usb: gadget: RNDIS function driver for QCOM chipsets

New function driver to support RNDIS with adaptions to
QCOM chipsets (Data path is over SPS BAM-to-BAM).

CRs-Fixed: 361085
Change-Id: I90dcb52e4a4fe939e2150e89d794aaddac4392f5
Signed-off-by: Ofir Cohen <ofirc@codeaurora.org>
diff --git a/drivers/usb/gadget/android.c b/drivers/usb/gadget/android.c
index 54c486e..ac88636 100644
--- a/drivers/usb/gadget/android.c
+++ b/drivers/usb/gadget/android.c
@@ -72,6 +72,7 @@
 #include "u_bam_data.c"
 #include "f_mbim.c"
 #include "f_qc_ecm.c"
+#include "f_qc_rndis.c"
 #include "u_qc_ether.c"
 #ifdef CONFIG_TARGET_CORE
 #include "f_tcm.c"
@@ -965,6 +966,7 @@
 struct rndis_function_config {
 	u8      ethaddr[ETH_ALEN];
 	u32     vendorID;
+	u8      max_pkt_per_xfer;
 	char	manufacturer[256];
 	/* "Wireless" RNDIS; auto-detected by Windows */
 	bool	wceis;
@@ -986,6 +988,22 @@
 	f->config = NULL;
 }
 
+static int rndis_qc_function_init(struct android_usb_function *f,
+					struct usb_composite_dev *cdev)
+{
+	f->config = kzalloc(sizeof(struct rndis_function_config), GFP_KERNEL);
+	if (!f->config)
+		return -ENOMEM;
+
+	return rndis_qc_init();
+}
+
+static void rndis_qc_function_cleanup(struct android_usb_function *f)
+{
+	rndis_qc_cleanup();
+	kfree(f->config);
+}
+
 static int
 rndis_function_bind_config(struct android_usb_function *f,
 		struct usb_configuration *c)
@@ -1024,12 +1042,56 @@
 					   rndis->manufacturer);
 }
 
+static int rndis_qc_function_bind_config(struct android_usb_function *f,
+					struct usb_configuration *c)
+{
+	int ret;
+	struct rndis_function_config *rndis = f->config;
+
+	if (!rndis) {
+		pr_err("%s: rndis_pdata\n", __func__);
+		return -EINVAL;
+	}
+
+	pr_info("%s MAC: %02X:%02X:%02X:%02X:%02X:%02X\n", __func__,
+		rndis->ethaddr[0], rndis->ethaddr[1], rndis->ethaddr[2],
+		rndis->ethaddr[3], rndis->ethaddr[4], rndis->ethaddr[5]);
+
+	ret = gether_qc_setup_name(c->cdev->gadget, rndis->ethaddr, "rndis");
+	if (ret) {
+		pr_err("%s: gether_setup failed\n", __func__);
+		return ret;
+	}
+
+	if (rndis->wceis) {
+		/* "Wireless" RNDIS; auto-detected by Windows */
+		rndis_qc_iad_descriptor.bFunctionClass =
+						USB_CLASS_WIRELESS_CONTROLLER;
+		rndis_qc_iad_descriptor.bFunctionSubClass = 0x01;
+		rndis_qc_iad_descriptor.bFunctionProtocol = 0x03;
+		rndis_qc_control_intf.bInterfaceClass =
+						USB_CLASS_WIRELESS_CONTROLLER;
+		rndis_qc_control_intf.bInterfaceSubClass =	 0x01;
+		rndis_qc_control_intf.bInterfaceProtocol =	 0x03;
+	}
+
+	return rndis_qc_bind_config_vendor(c, rndis->ethaddr, rndis->vendorID,
+				    rndis->manufacturer,
+					rndis->max_pkt_per_xfer);
+}
+
 static void rndis_function_unbind_config(struct android_usb_function *f,
 						struct usb_configuration *c)
 {
 	gether_cleanup();
 }
 
+static void rndis_qc_function_unbind_config(struct android_usb_function *f,
+						struct usb_configuration *c)
+{
+	gether_qc_cleanup();
+}
+
 static ssize_t rndis_manufacturer_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -1136,11 +1198,38 @@
 static DEVICE_ATTR(vendorID, S_IRUGO | S_IWUSR, rndis_vendorID_show,
 						rndis_vendorID_store);
 
+static ssize_t rndis_max_pkt_per_xfer_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct android_usb_function *f = dev_get_drvdata(dev);
+	struct rndis_function_config *config = f->config;
+	return snprintf(buf, PAGE_SIZE, "%d\n", config->max_pkt_per_xfer);
+}
+
+static ssize_t rndis_max_pkt_per_xfer_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct android_usb_function *f = dev_get_drvdata(dev);
+	struct rndis_function_config *config = f->config;
+	int value;
+
+	if (sscanf(buf, "%d", &value) == 1) {
+		config->max_pkt_per_xfer = value;
+		return size;
+	}
+	return -EINVAL;
+}
+
+static DEVICE_ATTR(max_pkt_per_xfer, S_IRUGO | S_IWUSR,
+				   rndis_max_pkt_per_xfer_show,
+				   rndis_max_pkt_per_xfer_store);
+
 static struct device_attribute *rndis_function_attributes[] = {
 	&dev_attr_manufacturer,
 	&dev_attr_wceis,
 	&dev_attr_ethaddr,
 	&dev_attr_vendorID,
+	&dev_attr_max_pkt_per_xfer,
 	NULL
 };
 
@@ -1153,6 +1242,14 @@
 	.attributes	= rndis_function_attributes,
 };
 
+static struct android_usb_function rndis_qc_function = {
+	.name		= "rndis_qc",
+	.init		= rndis_qc_function_init,
+	.cleanup	= rndis_qc_function_cleanup,
+	.bind_config	= rndis_qc_function_bind_config,
+	.unbind_config	= rndis_qc_function_unbind_config,
+	.attributes	= rndis_function_attributes,
+};
 
 struct mass_storage_function_config {
 	struct fsg_config fsg;
@@ -1356,6 +1453,7 @@
 	&mtp_function,
 	&ptp_function,
 	&rndis_function,
+	&rndis_qc_function,
 	&mass_storage_function,
 	&accessory_function,
 	&uasp_function,
diff --git a/drivers/usb/gadget/f_qc_rndis.c b/drivers/usb/gadget/f_qc_rndis.c
new file mode 100644
index 0000000..dcf307d
--- /dev/null
+++ b/drivers/usb/gadget/f_qc_rndis.c
@@ -0,0 +1,1151 @@
+/*
+ * f_qc_rndis.c -- RNDIS link function driver
+ *
+ * Copyright (C) 2003-2005,2008 David Brownell
+ * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
+ * Copyright (C) 2008 Nokia Corporation
+ * Copyright (C) 2009 Samsung Electronics
+ *			Author: Michal Nazarewicz (mina86@mina86.com)
+ * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ *
+ * 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
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/etherdevice.h>
+
+#include <linux/atomic.h>
+
+#include "u_ether.h"
+#include "u_qc_ether.h"
+#include "rndis.h"
+
+
+/*
+ * This function is an RNDIS Ethernet port -- a Microsoft protocol that's
+ * been promoted instead of the standard CDC Ethernet.  The published RNDIS
+ * spec is ambiguous, incomplete, and needlessly complex.  Variants such as
+ * ActiveSync have even worse status in terms of specification.
+ *
+ * In short:  it's a protocol controlled by (and for) Microsoft, not for an
+ * Open ecosystem or markets.  Linux supports it *only* because Microsoft
+ * doesn't support the CDC Ethernet standard.
+ *
+ * The RNDIS data transfer model is complex, with multiple Ethernet packets
+ * per USB message, and out of band data.  The control model is built around
+ * what's essentially an "RNDIS RPC" protocol.  It's all wrapped in a CDC ACM
+ * (modem, not Ethernet) veneer, with those ACM descriptors being entirely
+ * useless (they're ignored).  RNDIS expects to be the only function in its
+ * configuration, so it's no real help if you need composite devices; and
+ * it expects to be the first configuration too.
+ *
+ * There is a single technical advantage of RNDIS over CDC Ethernet, if you
+ * discount the fluff that its RPC can be made to deliver: it doesn't need
+ * a NOP altsetting for the data interface.  That lets it work on some of the
+ * "so smart it's stupid" hardware which takes over configuration changes
+ * from the software, and adds restrictions like "no altsettings".
+ *
+ * Unfortunately MSFT's RNDIS drivers are buggy.  They hang or oops, and
+ * have all sorts of contrary-to-specification oddities that can prevent
+ * them from working sanely.  Since bugfixes (or accurate specs, letting
+ * Linux work around those bugs) are unlikely to ever come from MSFT, you
+ * may want to avoid using RNDIS on purely operational grounds.
+ *
+ * Omissions from the RNDIS 1.0 specification include:
+ *
+ *   - Power management ... references data that's scattered around lots
+ *     of other documentation, which is incorrect/incomplete there too.
+ *
+ *   - There are various undocumented protocol requirements, like the need
+ *     to send garbage in some control-OUT messages.
+ *
+ *   - MS-Windows drivers sometimes emit undocumented requests.
+ *
+ * This function is based on RNDIS link function driver and
+ * contains MSM specific implementation.
+ */
+
+struct f_rndis_qc {
+	struct qc_gether			port;
+	u8				ctrl_id, data_id;
+	u8				ethaddr[ETH_ALEN];
+	u32				vendorID;
+	u8				max_pkt_per_xfer;
+	const char			*manufacturer;
+	int				config;
+	atomic_t		ioctl_excl;
+	atomic_t		open_excl;
+
+	struct usb_ep			*notify;
+	struct usb_request		*notify_req;
+	atomic_t			notify_count;
+};
+
+static inline struct f_rndis_qc *func_to_rndis_qc(struct usb_function *f)
+{
+	return container_of(f, struct f_rndis_qc, port.func);
+}
+
+/* peak (theoretical) bulk transfer rate in bits-per-second */
+static unsigned int rndis_qc_bitrate(struct usb_gadget *g)
+{
+	if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
+		return 13 * 1024 * 8 * 1000 * 8;
+	else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
+		return 13 * 512 * 8 * 1000 * 8;
+	else
+		return 19 * 64 * 1 * 1000 * 8;
+}
+
+/*-------------------------------------------------------------------------*/
+
+#define RNDIS_QC_LOG2_STATUS_INTERVAL_MSEC	5	/* 1 << 5 == 32 msec */
+#define RNDIS_QC_STATUS_BYTECOUNT		8	/* 8 bytes data */
+
+/* currently only one rndis instance is supported */
+#define RNDIS_QC_NO_PORTS					1
+
+/* default max packets per tarnsfer value */
+#define DEFAULT_MAX_PKT_PER_XFER			15
+
+
+#define RNDIS_QC_IOCTL_MAGIC		'i'
+#define RNDIS_QC_GET_MAX_PKT_PER_XFER   _IOR(RNDIS_QC_IOCTL_MAGIC, 1, u8)
+
+
+/* interface descriptor: */
+
+static struct usb_interface_descriptor rndis_qc_control_intf = {
+	.bLength =		sizeof rndis_qc_control_intf,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	/* .bInterfaceNumber = DYNAMIC */
+	/* status endpoint is optional; this could be patched later */
+	.bNumEndpoints =	1,
+	.bInterfaceClass =	USB_CLASS_COMM,
+	.bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
+	.bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
+	/* .iInterface = DYNAMIC */
+};
+
+static struct usb_cdc_header_desc rndis_qc_header_desc = {
+	.bLength =		sizeof rndis_qc_header_desc,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
+
+	.bcdCDC =		cpu_to_le16(0x0110),
+};
+
+static struct usb_cdc_call_mgmt_descriptor rndis_qc_call_mgmt_descriptor = {
+	.bLength =		sizeof rndis_qc_call_mgmt_descriptor,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubType =	USB_CDC_CALL_MANAGEMENT_TYPE,
+
+	.bmCapabilities =	0x00,
+	.bDataInterface =	0x01,
+};
+
+static struct usb_cdc_acm_descriptor rndis_qc_acm_descriptor = {
+	.bLength =		sizeof rndis_qc_acm_descriptor,
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubType =	USB_CDC_ACM_TYPE,
+
+	.bmCapabilities =	0x00,
+};
+
+static struct usb_cdc_union_desc rndis_qc_union_desc = {
+	.bLength =		sizeof(rndis_qc_union_desc),
+	.bDescriptorType =	USB_DT_CS_INTERFACE,
+	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
+	/* .bMasterInterface0 =	DYNAMIC */
+	/* .bSlaveInterface0 =	DYNAMIC */
+};
+
+/* the data interface has two bulk endpoints */
+
+static struct usb_interface_descriptor rndis_qc_data_intf = {
+	.bLength =		sizeof rndis_qc_data_intf,
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	/* .bInterfaceNumber = DYNAMIC */
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_CDC_DATA,
+	.bInterfaceSubClass =	0,
+	.bInterfaceProtocol =	0,
+	/* .iInterface = DYNAMIC */
+};
+
+
+static struct usb_interface_assoc_descriptor
+rndis_qc_iad_descriptor = {
+	.bLength =		sizeof rndis_qc_iad_descriptor,
+	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,
+	.bFirstInterface =	0, /* XXX, hardcoded */
+	.bInterfaceCount =	2, /* control + data */
+	.bFunctionClass =	USB_CLASS_COMM,
+	.bFunctionSubClass =	USB_CDC_SUBCLASS_ETHERNET,
+	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
+	/* .iFunction = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor rndis_qc_fs_notify_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(RNDIS_QC_STATUS_BYTECOUNT),
+	.bInterval =		1 << RNDIS_QC_LOG2_STATUS_INTERVAL_MSEC,
+};
+
+static struct usb_endpoint_descriptor rndis_qc_fs_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor rndis_qc_fs_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *eth_qc_fs_function[] = {
+	(struct usb_descriptor_header *) &rndis_qc_iad_descriptor,
+	/* control interface matches ACM, not Ethernet */
+	(struct usb_descriptor_header *) &rndis_qc_control_intf,
+	(struct usb_descriptor_header *) &rndis_qc_header_desc,
+	(struct usb_descriptor_header *) &rndis_qc_call_mgmt_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_acm_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_union_desc,
+	(struct usb_descriptor_header *) &rndis_qc_fs_notify_desc,
+	/* data interface has no altsetting */
+	(struct usb_descriptor_header *) &rndis_qc_data_intf,
+	(struct usb_descriptor_header *) &rndis_qc_fs_in_desc,
+	(struct usb_descriptor_header *) &rndis_qc_fs_out_desc,
+	NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor rndis_qc_hs_notify_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(RNDIS_QC_STATUS_BYTECOUNT),
+	.bInterval =		RNDIS_QC_LOG2_STATUS_INTERVAL_MSEC + 4,
+};
+static struct usb_endpoint_descriptor rndis_qc_hs_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor rndis_qc_hs_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *eth_qc_hs_function[] = {
+	(struct usb_descriptor_header *) &rndis_qc_iad_descriptor,
+	/* control interface matches ACM, not Ethernet */
+	(struct usb_descriptor_header *) &rndis_qc_control_intf,
+	(struct usb_descriptor_header *) &rndis_qc_header_desc,
+	(struct usb_descriptor_header *) &rndis_qc_call_mgmt_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_acm_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_union_desc,
+	(struct usb_descriptor_header *) &rndis_qc_hs_notify_desc,
+	/* data interface has no altsetting */
+	(struct usb_descriptor_header *) &rndis_qc_data_intf,
+	(struct usb_descriptor_header *) &rndis_qc_hs_in_desc,
+	(struct usb_descriptor_header *) &rndis_qc_hs_out_desc,
+	NULL,
+};
+
+/* super speed support: */
+
+static struct usb_endpoint_descriptor rndis_qc_ss_notify_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_INT,
+	.wMaxPacketSize =	cpu_to_le16(STATUS_BYTECOUNT),
+	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
+};
+
+static struct usb_ss_ep_comp_descriptor rndis_qc_ss_intr_comp_desc = {
+	.bLength =		sizeof ss_intr_comp_desc,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+
+	/* the following 3 values can be tweaked if necessary */
+	/* .bMaxBurst =		0, */
+	/* .bmAttributes =	0, */
+	.wBytesPerInterval =	cpu_to_le16(STATUS_BYTECOUNT),
+};
+
+static struct usb_endpoint_descriptor rndis_qc_ss_in_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_endpoint_descriptor rndis_qc_ss_out_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor rndis_qc_ss_bulk_comp_desc = {
+	.bLength =		sizeof ss_bulk_comp_desc,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+
+	/* the following 2 values can be tweaked if necessary */
+	/* .bMaxBurst =		0, */
+	/* .bmAttributes =	0, */
+};
+
+static struct usb_descriptor_header *eth_qc_ss_function[] = {
+	(struct usb_descriptor_header *) &rndis_iad_descriptor,
+
+	/* control interface matches ACM, not Ethernet */
+	(struct usb_descriptor_header *) &rndis_qc_control_intf,
+	(struct usb_descriptor_header *) &rndis_qc_header_desc,
+	(struct usb_descriptor_header *) &rndis_qc_call_mgmt_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_acm_descriptor,
+	(struct usb_descriptor_header *) &rndis_qc_union_desc,
+	(struct usb_descriptor_header *) &rndis_qc_ss_notify_desc,
+	(struct usb_descriptor_header *) &rndis_qc_ss_intr_comp_desc,
+
+	/* data interface has no altsetting */
+	(struct usb_descriptor_header *) &rndis_qc_data_intf,
+	(struct usb_descriptor_header *) &rndis_qc_ss_in_desc,
+	(struct usb_descriptor_header *) &rndis_qc_ss_bulk_comp_desc,
+	(struct usb_descriptor_header *) &rndis_qc_ss_out_desc,
+	(struct usb_descriptor_header *) &rndis_qc_ss_bulk_comp_desc,
+	NULL,
+};
+
+/* string descriptors: */
+
+static struct usb_string rndis_qc_string_defs[] = {
+	[0].s = "RNDIS Communications Control",
+	[1].s = "RNDIS Ethernet Data",
+	[2].s = "RNDIS",
+	{  } /* end of list */
+};
+
+static struct usb_gadget_strings rndis_qc_string_table = {
+	.language =		0x0409,	/* en-us */
+	.strings =		rndis_qc_string_defs,
+};
+
+static struct usb_gadget_strings *rndis_qc_strings[] = {
+	&rndis_qc_string_table,
+	NULL,
+};
+
+struct f_rndis_qc *_rndis_qc;
+
+static inline int rndis_qc_lock(atomic_t *excl)
+{
+	if (atomic_inc_return(excl) == 1) {
+		return 0;
+	} else {
+		atomic_dec(excl);
+		return -EBUSY;
+	}
+}
+
+static inline void rndis_qc_unlock(atomic_t *excl)
+{
+	atomic_dec(excl);
+}
+
+/* MSM bam support */
+static struct data_port rndis_qc_bam_port;
+
+static int rndis_qc_bam_setup(void)
+{
+	int ret;
+
+	ret = bam_data_setup(RNDIS_QC_NO_PORTS);
+	if (ret) {
+		pr_err("bam_data_setup failed err: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rndis_qc_bam_connect(struct f_rndis_qc *dev)
+{
+	int ret;
+
+	rndis_qc_bam_port.func = dev->port.func;
+	rndis_qc_bam_port.in = dev->port.in_ep;
+	rndis_qc_bam_port.out = dev->port.out_ep;
+
+	/* currently we use the first connection */
+	ret = bam_data_connect(&rndis_qc_bam_port, 0, 0);
+	if (ret) {
+		pr_err("bam_data_connect failed: err:%d\n",
+				ret);
+		return ret;
+	} else {
+		pr_info("rndis bam connected\n");
+	}
+
+	return 0;
+}
+
+static int rndis_qc_bam_disconnect(struct f_rndis_qc *dev)
+{
+	pr_info("dev:%p. %s Do nothing.\n",
+			dev, __func__);
+
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct sk_buff *rndis_qc_add_header(struct qc_gether *port,
+					struct sk_buff *skb)
+{
+	struct sk_buff *skb2;
+
+	skb2 = skb_realloc_headroom(skb, sizeof(struct rndis_packet_msg_type));
+	if (skb2)
+		rndis_add_hdr(skb2);
+
+	dev_kfree_skb_any(skb);
+	return skb2;
+}
+
+int rndis_qc_rm_hdr(struct qc_gether *port,
+			struct sk_buff *skb,
+			struct sk_buff_head *list)
+{
+	/* tmp points to a struct rndis_packet_msg_type */
+	__le32 *tmp = (void *)skb->data;
+
+	/* MessageType, MessageLength */
+	if (cpu_to_le32(REMOTE_NDIS_PACKET_MSG)
+			!= get_unaligned(tmp++)) {
+		dev_kfree_skb_any(skb);
+		return -EINVAL;
+	}
+	tmp++;
+
+	/* DataOffset, DataLength */
+	if (!skb_pull(skb, get_unaligned_le32(tmp++) + 8)) {
+		dev_kfree_skb_any(skb);
+		return -EOVERFLOW;
+	}
+	skb_trim(skb, get_unaligned_le32(tmp++));
+
+	skb_queue_tail(list, skb);
+	return 0;
+}
+
+
+static void rndis_qc_response_available(void *_rndis)
+{
+	struct f_rndis_qc			*rndis = _rndis;
+	struct usb_request		*req = rndis->notify_req;
+	__le32				*data = req->buf;
+	int				status;
+
+	if (atomic_inc_return(&rndis->notify_count) != 1)
+		return;
+
+	/* Send RNDIS RESPONSE_AVAILABLE notification; a
+	 * USB_CDC_NOTIFY_RESPONSE_AVAILABLE "should" work too
+	 *
+	 * This is the only notification defined by RNDIS.
+	 */
+	data[0] = cpu_to_le32(1);
+	data[1] = cpu_to_le32(0);
+
+	status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
+	if (status) {
+		atomic_dec(&rndis->notify_count);
+		pr_info("notify/0 --> %d\n", status);
+	}
+}
+
+static void rndis_qc_response_complete(struct usb_ep *ep,
+						struct usb_request *req)
+{
+	struct f_rndis_qc			*rndis = req->context;
+	int				status = req->status;
+
+	/* after TX:
+	 *  - USB_CDC_GET_ENCAPSULATED_RESPONSE (ep0/control)
+	 *  - RNDIS_RESPONSE_AVAILABLE (status/irq)
+	 */
+	switch (status) {
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+		/* connection gone */
+		atomic_set(&rndis->notify_count, 0);
+		break;
+	default:
+		pr_info("RNDIS %s response error %d, %d/%d\n",
+			ep->name, status,
+			req->actual, req->length);
+		/* FALLTHROUGH */
+	case 0:
+		if (ep != rndis->notify)
+			break;
+
+		/* handle multiple pending RNDIS_RESPONSE_AVAILABLE
+		 * notifications by resending until we're done
+		 */
+		if (atomic_dec_and_test(&rndis->notify_count))
+			break;
+		status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
+		if (status) {
+			atomic_dec(&rndis->notify_count);
+			DBG(cdev, "notify/1 --> %d\n", status);
+		}
+		break;
+	}
+}
+
+static void rndis_qc_command_complete(struct usb_ep *ep,
+							struct usb_request *req)
+{
+	struct f_rndis_qc			*rndis = req->context;
+	int				status;
+
+	/* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
+	status = rndis_msg_parser(rndis->config, (u8 *) req->buf);
+	if (status < 0)
+		pr_err("RNDIS command error %d, %d/%d\n",
+			status, req->actual, req->length);
+}
+
+static int
+rndis_qc_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+	struct usb_request	*req = cdev->req;
+	int			value = -EOPNOTSUPP;
+	u16			w_index = le16_to_cpu(ctrl->wIndex);
+	u16			w_value = le16_to_cpu(ctrl->wValue);
+	u16			w_length = le16_to_cpu(ctrl->wLength);
+
+	/* composite driver infrastructure handles everything except
+	 * CDC class messages; interface activation uses set_alt().
+	 */
+	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
+
+	/* RNDIS uses the CDC command encapsulation mechanism to implement
+	 * an RPC scheme, with much getting/setting of attributes by OID.
+	 */
+	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+			| USB_CDC_SEND_ENCAPSULATED_COMMAND:
+		if (w_value || w_index != rndis->ctrl_id)
+			goto invalid;
+		/* read the request; process it later */
+		value = w_length;
+		req->complete = rndis_qc_command_complete;
+		req->context = rndis;
+		/* later, rndis_response_available() sends a notification */
+		break;
+
+	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
+			| USB_CDC_GET_ENCAPSULATED_RESPONSE:
+		if (w_value || w_index != rndis->ctrl_id)
+			goto invalid;
+		else {
+			u8 *buf;
+			u32 n;
+
+			/* return the result */
+			buf = rndis_get_next_response(rndis->config, &n);
+			if (buf) {
+				memcpy(req->buf, buf, n);
+				req->complete = rndis_qc_response_complete;
+				rndis_free_response(rndis->config, buf);
+				value = n;
+			}
+			/* else stalls ... spec says to avoid that */
+		}
+		break;
+
+	default:
+invalid:
+		VDBG(cdev, "invalid 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 or status phase? */
+	if (value >= 0) {
+		DBG(cdev, "rndis req%02x.%02x v%04x i%04x l%d\n",
+			ctrl->bRequestType, ctrl->bRequest,
+			w_value, w_index, w_length);
+		req->zero = (value < w_length);
+		req->length = value;
+		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+		if (value < 0)
+			pr_err("rndis response on err %d\n", value);
+	}
+
+	/* device either stalls (value < 0) or reports success */
+	return value;
+}
+
+
+static int rndis_qc_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	/* we know alt == 0 */
+
+	if (intf == rndis->ctrl_id) {
+		if (rndis->notify->driver_data) {
+			VDBG(cdev, "reset rndis control %d\n", intf);
+			usb_ep_disable(rndis->notify);
+		}
+		if (!rndis->notify->desc) {
+			VDBG(cdev, "init rndis ctrl %d\n", intf);
+			if (config_ep_by_speed(cdev->gadget, f, rndis->notify))
+				goto fail;
+		}
+		usb_ep_enable(rndis->notify);
+		rndis->notify->driver_data = rndis;
+
+	} else if (intf == rndis->data_id) {
+		struct net_device	*net;
+
+		if (rndis->port.in_ep->driver_data) {
+			DBG(cdev, "reset rndis\n");
+			gether_qc_disconnect(&rndis->port);
+			rndis_qc_bam_disconnect(rndis);
+		}
+
+		if (!rndis->port.in_ep->desc || !rndis->port.out_ep->desc) {
+			DBG(cdev, "init rndis\n");
+			if (config_ep_by_speed(cdev->gadget, f,
+					       rndis->port.in_ep) ||
+			    config_ep_by_speed(cdev->gadget, f,
+					       rndis->port.out_ep)) {
+				rndis->port.in_ep->desc = NULL;
+				rndis->port.out_ep->desc = NULL;
+				goto fail;
+			}
+		}
+
+		/* Avoid ZLPs; they can be troublesome. */
+		rndis->port.is_zlp_ok = false;
+
+		/* RNDIS should be in the "RNDIS uninitialized" state,
+		 * either never activated or after rndis_uninit().
+		 *
+		 * We don't want data to flow here until a nonzero packet
+		 * filter is set, at which point it enters "RNDIS data
+		 * initialized" state ... but we do want the endpoints
+		 * to be activated.  It's a strange little state.
+		 *
+		 * REVISIT the RNDIS gadget code has done this wrong for a
+		 * very long time.  We need another call to the link layer
+		 * code -- gether_updown(...bool) maybe -- to do it right.
+		 */
+		rndis->port.cdc_filter = 0;
+
+		DBG(cdev, "RNDIS RX/TX early activation ...\n");
+		net = gether_qc_connect(&rndis->port);
+		if (IS_ERR(net))
+			return PTR_ERR(net);
+
+		if (rndis_qc_bam_connect(rndis))
+			goto fail;
+
+		rndis_set_param_dev(rndis->config, net,
+				&rndis->port.cdc_filter);
+	} else
+		goto fail;
+
+	return 0;
+fail:
+	return -EINVAL;
+}
+
+static void rndis_qc_disable(struct usb_function *f)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
+
+	if (!rndis->notify->driver_data)
+		return;
+
+	pr_info("rndis deactivated\n");
+
+	rndis_uninit(rndis->config);
+	gether_qc_disconnect(&rndis->port);
+	rndis_qc_bam_disconnect(rndis);
+
+	usb_ep_disable(rndis->notify);
+	rndis->notify->driver_data = NULL;
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * This isn't quite the same mechanism as CDC Ethernet, since the
+ * notification scheme passes less data, but the same set of link
+ * states must be tested.  A key difference is that altsettings are
+ * not used to tell whether the link should send packets or not.
+ */
+
+static void rndis_qc_open(struct qc_gether *geth)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(&geth->func);
+	struct usb_composite_dev *cdev = geth->func.config->cdev;
+
+	DBG(cdev, "%s\n", __func__);
+
+	rndis_set_param_medium(rndis->config, NDIS_MEDIUM_802_3,
+				rndis_qc_bitrate(cdev->gadget) / 100);
+	rndis_signal_connect(rndis->config);
+}
+
+static void rndis_qc_close(struct qc_gether *geth)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(&geth->func);
+
+	DBG(geth->func.config->cdev, "%s\n", __func__);
+
+	rndis_set_param_medium(rndis->config, NDIS_MEDIUM_802_3, 0);
+	rndis_signal_disconnect(rndis->config);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* ethernet function driver setup/binding */
+
+static int
+rndis_qc_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
+	int			status;
+	struct usb_ep		*ep;
+
+	/* allocate instance-specific interface IDs */
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	rndis->ctrl_id = status;
+	rndis_qc_iad_descriptor.bFirstInterface = status;
+
+	rndis_qc_control_intf.bInterfaceNumber = status;
+	rndis_qc_union_desc.bMasterInterface0 = status;
+
+	status = usb_interface_id(c, f);
+	if (status < 0)
+		goto fail;
+	rndis->data_id = status;
+
+	rndis_qc_data_intf.bInterfaceNumber = status;
+	rndis_qc_union_desc.bSlaveInterface0 = status;
+
+	status = -ENODEV;
+
+	/* allocate instance-specific endpoints */
+	ep = usb_ep_autoconfig(cdev->gadget, &rndis_qc_fs_in_desc);
+	if (!ep)
+		goto fail;
+	rndis->port.in_ep = ep;
+	ep->driver_data = cdev;	/* claim */
+
+	ep = usb_ep_autoconfig(cdev->gadget, &rndis_qc_fs_out_desc);
+	if (!ep)
+		goto fail;
+	rndis->port.out_ep = ep;
+	ep->driver_data = cdev;	/* claim */
+
+	/* NOTE:  a status/notification endpoint is, strictly speaking,
+	 * optional.  We don't treat it that way though!  It's simpler,
+	 * and some newer profiles don't treat it as optional.
+	 */
+	ep = usb_ep_autoconfig(cdev->gadget, &rndis_qc_fs_notify_desc);
+	if (!ep)
+		goto fail;
+	rndis->notify = ep;
+	ep->driver_data = cdev;	/* claim */
+
+	status = -ENOMEM;
+
+	/* allocate notification request and buffer */
+	rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
+	if (!rndis->notify_req)
+		goto fail;
+	rndis->notify_req->buf = kmalloc(RNDIS_QC_STATUS_BYTECOUNT, GFP_KERNEL);
+	if (!rndis->notify_req->buf)
+		goto fail;
+	rndis->notify_req->length = RNDIS_QC_STATUS_BYTECOUNT;
+	rndis->notify_req->context = rndis;
+	rndis->notify_req->complete = rndis_qc_response_complete;
+
+	/* copy descriptors, and track endpoint copies */
+	f->descriptors = usb_copy_descriptors(eth_qc_fs_function);
+	if (!f->descriptors)
+		goto fail;
+
+	/* support all relevant hardware speeds... we expect that when
+	 * hardware is dual speed, all bulk-capable endpoints work at
+	 * both speeds
+	 */
+	if (gadget_is_dualspeed(c->cdev->gadget)) {
+		rndis_qc_hs_in_desc.bEndpointAddress =
+				rndis_qc_fs_in_desc.bEndpointAddress;
+		rndis_qc_hs_out_desc.bEndpointAddress =
+				rndis_qc_fs_out_desc.bEndpointAddress;
+		rndis_qc_hs_notify_desc.bEndpointAddress =
+				rndis_qc_fs_notify_desc.bEndpointAddress;
+
+		/* copy descriptors, and track endpoint copies */
+		f->hs_descriptors = usb_copy_descriptors(eth_qc_hs_function);
+
+		if (!f->hs_descriptors)
+			goto fail;
+	}
+
+	if (gadget_is_superspeed(c->cdev->gadget)) {
+		rndis_qc_ss_in_desc.bEndpointAddress =
+				rndis_qc_fs_in_desc.bEndpointAddress;
+		rndis_qc_ss_out_desc.bEndpointAddress =
+				rndis_qc_fs_out_desc.bEndpointAddress;
+		rndis_qc_ss_notify_desc.bEndpointAddress =
+				rndis_qc_fs_notify_desc.bEndpointAddress;
+
+		/* copy descriptors, and track endpoint copies */
+		f->ss_descriptors = usb_copy_descriptors(eth_qc_ss_function);
+		if (!f->ss_descriptors)
+			goto fail;
+	}
+
+	rndis->port.open = rndis_qc_open;
+	rndis->port.close = rndis_qc_close;
+
+	status = rndis_register(rndis_qc_response_available, rndis);
+	if (status < 0)
+		goto fail;
+	rndis->config = status;
+
+	rndis_set_param_medium(rndis->config, NDIS_MEDIUM_802_3, 0);
+	rndis_set_host_mac(rndis->config, rndis->ethaddr);
+
+	if (rndis_set_param_vendor(rndis->config, rndis->vendorID,
+				   rndis->manufacturer))
+			goto fail;
+
+	rndis_set_max_pkt_xfer(rndis->config, rndis->max_pkt_per_xfer);
+
+	/* NOTE:  all that is done without knowing or caring about
+	 * the network link ... which is unavailable to this code
+	 * until we're activated via set_alt().
+	 */
+
+	DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
+			gadget_is_superspeed(c->cdev->gadget) ? "super" :
+			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+			rndis->port.in_ep->name, rndis->port.out_ep->name,
+			rndis->notify->name);
+	return 0;
+
+fail:
+	if (gadget_is_superspeed(c->cdev->gadget) && f->ss_descriptors)
+		usb_free_descriptors(f->ss_descriptors);
+	if (gadget_is_dualspeed(c->cdev->gadget) && f->hs_descriptors)
+		usb_free_descriptors(f->hs_descriptors);
+	if (f->descriptors)
+		usb_free_descriptors(f->descriptors);
+
+	if (rndis->notify_req) {
+		kfree(rndis->notify_req->buf);
+		usb_ep_free_request(rndis->notify, rndis->notify_req);
+	}
+
+	/* we might as well release our claims on endpoints */
+	if (rndis->notify)
+		rndis->notify->driver_data = NULL;
+	if (rndis->port.out_ep->desc)
+		rndis->port.out_ep->driver_data = NULL;
+	if (rndis->port.in_ep->desc)
+		rndis->port.in_ep->driver_data = NULL;
+
+	pr_err("%s: can't bind, err %d\n", f->name, status);
+
+	return status;
+}
+
+static void
+rndis_qc_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_rndis_qc		*rndis = func_to_rndis_qc(f);
+
+	rndis_deregister(rndis->config);
+	rndis_exit();
+
+	if (gadget_is_dualspeed(c->cdev->gadget))
+		usb_free_descriptors(f->hs_descriptors);
+	usb_free_descriptors(f->descriptors);
+
+	kfree(rndis->notify_req->buf);
+	usb_ep_free_request(rndis->notify, rndis->notify_req);
+
+	kfree(rndis);
+}
+
+/* Some controllers can't support RNDIS ... */
+static inline bool can_support_rndis_qc(struct usb_configuration *c)
+{
+	/* everything else is *presumably* fine */
+	return true;
+}
+
+/**
+ * rndis_qc_bind_config - add RNDIS network link to a configuration
+ * @c: the configuration to support the network link
+ * @ethaddr: a buffer in which the ethernet address of the host side
+ *	side of the link was recorded
+ * Context: single threaded during gadget setup
+ *
+ * Returns zero on success, else negative errno.
+ *
+ * Caller must have called @gether_setup().  Caller is also responsible
+ * for calling @gether_cleanup() before module unload.
+ */
+int
+rndis_qc_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
+{
+	return rndis_qc_bind_config_vendor(c, ethaddr, 0, NULL, 1);
+}
+
+int
+rndis_qc_bind_config_vendor(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
+					 u32 vendorID, const char *manufacturer,
+					 u8 max_pkt_per_xfer)
+{
+	struct f_rndis_qc	*rndis;
+	int		status;
+
+	if (!can_support_rndis_qc(c) || !ethaddr)
+		return -EINVAL;
+
+	/* setup RNDIS itself */
+	status = rndis_init();
+	if (status < 0)
+		return status;
+
+	status = rndis_qc_bam_setup();
+	if (status) {
+		pr_err("bam setup failed");
+		return status;
+	}
+
+	/* maybe allocate device-global string IDs */
+	if (rndis_qc_string_defs[0].id == 0) {
+
+		/* control interface label */
+		status = usb_string_id(c->cdev);
+		if (status < 0)
+			return status;
+		rndis_qc_string_defs[0].id = status;
+		rndis_qc_control_intf.iInterface = status;
+
+		/* data interface label */
+		status = usb_string_id(c->cdev);
+		if (status < 0)
+			return status;
+		rndis_qc_string_defs[1].id = status;
+		rndis_qc_data_intf.iInterface = status;
+
+		/* IAD iFunction label */
+		status = usb_string_id(c->cdev);
+		if (status < 0)
+			return status;
+		rndis_qc_string_defs[2].id = status;
+		rndis_qc_iad_descriptor.iFunction = status;
+	}
+
+	/* allocate and initialize one new instance */
+	status = -ENOMEM;
+	rndis = kzalloc(sizeof *rndis, GFP_KERNEL);
+	if (!rndis)
+		goto fail;
+
+	memcpy(rndis->ethaddr, ethaddr, ETH_ALEN);
+	rndis->vendorID = vendorID;
+	rndis->manufacturer = manufacturer;
+
+	/* if max_pkt_per_xfer was not configured set to default value */
+	rndis->max_pkt_per_xfer =
+		max_pkt_per_xfer ? max_pkt_per_xfer : DEFAULT_MAX_PKT_PER_XFER;
+
+	/* RNDIS activates when the host changes this filter */
+	rndis->port.cdc_filter = 0;
+
+	/* RNDIS has special (and complex) framing */
+	rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
+	rndis->port.wrap = rndis_qc_add_header;
+	rndis->port.unwrap = rndis_qc_rm_hdr;
+
+	rndis->port.func.name = "rndis";
+	rndis->port.func.strings = rndis_qc_strings;
+	/* descriptors are per-instance copies */
+	rndis->port.func.bind = rndis_qc_bind;
+	rndis->port.func.unbind = rndis_qc_unbind;
+	rndis->port.func.set_alt = rndis_qc_set_alt;
+	rndis->port.func.setup = rndis_qc_setup;
+	rndis->port.func.disable = rndis_qc_disable;
+
+	_rndis_qc = rndis;
+
+	status = usb_add_function(c, &rndis->port.func);
+	if (status) {
+		kfree(rndis);
+fail:
+		rndis_exit();
+	}
+	return status;
+}
+
+static int rndis_qc_open_dev(struct inode *ip, struct file *fp)
+{
+	pr_info("Open rndis QC driver\n");
+
+	if (!_rndis_qc) {
+		pr_err("rndis_qc_dev not created yet\n");
+		return -ENODEV;
+	}
+
+	if (rndis_qc_lock(&_rndis_qc->open_excl)) {
+		pr_err("Already opened\n");
+		return -EBUSY;
+	}
+
+	fp->private_data = _rndis_qc;
+	pr_info("rndis QC file opened\n");
+
+	return 0;
+}
+
+static int rndis_qc_release_dev(struct inode *ip, struct file *fp)
+{
+	struct f_rndis_qc	*rndis = fp->private_data;
+
+	pr_info("Close rndis QC file");
+	rndis_qc_unlock(&rndis->open_excl);
+
+	return 0;
+}
+
+static long rndis_qc_ioctl(struct file *fp, unsigned cmd, unsigned long arg)
+{
+	struct f_rndis_qc	*rndis = fp->private_data;
+	int ret = 0;
+
+	pr_info("Received command %d", cmd);
+
+	if (rndis_qc_lock(&rndis->ioctl_excl))
+		return -EBUSY;
+
+	switch (cmd) {
+	case RNDIS_QC_GET_MAX_PKT_PER_XFER:
+		ret = copy_to_user((void __user *)arg,
+					&rndis->max_pkt_per_xfer,
+					sizeof(rndis->max_pkt_per_xfer));
+		if (ret) {
+			pr_err("copying to user space failed");
+			ret = -EFAULT;
+		}
+		pr_info("Sent max packets per xfer %d",
+				rndis->max_pkt_per_xfer);
+		break;
+	default:
+		pr_err("Unsupported IOCTL");
+		ret = -EINVAL;
+	}
+
+	rndis_qc_unlock(&rndis->ioctl_excl);
+
+	return ret;
+}
+
+static const struct file_operations rndis_qc_fops = {
+	.owner = THIS_MODULE,
+	.open = rndis_qc_open_dev,
+	.release = rndis_qc_release_dev,
+	.unlocked_ioctl	= rndis_qc_ioctl,
+};
+
+static struct miscdevice rndis_qc_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "android_rndis_qc",
+	.fops = &rndis_qc_fops,
+};
+
+static int rndis_qc_init(void)
+{
+	int ret;
+
+	pr_info("initialize rndis QC instance\n");
+
+	ret = misc_register(&rndis_qc_device);
+	if (ret)
+		pr_err("rndis QC driver failed to register");
+
+	return ret;
+}
+
+static void rndis_qc_cleanup(void)
+{
+	pr_info("rndis QC cleanup");
+
+	misc_deregister(&rndis_qc_device);
+	_rndis_qc = NULL;
+}
+
+
diff --git a/drivers/usb/gadget/rndis.c b/drivers/usb/gadget/rndis.c
index 16c4afb..e0520c7 100644
--- a/drivers/usb/gadget/rndis.c
+++ b/drivers/usb/gadget/rndis.c
@@ -585,8 +585,8 @@
 	resp->MinorVersion = cpu_to_le32(RNDIS_MINOR_VERSION);
 	resp->DeviceFlags = cpu_to_le32(RNDIS_DF_CONNECTIONLESS);
 	resp->Medium = cpu_to_le32(RNDIS_MEDIUM_802_3);
-	resp->MaxPacketsPerTransfer = cpu_to_le32(TX_SKB_HOLD_THRESHOLD);
-	resp->MaxTransferSize = cpu_to_le32(TX_SKB_HOLD_THRESHOLD *
+	resp->MaxPacketsPerTransfer = cpu_to_le32(params->max_pkt_per_xfer);
+	resp->MaxTransferSize = cpu_to_le32(params->max_pkt_per_xfer *
 		(params->dev->mtu
 		+ sizeof(struct ethhdr)
 		+ sizeof(struct rndis_packet_msg_type)
@@ -902,6 +902,8 @@
 			rndis_per_dev_params[i].used = 1;
 			rndis_per_dev_params[i].resp_avail = resp_avail;
 			rndis_per_dev_params[i].v = v;
+			rndis_per_dev_params[i].max_pkt_per_xfer =
+							TX_SKB_HOLD_THRESHOLD;
 			pr_debug("%s: configNr = %d\n", __func__, i);
 			return i;
 		}
@@ -955,6 +957,13 @@
 	return 0;
 }
 
+void rndis_set_max_pkt_xfer(u8 configNr, u8 max_pkt_per_xfer)
+{
+	pr_debug("%s:\n", __func__);
+
+	rndis_per_dev_params[configNr].max_pkt_per_xfer = max_pkt_per_xfer;
+}
+
 void rndis_add_hdr(struct sk_buff *skb)
 {
 	struct rndis_packet_msg_type *header;
diff --git a/drivers/usb/gadget/rndis.h b/drivers/usb/gadget/rndis.h
index 907c330..1f06c42 100644
--- a/drivers/usb/gadget/rndis.h
+++ b/drivers/usb/gadget/rndis.h
@@ -235,6 +235,7 @@
 	struct net_device	*dev;
 
 	u32			vendorID;
+	u8			max_pkt_per_xfer;
 	const char		*vendorDescr;
 	void			(*resp_avail)(void *v);
 	void			*v;