Only the Current/Maximum Capacity Descriptor */
+	buf += 4;
+
+	put_be32(&buf[0], curlun->num_sectors);	/* Number of blocks */
+	put_be32(&buf[4], 512);				/* Block length */
+	buf[4] = 0x02;					/* Current capacity */
+	return 12;
+}
+
+
+static int do_mode_select(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	struct lun	*curlun = fsg->curlun;
+
+	/* We don't support MODE SELECT */
+	curlun->sense_data = SS_INVALID_COMMAND;
+	return -EINVAL;
+}
+
+
+/*-------------------------------------------------------------------------*/
+#if 0
+static int write_zero(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh;
+	int			rc;
+
+	DBG(fsg, "write_zero\n");
+	/* Wait for the next buffer to become available */
+	bh = fsg->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+
+	bh->inreq->length = 0;
+	start_transfer(fsg, fsg->bulk_in, bh->inreq,
+			&bh->inreq_busy, &bh->state);
+
+	fsg->next_buffhd_to_fill = bh->next;
+	return 0;
+}
+#endif
+
+static int throw_away_data(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh;
+	u32			amount;
+	int			rc;
+
+	DBG(fsg, "throw_away_data\n");
+	while ((bh = fsg->next_buffhd_to_drain)->state != BUF_STATE_EMPTY ||
+			fsg->usb_amount_left > 0) {
+
+		/* Throw away the data in a filled buffer */
+		if (bh->state == BUF_STATE_FULL) {
+			smp_rmb();
+			bh->state = BUF_STATE_EMPTY;
+			fsg->next_buffhd_to_drain = bh->next;
+
+			/* A short packet or an error ends everything */
+			if (bh->outreq->actual != bh->outreq->length ||
+					bh->outreq->status != 0) {
+				raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+				return -EINTR;
+			}
+			continue;
+		}
+
+		/* Try to submit another request if we need one */
+		bh = fsg->next_buffhd_to_fill;
+		if (bh->state == BUF_STATE_EMPTY && fsg->usb_amount_left > 0) {
+			amount = min(fsg->usb_amount_left, (u32) fsg->buf_size);
+
+			/* amount is always divisible by 512, hence by
+			 * the bulk-out maxpacket size */
+			bh->outreq->length = bh->bulk_out_intended_length =
+					amount;
+			start_transfer(fsg, fsg->bulk_out, bh->outreq,
+					&bh->outreq_busy, &bh->state);
+			fsg->next_buffhd_to_fill = bh->next;
+			fsg->usb_amount_left -= amount;
+			continue;
+		}
+
+		/* Otherwise wait for something to happen */
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+	return 0;
+}
+
+
+static int finish_reply(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh = fsg->next_buffhd_to_fill;
+	int			rc = 0;
+
+	switch (fsg->data_dir) {
+	case DATA_DIR_NONE:
+		break;			/* Nothing to send */
+
+	case DATA_DIR_UNKNOWN:
+		rc = -EINVAL;
+		break;
+
+	/* All but the last buffer of data must have already been sent */
+	case DATA_DIR_TO_HOST:
+		if (fsg->data_size == 0)
+			;		/* Nothing to send */
+
+		/* If there's no residue, simply send the last buffer */
+		else if (fsg->residue == 0) {
+			start_transfer(fsg, fsg->bulk_in, bh->inreq,
+					&bh->inreq_busy, &bh->state);
+			fsg->next_buffhd_to_fill = bh->next;
+		} else {
+			start_transfer(fsg, fsg->bulk_in, bh->inreq,
+					&bh->inreq_busy, &bh->state);
+			fsg->next_buffhd_to_fill = bh->next;
+#if 0
+			/* this is unnecessary, and was causing problems with MacOS */
+			if (bh->inreq->length > 0)
+				write_zero(fsg);
+#endif
+		}
+		break;
+
+	/* We have processed all we want from the data the host has sent.
+	 * There may still be outstanding bulk-out requests. */
+	case DATA_DIR_FROM_HOST:
+		if (fsg->residue == 0)
+			;		/* Nothing to receive */
+
+		/* Did the host stop sending unexpectedly early? */
+		else if (fsg->short_packet_received) {
+			raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+			rc = -EINTR;
+		}
+
+		/* We haven't processed all the incoming data.  Even though
+		 * we may be allowed to stall, doing so would cause a race.
+		 * The controller may already have ACK'ed all the remaining
+		 * bulk-out packets, in which case the host wouldn't see a
+		 * STALL.  Not realizing the endpoint was halted, it wouldn't
+		 * clear the halt -- leading to problems later on. */
+#if 0
+		fsg_set_halt(fsg, fsg->bulk_out);
+		raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+		rc = -EINTR;
+#endif
+
+		/* We can't stall.  Read in the excess data and throw it
+		 * all away. */
+		else
+			rc = throw_away_data(fsg);
+		break;
+	}
+	return rc;
+}
+
+
+static int send_status(struct fsg_dev *fsg)
+{
+	struct lun		*curlun = fsg->curlun;
+	struct fsg_buffhd	*bh;
+	int			rc;
+	u8			status = USB_STATUS_PASS;
+	u32			sd, sdinfo = 0;
+	struct bulk_cs_wrap	*csw;
+
+	DBG(fsg, "send_status\n");
+	/* Wait for the next buffer to become available */
+	bh = fsg->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+
+	if (curlun) {
+		sd = curlun->sense_data;
+		sdinfo = curlun->sense_data_info;
+	} else if (fsg->bad_lun_okay)
+		sd = SS_NO_SENSE;
+	else
+		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+
+	if (fsg->phase_error) {
+		DBG(fsg, "sending phase-error status\n");
+		status = USB_STATUS_PHASE_ERROR;
+		sd = SS_INVALID_COMMAND;
+	} else if (sd != SS_NO_SENSE) {
+		DBG(fsg, "sending command-failure status\n");
+		status = USB_STATUS_FAIL;
+		VDBG(fsg, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
+				"  info x%x\n",
+				SK(sd), ASC(sd), ASCQ(sd), sdinfo);
+	}
+
+	csw = bh->buf;
+
+	/* Store and send the Bulk-only CSW */
+	csw->Signature = __constant_cpu_to_le32(USB_BULK_CS_SIG);
+	csw->Tag = fsg->tag;
+	csw->Residue = cpu_to_le32(fsg->residue);
+	csw->Status = status;
+
+	bh->inreq->length = USB_BULK_CS_WRAP_LEN;
+	start_transfer(fsg, fsg->bulk_in, bh->inreq,
+			&bh->inreq_busy, &bh->state);
+
+	fsg->next_buffhd_to_fill = bh->next;
+	return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Check whether the command is properly formed and whether its data size
+ * and direction agree with the values we already have. */
+static int check_command(struct fsg_dev *fsg, int cmnd_size,
+		enum data_direction data_dir, unsigned int mask,
+		int needs_medium, const char *name)
+{
+	int			i;
+	int			lun = fsg->cmnd[1] >> 5;
+	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
+	char			hdlen[20];
+	struct lun		*curlun;
+
+	hdlen[0] = 0;
+	if (fsg->data_dir != DATA_DIR_UNKNOWN)
+		sprintf(hdlen, ", H%c=%u", dirletter[(int) fsg->data_dir],
+				fsg->data_size);
+	VDBG(fsg, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
+			name, cmnd_size, dirletter[(int) data_dir],
+			fsg->data_size_from_cmnd, fsg->cmnd_size, hdlen);
+
+	/* We can't reply at all until we know the correct data direction
+	 * and size. */
+	if (fsg->data_size_from_cmnd == 0)
+		data_dir = DATA_DIR_NONE;
+	if (fsg->data_dir == DATA_DIR_UNKNOWN) {	/* CB or CBI */
+		fsg->data_dir = data_dir;
+		fsg->data_size = fsg->data_size_from_cmnd;
+
+	} else {					/* Bulk-only */
+		if (fsg->data_size < fsg->data_size_from_cmnd) {
+
+			/* Host data size < Device data size is a phase error.
+			 * Carry out the command, but only transfer as much
+			 * as we are allowed. */
+			DBG(fsg, "phase error 1\n");
+			fsg->data_size_from_cmnd = fsg->data_size;
+			fsg->phase_error = 1;
+		}
+	}
+	fsg->residue = fsg->usb_amount_left = fsg->data_size;
+
+	/* Conflicting data directions is a phase error */
+	if (fsg->data_dir != data_dir && fsg->data_size_from_cmnd > 0) {
+		fsg->phase_error = 1;
+		DBG(fsg, "phase error 2\n");
+		return -EINVAL;
+	}
+
+	/* Verify the length of the command itself */
+	if (cmnd_size != fsg->cmnd_size) {
+
+		/* Special case workaround: MS-Windows issues REQUEST SENSE
+		 * with cbw->Length == 12 (it should be 6). */
+		if (fsg->cmnd[0] == SC_REQUEST_SENSE && fsg->cmnd_size == 12)
+			cmnd_size = fsg->cmnd_size;
+		else {
+			fsg->phase_error = 1;
+			return -EINVAL;
+		}
+	}
+
+	/* Check that the LUN values are consistent */
+	if (fsg->lun != lun)
+		DBG(fsg, "using LUN %d from CBW, "
+				"not LUN %d from CDB\n",
+				fsg->lun, lun);
+
+	/* Check the LUN */
+	if (fsg->lun >= 0 && fsg->lun < fsg->nluns) {
+		fsg->curlun = curlun = &fsg->luns[fsg->lun];
+		if (fsg->cmnd[0] != SC_REQUEST_SENSE) {
+			curlun->sense_data = SS_NO_SENSE;
+			curlun->sense_data_info = 0;
+			curlun->info_valid = 0;
+		}
+	} else {
+		fsg->curlun = curlun = NULL;
+		fsg->bad_lun_okay = 0;
+
+		/* INQUIRY and REQUEST SENSE commands are explicitly allowed
+		 * to use unsupported LUNs; all others may not. */
+		if (fsg->cmnd[0] != SC_INQUIRY &&
+				fsg->cmnd[0] != SC_REQUEST_SENSE) {
+			DBG(fsg, "unsupported LUN %d\n", fsg->lun);
+			return -EINVAL;
+		}
+	}
+
+	/* If a unit attention condition exists, only INQUIRY and
+	 * REQUEST SENSE commands are allowed; anything else must fail. */
+	if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
+			fsg->cmnd[0] != SC_INQUIRY &&
+			fsg->cmnd[0] != SC_REQUEST_SENSE) {
+		curlun->sense_data = curlun->unit_attention_data;
+		curlun->unit_attention_data = SS_NO_SENSE;
+		return -EINVAL;
+	}
+
+	/* Check that only command bytes listed in the mask are non-zero */
+	fsg->cmnd[1] &= 0x1f;			/* Mask away the LUN */
+	for (i = 1; i < cmnd_size; ++i) {
+		if (fsg->cmnd[i] && !(mask & (1 << i))) {
+			if (curlun)
+				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+			DBG(fsg, "SS_INVALID_FIELD_IN_CDB\n");
+			return -EINVAL;
+		}
+	}
+
+	/* If the medium isn't mounted and the command needs to access
+	 * it, return an error. */
+	if (curlun && !backing_file_is_open(curlun) && needs_medium) {
+		curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
+		DBG(fsg, "SS_MEDIUM_NOT_PRESENT\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+static int do_scsi_command(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh;
+	int			rc;
+	int			reply = -EINVAL;
+	int			i;
+	static char		unknown[16];
+
+	dump_cdb(fsg);
+
+	/* Wait for the next buffer to become available for data or status */
+	bh = fsg->next_buffhd_to_drain = fsg->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+	fsg->phase_error = 0;
+	fsg->short_packet_received = 0;
+
+	down_read(&fsg->filesem);	/* We're using the backing file */
+	switch (fsg->cmnd[0]) {
+
+	case SC_INQUIRY:
+		fsg->data_size_from_cmnd = fsg->cmnd[4];
+		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+				(1<<4), 0,
+				"INQUIRY")) == 0)
+			reply = do_inquiry(fsg, bh);
+		break;
+
+	case SC_MODE_SELECT_6:
+		fsg->data_size_from_cmnd = fsg->cmnd[4];
+		if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
+				(1<<1) | (1<<4), 0,
+				"MODE SELECT(6)")) == 0)
+			reply = do_mode_select(fsg, bh);
+		break;
+
+	case SC_MODE_SELECT_10:
+		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
+		if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
+				(1<<1) | (3<<7), 0,
+				"MODE SELECT(10)")) == 0)
+			reply = do_mode_select(fsg, bh);
+		break;
+
+	case SC_MODE_SENSE_6:
+		fsg->data_size_from_cmnd = fsg->cmnd[4];
+		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+				(1<<1) | (1<<2) | (1<<4), 0,
+				"MODE SENSE(6)")) == 0)
+			reply = do_mode_sense(fsg, bh);
+		break;
+
+	case SC_MODE_SENSE_10:
+		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
+		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+				(1<<1) | (1<<2) | (3<<7), 0,
+				"MODE SENSE(10)")) == 0)
+			reply = do_mode_sense(fsg, bh);
+		break;
+
+	case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
+		fsg->data_size_from_cmnd = 0;
+		if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
+				(1<<4), 0,
+				"PREVENT-ALLOW MEDIUM REMOVAL")) == 0)
+			reply = do_prevent_allow(fsg);
+		break;
+
+	case SC_READ_6:
+		i = fsg->cmnd[4];
+		fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+				(7<<1) | (1<<4), 1,
+				"READ(6)")) == 0)
+			reply = do_read(fsg);
+		break;
+
+	case SC_READ_10:
+		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
+		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+				(1<<1) | (0xf<<2) | (3<<7), 1,
+				"READ(10)")) == 0)
+			reply = do_read(fsg);
+		break;
+
+	case SC_READ_12:
+		fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
+		if ((reply = check_command(fsg, 12, DATA_DIR_TO_HOST,
+				(1<<1) | (0xf<<2) | (0xf<<6), 1,
+				"READ(12)")) == 0)
+			reply = do_read(fsg);
+		break;
+
+	case SC_READ_CAPACITY:
+		fsg->data_size_from_cmnd = 8;
+		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+				(0xf<<2) | (1<<8), 1,
+				"READ CAPACITY")) == 0)
+			reply = do_read_capacity(fsg, bh);
+		break;
+
+	case SC_READ_FORMAT_CAPACITIES:
+		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]);
+		if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+				(3<<7), 1,
+				"READ FORMAT CAPACITIES")) == 0)
+			reply = do_read_format_capacities(fsg, bh);
+		break;
+
+	case SC_REQUEST_SENSE:
+		fsg->data_size_from_cmnd = fsg->cmnd[4];
+		if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+				(1<<4), 0,
+				"REQUEST SENSE")) == 0)
+			reply = do_request_sense(fsg, bh);
+		break;
+
+	case SC_START_STOP_UNIT:
+		fsg->data_size_from_cmnd = 0;
+		if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
+				(1<<1) | (1<<4), 0,
+				"START-STOP UNIT")) == 0)
+			reply = do_start_stop(fsg);
+		break;
+
+	case SC_SYNCHRONIZE_CACHE:
+		fsg->data_size_from_cmnd = 0;
+		if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
+				(0xf<<2) | (3<<7), 1,
+				"SYNCHRONIZE CACHE")) == 0)
+			reply = do_synchronize_cache(fsg);
+		break;
+
+	case SC_TEST_UNIT_READY:
+		fsg->data_size_from_cmnd = 0;
+		reply = check_command(fsg, 6, DATA_DIR_NONE,
+				0, 1,
+				"TEST UNIT READY");
+		break;
+
+	/* Although optional, this command is used by MS-Windows.  We
+	 * support a minimal version: BytChk must be 0. */
+	case SC_VERIFY:
+		fsg->data_size_from_cmnd = 0;
+		if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
+				(1<<1) | (0xf<<2) | (3<<7), 1,
+				"VERIFY")) == 0)
+			reply = do_verify(fsg);
+		break;
+
+	case SC_WRITE_6:
+		i = fsg->cmnd[4];
+		fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+		if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
+				(7<<1) | (1<<4), 1,
+				"WRITE(6)")) == 0)
+			reply = do_write(fsg);
+		break;
+
+	case SC_WRITE_10:
+		fsg->data_size_from_cmnd = get_be16(&fsg->cmnd[7]) << 9;
+		if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
+				(1<<1) | (0xf<<2) | (3<<7), 1,
+				"WRITE(10)")) == 0)
+			reply = do_write(fsg);
+		break;
+
+	case SC_WRITE_12:
+		fsg->data_size_from_cmnd = get_be32(&fsg->cmnd[6]) << 9;
+		if ((reply = check_command(fsg, 12, DATA_DIR_FROM_HOST,
+				(1<<1) | (0xf<<2) | (0xf<<6), 1,
+				"WRITE(12)")) == 0)
+			reply = do_write(fsg);
+		break;
+
+	/* Some mandatory commands that we recognize but don't implement.
+	 * They don't mean much in this setting.  It's left as an exercise
+	 * for anyone interested to implement RESERVE and RELEASE in terms
+	 * of Posix locks. */
+	case SC_FORMAT_UNIT:
+	case SC_RELEASE:
+	case SC_RESERVE:
+	case SC_SEND_DIAGNOSTIC:
+		/* Fall through */
+
+	default:
+		fsg->data_size_from_cmnd = 0;
+		sprintf(unknown, "Unknown x%02x", fsg->cmnd[0]);
+		if ((reply = check_command(fsg, fsg->cmnd_size,
+				DATA_DIR_UNKNOWN, 0xff, 0, unknown)) == 0) {
+			fsg->curlun->sense_data = SS_INVALID_COMMAND;
+			reply = -EINVAL;
+		}
+		break;
+	}
+	up_read(&fsg->filesem);
+
+	VDBG(fsg, "reply: %d, fsg->data_size_from_cmnd: %d\n",
+			reply, fsg->data_size_from_cmnd);
+	if (reply == -EINTR || signal_pending(current))
+		return -EINTR;
+
+	/* Set up the single reply buffer for finish_reply() */
+	if (reply == -EINVAL)
+		reply = 0;		/* Error reply length */
+	if (reply >= 0 && fsg->data_dir == DATA_DIR_TO_HOST) {
+		reply = min((u32) reply, fsg->data_size_from_cmnd);
+		bh->inreq->length = reply;
+		bh->state = BUF_STATE_FULL;
+		fsg->residue -= reply;
+	}				/* Otherwise it's already set */
+
+	return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+	struct usb_request	*req = bh->outreq;
+	struct bulk_cb_wrap	*cbw = req->buf;
+
+	/* Was this a real packet? */
+	if (req->status)
+		return -EINVAL;
+
+	/* Is the CBW valid? */
+	if (req->actual != USB_BULK_CB_WRAP_LEN ||
+			cbw->Signature != __constant_cpu_to_le32(
+				USB_BULK_CB_SIG)) {
+		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
+				req->actual,
+				le32_to_cpu(cbw->Signature));
+		return -EINVAL;
+	}
+
+	/* Is the CBW meaningful? */
+	if (cbw->Lun >= MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
+			cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
+		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
+				"cmdlen %u\n",
+				cbw->Lun, cbw->Flags, cbw->Length);
+		return -EINVAL;
+	}
+
+	/* Save the command for later */
+	fsg->cmnd_size = cbw->Length;
+	memcpy(fsg->cmnd, cbw->CDB, fsg->cmnd_size);
+	if (cbw->Flags & USB_BULK_IN_FLAG)
+		fsg->data_dir = DATA_DIR_TO_HOST;
+	else
+		fsg->data_dir = DATA_DIR_FROM_HOST;
+	fsg->data_size = le32_to_cpu(cbw->DataTransferLength);
+	if (fsg->data_size == 0)
+		fsg->data_dir = DATA_DIR_NONE;
+	fsg->lun = cbw->Lun;
+	fsg->tag = cbw->Tag;
+	return 0;
+}
+
+
+static int get_next_command(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh;
+	int			rc = 0;
+
+	/* Wait for the next buffer to become available */
+	bh = fsg->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+
+	/* Queue a request to read a Bulk-only CBW */
+	set_bulk_out_req_length(fsg, bh, USB_BULK_CB_WRAP_LEN);
+	start_transfer(fsg, fsg->bulk_out, bh->outreq,
+			&bh->outreq_busy, &bh->state);
+
+	/* We will drain the buffer in software, which means we
+	 * can reuse it for the next filling.  No need to advance
+	 * next_buffhd_to_fill. */
+
+	/* Wait for the CBW to arrive */
+	while (bh->state != BUF_STATE_FULL) {
+		rc = sleep_thread(fsg);
+		if (rc)
+			return rc;
+	}
+	smp_rmb();
+	rc = received_cbw(fsg, bh);
+	bh->state = BUF_STATE_EMPTY;
+
+	return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int enable_endpoint(struct fsg_dev *fsg, struct usb_ep *ep,
+		const struct usb_endpoint_descriptor *d)
+{
+	int	rc;
+
+	DBG(fsg, "usb_ep_enable %s\n", ep->name);
+	ep->driver_data = fsg;
+	rc = usb_ep_enable(ep, d);
+	if (rc)
+		ERROR(fsg, "can't enable %s, result %d\n", ep->name, rc);
+	return rc;
+}
+
+static int alloc_request(struct fsg_dev *fsg, struct usb_ep *ep,
+		struct usb_request **preq)
+{
+	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
+	if (*preq)
+		return 0;
+	ERROR(fsg, "can't allocate request for %s\n", ep->name);
+	return -ENOMEM;
+}
+
+/*
+ * Reset interface setting and re-init endpoint state (toggle etc).
+ * Call with altsetting < 0 to disable the interface.  The only other
+ * available altsetting is 0, which enables the interface.
+ */
+static int do_set_interface(struct fsg_dev *fsg, int altsetting)
+{
+	struct usb_composite_dev *cdev = fsg->cdev;
+	int	rc = 0;
+	int	i;
+	const struct usb_endpoint_descriptor	*d;
+
+	if (fsg->running)
+		DBG(fsg, "reset interface\n");
+
+reset:
+	/* Deallocate the requests */
+	for (i = 0; i < NUM_BUFFERS; ++i) {
+		struct fsg_buffhd *bh = &fsg->buffhds[i];
+
+		if (bh->inreq) {
+			usb_ep_free_request(fsg->bulk_in, bh->inreq);
+			bh->inreq = NULL;
+		}
+		if (bh->outreq) {
+			usb_ep_free_request(fsg->bulk_out, bh->outreq);
+			bh->outreq = NULL;
+		}
+	}
+
+	/* Disable the endpoints */
+	if (fsg->bulk_in_enabled) {
+		DBG(fsg, "usb_ep_disable %s\n", fsg->bulk_in->name);
+		usb_ep_disable(fsg->bulk_in);
+		fsg->bulk_in_enabled = 0;
+	}
+	if (fsg->bulk_out_enabled) {
+		DBG(fsg, "usb_ep_disable %s\n", fsg->bulk_out->name);
+		usb_ep_disable(fsg->bulk_out);
+		fsg->bulk_out_enabled = 0;
+	}
+
+	fsg->running = 0;
+	if (altsetting < 0 || rc != 0)
+		return rc;
+
+	DBG(fsg, "set interface %d\n", altsetting);
+
+	/* Enable the endpoints */
+	d = ep_desc(cdev->gadget, &fs_bulk_in_desc, &hs_bulk_in_desc);
+	if ((rc = enable_endpoint(fsg, fsg->bulk_in, d)) != 0)
+		goto reset;
+	fsg->bulk_in_enabled = 1;
+
+	d = ep_desc(cdev->gadget, &fs_bulk_out_desc, &hs_bulk_out_desc);
+	if ((rc = enable_endpoint(fsg, fsg->bulk_out, d)) != 0)
+		goto reset;
+	fsg->bulk_out_enabled = 1;
+	fsg->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
+
+	/* Allocate the requests */
+	for (i = 0; i < NUM_BUFFERS; ++i) {
+		struct fsg_buffhd	*bh = &fsg->buffhds[i];
+
+		rc = alloc_request(fsg, fsg->bulk_in, &bh->inreq);
+		if (rc != 0)
+			goto reset;
+		rc = alloc_request(fsg, fsg->bulk_out, &bh->outreq);
+		if (rc != 0)
+			goto reset;
+		bh->inreq->buf = bh->outreq->buf = bh->buf;
+		bh->inreq->context = bh->outreq->context = bh;
+		bh->inreq->complete = bulk_in_complete;
+		bh->outreq->complete = bulk_out_complete;
+	}
+
+	fsg->running = 1;
+	for (i = 0; i < fsg->nluns; ++i)
+		fsg->luns[i].unit_attention_data = SS_RESET_OCCURRED;
+
+	return rc;
+}
+
+static void adjust_wake_lock(struct fsg_dev *fsg)
+{
+	int ums_active = 0;
+	int i;
+
+	spin_lock_irq(&fsg->lock);
+
+	if (fsg->config) {
+		for (i = 0; i < fsg->nluns; ++i) {
+			if (backing_file_is_open(&fsg->luns[i]))
+				ums_active = 1;
+		}
+	}
+
+	if (ums_active)
+		wake_lock(&fsg->wake_lock);
+	else
+		wake_unlock(&fsg->wake_lock);
+
+	spin_unlock_irq(&fsg->lock);
+}
+
+/*
+ * Change our operational configuration.  This code must agree with the code
+ * that returns config descriptors, and with interface altsetting code.
+ *
+ * It's also responsible for power management interactions.  Some
+ * configurations might not work with our current power sources.
+ * For now we just assume the gadget is always self-powered.
+ */
+static int do_set_config(struct fsg_dev *fsg, u8 new_config)
+{
+	int	rc = 0;
+
+	if (new_config == fsg->config)
+		return rc;
+
+	/* Disable the single interface */
+	if (fsg->config != 0) {
+		DBG(fsg, "reset config\n");
+		fsg->config = 0;
+		rc = do_set_interface(fsg, -1);
+	}
+
+	/* Enable the interface */
+	if (new_config != 0) {
+		fsg->config = new_config;
+		rc = do_set_interface(fsg, 0);
+		if (rc != 0)
+			fsg->config = 0;	/* Reset on errors */
+		else
+			INFO(fsg, "config #%d\n", fsg->config);
+	}
+
+	switch_set_state(&fsg->sdev, new_config);
+	adjust_wake_lock(fsg);
+	return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static void handle_exception(struct fsg_dev *fsg)
+{
+	siginfo_t		info;
+	int			sig;
+	int			i;
+	struct fsg_buffhd	*bh;
+	enum fsg_state		old_state;
+	u8			new_config;
+	struct lun		*curlun;
+	int			rc;
+
+	DBG(fsg, "handle_exception state: %d\n", (int)fsg->state);
+	/* Clear the existing signals.  Anything but SIGUSR1 is converted
+	 * into a high-priority EXIT exception. */
+	for (;;) {
+		sig = dequeue_signal_lock(current, &current->blocked, &info);
+		if (!sig)
+			break;
+		if (sig != SIGUSR1) {
+			if (fsg->state < FSG_STATE_EXIT)
+				DBG(fsg, "Main thread exiting on signal\n");
+			raise_exception(fsg, FSG_STATE_EXIT);
+		}
+	}
+
+	/* Clear out the controller's fifos */
+	if (fsg->bulk_in_enabled)
+		usb_ep_fifo_flush(fsg->bulk_in);
+	if (fsg->bulk_out_enabled)
+		usb_ep_fifo_flush(fsg->bulk_out);
+
+	/* Reset the I/O buffer states and pointers, the SCSI
+	 * state, and the exception.  Then invoke the handler. */
+	spin_lock_irq(&fsg->lock);
+
+	for (i = 0; i < NUM_BUFFERS; ++i) {
+		bh = &fsg->buffhds[i];
+		bh->state = BUF_STATE_EMPTY;
+	}
+	fsg->next_buffhd_to_fill = fsg->next_buffhd_to_drain =
+			&fsg->buffhds[0];
+
+	new_config = fsg->new_config;
+	old_state = fsg->state;
+
+	if (old_state == FSG_STATE_ABORT_BULK_OUT)
+		fsg->state = FSG_STATE_STATUS_PHASE;
+	else {
+		for (i = 0; i < fsg->nluns; ++i) {
+			curlun = &fsg->luns[i];
+			curlun->prevent_medium_removal = 0;
+			curlun->sense_data = curlun->unit_attention_data =
+					SS_NO_SENSE;
+			curlun->sense_data_info = 0;
+			curlun->info_valid = 0;
+		}
+		fsg->state = FSG_STATE_IDLE;
+	}
+	spin_unlock_irq(&fsg->lock);
+
+	/* Carry out any extra actions required for the exception */
+	switch (old_state) {
+	default:
+		break;
+
+	case FSG_STATE_ABORT_BULK_OUT:
+		DBG(fsg, "FSG_STATE_ABORT_BULK_OUT\n");
+		spin_lock_irq(&fsg->lock);
+		if (fsg->state == FSG_STATE_STATUS_PHASE)
+			fsg->state = FSG_STATE_IDLE;
+		spin_unlock_irq(&fsg->lock);
+		break;
+
+	case FSG_STATE_RESET:
+		/* really not much to do here */
+		break;
+
+	case FSG_STATE_CONFIG_CHANGE:
+		rc = do_set_config(fsg, new_config);
+		if (new_config == 0) {
+			/* We're using the backing file */
+			down_read(&fsg->filesem);
+			fsync_all(fsg);
+			up_read(&fsg->filesem);
+		}
+		break;
+
+	case FSG_STATE_EXIT:
+	case FSG_STATE_TERMINATED:
+		do_set_config(fsg, 0);			/* Free resources */
+		spin_lock_irq(&fsg->lock);
+		fsg->state = FSG_STATE_TERMINATED;	/* Stop the thread */
+		spin_unlock_irq(&fsg->lock);
+		break;
+	}
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int fsg_main_thread(void *fsg_)
+{
+	struct fsg_dev		*fsg = fsg_;
+
+	/* Allow the thread to be killed by a signal, but set the signal mask
+	 * to block everything but INT, TERM, KILL, and USR1. */
+	allow_signal(SIGINT);
+	allow_signal(SIGTERM);
+	allow_signal(SIGKILL);
+	allow_signal(SIGUSR1);
+
+	/* Allow the thread to be frozen */
+	set_freezable();
+
+	/* Arrange for userspace references to be interpreted as kernel
+	 * pointers.  That way we can pass a kernel pointer to a routine
+	 * that expects a __user pointer and it will work okay. */
+	set_fs(get_ds());
+
+	/* The main loop */
+	while (fsg->state != FSG_STATE_TERMINATED) {
+		if (exception_in_progress(fsg) || signal_pending(current)) {
+			handle_exception(fsg);
+			continue;
+		}
+
+		if (!fsg->running) {
+			sleep_thread(fsg);
+			continue;
+		}
+
+		if (get_next_command(fsg))
+			continue;
+
+		spin_lock_irq(&fsg->lock);
+		if (!exception_in_progress(fsg))
+			fsg->state = FSG_STATE_DATA_PHASE;
+		spin_unlock_irq(&fsg->lock);
+
+		if (do_scsi_command(fsg) || finish_reply(fsg))
+			continue;
+
+		spin_lock_irq(&fsg->lock);
+		if (!exception_in_progress(fsg))
+			fsg->state = FSG_STATE_STATUS_PHASE;
+		spin_unlock_irq(&fsg->lock);
+
+		if (send_status(fsg))
+			continue;
+
+		spin_lock_irq(&fsg->lock);
+		if (!exception_in_progress(fsg))
+			fsg->state = FSG_STATE_IDLE;
+		spin_unlock_irq(&fsg->lock);
+		}
+
+	spin_lock_irq(&fsg->lock);
+	fsg->thread_task = NULL;
+	spin_unlock_irq(&fsg->lock);
+
+	/* In case we are exiting because of a signal, unregister the
+	 * gadget driver and close the backing file. */
+	if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags))
+		close_all_backing_files(fsg);
+
+	/* Let the unbind and cleanup routines know the thread has exited */
+	complete_and_exit(&fsg->thread_notifier, 0);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* If the next two routines are called while the gadget is registered,
+ * the caller must own fsg->filesem for writing. */
+
+static int open_backing_file(struct fsg_dev *fsg, struct lun *curlun,
+	const char *filename)
+{
+	int				ro;
+	struct file			*filp = NULL;
+	int				rc = -EINVAL;
+	struct inode			*inode = NULL;
+	loff_t				size;
+	loff_t				num_sectors;
+
+	/* R/W if we can, R/O if we must */
+	ro = curlun->ro;
+	if (!ro) {
+		filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
+		if (-EROFS == PTR_ERR(filp))
+			ro = 1;
+	}
+	if (ro)
+		filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
+	if (IS_ERR(filp)) {
+		LINFO(curlun, "unable to open backing file: %s\n", filename);
+		return PTR_ERR(filp);
+	}
+
+	if (!(filp->f_mode & FMODE_WRITE))
+		ro = 1;
+
+	if (filp->f_path.dentry)
+		inode = filp->f_path.dentry->d_inode;
+	if (inode && S_ISBLK(inode->i_mode)) {
+		if (bdev_read_only(inode->i_bdev))
+			ro = 1;
+	} else if (!inode || !S_ISREG(inode->i_mode)) {
+		LINFO(curlun, "invalid file type: %s\n", filename);
+		goto out;
+	}
+
+	/* If we can't read the file, it's no good.
+	 * If we can't write the file, use it read-only. */
+	if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) {
+		LINFO(curlun, "file not readable: %s\n", filename);
+		goto out;
+	}
+	if (!(filp->f_op->write || filp->f_op->aio_write))
+		ro = 1;
+
+	size = i_size_read(inode->i_mapping->host);
+	if (size < 0) {
+		LINFO(curlun, "unable to find file size: %s\n", filename);
+		rc = (int) size;
+		goto out;
+	}
+	num_sectors = size >> 9;	/* File size in 512-byte sectors */
+	if (num_sectors == 0) {
+		LINFO(curlun, "file too small: %s\n", filename);
+		rc = -ETOOSMALL;
+		goto out;
+	}
+
+	get_file(filp);
+	curlun->ro = ro;
+	curlun->filp = filp;
+	curlun->file_length = size;
+	curlun->num_sectors = num_sectors;
+	LDBG(curlun, "open backing file: %s size: %lld num_sectors: %lld\n",
+			filename, size, num_sectors);
+	rc = 0;
+	adjust_wake_lock(fsg);
+
+out:
+	filp_close(filp, current->files);
+	return rc;
+}
+
+
+static void close_backing_file(struct fsg_dev *fsg, struct lun *curlun)
+{
+	if (curlun->filp) {
+		int rc;
+
+		/*
+		 * XXX: San: Ugly hack here added to ensure that
+		 * our pages get synced to disk.
+		 * Also drop caches here just to be extra-safe
+		 */
+		rc = vfs_fsync(curlun->filp, curlun->filp->f_path.dentry, 1);
+		if (rc < 0)
+			printk(KERN_ERR "ums: Error syncing data (%d)\n", rc);
+		/* drop_pagecache and drop_slab are no longer available */
+		/* drop_pagecache(); */
+		/* drop_slab(); */
+
+		LDBG(curlun, "close backing file\n");
+		fput(curlun->filp);
+		curlun->filp = NULL;
+		adjust_wake_lock(fsg);
+	}
+}
+
+static void close_all_backing_files(struct fsg_dev *fsg)
+{
+	int	i;
+
+	for (i = 0; i < fsg->nluns; ++i)
+		close_backing_file(fsg, &fsg->luns[i]);
+}
+
+static ssize_t show_file(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct lun	*curlun = dev_to_lun(dev);
+	struct fsg_dev	*fsg = dev_get_drvdata(dev);
+	char		*p;
+	ssize_t		rc;
+
+	down_read(&fsg->filesem);
+	if (backing_file_is_open(curlun)) {	/* Get the complete pathname */
+		p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
+		if (IS_ERR(p))
+			rc = PTR_ERR(p);
+		else {
+			rc = strlen(p);
+			memmove(buf, p, rc);
+			buf[rc] = '\n';		/* Add a newline */
+			buf[++rc] = 0;
+		}
+	} else {				/* No file, return 0 bytes */
+		*buf = 0;
+		rc = 0;
+	}
+	up_read(&fsg->filesem);
+	return rc;
+}
+
+static ssize_t store_file(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct lun	*curlun = dev_to_lun(dev);
+	struct fsg_dev	*fsg = dev_get_drvdata(dev);
+	int		rc = 0;
+
+	DBG(fsg, "store_file: \"%s\"\n", buf);
+#if 0
+	/* disabled because we need to allow closing the backing file if the media was removed */
+	if (curlun->prevent_medium_removal && backing_file_is_open(curlun)) {
+		LDBG(curlun, "eject attempt prevented\n");
+		return -EBUSY;				/* "Door is locked" */
+	}
+#endif
+
+	/* Remove a trailing newline */
+	if (count > 0 && buf[count-1] == '\n')
+		((char *) buf)[count-1] = 0;
+
+	/* Eject current medium */
+	down_write(&fsg->filesem);
+	if (backing_file_is_open(curlun)) {
+		close_backing_file(fsg, curlun);
+		curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
+	}
+
+	/* Load new medium */
+	if (count > 0 && buf[0]) {
+		rc = open_backing_file(fsg, curlun, buf);
+		if (rc == 0)
+			curlun->unit_attention_data =
+					SS_NOT_READY_TO_READY_TRANSITION;
+	}
+	up_write(&fsg->filesem);
+	return (rc < 0 ? rc : count);
+}
+
+
+static DEVICE_ATTR(file, 0444, show_file, store_file);
+
+/*-------------------------------------------------------------------------*/
+
+static void fsg_release(struct kref *ref)
+{
+	struct fsg_dev	*fsg = container_of(ref, struct fsg_dev, ref);
+
+	kfree(fsg->luns);
+	kfree(fsg);
+}
+
+static void lun_release(struct device *dev)
+{
+	struct fsg_dev	*fsg = dev_get_drvdata(dev);
+
+	kref_put(&fsg->ref, fsg_release);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int __init fsg_alloc(void)
+{
+	struct fsg_dev		*fsg;
+
+	fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
+	if (!fsg)
+		return -ENOMEM;
+	spin_lock_init(&fsg->lock);
+	init_rwsem(&fsg->filesem);
+	kref_init(&fsg->ref);
+	init_completion(&fsg->thread_notifier);
+
+	the_fsg = fsg;
+	return 0;
+}
+
+static ssize_t print_switch_name(struct switch_dev *sdev, char *buf)
+{
+	return sprintf(buf, "%s\n", DRIVER_NAME);
+}
+
+static ssize_t print_switch_state(struct switch_dev *sdev, char *buf)
+{
+	struct fsg_dev	*fsg = container_of(sdev, struct fsg_dev, sdev);
+	return sprintf(buf, "%s\n", (fsg->config ? "online" : "offline"));
+}
+
+static void
+fsg_function_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct fsg_dev	*fsg = func_to_dev(f);
+	int			i;
+	struct lun		*curlun;
+
+	DBG(fsg, "fsg_function_unbind\n");
+	clear_bit(REGISTERED, &fsg->atomic_bitflags);
+
+	/* Unregister the sysfs attribute files and the LUNs */
+	for (i = 0; i < fsg->nluns; ++i) {
+		curlun = &fsg->luns[i];
+		if (curlun->registered) {
+			device_remove_file(&curlun->dev, &dev_attr_file);
+			device_unregister(&curlun->dev);
+			curlun->registered = 0;
+		}
+	}
+
+	/* If the thread isn't already dead, tell it to exit now */
+	if (fsg->state != FSG_STATE_TERMINATED) {
+		raise_exception(fsg, FSG_STATE_EXIT);
+		wait_for_completion(&fsg->thread_notifier);
+
+		/* The cleanup routine waits for this completion also */
+		complete(&fsg->thread_notifier);
+	}
+
+	/* Free the data buffers */
+	for (i = 0; i < NUM_BUFFERS; ++i)
+		kfree(fsg->buffhds[i].buf);
+}
+
+static int __init
+fsg_function_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct fsg_dev	*fsg = func_to_dev(f);
+	int			rc;
+	int			i;
+	int			id;
+	struct lun		*curlun;
+	struct usb_ep		*ep;
+	char			*pathbuf, *p;
+
+	fsg->cdev = cdev;
+	DBG(fsg, "fsg_function_bind\n");
+
+	dev_attr_file.attr.mode = 0644;
+
+	/* Find out how many LUNs there should be */
+	i = fsg->nluns;
+	if (i == 0)
+		i = 1;
+	if (i > MAX_LUNS) {
+		ERROR(fsg, "invalid number of LUNs: %d\n", i);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	/* Create the LUNs, open their backing files, and register the
+	 * LUN devices in sysfs. */
+	fsg->luns = kzalloc(i * sizeof(struct lun), GFP_KERNEL);
+	if (!fsg->luns) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	fsg->nluns = i;
+
+	for (i = 0; i < fsg->nluns; ++i) {
+		curlun = &fsg->luns[i];
+		curlun->ro = 0;
+		curlun->dev.release = lun_release;
+		curlun->dev.parent = &cdev->gadget->dev;
+		dev_set_drvdata(&curlun->dev, fsg);
+		snprintf(curlun->dev.bus_id, BUS_ID_SIZE,
+				"lun%d", i);
+
+		rc = device_register(&curlun->dev);
+		if (rc != 0) {
+			INFO(fsg, "failed to register LUN%d: %d\n", i, rc);
+			goto out;
+		}
+		rc = device_create_file(&curlun->dev, &dev_attr_file);
+		if (rc != 0) {
+			ERROR(fsg, "device_create_file failed: %d\n", rc);
+			device_unregister(&curlun->dev);
+			goto out;
+		}
+		curlun->registered = 1;
+		kref_get(&fsg->ref);
+	}
+
+	/* allocate interface ID(s) */
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	intf_desc.bInterfaceNumber = id;
+
+	ep = usb_ep_autoconfig(cdev->gadget, &fs_bulk_in_desc);
+	if (!ep)
+		goto autoconf_fail;
+	ep->driver_data = fsg;		/* claim the endpoint */
+	fsg->bulk_in = ep;
+
+	ep = usb_ep_autoconfig(cdev->gadget, &fs_bulk_out_desc);
+	if (!ep)
+		goto autoconf_fail;
+	ep->driver_data = fsg;		/* claim the endpoint */
+	fsg->bulk_out = ep;
+
+	rc = -ENOMEM;
+
+	if (gadget_is_dualspeed(cdev->gadget)) {
+		/* Assume endpoint addresses are the same for both speeds */
+		hs_bulk_in_desc.bEndpointAddress =
+				fs_bulk_in_desc.bEndpointAddress;
+		hs_bulk_out_desc.bEndpointAddress =
+				fs_bulk_out_desc.bEndpointAddress;
+
+		f->hs_descriptors = hs_function;
+	}
+
+	/* Allocate the data buffers */
+	for (i = 0; i < NUM_BUFFERS; ++i) {
+		struct fsg_buffhd	*bh = &fsg->buffhds[i];
+
+		/* Allocate for the bulk-in endpoint.  We assume that
+		 * the buffer will also work with the bulk-out (and
+		 * interrupt-in) endpoint. */
+		bh->buf = kmalloc(fsg->buf_size, GFP_KERNEL);
+		if (!bh->buf)
+			goto out;
+		bh->next = bh + 1;
+	}
+	fsg->buffhds[NUM_BUFFERS - 1].next = &fsg->buffhds[0];
+
+	fsg->thread_task = kthread_create(fsg_main_thread, fsg,
+			shortname);
+	if (IS_ERR(fsg->thread_task)) {
+		rc = PTR_ERR(fsg->thread_task);
+		ERROR(fsg, "kthread_create failed: %d\n", rc);
+		goto out;
+	}
+
+	INFO(fsg, "Number of LUNs=%d\n", fsg->nluns);
+
+	pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+	for (i = 0; i < fsg->nluns; ++i) {
+		curlun = &fsg->luns[i];
+		if (backing_file_is_open(curlun)) {
+			p = NULL;
+			if (pathbuf) {
+				p = d_path(&curlun->filp->f_path,
+					   pathbuf, PATH_MAX);
+				if (IS_ERR(p))
+					p = NULL;
+			}
+			LINFO(curlun, "ro=%d, file: %s\n",
+					curlun->ro, (p ? p : "(error)"));
+		}
+	}
+	kfree(pathbuf);
+
+	set_bit(REGISTERED, &fsg->atomic_bitflags);
+
+	/* Tell the thread to start working */
+	wake_up_process(fsg->thread_task);
+	return 0;
+
+autoconf_fail:
+	ERROR(fsg, "unable to autoconfigure all endpoints\n");
+	rc = -ENOTSUPP;
+
+out:
+	DBG(fsg, "fsg_function_bind failed: %d\n", rc);
+	fsg->state = FSG_STATE_TERMINATED;	/* The thread is dead */
+	fsg_function_unbind(c, f);
+	close_all_backing_files(fsg);
+	return rc;
+}
+
+static int fsg_function_set_alt(struct usb_function *f,
+		unsigned intf, unsigned alt)
+{
+	struct fsg_dev	*fsg = func_to_dev(f);
+	DBG(fsg, "fsg_function_set_alt intf: %d alt: %d\n", intf, alt);
+	fsg->new_config = 1;
+	raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
+	return 0;
+}
+
+static void fsg_function_disable(struct usb_function *f)
+{
+	struct fsg_dev	*fsg = func_to_dev(f);
+	DBG(fsg, "fsg_function_disable\n");
+	fsg->new_config = 0;
+	raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
+}
+
+int __init mass_storage_function_add(struct usb_composite_dev *cdev,
+	struct usb_configuration *c, int nluns)
+{
+	int		rc;
+	struct fsg_dev	*fsg;
+
+	printk(KERN_INFO "mass_storage_function_add\n");
+	rc = fsg_alloc();
+	if (rc)
+		return rc;
+	fsg = the_fsg;
+	fsg->nluns = nluns;
+
+	spin_lock_init(&fsg->lock);
+	init_rwsem(&fsg->filesem);
+	kref_init(&fsg->ref);
+	init_completion(&fsg->thread_notifier);
+
+	the_fsg->buf_size = BULK_BUFFER_SIZE;
+	the_fsg->sdev.name = DRIVER_NAME;
+	the_fsg->sdev.print_name = print_switch_name;
+	the_fsg->sdev.print_state = print_switch_state;
+	rc = switch_dev_register(&the_fsg->sdev);
+	if (rc < 0)
+		goto err_switch_dev_register;
+
+	wake_lock_init(&the_fsg->wake_lock, WAKE_LOCK_SUSPEND,
+		       "usb_mass_storage");
+
+	fsg->cdev = cdev;
+	fsg->function.name = shortname;
+	fsg->function.descriptors = fs_function;
+	fsg->function.bind = fsg_function_bind;
+	fsg->function.unbind = fsg_function_unbind;
+	fsg->function.setup = fsg_function_setup;
+	fsg->function.set_alt = fsg_function_set_alt;
+	fsg->function.disable = fsg_function_disable;
+
+	rc = usb_add_function(c, &fsg->function);
+	if (rc != 0)
+		goto err_usb_add_function;
+
+	return 0;
+
+err_usb_add_function:
+	switch_dev_unregister(&the_fsg->sdev);
+err_switch_dev_register:
+	kref_put(&the_fsg->ref, fsg_release);
+
+	return rc;
+}
--- /dev/null
+++ b/drivers/usb/gadget/f_mass_storage.h
@@ -0,0 +1,52 @@
+/*
+ * drivers/usb/gadget/f_mass_storage.h
+ *
+ * Function Driver for USB Mass Storage
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * Based heavily on the file_storage gadget driver in
+ * drivers/usb/gadget/file_storage.c and licensed under the same terms:
+ *
+ * Copyright (C) 2003-2007 Alan Stern
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __F_MASS_STORAGE_H
+#define __F_MASS_STORAGE_H
+
+int mass_storage_function_add(struct usb_composite_dev *cdev,
+	struct usb_configuration *c, int nluns);
+
+#endif /* __F_MASS_STORAGE_H */
--- /dev/null
+++ b/include/linux/usb/android.h
@@ -0,0 +1,40 @@
+/*
+ * Platform data for Android USB
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+#ifndef	__LINUX_USB_ANDROID_H
+#define	__LINUX_USB_ANDROID_H
+
+struct android_usb_platform_data {
+	/* USB device descriptor fields */
+	__u16 vendor_id;
+
+	/* Default product ID. */
+	__u16 product_id;
+
+	/* Product ID when adb is enabled. */
+	__u16 adb_product_id;
+
+	__u16 version;
+
+	char *product_name;
+	char *manufacturer_name;
+	char *serial_number;
+
+	/* number of LUNS for mass storage function */
+	int nluns;
+};
+
+#endif	/* __LINUX_USB_ANDROID_H */