diff --git a/Documentation/devicetree/bindings/usb/gr-udc.txt b/Documentation/devicetree/bindings/usb/gr-udc.txt
new file mode 100644
index 0000000..0c5118f
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/gr-udc.txt
@@ -0,0 +1,28 @@
+USB Peripheral Controller driver for Aeroflex Gaisler GRUSBDC.
+
+The GRUSBDC USB Device Controller core is available in the GRLIB VHDL
+IP core library.
+
+Note: In the ordinary environment for the core, a Leon SPARC system,
+these properties are built from information in the AMBA plug&play.
+
+Required properties:
+
+- name : Should be "GAISLER_USBDC" or "01_021"
+
+- reg : Address and length of the register set for the device
+
+- interrupts : Interrupt numbers for this device
+
+Optional properties:
+
+- epobufsizes : An array of buffer sizes for OUT endpoints. If the property is
+	not present, or for endpoints outside of the array, 1024 is assumed by
+	the driver.
+
+- epibufsizes : An array of buffer sizes for IN endpoints. If the property is
+	not present, or for endpoints outside of the array, 1024 is assumed by
+	the driver.
+
+For further information look in the documentation for the GLIB IP core library:
+http://www.gaisler.com/products/grlib/grip.pdf
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index fbc5607..8154165 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -216,6 +216,13 @@
 	   Say "y" to link the driver statically, or "m" to build a
 	   dynamically linked module called "fotg210_udc".
 
+config USB_GR_UDC
+       tristate "Aeroflex Gaisler GRUSBDC USB Peripheral Controller Driver"
+       depends on HAS_DMA
+       help
+          Select this to support Aeroflex Gaisler GRUSBDC cores from the GRLIB
+	  VHDL IP core library.
+
 config USB_OMAP
 	tristate "OMAP USB Device Controller"
 	depends on ARCH_OMAP1
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 6cccdfe..5f150bc 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -35,6 +35,7 @@
 obj-$(CONFIG_USB_FUSB300)	+= fusb300_udc.o
 obj-$(CONFIG_USB_FOTG210_UDC)	+= fotg210-udc.o
 obj-$(CONFIG_USB_MV_U3D)	+= mv_u3d_core.o
+obj-$(CONFIG_USB_GR_UDC)	+= gr_udc.o
 
 # USB Functions
 usb_f_acm-y			:= f_acm.o
diff --git a/drivers/usb/gadget/gr_udc.c b/drivers/usb/gadget/gr_udc.c
new file mode 100644
index 0000000..5f9c659
--- /dev/null
+++ b/drivers/usb/gadget/gr_udc.c
@@ -0,0 +1,2242 @@
+/*
+ * USB Peripheral Controller driver for Aeroflex Gaisler GRUSBDC.
+ *
+ * 2013 (c) Aeroflex Gaisler AB
+ *
+ * This driver supports GRUSBDC USB Device Controller cores available in the
+ * GRLIB VHDL IP core library.
+ *
+ * Full documentation of the GRUSBDC core can be found here:
+ * http://www.gaisler.com/products/grlib/grip.pdf
+ *
+ * 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.
+ *
+ * Contributors:
+ * - Andreas Larsson <andreas@gaisler.com>
+ * - Marko Isomaki
+ */
+
+/*
+ * A GRUSBDC core can have up to 16 IN endpoints and 16 OUT endpoints each
+ * individually configurable to any of the four USB transfer types. This driver
+ * only supports cores in DMA mode.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include <asm/byteorder.h>
+
+#include "gr_udc.h"
+
+#define	DRIVER_NAME	"gr_udc"
+#define	DRIVER_DESC	"Aeroflex Gaisler GRUSBDC USB Peripheral Controller"
+
+static const char driver_name[] = DRIVER_NAME;
+static const char driver_desc[] = DRIVER_DESC;
+
+#define gr_read32(x) (ioread32be((x)))
+#define gr_write32(x, v) (iowrite32be((v), (x)))
+
+/* USB speed and corresponding string calculated from status register value */
+#define GR_SPEED(status) \
+	((status & GR_STATUS_SP) ? USB_SPEED_FULL : USB_SPEED_HIGH)
+#define GR_SPEED_STR(status) usb_speed_string(GR_SPEED(status))
+
+/* Size of hardware buffer calculated from epctrl register value */
+#define GR_BUFFER_SIZE(epctrl)					      \
+	((((epctrl) & GR_EPCTRL_BUFSZ_MASK) >> GR_EPCTRL_BUFSZ_POS) * \
+	 GR_EPCTRL_BUFSZ_SCALER)
+
+/* ---------------------------------------------------------------------- */
+/* Debug printout functionality */
+
+static const char * const gr_modestring[] = {"control", "iso", "bulk", "int"};
+
+static const char *gr_ep0state_string(enum gr_ep0state state)
+{
+	static const char *const names[] = {
+		[GR_EP0_DISCONNECT] = "disconnect",
+		[GR_EP0_SETUP] = "setup",
+		[GR_EP0_IDATA] = "idata",
+		[GR_EP0_ODATA] = "odata",
+		[GR_EP0_ISTATUS] = "istatus",
+		[GR_EP0_OSTATUS] = "ostatus",
+		[GR_EP0_STALL] = "stall",
+		[GR_EP0_SUSPEND] = "suspend",
+	};
+
+	if (state < 0 || state >= ARRAY_SIZE(names))
+		return "UNKNOWN";
+
+	return names[state];
+}
+
+#ifdef VERBOSE_DEBUG
+
+static void gr_dbgprint_request(const char *str, struct gr_ep *ep,
+				struct gr_request *req)
+{
+	int buflen = ep->is_in ? req->req.length : req->req.actual;
+	int rowlen = 32;
+	int plen = min(rowlen, buflen);
+
+	dev_dbg(ep->dev->dev, "%s: 0x%p, %d bytes data%s:\n", str, req, buflen,
+		(buflen > plen ? " (truncated)" : ""));
+	print_hex_dump_debug("   ", DUMP_PREFIX_NONE,
+			     rowlen, 4, req->req.buf, plen, false);
+}
+
+static void gr_dbgprint_devreq(struct gr_udc *dev, u8 type, u8 request,
+			       u16 value, u16 index, u16 length)
+{
+	dev_vdbg(dev->dev, "REQ: %02x.%02x v%04x i%04x l%04x\n",
+		 type, request, value, index, length);
+}
+#else /* !VERBOSE_DEBUG */
+
+static void gr_dbgprint_request(const char *str, struct gr_ep *ep,
+				struct gr_request *req) {}
+
+static void gr_dbgprint_devreq(struct gr_udc *dev, u8 type, u8 request,
+			       u16 value, u16 index, u16 length) {}
+
+#endif /* VERBOSE_DEBUG */
+
+/* ---------------------------------------------------------------------- */
+/* Debugfs functionality */
+
+#ifdef CONFIG_USB_GADGET_DEBUG_FS
+
+static void gr_seq_ep_show(struct seq_file *seq, struct gr_ep *ep)
+{
+	u32 epctrl = gr_read32(&ep->regs->epctrl);
+	u32 epstat = gr_read32(&ep->regs->epstat);
+	int mode = (epctrl & GR_EPCTRL_TT_MASK) >> GR_EPCTRL_TT_POS;
+	struct gr_request *req;
+
+	seq_printf(seq, "%s:\n", ep->ep.name);
+	seq_printf(seq, "  mode = %s\n", gr_modestring[mode]);
+	seq_printf(seq, "  halted: %d\n", !!(epctrl & GR_EPCTRL_EH));
+	seq_printf(seq, "  disabled: %d\n", !!(epctrl & GR_EPCTRL_ED));
+	seq_printf(seq, "  valid: %d\n", !!(epctrl & GR_EPCTRL_EV));
+	seq_printf(seq, "  dma_start = %d\n", ep->dma_start);
+	seq_printf(seq, "  stopped = %d\n", ep->stopped);
+	seq_printf(seq, "  wedged = %d\n", ep->wedged);
+	seq_printf(seq, "  callback = %d\n", ep->callback);
+	seq_printf(seq, "  maxpacket = %d\n", ep->ep.maxpacket);
+	seq_printf(seq, "  bytes_per_buffer = %d\n", ep->bytes_per_buffer);
+	if (mode == 1 || mode == 3)
+		seq_printf(seq, "  nt = %d\n",
+			   (epctrl & GR_EPCTRL_NT_MASK) >> GR_EPCTRL_NT_POS);
+
+	seq_printf(seq, "  Buffer 0: %s %s%d\n",
+		   epstat & GR_EPSTAT_B0 ? "valid" : "invalid",
+		   epstat & GR_EPSTAT_BS ? " " : "selected ",
+		   (epstat & GR_EPSTAT_B0CNT_MASK) >> GR_EPSTAT_B0CNT_POS);
+	seq_printf(seq, "  Buffer 1: %s %s%d\n",
+		   epstat & GR_EPSTAT_B1 ? "valid" : "invalid",
+		   epstat & GR_EPSTAT_BS ? "selected " : " ",
+		   (epstat & GR_EPSTAT_B1CNT_MASK) >> GR_EPSTAT_B1CNT_POS);
+
+	if (list_empty(&ep->queue)) {
+		seq_puts(seq, "  Queue: empty\n\n");
+		return;
+	}
+
+	seq_puts(seq, "  Queue:\n");
+	list_for_each_entry(req, &ep->queue, queue) {
+		struct gr_dma_desc *desc;
+		struct gr_dma_desc *next;
+
+		seq_printf(seq, "    0x%p: 0x%p %d %d\n", req,
+			   &req->req.buf, req->req.actual, req->req.length);
+
+		next = req->first_desc;
+		do {
+			desc = next;
+			next = desc->next_desc;
+			seq_printf(seq, "    %c 0x%p (0x%08x): 0x%05x 0x%08x\n",
+				   desc == req->curr_desc ? 'c' : ' ',
+				   desc, desc->paddr, desc->ctrl, desc->data);
+		} while (desc != req->last_desc);
+	}
+	seq_puts(seq, "\n");
+}
+
+
+static int gr_seq_show(struct seq_file *seq, void *v)
+{
+	struct gr_udc *dev = seq->private;
+	u32 control = gr_read32(&dev->regs->control);
+	u32 status = gr_read32(&dev->regs->status);
+	struct gr_ep *ep;
+
+	seq_printf(seq, "usb state = %s\n",
+		   usb_state_string(dev->gadget.state));
+	seq_printf(seq, "address = %d\n",
+		   (control & GR_CONTROL_UA_MASK) >> GR_CONTROL_UA_POS);
+	seq_printf(seq, "speed = %s\n", GR_SPEED_STR(status));
+	seq_printf(seq, "ep0state = %s\n", gr_ep0state_string(dev->ep0state));
+	seq_printf(seq, "irq_enabled = %d\n", dev->irq_enabled);
+	seq_printf(seq, "remote_wakeup = %d\n", dev->remote_wakeup);
+	seq_printf(seq, "test_mode = %d\n", dev->test_mode);
+	seq_puts(seq, "\n");
+
+	list_for_each_entry(ep, &dev->ep_list, ep_list)
+		gr_seq_ep_show(seq, ep);
+
+	return 0;
+}
+
+static int gr_dfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, gr_seq_show, inode->i_private);
+}
+
+static const struct file_operations gr_dfs_fops = {
+	.owner		= THIS_MODULE,
+	.open		= gr_dfs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void gr_dfs_create(struct gr_udc *dev)
+{
+	const char *name = "gr_udc_state";
+
+	dev->dfs_root = debugfs_create_dir(dev_name(dev->dev), NULL);
+	if (IS_ERR(dev->dfs_root)) {
+		dev_err(dev->dev, "Failed to create debugfs directory\n");
+		return;
+	}
+	dev->dfs_state = debugfs_create_file(name, 0444, dev->dfs_root,
+					     dev, &gr_dfs_fops);
+	if (IS_ERR(dev->dfs_state))
+		dev_err(dev->dev, "Failed to create debugfs file %s\n", name);
+}
+
+static void gr_dfs_delete(struct gr_udc *dev)
+{
+	/* Handles NULL and ERR pointers internally */
+	debugfs_remove(dev->dfs_state);
+	debugfs_remove(dev->dfs_root);
+}
+
+#else /* !CONFIG_USB_GADGET_DEBUG_FS */
+
+static void gr_dfs_create(struct gr_udc *dev) {}
+static void gr_dfs_delete(struct gr_udc *dev) {}
+
+#endif /* CONFIG_USB_GADGET_DEBUG_FS */
+
+/* ---------------------------------------------------------------------- */
+/* DMA and request handling */
+
+/* Allocates a new struct gr_dma_desc, sets paddr and zeroes the rest */
+static struct gr_dma_desc *gr_alloc_dma_desc(struct gr_ep *ep, gfp_t gfp_flags)
+{
+	dma_addr_t paddr;
+	struct gr_dma_desc *dma_desc;
+
+	dma_desc = dma_pool_alloc(ep->dev->desc_pool, gfp_flags, &paddr);
+	if (!dma_desc) {
+		dev_err(ep->dev->dev, "Could not allocate from DMA pool\n");
+		return NULL;
+	}
+
+	memset(dma_desc, 0, sizeof(*dma_desc));
+	dma_desc->paddr = paddr;
+
+	return dma_desc;
+}
+
+static inline void gr_free_dma_desc(struct gr_udc *dev,
+				    struct gr_dma_desc *desc)
+{
+	dma_pool_free(dev->desc_pool, desc, (dma_addr_t)desc->paddr);
+}
+
+/* Frees the chain of struct gr_dma_desc for the given request */
+static void gr_free_dma_desc_chain(struct gr_udc *dev, struct gr_request *req)
+{
+	struct gr_dma_desc *desc;
+	struct gr_dma_desc *next;
+
+	next = req->first_desc;
+	if (!next)
+		return;
+
+	do {
+		desc = next;
+		next = desc->next_desc;
+		gr_free_dma_desc(dev, desc);
+	} while (desc != req->last_desc);
+
+	req->first_desc = NULL;
+	req->curr_desc = NULL;
+	req->last_desc = NULL;
+}
+
+static void gr_ep0_setup(struct gr_udc *dev, struct gr_request *req);
+
+/*
+ * Frees allocated resources and calls the appropriate completion function/setup
+ * package handler for a finished request.
+ *
+ * Must be called with dev->lock held and irqs disabled.
+ */
+static void gr_finish_request(struct gr_ep *ep, struct gr_request *req,
+			      int status)
+	__releases(&dev->lock)
+	__acquires(&dev->lock)
+{
+	struct gr_udc *dev;
+
+	list_del_init(&req->queue);
+
+	if (likely(req->req.status == -EINPROGRESS))
+		req->req.status = status;
+	else
+		status = req->req.status;
+
+	dev = ep->dev;
+	usb_gadget_unmap_request(&dev->gadget, &req->req, ep->is_in);
+	gr_free_dma_desc_chain(dev, req);
+
+	if (ep->is_in) /* For OUT, actual gets updated bit by bit */
+		req->req.actual = req->req.length;
+
+	if (!status) {
+		if (ep->is_in)
+			gr_dbgprint_request("SENT", ep, req);
+		else
+			gr_dbgprint_request("RECV", ep, req);
+	}
+
+	/* Prevent changes to ep->queue during callback */
+	ep->callback = 1;
+	if (req == dev->ep0reqo && !status) {
+		if (req->setup)
+			gr_ep0_setup(dev, req);
+		else
+			dev_err(dev->dev,
+				"Unexpected non setup packet on ep0in\n");
+	} else if (req->req.complete) {
+		spin_unlock(&dev->lock);
+
+		req->req.complete(&ep->ep, &req->req);
+
+		spin_lock(&dev->lock);
+	}
+	ep->callback = 0;
+}
+
+static struct usb_request *gr_alloc_request(struct usb_ep *_ep, gfp_t gfp_flags)
+{
+	struct gr_request *req;
+
+	req = kzalloc(sizeof(*req), gfp_flags);
+	if (!req)
+		return NULL;
+
+	INIT_LIST_HEAD(&req->queue);
+
+	return &req->req;
+}
+
+/*
+ * Starts DMA for endpoint ep if there are requests in the queue.
+ *
+ * Must be called with dev->lock held and with !ep->stopped.
+ */
+static void gr_start_dma(struct gr_ep *ep)
+{
+	struct gr_request *req;
+	u32 dmactrl;
+
+	if (list_empty(&ep->queue)) {
+		ep->dma_start = 0;
+		return;
+	}
+
+	req = list_first_entry(&ep->queue, struct gr_request, queue);
+
+	/* A descriptor should already have been allocated */
+	BUG_ON(!req->curr_desc);
+
+	wmb(); /* Make sure all is settled before handing it over to DMA */
+
+	/* Set the descriptor pointer in the hardware */
+	gr_write32(&ep->regs->dmaaddr, req->curr_desc->paddr);
+
+	/* Announce available descriptors */
+	dmactrl = gr_read32(&ep->regs->dmactrl);
+	gr_write32(&ep->regs->dmactrl, dmactrl | GR_DMACTRL_DA);
+
+	ep->dma_start = 1;
+}
+
+/*
+ * Finishes the first request in the ep's queue and, if available, starts the
+ * next request in queue.
+ *
+ * Must be called with dev->lock held, irqs disabled and with !ep->stopped.
+ */
+static void gr_dma_advance(struct gr_ep *ep, int status)
+{
+	struct gr_request *req;
+
+	req = list_first_entry(&ep->queue, struct gr_request, queue);
+	gr_finish_request(ep, req, status);
+	gr_start_dma(ep); /* Regardless of ep->dma_start */
+}
+
+/*
+ * Abort DMA for an endpoint. Sets the abort DMA bit which causes an ongoing DMA
+ * transfer to be canceled and clears GR_DMACTRL_DA.
+ *
+ * Must be called with dev->lock held.
+ */
+static void gr_abort_dma(struct gr_ep *ep)
+{
+	u32 dmactrl;
+
+	dmactrl = gr_read32(&ep->regs->dmactrl);
+	gr_write32(&ep->regs->dmactrl, dmactrl | GR_DMACTRL_AD);
+}
+
+/*
+ * Allocates and sets up a struct gr_dma_desc and putting it on the descriptor
+ * chain.
+ *
+ * Size is not used for OUT endpoints. Hardware can not be instructed to handle
+ * smaller buffer than MAXPL in the OUT direction.
+ */
+static int gr_add_dma_desc(struct gr_ep *ep, struct gr_request *req,
+			   dma_addr_t data, unsigned size, gfp_t gfp_flags)
+{
+	struct gr_dma_desc *desc;
+
+	desc = gr_alloc_dma_desc(ep, gfp_flags);
+	if (!desc)
+		return -ENOMEM;
+
+	desc->data = data;
+	if (ep->is_in)
+		desc->ctrl =
+			(GR_DESC_IN_CTRL_LEN_MASK & size) | GR_DESC_IN_CTRL_EN;
+	else
+		desc->ctrl = GR_DESC_OUT_CTRL_IE;
+
+	if (!req->first_desc) {
+		req->first_desc = desc;
+		req->curr_desc = desc;
+	} else {
+		req->last_desc->next_desc = desc;
+		req->last_desc->next = desc->paddr;
+		req->last_desc->ctrl |= GR_DESC_OUT_CTRL_NX;
+	}
+	req->last_desc = desc;
+
+	return 0;
+}
+
+/*
+ * Sets up a chain of struct gr_dma_descriptors pointing to buffers that
+ * together covers req->req.length bytes of the buffer at DMA address
+ * req->req.dma for the OUT direction.
+ *
+ * The first descriptor in the chain is enabled, the rest disabled. The
+ * interrupt handler will later enable them one by one when needed so we can
+ * find out when the transfer is finished. For OUT endpoints, all descriptors
+ * therefore generate interrutps.
+ */
+static int gr_setup_out_desc_list(struct gr_ep *ep, struct gr_request *req,
+				  gfp_t gfp_flags)
+{
+	u16 bytes_left; /* Bytes left to provide descriptors for */
+	u16 bytes_used; /* Bytes accommodated for */
+	int ret = 0;
+
+	req->first_desc = NULL; /* Signals that no allocation is done yet */
+	bytes_left = req->req.length;
+	bytes_used = 0;
+	while (bytes_left > 0) {
+		dma_addr_t start = req->req.dma + bytes_used;
+		u16 size = min(bytes_left, ep->bytes_per_buffer);
+
+		/* Should not happen however - gr_queue stops such lengths */
+		if (size < ep->bytes_per_buffer)
+			dev_warn(ep->dev->dev,
+				 "Buffer overrun risk: %u < %u bytes/buffer\n",
+				 size, ep->bytes_per_buffer);
+
+		ret = gr_add_dma_desc(ep, req, start, size, gfp_flags);
+		if (ret)
+			goto alloc_err;
+
+		bytes_left -= size;
+		bytes_used += size;
+	}
+
+	req->first_desc->ctrl |= GR_DESC_OUT_CTRL_EN;
+
+	return 0;
+
+alloc_err:
+	gr_free_dma_desc_chain(ep->dev, req);
+
+	return ret;
+}
+
+/*
+ * Sets up a chain of struct gr_dma_descriptors pointing to buffers that
+ * together covers req->req.length bytes of the buffer at DMA address
+ * req->req.dma for the IN direction.
+ *
+ * When more data is provided than the maximum payload size, the hardware splits
+ * this up into several payloads automatically. Moreover, ep->bytes_per_buffer
+ * is always set to a multiple of the maximum payload (restricted to the valid
+ * number of maximum payloads during high bandwidth isochronous or interrupt
+ * transfers)
+ *
+ * All descriptors are enabled from the beginning and we only generate an
+ * interrupt for the last one indicating that the entire request has been pushed
+ * to hardware.
+ */
+static int gr_setup_in_desc_list(struct gr_ep *ep, struct gr_request *req,
+				 gfp_t gfp_flags)
+{
+	u16 bytes_left; /* Bytes left in req to provide descriptors for */
+	u16 bytes_used; /* Bytes in req accommodated for */
+	int ret = 0;
+
+	req->first_desc = NULL; /* Signals that no allocation is done yet */
+	bytes_left = req->req.length;
+	bytes_used = 0;
+	do { /* Allow for zero length packets */
+		dma_addr_t start = req->req.dma + bytes_used;
+		u16 size = min(bytes_left, ep->bytes_per_buffer);
+
+		ret = gr_add_dma_desc(ep, req, start, size, gfp_flags);
+		if (ret)
+			goto alloc_err;
+
+		bytes_left -= size;
+		bytes_used += size;
+	} while (bytes_left > 0);
+
+	/*
+	 * Send an extra zero length packet to indicate that no more data is
+	 * available when req->req.zero is set and the data length is even
+	 * multiples of ep->ep.maxpacket.
+	 */
+	if (req->req.zero && (req->req.length % ep->ep.maxpacket == 0)) {
+		ret = gr_add_dma_desc(ep, req, 0, 0, gfp_flags);
+		if (ret)
+			goto alloc_err;
+	}
+
+	/*
+	 * For IN packets we only want to know when the last packet has been
+	 * transmitted (not just put into internal buffers).
+	 */
+	req->last_desc->ctrl |= GR_DESC_IN_CTRL_PI;
+
+	return 0;
+
+alloc_err:
+	gr_free_dma_desc_chain(ep->dev, req);
+
+	return ret;
+}
+
+/* Must be called with dev->lock held */
+static int gr_queue(struct gr_ep *ep, struct gr_request *req, gfp_t gfp_flags)
+{
+	struct gr_udc *dev = ep->dev;
+	int ret;
+
+	if (unlikely(!ep->ep.desc && ep->num != 0)) {
+		dev_err(dev->dev, "No ep descriptor for %s\n", ep->ep.name);
+		return -EINVAL;
+	}
+
+	if (unlikely(!req->req.buf || !list_empty(&req->queue))) {
+		dev_err(dev->dev,
+			"Invalid request for %s: buf=%p list_empty=%d\n",
+			ep->ep.name, req->req.buf, list_empty(&req->queue));
+		return -EINVAL;
+	}
+
+	/*
+	 * The DMA controller can not handle smaller OUT buffers than
+	 * maxpacket. It could lead to buffer overruns if unexpectedly long
+	 * packet are received.
+	 */
+	if (!ep->is_in && (req->req.length % ep->ep.maxpacket) != 0) {
+		dev_err(dev->dev,
+			"OUT request length %d is not multiple of maxpacket\n",
+			req->req.length);
+		return -EMSGSIZE;
+	}
+
+	if (unlikely(!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)) {
+		dev_err(dev->dev, "-ESHUTDOWN");
+		return -ESHUTDOWN;
+	}
+
+	/* Can't touch registers when suspended */
+	if (dev->ep0state == GR_EP0_SUSPEND) {
+		dev_err(dev->dev, "-EBUSY");
+		return -EBUSY;
+	}
+
+	/* Set up DMA mapping in case the caller didn't */
+	ret = usb_gadget_map_request(&dev->gadget, &req->req, ep->is_in);
+	if (ret) {
+		dev_err(dev->dev, "usb_gadget_map_request");
+		return ret;
+	}
+
+	if (ep->is_in)
+		ret = gr_setup_in_desc_list(ep, req, gfp_flags);
+	else
+		ret = gr_setup_out_desc_list(ep, req, gfp_flags);
+	if (ret)
+		return ret;
+
+	req->req.status = -EINPROGRESS;
+	req->req.actual = 0;
+	list_add_tail(&req->queue, &ep->queue);
+
+	/* Start DMA if not started, otherwise interrupt handler handles it */
+	if (!ep->dma_start && likely(!ep->stopped))
+		gr_start_dma(ep);
+
+	return 0;
+}
+
+/*
+ * Queue a request from within the driver.
+ *
+ * Must be called with dev->lock held.
+ */
+static inline int gr_queue_int(struct gr_ep *ep, struct gr_request *req,
+			       gfp_t gfp_flags)
+{
+	if (ep->is_in)
+		gr_dbgprint_request("RESP", ep, req);
+
+	return gr_queue(ep, req, gfp_flags);
+}
+
+/* ---------------------------------------------------------------------- */
+/* General helper functions */
+
+/*
+ * Dequeue ALL requests.
+ *
+ * Must be called with dev->lock held and irqs disabled.
+ */
+static void gr_ep_nuke(struct gr_ep *ep)
+{
+	struct gr_request *req;
+	struct gr_udc *dev;
+
+	dev = ep->dev;
+
+	ep->stopped = 1;
+	ep->dma_start = 0;
+	gr_abort_dma(ep);
+
+	while (!list_empty(&ep->queue)) {
+		req = list_first_entry(&ep->queue, struct gr_request, queue);
+		gr_finish_request(ep, req, -ESHUTDOWN);
+	}
+}
+
+/*
+ * Reset the hardware state of this endpoint.
+ *
+ * Must be called with dev->lock held.
+ */
+static void gr_ep_reset(struct gr_ep *ep)
+{
+	gr_write32(&ep->regs->epctrl, 0);
+	gr_write32(&ep->regs->dmactrl, 0);
+
+	ep->ep.maxpacket = MAX_CTRL_PL_SIZE;
+	ep->ep.desc = NULL;
+	ep->stopped = 1;
+	ep->dma_start = 0;
+}
+
+/*
+ * Generate STALL on ep0in/out.
+ *
+ * Must be called with dev->lock held.
+ */
+static void gr_control_stall(struct gr_udc *dev)
+{
+	u32 epctrl;
+
+	epctrl = gr_read32(&dev->epo[0].regs->epctrl);
+	gr_write32(&dev->epo[0].regs->epctrl, epctrl | GR_EPCTRL_CS);
+	epctrl = gr_read32(&dev->epi[0].regs->epctrl);
+	gr_write32(&dev->epi[0].regs->epctrl, epctrl | GR_EPCTRL_CS);
+
+	dev->ep0state = GR_EP0_STALL;
+}
+
+/*
+ * Halts, halts and wedges, or clears halt for an endpoint.
+ *
+ * Must be called with dev->lock held.
+ */
+static int gr_ep_halt_wedge(struct gr_ep *ep, int halt, int wedge, int fromhost)
+{
+	u32 epctrl;
+	int retval = 0;
+
+	if (ep->num && !ep->ep.desc)
+		return -EINVAL;
+
+	if (ep->num && ep->ep.desc->bmAttributes == USB_ENDPOINT_XFER_ISOC)
+		return -EOPNOTSUPP;
+
+	/* Never actually halt ep0, and therefore never clear halt for ep0 */
+	if (!ep->num) {
+		if (halt && !fromhost) {
+			/* ep0 halt from gadget - generate protocol stall */
+			gr_control_stall(ep->dev);
+			dev_dbg(ep->dev->dev, "EP: stall ep0\n");
+			return 0;
+		}
+		return -EINVAL;
+	}
+
+	dev_dbg(ep->dev->dev, "EP: %s halt %s\n",
+		(halt ? (wedge ? "wedge" : "set") : "clear"), ep->ep.name);
+
+	epctrl = gr_read32(&ep->regs->epctrl);
+	if (halt) {
+		/* Set HALT */
+		gr_write32(&ep->regs->epctrl, epctrl | GR_EPCTRL_EH);
+		ep->stopped = 1;
+		if (wedge)
+			ep->wedged = 1;
+	} else {
+		gr_write32(&ep->regs->epctrl, epctrl & ~GR_EPCTRL_EH);
+		ep->stopped = 0;
+		ep->wedged = 0;
+
+		/* Things might have been queued up in the meantime */
+		if (!ep->dma_start)
+			gr_start_dma(ep);
+	}
+
+	return retval;
+}
+
+/* Must be called with dev->lock held */
+static inline void gr_set_ep0state(struct gr_udc *dev, enum gr_ep0state value)
+{
+	if (dev->ep0state != value)
+		dev_vdbg(dev->dev, "STATE:  ep0state=%s\n",
+			 gr_ep0state_string(value));
+	dev->ep0state = value;
+}
+
+/*
+ * Should only be called when endpoints can not generate interrupts.
+ *
+ * Must be called with dev->lock held.
+ */
+static void gr_disable_interrupts_and_pullup(struct gr_udc *dev)
+{
+	gr_write32(&dev->regs->control, 0);
+	wmb(); /* Make sure that we do not deny one of our interrupts */
+	dev->irq_enabled = 0;
+}
+
+/*
+ * Stop all device activity and disable data line pullup.
+ *
+ * Must be called with dev->lock held and irqs disabled.
+ */
+static void gr_stop_activity(struct gr_udc *dev)
+{
+	struct gr_ep *ep;
+
+	list_for_each_entry(ep, &dev->ep_list, ep_list)
+		gr_ep_nuke(ep);
+
+	gr_disable_interrupts_and_pullup(dev);
+
+	gr_set_ep0state(dev, GR_EP0_DISCONNECT);
+	usb_gadget_set_state(&dev->gadget, USB_STATE_NOTATTACHED);
+}
+
+/* ---------------------------------------------------------------------- */
+/* ep0 setup packet handling */
+
+static void gr_ep0_testmode_complete(struct usb_ep *_ep,
+				     struct usb_request *_req)
+{
+	struct gr_ep *ep;
+	struct gr_udc *dev;
+	u32 control;
+
+	ep = container_of(_ep, struct gr_ep, ep);
+	dev = ep->dev;
+
+	spin_lock(&dev->lock);
+
+	control = gr_read32(&dev->regs->control);
+	control |= GR_CONTROL_TM | (dev->test_mode << GR_CONTROL_TS_POS);
+	gr_write32(&dev->regs->control, control);
+
+	spin_unlock(&dev->lock);
+}
+
+static void gr_ep0_dummy_complete(struct usb_ep *_ep, struct usb_request *_req)
+{
+	/* Nothing needs to be done here */
+}
+
+/*
+ * Queue a response on ep0in.
+ *
+ * Must be called with dev->lock held.
+ */
+static int gr_ep0_respond(struct gr_udc *dev, u8 *buf, int length,
+			  void (*complete)(struct usb_ep *ep,
+					   struct usb_request *req))
+{
+	u8 *reqbuf = dev->ep0reqi->req.buf;
+	int status;
+	int i;
+
+	for (i = 0; i < length; i++)
+		reqbuf[i] = buf[i];
+	dev->ep0reqi->req.length = length;
+	dev->ep0reqi->req.complete = complete;
+
+	status = gr_queue_int(&dev->epi[0], dev->ep0reqi, GFP_ATOMIC);
+	if (status < 0)
+		dev_err(dev->dev,
+			"Could not queue ep0in setup response: %d\n", status);
+
+	return status;
+}
+
+/*
+ * Queue a 2 byte response on ep0in.
+ *
+ * Must be called with dev->lock held.
+ */
+static inline int gr_ep0_respond_u16(struct gr_udc *dev, u16 response)
+{
+	__le16 le_response = cpu_to_le16(response);
+
+	return gr_ep0_respond(dev, (u8 *)&le_response, 2,
+			      gr_ep0_dummy_complete);
+}
+
+/*
+ * Queue a ZLP response on ep0in.
+ *
+ * Must be called with dev->lock held.
+ */
+static inline int gr_ep0_respond_empty(struct gr_udc *dev)
+{
+	return gr_ep0_respond(dev, NULL, 0, gr_ep0_dummy_complete);
+}
+
+/*
+ * This is run when a SET_ADDRESS request is received. First writes
+ * the new address to the control register which is updated internally
+ * when the next IN packet is ACKED.
+ *
+ * Must be called with dev->lock held.
+ */
+static void gr_set_address(struct gr_udc *dev, u8 address)
+{
+	u32 control;
+
+	control = gr_read32(&dev->regs->control) & ~GR_CONTROL_UA_MASK;
+	control |= (address << GR_CONTROL_UA_POS) & GR_CONTROL_UA_MASK;
+	control |= GR_CONTROL_SU;
+	gr_write32(&dev->regs->control, control);
+}
+
+/*
+ * Returns negative for STALL, 0 for successful handling and positive for
+ * delegation.
+ *
+ * Must be called with dev->lock held.
+ */
+static int gr_device_request(struct gr_udc *dev, u8 type, u8 request,
+			     u16 value, u16 index)
+{
+	u16 response;
+	u8 test;
+
+	switch (request) {
+	case USB_REQ_SET_ADDRESS:
+		dev_dbg(dev->dev, "STATUS: address %d\n", value & 0xff);
+		gr_set_address(dev, value & 0xff);
+		if (value)
+			usb_gadget_set_state(&dev->gadget, USB_STATE_ADDRESS);
+		else
+			usb_gadget_set_state(&dev->gadget, USB_STATE_DEFAULT);
+		return gr_ep0_respond_empty(dev);
+
+	case USB_REQ_GET_STATUS:
+		/* Self powered | remote wakeup */
+		response = 0x0001 | (dev->remote_wakeup ? 0x0002 : 0);
+		return gr_ep0_respond_u16(dev, response);
+
+	case USB_REQ_SET_FEATURE:
+		switch (value) {
+		case USB_DEVICE_REMOTE_WAKEUP:
+			/* Allow remote wakeup */
+			dev->remote_wakeup = 1;
+			return gr_ep0_respond_empty(dev);
+
+		case USB_DEVICE_TEST_MODE:
+			/* The hardware does not support TEST_FORCE_EN */
+			test = index >> 8;
+			if (test >= TEST_J && test <= TEST_PACKET) {
+				dev->test_mode = test;
+				return gr_ep0_respond(dev, NULL, 0,
+						      gr_ep0_testmode_complete);
+			}
+		}
+		break;
+
+	case USB_REQ_CLEAR_FEATURE:
+		switch (value) {
+		case USB_DEVICE_REMOTE_WAKEUP:
+			/* Disallow remote wakeup */
+			dev->remote_wakeup = 0;
+			return gr_ep0_respond_empty(dev);
+		}
+		break;
+	}
+
+	return 1; /* Delegate the rest */
+}
+
+/*
+ * Returns negative for STALL, 0 for successful handling and positive for
+ * delegation.
+ *
+ * Must be called with dev->lock held.
+ */
+static int gr_interface_request(struct gr_udc *dev, u8 type, u8 request,
+				u16 value, u16 index)
+{
+	if (dev->gadget.state != USB_STATE_CONFIGURED)
+		return -1;
+
+	/*
+	 * Should return STALL for invalid interfaces, but udc driver does not
+	 * know anything about that. However, many gadget drivers do not handle
+	 * GET_STATUS so we need to take care of that.
+	 */
+
+	switch (request) {
+	case USB_REQ_GET_STATUS:
+		return gr_ep0_respond_u16(dev, 0x0000);
+
+	case USB_REQ_SET_FEATURE:
+	case USB_REQ_CLEAR_FEATURE:
+		/*
+		 * No possible valid standard requests. Still let gadget drivers
+		 * have a go at it.
+		 */
+		break;
+	}
+
+	return 1; /* Delegate the rest */
+}
+
+/*
+ * Returns negative for STALL, 0 for successful handling and positive for
+ * delegation.
+ *
+ * Must be called with dev->lock held.
+ */
+static int gr_endpoint_request(struct gr_udc *dev, u8 type, u8 request,
+			       u16 value, u16 index)
+{
+	struct gr_ep *ep;
+	int status;
+	int halted;
+	u8 epnum = index & USB_ENDPOINT_NUMBER_MASK;
+	u8 is_in = index & USB_ENDPOINT_DIR_MASK;
+
+	if ((is_in && epnum >= dev->nepi) || (!is_in && epnum >= dev->nepo))
+		return -1;
+
+	if (dev->gadget.state != USB_STATE_CONFIGURED && epnum != 0)
+		return -1;
+
+	ep = (is_in ? &dev->epi[epnum] : &dev->epo[epnum]);
+
+	switch (request) {
+	case USB_REQ_GET_STATUS:
+		halted = gr_read32(&ep->regs->epctrl) & GR_EPCTRL_EH;
+		return gr_ep0_respond_u16(dev, halted ? 0x0001 : 0);
+
+	case USB_REQ_SET_FEATURE:
+		switch (value) {
+		case USB_ENDPOINT_HALT:
+			status = gr_ep_halt_wedge(ep, 1, 0, 1);
+			if (status >= 0)
+				status = gr_ep0_respond_empty(dev);
+			return status;
+		}
+		break;
+
+	case USB_REQ_CLEAR_FEATURE:
+		switch (value) {
+		case USB_ENDPOINT_HALT:
+			if (ep->wedged)
+				return -1;
+			status = gr_ep_halt_wedge(ep, 0, 0, 1);
+			if (status >= 0)
+				status = gr_ep0_respond_empty(dev);
+			return status;
+		}
+		break;
+	}
+
+	return 1; /* Delegate the rest */
+}
+
+/* Must be called with dev->lock held */
+static void gr_ep0out_requeue(struct gr_udc *dev)
+{
+	int ret = gr_queue_int(&dev->epo[0], dev->ep0reqo, GFP_ATOMIC);
+
+	if (ret)
+		dev_err(dev->dev, "Could not queue ep0out setup request: %d\n",
+			ret);
+}
+
+/*
+ * The main function dealing with setup requests on ep0.
+ *
+ * Must be called with dev->lock held and irqs disabled
+ */
+static void gr_ep0_setup(struct gr_udc *dev, struct gr_request *req)
+	__releases(&dev->lock)
+	__acquires(&dev->lock)
+{
+	union {
+		struct usb_ctrlrequest ctrl;
+		u8 raw[8];
+		u32 word[2];
+	} u;
+	u8 type;
+	u8 request;
+	u16 value;
+	u16 index;
+	u16 length;
+	int i;
+	int status;
+
+	/* Restore from ep0 halt */
+	if (dev->ep0state == GR_EP0_STALL) {
+		gr_set_ep0state(dev, GR_EP0_SETUP);
+		if (!req->req.actual)
+			goto out;
+	}
+
+	if (dev->ep0state == GR_EP0_ISTATUS) {
+		gr_set_ep0state(dev, GR_EP0_SETUP);
+		if (req->req.actual > 0)
+			dev_dbg(dev->dev,
+				"Unexpected setup packet at state %s\n",
+				gr_ep0state_string(GR_EP0_ISTATUS));
+		else
+			goto out; /* Got expected ZLP */
+	} else if (dev->ep0state != GR_EP0_SETUP) {
+		dev_info(dev->dev,
+			 "Unexpected ep0out request at state %s - stalling\n",
+			 gr_ep0state_string(dev->ep0state));
+		gr_control_stall(dev);
+		gr_set_ep0state(dev, GR_EP0_SETUP);
+		goto out;
+	} else if (!req->req.actual) {
+		dev_dbg(dev->dev, "Unexpected ZLP at state %s\n",
+			gr_ep0state_string(dev->ep0state));
+		goto out;
+	}
+
+	/* Handle SETUP packet */
+	for (i = 0; i < req->req.actual; i++)
+		u.raw[i] = ((u8 *)req->req.buf)[i];
+
+	type = u.ctrl.bRequestType;
+	request = u.ctrl.bRequest;
+	value = le16_to_cpu(u.ctrl.wValue);
+	index = le16_to_cpu(u.ctrl.wIndex);
+	length = le16_to_cpu(u.ctrl.wLength);
+
+	gr_dbgprint_devreq(dev, type, request, value, index, length);
+
+	/* Check for data stage */
+	if (length) {
+		if (type & USB_DIR_IN)
+			gr_set_ep0state(dev, GR_EP0_IDATA);
+		else
+			gr_set_ep0state(dev, GR_EP0_ODATA);
+	}
+
+	status = 1; /* Positive status flags delegation */
+	if ((type & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
+		switch (type & USB_RECIP_MASK) {
+		case USB_RECIP_DEVICE:
+			status = gr_device_request(dev, type, request,
+						   value, index);
+			break;
+		case USB_RECIP_ENDPOINT:
+			status =  gr_endpoint_request(dev, type, request,
+						      value, index);
+			break;
+		case USB_RECIP_INTERFACE:
+			status = gr_interface_request(dev, type, request,
+						      value, index);
+			break;
+		}
+	}
+
+	if (status > 0) {
+		spin_unlock(&dev->lock);
+
+		dev_vdbg(dev->dev, "DELEGATE\n");
+		status = dev->driver->setup(&dev->gadget, &u.ctrl);
+
+		spin_lock(&dev->lock);
+	}
+
+	/* Generate STALL on both ep0out and ep0in if requested */
+	if (unlikely(status < 0)) {
+		dev_vdbg(dev->dev, "STALL\n");
+		gr_control_stall(dev);
+	}
+
+	if ((type & USB_TYPE_MASK) == USB_TYPE_STANDARD &&
+	    request == USB_REQ_SET_CONFIGURATION) {
+		if (!value) {
+			dev_dbg(dev->dev, "STATUS: deconfigured\n");
+			usb_gadget_set_state(&dev->gadget, USB_STATE_ADDRESS);
+		} else if (status >= 0) {
+			/* Not configured unless gadget OK:s it */
+			dev_dbg(dev->dev, "STATUS: configured: %d\n", value);
+			usb_gadget_set_state(&dev->gadget,
+					     USB_STATE_CONFIGURED);
+		}
+	}
+
+	/* Get ready for next stage */
+	if (dev->ep0state == GR_EP0_ODATA)
+		gr_set_ep0state(dev, GR_EP0_OSTATUS);
+	else if (dev->ep0state == GR_EP0_IDATA)
+		gr_set_ep0state(dev, GR_EP0_ISTATUS);
+	else
+		gr_set_ep0state(dev, GR_EP0_SETUP);
+
+out:
+	gr_ep0out_requeue(dev);
+}
+
+/* ---------------------------------------------------------------------- */
+/* VBUS and USB reset handling */
+
+/* Must be called with dev->lock held and irqs disabled  */
+static void gr_vbus_connected(struct gr_udc *dev, u32 status)
+{
+	u32 control;
+
+	dev->gadget.speed = GR_SPEED(status);
+	usb_gadget_set_state(&dev->gadget, USB_STATE_POWERED);
+
+	/* Turn on full interrupts and pullup */
+	control = (GR_CONTROL_SI | GR_CONTROL_UI | GR_CONTROL_VI |
+		   GR_CONTROL_SP | GR_CONTROL_EP);
+	gr_write32(&dev->regs->control, control);
+}
+
+/* Must be called with dev->lock held */
+static void gr_enable_vbus_detect(struct gr_udc *dev)
+{
+	u32 status;
+
+	dev->irq_enabled = 1;
+	wmb(); /* Make sure we do not ignore an interrupt */
+	gr_write32(&dev->regs->control, GR_CONTROL_VI);
+
+	/* Take care of the case we are already plugged in at this point */
+	status = gr_read32(&dev->regs->status);
+	if (status & GR_STATUS_VB)
+		gr_vbus_connected(dev, status);
+}
+
+/* Must be called with dev->lock held and irqs disabled */
+static void gr_vbus_disconnected(struct gr_udc *dev)
+{
+	gr_stop_activity(dev);
+
+	/* Report disconnect */
+	if (dev->driver && dev->driver->disconnect) {
+		spin_unlock(&dev->lock);
+
+		dev->driver->disconnect(&dev->gadget);
+
+		spin_lock(&dev->lock);
+	}
+
+	gr_enable_vbus_detect(dev);
+}
+
+/* Must be called with dev->lock held and irqs disabled */
+static void gr_udc_usbreset(struct gr_udc *dev, u32 status)
+{
+	gr_set_address(dev, 0);
+	gr_set_ep0state(dev, GR_EP0_SETUP);
+	usb_gadget_set_state(&dev->gadget, USB_STATE_DEFAULT);
+	dev->gadget.speed = GR_SPEED(status);
+
+	gr_ep_nuke(&dev->epo[0]);
+	gr_ep_nuke(&dev->epi[0]);
+	dev->epo[0].stopped = 0;
+	dev->epi[0].stopped = 0;
+	gr_ep0out_requeue(dev);
+}
+
+/* ---------------------------------------------------------------------- */
+/* Irq handling */
+
+/*
+ * Handles interrupts from in endpoints. Returns whether something was handled.
+ *
+ * Must be called with dev->lock held, irqs disabled and with !ep->stopped.
+ */
+static int gr_handle_in_ep(struct gr_ep *ep)
+{
+	struct gr_request *req;
+
+	req = list_first_entry(&ep->queue, struct gr_request, queue);
+	if (!req->last_desc)
+		return 0;
+
+	if (ACCESS_ONCE(req->last_desc->ctrl) & GR_DESC_IN_CTRL_EN)
+		return 0; /* Not put in hardware buffers yet */
+
+	if (gr_read32(&ep->regs->epstat) & (GR_EPSTAT_B1 | GR_EPSTAT_B0))
+		return 0; /* Not transmitted yet, still in hardware buffers */
+
+	/* Write complete */
+	gr_dma_advance(ep, 0);
+
+	return 1;
+}
+
+/*
+ * Handles interrupts from out endpoints. Returns whether something was handled.
+ *
+ * Must be called with dev->lock held, irqs disabled and with !ep->stopped.
+ */
+static int gr_handle_out_ep(struct gr_ep *ep)
+{
+	u32 ep_dmactrl;
+	u32 ctrl;
+	u16 len;
+	struct gr_request *req;
+	struct gr_udc *dev = ep->dev;
+
+	req = list_first_entry(&ep->queue, struct gr_request, queue);
+	if (!req->curr_desc)
+		return 0;
+
+	ctrl = ACCESS_ONCE(req->curr_desc->ctrl);
+	if (ctrl & GR_DESC_OUT_CTRL_EN)
+		return 0; /* Not received yet */
+
+	/* Read complete */
+	len = ctrl & GR_DESC_OUT_CTRL_LEN_MASK;
+	req->req.actual += len;
+	if (ctrl & GR_DESC_OUT_CTRL_SE)
+		req->setup = 1;
+
+	if (len < ep->ep.maxpacket || req->req.actual == req->req.length) {
+		/* Short packet or the expected size - we are done */
+
+		if ((ep == &dev->epo[0]) && (dev->ep0state == GR_EP0_OSTATUS)) {
+			/*
+			 * Send a status stage ZLP to ack the DATA stage in the
+			 * OUT direction. This needs to be done before
+			 * gr_dma_advance as that can lead to a call to
+			 * ep0_setup that can change dev->ep0state.
+			 */
+			gr_ep0_respond_empty(dev);
+			gr_set_ep0state(dev, GR_EP0_SETUP);
+		}
+
+		gr_dma_advance(ep, 0);
+	} else {
+		/* Not done yet. Enable the next descriptor to receive more. */
+		req->curr_desc = req->curr_desc->next_desc;
+		req->curr_desc->ctrl |= GR_DESC_OUT_CTRL_EN;
+
+		ep_dmactrl = gr_read32(&ep->regs->dmactrl);
+		gr_write32(&ep->regs->dmactrl, ep_dmactrl | GR_DMACTRL_DA);
+	}
+
+	return 1;
+}
+
+/*
+ * Handle state changes. Returns whether something was handled.
+ *
+ * Must be called with dev->lock held and irqs disabled.
+ */
+static int gr_handle_state_changes(struct gr_udc *dev)
+{
+	u32 status = gr_read32(&dev->regs->status);
+	int handled = 0;
+	int powstate = !(dev->gadget.state == USB_STATE_NOTATTACHED ||
+			 dev->gadget.state == USB_STATE_ATTACHED);
+
+	/* VBUS valid detected */
+	if (!powstate && (status & GR_STATUS_VB)) {
+		dev_dbg(dev->dev, "STATUS: vbus valid detected\n");
+		gr_vbus_connected(dev, status);
+		handled = 1;
+	}
+
+	/* Disconnect */
+	if (powstate && !(status & GR_STATUS_VB)) {
+		dev_dbg(dev->dev, "STATUS: vbus invalid detected\n");
+		gr_vbus_disconnected(dev);
+		handled = 1;
+	}
+
+	/* USB reset detected */
+	if (status & GR_STATUS_UR) {
+		dev_dbg(dev->dev, "STATUS: USB reset - speed is %s\n",
+			GR_SPEED_STR(status));
+		gr_write32(&dev->regs->status, GR_STATUS_UR);
+		gr_udc_usbreset(dev, status);
+		handled = 1;
+	}
+
+	/* Speed change */
+	if (dev->gadget.speed != GR_SPEED(status)) {
+		dev_dbg(dev->dev, "STATUS: USB Speed change to %s\n",
+			GR_SPEED_STR(status));
+		dev->gadget.speed = GR_SPEED(status);
+		handled = 1;
+	}
+
+	/* Going into suspend */
+	if ((dev->ep0state != GR_EP0_SUSPEND) && !(status & GR_STATUS_SU)) {
+		dev_dbg(dev->dev, "STATUS: USB suspend\n");
+		gr_set_ep0state(dev, GR_EP0_SUSPEND);
+		dev->suspended_from = dev->gadget.state;
+		usb_gadget_set_state(&dev->gadget, USB_STATE_SUSPENDED);
+
+		if ((dev->gadget.speed != USB_SPEED_UNKNOWN) &&
+		    dev->driver && dev->driver->suspend) {
+			spin_unlock(&dev->lock);
+
+			dev->driver->suspend(&dev->gadget);
+
+			spin_lock(&dev->lock);
+		}
+		handled = 1;
+	}
+
+	/* Coming out of suspend */
+	if ((dev->ep0state == GR_EP0_SUSPEND) && (status & GR_STATUS_SU)) {
+		dev_dbg(dev->dev, "STATUS: USB resume\n");
+		if (dev->suspended_from == USB_STATE_POWERED)
+			gr_set_ep0state(dev, GR_EP0_DISCONNECT);
+		else
+			gr_set_ep0state(dev, GR_EP0_SETUP);
+		usb_gadget_set_state(&dev->gadget, dev->suspended_from);
+
+		if ((dev->gadget.speed != USB_SPEED_UNKNOWN) &&
+		    dev->driver && dev->driver->resume) {
+			spin_unlock(&dev->lock);
+
+			dev->driver->resume(&dev->gadget);
+
+			spin_lock(&dev->lock);
+		}
+		handled = 1;
+	}
+
+	return handled;
+}
+
+/* Non-interrupt context irq handler */
+static irqreturn_t gr_irq_handler(int irq, void *_dev)
+{
+	struct gr_udc *dev = _dev;
+	struct gr_ep *ep;
+	int handled = 0;
+	int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (!dev->irq_enabled)
+		goto out;
+
+	/*
+	 * Check IN ep interrupts. We check these before the OUT eps because
+	 * some gadgets reuse the request that might already be currently
+	 * outstanding and needs to be completed (mainly setup requests).
+	 */
+	for (i = 0; i < dev->nepi; i++) {
+		ep = &dev->epi[i];
+		if (!ep->stopped && !ep->callback && !list_empty(&ep->queue))
+			handled = gr_handle_in_ep(ep) || handled;
+	}
+
+	/* Check OUT ep interrupts */
+	for (i = 0; i < dev->nepo; i++) {
+		ep = &dev->epo[i];
+		if (!ep->stopped && !ep->callback && !list_empty(&ep->queue))
+			handled = gr_handle_out_ep(ep) || handled;
+	}
+
+	/* Check status interrupts */
+	handled = gr_handle_state_changes(dev) || handled;
+
+	/*
+	 * Check AMBA DMA errors. Only check if we didn't find anything else to
+	 * handle because this shouldn't happen if we did everything right.
+	 */
+	if (!handled) {
+		list_for_each_entry(ep, &dev->ep_list, ep_list) {
+			if (gr_read32(&ep->regs->dmactrl) & GR_DMACTRL_AE) {
+				dev_err(dev->dev,
+					"AMBA Error occurred for %s\n",
+					ep->ep.name);
+				handled = 1;
+			}
+		}
+	}
+
+out:
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+/* Interrupt context irq handler */
+static irqreturn_t gr_irq(int irq, void *_dev)
+{
+	struct gr_udc *dev = _dev;
+
+	if (!dev->irq_enabled)
+		return IRQ_NONE;
+
+	return IRQ_WAKE_THREAD;
+}
+
+/* ---------------------------------------------------------------------- */
+/* USB ep ops */
+
+/* Enable endpoint. Not for ep0in and ep0out that are handled separately. */
+static int gr_ep_enable(struct usb_ep *_ep,
+			const struct usb_endpoint_descriptor *desc)
+{
+	struct gr_udc *dev;
+	struct gr_ep *ep;
+	u8 mode;
+	u8 nt;
+	u16 max;
+	u16 buffer_size = 0;
+	u32 epctrl;
+
+	ep = container_of(_ep, struct gr_ep, ep);
+	if (!_ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT)
+		return -EINVAL;
+
+	dev = ep->dev;
+
+	/* 'ep0' IN and OUT are reserved */
+	if (ep == &dev->epo[0] || ep == &dev->epi[0])
+		return -EINVAL;
+
+	if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)
+		return -ESHUTDOWN;
+
+	/* Make sure we are clear for enabling */
+	epctrl = gr_read32(&ep->regs->epctrl);
+	if (epctrl & GR_EPCTRL_EV)
+		return -EBUSY;
+
+	/* Check that directions match */
+	if (!ep->is_in != !usb_endpoint_dir_in(desc))
+		return -EINVAL;
+
+	/* Check ep num */
+	if ((!ep->is_in && ep->num >= dev->nepo) ||
+	    (ep->is_in && ep->num >= dev->nepi))
+		return -EINVAL;
+
+	if (usb_endpoint_xfer_control(desc)) {
+		mode = 0;
+	} else if (usb_endpoint_xfer_isoc(desc)) {
+		mode = 1;
+	} else if (usb_endpoint_xfer_bulk(desc)) {
+		mode = 2;
+	} else if (usb_endpoint_xfer_int(desc)) {
+		mode = 3;
+	} else {
+		dev_err(dev->dev, "Unknown transfer type for %s\n",
+			ep->ep.name);
+		return -EINVAL;
+	}
+
+	/*
+	 * Bits 10-0 set the max payload. 12-11 set the number of
+	 * additional transactions.
+	 */
+	max = 0x7ff & usb_endpoint_maxp(desc);
+	nt = 0x3 & (usb_endpoint_maxp(desc) >> 11);
+	buffer_size = GR_BUFFER_SIZE(epctrl);
+	if (nt && (mode == 0 || mode == 2)) {
+		dev_err(dev->dev,
+			"%s mode: multiple trans./microframe not valid\n",
+			(mode == 2 ? "Bulk" : "Control"));
+		return -EINVAL;
+	} else if (nt == 0x11) {
+		dev_err(dev->dev, "Invalid value for trans./microframe\n");
+		return -EINVAL;
+	} else if ((nt + 1) * max > buffer_size) {
+		dev_err(dev->dev, "Hw buffer size %d < max payload %d * %d\n",
+			buffer_size, (nt + 1), max);
+		return -EINVAL;
+	} else if (max == 0) {
+		dev_err(dev->dev, "Max payload cannot be set to 0\n");
+		return -EINVAL;
+	}
+
+	spin_lock(&ep->dev->lock);
+
+	if (!ep->stopped) {
+		spin_unlock(&ep->dev->lock);
+		return -EBUSY;
+	}
+
+	ep->stopped = 0;
+	ep->wedged = 0;
+	ep->ep.desc = desc;
+	ep->ep.maxpacket = max;
+	ep->dma_start = 0;
+
+
+	if (nt) {
+		/*
+		 * Maximum possible size of all payloads in one microframe
+		 * regardless of direction when using high-bandwidth mode.
+		 */
+		ep->bytes_per_buffer = (nt + 1) * max;
+	} else if (ep->is_in) {
+		/*
+		 * The biggest multiple of maximum packet size that fits into
+		 * the buffer. The hardware will split up into many packets in
+		 * the IN direction.
+		 */
+		ep->bytes_per_buffer = (buffer_size / max) * max;
+	} else {
+		/*
+		 * Only single packets will be placed the buffers in the OUT
+		 * direction.
+		 */
+		ep->bytes_per_buffer = max;
+	}
+
+	epctrl = (max << GR_EPCTRL_MAXPL_POS)
+		| (nt << GR_EPCTRL_NT_POS)
+		| (mode << GR_EPCTRL_TT_POS)
+		| GR_EPCTRL_EV;
+	if (ep->is_in)
+		epctrl |= GR_EPCTRL_PI;
+	gr_write32(&ep->regs->epctrl, epctrl);
+
+	gr_write32(&ep->regs->dmactrl, GR_DMACTRL_IE | GR_DMACTRL_AI);
+
+	spin_unlock(&ep->dev->lock);
+
+	dev_dbg(ep->dev->dev, "EP: %s enabled - %s with %d bytes/buffer\n",
+		ep->ep.name, gr_modestring[mode], ep->bytes_per_buffer);
+	return 0;
+}
+
+/* Disable endpoint. Not for ep0in and ep0out that are handled separately. */
+static int gr_ep_disable(struct usb_ep *_ep)
+{
+	struct gr_ep *ep;
+	struct gr_udc *dev;
+	unsigned long flags;
+
+	ep = container_of(_ep, struct gr_ep, ep);
+	if (!_ep || !ep->ep.desc)
+		return -ENODEV;
+
+	dev = ep->dev;
+
+	/* 'ep0' IN and OUT are reserved */
+	if (ep == &dev->epo[0] || ep == &dev->epi[0])
+		return -EINVAL;
+
+	if (dev->ep0state == GR_EP0_SUSPEND)
+		return -EBUSY;
+
+	dev_dbg(ep->dev->dev, "EP: disable %s\n", ep->ep.name);
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	gr_ep_nuke(ep);
+	gr_ep_reset(ep);
+	ep->ep.desc = NULL;
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	return 0;
+}
+
+/*
+ * Frees a request, but not any DMA buffers associated with it
+ * (gr_finish_request should already have taken care of that).
+ */
+static void gr_free_request(struct usb_ep *_ep, struct usb_request *_req)
+{
+	struct gr_request *req;
+
+	if (!_ep || !_req)
+		return;
+	req = container_of(_req, struct gr_request, req);
+
+	/* Leads to memory leak */
+	WARN(!list_empty(&req->queue),
+	     "request not dequeued properly before freeing\n");
+
+	kfree(req);
+}
+
+/* Queue a request from the gadget */
+static int gr_queue_ext(struct usb_ep *_ep, struct usb_request *_req,
+			gfp_t gfp_flags)
+{
+	struct gr_ep *ep;
+	struct gr_request *req;
+	struct gr_udc *dev;
+	int ret;
+
+	if (unlikely(!_ep || !_req))
+		return -EINVAL;
+
+	ep = container_of(_ep, struct gr_ep, ep);
+	req = container_of(_req, struct gr_request, req);
+	dev = ep->dev;
+
+	spin_lock(&ep->dev->lock);
+
+	/*
+	 * The ep0 pointer in the gadget struct is used both for ep0in and
+	 * ep0out. In a data stage in the out direction ep0out needs to be used
+	 * instead of the default ep0in. Completion functions might use
+	 * driver_data, so that needs to be copied as well.
+	 */
+	if ((ep == &dev->epi[0]) && (dev->ep0state == GR_EP0_ODATA)) {
+		ep = &dev->epo[0];
+		ep->ep.driver_data = dev->epi[0].ep.driver_data;
+	}
+
+	if (ep->is_in)
+		gr_dbgprint_request("EXTERN", ep, req);
+
+	ret = gr_queue(ep, req, gfp_flags);
+
+	spin_unlock(&ep->dev->lock);
+
+	return ret;
+}
+
+/* Dequeue JUST ONE request */
+static int gr_dequeue(struct usb_ep *_ep, struct usb_request *_req)
+{
+	struct gr_request *req;
+	struct gr_ep *ep;
+	struct gr_udc *dev;
+	int ret = 0;
+	unsigned long flags;
+
+	ep = container_of(_ep, struct gr_ep, ep);
+	if (!_ep || !_req || (!ep->ep.desc && ep->num != 0))
+		return -EINVAL;
+	dev = ep->dev;
+	if (!dev->driver)
+		return -ESHUTDOWN;
+
+	/* We can't touch (DMA) registers when suspended */
+	if (dev->ep0state == GR_EP0_SUSPEND)
+		return -EBUSY;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	/* Make sure it's actually queued on this endpoint */
+	list_for_each_entry(req, &ep->queue, queue) {
+		if (&req->req == _req)
+			break;
+	}
+	if (&req->req != _req) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (list_first_entry(&ep->queue, struct gr_request, queue) == req) {
+		/* This request is currently being processed */
+		gr_abort_dma(ep);
+		if (ep->stopped)
+			gr_finish_request(ep, req, -ECONNRESET);
+		else
+			gr_dma_advance(ep, -ECONNRESET);
+	} else if (!list_empty(&req->queue)) {
+		/* Not being processed - gr_finish_request dequeues it */
+		gr_finish_request(ep, req, -ECONNRESET);
+	} else {
+		ret = -EOPNOTSUPP;
+	}
+
+out:
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	return ret;
+}
+
+/* Helper for gr_set_halt and gr_set_wedge */
+static int gr_set_halt_wedge(struct usb_ep *_ep, int halt, int wedge)
+{
+	int ret;
+	struct gr_ep *ep;
+
+	if (!_ep)
+		return -ENODEV;
+	ep = container_of(_ep, struct gr_ep, ep);
+
+	spin_lock(&ep->dev->lock);
+
+	/* Halting an IN endpoint should fail if queue is not empty */
+	if (halt && ep->is_in && !list_empty(&ep->queue)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	ret = gr_ep_halt_wedge(ep, halt, wedge, 0);
+
+out:
+	spin_unlock(&ep->dev->lock);
+
+	return ret;
+}
+
+/* Halt endpoint */
+static int gr_set_halt(struct usb_ep *_ep, int halt)
+{
+	return gr_set_halt_wedge(_ep, halt, 0);
+}
+
+/* Halt and wedge endpoint */
+static int gr_set_wedge(struct usb_ep *_ep)
+{
+	return gr_set_halt_wedge(_ep, 1, 1);
+}
+
+/*
+ * Return the total number of bytes currently stored in the internal buffers of
+ * the endpoint.
+ */
+static int gr_fifo_status(struct usb_ep *_ep)
+{
+	struct gr_ep *ep;
+	u32 epstat;
+	u32 bytes = 0;
+
+	if (!_ep)
+		return -ENODEV;
+	ep = container_of(_ep, struct gr_ep, ep);
+
+	epstat = gr_read32(&ep->regs->epstat);
+
+	if (epstat & GR_EPSTAT_B0)
+		bytes += (epstat & GR_EPSTAT_B0CNT_MASK) >> GR_EPSTAT_B0CNT_POS;
+	if (epstat & GR_EPSTAT_B1)
+		bytes += (epstat & GR_EPSTAT_B1CNT_MASK) >> GR_EPSTAT_B1CNT_POS;
+
+	return bytes;
+}
+
+
+/* Empty data from internal buffers of an endpoint. */
+static void gr_fifo_flush(struct usb_ep *_ep)
+{
+	struct gr_ep *ep;
+	u32 epctrl;
+
+	if (!_ep)
+		return;
+	ep = container_of(_ep, struct gr_ep, ep);
+	dev_vdbg(ep->dev->dev, "EP: flush fifo %s\n", ep->ep.name);
+
+	spin_lock(&ep->dev->lock);
+
+	epctrl = gr_read32(&ep->regs->epctrl);
+	epctrl |= GR_EPCTRL_CB;
+	gr_write32(&ep->regs->epctrl, epctrl);
+
+	spin_unlock(&ep->dev->lock);
+}
+
+static struct usb_ep_ops gr_ep_ops = {
+	.enable		= gr_ep_enable,
+	.disable	= gr_ep_disable,
+
+	.alloc_request	= gr_alloc_request,
+	.free_request	= gr_free_request,
+
+	.queue		= gr_queue_ext,
+	.dequeue	= gr_dequeue,
+
+	.set_halt	= gr_set_halt,
+	.set_wedge	= gr_set_wedge,
+	.fifo_status	= gr_fifo_status,
+	.fifo_flush	= gr_fifo_flush,
+};
+
+/* ---------------------------------------------------------------------- */
+/* USB Gadget ops */
+
+static int gr_get_frame(struct usb_gadget *_gadget)
+{
+	struct gr_udc *dev;
+
+	if (!_gadget)
+		return -ENODEV;
+	dev = container_of(_gadget, struct gr_udc, gadget);
+	return gr_read32(&dev->regs->status) & GR_STATUS_FN_MASK;
+}
+
+static int gr_wakeup(struct usb_gadget *_gadget)
+{
+	struct gr_udc *dev;
+
+	if (!_gadget)
+		return -ENODEV;
+	dev = container_of(_gadget, struct gr_udc, gadget);
+
+	/* Remote wakeup feature not enabled by host*/
+	if (!dev->remote_wakeup)
+		return -EINVAL;
+
+	spin_lock(&dev->lock);
+
+	gr_write32(&dev->regs->control,
+		   gr_read32(&dev->regs->control) | GR_CONTROL_RW);
+
+	spin_unlock(&dev->lock);
+
+	return 0;
+}
+
+static int gr_pullup(struct usb_gadget *_gadget, int is_on)
+{
+	struct gr_udc *dev;
+	u32 control;
+
+	if (!_gadget)
+		return -ENODEV;
+	dev = container_of(_gadget, struct gr_udc, gadget);
+
+	spin_lock(&dev->lock);
+
+	control = gr_read32(&dev->regs->control);
+	if (is_on)
+		control |= GR_CONTROL_EP;
+	else
+		control &= ~GR_CONTROL_EP;
+	gr_write32(&dev->regs->control, control);
+
+	spin_unlock(&dev->lock);
+
+	return 0;
+}
+
+static int gr_udc_start(struct usb_gadget *gadget,
+			struct usb_gadget_driver *driver)
+{
+	struct gr_udc *dev = to_gr_udc(gadget);
+
+	spin_lock(&dev->lock);
+
+	/* Hook up the driver */
+	driver->driver.bus = NULL;
+	dev->driver = driver;
+
+	/* Get ready for host detection */
+	gr_enable_vbus_detect(dev);
+
+	spin_unlock(&dev->lock);
+
+	dev_info(dev->dev, "Started with gadget driver '%s'\n",
+		 driver->driver.name);
+
+	return 0;
+}
+
+static int gr_udc_stop(struct usb_gadget *gadget,
+		       struct usb_gadget_driver *driver)
+{
+	struct gr_udc *dev = to_gr_udc(gadget);
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	dev->driver = NULL;
+	gr_stop_activity(dev);
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+
+	dev_info(dev->dev, "Stopped\n");
+
+	return 0;
+}
+
+static const struct usb_gadget_ops gr_ops = {
+	.get_frame	= gr_get_frame,
+	.wakeup         = gr_wakeup,
+	.pullup         = gr_pullup,
+	.udc_start	= gr_udc_start,
+	.udc_stop	= gr_udc_stop,
+	/* Other operations not supported */
+};
+
+/* ---------------------------------------------------------------------- */
+/* Module probe, removal and of-matching */
+
+static const char * const onames[] = {
+	"ep0out", "ep1out", "ep2out", "ep3out", "ep4out", "ep5out",
+	"ep6out", "ep7out", "ep8out", "ep9out", "ep10out", "ep11out",
+	"ep12out", "ep13out", "ep14out", "ep15out"
+};
+
+static const char * const inames[] = {
+	"ep0in", "ep1in", "ep2in", "ep3in", "ep4in", "ep5in",
+	"ep6in", "ep7in", "ep8in", "ep9in", "ep10in", "ep11in",
+	"ep12in", "ep13in", "ep14in", "ep15in"
+};
+
+/* Must be called with dev->lock held */
+static int gr_ep_init(struct gr_udc *dev, int num, int is_in, u32 maxplimit)
+{
+	struct gr_ep *ep;
+	struct gr_request *req;
+	struct usb_request *_req;
+	void *buf;
+
+	if (is_in) {
+		ep = &dev->epi[num];
+		ep->ep.name = inames[num];
+		ep->regs = &dev->regs->epi[num];
+	} else {
+		ep = &dev->epo[num];
+		ep->ep.name = onames[num];
+		ep->regs = &dev->regs->epo[num];
+	}
+
+	gr_ep_reset(ep);
+	ep->num = num;
+	ep->is_in = is_in;
+	ep->dev = dev;
+	ep->ep.ops = &gr_ep_ops;
+	INIT_LIST_HEAD(&ep->queue);
+
+	if (num == 0) {
+		_req = gr_alloc_request(&ep->ep, GFP_KERNEL);
+		buf = devm_kzalloc(dev->dev, PAGE_SIZE, GFP_DMA | GFP_KERNEL);
+		if (!_req || !buf) {
+			/* possible _req freed by gr_probe via gr_remove */
+			return -ENOMEM;
+		}
+
+		req = container_of(_req, struct gr_request, req);
+		req->req.buf = buf;
+		req->req.length = MAX_CTRL_PL_SIZE;
+
+		if (is_in)
+			dev->ep0reqi = req; /* Complete gets set as used */
+		else
+			dev->ep0reqo = req; /* Completion treated separately */
+
+		usb_ep_set_maxpacket_limit(&ep->ep, MAX_CTRL_PL_SIZE);
+		ep->bytes_per_buffer = MAX_CTRL_PL_SIZE;
+	} else {
+		usb_ep_set_maxpacket_limit(&ep->ep, (u16)maxplimit);
+		list_add_tail(&ep->ep.ep_list, &dev->gadget.ep_list);
+	}
+	list_add_tail(&ep->ep_list, &dev->ep_list);
+
+	return 0;
+}
+
+/* Must be called with dev->lock held */
+static int gr_udc_init(struct gr_udc *dev)
+{
+	struct device_node *np = dev->dev->of_node;
+	u32 epctrl_val;
+	u32 dmactrl_val;
+	int i;
+	int ret = 0;
+	u32 *bufsizes;
+	u32 bufsize;
+	int len;
+
+	gr_set_address(dev, 0);
+
+	INIT_LIST_HEAD(&dev->gadget.ep_list);
+	dev->gadget.speed = USB_SPEED_UNKNOWN;
+	dev->gadget.ep0 = &dev->epi[0].ep;
+
+	INIT_LIST_HEAD(&dev->ep_list);
+	gr_set_ep0state(dev, GR_EP0_DISCONNECT);
+
+	bufsizes = (u32 *)of_get_property(np, "epobufsizes", &len);
+	len /= sizeof(u32);
+	for (i = 0; i < dev->nepo; i++) {
+		bufsize = (bufsizes && i < len) ? bufsizes[i] : 1024;
+		ret = gr_ep_init(dev, i, 0, bufsize);
+		if (ret)
+			return ret;
+	}
+
+	bufsizes = (u32 *)of_get_property(np, "epibufsizes", &len);
+	len /= sizeof(u32);
+	for (i = 0; i < dev->nepi; i++) {
+		bufsize = (bufsizes && i < len) ? bufsizes[i] : 1024;
+		ret = gr_ep_init(dev, i, 1, bufsize);
+		if (ret)
+			return ret;
+	}
+
+	/* Must be disabled by default */
+	dev->remote_wakeup = 0;
+
+	/* Enable ep0out and ep0in */
+	epctrl_val = (MAX_CTRL_PL_SIZE << GR_EPCTRL_MAXPL_POS) | GR_EPCTRL_EV;
+	dmactrl_val = GR_DMACTRL_IE | GR_DMACTRL_AI;
+	gr_write32(&dev->epo[0].regs->epctrl, epctrl_val);
+	gr_write32(&dev->epi[0].regs->epctrl, epctrl_val | GR_EPCTRL_PI);
+	gr_write32(&dev->epo[0].regs->dmactrl, dmactrl_val);
+	gr_write32(&dev->epi[0].regs->dmactrl, dmactrl_val);
+
+	return 0;
+}
+
+static int gr_remove(struct platform_device *ofdev)
+{
+	struct gr_udc *dev = dev_get_drvdata(&ofdev->dev);
+
+	if (dev->added)
+		usb_del_gadget_udc(&dev->gadget); /* Shuts everything down */
+	if (dev->driver)
+		return -EBUSY;
+
+	gr_dfs_delete(dev);
+	if (dev->desc_pool)
+		dma_pool_destroy(dev->desc_pool);
+	dev_set_drvdata(&ofdev->dev, NULL);
+
+	gr_free_request(&dev->epi[0].ep, &dev->ep0reqi->req);
+	gr_free_request(&dev->epo[0].ep, &dev->ep0reqo->req);
+
+	return 0;
+}
+static int gr_request_irq(struct gr_udc *dev, int irq)
+{
+	return devm_request_threaded_irq(dev->dev, irq, gr_irq, gr_irq_handler,
+					 IRQF_SHARED, driver_name, dev);
+}
+
+static int gr_probe(struct platform_device *ofdev)
+{
+	struct gr_udc *dev;
+	struct resource *res;
+	struct gr_regs __iomem *regs;
+	int retval;
+	u32 status;
+
+	dev = devm_kzalloc(&ofdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+	dev->dev = &ofdev->dev;
+
+	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(dev->dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	dev->irq = irq_of_parse_and_map(dev->dev->of_node, 0);
+	if (!dev->irq) {
+		dev_err(dev->dev, "No irq found\n");
+		return -ENODEV;
+	}
+
+	/* Some core configurations has separate irqs for IN and OUT events */
+	dev->irqi = irq_of_parse_and_map(dev->dev->of_node, 1);
+	if (dev->irqi) {
+		dev->irqo = irq_of_parse_and_map(dev->dev->of_node, 2);
+		if (!dev->irqo) {
+			dev_err(dev->dev, "Found irqi but not irqo\n");
+			return -ENODEV;
+		}
+	}
+
+	dev->gadget.name = driver_name;
+	dev->gadget.max_speed = USB_SPEED_HIGH;
+	dev->gadget.ops = &gr_ops;
+	dev->gadget.quirk_ep_out_aligned_size = true;
+
+	spin_lock_init(&dev->lock);
+	dev->regs = regs;
+
+	dev_set_drvdata(&ofdev->dev, dev);
+
+	/* Determine number of endpoints and data interface mode */
+	status = gr_read32(&dev->regs->status);
+	dev->nepi = ((status & GR_STATUS_NEPI_MASK) >> GR_STATUS_NEPI_POS) + 1;
+	dev->nepo = ((status & GR_STATUS_NEPO_MASK) >> GR_STATUS_NEPO_POS) + 1;
+
+	if (!(status & GR_STATUS_DM)) {
+		dev_err(dev->dev, "Slave mode cores are not supported\n");
+		return -ENODEV;
+	}
+
+	/* --- Effects of the following calls might need explicit cleanup --- */
+
+	/* Create DMA pool for descriptors */
+	dev->desc_pool = dma_pool_create("desc_pool", dev->dev,
+					 sizeof(struct gr_dma_desc), 4, 0);
+	if (!dev->desc_pool) {
+		dev_err(dev->dev, "Could not allocate DMA pool");
+		return -ENOMEM;
+	}
+
+	spin_lock(&dev->lock);
+
+	/* Inside lock so that no gadget can use this udc until probe is done */
+	retval = usb_add_gadget_udc(dev->dev, &dev->gadget);
+	if (retval) {
+		dev_err(dev->dev, "Could not add gadget udc");
+		goto out;
+	}
+	dev->added = 1;
+
+	retval = gr_udc_init(dev);
+	if (retval)
+		goto out;
+
+	gr_dfs_create(dev);
+
+	/* Clear all interrupt enables that might be left on since last boot */
+	gr_disable_interrupts_and_pullup(dev);
+
+	retval = gr_request_irq(dev, dev->irq);
+	if (retval) {
+		dev_err(dev->dev, "Failed to request irq %d\n", dev->irq);
+		goto out;
+	}
+
+	if (dev->irqi) {
+		retval = gr_request_irq(dev, dev->irqi);
+		if (retval) {
+			dev_err(dev->dev, "Failed to request irqi %d\n",
+				dev->irqi);
+			goto out;
+		}
+		retval = gr_request_irq(dev, dev->irqo);
+		if (retval) {
+			dev_err(dev->dev, "Failed to request irqo %d\n",
+				dev->irqo);
+			goto out;
+		}
+	}
+
+	if (dev->irqi)
+		dev_info(dev->dev, "regs: %p, irqs %d, %d, %d\n", dev->regs,
+			 dev->irq, dev->irqi, dev->irqo);
+	else
+		dev_info(dev->dev, "regs: %p, irq %d\n", dev->regs, dev->irq);
+
+out:
+	spin_unlock(&dev->lock);
+
+	if (retval)
+		gr_remove(ofdev);
+
+	return retval;
+}
+
+static struct of_device_id gr_match[] = {
+	{.name = "GAISLER_USBDC"},
+	{.name = "01_021"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, gr_match);
+
+static struct platform_driver gr_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = gr_match,
+	},
+	.probe = gr_probe,
+	.remove = gr_remove,
+};
+module_platform_driver(gr_driver);
+
+MODULE_AUTHOR("Aeroflex Gaisler AB.");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
diff --git a/drivers/usb/gadget/gr_udc.h b/drivers/usb/gadget/gr_udc.h
new file mode 100644
index 0000000..8388897
--- /dev/null
+++ b/drivers/usb/gadget/gr_udc.h
@@ -0,0 +1,220 @@
+/*
+ * USB Peripheral Controller driver for Aeroflex Gaisler GRUSBDC.
+ *
+ * 2013 (c) Aeroflex Gaisler AB
+ *
+ * This driver supports GRUSBDC USB Device Controller cores available in the
+ * GRLIB VHDL IP core library.
+ *
+ * Full documentation of the GRUSBDC core can be found here:
+ * http://www.gaisler.com/products/grlib/grip.pdf
+ *
+ * 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.
+ *
+ * Contributors:
+ * - Andreas Larsson <andreas@gaisler.com>
+ * - Marko Isomaki
+ */
+
+/* Control registers on the AMBA bus */
+
+#define GR_MAXEP	16	/* Max # endpoints for *each* direction */
+
+struct gr_epregs {
+	u32 epctrl;
+	union {
+		struct { /* Slave mode*/
+			u32 slvctrl;
+			u32 slvdata;
+		};
+		struct { /* DMA mode*/
+			u32 dmactrl;
+			u32 dmaaddr;
+		};
+	};
+	u32 epstat;
+};
+
+struct gr_regs {
+	struct gr_epregs	epo[GR_MAXEP];	/* 0x000 - 0x0fc */
+	struct gr_epregs	epi[GR_MAXEP];	/* 0x100 - 0x1fc */
+	u32			control;	/* 0x200 */
+	u32			status;		/* 0x204 */
+};
+
+#define GR_EPCTRL_BUFSZ_SCALER	8
+#define GR_EPCTRL_BUFSZ_MASK	0xffe00000
+#define GR_EPCTRL_BUFSZ_POS	21
+#define GR_EPCTRL_PI		BIT(20)
+#define GR_EPCTRL_CB		BIT(19)
+#define GR_EPCTRL_CS		BIT(18)
+#define GR_EPCTRL_MAXPL_MASK	0x0003ff80
+#define GR_EPCTRL_MAXPL_POS	7
+#define GR_EPCTRL_NT_MASK	0x00000060
+#define GR_EPCTRL_NT_POS	5
+#define GR_EPCTRL_TT_MASK	0x00000018
+#define GR_EPCTRL_TT_POS	3
+#define GR_EPCTRL_EH		BIT(2)
+#define GR_EPCTRL_ED		BIT(1)
+#define GR_EPCTRL_EV		BIT(0)
+
+#define GR_DMACTRL_AE		BIT(10)
+#define GR_DMACTRL_AD		BIT(3)
+#define GR_DMACTRL_AI		BIT(2)
+#define GR_DMACTRL_IE		BIT(1)
+#define GR_DMACTRL_DA		BIT(0)
+
+#define GR_EPSTAT_PT		BIT(29)
+#define GR_EPSTAT_PR		BIT(29)
+#define GR_EPSTAT_B1CNT_MASK	0x1fff0000
+#define GR_EPSTAT_B1CNT_POS	16
+#define GR_EPSTAT_B0CNT_MASK	0x0000fff8
+#define GR_EPSTAT_B0CNT_POS	3
+#define GR_EPSTAT_B1		BIT(2)
+#define GR_EPSTAT_B0		BIT(1)
+#define GR_EPSTAT_BS		BIT(0)
+
+#define GR_CONTROL_SI		BIT(31)
+#define GR_CONTROL_UI		BIT(30)
+#define GR_CONTROL_VI		BIT(29)
+#define GR_CONTROL_SP		BIT(28)
+#define GR_CONTROL_FI		BIT(27)
+#define GR_CONTROL_EP		BIT(14)
+#define GR_CONTROL_DH		BIT(13)
+#define GR_CONTROL_RW		BIT(12)
+#define GR_CONTROL_TS_MASK	0x00000e00
+#define GR_CONTROL_TS_POS	9
+#define GR_CONTROL_TM		BIT(8)
+#define GR_CONTROL_UA_MASK	0x000000fe
+#define GR_CONTROL_UA_POS	1
+#define GR_CONTROL_SU		BIT(0)
+
+#define GR_STATUS_NEPI_MASK	0xf0000000
+#define GR_STATUS_NEPI_POS	28
+#define GR_STATUS_NEPO_MASK	0x0f000000
+#define GR_STATUS_NEPO_POS	24
+#define GR_STATUS_DM		BIT(23)
+#define GR_STATUS_SU		BIT(17)
+#define GR_STATUS_UR		BIT(16)
+#define GR_STATUS_VB		BIT(15)
+#define GR_STATUS_SP		BIT(14)
+#define GR_STATUS_AF_MASK	0x00003800
+#define GR_STATUS_AF_POS	11
+#define GR_STATUS_FN_MASK	0x000007ff
+#define GR_STATUS_FN_POS	0
+
+
+#define MAX_CTRL_PL_SIZE 64 /* As per USB standard for full and high speed */
+
+/*-------------------------------------------------------------------------*/
+
+/* Driver data structures and utilities */
+
+struct gr_dma_desc {
+	u32 ctrl;
+	u32 data;
+	u32 next;
+
+	/* These must be last because hw uses the previous three */
+	u32 paddr;
+	struct gr_dma_desc *next_desc;
+};
+
+#define GR_DESC_OUT_CTRL_SE		BIT(17)
+#define GR_DESC_OUT_CTRL_IE		BIT(15)
+#define GR_DESC_OUT_CTRL_NX		BIT(14)
+#define GR_DESC_OUT_CTRL_EN		BIT(13)
+#define GR_DESC_OUT_CTRL_LEN_MASK	0x00001fff
+
+#define GR_DESC_IN_CTRL_MO		BIT(18)
+#define GR_DESC_IN_CTRL_PI		BIT(17)
+#define GR_DESC_IN_CTRL_ML		BIT(16)
+#define GR_DESC_IN_CTRL_IE		BIT(15)
+#define GR_DESC_IN_CTRL_NX		BIT(14)
+#define GR_DESC_IN_CTRL_EN		BIT(13)
+#define GR_DESC_IN_CTRL_LEN_MASK	0x00001fff
+
+#define GR_DESC_DMAADDR_MASK		0xfffffffc
+
+struct gr_ep {
+	struct usb_ep ep;
+	struct gr_udc *dev;
+	u16 bytes_per_buffer;
+	unsigned int dma_start;
+	struct gr_epregs __iomem *regs;
+
+	unsigned num:8;
+	unsigned is_in:1;
+	unsigned stopped:1;
+	unsigned wedged:1;
+	unsigned callback:1;
+
+	/* analogous to a host-side qh */
+	struct list_head queue;
+
+	struct list_head ep_list;
+};
+
+struct gr_request {
+	struct usb_request req;
+	struct list_head queue;
+
+	/* Chain of dma descriptors */
+	struct gr_dma_desc *first_desc; /* First in the chain */
+	struct gr_dma_desc *curr_desc; /* Current descriptor */
+	struct gr_dma_desc *last_desc; /* Last in the chain */
+
+	u8 setup; /* Setup packet */
+};
+
+enum gr_ep0state {
+	GR_EP0_DISCONNECT = 0,	/* No host */
+	GR_EP0_SETUP,		/* Between STATUS ack and SETUP report */
+	GR_EP0_IDATA,		/* IN data stage */
+	GR_EP0_ODATA,		/* OUT data stage */
+	GR_EP0_ISTATUS,		/* Status stage after IN data stage */
+	GR_EP0_OSTATUS,		/* Status stage after OUT data stage */
+	GR_EP0_STALL,		/* Data or status stages */
+	GR_EP0_SUSPEND,		/* USB suspend */
+};
+
+struct gr_udc {
+	struct usb_gadget gadget;
+	struct gr_ep epi[GR_MAXEP];
+	struct gr_ep epo[GR_MAXEP];
+	struct usb_gadget_driver *driver;
+	struct dma_pool *desc_pool;
+	struct device *dev;
+
+	enum gr_ep0state ep0state;
+	struct gr_request *ep0reqo;
+	struct gr_request *ep0reqi;
+
+	struct gr_regs __iomem *regs;
+	int irq;
+	int irqi;
+	int irqo;
+
+	unsigned added:1;
+	unsigned irq_enabled:1;
+	unsigned remote_wakeup:1;
+
+	u8 test_mode;
+
+	enum usb_device_state suspended_from;
+
+	unsigned int nepi;
+	unsigned int nepo;
+
+	struct list_head ep_list;
+
+	spinlock_t lock; /* General lock, a.k.a. "dev->lock" in comments */
+
+	struct dentry *dfs_root;
+	struct dentry *dfs_state;
+};
+
+#define to_gr_udc(gadget)	(container_of((gadget), struct gr_udc, gadget))