[U-Boot] [PATCH v5 2/7] dfu:usb: DFU USB function (f_dfu) support for g_dnl composite gadget

[Lukasz Majewski <l.majewski@samsung.com>]

Support for f_dfu USB function.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Vasut <marex@denx.de>

---
Changes for v2:

- Replace kzalloc and kfree with free and calloc
- Reorganization of calloc calls
- Misspelling corrected
- Redesign of DFU state machine from "switch case" to function pointers
- Split the dfu_handle method to separate functions for each DFU state

Changes for v3:
- Missing parenthesis added to sizeof call

Changes for v4:
- Replace two puts with one
- Remove the 0xff at handle_getstate function
- Add const qualifier to struct definitions when possible

Changes for v5:
- None
---
 drivers/usb/gadget/Makefile |    1 +
 drivers/usb/gadget/f_dfu.c  |  749 +++++++++++++++++++++++++++++++++++++++++++
 drivers/usb/gadget/f_dfu.h  |  100 ++++++
 3 files changed, 850 insertions(+), 0 deletions(-)
 create mode 100644 drivers/usb/gadget/f_dfu.c
 create mode 100644 drivers/usb/gadget/f_dfu.h

diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 2c067c8..5bbdd36 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -30,6 +30,7 @@ ifdef CONFIG_USB_GADGET
 COBJS-y += epautoconf.o config.o usbstring.o
 COBJS-$(CONFIG_USB_GADGET_S3C_UDC_OTG) += s3c_udc_otg.o
 COBJS-$(CONFIG_USBDOWNLOAD_GADGET) += g_dnl.o
+COBJS-$(CONFIG_DFU_FUNCTION) += f_dfu.o
 endif
 ifdef CONFIG_USB_ETHER
 COBJS-y += ether.o epautoconf.o config.o usbstring.o
diff --git a/drivers/usb/gadget/f_dfu.c b/drivers/usb/gadget/f_dfu.c
new file mode 100644
index 0000000..3ec4c65
--- /dev/null
+++ b/drivers/usb/gadget/f_dfu.c
@@ -0,0 +1,749 @@
+/*
+ * f_dfu.c -- Device Firmware Update USB function
+ *
+ * Copyright (C) 2012 Samsung Electronics
+ * authors: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *          Lukasz Majewski <l.majewski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <errno.h>
+#include <common.h>
+#include <malloc.h>
+
+#include <linux/usb/ch9.h>
+#include <usbdescriptors.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
+
+#include <dfu.h>
+#include "f_dfu.h"
+
+struct f_dfu {
+	struct usb_function		usb_function;
+
+	struct usb_descriptor_header	**function;
+	struct usb_string		*strings;
+
+	/* when configured, we have one config */
+	u8				config;
+	u8				altsetting;
+	enum dfu_state			dfu_state;
+	unsigned int			dfu_status;
+
+	/* Send/received block number is handy for data integrity check */
+	int                             blk_seq_num;
+};
+
+typedef int (*dfu_state_fn) (struct f_dfu *,
+			     const struct usb_ctrlrequest *,
+			     struct usb_gadget *,
+			     struct usb_request *);
+
+static inline struct f_dfu *func_to_dfu(struct usb_function *f)
+{
+	return container_of(f, struct f_dfu, usb_function);
+}
+
+static const struct dfu_function_descriptor dfu_func = {
+	.bLength =		sizeof dfu_func,
+	.bDescriptorType =	DFU_DT_FUNC,
+	.bmAttributes =		DFU_BIT_WILL_DETACH |
+				DFU_BIT_MANIFESTATION_TOLERANT |
+				DFU_BIT_CAN_UPLOAD |
+				DFU_BIT_CAN_DNLOAD,
+	.wDetachTimeOut =	0,
+	.wTransferSize =	DFU_USB_BUFSIZ,
+	.bcdDFUVersion =	__constant_cpu_to_le16(0x0110),
+};
+
+static struct usb_interface_descriptor dfu_intf_runtime = {
+	.bLength =		sizeof dfu_intf_runtime,
+	.bDescriptorType =	USB_DT_INTERFACE,
+	.bNumEndpoints =	0,
+	.bInterfaceClass =	USB_CLASS_APP_SPEC,
+	.bInterfaceSubClass =	1,
+	.bInterfaceProtocol =	1,
+	/* .iInterface = DYNAMIC */
+};
+
+static struct usb_descriptor_header *dfu_runtime_descs[] = {
+	(struct usb_descriptor_header *) &dfu_intf_runtime,
+	NULL,
+};
+
+static const 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 =	1,
+};
+
+static const char dfu_name[] = "Device Firmware Upgrade";
+
+/*
+ * static strings, in UTF-8
+ *
+ * dfu_generic configuration
+ */
+static struct usb_string strings_dfu_generic[] = {
+	[0].s = dfu_name,
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings stringtab_dfu_generic = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_dfu_generic,
+};
+
+static struct usb_gadget_strings *dfu_generic_strings[] = {
+	&stringtab_dfu_generic,
+	NULL,
+};
+
+/*
+ * usb_function specific
+ */
+static struct usb_gadget_strings stringtab_dfu = {
+	.language	= 0x0409,	/* en-us */
+	/*
+	 * .strings
+	 *
+	 * assigned during initialization,
+	 * depends on number of flash entities
+	 *
+	 */
+};
+
+static struct usb_gadget_strings *dfu_strings[] = {
+	&stringtab_dfu,
+	NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static void dnload_request_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct f_dfu *f_dfu = req->context;
+
+	dfu_write(dfu_get_entity(f_dfu->altsetting), req->buf,
+		  req->length, f_dfu->blk_seq_num);
+
+	if (req->length == 0)
+		puts("DOWNLOAD ... OK\nCtrl+C to exit ...\n");
+}
+
+static void handle_getstatus(struct usb_request *req)
+{
+	struct dfu_status *dstat = (struct dfu_status *)req->buf;
+	struct f_dfu *f_dfu = req->context;
+
+	switch (f_dfu->dfu_state) {
+	case DFU_STATE_dfuDNLOAD_SYNC:
+	case DFU_STATE_dfuDNBUSY:
+		f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_IDLE;
+		break;
+	case DFU_STATE_dfuMANIFEST_SYNC:
+		break;
+	default:
+		break;
+	}
+
+	/* send status response */
+	dstat->bStatus = f_dfu->dfu_status;
+	dstat->bState = f_dfu->dfu_state;
+	dstat->iString = 0;
+}
+
+static void handle_getstate(struct usb_request *req)
+{
+	struct f_dfu *f_dfu = req->context;
+
+	((u8 *)req->buf)[0] = f_dfu->dfu_state;
+	req->actual = sizeof(u8);
+}
+
+static inline void to_dfu_mode(struct f_dfu *f_dfu)
+{
+	f_dfu->usb_function.strings = dfu_strings;
+	f_dfu->usb_function.hs_descriptors = f_dfu->function;
+}
+
+static inline void to_runtime_mode(struct f_dfu *f_dfu)
+{
+	f_dfu->usb_function.strings = NULL;
+	f_dfu->usb_function.hs_descriptors = dfu_runtime_descs;
+}
+
+static int handle_upload(struct usb_request *req, u16 len)
+{
+	struct f_dfu *f_dfu = req->context;
+
+	return dfu_read(dfu_get_entity(f_dfu->altsetting), req->buf,
+			req->length, f_dfu->blk_seq_num);
+}
+
+static int handle_dnload(struct usb_gadget *gadget, u16 len)
+{
+	struct usb_composite_dev *cdev = get_gadget_data(gadget);
+	struct usb_request *req = cdev->req;
+	struct f_dfu *f_dfu = req->context;
+
+	if (len == 0)
+		f_dfu->dfu_state = DFU_STATE_dfuMANIFEST_SYNC;
+
+	req->complete = dnload_request_complete;
+
+	return len;
+}
+
+/*-------------------------------------------------------------------------*/
+/* DFU state machine  */
+static int state_app_idle(struct f_dfu *f_dfu,
+			  const struct usb_ctrlrequest *ctrl,
+			  struct usb_gadget *gadget,
+			  struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	case USB_REQ_DFU_DETACH:
+		f_dfu->dfu_state = DFU_STATE_appDETACH;
+		to_dfu_mode(f_dfu);
+		f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		value = RET_ZLP;
+		break;
+	default:
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_app_detach(struct f_dfu *f_dfu,
+			    const struct usb_ctrlrequest *ctrl,
+			    struct usb_gadget *gadget,
+			    struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_appIDLE;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_idle(struct f_dfu *f_dfu,
+			  const struct usb_ctrlrequest *ctrl,
+			  struct usb_gadget *gadget,
+			  struct usb_request *req)
+{
+	u16 w_value = le16_to_cpu(ctrl->wValue);
+	u16 len = le16_to_cpu(ctrl->wLength);
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_DNLOAD:
+		if (len == 0) {
+			f_dfu->dfu_state = DFU_STATE_dfuERROR;
+			value = RET_STALL;
+			break;
+		}
+		f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
+		f_dfu->blk_seq_num = w_value;
+		value = handle_dnload(gadget, len);
+		break;
+	case USB_REQ_DFU_UPLOAD:
+		f_dfu->dfu_state = DFU_STATE_dfuUPLOAD_IDLE;
+		f_dfu->blk_seq_num = 0;
+		value = handle_upload(req, len);
+		break;
+	case USB_REQ_DFU_ABORT:
+		/* no zlp? */
+		value = RET_ZLP;
+		break;
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	case USB_REQ_DFU_DETACH:
+		/*
+		 * Proprietary extension: 'detach' from idle mode and
+		 * get back to runtime mode in case of USB Reset.  As
+		 * much as I dislike this, we just can't use every USB
+		 * bus reset to switch back to runtime mode, since at
+		 * least the Linux USB stack likes to send a number of
+		 * resets in a row :(
+		 */
+		f_dfu->dfu_state =
+			DFU_STATE_dfuMANIFEST_WAIT_RST;
+		to_runtime_mode(f_dfu);
+		f_dfu->dfu_state = DFU_STATE_appIDLE;
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_dnload_sync(struct f_dfu *f_dfu,
+				 const struct usb_ctrlrequest *ctrl,
+				 struct usb_gadget *gadget,
+				 struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_dnbusy(struct f_dfu *f_dfu,
+			    const struct usb_ctrlrequest *ctrl,
+			    struct usb_gadget *gadget,
+			    struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_dnload_idle(struct f_dfu *f_dfu,
+				 const struct usb_ctrlrequest *ctrl,
+				 struct usb_gadget *gadget,
+				 struct usb_request *req)
+{
+	u16 w_value = le16_to_cpu(ctrl->wValue);
+	u16 len = le16_to_cpu(ctrl->wLength);
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_DNLOAD:
+		f_dfu->dfu_state = DFU_STATE_dfuDNLOAD_SYNC;
+		f_dfu->blk_seq_num = w_value;
+		value = handle_dnload(gadget, len);
+		break;
+	case USB_REQ_DFU_ABORT:
+		f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		value = RET_ZLP;
+		break;
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_manifest_sync(struct f_dfu *f_dfu,
+				   const struct usb_ctrlrequest *ctrl,
+				   struct usb_gadget *gadget,
+				   struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		/* We're MainfestationTolerant */
+		f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		handle_getstatus(req);
+		f_dfu->blk_seq_num = 0;
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_upload_idle(struct f_dfu *f_dfu,
+				 const struct usb_ctrlrequest *ctrl,
+				 struct usb_gadget *gadget,
+				 struct usb_request *req)
+{
+	u16 w_value = le16_to_cpu(ctrl->wValue);
+	u16 len = le16_to_cpu(ctrl->wLength);
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_UPLOAD:
+		/* state transition if less data then requested */
+		f_dfu->blk_seq_num = w_value;
+		value = handle_upload(req, len);
+		if (value >= 0 && value < len)
+			f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		break;
+	case USB_REQ_DFU_ABORT:
+		f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		/* no zlp? */
+		value = RET_ZLP;
+		break;
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static int state_dfu_error(struct f_dfu *f_dfu,
+				 const struct usb_ctrlrequest *ctrl,
+				 struct usb_gadget *gadget,
+				 struct usb_request *req)
+{
+	int value = 0;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_DFU_GETSTATUS:
+		handle_getstatus(req);
+		value = RET_STAT_LEN;
+		break;
+	case USB_REQ_DFU_GETSTATE:
+		handle_getstate(req);
+		break;
+	case USB_REQ_DFU_CLRSTATUS:
+		f_dfu->dfu_state = DFU_STATE_dfuIDLE;
+		f_dfu->dfu_status = DFU_STATUS_OK;
+		/* no zlp? */
+		value = RET_ZLP;
+		break;
+	default:
+		f_dfu->dfu_state = DFU_STATE_dfuERROR;
+		value = RET_STALL;
+		break;
+	}
+
+	return value;
+}
+
+static dfu_state_fn dfu_state[] = {
+	state_app_idle,          /* DFU_STATE_appIDLE */
+	state_app_detach,        /* DFU_STATE_appDETACH */
+	state_dfu_idle,          /* DFU_STATE_dfuIDLE */
+	state_dfu_dnload_sync,   /* DFU_STATE_dfuDNLOAD_SYNC */
+	state_dfu_dnbusy,        /* DFU_STATE_dfuDNBUSY */
+	state_dfu_dnload_idle,   /* DFU_STATE_dfuDNLOAD_IDLE */
+	state_dfu_manifest_sync, /* DFU_STATE_dfuMANIFEST_SYNC */
+	NULL,                    /* DFU_STATE_dfuMANIFEST */
+	NULL,                    /* DFU_STATE_dfuMANIFEST_WAIT_RST */
+	state_dfu_upload_idle,   /* DFU_STATE_dfuUPLOAD_IDLE */
+	state_dfu_error          /* DFU_STATE_dfuERROR */
+};
+
+static int
+dfu_handle(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+	struct usb_gadget *gadget = f->config->cdev->gadget;
+	struct usb_request *req = f->config->cdev->req;
+	struct f_dfu *f_dfu = f->config->cdev->req->context;
+	u16 len = le16_to_cpu(ctrl->wLength);
+	u16 w_value = le16_to_cpu(ctrl->wValue);
+	int value = 0;
+	u8 req_type = ctrl->bRequestType & USB_TYPE_MASK;
+
+	debug("w_value: 0x%x len: 0x%x\n", w_value, len);
+	debug("req_type: 0x%x ctrl->bRequest: 0x%x f_dfu->dfu_state: 0x%x\n",
+	       req_type, ctrl->bRequest, f_dfu->dfu_state);
+
+	if (req_type == USB_TYPE_STANDARD) {
+		if (ctrl->bRequest == USB_REQ_GET_DESCRIPTOR &&
+		    (w_value >> 8) == DFU_DT_FUNC) {
+			value = min(len, (u16) sizeof(dfu_func));
+			memcpy(req->buf, &dfu_func, value);
+		}
+	} else /* DFU specific request */
+		value = dfu_state[f_dfu->dfu_state] (f_dfu, ctrl, gadget, req);
+
+	if (value >= 0) {
+		req->length = value;
+		req->zero = value < len;
+		value = usb_ep_queue(gadget->ep0, req, 0);
+		if (value < 0) {
+			debug("ep_queue --> %d\n", value);
+			req->status = 0;
+		}
+	}
+
+	return value;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int
+dfu_prepare_strings(struct f_dfu *f_dfu, int n)
+{
+	struct dfu_entity *de = NULL;
+	int i = 0;
+
+	f_dfu->strings = calloc(sizeof(struct usb_string), n + 1);
+	if (!f_dfu->strings)
+		goto enomem;
+
+	for (i = 0; i < n; ++i) {
+		de = dfu_get_entity(i);
+		f_dfu->strings[i].s = de->name;
+	}
+
+	f_dfu->strings[i].id = 0;
+	f_dfu->strings[i].s = NULL;
+
+	return 0;
+
+enomem:
+	while (i)
+		f_dfu->strings[--i].s = NULL;
+
+	free(f_dfu->strings);
+
+	return -ENOMEM;
+}
+
+static int dfu_prepare_function(struct f_dfu *f_dfu, int n)
+{
+	struct usb_interface_descriptor *d;
+	int i = 0;
+
+	f_dfu->function = calloc(sizeof(struct usb_descriptor_header *), n);
+	if (!f_dfu->function)
+		goto enomem;
+
+	for (i = 0; i < n; ++i) {
+		d = calloc(sizeof(*d), 1);
+		if (!d)
+			goto enomem;
+
+		d->bLength =		sizeof(*d);
+		d->bDescriptorType =	USB_DT_INTERFACE;
+		d->bAlternateSetting =	i;
+		d->bNumEndpoints =	0;
+		d->bInterfaceClass =	USB_CLASS_APP_SPEC;
+		d->bInterfaceSubClass =	1;
+		d->bInterfaceProtocol =	2;
+
+		f_dfu->function[i] = (struct usb_descriptor_header *)d;
+	}
+	f_dfu->function[i] = NULL;
+
+	return 0;
+
+enomem:
+	while (i) {
+		free(f_dfu->function[--i]);
+		f_dfu->function[i] = NULL;
+	}
+	free(f_dfu->function);
+
+	return -ENOMEM;
+}
+
+static int dfu_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct f_dfu *f_dfu = func_to_dfu(f);
+	int alt_num = dfu_get_alt_number();
+	int rv, id, i;
+
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	dfu_intf_runtime.bInterfaceNumber = id;
+
+	f_dfu->dfu_state = DFU_STATE_appIDLE;
+	f_dfu->dfu_status = DFU_STATUS_OK;
+
+	rv = dfu_prepare_function(f_dfu, alt_num);
+	if (rv)
+		goto error;
+
+	rv = dfu_prepare_strings(f_dfu, alt_num);
+	if (rv)
+		goto error;
+	for (i = 0; i < alt_num; i++) {
+		id = usb_string_id(cdev);
+		if (id < 0)
+			return id;
+		f_dfu->strings[i].id = id;
+		((struct usb_interface_descriptor *)f_dfu->function[i])
+			->iInterface = id;
+	}
+
+	stringtab_dfu.strings = f_dfu->strings;
+
+	cdev->req->context = f_dfu;
+
+error:
+	return rv;
+}
+
+static void dfu_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_dfu *f_dfu = func_to_dfu(f);
+	int alt_num = dfu_get_alt_number();
+	int i;
+
+	if (f_dfu->strings) {
+		i = alt_num;
+		while (i)
+			f_dfu->strings[--i].s = NULL;
+
+		free(f_dfu->strings);
+	}
+
+	if (f_dfu->function) {
+		i = alt_num;
+		while (i) {
+			free(f_dfu->function[--i]);
+			f_dfu->function[i] = NULL;
+		}
+		free(f_dfu->function);
+	}
+
+	free(f_dfu);
+}
+
+static int dfu_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct f_dfu *f_dfu = func_to_dfu(f);
+
+	debug("%s: intf:%d alt:%d\n", __func__, intf, alt);
+
+	f_dfu->altsetting = alt;
+
+	return 0;
+}
+
+/* TODO: is this really what we need here? */
+static void dfu_disable(struct usb_function *f)
+{
+	struct f_dfu *f_dfu = func_to_dfu(f);
+	if (f_dfu->config == 0)
+		return;
+
+	debug("%s: reset config\n", __func__);
+
+	f_dfu->config = 0;
+}
+
+static int dfu_bind_config(struct usb_configuration *c)
+{
+	struct f_dfu *f_dfu;
+	int status;
+
+	f_dfu = calloc(sizeof(*f_dfu), 1);
+	if (!f_dfu)
+		return -ENOMEM;
+	f_dfu->usb_function.name = "dfu";
+	f_dfu->usb_function.hs_descriptors = dfu_runtime_descs;
+	f_dfu->usb_function.bind = dfu_bind;
+	f_dfu->usb_function.unbind = dfu_unbind;
+	f_dfu->usb_function.set_alt = dfu_set_alt;
+	f_dfu->usb_function.disable = dfu_disable;
+	f_dfu->usb_function.strings = dfu_generic_strings,
+	f_dfu->usb_function.setup = dfu_handle,
+
+	status = usb_add_function(c, &f_dfu->usb_function);
+	if (status)
+		free(f_dfu);
+
+	return status;
+}
+
+int dfu_add(struct usb_configuration *c)
+{
+	int id;
+
+	id = usb_string_id(c->cdev);
+	if (id < 0)
+		return id;
+	strings_dfu_generic[0].id = id;
+	dfu_intf_runtime.iInterface = id;
+
+	debug("%s: cdev: 0x%p gadget:0x%p gadget->ep0: 0x%p\n", __func__,
+	       c->cdev, c->cdev->gadget, c->cdev->gadget->ep0);
+
+	return dfu_bind_config(c);
+}
diff --git a/drivers/usb/gadget/f_dfu.h b/drivers/usb/gadget/f_dfu.h
new file mode 100644
index 0000000..023e1ad
--- /dev/null
+++ b/drivers/usb/gadget/f_dfu.h
@@ -0,0 +1,100 @@
+/*
+ * f_dfu.h -- Device Firmware Update gadget
+ *
+ * Copyright (C) 2011-2012 Samsung Electronics
+ * author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __F_DFU_H_
+#define __F_DFU_H_
+
+#include <linux/compiler.h>
+#include <linux/usb/composite.h>
+
+#define DFU_CONFIG_VAL			1
+#define DFU_DT_FUNC			0x21
+
+#define DFU_BIT_WILL_DETACH		(0x1 << 3)
+#define DFU_BIT_MANIFESTATION_TOLERANT	(0x1 << 2)
+#define DFU_BIT_CAN_UPLOAD		(0x1 << 1)
+#define DFU_BIT_CAN_DNLOAD		0x1
+
+/* big enough to hold our biggest descriptor */
+#define DFU_USB_BUFSIZ			4096
+
+#define USB_REQ_DFU_DETACH		0x00
+#define USB_REQ_DFU_DNLOAD		0x01
+#define USB_REQ_DFU_UPLOAD		0x02
+#define USB_REQ_DFU_GETSTATUS		0x03
+#define USB_REQ_DFU_CLRSTATUS		0x04
+#define USB_REQ_DFU_GETSTATE		0x05
+#define USB_REQ_DFU_ABORT		0x06
+
+#define DFU_STATUS_OK			0x00
+#define DFU_STATUS_errTARGET		0x01
+#define DFU_STATUS_errFILE		0x02
+#define DFU_STATUS_errWRITE		0x03
+#define DFU_STATUS_errERASE		0x04
+#define DFU_STATUS_errCHECK_ERASED	0x05
+#define DFU_STATUS_errPROG		0x06
+#define DFU_STATUS_errVERIFY		0x07
+#define DFU_STATUS_errADDRESS		0x08
+#define DFU_STATUS_errNOTDONE		0x09
+#define DFU_STATUS_errFIRMWARE		0x0a
+#define DFU_STATUS_errVENDOR		0x0b
+#define DFU_STATUS_errUSBR		0x0c
+#define DFU_STATUS_errPOR		0x0d
+#define DFU_STATUS_errUNKNOWN		0x0e
+#define DFU_STATUS_errSTALLEDPKT	0x0f
+
+#define RET_STALL			-1
+#define RET_ZLP				0
+#define RET_STAT_LEN			6
+
+enum dfu_state {
+	DFU_STATE_appIDLE		= 0,
+	DFU_STATE_appDETACH		= 1,
+	DFU_STATE_dfuIDLE		= 2,
+	DFU_STATE_dfuDNLOAD_SYNC	= 3,
+	DFU_STATE_dfuDNBUSY		= 4,
+	DFU_STATE_dfuDNLOAD_IDLE	= 5,
+	DFU_STATE_dfuMANIFEST_SYNC	= 6,
+	DFU_STATE_dfuMANIFEST		= 7,
+	DFU_STATE_dfuMANIFEST_WAIT_RST	= 8,
+	DFU_STATE_dfuUPLOAD_IDLE	= 9,
+	DFU_STATE_dfuERROR		= 10,
+};
+
+struct dfu_status {
+	__u8				bStatus;
+	__u8				bwPollTimeout[3];
+	__u8				bState;
+	__u8				iString;
+} __packed;
+
+struct dfu_function_descriptor {
+	__u8				bLength;
+	__u8				bDescriptorType;
+	__u8				bmAttributes;
+	__le16				wDetachTimeOut;
+	__le16				wTransferSize;
+	__le16				bcdDFUVersion;
+} __packed;
+
+/* configuration-specific linkup */
+int dfu_add(struct usb_configuration *c);
+#endif /* __F_DFU_H_ */
-- 
1.7.2.3