Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1357 insertions, 0 deletions

diff --git a/drivers/usb/gadget/zero.c b/drivers/usb/gadget/zero.c
new file mode 100644
index 00000000000..6e49432071a
--- /dev/null
+++ b/drivers/usb/gadget/zero.c
@@ -0,0 +1,1357 @@
+/*
+ * zero.c -- Gadget Zero, for USB development
+ *
+ * Copyright (C) 2003-2004 David Brownell
+ * 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.
+ */
+
+
+/*
+ * Gadget Zero only needs two bulk endpoints, and is an example of how you
+ * can write a hardware-agnostic gadget driver running inside a USB device.
+ *
+ * Hardware details are visible (see CONFIG_USB_ZERO_* below) but don't
+ * affect most of the driver.
+ *
+ * Use it with the Linux host/master side "usbtest" driver to get a basic
+ * functional test of your device-side usb stack, or with "usb-skeleton".
+ *
+ * It supports two similar configurations.  One sinks whatever the usb host
+ * writes, and in return sources zeroes.  The other loops whatever the host
+ * writes back, so the host can read it.  Module options include:
+ *
+ *   buflen=N		default N=4096, buffer size used
+ *   qlen=N		default N=32, how many buffers in the loopback queue
+ *   loopdefault	default false, list loopback config first
+ *
+ * Many drivers will only have one configuration, letting them be much
+ * simpler if they also don't support high speed operation (like this
+ * driver does).
+ */
+
+#define DEBUG 1
+// #define VERBOSE
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/timer.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/utsname.h>
+#include <linux/device.h>
+#include <linux/moduleparam.h>
+
+#include <asm/byteorder.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/system.h>
+#include <asm/unaligned.h>
+
+#include <linux/usb_ch9.h>
+#include <linux/usb_gadget.h>
+
+#include "gadget_chips.h"
+
+
+/*-------------------------------------------------------------------------*/
+
+#define DRIVER_VERSION		"St Patrick's Day 2004"
+
+static const char shortname [] = "zero";
+static const char longname [] = "Gadget Zero";
+
+static const char source_sink [] = "source and sink data";
+static const char loopback [] = "loop input to output";
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * driver assumes self-powered hardware, and
+ * has no way for users to trigger remote wakeup.
+ *
+ * this version autoconfigures as much as possible,
+ * which is reasonable for most "bulk-only" drivers.
+ */
+static const char *EP_IN_NAME;		/* source */
+static const char *EP_OUT_NAME;		/* sink */
+
+/*-------------------------------------------------------------------------*/
+
+/* big enough to hold our biggest descriptor */
+#define USB_BUFSIZ	256
+
+struct zero_dev {
+	spinlock_t		lock;
+	struct usb_gadget	*gadget;
+	struct usb_request	*req;		/* for control responses */
+
+	/* when configured, we have one of two configs:
+	 * - source data (in to host) and sink it (out from host)
+	 * - or loop it back (out from host back in to host)
+	 */
+	u8			config;
+	struct usb_ep		*in_ep, *out_ep;
+
+	/* autoresume timer */
+	struct timer_list	resume;
+};
+
+#define xprintk(d,level,fmt,args...) \
+	dev_printk(level , &(d)->gadget->dev , fmt , ## args)
+
+#ifdef DEBUG
+#define DBG(dev,fmt,args...) \
+	xprintk(dev , KERN_DEBUG , fmt , ## args)
+#else
+#define DBG(dev,fmt,args...) \
+	do { } while (0)
+#endif /* DEBUG */
+
+#ifdef VERBOSE
+#define VDBG	DBG
+#else
+#define VDBG(dev,fmt,args...) \
+	do { } while (0)
+#endif /* VERBOSE */
+
+#define ERROR(dev,fmt,args...) \
+	xprintk(dev , KERN_ERR , fmt , ## args)
+#define WARN(dev,fmt,args...) \
+	xprintk(dev , KERN_WARNING , fmt , ## args)
+#define INFO(dev,fmt,args...) \
+	xprintk(dev , KERN_INFO , fmt , ## args)
+
+/*-------------------------------------------------------------------------*/
+
+static unsigned buflen = 4096;
+static unsigned qlen = 32;
+static unsigned pattern = 0;
+
+module_param (buflen, uint, S_IRUGO|S_IWUSR);
+module_param (qlen, uint, S_IRUGO|S_IWUSR);
+module_param (pattern, uint, S_IRUGO|S_IWUSR);
+
+/*
+ * if it's nonzero, autoresume says how many seconds to wait
+ * before trying to wake up the host after suspend.
+ */
+static unsigned autoresume = 0;
+module_param (autoresume, uint, 0);
+
+/*
+ * Normally the "loopback" configuration is second (index 1) so
+ * it's not the default.  Here's where to change that order, to
+ * work better with hosts where config changes are problematic.
+ * Or controllers (like superh) that only support one config.
+ */
+static int loopdefault = 0;
+
+module_param (loopdefault, bool, S_IRUGO|S_IWUSR);
+
+/*-------------------------------------------------------------------------*/
+
+/* Thanks to NetChip Technologies for donating this product ID.
+ *
+ * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
+ * Instead:  allocate your own, using normal USB-IF procedures.
+ */
+#ifndef	CONFIG_USB_ZERO_HNPTEST
+#define DRIVER_VENDOR_NUM	0x0525		/* NetChip */
+#define DRIVER_PRODUCT_NUM	0xa4a0		/* Linux-USB "Gadget Zero" */
+#else
+#define DRIVER_VENDOR_NUM	0x1a0a		/* OTG test device IDs */
+#define DRIVER_PRODUCT_NUM	0xbadd
+#endif
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * DESCRIPTORS ... most are static, but strings and (full)
+ * configuration descriptors are built on demand.
+ */
+
+#define STRING_MANUFACTURER		25
+#define STRING_PRODUCT			42
+#define STRING_SERIAL			101
+#define STRING_SOURCE_SINK		250
+#define STRING_LOOPBACK			251
+
+/*
+ * This device advertises two configurations; these numbers work
+ * on a pxa250 as well as more flexible hardware.
+ */
+#define	CONFIG_SOURCE_SINK	3
+#define	CONFIG_LOOPBACK		2
+
+static struct usb_device_descriptor
+device_desc = {
+	.bLength =		sizeof device_desc,
+	.bDescriptorType =	USB_DT_DEVICE,
+
+	.bcdUSB =		__constant_cpu_to_le16 (0x0200),
+	.bDeviceClass =		USB_CLASS_VENDOR_SPEC,
+
+	.idVendor =		__constant_cpu_to_le16 (DRIVER_VENDOR_NUM),
+	.idProduct =		__constant_cpu_to_le16 (DRIVER_PRODUCT_NUM),
+	.iManufacturer =	STRING_MANUFACTURER,
+	.iProduct =		STRING_PRODUCT,
+	.iSerialNumber =	STRING_SERIAL,
+	.bNumConfigurations =	2,
+};
+
+static struct usb_config_descriptor
+source_sink_config = {
+	.bLength =		sizeof source_sink_config,
+	.bDescriptorType =	USB_DT_CONFIG,
+
+	/* compute wTotalLength on the fly */
+	.bNumInterfaces =	1,
+	.bConfigurationValue =	CONFIG_SOURCE_SINK,
+	.iConfiguration =	STRING_SOURCE_SINK,
+	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
+	.bMaxPower =		1,	/* self-powered */
+};
+
+static struct usb_config_descriptor
+loopback_config = {
+	.bLength =		sizeof loopback_config,
+	.bDescriptorType =	USB_DT_CONFIG,
+
+	/* compute wTotalLength on the fly */
+	.bNumInterfaces =	1,
+	.bConfigurationValue =	CONFIG_LOOPBACK,
+	.iConfiguration =	STRING_LOOPBACK,
+	.bmAttributes =		USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
+	.bMaxPower =		1,	/* self-powered */
+};
+
+static struct usb_otg_descriptor
+otg_descriptor = {
+	.bLength =		sizeof otg_descriptor,
+	.bDescriptorType =	USB_DT_OTG,
+
+	.bmAttributes =		USB_OTG_SRP,
+};
+
+/* one interface in each configuration */
+
+static const struct usb_interface_descriptor
+source_sink_intf = {
+	.bLength =		sizeof source_sink_intf,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	.iInterface =		STRING_SOURCE_SINK,
+};
+
+static const struct usb_interface_descriptor
+loopback_intf = {
+	.bLength =		sizeof loopback_intf,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	.iInterface =		STRING_LOOPBACK,
+};
+
+/* two full speed bulk endpoints; their use is config-dependent */
+
+static struct usb_endpoint_descriptor
+fs_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor
+fs_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static const struct usb_descriptor_header *fs_source_sink_function [] = {
+	(struct usb_descriptor_header *) &otg_descriptor,
+	(struct usb_descriptor_header *) &source_sink_intf,
+	(struct usb_descriptor_header *) &fs_sink_desc,
+	(struct usb_descriptor_header *) &fs_source_desc,
+	NULL,
+};
+
+static const struct usb_descriptor_header *fs_loopback_function [] = {
+	(struct usb_descriptor_header *) &otg_descriptor,
+	(struct usb_descriptor_header *) &loopback_intf,
+	(struct usb_descriptor_header *) &fs_sink_desc,
+	(struct usb_descriptor_header *) &fs_source_desc,
+	NULL,
+};
+
+#ifdef	CONFIG_USB_GADGET_DUALSPEED
+
+/*
+ * usb 2.0 devices need to expose both high speed and full speed
+ * descriptors, unless they only run at full speed.
+ *
+ * that means alternate endpoint descriptors (bigger packets)
+ * and a "device qualifier" ... plus more construction options
+ * for the config descriptor.
+ */
+
+static struct usb_endpoint_descriptor
+hs_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16 (512),
+};
+
+static struct usb_endpoint_descriptor
+hs_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	__constant_cpu_to_le16 (512),
+};
+
+static struct usb_qualifier_descriptor
+dev_qualifier = {
+	.bLength =		sizeof dev_qualifier,
+	.bDescriptorType =	USB_DT_DEVICE_QUALIFIER,
+
+	.bcdUSB =		__constant_cpu_to_le16 (0x0200),
+	.bDeviceClass =		USB_CLASS_VENDOR_SPEC,
+
+	.bNumConfigurations =	2,
+};
+
+static const struct usb_descriptor_header *hs_source_sink_function [] = {
+	(struct usb_descriptor_header *) &otg_descriptor,
+	(struct usb_descriptor_header *) &source_sink_intf,
+	(struct usb_descriptor_header *) &hs_source_desc,
+	(struct usb_descriptor_header *) &hs_sink_desc,
+	NULL,
+};
+
+static const struct usb_descriptor_header *hs_loopback_function [] = {
+	(struct usb_descriptor_header *) &otg_descriptor,
+	(struct usb_descriptor_header *) &loopback_intf,
+	(struct usb_descriptor_header *) &hs_source_desc,
+	(struct usb_descriptor_header *) &hs_sink_desc,
+	NULL,
+};
+
+/* maxpacket and other transfer characteristics vary by speed. */
+#define ep_desc(g,hs,fs) (((g)->speed==USB_SPEED_HIGH)?(hs):(fs))
+
+#else
+
+/* if there's no high speed support, maxpacket doesn't change. */
+#define ep_desc(g,hs,fs) fs
+
+#endif	/* !CONFIG_USB_GADGET_DUALSPEED */
+
+static char				manufacturer [50];
+static char				serial [40];
+
+/* static strings, in UTF-8 */
+static struct usb_string		strings [] = {
+	{ STRING_MANUFACTURER, manufacturer, },
+	{ STRING_PRODUCT, longname, },
+	{ STRING_SERIAL, serial, },
+	{ STRING_LOOPBACK, loopback, },
+	{ STRING_SOURCE_SINK, source_sink, },
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings	stringtab = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings,
+};
+
+/*
+ * config descriptors are also handcrafted.  these must agree with code
+ * that sets configurations, and with code managing interfaces and their
+ * altsettings.  other complexity may come from:
+ *
+ *  - high speed support, including "other speed config" rules
+ *  - multiple configurations
+ *  - interfaces with alternate settings
+ *  - embedded class or vendor-specific descriptors
+ *
+ * this handles high speed, and has a second config that could as easily
+ * have been an alternate interface setting (on most hardware).
+ *
+ * NOTE:  to demonstrate (and test) more USB capabilities, this driver
+ * should include an altsetting to test interrupt transfers, including
+ * high bandwidth modes at high speed.  (Maybe work like Intel's test
+ * device?)
+ */
+static int
+config_buf (struct usb_gadget *gadget,
+		u8 *buf, u8 type, unsigned index)
+{
+	int				is_source_sink;
+	int				len;
+	const struct usb_descriptor_header **function;
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+	int				hs = (gadget->speed == USB_SPEED_HIGH);
+#endif
+
+	/* two configurations will always be index 0 and index 1 */
+	if (index > 1)
+		return -EINVAL;
+	is_source_sink = loopdefault ? (index == 1) : (index == 0);
+
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+	if (type == USB_DT_OTHER_SPEED_CONFIG)
+		hs = !hs;
+	if (hs)
+		function = is_source_sink
+			? hs_source_sink_function
+			: hs_loopback_function;
+	else
+#endif
+		function = is_source_sink
+			? fs_source_sink_function
+			: fs_loopback_function;
+
+	/* for now, don't advertise srp-only devices */
+	if (!gadget->is_otg)
+		function++;
+
+	len = usb_gadget_config_buf (is_source_sink
+					? &source_sink_config
+					: &loopback_config,
+			buf, USB_BUFSIZ, function);
+	if (len < 0)
+		return len;
+	((struct usb_config_descriptor *) buf)->bDescriptorType = type;
+	return len;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_request *
+alloc_ep_req (struct usb_ep *ep, unsigned length)
+{
+	struct usb_request	*req;
+
+	req = usb_ep_alloc_request (ep, GFP_ATOMIC);
+	if (req) {
+		req->length = length;
+		req->buf = usb_ep_alloc_buffer (ep, length,
+				&req->dma, GFP_ATOMIC);
+		if (!req->buf) {
+			usb_ep_free_request (ep, req);
+			req = NULL;
+		}
+	}
+	return req;
+}
+
+static void free_ep_req (struct usb_ep *ep, struct usb_request *req)
+{
+	if (req->buf)
+		usb_ep_free_buffer (ep, req->buf, req->dma, req->length);
+	usb_ep_free_request (ep, req);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* optionally require specific source/sink data patterns  */
+
+static int
+check_read_data (
+	struct zero_dev		*dev,
+	struct usb_ep		*ep,
+	struct usb_request	*req
+)
+{
+	unsigned	i;
+	u8		*buf = req->buf;
+
+	for (i = 0; i < req->actual; i++, buf++) {
+		switch (pattern) {
+		/* all-zeroes has no synchronization issues */
+		case 0:
+			if (*buf == 0)
+				continue;
+			break;
+		/* mod63 stays in sync with short-terminated transfers,
+		 * or otherwise when host and gadget agree on how large
+		 * each usb transfer request should be.  resync is done
+		 * with set_interface or set_config.
+		 */
+		case 1:
+			if (*buf == (u8)(i % 63))
+				continue;
+			break;
+		}
+		ERROR (dev, "bad OUT byte, buf [%d] = %d\n", i, *buf);
+		usb_ep_set_halt (ep);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void
+reinit_write_data (
+	struct zero_dev		*dev,
+	struct usb_ep		*ep,
+	struct usb_request	*req
+)
+{
+	unsigned	i;
+	u8		*buf = req->buf;
+
+	switch (pattern) {
+	case 0:
+		memset (req->buf, 0, req->length);
+		break;
+	case 1:
+		for  (i = 0; i < req->length; i++)
+			*buf++ = (u8) (i % 63);
+		break;
+	}
+}
+
+/* if there is only one request in the queue, there'll always be an
+ * irq delay between end of one request and start of the next.
+ * that prevents using hardware dma queues.
+ */
+static void source_sink_complete (struct usb_ep *ep, struct usb_request *req)
+{
+	struct zero_dev	*dev = ep->driver_data;
+	int		status = req->status;
+
+	switch (status) {
+
+	case 0: 			/* normal completion? */
+		if (ep == dev->out_ep)
+			check_read_data (dev, ep, req);
+		else
+			reinit_write_data (dev, ep, req);
+		break;
+
+	/* this endpoint is normally active while we're configured */
+	case -ECONNABORTED: 		/* hardware forced ep reset */
+	case -ECONNRESET:		/* request dequeued */
+	case -ESHUTDOWN:		/* disconnect from host */
+		VDBG (dev, "%s gone (%d), %d/%d\n", ep->name, status,
+				req->actual, req->length);
+		if (ep == dev->out_ep)
+			check_read_data (dev, ep, req);
+		free_ep_req (ep, req);
+		return;
+
+	case -EOVERFLOW:		/* buffer overrun on read means that
+					 * we didn't provide a big enough
+					 * buffer.
+					 */
+	default:
+#if 1
+		DBG (dev, "%s complete --> %d, %d/%d\n", ep->name,
+				status, req->actual, req->length);
+#endif
+	case -EREMOTEIO:		/* short read */
+		break;
+	}
+
+	status = usb_ep_queue (ep, req, GFP_ATOMIC);
+	if (status) {
+		ERROR (dev, "kill %s:  resubmit %d bytes --> %d\n",
+				ep->name, req->length, status);
+		usb_ep_set_halt (ep);
+		/* FIXME recover later ... somehow */
+	}
+}
+
+static struct usb_request *
+source_sink_start_ep (struct usb_ep *ep, int gfp_flags)
+{
+	struct usb_request	*req;
+	int			status;
+
+	req = alloc_ep_req (ep, buflen);
+	if (!req)
+		return NULL;
+
+	memset (req->buf, 0, req->length);
+	req->complete = source_sink_complete;
+
+	if (strcmp (ep->name, EP_IN_NAME) == 0)
+		reinit_write_data (ep->driver_data, ep, req);
+
+	status = usb_ep_queue (ep, req, gfp_flags);
+	if (status) {
+		struct zero_dev	*dev = ep->driver_data;
+
+		ERROR (dev, "start %s --> %d\n", ep->name, status);
+		free_ep_req (ep, req);
+		req = NULL;
+	}
+
+	return req;
+}
+
+static int
+set_source_sink_config (struct zero_dev *dev, int gfp_flags)
+{
+	int			result = 0;
+	struct usb_ep		*ep;
+	struct usb_gadget	*gadget = dev->gadget;
+
+	gadget_for_each_ep (ep, gadget) {
+		const struct usb_endpoint_descriptor	*d;
+
+		/* one endpoint writes (sources) zeroes in (to the host) */
+		if (strcmp (ep->name, EP_IN_NAME) == 0) {
+			d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
+			result = usb_ep_enable (ep, d);
+			if (result == 0) {
+				ep->driver_data = dev;
+				if (source_sink_start_ep (ep, gfp_flags) != 0) {
+					dev->in_ep = ep;
+					continue;
+				}
+				usb_ep_disable (ep);
+				result = -EIO;
+			}
+
+		/* one endpoint reads (sinks) anything out (from the host) */
+		} else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
+			d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
+			result = usb_ep_enable (ep, d);
+			if (result == 0) {
+				ep->driver_data = dev;
+				if (source_sink_start_ep (ep, gfp_flags) != 0) {
+					dev->out_ep = ep;
+					continue;
+				}
+				usb_ep_disable (ep);
+				result = -EIO;
+			}
+
+		/* ignore any other endpoints */
+		} else
+			continue;
+
+		/* stop on error */
+		ERROR (dev, "can't start %s, result %d\n", ep->name, result);
+		break;
+	}
+	if (result == 0)
+		DBG (dev, "buflen %d\n", buflen);
+
+	/* caller is responsible for cleanup on error */
+	return result;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void loopback_complete (struct usb_ep *ep, struct usb_request *req)
+{
+	struct zero_dev	*dev = ep->driver_data;
+	int		status = req->status;
+
+	switch (status) {
+
+	case 0: 			/* normal completion? */
+		if (ep == dev->out_ep) {
+			/* loop this OUT packet back IN to the host */
+			req->zero = (req->actual < req->length);
+			req->length = req->actual;
+			status = usb_ep_queue (dev->in_ep, req, GFP_ATOMIC);
+			if (status == 0)
+				return;
+
+			/* "should never get here" */
+			ERROR (dev, "can't loop %s to %s: %d\n",
+				ep->name, dev->in_ep->name,
+				status);
+		}
+
+		/* queue the buffer for some later OUT packet */
+		req->length = buflen;
+		status = usb_ep_queue (dev->out_ep, req, GFP_ATOMIC);
+		if (status == 0)
+			return;
+
+		/* "should never get here" */
+		/* FALLTHROUGH */
+
+	default:
+		ERROR (dev, "%s loop complete --> %d, %d/%d\n", ep->name,
+				status, req->actual, req->length);
+		/* FALLTHROUGH */
+
+	/* NOTE:  since this driver doesn't maintain an explicit record
+	 * of requests it submitted (just maintains qlen count), we
+	 * rely on the hardware driver to clean up on disconnect or
+	 * endpoint disable.
+	 */
+	case -ECONNABORTED: 		/* hardware forced ep reset */
+	case -ECONNRESET:		/* request dequeued */
+	case -ESHUTDOWN:		/* disconnect from host */
+		free_ep_req (ep, req);
+		return;
+	}
+}
+
+static int
+set_loopback_config (struct zero_dev *dev, int gfp_flags)
+{
+	int			result = 0;
+	struct usb_ep		*ep;
+	struct usb_gadget	*gadget = dev->gadget;
+
+	gadget_for_each_ep (ep, gadget) {
+		const struct usb_endpoint_descriptor	*d;
+
+		/* one endpoint writes data back IN to the host */
+		if (strcmp (ep->name, EP_IN_NAME) == 0) {
+			d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
+			result = usb_ep_enable (ep, d);
+			if (result == 0) {
+				ep->driver_data = dev;
+				dev->in_ep = ep;
+				continue;
+			}
+
+		/* one endpoint just reads OUT packets */
+		} else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
+			d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
+			result = usb_ep_enable (ep, d);
+			if (result == 0) {
+				ep->driver_data = dev;
+				dev->out_ep = ep;
+				continue;
+			}
+
+		/* ignore any other endpoints */
+		} else
+			continue;
+
+		/* stop on error */
+		ERROR (dev, "can't enable %s, result %d\n", ep->name, result);
+		break;
+	}
+
+	/* allocate a bunch of read buffers and queue them all at once.
+	 * we buffer at most 'qlen' transfers; fewer if any need more
+	 * than 'buflen' bytes each.
+	 */
+	if (result == 0) {
+		struct usb_request	*req;
+		unsigned		i;
+
+		ep = dev->out_ep;
+		for (i = 0; i < qlen && result == 0; i++) {
+			req = alloc_ep_req (ep, buflen);
+			if (req) {
+				req->complete = loopback_complete;
+				result = usb_ep_queue (ep, req, GFP_ATOMIC);
+				if (result)
+					DBG (dev, "%s queue req --> %d\n",
+							ep->name, result);
+			} else
+				result = -ENOMEM;
+		}
+	}
+	if (result == 0)
+		DBG (dev, "qlen %d, buflen %d\n", qlen, buflen);
+
+	/* caller is responsible for cleanup on error */
+	return result;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void zero_reset_config (struct zero_dev *dev)
+{
+	if (dev->config == 0)
+		return;
+
+	DBG (dev, "reset config\n");
+
+	/* just disable endpoints, forcing completion of pending i/o.
+	 * all our completion handlers free their requests in this case.
+	 */
+	if (dev->in_ep) {
+		usb_ep_disable (dev->in_ep);
+		dev->in_ep = NULL;
+	}
+	if (dev->out_ep) {
+		usb_ep_disable (dev->out_ep);
+		dev->out_ep = NULL;
+	}
+	dev->config = 0;
+	del_timer (&dev->resume);
+}
+
+/* change our operational config.  this code must agree with the code
+ * that returns config descriptors, and altsetting code.
+ *
+ * it's also responsible for power management interactions. some
+ * configurations might not work with our current power sources.
+ *
+ * note that some device controller hardware will constrain what this
+ * code can do, perhaps by disallowing more than one configuration or
+ * by limiting configuration choices (like the pxa2xx).
+ */
+static int
+zero_set_config (struct zero_dev *dev, unsigned number, int gfp_flags)
+{
+	int			result = 0;
+	struct usb_gadget	*gadget = dev->gadget;
+
+	if (number == dev->config)
+		return 0;
+
+	if (gadget_is_sa1100 (gadget) && dev->config) {
+		/* tx fifo is full, but we can't clear it...*/
+		INFO (dev, "can't change configurations\n");
+		return -ESPIPE;
+	}
+	zero_reset_config (dev);
+
+	switch (number) {
+	case CONFIG_SOURCE_SINK:
+		result = set_source_sink_config (dev, gfp_flags);
+		break;
+	case CONFIG_LOOPBACK:
+		result = set_loopback_config (dev, gfp_flags);
+		break;
+	default:
+		result = -EINVAL;
+		/* FALL THROUGH */
+	case 0:
+		return result;
+	}
+
+	if (!result && (!dev->in_ep || !dev->out_ep))
+		result = -ENODEV;
+	if (result)
+		zero_reset_config (dev);
+	else {
+		char *speed;
+
+		switch (gadget->speed) {
+		case USB_SPEED_LOW:	speed = "low"; break;
+		case USB_SPEED_FULL:	speed = "full"; break;
+		case USB_SPEED_HIGH:	speed = "high"; break;
+		default: 		speed = "?"; break;
+		}
+
+		dev->config = number;
+		INFO (dev, "%s speed config #%d: %s\n", speed, number,
+				(number == CONFIG_SOURCE_SINK)
+					? source_sink : loopback);
+	}
+	return result;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void zero_setup_complete (struct usb_ep *ep, struct usb_request *req)
+{
+	if (req->status || req->actual != req->length)
+		DBG ((struct zero_dev *) ep->driver_data,
+				"setup complete --> %d, %d/%d\n",
+				req->status, req->actual, req->length);
+}
+
+/*
+ * The setup() callback implements all the ep0 functionality that's
+ * not handled lower down, in hardware or the hardware driver (like
+ * device and endpoint feature flags, and their status).  It's all
+ * housekeeping for the gadget function we're implementing.  Most of
+ * the work is in config-specific setup.
+ */
+static int
+zero_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
+{
+	struct zero_dev		*dev = get_gadget_data (gadget);
+	struct usb_request	*req = dev->req;
+	int			value = -EOPNOTSUPP;
+	u16			w_index = ctrl->wIndex;
+	u16			w_value = ctrl->wValue;
+	u16			w_length = ctrl->wLength;
+
+	/* usually this stores reply data in the pre-allocated ep0 buffer,
+	 * but config change events will reconfigure hardware.
+	 */
+	req->zero = 0;
+	switch (ctrl->bRequest) {
+
+	case USB_REQ_GET_DESCRIPTOR:
+		if (ctrl->bRequestType != USB_DIR_IN)
+			goto unknown;
+		switch (w_value >> 8) {
+
+		case USB_DT_DEVICE:
+			value = min (w_length, (u16) sizeof device_desc);
+			memcpy (req->buf, &device_desc, value);
+			break;
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+		case USB_DT_DEVICE_QUALIFIER:
+			if (!gadget->is_dualspeed)
+				break;
+			value = min (w_length, (u16) sizeof dev_qualifier);
+			memcpy (req->buf, &dev_qualifier, value);
+			break;
+
+		case USB_DT_OTHER_SPEED_CONFIG:
+			if (!gadget->is_dualspeed)
+				break;
+			// FALLTHROUGH
+#endif /* CONFIG_USB_GADGET_DUALSPEED */
+		case USB_DT_CONFIG:
+			value = config_buf (gadget, req->buf,
+					w_value >> 8,
+					w_value & 0xff);
+			if (value >= 0)
+				value = min (w_length, (u16) value);
+			break;
+
+		case USB_DT_STRING:
+			/* wIndex == language code.
+			 * this driver only handles one language, you can
+			 * add string tables for other languages, using
+			 * any UTF-8 characters
+			 */
+			value = usb_gadget_get_string (&stringtab,
+					w_value & 0xff, req->buf);
+			if (value >= 0)
+				value = min (w_length, (u16) value);
+			break;
+		}
+		break;
+
+	/* currently two configs, two speeds */
+	case USB_REQ_SET_CONFIGURATION:
+		if (ctrl->bRequestType != 0)
+			goto unknown;
+		if (gadget->a_hnp_support)
+			DBG (dev, "HNP available\n");
+		else if (gadget->a_alt_hnp_support)
+			DBG (dev, "HNP needs a different root port\n");
+		else
+			VDBG (dev, "HNP inactive\n");
+		spin_lock (&dev->lock);
+		value = zero_set_config (dev, w_value, GFP_ATOMIC);
+		spin_unlock (&dev->lock);
+		break;
+	case USB_REQ_GET_CONFIGURATION:
+		if (ctrl->bRequestType != USB_DIR_IN)
+			goto unknown;
+		*(u8 *)req->buf = dev->config;
+		value = min (w_length, (u16) 1);
+		break;
+
+	/* until we add altsetting support, or other interfaces,
+	 * only 0/0 are possible.  pxa2xx only supports 0/0 (poorly)
+	 * and already killed pending endpoint I/O.
+	 */
+	case USB_REQ_SET_INTERFACE:
+		if (ctrl->bRequestType != USB_RECIP_INTERFACE)
+			goto unknown;
+		spin_lock (&dev->lock);
+		if (dev->config && w_index == 0 && w_value == 0) {
+			u8		config = dev->config;
+
+			/* resets interface configuration, forgets about
+			 * previous transaction state (queued bufs, etc)
+			 * and re-inits endpoint state (toggle etc)
+			 * no response queued, just zero status == success.
+			 * if we had more than one interface we couldn't
+			 * use this "reset the config" shortcut.
+			 */
+			zero_reset_config (dev);
+			zero_set_config (dev, config, GFP_ATOMIC);
+			value = 0;
+		}
+		spin_unlock (&dev->lock);
+		break;
+	case USB_REQ_GET_INTERFACE:
+		if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
+			goto unknown;
+		if (!dev->config)
+			break;
+		if (w_index != 0) {
+			value = -EDOM;
+			break;
+		}
+		*(u8 *)req->buf = 0;
+		value = min (w_length, (u16) 1);
+		break;
+
+	/*
+	 * These are the same vendor-specific requests supported by
+	 * Intel's USB 2.0 compliance test devices.  We exceed that
+	 * device spec by allowing multiple-packet requests.
+	 */
+	case 0x5b:	/* control WRITE test -- fill the buffer */
+		if (ctrl->bRequestType != (USB_DIR_OUT|USB_TYPE_VENDOR))
+			goto unknown;
+		if (w_value || w_index)
+			break;
+		/* just read that many bytes into the buffer */
+		if (w_length > USB_BUFSIZ)
+			break;
+		value = w_length;
+		break;
+	case 0x5c:	/* control READ test -- return the buffer */
+		if (ctrl->bRequestType != (USB_DIR_IN|USB_TYPE_VENDOR))
+			goto unknown;
+		if (w_value || w_index)
+			break;
+		/* expect those bytes are still in the buffer; send back */
+		if (w_length > USB_BUFSIZ
+				|| w_length != req->length)
+			break;
+		value = w_length;
+		break;
+
+	default:
+unknown:
+		VDBG (dev,
+			"unknown control req%02x.%02x v%04x i%04x l%d\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			w_value, w_index, w_length);
+	}
+
+	/* respond with data transfer before status phase? */
+	if (value >= 0) {
+		req->length = value;
+		req->zero = value < w_length;
+		value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0) {
+			DBG (dev, "ep_queue --> %d\n", value);
+			req->status = 0;
+			zero_setup_complete (gadget->ep0, req);
+		}
+	}
+
+	/* device either stalls (value < 0) or reports success */
+	return value;
+}
+
+static void
+zero_disconnect (struct usb_gadget *gadget)
+{
+	struct zero_dev		*dev = get_gadget_data (gadget);
+	unsigned long		flags;
+
+	spin_lock_irqsave (&dev->lock, flags);
+	zero_reset_config (dev);
+
+	/* a more significant application might have some non-usb
+	 * activities to quiesce here, saving resources like power
+	 * or pushing the notification up a network stack.
+	 */
+	spin_unlock_irqrestore (&dev->lock, flags);
+
+	/* next we may get setup() calls to enumerate new connections;
+	 * or an unbind() during shutdown (including removing module).
+	 */
+}
+
+static void
+zero_autoresume (unsigned long _dev)
+{
+	struct zero_dev	*dev = (struct zero_dev *) _dev;
+	int		status;
+
+	/* normally the host would be woken up for something
+	 * more significant than just a timer firing...
+	 */
+	if (dev->gadget->speed != USB_SPEED_UNKNOWN) {
+		status = usb_gadget_wakeup (dev->gadget);
+		DBG (dev, "wakeup --> %d\n", status);
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void
+zero_unbind (struct usb_gadget *gadget)
+{
+	struct zero_dev		*dev = get_gadget_data (gadget);
+
+	DBG (dev, "unbind\n");
+
+	/* we've already been disconnected ... no i/o is active */
+	if (dev->req)
+		free_ep_req (gadget->ep0, dev->req);
+	del_timer_sync (&dev->resume);
+	kfree (dev);
+	set_gadget_data (gadget, NULL);
+}
+
+static int
+zero_bind (struct usb_gadget *gadget)
+{
+	struct zero_dev		*dev;
+	struct usb_ep		*ep;
+
+	/* Bulk-only drivers like this one SHOULD be able to
+	 * autoconfigure on any sane usb controller driver,
+	 * but there may also be important quirks to address.
+	 */
+	usb_ep_autoconfig_reset (gadget);
+	ep = usb_ep_autoconfig (gadget, &fs_source_desc);
+	if (!ep) {
+autoconf_fail:
+		printk (KERN_ERR "%s: can't autoconfigure on %s\n",
+			shortname, gadget->name);
+		return -ENODEV;
+	}
+	EP_IN_NAME = ep->name;
+	ep->driver_data = ep;	/* claim */
+	
+	ep = usb_ep_autoconfig (gadget, &fs_sink_desc);
+	if (!ep)
+		goto autoconf_fail;
+	EP_OUT_NAME = ep->name;
+	ep->driver_data = ep;	/* claim */
+
+
+	/*
+	 * DRIVER POLICY CHOICE:  you may want to do this differently.
+	 * One thing to avoid is reusing a bcdDevice revision code
+	 * with different host-visible configurations or behavior
+	 * restrictions -- using ep1in/ep2out vs ep1out/ep3in, etc
+	 */
+	if (gadget_is_net2280 (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0201);
+	} else if (gadget_is_pxa (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0203);
+#if 0
+	} else if (gadget_is_sh(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0204);
+		/* SH has only one configuration; see "loopdefault" */
+		device_desc.bNumConfigurations = 1;
+		/* FIXME make 1 == default.bConfigurationValue */
+#endif
+	} else if (gadget_is_sa1100 (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0205);
+	} else if (gadget_is_goku (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0206);
+	} else if (gadget_is_mq11xx (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0207);
+	} else if (gadget_is_omap (gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0208);
+	} else if (gadget_is_lh7a40x(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0209);
+	} else if (gadget_is_n9604(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0210);
+	} else if (gadget_is_pxa27x(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0211);
+	} else if (gadget_is_s3c2410(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0212);
+	} else if (gadget_is_at91(gadget)) {
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x0213);
+	} else {
+		/* gadget zero is so simple (for now, no altsettings) that
+		 * it SHOULD NOT have problems with bulk-capable hardware.
+		 * so warn about unrcognized controllers, don't panic.
+		 *
+		 * things like configuration and altsetting numbering
+		 * can need hardware-specific attention though.
+		 */
+		printk (KERN_WARNING "%s: controller '%s' not recognized\n",
+			shortname, gadget->name);
+		device_desc.bcdDevice = __constant_cpu_to_le16 (0x9999);
+	}
+
+
+	/* ok, we made sense of the hardware ... */
+	dev = kmalloc (sizeof *dev, SLAB_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+	memset (dev, 0, sizeof *dev);
+	spin_lock_init (&dev->lock);
+	dev->gadget = gadget;
+	set_gadget_data (gadget, dev);
+
+	/* preallocate control response and buffer */
+	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
+	if (!dev->req)
+		goto enomem;
+	dev->req->buf = usb_ep_alloc_buffer (gadget->ep0, USB_BUFSIZ,
+				&dev->req->dma, GFP_KERNEL);
+	if (!dev->req->buf)
+		goto enomem;
+
+	dev->req->complete = zero_setup_complete;
+
+	device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
+
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+	/* assume ep0 uses the same value for both speeds ... */
+	dev_qualifier.bMaxPacketSize0 = device_desc.bMaxPacketSize0;
+
+	/* and that all endpoints are dual-speed */
+	hs_source_desc.bEndpointAddress = fs_source_desc.bEndpointAddress;
+	hs_sink_desc.bEndpointAddress = fs_sink_desc.bEndpointAddress;
+#endif
+
+	if (gadget->is_otg) {
+		otg_descriptor.bmAttributes |= USB_OTG_HNP,
+		source_sink_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		loopback_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
+	if (gadget->is_otg) {
+		otg_descriptor.bmAttributes |= USB_OTG_HNP,
+		source_sink_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		loopback_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
+	usb_gadget_set_selfpowered (gadget);
+
+	init_timer (&dev->resume);
+	dev->resume.function = zero_autoresume;
+	dev->resume.data = (unsigned long) dev;
+	if (autoresume) {
+		source_sink_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		loopback_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
+	gadget->ep0->driver_data = dev;
+
+	INFO (dev, "%s, version: " DRIVER_VERSION "\n", longname);
+	INFO (dev, "using %s, OUT %s IN %s\n", gadget->name,
+		EP_OUT_NAME, EP_IN_NAME);
+
+	snprintf (manufacturer, sizeof manufacturer, "%s %s with %s",
+		system_utsname.sysname, system_utsname.release,
+		gadget->name);
+
+	return 0;
+
+enomem:
+	zero_unbind (gadget);
+	return -ENOMEM;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void
+zero_suspend (struct usb_gadget *gadget)
+{
+	struct zero_dev		*dev = get_gadget_data (gadget);
+
+	if (gadget->speed == USB_SPEED_UNKNOWN)
+		return;
+
+	if (autoresume) {
+		mod_timer (&dev->resume, jiffies + (HZ * autoresume));
+		DBG (dev, "suspend, wakeup in %d seconds\n", autoresume);
+	} else
+		DBG (dev, "suspend\n");
+}
+
+static void
+zero_resume (struct usb_gadget *gadget)
+{
+	struct zero_dev		*dev = get_gadget_data (gadget);
+
+	DBG (dev, "resume\n");
+	del_timer (&dev->resume);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_gadget_driver zero_driver = {
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+	.speed		= USB_SPEED_HIGH,
+#else
+	.speed		= USB_SPEED_FULL,
+#endif
+	.function	= (char *) longname,
+	.bind		= zero_bind,
+	.unbind		= zero_unbind,
+
+	.setup		= zero_setup,
+	.disconnect	= zero_disconnect,
+
+	.suspend	= zero_suspend,
+	.resume		= zero_resume,
+
+	.driver 	= {
+		.name		= (char *) shortname,
+		// .shutdown = ...
+		// .suspend = ...
+		// .resume = ...
+	},
+};
+
+MODULE_AUTHOR ("David Brownell");
+MODULE_LICENSE ("Dual BSD/GPL");
+
+
+static int __init init (void)
+{
+	/* a real value would likely come through some id prom
+	 * or module option.  this one takes at least two packets.
+	 */
+	strlcpy (serial, "0123456789.0123456789.0123456789", sizeof serial);
+
+	return usb_gadget_register_driver (&zero_driver);
+}
+module_init (init);
+
+static void __exit cleanup (void)
+{
+	usb_gadget_unregister_driver (&zero_driver);
+}
+module_exit (cleanup);
+