usb:composite: USB Mass Storage - f_mass_storage.c from Linux kernel

The f_mass_storage.c source file from v2.6.36 Linux kernel.

commit 8876f5e7d3b2a320777dd4f6f5301d474c97a06c
Author: Michal Nazarewicz <m.nazarewicz@samsung.com>
Date:   Mon Jun 21 13:57:09 2010 +0200

USB: gadget: f_mass_storage: added eject callback

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Piotr Wilczek <p.wilczek@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Marek Vasut <marek.vasut@gmail.com>

1 files changed, 2793 insertions, 0 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
new file mode 100644
index 0000000..c28866f
--- /dev/null
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -0,0 +1,2793 @@
+/*
+ * f_mass_storage.c -- Mass Storage USB Composite Function
+ *
+ * Copyright (C) 2003-2008 Alan Stern
+ * Copyright (C) 2009 Samsung Electronics
+ *                    Author: Michal Nazarewicz <m.nazarewicz@samsung.com>
+ * 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.
+ */
+
+
+/*
+ * The Mass Storage Function acts as a USB Mass Storage device,
+ * appearing to the host as a disk drive or as a CD-ROM drive.  In
+ * addition to providing an example of a genuinely useful composite
+ * function for a USB device, it also illustrates a technique of
+ * double-buffering for increased throughput.
+ *
+ * Function supports multiple logical units (LUNs).  Backing storage
+ * for each LUN is provided by a regular file or a block device.
+ * Access for each LUN can be limited to read-only.  Moreover, the
+ * function can indicate that LUN is removable and/or CD-ROM.  (The
+ * later implies read-only access.)
+ *
+ * MSF is configured by specifying a fsg_config structure.  It has the
+ * following fields:
+ *
+ *	nluns		Number of LUNs function have (anywhere from 1
+ *				to FSG_MAX_LUNS which is 8).
+ *	luns		An array of LUN configuration values.  This
+ *				should be filled for each LUN that
+ *				function will include (ie. for "nluns"
+ *				LUNs).  Each element of the array has
+ *				the following fields:
+ *	->filename	The path to the backing file for the LUN.
+ *				Required if LUN is not marked as
+ *				removable.
+ *	->ro		Flag specifying access to the LUN shall be
+ *				read-only.  This is implied if CD-ROM
+ *				emulation is enabled as well as when
+ *				it was impossible to open "filename"
+ *				in R/W mode.
+ *	->removable	Flag specifying that LUN shall be indicated as
+ *				being removable.
+ *	->cdrom		Flag specifying that LUN shall be reported as
+ *				being a CD-ROM.
+ *
+ *	lun_name_format	A printf-like format for names of the LUN
+ *				devices.  This determines how the
+ *				directory in sysfs will be named.
+ *				Unless you are using several MSFs in
+ *				a single gadget (as opposed to single
+ *				MSF in many configurations) you may
+ *				leave it as NULL (in which case
+ *				"lun%d" will be used).  In the format
+ *				you can use "%d" to index LUNs for
+ *				MSF's with more than one LUN.  (Beware
+ *				that there is only one integer given
+ *				as an argument for the format and
+ *				specifying invalid format may cause
+ *				unspecified behaviour.)
+ *	thread_name	Name of the kernel thread process used by the
+ *				MSF.  You can safely set it to NULL
+ *				(in which case default "file-storage"
+ *				will be used).
+ *
+ *	vendor_name
+ *	product_name
+ *	release		Information used as a reply to INQUIRY
+ *				request.  To use default set to NULL,
+ *				NULL, 0xffff respectively.  The first
+ *				field should be 8 and the second 16
+ *				characters or less.
+ *
+ *	can_stall	Set to permit function to halt bulk endpoints.
+ *				Disabled on some USB devices known not
+ *				to work correctly.  You should set it
+ *				to true.
+ *
+ * If "removable" is not set for a LUN then a backing file must be
+ * specified.  If it is set, then NULL filename means the LUN's medium
+ * is not loaded (an empty string as "filename" in the fsg_config
+ * structure causes error).  The CD-ROM emulation includes a single
+ * data track and no audio tracks; hence there need be only one
+ * backing file per LUN.  Note also that the CD-ROM block length is
+ * set to 512 rather than the more common value 2048.
+ *
+ *
+ * MSF includes support for module parameters.  If gadget using it
+ * decides to use it, the following module parameters will be
+ * available:
+ *
+ *	file=filename[,filename...]
+ *			Names of the files or block devices used for
+ *				backing storage.
+ *	ro=b[,b...]	Default false, boolean for read-only access.
+ *	removable=b[,b...]
+ *			Default true, boolean for removable media.
+ *	cdrom=b[,b...]	Default false, boolean for whether to emulate
+ *				a CD-ROM drive.
+ *	luns=N		Default N = number of filenames, number of
+ *				LUNs to support.
+ *	stall		Default determined according to the type of
+ *				USB device controller (usually true),
+ *				boolean to permit the driver to halt
+ *				bulk endpoints.
+ *
+ * The module parameters may be prefixed with some string.  You need
+ * to consult gadget's documentation or source to verify whether it is
+ * using those module parameters and if it does what are the prefixes
+ * (look for FSG_MODULE_PARAMETERS() macro usage, what's inside it is
+ * the prefix).
+ *
+ *
+ * Requirements are modest; only a bulk-in and a bulk-out endpoint are
+ * needed.  The memory requirement amounts to two 16K buffers, size
+ * configurable by a parameter.  Support is included for both
+ * full-speed and high-speed operation.
+ *
+ * Note that the driver is slightly non-portable in that it assumes a
+ * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
+ * interrupt-in endpoints.  With most device controllers this isn't an
+ * issue, but there may be some with hardware restrictions that prevent
+ * a buffer from being used by more than one endpoint.
+ *
+ *
+ * The pathnames of the backing files and the ro settings are
+ * available in the attribute files "file" and "ro" in the lun<n> (or
+ * to be more precise in a directory which name comes from
+ * "lun_name_format" option!) subdirectory of the gadget's sysfs
+ * directory.  If the "removable" option is set, writing to these
+ * files will simulate ejecting/loading the medium (writing an empty
+ * line means eject) and adjusting a write-enable tab.  Changes to the
+ * ro setting are not allowed when the medium is loaded or if CD-ROM
+ * emulation is being used.
+ *
+ * When a LUN receive an "eject" SCSI request (Start/Stop Unit),
+ * if the LUN is removable, the backing file is released to simulate
+ * ejection.
+ *
+ *
+ * This function is heavily based on "File-backed Storage Gadget" by
+ * Alan Stern which in turn is heavily based on "Gadget Zero" by David
+ * Brownell.  The driver's SCSI command interface was based on the
+ * "Information technology - Small Computer System Interface - 2"
+ * document from X3T9.2 Project 375D, Revision 10L, 7-SEP-93,
+ * available at <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.
+ * The single exception is opcode 0x23 (READ FORMAT CAPACITIES), which
+ * was based on the "Universal Serial Bus Mass Storage Class UFI
+ * Command Specification" document, Revision 1.0, December 14, 1998,
+ * available at
+ * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
+ */
+
+
+/*
+ *				Driver Design
+ *
+ * The MSF is fairly straightforward.  There is a main kernel
+ * thread that handles most of the work.  Interrupt routines field
+ * callbacks from the controller driver: bulk- and interrupt-request
+ * completion notifications, endpoint-0 events, and disconnect events.
+ * Completion events are passed to the main thread by wakeup calls.  Many
+ * ep0 requests are handled at interrupt time, but SetInterface,
+ * SetConfiguration, and device reset requests are forwarded to the
+ * thread in the form of "exceptions" using SIGUSR1 signals (since they
+ * should interrupt any ongoing file I/O operations).
+ *
+ * The thread's main routine implements the standard command/data/status
+ * parts of a SCSI interaction.  It and its subroutines are full of tests
+ * for pending signals/exceptions -- all this polling is necessary since
+ * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
+ * indication that the driver really wants to be running in userspace.)
+ * An important point is that so long as the thread is alive it keeps an
+ * open reference to the backing file.  This will prevent unmounting
+ * the backing file's underlying filesystem and could cause problems
+ * during system shutdown, for example.  To prevent such problems, the
+ * thread catches INT, TERM, and KILL signals and converts them into
+ * an EXIT exception.
+ *
+ * In normal operation the main thread is started during the gadget's
+ * fsg_bind() callback and stopped during fsg_unbind().  But it can
+ * also exit when it receives a signal, and there's no point leaving
+ * the gadget running when the thread is dead.  At of this moment, MSF
+ * provides no way to deregister the gadget when thread dies -- maybe
+ * a callback functions is needed.
+ *
+ * To provide maximum throughput, the driver uses a circular pipeline of
+ * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
+ * arbitrarily long; in practice the benefits don't justify having more
+ * than 2 stages (i.e., double buffering).  But it helps to think of the
+ * pipeline as being a long one.  Each buffer head contains a bulk-in and
+ * a bulk-out request pointer (since the buffer can be used for both
+ * output and input -- directions always are given from the host's
+ * point of view) as well as a pointer to the buffer and various state
+ * variables.
+ *
+ * Use of the pipeline follows a simple protocol.  There is a variable
+ * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
+ * At any time that buffer head may still be in use from an earlier
+ * request, so each buffer head has a state variable indicating whether
+ * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
+ * buffer head to be EMPTY, filling the buffer either by file I/O or by
+ * USB I/O (during which the buffer head is BUSY), and marking the buffer
+ * head FULL when the I/O is complete.  Then the buffer will be emptied
+ * (again possibly by USB I/O, during which it is marked BUSY) and
+ * finally marked EMPTY again (possibly by a completion routine).
+ *
+ * A module parameter tells the driver to avoid stalling the bulk
+ * endpoints wherever the transport specification allows.  This is
+ * necessary for some UDCs like the SuperH, which cannot reliably clear a
+ * halt on a bulk endpoint.  However, under certain circumstances the
+ * Bulk-only specification requires a stall.  In such cases the driver
+ * will halt the endpoint and set a flag indicating that it should clear
+ * the halt in software during the next device reset.  Hopefully this
+ * will permit everything to work correctly.  Furthermore, although the
+ * specification allows the bulk-out endpoint to halt when the host sends
+ * too much data, implementing this would cause an unavoidable race.
+ * The driver will always use the "no-stall" approach for OUT transfers.
+ *
+ * One subtle point concerns sending status-stage responses for ep0
+ * requests.  Some of these requests, such as device reset, can involve
+ * interrupting an ongoing file I/O operation, which might take an
+ * arbitrarily long time.  During that delay the host might give up on
+ * the original ep0 request and issue a new one.  When that happens the
+ * driver should not notify the host about completion of the original
+ * request, as the host will no longer be waiting for it.  So the driver
+ * assigns to each ep0 request a unique tag, and it keeps track of the
+ * tag value of the request associated with a long-running exception
+ * (device-reset, interface-change, or configuration-change).  When the
+ * exception handler is finished, the status-stage response is submitted
+ * only if the current ep0 request tag is equal to the exception request
+ * tag.  Thus only the most recently received ep0 request will get a
+ * status-stage response.
+ *
+ * Warning: This driver source file is too long.  It ought to be split up
+ * into a header file plus about 3 separate .c files, to handle the details
+ * of the Gadget, USB Mass Storage, and SCSI protocols.
+ */
+
+/* #define VERBOSE_DEBUG */
+/* #define DUMP_MSGS */
+
+#include <config.h>
+#include <malloc.h>
+#include <common.h>
+
+#include <linux/err.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <usb_mass_storage.h>
+
+#include <asm/unaligned.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
+#include <usb/lin_gadget_compat.h>
+
+/*------------------------------------------------------------------------*/
+
+#define FSG_DRIVER_DESC	"Mass Storage Function"
+#define FSG_DRIVER_VERSION	"2012/06/5"
+
+static const char fsg_string_interface[] = "Mass Storage";
+
+
+#define FSG_NO_INTR_EP 1
+#define FSG_NO_DEVICE_STRINGS    1
+#define FSG_NO_OTG               1
+#define FSG_NO_INTR_EP           1
+
+#include "storage_common.c"
+
+/*-------------------------------------------------------------------------*/
+
+#define GFP_ATOMIC ((gfp_t) 0)
+#define PAGE_CACHE_SHIFT	12
+#define PAGE_CACHE_SIZE		(1 << PAGE_CACHE_SHIFT)
+#define kthread_create(...)	__builtin_return_address(0)
+#define wait_for_completion(...) do {} while (0)
+
+struct kref {int x; };
+struct completion {int x; };
+
+inline void set_bit(int nr, volatile void *addr)
+{
+	int	mask;
+	unsigned int *a = (unsigned int *) addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	*a |= mask;
+}
+
+inline void clear_bit(int nr, volatile void *addr)
+{
+	int	mask;
+	unsigned int *a = (unsigned int *) addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	*a &= ~mask;
+}
+
+struct fsg_dev;
+struct fsg_common;
+
+/* Data shared by all the FSG instances. */
+struct fsg_common {
+	struct usb_gadget	*gadget;
+	struct fsg_dev		*fsg, *new_fsg;
+
+	struct usb_ep		*ep0;		/* Copy of gadget->ep0 */
+	struct usb_request	*ep0req;	/* Copy of cdev->req */
+	unsigned int		ep0_req_tag;
+
+	struct fsg_buffhd	*next_buffhd_to_fill;
+	struct fsg_buffhd	*next_buffhd_to_drain;
+	struct fsg_buffhd	buffhds[FSG_NUM_BUFFERS];
+
+	int			cmnd_size;
+	u8			cmnd[MAX_COMMAND_SIZE];
+
+	unsigned int		nluns;
+	unsigned int		lun;
+	struct fsg_lun          luns[FSG_MAX_LUNS];
+
+	unsigned int		bulk_out_maxpacket;
+	enum fsg_state		state;		/* For exception handling */
+	unsigned int		exception_req_tag;
+
+	enum data_direction	data_dir;
+	u32			data_size;
+	u32			data_size_from_cmnd;
+	u32			tag;
+	u32			residue;
+	u32			usb_amount_left;
+
+	unsigned int		can_stall:1;
+	unsigned int		free_storage_on_release:1;
+	unsigned int		phase_error:1;
+	unsigned int		short_packet_received:1;
+	unsigned int		bad_lun_okay:1;
+	unsigned int		running:1;
+
+	int			thread_wakeup_needed;
+	struct completion	thread_notifier;
+	struct task_struct	*thread_task;
+
+	/* Callback functions. */
+	const struct fsg_operations	*ops;
+	/* Gadget's private data. */
+	void			*private_data;
+
+	const char *vendor_name;		/*  8 characters or less */
+	const char *product_name;		/* 16 characters or less */
+	u16 release;
+
+	/* Vendor (8 chars), product (16 chars), release (4
+	 * hexadecimal digits) and NUL byte */
+	char inquiry_string[8 + 16 + 4 + 1];
+
+	struct kref		ref;
+};
+
+struct fsg_config {
+	unsigned nluns;
+	struct fsg_lun_config {
+		const char *filename;
+		char ro;
+		char removable;
+		char cdrom;
+		char nofua;
+	} luns[FSG_MAX_LUNS];
+
+	/* Callback functions. */
+	const struct fsg_operations     *ops;
+	/* Gadget's private data. */
+	void			*private_data;
+
+	const char *vendor_name;		/*  8 characters or less */
+	const char *product_name;		/* 16 characters or less */
+
+	char			can_stall;
+};
+
+struct fsg_dev {
+	struct usb_function	function;
+	struct usb_gadget	*gadget;	/* Copy of cdev->gadget */
+	struct fsg_common	*common;
+
+	u16			interface_number;
+
+	unsigned int		bulk_in_enabled:1;
+	unsigned int		bulk_out_enabled:1;
+
+	unsigned long		atomic_bitflags;
+#define IGNORE_BULK_OUT		0
+
+	struct usb_ep		*bulk_in;
+	struct usb_ep		*bulk_out;
+};
+
+
+static inline int __fsg_is_set(struct fsg_common *common,
+			       const char *func, unsigned line)
+{
+	if (common->fsg)
+		return 1;
+	ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
+	WARN_ON(1);
+	return 0;
+}
+
+#define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
+
+
+static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
+{
+	return container_of(f, struct fsg_dev, function);
+}
+
+
+typedef void (*fsg_routine_t)(struct fsg_dev *);
+
+static int exception_in_progress(struct fsg_common *common)
+{
+	return common->state > FSG_STATE_IDLE;
+}
+
+/* Make bulk-out requests be divisible by the maxpacket size */
+static void set_bulk_out_req_length(struct fsg_common *common,
+		struct fsg_buffhd *bh, unsigned int length)
+{
+	unsigned int	rem;
+
+	bh->bulk_out_intended_length = length;
+	rem = length % common->bulk_out_maxpacket;
+	if (rem > 0)
+		length += common->bulk_out_maxpacket - rem;
+	bh->outreq->length = length;
+}
+
+/*-------------------------------------------------------------------------*/
+
+struct ums_board_info			*ums_info;
+struct fsg_common *the_fsg_common;
+
+static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
+{
+	const char	*name;
+
+	if (ep == fsg->bulk_in)
+		name = "bulk-in";
+	else if (ep == fsg->bulk_out)
+		name = "bulk-out";
+	else
+		name = ep->name;
+	DBG(fsg, "%s set halt\n", name);
+	return usb_ep_set_halt(ep);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* These routines may be called in process context or in_irq */
+
+/* Caller must hold fsg->lock */
+static void wakeup_thread(struct fsg_common *common)
+{
+	common->thread_wakeup_needed = 1;
+}
+
+static void raise_exception(struct fsg_common *common, enum fsg_state 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. */
+	if (common->state <= new_state) {
+		common->exception_req_tag = common->ep0_req_tag;
+		common->state = new_state;
+		common->thread_wakeup_needed = 1;
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int ep0_queue(struct fsg_common *common)
+{
+	int	rc;
+
+	rc = usb_ep_queue(common->ep0, common->ep0req, GFP_ATOMIC);
+	common->ep0->driver_data = common;
+	if (rc != 0 && rc != -ESHUTDOWN) {
+		/* We can't do much more than wait for a reset */
+		WARNING(common, "error in submission: %s --> %d\n",
+			common->ep0->name, rc);
+	}
+	return rc;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* 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_common	*common = ep->driver_data;
+	struct fsg_buffhd	*bh = req->context;
+
+	if (req->status || req->actual != req->length)
+		DBG(common, "%s --> %d, %u/%u\n", __func__,
+				req->status, req->actual, req->length);
+	if (req->status == -ECONNRESET)		/* Request was cancelled */
+		usb_ep_fifo_flush(ep);
+
+	/* Hold the lock while we update the request and buffer states */
+	bh->inreq_busy = 0;
+	bh->state = BUF_STATE_EMPTY;
+	wakeup_thread(common);
+}
+
+static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct fsg_common	*common = ep->driver_data;
+	struct fsg_buffhd	*bh = req->context;
+
+	dump_msg(common, "bulk-out", req->buf, req->actual);
+	if (req->status || req->actual != bh->bulk_out_intended_length)
+		DBG(common, "%s --> %d, %u/%u\n", __func__,
+				req->status, req->actual,
+				bh->bulk_out_intended_length);
+	if (req->status == -ECONNRESET)		/* Request was cancelled */
+		usb_ep_fifo_flush(ep);
+
+	/* Hold the lock while we update the request and buffer states */
+	bh->outreq_busy = 0;
+	bh->state = BUF_STATE_FULL;
+	wakeup_thread(common);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* Ep0 class-specific handlers.  These always run in_irq. */
+
+static int fsg_setup(struct usb_function *f,
+		const struct usb_ctrlrequest *ctrl)
+{
+	struct fsg_dev		*fsg = fsg_from_func(f);
+	struct usb_request	*req = fsg->common->ep0req;
+	u16			w_index = le16_to_cpu(ctrl->wIndex);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+	u16			w_length = le16_to_cpu(ctrl->wLength);
+
+	if (!fsg_is_set(fsg->common))
+		return -EOPNOTSUPP;
+
+	switch (ctrl->bRequest) {
+
+	case USB_BULK_RESET_REQUEST:
+		if (ctrl->bRequestType !=
+		    (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+			break;
+		if (w_index != fsg->interface_number || w_value != 0)
+			return -EDOM;
+
+		/* Raise an exception to stop the current operation
+		 * and reinitialize our state. */
+		DBG(fsg, "bulk reset request\n");
+		raise_exception(fsg->common, FSG_STATE_RESET);
+		return DELAYED_STATUS;
+
+	case USB_BULK_GET_MAX_LUN_REQUEST:
+		if (ctrl->bRequestType !=
+		    (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+			break;
+		if (w_index != fsg->interface_number || w_value != 0)
+			return -EDOM;
+		VDBG(fsg, "get max LUN\n");
+		*(u8 *) req->buf = fsg->common->nluns - 1;
+
+		/* Respond with data/status */
+		req->length = min((u16)1, w_length);
+		return ep0_queue(fsg->common);
+	}
+
+	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 -EOPNOTSUPP;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* 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;
+
+	if (ep == fsg->bulk_in)
+		dump_msg(fsg, "bulk-in", req->buf, req->length);
+
+	*pbusy = 1;
+	*state = BUF_STATE_BUSY;
+	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))
+			WARNING(fsg, "error in submission: %s --> %d\n",
+					ep->name, rc);
+	}
+}
+
+#define START_TRANSFER_OR(common, ep_name, req, pbusy, state)		\
+	if (fsg_is_set(common))						\
+		start_transfer((common)->fsg, (common)->fsg->ep_name,	\
+			       req, pbusy, state);			\
+	else
+
+#define START_TRANSFER(common, ep_name, req, pbusy, state)		\
+	START_TRANSFER_OR(common, ep_name, req, pbusy, state) (void)0
+
+static void busy_indicator(void)
+{
+	static int state;
+
+	switch (state) {
+	case 0:
+		puts("\r|"); break;
+	case 1:
+		puts("\r/"); break;
+	case 2:
+		puts("\r-"); break;
+	case 3:
+		puts("\r\\"); break;
+	case 4:
+		puts("\r|"); break;
+	case 5:
+		puts("\r/"); break;
+	case 6:
+		puts("\r-"); break;
+	case 7:
+		puts("\r\\"); break;
+	default:
+		state = 0;
+	}
+	if (state++ == 8)
+		state = 0;
+}
+
+static int sleep_thread(struct fsg_common *common)
+{
+	int	rc = 0;
+	int i = 0, k = 0;
+
+	/* Wait until a signal arrives or we are woken up */
+	for (;;) {
+		if (common->thread_wakeup_needed)
+			break;
+
+		if (++i == 50000) {
+			busy_indicator();
+			i = 0;
+			k++;
+		}
+
+		usb_gadget_handle_interrupts();
+	}
+	common->thread_wakeup_needed = 0;
+	return rc;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int do_read(struct fsg_common *common)
+{
+	struct fsg_lun		*curlun = &common->luns[common->lun];
+	u32			lba;
+	struct fsg_buffhd	*bh;
+	int			rc;
+	u32			amount_left;
+	loff_t			file_offset;
+	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 (common->cmnd[0] == SC_READ_6)
+		lba = get_unaligned_be24(&common->cmnd[1]);
+	else {
+		lba = get_unaligned_be32(&common->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 ((common->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 = common->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(amount_left, FSG_BUFLEN);
+		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 = common->next_buffhd_to_fill;
+		while (bh->state != BUF_STATE_EMPTY) {
+			rc = sleep_thread(common);
+			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->info_valid = 1;
+			bh->inreq->length = 0;
+			bh->state = BUF_STATE_FULL;
+			break;
+		}
+
+		/* Perform the read */
+		nread = 0;
+		rc = ums_info->read_sector(&(ums_info->ums_dev),
+					   file_offset / SECTOR_SIZE,
+					   amount / SECTOR_SIZE,
+					   (char __user *)bh->buf);
+		if (rc)
+			return -EIO;
+		nread = amount;
+
+		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+				(unsigned long long) file_offset,
+				(int) nread);
+
+		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;
+		common->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->info_valid = 1;
+			break;
+		}
+
+		if (amount_left == 0)
+			break;		/* No more left to read */
+
+		/* Send this buffer and go read some more */
+		bh->inreq->zero = 0;
+		START_TRANSFER_OR(common, bulk_in, bh->inreq,
+			       &bh->inreq_busy, &bh->state)
+			/* Don't know what to do if
+			 * common->fsg is NULL */
+			return -EIO;
+		common->next_buffhd_to_fill = bh->next;
+	}
+
+	return -EIO;		/* No default reply */
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int do_write(struct fsg_common *common)
+{
+	struct fsg_lun		*curlun = &common->luns[common->lun];
+	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;
+	unsigned int		amount;
+	unsigned int		partial_page;
+	ssize_t			nwritten;
+	int			rc;
+
+	if (curlun->ro) {
+		curlun->sense_data = SS_WRITE_PROTECTED;
+		return -EINVAL;
+	}
+
+	/* Get the starting Logical Block Address and check that it's
+	 * not too big */
+	if (common->cmnd[0] == SC_WRITE_6)
+		lba = get_unaligned_be24(&common->cmnd[1]);
+	else {
+		lba = get_unaligned_be32(&common->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 (common->cmnd[1] & ~0x18) {
+			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;
+	}
+
+	/* Carry out the file writes */
+	get_some_more = 1;
+	file_offset = usb_offset = ((loff_t) lba) << 9;
+	amount_left_to_req = common->data_size_from_cmnd;
+	amount_left_to_write = common->data_size_from_cmnd;
+
+	while (amount_left_to_write > 0) {
+
+		/* Queue a request for more data from the host */
+		bh = common->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, FSG_BUFLEN);
+			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->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;
+			common->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 = amount;
+			bh->bulk_out_intended_length = amount;
+			bh->outreq->short_not_ok = 1;
+			START_TRANSFER_OR(common, bulk_out, bh->outreq,
+					  &bh->outreq_busy, &bh->state)
+				/* Don't know what to do if
+				 * common->fsg is NULL */
+				return -EIO;
+			common->next_buffhd_to_fill = bh->next;
+			continue;
+		}
+
+		/* Write the received data to the backing file */
+		bh = common->next_buffhd_to_drain;
+		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
+			break;			/* We stopped early */
+		if (bh->state == BUF_STATE_FULL) {
+			common->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->info_valid = 1;
+				break;
+			}
+
+			amount = bh->outreq->actual;
+
+			/* Perform the write */
+			rc = ums_info->write_sector(&(ums_info->ums_dev),
+					       file_offset / SECTOR_SIZE,
+					       amount / SECTOR_SIZE,
+					       (char __user *)bh->buf);
+			if (rc)
+				return -EIO;
+			nwritten = amount;
+
+			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
+					(unsigned long long) file_offset,
+					(int) nwritten);
+
+			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;
+			common->residue -= nwritten;
+
+			/* If an error occurred, report it and its position */
+			if (nwritten < amount) {
+				curlun->sense_data = SS_WRITE_ERROR;
+				curlun->info_valid = 1;
+				break;
+			}
+
+			/* Did the host decide to stop early? */
+			if (bh->outreq->actual != bh->outreq->length) {
+				common->short_packet_received = 1;
+				break;
+			}
+			continue;
+		}
+
+		/* Wait for something to happen */
+		rc = sleep_thread(common);
+		if (rc)
+			return rc;
+	}
+
+	return -EIO;		/* No default reply */
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int do_synchronize_cache(struct fsg_common *common)
+{
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int do_verify(struct fsg_common *common)
+{
+	struct fsg_lun		*curlun = &common->luns[common->lun];
+	u32			lba;
+	u32			verification_length;
+	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
+	loff_t			file_offset;
+	u32			amount_left;
+	unsigned int		amount;
+	ssize_t			nread;
+	int			rc;
+
+	/* Get the starting Logical Block Address and check that it's
+	 * not too big */
+	lba = get_unaligned_be32(&common->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 (common->cmnd[1] & ~0x10) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	verification_length = get_unaligned_be16(&common->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 */
+
+	/* 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(amount_left, FSG_BUFLEN);
+		if (amount == 0) {
+			curlun->sense_data =
+					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+			curlun->info_valid = 1;
+			break;
+		}
+
+		/* Perform the read */
+		nread = 0;
+		rc = ums_info->read_sector(&(ums_info->ums_dev),
+					   file_offset / SECTOR_SIZE,
+					   amount / SECTOR_SIZE,
+					   (char __user *)bh->buf);
+		if (rc)
+			return -EIO;
+		nread = amount;
+
+		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+				(unsigned long long) file_offset,
+				(int) nread);
+		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->info_valid = 1;
+			break;
+		}
+		file_offset += nread;
+		amount_left -= nread;
+	}
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int do_inquiry(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun *curlun = &common->luns[common->lun];
+	static const char vendor_id[] = "Linux   ";
+	u8	*buf = (u8 *) bh->buf;
+
+	if (!curlun) {		/* Unsupported LUNs are okay */
+		common->bad_lun_okay = 1;
+		memset(buf, 0, 36);
+		buf[0] = 0x7f;		/* Unsupported, no device-type */
+		buf[4] = 31;		/* Additional length */
+		return 36;
+	}
+
+	memset(buf, 0, 8);
+	buf[0] = TYPE_DISK;
+	buf[2] = 2;		/* ANSI SCSI level 2 */
+	buf[3] = 2;		/* SCSI-2 INQUIRY data format */
+	buf[4] = 31;		/* Additional length */
+				/* No special options */
+	sprintf((char *) (buf + 8), "%-8s%-16s%04x", (char*) vendor_id ,
+			ums_info->name, (u16) 0xffff);
+
+	return 36;
+}
+
+
+static int do_request_sense(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	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 */
+		common->bad_lun_okay = 1;
+		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+		sdinfo = 0;
+		valid = 0;
+	} else {
+		sd = curlun->sense_data;
+		valid = curlun->info_valid << 7;
+		curlun->sense_data = SS_NO_SENSE;
+		curlun->info_valid = 0;
+	}
+
+	memset(buf, 0, 18);
+	buf[0] = valid | 0x70;			/* Valid, current error */
+	buf[2] = SK(sd);
+	put_unaligned_be32(sdinfo, &buf[3]);	/* 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_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	u32		lba = get_unaligned_be32(&common->cmnd[2]);
+	int		pmi = common->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_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
+						/* Max logical block */
+	put_unaligned_be32(512, &buf[4]);	/* Block length */
+	return 8;
+}
+
+static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	int		msf = common->cmnd[1] & 0x02;
+	u32		lba = get_unaligned_be32(&common->cmnd[2]);
+	u8		*buf = (u8 *) bh->buf;
+
+	if (common->cmnd[1] & ~0x02) {		/* Mask away MSF */
+		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;
+	}
+
+	memset(buf, 0, 8);
+	buf[0] = 0x01;		/* 2048 bytes of user data, rest is EC */
+	store_cdrom_address(&buf[4], msf, lba);
+	return 8;
+}
+
+
+static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	int		msf = common->cmnd[1] & 0x02;
+	int		start_track = common->cmnd[6];
+	u8		*buf = (u8 *) bh->buf;
+
+	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
+			start_track > 1) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	memset(buf, 0, 20);
+	buf[1] = (20-2);		/* TOC data length */
+	buf[2] = 1;			/* First track number */
+	buf[3] = 1;			/* Last track number */
+	buf[5] = 0x16;			/* Data track, copying allowed */
+	buf[6] = 0x01;			/* Only track is number 1 */
+	store_cdrom_address(&buf[8], msf, 0);
+
+	buf[13] = 0x16;			/* Lead-out track is data */
+	buf[14] = 0xAA;			/* Lead-out track number */
+	store_cdrom_address(&buf[16], msf, curlun->num_sectors);
+
+	return 20;
+}
+
+static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	int		mscmnd = common->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 ((common->cmnd[1] & ~0x08) != 0) {	/* Mask away DBD */
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+	pc = common->cmnd[2] >> 6;
+	page_code = common->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;		/* Should really be FSG_BUFLEN */
+	}
+
+	/* No block descriptors */
+
+	/* 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_unaligned_be16(0xffff, &buf[4]);
+					/* Don't disable prefetch */
+					/* Minimum prefetch = 0 */
+			put_unaligned_be16(0xffff, &buf[8]);
+					/* Maximum prefetch */
+			put_unaligned_be16(0xffff, &buf[10]);
+					/* Maximum prefetch ceiling */
+		}
+		buf += 12;
+	}
+
+	/* 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_unaligned_be16(len - 2, buf0);
+	return len;
+}
+
+
+static int do_start_stop(struct fsg_common *common)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+
+	if (!curlun) {
+		return -EINVAL;
+	} else if (!curlun->removable) {
+		curlun->sense_data = SS_INVALID_COMMAND;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int do_prevent_allow(struct fsg_common *common)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	int		prevent;
+
+	if (!curlun->removable) {
+		curlun->sense_data = SS_INVALID_COMMAND;
+		return -EINVAL;
+	}
+
+	prevent = common->cmnd[4] & 0x01;
+	if ((common->cmnd[4] & ~0x01) != 0) {	/* Mask away Prevent */
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+
+	if (curlun->prevent_medium_removal && !prevent)
+		fsg_lun_fsync_sub(curlun);
+	curlun->prevent_medium_removal = prevent;
+	return 0;
+}
+
+
+static int do_read_format_capacities(struct fsg_common *common,
+			struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+	u8		*buf = (u8 *) bh->buf;
+
+	buf[0] = buf[1] = buf[2] = 0;
+	buf[3] = 8;	/* Only the Current/Maximum Capacity Descriptor */
+	buf += 4;
+
+	put_unaligned_be32(curlun->num_sectors, &buf[0]);
+						/* Number of blocks */
+	put_unaligned_be32(512, &buf[4]);	/* Block length */
+	buf[4] = 0x02;				/* Current capacity */
+	return 12;
+}
+
+
+static int do_mode_select(struct fsg_common *common, struct fsg_buffhd *bh)
+{
+	struct fsg_lun	*curlun = &common->luns[common->lun];
+
+	/* We don't support MODE SELECT */
+	if (curlun)
+		curlun->sense_data = SS_INVALID_COMMAND;
+	return -EINVAL;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
+{
+	int	rc;
+
+	rc = fsg_set_halt(fsg, fsg->bulk_in);
+	if (rc == -EAGAIN)
+		VDBG(fsg, "delayed bulk-in endpoint halt\n");
+	while (rc != 0) {
+		if (rc != -EAGAIN) {
+			WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
+			rc = 0;
+			break;
+		}
+
+		rc = usb_ep_set_halt(fsg->bulk_in);
+	}
+	return rc;
+}
+
+static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
+{
+	int	rc;
+
+	DBG(fsg, "bulk-in set wedge\n");
+	rc = 0; /* usb_ep_set_wedge(fsg->bulk_in); */
+	if (rc == -EAGAIN)
+		VDBG(fsg, "delayed bulk-in endpoint wedge\n");
+	while (rc != 0) {
+		if (rc != -EAGAIN) {
+			WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
+			rc = 0;
+			break;
+		}
+	}
+	return rc;
+}
+
+static int pad_with_zeros(struct fsg_dev *fsg)
+{
+	struct fsg_buffhd	*bh = fsg->common->next_buffhd_to_fill;
+	u32			nkeep = bh->inreq->length;
+	u32			nsend;
+	int			rc;
+
+	bh->state = BUF_STATE_EMPTY;		/* For the first iteration */
+	fsg->common->usb_amount_left = nkeep + fsg->common->residue;
+	while (fsg->common->usb_amount_left > 0) {
+
+		/* Wait for the next buffer to be free */
+		while (bh->state != BUF_STATE_EMPTY) {
+			rc = sleep_thread(fsg->common);
+			if (rc)
+				return rc;
+		}
+
+		nsend = min(fsg->common->usb_amount_left, FSG_BUFLEN);
+		memset(bh->buf + nkeep, 0, nsend - nkeep);
+		bh->inreq->length = nsend;
+		bh->inreq->zero = 0;
+		start_transfer(fsg, fsg->bulk_in, bh->inreq,
+				&bh->inreq_busy, &bh->state);
+		bh = fsg->common->next_buffhd_to_fill = bh->next;
+		fsg->common->usb_amount_left -= nsend;
+		nkeep = 0;
+	}
+	return 0;
+}
+
+static int throw_away_data(struct fsg_common *common)
+{
+	struct fsg_buffhd	*bh;
+	u32			amount;
+	int			rc;
+
+	for (bh = common->next_buffhd_to_drain;
+	     bh->state != BUF_STATE_EMPTY || common->usb_amount_left > 0;
+	     bh = common->next_buffhd_to_drain) {
+
+		/* Throw away the data in a filled buffer */
+		if (bh->state == BUF_STATE_FULL) {
+			bh->state = BUF_STATE_EMPTY;
+			common->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(common,
+						FSG_STATE_ABORT_BULK_OUT);
+				return -EINTR;
+			}
+			continue;
+		}
+
+		/* Try to submit another request if we need one */
+		bh = common->next_buffhd_to_fill;
+		if (bh->state == BUF_STATE_EMPTY
+		 && common->usb_amount_left > 0) {
+			amount = min(common->usb_amount_left, FSG_BUFLEN);
+
+			/* amount is always divisible by 512, hence by
+			 * the bulk-out maxpacket size */
+			bh->outreq->length = amount;
+			bh->bulk_out_intended_length = amount;
+			bh->outreq->short_not_ok = 1;
+			START_TRANSFER_OR(common, bulk_out, bh->outreq,
+					  &bh->outreq_busy, &bh->state)
+				/* Don't know what to do if
+				 * common->fsg is NULL */
+				return -EIO;
+			common->next_buffhd_to_fill = bh->next;
+			common->usb_amount_left -= amount;
+			continue;
+		}
+
+		/* Otherwise wait for something to happen */
+		rc = sleep_thread(common);
+		if (rc)
+			return rc;
+	}
+	return 0;
+}
+
+
+static int finish_reply(struct fsg_common *common)
+{
+	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
+	int			rc = 0;
+
+	switch (common->data_dir) {
+	case DATA_DIR_NONE:
+		break;			/* Nothing to send */
+
+	/* If we don't know whether the host wants to read or write,
+	 * this must be CB or CBI with an unknown command.  We mustn't
+	 * try to send or receive any data.  So stall both bulk pipes
+	 * if we can and wait for a reset. */
+	case DATA_DIR_UNKNOWN:
+		if (!common->can_stall) {
+			/* Nothing */
+		} else if (fsg_is_set(common)) {
+			fsg_set_halt(common->fsg, common->fsg->bulk_out);
+			rc = halt_bulk_in_endpoint(common->fsg);
+		} else {
+			/* Don't know what to do if common->fsg is NULL */
+			rc = -EIO;
+		}
+		break;
+
+	/* All but the last buffer of data must have already been sent */
+	case DATA_DIR_TO_HOST:
+		if (common->data_size == 0) {
+			/* Nothing to send */
+
+		/* If there's no residue, simply send the last buffer */
+		} else if (common->residue == 0) {
+			bh->inreq->zero = 0;
+			START_TRANSFER_OR(common, bulk_in, bh->inreq,
+					  &bh->inreq_busy, &bh->state)
+				return -EIO;
+			common->next_buffhd_to_fill = bh->next;
+
+		/* For Bulk-only, if we're allowed to stall then send the
+		 * short packet and halt the bulk-in endpoint.  If we can't
+		 * stall, pad out the remaining data with 0's. */
+		} else if (common->can_stall) {
+			bh->inreq->zero = 1;
+			START_TRANSFER_OR(common, bulk_in, bh->inreq,
+					  &bh->inreq_busy, &bh->state)
+				/* Don't know what to do if
+				 * common->fsg is NULL */
+				rc = -EIO;
+			common->next_buffhd_to_fill = bh->next;
+			if (common->fsg)
+				rc = halt_bulk_in_endpoint(common->fsg);
+		} else if (fsg_is_set(common)) {
+			rc = pad_with_zeros(common->fsg);
+		} else {
+			/* Don't know what to do if common->fsg is NULL */
+			rc = -EIO;
+		}
+		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 (common->residue == 0) {
+			/* Nothing to receive */
+
+		/* Did the host stop sending unexpectedly early? */
+		} else if (common->short_packet_received) {
+			raise_exception(common, 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
+		} else if (common->can_stall) {
+			if (fsg_is_set(common))
+				fsg_set_halt(common->fsg,
+					     common->fsg->bulk_out);
+			raise_exception(common, 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(common);
+		}
+		break;
+	}
+	return rc;
+}
+
+
+static int send_status(struct fsg_common *common)
+{
+	struct fsg_lun		*curlun = &common->luns[common->lun];
+	struct fsg_buffhd	*bh;
+	struct bulk_cs_wrap	*csw;
+	int			rc;
+	u8			status = USB_STATUS_PASS;
+	u32			sd, sdinfo = 0;
+
+	/* Wait for the next buffer to become available */
+	bh = common->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(common);
+		if (rc)
+			return rc;
+	}
+
+	if (curlun)
+		sd = curlun->sense_data;
+	else if (common->bad_lun_okay)
+		sd = SS_NO_SENSE;
+	else
+		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+
+	if (common->phase_error) {
+		DBG(common, "sending phase-error status\n");
+		status = USB_STATUS_PHASE_ERROR;
+		sd = SS_INVALID_COMMAND;
+	} else if (sd != SS_NO_SENSE) {
+		DBG(common, "sending command-failure status\n");
+		status = USB_STATUS_FAIL;
+		VDBG(common, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
+			"  info x%x\n",
+			SK(sd), ASC(sd), ASCQ(sd), sdinfo);
+	}
+
+	/* Store and send the Bulk-only CSW */
+	csw = (void *)bh->buf;
+
+	csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
+	csw->Tag = common->tag;
+	csw->Residue = cpu_to_le32(common->residue);
+	csw->Status = status;
+
+	bh->inreq->length = USB_BULK_CS_WRAP_LEN;
+	bh->inreq->zero = 0;
+	START_TRANSFER_OR(common, bulk_in, bh->inreq,
+			  &bh->inreq_busy, &bh->state)
+		/* Don't know what to do if common->fsg is NULL */
+		return -EIO;
+
+	common->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_common *common, int cmnd_size,
+		enum data_direction data_dir, unsigned int mask,
+		int needs_medium, const char *name)
+{
+	int			i;
+	int			lun = common->cmnd[1] >> 5;
+	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
+	char			hdlen[20];
+	struct fsg_lun		*curlun;
+
+	hdlen[0] = 0;
+	if (common->data_dir != DATA_DIR_UNKNOWN)
+		sprintf(hdlen, ", H%c=%u", dirletter[(int) common->data_dir],
+				common->data_size);
+	VDBG(common, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
+	     name, cmnd_size, dirletter[(int) data_dir],
+	     common->data_size_from_cmnd, common->cmnd_size, hdlen);
+
+	/* We can't reply at all until we know the correct data direction
+	 * and size. */
+	if (common->data_size_from_cmnd == 0)
+		data_dir = DATA_DIR_NONE;
+	if (common->data_size < common->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. */
+		common->data_size_from_cmnd = common->data_size;
+		common->phase_error = 1;
+	}
+	common->residue = common->data_size;
+	common->usb_amount_left = common->data_size;
+
+	/* Conflicting data directions is a phase error */
+	if (common->data_dir != data_dir
+	 && common->data_size_from_cmnd > 0) {
+		common->phase_error = 1;
+		return -EINVAL;
+	}
+
+	/* Verify the length of the command itself */
+	if (cmnd_size != common->cmnd_size) {
+
+		/* Special case workaround: There are plenty of buggy SCSI
+		 * implementations. Many have issues with cbw->Length
+		 * field passing a wrong command size. For those cases we
+		 * always try to work around the problem by using the length
+		 * sent by the host side provided it is at least as large
+		 * as the correct command length.
+		 * Examples of such cases would be MS-Windows, which issues
+		 * REQUEST SENSE with cbw->Length == 12 where it should
+		 * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
+		 * REQUEST SENSE with cbw->Length == 10 where it should
+		 * be 6 as well.
+		 */
+		if (cmnd_size <= common->cmnd_size) {
+			DBG(common, "%s is buggy! Expected length %d "
+			    "but we got %d\n", name,
+			    cmnd_size, common->cmnd_size);
+			cmnd_size = common->cmnd_size;
+		} else {
+			common->phase_error = 1;
+			return -EINVAL;
+		}
+	}
+
+	/* Check that the LUN values are consistent */
+	if (common->lun != lun)
+		DBG(common, "using LUN %d from CBW, not LUN %d from CDB\n",
+		    common->lun, lun);
+
+	/* Check the LUN */
+	if (common->lun >= 0 && common->lun < common->nluns) {
+		curlun = &common->luns[common->lun];
+		if (common->cmnd[0] != SC_REQUEST_SENSE) {
+			curlun->sense_data = SS_NO_SENSE;
+			curlun->info_valid = 0;
+		}
+	} else {
+		curlun = NULL;
+		common->bad_lun_okay = 0;
+
+		/* INQUIRY and REQUEST SENSE commands are explicitly allowed
+		 * to use unsupported LUNs; all others may not. */
+		if (common->cmnd[0] != SC_INQUIRY &&
+		    common->cmnd[0] != SC_REQUEST_SENSE) {
+			DBG(common, "unsupported LUN %d\n", common->lun);
+			return -EINVAL;
+		}
+	}
+#if 0
+	/* 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 &&
+			common->cmnd[0] != SC_INQUIRY &&
+			common->cmnd[0] != SC_REQUEST_SENSE) {
+		curlun->sense_data = curlun->unit_attention_data;
+		curlun->unit_attention_data = SS_NO_SENSE;
+		return -EINVAL;
+	}
+#endif
+	/* Check that only command bytes listed in the mask are non-zero */
+	common->cmnd[1] &= 0x1f;			/* Mask away the LUN */
+	for (i = 1; i < cmnd_size; ++i) {
+		if (common->cmnd[i] && !(mask & (1 << i))) {
+			if (curlun)
+				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+
+static int do_scsi_command(struct fsg_common *common)
+{
+	struct fsg_buffhd	*bh;
+	int			rc;
+	int			reply = -EINVAL;
+	int			i;
+	static char		unknown[16];
+	struct fsg_lun		*curlun = &common->luns[common->lun];
+
+	dump_cdb(common);
+
+	/* Wait for the next buffer to become available for data or status */
+	bh = common->next_buffhd_to_fill;
+	common->next_buffhd_to_drain = bh;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(common);
+		if (rc)
+			return rc;
+	}
+	common->phase_error = 0;
+	common->short_packet_received = 0;
+
+	down_read(&common->filesem);	/* We're using the backing file */
+	switch (common->cmnd[0]) {
+
+	case SC_INQUIRY:
+		common->data_size_from_cmnd = common->cmnd[4];
+		reply = check_command(common, 6, DATA_DIR_TO_HOST,
+				      (1<<4), 0,
+				      "INQUIRY");
+		if (reply == 0)
+			reply = do_inquiry(common, bh);
+		break;
+
+	case SC_MODE_SELECT_6:
+		common->data_size_from_cmnd = common->cmnd[4];
+		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
+				      (1<<1) | (1<<4), 0,
+				      "MODE SELECT(6)");
+		if (reply == 0)
+			reply = do_mode_select(common, bh);
+		break;
+
+	case SC_MODE_SELECT_10:
+		common->data_size_from_cmnd =
+			get_unaligned_be16(&common->cmnd[7]);
+		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
+				      (1<<1) | (3<<7), 0,
+				      "MODE SELECT(10)");
+		if (reply == 0)
+			reply = do_mode_select(common, bh);
+		break;
+
+	case SC_MODE_SENSE_6:
+		common->data_size_from_cmnd = common->cmnd[4];
+		reply = check_command(common, 6, DATA_DIR_TO_HOST,
+				      (1<<1) | (1<<2) | (1<<4), 0,
+				      "MODE SENSE(6)");
+		if (reply == 0)
+			reply = do_mode_sense(common, bh);
+		break;
+
+	case SC_MODE_SENSE_10:
+		common->data_size_from_cmnd =
+			get_unaligned_be16(&common->cmnd[7]);
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (1<<1) | (1<<2) | (3<<7), 0,
+				      "MODE SENSE(10)");
+		if (reply == 0)
+			reply = do_mode_sense(common, bh);
+		break;
+
+	case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
+		common->data_size_from_cmnd = 0;
+		reply = check_command(common, 6, DATA_DIR_NONE,
+				      (1<<4), 0,
+				      "PREVENT-ALLOW MEDIUM REMOVAL");
+		if (reply == 0)
+			reply = do_prevent_allow(common);
+		break;
+
+	case SC_READ_6:
+		i = common->cmnd[4];
+		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+		reply = check_command(common, 6, DATA_DIR_TO_HOST,
+				      (7<<1) | (1<<4), 1,
+				      "READ(6)");
+		if (reply == 0)
+			reply = do_read(common);
+		break;
+
+	case SC_READ_10:
+		common->data_size_from_cmnd =
+				get_unaligned_be16(&common->cmnd[7]) << 9;
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (1<<1) | (0xf<<2) | (3<<7), 1,
+				      "READ(10)");
+		if (reply == 0)
+			reply = do_read(common);
+		break;
+
+	case SC_READ_12:
+		common->data_size_from_cmnd =
+				get_unaligned_be32(&common->cmnd[6]) << 9;
+		reply = check_command(common, 12, DATA_DIR_TO_HOST,
+				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
+				      "READ(12)");
+		if (reply == 0)
+			reply = do_read(common);
+		break;
+
+	case SC_READ_CAPACITY:
+		common->data_size_from_cmnd = 8;
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (0xf<<2) | (1<<8), 1,
+				      "READ CAPACITY");
+		if (reply == 0)
+			reply = do_read_capacity(common, bh);
+		break;
+
+	case SC_READ_HEADER:
+		if (!common->luns[common->lun].cdrom)
+			goto unknown_cmnd;
+		common->data_size_from_cmnd =
+			get_unaligned_be16(&common->cmnd[7]);
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (3<<7) | (0x1f<<1), 1,
+				      "READ HEADER");
+		if (reply == 0)
+			reply = do_read_header(common, bh);
+		break;
+
+	case SC_READ_TOC:
+		if (!common->luns[common->lun].cdrom)
+			goto unknown_cmnd;
+		common->data_size_from_cmnd =
+			get_unaligned_be16(&common->cmnd[7]);
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (7<<6) | (1<<1), 1,
+				      "READ TOC");
+		if (reply == 0)
+			reply = do_read_toc(common, bh);
+		break;
+
+	case SC_READ_FORMAT_CAPACITIES:
+		common->data_size_from_cmnd =
+			get_unaligned_be16(&common->cmnd[7]);
+		reply = check_command(common, 10, DATA_DIR_TO_HOST,
+				      (3<<7), 1,
+				      "READ FORMAT CAPACITIES");
+		if (reply == 0)
+			reply = do_read_format_capacities(common, bh);
+		break;
+
+	case SC_REQUEST_SENSE:
+		common->data_size_from_cmnd = common->cmnd[4];
+		reply = check_command(common, 6, DATA_DIR_TO_HOST,
+				      (1<<4), 0,
+				      "REQUEST SENSE");
+		if (reply == 0)
+			reply = do_request_sense(common, bh);
+		break;
+
+	case SC_START_STOP_UNIT:
+		common->data_size_from_cmnd = 0;
+		reply = check_command(common, 6, DATA_DIR_NONE,
+				      (1<<1) | (1<<4), 0,
+				      "START-STOP UNIT");
+		if (reply == 0)
+			reply = do_start_stop(common);
+		break;
+
+	case SC_SYNCHRONIZE_CACHE:
+		common->data_size_from_cmnd = 0;
+		reply = check_command(common, 10, DATA_DIR_NONE,
+				      (0xf<<2) | (3<<7), 1,
+				      "SYNCHRONIZE CACHE");
+		if (reply == 0)
+			reply = do_synchronize_cache(common);
+		break;
+
+	case SC_TEST_UNIT_READY:
+		common->data_size_from_cmnd = 0;
+		reply = check_command(common, 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:
+		common->data_size_from_cmnd = 0;
+		reply = check_command(common, 10, DATA_DIR_NONE,
+				      (1<<1) | (0xf<<2) | (3<<7), 1,
+				      "VERIFY");
+		if (reply == 0)
+			reply = do_verify(common);
+		break;
+
+	case SC_WRITE_6:
+		i = common->cmnd[4];
+		common->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
+				      (7<<1) | (1<<4), 1,
+				      "WRITE(6)");
+		if (reply == 0)
+			reply = do_write(common);
+		break;
+
+	case SC_WRITE_10:
+		common->data_size_from_cmnd =
+				get_unaligned_be16(&common->cmnd[7]) << 9;
+		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
+				      (1<<1) | (0xf<<2) | (3<<7), 1,
+				      "WRITE(10)");
+		if (reply == 0)
+			reply = do_write(common);
+		break;
+
+	case SC_WRITE_12:
+		common->data_size_from_cmnd =
+				get_unaligned_be32(&common->cmnd[6]) << 9;
+		reply = check_command(common, 12, DATA_DIR_FROM_HOST,
+				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
+				      "WRITE(12)");
+		if (reply == 0)
+			reply = do_write(common);
+		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:
+unknown_cmnd:
+		common->data_size_from_cmnd = 0;
+		sprintf(unknown, "Unknown x%02x", common->cmnd[0]);
+		reply = check_command(common, common->cmnd_size,
+				      DATA_DIR_UNKNOWN, 0xff, 0, unknown);
+		if (reply == 0) {
+			curlun->sense_data = SS_INVALID_COMMAND;
+			reply = -EINVAL;
+		}
+		break;
+	}
+	up_read(&common->filesem);
+
+	if (reply == -EINTR)
+		return -EINTR;
+
+	/* Set up the single reply buffer for finish_reply() */
+	if (reply == -EINVAL)
+		reply = 0;		/* Error reply length */
+	if (reply >= 0 && common->data_dir == DATA_DIR_TO_HOST) {
+		reply = min((u32) reply, common->data_size_from_cmnd);
+		bh->inreq->length = reply;
+		bh->state = BUF_STATE_FULL;
+		common->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 fsg_bulk_cb_wrap	*cbw = req->buf;
+	struct fsg_common	*common = fsg->common;
+
+	/* Was this a real packet?  Should it be ignored? */
+	if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
+		return -EINVAL;
+
+	/* Is the CBW valid? */
+	if (req->actual != USB_BULK_CB_WRAP_LEN ||
+			cbw->Signature != cpu_to_le32(
+				USB_BULK_CB_SIG)) {
+		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
+				req->actual,
+				le32_to_cpu(cbw->Signature));
+
+		/* The Bulk-only spec says we MUST stall the IN endpoint
+		 * (6.6.1), so it's unavoidable.  It also says we must
+		 * retain this state until the next reset, but there's
+		 * no way to tell the controller driver it should ignore
+		 * Clear-Feature(HALT) requests.
+		 *
+		 * We aren't required to halt the OUT endpoint; instead
+		 * we can simply accept and discard any data received
+		 * until the next reset. */
+		wedge_bulk_in_endpoint(fsg);
+		set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+		return -EINVAL;
+	}
+
+	/* Is the CBW meaningful? */
+	if (cbw->Lun >= FSG_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);
+
+		/* We can do anything we want here, so let's stall the
+		 * bulk pipes if we are allowed to. */
+		if (common->can_stall) {
+			fsg_set_halt(fsg, fsg->bulk_out);
+			halt_bulk_in_endpoint(fsg);
+		}
+		return -EINVAL;
+	}
+
+	/* Save the command for later */
+	common->cmnd_size = cbw->Length;
+	memcpy(common->cmnd, cbw->CDB, common->cmnd_size);
+	if (cbw->Flags & USB_BULK_IN_FLAG)
+		common->data_dir = DATA_DIR_TO_HOST;
+	else
+		common->data_dir = DATA_DIR_FROM_HOST;
+	common->data_size = le32_to_cpu(cbw->DataTransferLength);
+	if (common->data_size == 0)
+		common->data_dir = DATA_DIR_NONE;
+	common->lun = cbw->Lun;
+	common->tag = cbw->Tag;
+	return 0;
+}
+
+
+static int get_next_command(struct fsg_common *common)
+{
+	struct fsg_buffhd	*bh;
+	int			rc = 0;
+
+	/* Wait for the next buffer to become available */
+	bh = common->next_buffhd_to_fill;
+	while (bh->state != BUF_STATE_EMPTY) {
+		rc = sleep_thread(common);
+		if (rc)
+			return rc;
+	}
+
+	/* Queue a request to read a Bulk-only CBW */
+	set_bulk_out_req_length(common, bh, USB_BULK_CB_WRAP_LEN);
+	bh->outreq->short_not_ok = 1;
+	START_TRANSFER_OR(common, bulk_out, bh->outreq,
+			  &bh->outreq_busy, &bh->state)
+		/* Don't know what to do if common->fsg is NULL */
+		return -EIO;
+
+	/* 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(common);
+		if (rc)
+			return rc;
+	}
+
+	rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;
+	bh->state = BUF_STATE_EMPTY;
+
+	return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int enable_endpoint(struct fsg_common *common, struct usb_ep *ep,
+		const struct usb_endpoint_descriptor *d)
+{
+	int	rc;
+
+	ep->driver_data = common;
+	rc = usb_ep_enable(ep, d);
+	if (rc)
+		ERROR(common, "can't enable %s, result %d\n", ep->name, rc);
+	return rc;
+}
+
+static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
+		struct usb_request **preq)
+{
+	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
+	if (*preq)
+		return 0;
+	ERROR(common, "can't allocate request for %s\n", ep->name);
+	return -ENOMEM;
+}
+
+/* Reset interface setting and re-init endpoint state (toggle etc). */
+static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
+{
+	const struct usb_endpoint_descriptor *d;
+	struct fsg_dev *fsg;
+	int i, rc = 0;
+
+	if (common->running)
+		DBG(common, "reset interface\n");
+
+reset:
+	/* Deallocate the requests */
+	if (common->fsg) {
+		fsg = common->fsg;
+
+		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+			struct fsg_buffhd *bh = &common->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) {
+			usb_ep_disable(fsg->bulk_in);
+			fsg->bulk_in_enabled = 0;
+		}
+		if (fsg->bulk_out_enabled) {
+			usb_ep_disable(fsg->bulk_out);
+			fsg->bulk_out_enabled = 0;
+		}
+
+		common->fsg = NULL;
+		/* wake_up(&common->fsg_wait); */
+	}
+
+	common->running = 0;
+	if (!new_fsg || rc)
+		return rc;
+
+	common->fsg = new_fsg;
+	fsg = common->fsg;
+
+	/* Enable the endpoints */
+	d = fsg_ep_desc(common->gadget,
+			&fsg_fs_bulk_in_desc, &fsg_hs_bulk_in_desc);
+	rc = enable_endpoint(common, fsg->bulk_in, d);
+	if (rc)
+		goto reset;
+	fsg->bulk_in_enabled = 1;
+
+	d = fsg_ep_desc(common->gadget,
+			&fsg_fs_bulk_out_desc, &fsg_hs_bulk_out_desc);
+	rc = enable_endpoint(common, fsg->bulk_out, d);
+	if (rc)
+		goto reset;
+	fsg->bulk_out_enabled = 1;
+	common->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
+	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+
+	/* Allocate the requests */
+	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+		struct fsg_buffhd	*bh = &common->buffhds[i];
+
+		rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
+		if (rc)
+			goto reset;
+		rc = alloc_request(common, fsg->bulk_out, &bh->outreq);
+		if (rc)
+			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;
+	}
+
+	common->running = 1;
+
+	return rc;
+}
+
+
+/****************************** ALT CONFIGS ******************************/
+
+
+static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct fsg_dev *fsg = fsg_from_func(f);
+	fsg->common->new_fsg = fsg;
+	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
+	return 0;
+}
+
+static void fsg_disable(struct usb_function *f)
+{
+	struct fsg_dev *fsg = fsg_from_func(f);
+	fsg->common->new_fsg = NULL;
+	raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void handle_exception(struct fsg_common *common)
+{
+	int			i;
+	struct fsg_buffhd	*bh;
+	enum fsg_state		old_state;
+	struct fsg_lun		*curlun;
+	unsigned int		exception_req_tag;
+
+	/* Cancel all the pending transfers */
+	if (common->fsg) {
+		for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+			bh = &common->buffhds[i];
+			if (bh->inreq_busy)
+				usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
+			if (bh->outreq_busy)
+				usb_ep_dequeue(common->fsg->bulk_out,
+					       bh->outreq);
+		}
+
+		/* Wait until everything is idle */
+		for (;;) {
+			int num_active = 0;
+			for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+				bh = &common->buffhds[i];
+				num_active += bh->inreq_busy + bh->outreq_busy;
+			}
+			if (num_active == 0)
+				break;
+			if (sleep_thread(common))
+				return;
+		}
+
+		/* Clear out the controller's fifos */
+		if (common->fsg->bulk_in_enabled)
+			usb_ep_fifo_flush(common->fsg->bulk_in);
+		if (common->fsg->bulk_out_enabled)
+			usb_ep_fifo_flush(common->fsg->bulk_out);
+	}
+
+	/* Reset the I/O buffer states and pointers, the SCSI
+	 * state, and the exception.  Then invoke the handler. */
+
+	for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+		bh = &common->buffhds[i];
+		bh->state = BUF_STATE_EMPTY;
+	}
+	common->next_buffhd_to_fill = &common->buffhds[0];
+	common->next_buffhd_to_drain = &common->buffhds[0];
+	exception_req_tag = common->exception_req_tag;
+	old_state = common->state;
+
+	if (old_state == FSG_STATE_ABORT_BULK_OUT)
+		common->state = FSG_STATE_STATUS_PHASE;
+	else {
+		for (i = 0; i < common->nluns; ++i) {
+			curlun = &common->luns[i];
+			curlun->sense_data = SS_NO_SENSE;
+			curlun->info_valid = 0;
+		}
+		common->state = FSG_STATE_IDLE;
+	}
+
+	/* Carry out any extra actions required for the exception */
+	switch (old_state) {
+	case FSG_STATE_ABORT_BULK_OUT:
+		send_status(common);
+
+		if (common->state == FSG_STATE_STATUS_PHASE)
+			common->state = FSG_STATE_IDLE;
+		break;
+
+	case FSG_STATE_RESET:
+		/* In case we were forced against our will to halt a
+		 * bulk endpoint, clear the halt now.  (The SuperH UDC
+		 * requires this.) */
+		if (!fsg_is_set(common))
+			break;
+		if (test_and_clear_bit(IGNORE_BULK_OUT,
+				       &common->fsg->atomic_bitflags))
+			usb_ep_clear_halt(common->fsg->bulk_in);
+
+		if (common->ep0_req_tag == exception_req_tag)
+			ep0_queue(common);	/* Complete the status stage */
+
+		break;
+
+	case FSG_STATE_CONFIG_CHANGE:
+		do_set_interface(common, common->new_fsg);
+		break;
+
+	case FSG_STATE_EXIT:
+	case FSG_STATE_TERMINATED:
+		do_set_interface(common, NULL);		/* Free resources */
+		common->state = FSG_STATE_TERMINATED;	/* Stop the thread */
+		break;
+
+	case FSG_STATE_INTERFACE_CHANGE:
+	case FSG_STATE_DISCONNECT:
+	case FSG_STATE_COMMAND_PHASE:
+	case FSG_STATE_DATA_PHASE:
+	case FSG_STATE_STATUS_PHASE:
+	case FSG_STATE_IDLE:
+		break;
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+int fsg_main_thread(void *common_)
+{
+	struct fsg_common	*common = the_fsg_common;
+	/* The main loop */
+	do {
+		if (exception_in_progress(common)) {
+			handle_exception(common);
+			continue;
+		}
+
+		if (!common->running) {
+			sleep_thread(common);
+			continue;
+		}
+
+		if (get_next_command(common))
+			continue;
+
+		if (!exception_in_progress(common))
+			common->state = FSG_STATE_DATA_PHASE;
+
+		if (do_scsi_command(common) || finish_reply(common))
+			continue;
+
+		if (!exception_in_progress(common))
+			common->state = FSG_STATE_STATUS_PHASE;
+
+		if (send_status(common))
+			continue;
+
+		if (!exception_in_progress(common))
+			common->state = FSG_STATE_IDLE;
+	} while (0);
+
+	common->thread_task = NULL;
+
+	return 0;
+}
+
+static void fsg_common_release(struct kref *ref);
+
+static struct fsg_common *fsg_common_init(struct fsg_common *common,
+					  struct usb_composite_dev *cdev)
+{
+	struct usb_gadget *gadget = cdev->gadget;
+	struct fsg_buffhd *bh;
+	struct fsg_lun *curlun;
+	int nluns, i, rc;
+
+	/* Find out how many LUNs there should be */
+	nluns = 1;
+	if (nluns < 1 || nluns > FSG_MAX_LUNS) {
+		printf("invalid number of LUNs: %u\n", nluns);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* Allocate? */
+	if (!common) {
+		common = calloc(sizeof *common, 1);
+		if (!common)
+			return ERR_PTR(-ENOMEM);
+		common->free_storage_on_release = 1;
+	} else {
+		memset(common, 0, sizeof common);
+		common->free_storage_on_release = 0;
+	}
+
+	common->ops = NULL;
+	common->private_data = NULL;
+
+	common->gadget = gadget;
+	common->ep0 = gadget->ep0;
+	common->ep0req = cdev->req;
+
+	/* Maybe allocate device-global string IDs, and patch descriptors */
+	if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
+		rc = usb_string_id(cdev);
+		if (unlikely(rc < 0))
+			goto error_release;
+		fsg_strings[FSG_STRING_INTERFACE].id = rc;
+		fsg_intf_desc.iInterface = rc;
+	}
+
+	/* Create the LUNs, open their backing files, and register the
+	 * LUN devices in sysfs. */
+	curlun = calloc(nluns, sizeof *curlun);
+	if (!curlun) {
+		rc = -ENOMEM;
+		goto error_release;
+	}
+	common->nluns = nluns;
+
+	for (i = 0; i < nluns; i++) {
+		common->luns[i].removable = 1;
+
+		rc = fsg_lun_open(&common->luns[i], "");
+		if (rc)
+			goto error_luns;
+	}
+	common->lun = 0;
+
+	/* Data buffers cyclic list */
+	bh = common->buffhds;
+
+	i = FSG_NUM_BUFFERS;
+	goto buffhds_first_it;
+	do {
+		bh->next = bh + 1;
+		++bh;
+buffhds_first_it:
+		bh->inreq_busy = 0;
+		bh->outreq_busy = 0;
+		bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
+		if (unlikely(!bh->buf)) {
+			rc = -ENOMEM;
+			goto error_release;
+		}
+	} while (--i);
+	bh->next = common->buffhds;
+
+	snprintf(common->inquiry_string, sizeof common->inquiry_string,
+		 "%-8s%-16s%04x",
+		 "Linux   ",
+		 "File-Store Gadget",
+		 0xffff);
+
+	/* Some peripheral controllers are known not to be able to
+	 * halt bulk endpoints correctly.  If one of them is present,
+	 * disable stalls.
+	 */
+
+	/* Tell the thread to start working */
+	common->thread_task =
+		kthread_create(fsg_main_thread, common,
+			       OR(cfg->thread_name, "file-storage"));
+	if (IS_ERR(common->thread_task)) {
+		rc = PTR_ERR(common->thread_task);
+		goto error_release;
+	}
+
+#undef OR
+	/* Information */
+	INFO(common, FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
+	INFO(common, "Number of LUNs=%d\n", common->nluns);
+
+	return common;
+
+error_luns:
+	common->nluns = i + 1;
+error_release:
+	common->state = FSG_STATE_TERMINATED;	/* The thread is dead */
+	/* Call fsg_common_release() directly, ref might be not
+	 * initialised */
+	fsg_common_release(&common->ref);
+	return ERR_PTR(rc);
+}
+
+static void fsg_common_release(struct kref *ref)
+{
+	struct fsg_common *common = container_of(ref, struct fsg_common, ref);
+
+	/* If the thread isn't already dead, tell it to exit now */
+	if (common->state != FSG_STATE_TERMINATED) {
+		raise_exception(common, FSG_STATE_EXIT);
+		wait_for_completion(&common->thread_notifier);
+	}
+
+	if (likely(common->luns)) {
+		struct fsg_lun *lun = common->luns;
+		unsigned i = common->nluns;
+
+		/* In error recovery common->nluns may be zero. */
+		for (; i; --i, ++lun)
+			fsg_lun_close(lun);
+
+		kfree(common->luns);
+	}
+
+	{
+		struct fsg_buffhd *bh = common->buffhds;
+		unsigned i = FSG_NUM_BUFFERS;
+		do {
+			kfree(bh->buf);
+		} while (++bh, --i);
+	}
+
+	if (common->free_storage_on_release)
+		kfree(common);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/**
+ * usb_copy_descriptors - copy a vector of USB descriptors
+ * @src: null-terminated vector to copy
+ * Context: initialization code, which may sleep
+ *
+ * This makes a copy of a vector of USB descriptors.  Its primary use
+ * is to support usb_function objects which can have multiple copies,
+ * each needing different descriptors.  Functions may have static
+ * tables of descriptors, which are used as templates and customized
+ * with identifiers (for interfaces, strings, endpoints, and more)
+ * as needed by a given function instance.
+ */
+struct usb_descriptor_header **
+usb_copy_descriptors(struct usb_descriptor_header **src)
+{
+	struct usb_descriptor_header **tmp;
+	unsigned bytes;
+	unsigned n_desc;
+	void *mem;
+	struct usb_descriptor_header **ret;
+
+	/* count descriptors and their sizes; then add vector size */
+	for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
+		bytes += (*tmp)->bLength;
+	bytes += (n_desc + 1) * sizeof(*tmp);
+
+	mem = kmalloc(bytes, GFP_KERNEL);
+	if (!mem)
+		return NULL;
+
+	/* fill in pointers starting at "tmp",
+	 * to descriptors copied starting at "mem";
+	 * and return "ret"
+	 */
+	tmp = mem;
+	ret = mem;
+	mem += (n_desc + 1) * sizeof(*tmp);
+	while (*src) {
+		memcpy(mem, *src, (*src)->bLength);
+		*tmp = mem;
+		tmp++;
+		mem += (*src)->bLength;
+		src++;
+	}
+	*tmp = NULL;
+
+	return ret;
+}
+
+
+
+static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct fsg_dev		*fsg = fsg_from_func(f);
+
+	DBG(fsg, "unbind\n");
+	if (fsg->common->fsg == fsg) {
+		fsg->common->new_fsg = NULL;
+		raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE);
+	}
+
+	free(fsg->function.descriptors);
+	free(fsg->function.hs_descriptors);
+	kfree(fsg);
+}
+
+static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct fsg_dev		*fsg = fsg_from_func(f);
+	struct usb_gadget	*gadget = c->cdev->gadget;
+	int			i;
+	struct usb_ep		*ep;
+	fsg->gadget = gadget;
+
+	/* New interface */
+	i = usb_interface_id(c, f);
+	if (i < 0)
+		return i;
+	fsg_intf_desc.bInterfaceNumber = i;
+	fsg->interface_number = i;
+
+	/* Find all the endpoints we will use */
+	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_in_desc);
+	if (!ep)
+		goto autoconf_fail;
+	ep->driver_data = fsg->common;	/* claim the endpoint */
+	fsg->bulk_in = ep;
+
+	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_out_desc);
+	if (!ep)
+		goto autoconf_fail;
+	ep->driver_data = fsg->common;	/* claim the endpoint */
+	fsg->bulk_out = ep;
+
+	/* Copy descriptors */
+	f->descriptors = usb_copy_descriptors(fsg_fs_function);
+	if (unlikely(!f->descriptors))
+		return -ENOMEM;
+
+	if (gadget_is_dualspeed(gadget)) {
+		/* Assume endpoint addresses are the same for both speeds */
+		fsg_hs_bulk_in_desc.bEndpointAddress =
+			fsg_fs_bulk_in_desc.bEndpointAddress;
+		fsg_hs_bulk_out_desc.bEndpointAddress =
+			fsg_fs_bulk_out_desc.bEndpointAddress;
+		f->hs_descriptors = usb_copy_descriptors(fsg_hs_function);
+		if (unlikely(!f->hs_descriptors)) {
+			free(f->descriptors);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+
+autoconf_fail:
+	ERROR(fsg, "unable to autoconfigure all endpoints\n");
+	return -ENOTSUPP;
+}
+
+
+/****************************** ADD FUNCTION ******************************/
+
+static struct usb_gadget_strings *fsg_strings_array[] = {
+	&fsg_stringtab,
+	NULL,
+};
+
+static int fsg_bind_config(struct usb_composite_dev *cdev,
+			   struct usb_configuration *c,
+			   struct fsg_common *common)
+{
+	struct fsg_dev *fsg;
+	int rc;
+
+	fsg = calloc(1, sizeof *fsg);
+	if (!fsg)
+		return -ENOMEM;
+	fsg->function.name        = FSG_DRIVER_DESC;
+	fsg->function.strings     = fsg_strings_array;
+	fsg->function.bind        = fsg_bind;
+	fsg->function.unbind      = fsg_unbind;
+	fsg->function.setup       = fsg_setup;
+	fsg->function.set_alt     = fsg_set_alt;
+	fsg->function.disable     = fsg_disable;
+
+	fsg->common               = common;
+	common->fsg               = fsg;
+	/* Our caller holds a reference to common structure so we
+	 * don't have to be worry about it being freed until we return
+	 * from this function.  So instead of incrementing counter now
+	 * and decrement in error recovery we increment it only when
+	 * call to usb_add_function() was successful. */
+
+	rc = usb_add_function(c, &fsg->function);
+
+	if (rc)
+		kfree(fsg);
+
+	return rc;
+}
+
+int fsg_add(struct usb_configuration *c)
+{
+	struct fsg_common *fsg_common;
+
+	fsg_common = fsg_common_init(NULL, c->cdev);
+
+	fsg_common->vendor_name = 0;
+	fsg_common->product_name = 0;
+	fsg_common->release = 0xffff;
+
+	fsg_common->ops = NULL;
+	fsg_common->private_data = NULL;
+
+	the_fsg_common = fsg_common;
+
+	return fsg_bind_config(c->cdev, c, fsg_common);
+}
+
+int fsg_init(struct ums_board_info *ums)
+{
+	ums_info = ums;
+
+	return 0;
+}