[PATCH v3 2/2] usb: gadget: Add xilinx axi usb2 device support

[subbaraya.sundeep.bhatta]

From: Subbaraya Sundeep Bhatta <sbhatta@xxxxxxxxxx>

This patch adds xilinx axi usb2 device driver support

Signed-off-by: Subbaraya Sundeep Bhatta <sbhatta@xxxxxxxxxx>
---
Changes for v3:
	- Added pullup function
	- Modified error handling 
	- Fixed all v2 comments	except DMA interrupt handling
	  since polling seems to be faster. 
Please refer to below message thread:
	http://www.kernelhub.org/?p=2&msg=481724

Changes for v2:
	- Added Resume
	- Added Remote wakeup
	- Fixed v1 comments

 drivers/usb/gadget/Kconfig      |   14 +
 drivers/usb/gadget/Makefile     |    1 +
 drivers/usb/gadget/udc-xilinx.c | 2273 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 2288 insertions(+), 0 deletions(-)
 create mode 100644 drivers/usb/gadget/udc-xilinx.c

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index ba18e9c..83560dc 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -459,6 +459,20 @@ config USB_EG20T
 	  ML7213/ML7831 is companion chip for Intel Atom E6xx series.
 	  ML7213/ML7831 is completely compatible for Intel EG20T PCH.
 
+config USB_GADGET_XILINX
+	tristate "Xilinx USB Driver"
+	depends on COMPILE_TEST
+	help
+	  USB peripheral controller driver for Xilinx AXI USB2 device.
+	  Xilinx AXI USB2 device is a soft IP which supports both full
+	  and high speed USB 2.0 data transfers. It has seven configurable
+	  endpoints(bulk or interrupt or isochronous), as well as
+	  endpoint zero(for control transfers).
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "xilinx_udc" and force all
+	  gadget drivers to also be dynamically linked.
+
 #
 # LAST -- dummy/emulated controller
 #
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 49514ea..dc6dd41 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
+obj-$(CONFIG_USB_GADGET_XILINX)	+= udc-xilinx.o
 
 # USB Functions
 usb_f_acm-y			:= f_acm.o
diff --git a/drivers/usb/gadget/udc-xilinx.c b/drivers/usb/gadget/udc-xilinx.c
new file mode 100644
index 0000000..f377e8a
--- /dev/null
+++ b/drivers/usb/gadget/udc-xilinx.c
@@ -0,0 +1,2273 @@
+/*
+ * Xilinx USB peripheral controller driver
+ *
+ * Copyright (C) 2004 by Thomas Rathbone
+ * Copyright (C) 2005 by HP Labs
+ * Copyright (C) 2005 by David Brownell
+ * Copyright (C) 2010 - 2014 Xilinx, Inc.
+ *
+ * Some parts of this driver code is based on the driver for at91-series
+ * USB peripheral controller (at91_udc.c).
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include "gadget_chips.h"
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/prefetch.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+
+/* Register offsets for the USB device.*/
+#define XUSB_EP0_CONFIG_OFFSET		0x0000  /* EP0 Config Reg Offset */
+#define XUSB_SETUP_PKT_ADDR_OFFSET	0x0080  /* Setup Packet Address */
+#define XUSB_ADDRESS_OFFSET		0x0100  /* Address Register */
+#define XUSB_CONTROL_OFFSET		0x0104  /* Control Register */
+#define XUSB_STATUS_OFFSET		0x0108  /* Status Register */
+#define XUSB_FRAMENUM_OFFSET		0x010C	/* Frame Number Register */
+#define XUSB_IER_OFFSET			0x0110	/* Interrupt Enable Register */
+#define XUSB_BUFFREADY_OFFSET		0x0114	/* Buffer Ready Register */
+#define XUSB_TESTMODE_OFFSET		0x0118	/* Test Mode Register */
+#define XUSB_DMA_RESET_OFFSET		0x0200  /* DMA Soft Reset Register */
+#define XUSB_DMA_CONTROL_OFFSET		0x0204	/* DMA Control Register */
+#define XUSB_DMA_DSAR_ADDR_OFFSET	0x0208	/* DMA source Address Reg */
+#define XUSB_DMA_DDAR_ADDR_OFFSET	0x020C	/* DMA destination Addr Reg */
+#define XUSB_DMA_LENGTH_OFFSET		0x0210	/* DMA Length Register */
+#define XUSB_DMA_STATUS_OFFSET		0x0214	/* DMA Status Register */
+
+/* Endpoint Configuration Space offsets */
+#define XUSB_EP_CFGSTATUS_OFFSET	0x00	/* Endpoint Config Status  */
+#define XUSB_EP_BUF0COUNT_OFFSET	0x08	/* Buffer 0 Count */
+#define XUSB_EP_BUF1COUNT_OFFSET	0x0C	/* Buffer 1 Count */
+
+#define XUSB_CONTROL_USB_READY_MASK	0x80000000 /* USB ready Mask */
+#define XUSB_CONTROL_USB_RMTWAKE_MASK	0x40000000 /* Remote wake up mask */
+
+/* Interrupt register related masks.*/
+#define XUSB_STATUS_GLOBAL_INTR_MASK	0x80000000 /* Global Intr Enable */
+#define XUSB_STATUS_DMADONE_MASK	0x04000000 /* DMA done Mask */
+#define XUSB_STATUS_DMAERR_MASK		0x02000000 /* DMA Error Mask */
+#define XUSB_STATUS_DMABUSY_MASK	0x80000000 /* DMA Error Mask */
+#define XUSB_STATUS_RESUME_MASK		0x01000000 /* USB Resume Mask */
+#define XUSB_STATUS_RESET_MASK		0x00800000 /* USB Reset Mask */
+#define XUSB_STATUS_SUSPEND_MASK	0x00400000 /* USB Suspend Mask */
+#define XUSB_STATUS_DISCONNECT_MASK	0x00200000 /* USB Disconnect Mask */
+#define XUSB_STATUS_FIFO_BUFF_RDY_MASK	0x00100000 /* FIFO Buff Ready Mask */
+#define XUSB_STATUS_FIFO_BUFF_FREE_MASK	0x00080000 /* FIFO Buff Free Mask */
+#define XUSB_STATUS_SETUP_PACKET_MASK	0x00040000 /* Setup packet received */
+#define XUSB_STATUS_EP1_BUFF2_COMP_MASK	0x00000200 /* EP 1 Buff 2 Processed */
+#define XUSB_STATUS_EP1_BUFF1_COMP_MASK	0x00000002 /* EP 1 Buff 1 Processed */
+#define XUSB_STATUS_EP0_BUFF2_COMP_MASK	0x00000100 /* EP 0 Buff 2 Processed */
+#define XUSB_STATUS_EP0_BUFF1_COMP_MASK	0x00000001 /* EP 0 Buff 1 Processed */
+#define XUSB_STATUS_HIGH_SPEED_MASK	0x00010000 /* USB Speed Mask */
+/* Suspend,Reset,Suspend and Disconnect Mask */
+#define XUSB_STATUS_INTR_EVENT_MASK	0x01E00000
+/* Buffers  completion Mask */
+#define XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK	0x0000FEFF
+/* Mask for buffer 0 and buffer 1 completion for all Endpoints */
+#define XUSB_STATUS_INTR_BUFF_COMP_SHIFT_MASK	0x00000101
+#define XUSB_STATUS_EP_BUFF2_SHIFT	8	   /* EP buffer offset */
+
+/* Endpoint Configuration Status Register */
+#define XUSB_EP_CFG_VALID_MASK		0x80000000 /* Endpoint Valid bit */
+#define XUSB_EP_CFG_STALL_MASK		0x40000000 /* Endpoint Stall bit */
+#define XUSB_EP_CFG_DATA_TOGGLE_MASK	0x08000000 /* Endpoint Data toggle */
+
+/* USB device specific global configuration constants.*/
+#define XUSB_MAX_ENDPOINTS		8	/* Maximum End Points */
+#define XUSB_EP_NUMBER_ZERO		0	/* End point Zero */
+/* DPRAM is the source address for DMA transfer */
+#define XUSB_DMA_READ_FROM_DPRAM	0x80000000
+#define XUSB_DMA_DMASR_BUSY		0x80000000 /* DMA busy */
+#define XUSB_DMA_DMASR_ERROR		0x40000000 /* DMA Error */
+/*
+ * When this bit is set, the DMA buffer ready bit is set by hardware upon
+ * DMA transfer completion.
+ */
+#define XUSB_DMA_BRR_CTRL		0x40000000 /* DMA bufready ctrl bit */
+/* Phase States */
+#define SETUP_PHASE			0x0000	/* Setup Phase */
+#define DATA_PHASE			0x0001  /* Data Phase */
+#define STATUS_PHASE			0x0002  /* Status Phase */
+
+#define EP0_MAX_PACKET		64 /* Endpoint 0 maximum packet length */
+
+/* container_of helper macros */
+#define to_udc(g)	 container_of((g), struct xusb_udc, gadget)
+#define to_xusb_ep(ep)	 container_of((ep), struct xusb_ep, ep_usb)
+#define to_xusb_req(req) container_of((req), struct xusb_req, usb_req)
+
+/**
+ * struct xusb_req - Xilinx USB device request structure
+ * @usb_req: Linux usb request structure
+ * @queue: usb device request queue
+ * @ep: pointer to xusb_endpoint structure
+ */
+struct xusb_req {
+	struct usb_request usb_req;
+	struct list_head queue;
+	struct xusb_ep *ep;
+};
+
+/**
+ * struct xusb_ep - USB end point structure.
+ * @ep_usb: usb endpoint instance
+ * @queue: endpoint message queue
+ * @udc: xilinx usb peripheral driver instance pointer
+ * @desc: pointer to the usb endpoint descriptor
+ * @rambase: the endpoint buffer address
+ * @offset: the endpoint register offset value
+ * @name: name of the endpoint
+ * @epnumber: endpoint number
+ * @maxpacket: maximum packet size the endpoint can store
+ * @buffer0count: the size of the packet recieved in the first buffer
+ * @buffer1count: the size of the packet received in the second buffer
+ * @buffer0ready: the busy state of first buffer
+ * @buffer1ready: the busy state of second buffer
+ * @eptype: endpoint transfer type (BULK, INTERRUPT)
+ * @curbufnum: current buffer of endpoint that will be processed next
+ * @is_in: endpoint direction (IN or OUT)
+ * @is_iso: endpoint type(isochronous or non isochronous)
+ */
+struct xusb_ep {
+	struct usb_ep ep_usb;
+	struct list_head queue;
+	struct xusb_udc *udc;
+	const struct usb_endpoint_descriptor *desc;
+	u32 rambase;
+	u32 offset;
+	char name[4];
+	u16 epnumber;
+	u16 maxpacket;
+	u16 buffer0count;
+	u16 buffer1count;
+	u8 buffer0ready;
+	u8 buffer1ready;
+	u8 eptype;
+	u8 curbufnum;
+	u8 is_in;
+	u8 is_iso;
+};
+
+/**
+ * struct xusb_udc -  USB peripheral driver structure
+ * @gadget: USB gadget driver instance
+ * @ep: an array of endpoint structures
+ * @driver: pointer to the usb gadget driver instance
+ * @setup: usb_ctrlrequest structure for control requests
+ * @req: pointer to dummy request for get status command
+ * @dev: pointer to device structure in gadget
+ * @usb_state: device in suspended state or not
+ * @remote_wkp: remote wakeup enabled by host
+ * @setupseqtx: tx status
+ * @setupseqrx: rx status
+ * @read_fn: function pointer to read device registers
+ * @write_fn: function pointer to write to device registers
+ * @base_address: the usb device base address
+ * @lock: instance of spinlock
+ * @dma_enabled: flag indicating whether the dma is included in the system
+ */
+struct xusb_udc {
+	struct usb_gadget gadget;
+	struct xusb_ep ep[8];
+	struct usb_gadget_driver *driver;
+	struct usb_ctrlrequest setup;
+	struct xusb_req *req;
+	struct device *dev;
+	u32 usb_state;
+	u32 remote_wkp;
+	u32 setupseqtx;
+	u32 setupseqrx;
+	unsigned int (*read_fn)(void __iomem *);
+	void (*write_fn)(void __iomem *, u32, u32);
+	void __iomem *base_address;
+	spinlock_t lock;
+	bool dma_enabled;
+};
+
+/* Endpoint buffer start addresses in the core */
+static u32 rambase[8] = { 0x22, 0x1000, 0x1100, 0x1200, 0x1300, 0x1400, 0x1500,
+			0x1600 };
+
+static const char driver_name[] = "xilinx-udc";
+static const char ep0name[] = "ep0";
+
+/* Control endpoint configuration.*/
+static const struct usb_endpoint_descriptor config_bulk_out_desc = {
+	.bLength		= USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType	= USB_DT_ENDPOINT,
+	.bEndpointAddress	= USB_DIR_OUT,
+	.bmAttributes		= USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize		= __constant_cpu_to_le16(64),
+};
+
+/**
+ * xudc_write32 - little endian write to device registers
+ * @addr: base addr of device registers
+ * @offset: register offset
+ * @val: data to be written
+ */
+static void xudc_write32(void __iomem *addr, u32 offset, u32 val)
+{
+	iowrite32(val, addr + offset);
+}
+
+/**
+ * xudc_read32 - little endian read from device registers
+ * @addr: addr of device register
+ * Return: value at addr
+ */
+static unsigned int xudc_read32(void __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+/**
+ * xudc_write32_be - big endian write to device registers
+ * @addr: base addr of device registers
+ * @offset: register offset
+ * @val: data to be written
+ */
+static void xudc_write32_be(void __iomem *addr, u32 offset, u32 val)
+{
+	iowrite32be(val, addr + offset);
+}
+
+/**
+ * xudc_read32_be - big endian read from device registers
+ * @addr: addr of device register
+ * Return: value at addr
+ */
+static unsigned int xudc_read32_be(void __iomem *addr)
+{
+	return ioread32be(addr);
+}
+
+/**
+ * xudc_wrstatus - Sets up the usb device status stages.
+ * @udc: pointer to the usb device controller structure.
+ */
+static void xudc_wrstatus(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO];
+	u32 epcfgreg;
+
+	epcfgreg = udc->read_fn(udc->base_address + ep0->offset)|
+			XUSB_EP_CFG_DATA_TOGGLE_MASK;
+	udc->write_fn(udc->base_address, ep0->offset, epcfgreg);
+	udc->write_fn(udc->base_address, ep0->offset + XUSB_EP_BUF0COUNT_OFFSET,
+			0);
+	udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET, 1);
+}
+
+/**
+ * xudc_epconfig - Configures the given endpoint.
+ * @ep: pointer to the usb device endpoint structure.
+ * @udc: pointer to the usb peripheral controller structure.
+ *
+ * This function configures a specific endpoint with the given configuration
+ * data.
+ */
+static void xudc_epconfig(struct xusb_ep *ep, struct xusb_udc *udc)
+{
+	u32 epcfgreg;
+
+	/*
+	 * Configure the end point direction, type, Max Packet Size and the
+	 * EP buffer location.
+	 */
+	epcfgreg = ((ep->is_in << 29) | (ep->eptype << 28) |
+			(ep->ep_usb.maxpacket << 15) | (ep->rambase));
+	udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+
+	/* Set the Buffer count and the Buffer ready bits.*/
+	udc->write_fn(udc->base_address, ep->offset + XUSB_EP_BUF0COUNT_OFFSET,
+			ep->buffer0count);
+	udc->write_fn(udc->base_address, ep->offset + XUSB_EP_BUF1COUNT_OFFSET,
+			ep->buffer1count);
+	if (ep->buffer0ready)
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET,
+				1 << ep->epnumber);
+	if (ep->buffer1ready)
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET, 1 <<
+				 (ep->epnumber + XUSB_STATUS_EP_BUFF2_SHIFT));
+}
+
+/**
+ * xudc_start_dma - Starts DMA transfer.
+ * @ep: pointer to the usb device endpoint structure.
+ * @src: DMA source address.
+ * @dst: DMA destination address.
+ * @length: number of bytes to transfer.
+ *
+ * Return: 0 on success, error code on failure
+ *
+ * This function starts DMA transfer by writing to DMA source,
+ * destination and lenth registers.
+ */
+static int xudc_start_dma(struct xusb_ep *ep, dma_addr_t src,
+				dma_addr_t dst, u32 length)
+{
+	struct xusb_udc *udc = ep->udc;
+	int rc = 0;
+	u32 timeout = 500;
+	u32 reg;
+
+	/*
+	 * Set the addresses in the DMA source and
+	 * destination registers and then set the length
+	 * into the DMA length register.
+	 */
+	udc->write_fn(udc->base_address, XUSB_DMA_DSAR_ADDR_OFFSET, src);
+	udc->write_fn(udc->base_address, XUSB_DMA_DDAR_ADDR_OFFSET, dst);
+	udc->write_fn(udc->base_address, XUSB_DMA_LENGTH_OFFSET, length);
+
+	/*
+	 * Wait till DMA transaction is complete and
+	 * check whether the DMA transaction was
+	 * successful.
+	 */
+	do {
+		reg = udc->read_fn(udc->base_address + XUSB_DMA_STATUS_OFFSET);
+		if (!(reg &  XUSB_DMA_DMASR_BUSY))
+			break;
+
+		/*
+		 * We can't sleep here, because it's also called from
+		 * interrupt context.
+		 */
+		timeout--;
+		if (!timeout) {
+			dev_err(udc->dev, "DMA timeout\n");
+			return -ETIMEDOUT;
+		}
+		udelay(1);
+	} while (1);
+
+	if ((udc->read_fn(udc->base_address + XUSB_DMA_STATUS_OFFSET) &
+			XUSB_DMA_DMASR_ERROR) == XUSB_DMA_DMASR_ERROR){
+		dev_err(udc->dev, "DMA Error\n");
+		rc = -EINVAL;
+	}
+
+	return rc;
+}
+
+/**
+ * xudc_dma_send - Sends IN data using DMA.
+ * @ep: pointer to the usb device endpoint structure.
+ * @req: pointer to the usb request structure.
+ * @buffer: pointer to data to be sent.
+ * @length: number of bytes to send.
+ *
+ * Return: 0 on success, -EAGAIN if no buffer is free and error
+ *	   code on failure.
+ *
+ * This function sends data using DMA.
+ */
+static int xudc_dma_send(struct xusb_ep *ep, struct xusb_req *req,
+			u8 *buffer, u32 length)
+{
+	u32 *eprambase;
+	dma_addr_t src;
+	dma_addr_t dst;
+	int ret;
+	struct xusb_udc *udc = ep->udc;
+
+	src = req->usb_req.dma + req->usb_req.actual;
+	if (req->usb_req.length)
+		dma_sync_single_for_device(udc->dev, src,
+						length, DMA_TO_DEVICE);
+	if (!ep->curbufnum && !ep->buffer0ready) {
+		/* Get the Buffer address and copy the transmit data.*/
+		eprambase = (u32 __force *)(ep->udc->base_address +
+				ep->rambase);
+		dst = virt_to_phys(eprambase);
+		udc->write_fn(udc->base_address, ep->offset +
+				XUSB_EP_BUF0COUNT_OFFSET, length);
+		udc->write_fn(udc->base_address, XUSB_DMA_CONTROL_OFFSET,
+				XUSB_DMA_BRR_CTRL | (1 << ep->epnumber));
+		ep->buffer0ready = 1;
+		ep->curbufnum = 1;
+	} else if (ep->curbufnum && !ep->buffer1ready) {
+		/* Get the Buffer address and copy the transmit data.*/
+		eprambase = (u32 __force *)(ep->udc->base_address +
+				ep->rambase + ep->ep_usb.maxpacket);
+		dst = virt_to_phys(eprambase);
+		udc->write_fn(ep->udc->base_address, ep->offset +
+				XUSB_EP_BUF1COUNT_OFFSET, length);
+		udc->write_fn(udc->base_address, XUSB_DMA_CONTROL_OFFSET,
+				XUSB_DMA_BRR_CTRL | (1 << (ep->epnumber +
+				XUSB_STATUS_EP_BUFF2_SHIFT)));
+		ep->buffer1ready = 1;
+		ep->curbufnum = 0;
+	} else {
+		/* None of ping pong buffers are ready currently .*/
+		return -EAGAIN;
+	}
+
+	ret = xudc_start_dma(ep, src, dst, length);
+	return ret;
+}
+
+/**
+ * xudc_dma_receive - Receives OUT data using DMA.
+ * @ep: pointer to the usb device endpoint structure.
+ * @req: pointer to the usb request structure.
+ * @buffer: pointer to storage buffer of received data.
+ * @length: number of bytes to receive.
+ *
+ * Return: 0 on success, -EAGAIN if no buffer is free and error
+ *	   code on failure.
+ *
+ * This function receives data using DMA.
+ */
+static int xudc_dma_receive(struct xusb_ep *ep, struct xusb_req *req,
+				u8 *buffer, u32 length)
+{
+	u32 *eprambase;
+	dma_addr_t src;
+	dma_addr_t dst;
+	int ret = 0;
+	struct xusb_udc *udc = ep->udc;
+
+	dst = req->usb_req.dma + req->usb_req.actual;
+
+	if (!ep->curbufnum && !ep->buffer0ready) {
+		/* Get the Buffer address and copy the transmit data */
+		eprambase = (u32 __force *)(ep->udc->base_address +
+				ep->rambase);
+		src = virt_to_phys(eprambase);
+		udc->write_fn(udc->base_address, XUSB_DMA_CONTROL_OFFSET,
+				XUSB_DMA_BRR_CTRL | XUSB_DMA_READ_FROM_DPRAM |
+				(1 << ep->epnumber));
+		ep->buffer0ready = 1;
+		ep->curbufnum = 1;
+	} else if (ep->curbufnum && !ep->buffer1ready) {
+		/* Get the Buffer address and copy the transmit data */
+		eprambase = (u32 __force *)(ep->udc->base_address +
+				ep->rambase + ep->ep_usb.maxpacket);
+		src = virt_to_phys(eprambase);
+		udc->write_fn(udc->base_address, XUSB_DMA_CONTROL_OFFSET,
+				XUSB_DMA_BRR_CTRL | XUSB_DMA_READ_FROM_DPRAM |
+				(1 << (ep->epnumber +
+				XUSB_STATUS_EP_BUFF2_SHIFT)));
+		ep->buffer1ready = 1;
+		ep->curbufnum = 0;
+	} else {
+		/* None of the ping-pong buffers are ready currently */
+		return -EAGAIN;
+	}
+
+	xudc_start_dma(ep, src, dst, length);
+	return ret;
+}
+
+/**
+ * xudc_eptxrx - Transmits or receives data to or from an endpoint.
+ * @ep: pointer to the usb endpoint configuration structure.
+ * @req: pointer to the usb request structure.
+ * @bufferptr: pointer to buffer containing the data to be sent.
+ * @bufferlen: The number of data bytes to be sent.
+ *
+ * Return: 0 on success, -EAGAIN if no buffer is free.
+ *
+ * This function copies the transmit/receive data to/from the end point buffer
+ * and enables the buffer for transmission/reception.
+ */
+static int xudc_eptxrx(struct xusb_ep *ep, struct xusb_req *req,
+			u8 *bufferptr, u32 bufferlen)
+{
+	u32 *eprambase;
+	u32 bytestosend;
+	u8 *temprambase;
+	int rc = 0;
+	struct xusb_udc *udc = ep->udc;
+
+	bytestosend = bufferlen;
+	if (udc->dma_enabled) {
+		if (ep->is_in)
+			rc = xudc_dma_send(ep, req, bufferptr, bufferlen);
+		else
+			rc = xudc_dma_receive(ep, req, bufferptr, bufferlen);
+		return rc;
+	}
+	/* Put the transmit buffer into the correct ping-pong buffer.*/
+	if (!ep->curbufnum && !ep->buffer0ready) {
+		/* Get the Buffer address and copy the transmit data.*/
+		eprambase = (u32 __force *)(udc->base_address + ep->rambase);
+		while (bytestosend > 3) {
+			if (ep->is_in)
+				*eprambase++ = *(u32 *)bufferptr;
+			else
+				*(u32 *)bufferptr = *eprambase++;
+			bufferptr += 4;
+			bytestosend -= 4;
+		}
+		temprambase = (u8 *)eprambase;
+		while (bytestosend--) {
+			if (ep->is_in)
+				*temprambase++ = *bufferptr++;
+			else
+				*bufferptr++ = *temprambase++;
+		}
+		/*
+		 * Set the Buffer count register with transmit length
+		 * and enable the buffer for transmission.
+		 */
+		if (ep->is_in)
+			udc->write_fn(udc->base_address, ep->offset +
+					XUSB_EP_BUF0COUNT_OFFSET, bufferlen);
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET,
+				1 << ep->epnumber);
+		ep->buffer0ready = 1;
+		ep->curbufnum = 1;
+	} else if ((ep->curbufnum == 1) && (!ep->buffer1ready)) {
+		/* Get the Buffer address and copy the transmit data.*/
+		eprambase = (u32 __force *)(udc->base_address + ep->rambase +
+				ep->ep_usb.maxpacket);
+		while (bytestosend > 3) {
+			if (ep->is_in)
+				*eprambase++ = *(u32 *)bufferptr;
+			else
+				*(u32 *)bufferptr = *eprambase++;
+			bufferptr += 4;
+			bytestosend -= 4;
+		}
+		temprambase = (u8 *)eprambase;
+		while (bytestosend--) {
+			if (ep->is_in)
+				*temprambase++ = *bufferptr++;
+			else
+				*bufferptr++ = *temprambase++;
+		}
+		/*
+		 * Set the Buffer count register with transmit
+		 * length and enable the buffer for
+		 * transmission.
+		 */
+		if (ep->is_in)
+			udc->write_fn(udc->base_address, ep->offset +
+					XUSB_EP_BUF1COUNT_OFFSET, bufferlen);
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET,
+				1 << (ep->epnumber +
+				XUSB_STATUS_EP_BUFF2_SHIFT));
+		ep->buffer1ready = 1;
+		ep->curbufnum = 0;
+	} else {
+		/* None of the ping-pong buffers are ready currently */
+		return -EAGAIN;
+	}
+	return rc;
+}
+
+/**
+ * xudc_done - Exeutes the endpoint data transfer completion tasks.
+ * @ep: pointer to the usb device endpoint structure.
+ * @req: pointer to the usb request structure.
+ * @status: Status of the data transfer.
+ *
+ * Deletes the message from the queue and updates data transfer completion
+ * status.
+ */
+static void xudc_done(struct xusb_ep *ep, struct xusb_req *req, int status)
+{
+	struct xusb_udc *udc = ep->udc;
+
+	list_del_init(&req->queue);
+
+	if (req->usb_req.status == -EINPROGRESS)
+		req->usb_req.status = status;
+	else
+		status = req->usb_req.status;
+
+	if (status && status != -ESHUTDOWN)
+		dev_dbg(udc->dev, "%s done %p, status %d\n",
+				ep->ep_usb.name, req, status);
+	/* unmap request if DMA is present*/
+	if (udc->dma_enabled && ep->epnumber && req->usb_req.length)
+		usb_gadget_unmap_request(&udc->gadget, &req->usb_req,
+						ep->is_in);
+
+	if (req->usb_req.complete) {
+		spin_unlock(&udc->lock);
+		req->usb_req.complete(&ep->ep_usb, &req->usb_req);
+		spin_lock(&udc->lock);
+	}
+}
+
+/**
+ * xudc_read_fifo - Reads the data from the given endpoint buffer.
+ * @ep: pointer to the usb device endpoint structure.
+ * @req: pointer to the usb request structure.
+ *
+ * Return: 0 if request is completed and -EAGAIN if not completed.
+ *
+ * Pulls OUT packet data from the endpoint buffer.
+ */
+static int xudc_read_fifo(struct xusb_ep *ep, struct xusb_req *req)
+{
+	u8 *buf;
+	u32 is_short, count, bufferspace;
+	u8 bufoffset;
+	u8 two_pkts = 0;
+	int ret;
+	int retval = -EAGAIN;
+	struct xusb_udc *udc = ep->udc;
+
+	if ((ep->buffer0ready == 1) && (ep->buffer1ready == 1)) {
+		dev_dbg(udc->dev, "Packet NOT ready!\n");
+		return retval;
+	}
+top:
+	if (ep->curbufnum)
+		bufoffset = XUSB_EP_BUF1COUNT_OFFSET;
+	else
+		bufoffset = XUSB_EP_BUF0COUNT_OFFSET;
+
+	count = udc->read_fn(udc->base_address + ep->offset + bufoffset);
+
+	if (!ep->buffer0ready && !ep->buffer1ready)
+		two_pkts = 1;
+
+	buf = req->usb_req.buf + req->usb_req.actual;
+	prefetchw(buf);
+	bufferspace = req->usb_req.length - req->usb_req.actual;
+	is_short = count < ep->ep_usb.maxpacket;
+
+	if (unlikely(!bufferspace)) {
+		/*
+		 * This happens when the driver's buffer
+		 * is smaller than what the host sent.
+		 * discard the extra data.
+		 */
+		if (req->usb_req.status != -EOVERFLOW)
+			dev_dbg(udc->dev,
+					"%s overflow %d\n",
+					ep->ep_usb.name, count);
+		req->usb_req.status = -EOVERFLOW;
+		xudc_done(ep, req, -EOVERFLOW);
+		return 0;
+	}
+
+	ret = xudc_eptxrx(ep, req, buf, count);
+	switch (ret) {
+	case 0:
+		req->usb_req.actual += min(count, bufferspace);
+		dev_dbg(udc->dev, "read %s, %d bytes%s req %p %d/%d\n",
+			ep->ep_usb.name, count, is_short ? "/S" : "", req,
+			req->usb_req.actual, req->usb_req.length);
+		bufferspace -= count;
+		/* Completion */
+		if ((req->usb_req.actual == req->usb_req.length) || is_short) {
+			if (udc->dma_enabled && req->usb_req.length)
+				dma_sync_single_for_cpu(udc->dev,
+							req->usb_req.dma,
+							req->usb_req.actual,
+							DMA_FROM_DEVICE);
+			xudc_done(ep, req, 0);
+			return 0;
+		}
+		if (two_pkts) {
+			two_pkts = 0;
+			goto top;
+		}
+		break;
+	case -EAGAIN:
+		dev_dbg(udc->dev, "receive busy\n");
+		break;
+	case -EINVAL:
+	case -ETIMEDOUT:
+		/* DMA error, dequeue the request */
+		xudc_done(ep, req, -ECONNRESET);
+		retval = 0;
+		break;
+	}
+
+	return retval;
+}
+
+/**
+ * xudc_write_fifo - Writes data into the given endpoint buffer.
+ * @ep: pointer to the usb device endpoint structure.
+ * @req: pointer to the usb request structure.
+ *
+ * Return: 0 if request is completed and -EAGAIN if not completed.
+ *
+ * Loads endpoint buffer for an IN packet.
+ */
+static int xudc_write_fifo(struct xusb_ep *ep, struct xusb_req *req)
+{
+	u32 max;
+	u32 length;
+	int ret;
+	int retval = -EAGAIN;
+	struct xusb_udc *udc = ep->udc;
+	int is_last, is_short = 0;
+	u8 *buf;
+
+	max = le16_to_cpu(ep->desc->wMaxPacketSize);
+	buf = req->usb_req.buf + req->usb_req.actual;
+	prefetch(buf);
+	length = req->usb_req.length - req->usb_req.actual;
+	length = min(length, max);
+
+	ret = xudc_eptxrx(ep, req, buf, length);
+	switch (ret) {
+	case 0:
+		req->usb_req.actual += length;
+		if (unlikely(length != max)) {
+			is_last = is_short = 1;
+		} else {
+			if (likely(req->usb_req.length !=
+				   req->usb_req.actual) || req->usb_req.zero)
+				is_last = 0;
+			else
+				is_last = 1;
+		}
+		dev_dbg(udc->dev,
+			"%s: wrote %s %d bytes%s%s %d left %p\n", __func__,
+			ep->ep_usb.name, length, is_last ? "/L" : "",
+			is_short ? "/S" : "",
+			req->usb_req.length - req->usb_req.actual, req);
+		/* completion */
+		if (is_last) {
+			xudc_done(ep, req, 0);
+			retval = 0;
+		}
+		break;
+	case -EAGAIN:
+		dev_dbg(udc->dev, "Send busy\n");
+		break;
+	case -EINVAL:
+	case -ETIMEDOUT:
+		/* DMA error, dequeue the request */
+		xudc_done(ep, req, -ECONNRESET);
+		retval = 0;
+		break;
+	}
+
+	return retval;
+}
+
+/**
+ * xudc_nuke - Cleans up the data transfer message list.
+ * @ep: pointer to the usb device endpoint structure.
+ * @status: Status of the data transfer.
+ */
+static void xudc_nuke(struct xusb_ep *ep, int status)
+{
+	struct xusb_req *req;
+
+	while (!list_empty(&ep->queue)) {
+		req = list_first_entry(&ep->queue, struct xusb_req, queue);
+		xudc_done(ep, req, status);
+	}
+}
+
+/**
+ * xudc_ep_set_halt - Stalls/unstalls the given endpoint.
+ * @_ep: pointer to the usb device endpoint structure.
+ * @value: value to indicate stall/unstall.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep_set_halt(struct usb_ep *_ep, int value)
+{
+	struct xusb_ep *ep = to_xusb_ep(_ep);
+	struct xusb_udc *udc;
+	unsigned long flags;
+	u32 epcfgreg;
+
+	if (!_ep || (!ep->desc && ep->epnumber)) {
+		pr_debug("%s: bad ep or descriptor\n", __func__);
+		return -EINVAL;
+	}
+	udc = ep->udc;
+
+	if (ep->is_in && (!list_empty(&ep->queue)) && value) {
+		dev_dbg(udc->dev, "requests pending can't halt\n");
+		return -EAGAIN;
+	}
+
+	if ((ep->buffer0ready == 1) || (ep->buffer1ready == 1)) {
+		dev_dbg(udc->dev, "HW buffers busy can't halt\n");
+		return -EAGAIN;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	if (value) {
+		/* Stall the device.*/
+		epcfgreg = udc->read_fn(udc->base_address + ep->offset);
+		epcfgreg |= XUSB_EP_CFG_STALL_MASK;
+
+		udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+	} else {
+		/* Unstall the device.*/
+		epcfgreg = udc->read_fn(udc->base_address + ep->offset);
+		epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
+		udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+		if (ep->epnumber) {
+			/* Reset the toggle bit.*/
+			epcfgreg = udc->read_fn(ep->udc->base_address +
+						    ep->offset);
+			epcfgreg &= ~XUSB_EP_CFG_DATA_TOGGLE_MASK;
+			udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+		}
+	}
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return 0;
+}
+
+/**
+ * xudc_ep_enable - Enables the given endpoint.
+ * @ep: pointer to the xusb endpoint structure.
+ * @desc: pointer to usb endpoint descriptor.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int __xudc_ep_enable(struct xusb_ep *ep,
+			  const struct usb_endpoint_descriptor *desc)
+{
+	struct xusb_udc *udc = ep->udc;
+	u32 tmp;
+	u8 eptype = 0;
+	u32 epcfg;
+	u32 ier;
+
+	ep->is_in = ((desc->bEndpointAddress & USB_DIR_IN) != 0);
+	/* Bit 3...0:endpoint number */
+	ep->epnumber = (desc->bEndpointAddress & 0x0f);
+	ep->desc = desc;
+	ep->ep_usb.desc = desc;
+	tmp = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
+	ep->ep_usb.maxpacket = le16_to_cpu(desc->wMaxPacketSize);
+
+	switch (tmp) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		dev_dbg(udc->dev, "only one control endpoint\n");
+		/* NON- ISO */
+		eptype = 0;
+		return -EINVAL;
+	case USB_ENDPOINT_XFER_INT:
+		/* NON- ISO */
+		eptype = 0;
+		if (ep->ep_usb.maxpacket > 64)
+			goto bogus_max;
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		/* NON- ISO */
+		eptype = 0;
+		switch (ep->ep_usb.maxpacket) {
+		case 8:
+		case 16:
+		case 32:
+		case 64:
+		case 512:
+			goto ok;
+		}
+bogus_max:
+		dev_dbg(udc->dev, "bogus maxpacket %d\n",
+			ep->ep_usb.maxpacket);
+		return -EINVAL;
+	case USB_ENDPOINT_XFER_ISOC:
+		/* ISO */
+		eptype = 1;
+		ep->is_iso = 1;
+		break;
+	}
+ok:
+	ep->eptype = eptype;
+	ep->buffer0ready = 0;
+	ep->buffer1ready = 0;
+	ep->curbufnum = 0;
+	ep->rambase = rambase[ep->epnumber];
+	xudc_epconfig(ep, udc);
+
+	dev_dbg(udc->dev, "Enable Endpoint %d max pkt is %d\n",
+		ep->epnumber, ep->ep_usb.maxpacket);
+
+	/* Enable the End point.*/
+	epcfg = udc->read_fn(udc->base_address + ep->offset);
+	epcfg |= XUSB_EP_CFG_VALID_MASK;
+	udc->write_fn(udc->base_address, ep->offset, epcfg);
+	if (ep->epnumber)
+		ep->rambase <<= 2;
+
+	/* Enable buffer completion interrupts for endpoint */
+	ier = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+	ier |= (XUSB_STATUS_INTR_BUFF_COMP_SHIFT_MASK << ep->epnumber);
+	udc->write_fn(udc->base_address, XUSB_IER_OFFSET, ier);
+
+	/* for OUT endpoint set buffers ready to receive */
+	if (ep->epnumber && !ep->is_in) {
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET,
+				1 << ep->epnumber);
+		ep->buffer0ready = 1;
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET,
+				(1 << (ep->epnumber +
+				XUSB_STATUS_EP_BUFF2_SHIFT)));
+		ep->buffer1ready = 1;
+	}
+
+	return 0;
+}
+
+/**
+ * xudc_ep_enable - Enables the given endpoint.
+ * @_ep: pointer to the usb endpoint structure.
+ * @desc: pointer to usb endpoint descriptor.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep_enable(struct usb_ep *_ep,
+			  const struct usb_endpoint_descriptor *desc)
+{
+	struct xusb_ep *ep;
+	struct xusb_udc *udc;
+	unsigned long flags;
+	int ret;
+
+	if (!_ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
+		pr_debug("%s: bad ep or descriptor\n", __func__);
+		return -EINVAL;
+	}
+
+	ep = to_xusb_ep(_ep);
+	udc = ep->udc;
+
+	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
+		dev_dbg(udc->dev, "bogus device state\n");
+		return -ESHUTDOWN;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+	ret = __xudc_ep_enable(ep, desc);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return ret;
+}
+
+/**
+ * xudc_ep_disable - Disables the given endpoint.
+ * @_ep: pointer to the usb endpoint structure.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep_disable(struct usb_ep *_ep)
+{
+	struct xusb_ep *ep;
+	unsigned long flags;
+	u32 epcfg;
+	struct xusb_udc *udc;
+
+	if (!_ep) {
+		pr_debug("%s: invalid ep\n", __func__);
+		return -EINVAL;
+	}
+
+	ep = to_xusb_ep(_ep);
+	udc = ep->udc;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	xudc_nuke(ep, -ESHUTDOWN);
+
+	/* Restore the endpoint's pristine config */
+	ep->desc = NULL;
+	ep->ep_usb.desc = NULL;
+
+	dev_dbg(udc->dev, "USB Ep %d disable\n ", ep->epnumber);
+	/* Disable the endpoint.*/
+	epcfg = udc->read_fn(udc->base_address + ep->offset);
+	epcfg &= ~XUSB_EP_CFG_VALID_MASK;
+	udc->write_fn(udc->base_address, ep->offset, epcfg);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return 0;
+}
+
+/**
+ * xudc_ep_alloc_request - Initializes the request queue.
+ * @_ep: pointer to the usb endpoint structure.
+ * @gfp_flags: Flags related to the request call.
+ *
+ * Return: pointer to request structure on success and a NULL on failure.
+ */
+static struct usb_request *xudc_ep_alloc_request(struct usb_ep *_ep,
+						 gfp_t gfp_flags)
+{
+	struct xusb_ep *ep = to_xusb_ep(_ep);
+	struct xusb_udc *udc;
+	struct xusb_req *req;
+
+	udc = ep->udc;
+	req = kzalloc(sizeof(*req), gfp_flags);
+	if (!req) {
+		dev_err(udc->dev, "not enough memory");
+		return NULL;
+	}
+
+	req->ep = ep;
+	INIT_LIST_HEAD(&req->queue);
+	return &req->usb_req;
+}
+
+/**
+ * xudc_free_request - Releases the request from queue.
+ * @_ep: pointer to the usb device endpoint structure.
+ * @_req: pointer to the usb request structure.
+ */
+static void xudc_free_request(struct usb_ep *_ep, struct usb_request *_req)
+{
+	struct xusb_req *req = to_xusb_req(_req);
+
+	kfree(req);
+}
+
+/**
+ * xudc_ep0_queue - Adds the request to endpoint 0 queue.
+ * @ep0: pointer to the xusb endpoint 0 structure.
+ * @req: pointer to the xusb request structure.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int __xudc_ep0_queue(struct xusb_ep *ep0, struct xusb_req *req)
+{
+	struct xusb_udc *udc = ep0->udc;
+	u32 length;
+	u8 *corebuf;
+
+	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
+		dev_dbg(udc->dev, "%s, bogus device state\n",
+			__func__);
+		return -EINVAL;
+	}
+	if (!list_empty(&ep0->queue)) {
+		dev_dbg(udc->dev, "%s:ep0 busy\n", __func__);
+		return -EBUSY;
+	}
+
+	req->usb_req.status = -EINPROGRESS;
+	req->usb_req.actual = 0;
+
+	list_add_tail(&req->queue, &ep0->queue);
+
+	if (udc->setup.bRequestType & USB_DIR_IN) {
+		prefetch(req->usb_req.buf);
+		length = req->usb_req.length;
+		corebuf = (void __force *) ((ep0->rambase << 2) +
+				udc->base_address);
+		length = req->usb_req.actual = min_t(u32, length,
+				EP0_MAX_PACKET);
+		memcpy((void *)corebuf, req->usb_req.buf, length);
+		udc->write_fn(udc->base_address, XUSB_EP_BUF0COUNT_OFFSET,
+				length);
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET, 1);
+	} else {
+		if (udc->setup.wLength) {
+			/* Enable EP0 buffer to receive data */
+			udc->write_fn(udc->base_address,
+					XUSB_EP_BUF0COUNT_OFFSET, 0);
+			udc->write_fn(udc->base_address,
+					XUSB_BUFFREADY_OFFSET, 1);
+		} else {
+			xudc_wrstatus(udc);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * xudc_ep0_queue - Adds the request to endpoint 0 queue.
+ * @_ep: pointer to the usb endpoint 0 structure.
+ * @_req: pointer to the usb request structure.
+ * @gfp_flags: Flags related to the request call.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep0_queue(struct usb_ep *_ep, struct usb_request *_req,
+			 gfp_t gfp_flags)
+{
+	struct xusb_req *req	= to_xusb_req(_req);
+	struct xusb_ep	*ep0	= to_xusb_ep(_ep);
+	struct xusb_udc *udc	= ep0->udc;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&udc->lock, flags);
+	ret = __xudc_ep0_queue(ep0, req);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return ret;
+}
+
+/**
+ * xudc_ep_queue - Adds the request to endpoint queue.
+ * @_ep: pointer to the usb endpoint structure.
+ * @_req: pointer to the usb request structure.
+ * @gfp_flags: Flags related to the request call.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
+			 gfp_t gfp_flags)
+{
+	struct xusb_req *req = to_xusb_req(_req);
+	struct xusb_ep	*ep  = to_xusb_ep(_ep);
+	struct xusb_udc *udc = ep->udc;
+	int  ret;
+	unsigned long flags;
+
+	if (!ep->desc) {
+		dev_dbg(udc->dev, "%s:queing request to disabled %s\n",
+				__func__, ep->name);
+		return -ESHUTDOWN;
+	}
+
+	if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
+		dev_dbg(udc->dev, "%s, bogus device state\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	_req->status = -EINPROGRESS;
+	_req->actual = 0;
+
+	if (udc->dma_enabled) {
+		ret = usb_gadget_map_request(&udc->gadget,
+					&req->usb_req, ep->is_in);
+		if (ret) {
+			dev_dbg(udc->dev, "gadget_map failed ep%d\n",
+					ep->epnumber);
+			spin_unlock_irqrestore(&udc->lock, flags);
+			return -EAGAIN;
+		}
+	}
+
+	/*
+	 * Start processing requests now, if IP buffers are busy with
+	 * previous transactions or data is more than max packet
+	 * size then add requests to queue otherwise finish the work
+	 * and call completion.
+	 */
+	if (list_empty(&ep->queue)) {
+		if (ep->is_in) {
+			dev_dbg(udc->dev, "xudc_write_fifo from ep_queue\n");
+			if (!xudc_write_fifo(ep, req))
+				req = NULL;
+		} else {
+			dev_dbg(udc->dev, "xudc_read_fifo from ep_queue\n");
+			if (!xudc_read_fifo(ep, req))
+				req = NULL;
+		}
+	}
+
+	if (req != NULL)
+		list_add_tail(&req->queue, &ep->queue);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return 0;
+}
+
+/**
+ * xudc_ep_dequeue - Removes the request from the queue.
+ * @_ep: pointer to the usb device endpoint structure.
+ * @_req: pointer to the usb request structure.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
+{
+	struct xusb_ep *ep	= to_xusb_ep(_ep);
+	struct xusb_req *req	= to_xusb_req(_req);
+	struct xusb_udc *udc	= ep->udc;
+	unsigned long flags;
+
+	if (ep->ep_usb.name == ep0name)
+		return -EINVAL;
+
+	spin_lock_irqsave(&udc->lock, flags);
+	/* Make sure it's actually queued on this endpoint */
+	list_for_each_entry(req, &ep->queue, queue) {
+		if (&req->usb_req == _req)
+			break;
+	}
+	if (&req->usb_req != _req) {
+		spin_unlock_irqrestore(&ep->udc->lock, flags);
+		return -EINVAL;
+	}
+	xudc_done(ep, req, -ECONNRESET);
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+}
+
+/**
+ * xudc_ep0_enable - Enables the given endpoint.
+ * @ep: pointer to the usb endpoint structure.
+ * @desc: pointer to usb endpoint descriptor.
+ *
+ * Return: error always.
+ *
+ * endpoint 0 enable should not be called by gadget layer.
+ */
+static int xudc_ep0_enable(struct usb_ep *ep,
+		const struct usb_endpoint_descriptor *desc)
+{
+	return -EINVAL;
+}
+
+/**
+ * xudc_ep0_disable - Disables the given endpoint.
+ * @ep: pointer to the usb endpoint structure.
+ *
+ * Return: error always.
+ *
+ * endpoint 0 disable should not be called by gadget layer.
+ */
+static int xudc_ep0_disable(struct usb_ep *ep)
+{
+	return -EINVAL;
+}
+
+static const struct usb_ep_ops xusb_ep0_ops = {
+	.enable		= xudc_ep0_enable,
+	.disable	= xudc_ep0_disable,
+	.alloc_request	= xudc_ep_alloc_request,
+	.free_request	= xudc_free_request,
+	.queue		= xudc_ep0_queue,
+	.dequeue	= xudc_ep_dequeue,
+	.set_halt	= xudc_ep_set_halt,
+};
+
+static const struct usb_ep_ops xusb_ep_ops = {
+	.enable		= xudc_ep_enable,
+	.disable	= xudc_ep_disable,
+	.alloc_request	= xudc_ep_alloc_request,
+	.free_request	= xudc_free_request,
+	.queue		= xudc_ep_queue,
+	.dequeue	= xudc_ep_dequeue,
+	.set_halt	= xudc_ep_set_halt,
+};
+
+/**
+ * xudc_get_frame - Reads the current usb frame number.
+ * @gadget: pointer to the usb gadget structure.
+ *
+ * Return: current frame number for success and error value on failure.
+ */
+static int xudc_get_frame(struct usb_gadget *gadget)
+{
+	struct xusb_udc *udc;
+	int frame;
+
+	if (!gadget)
+		return -ENODEV;
+
+	udc = to_udc(gadget);
+	frame = udc->read_fn(udc->base_address + XUSB_FRAMENUM_OFFSET);
+	return frame;
+}
+
+/**
+ * xudc_wakeup - Send remote wakeup signal to host
+ * @gadget: pointer to the usb gadget structure.
+ *
+ * Return: 0 on success and error on failure
+ */
+static int xudc_wakeup(struct usb_gadget *gadget)
+{
+	struct xusb_udc *udc = to_udc(gadget);
+	u32 crtlreg;
+	int status = -EINVAL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/* Remote wake up not enabled by host */
+	if (!udc->remote_wkp)
+		goto done;
+
+	crtlreg = udc->read_fn(udc->base_address + XUSB_CONTROL_OFFSET);
+	crtlreg |= XUSB_CONTROL_USB_RMTWAKE_MASK;
+	/* set remote wake up bit */
+	udc->write_fn(udc->base_address, XUSB_CONTROL_OFFSET, crtlreg);
+	/*
+	 * wait for a while and reset remote wake up bit since this bit
+	 * is not cleared by HW after sending remote wakeup to host.
+	 */
+	mdelay(2);
+
+	crtlreg &= ~XUSB_CONTROL_USB_RMTWAKE_MASK;
+	udc->write_fn(udc->base_address, XUSB_CONTROL_OFFSET, crtlreg);
+	status = 0;
+done:
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return status;
+}
+
+/**
+ * xudc_pullup - start/stop USB traffic
+ * @gadget: pointer to the usb gadget structure.
+ * @is_on: flag to start or stop
+ *
+ * Return: 0 always
+ *
+ * This function starts/stops SIE engine of IP based on is_on.
+ */
+static int xudc_pullup(struct usb_gadget *gadget, int is_on)
+{
+	struct xusb_udc *udc = to_udc(gadget);
+	unsigned long flags;
+	u32 crtlreg;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	crtlreg = udc->read_fn(udc->base_address + XUSB_CONTROL_OFFSET);
+	if (is_on)
+		crtlreg |= XUSB_CONTROL_USB_READY_MASK;
+	else
+		crtlreg &= ~XUSB_CONTROL_USB_READY_MASK;
+
+	udc->write_fn(udc->base_address, XUSB_CONTROL_OFFSET, crtlreg);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+}
+
+/**
+ * xudc_eps_init - initialize endpoints.
+ * @udc: pointer to the usb device controller structure.
+ */
+static void xudc_eps_init(struct xusb_udc *udc)
+{
+	u32 ep_number;
+	char name[4];
+
+	INIT_LIST_HEAD(&udc->gadget.ep_list);
+
+	for (ep_number = 0; ep_number < XUSB_MAX_ENDPOINTS; ep_number++) {
+		struct xusb_ep *ep = &udc->ep[ep_number];
+
+		if (ep_number) {
+			list_add_tail(&ep->ep_usb.ep_list,
+					&udc->gadget.ep_list);
+			usb_ep_set_maxpacket_limit(&ep->ep_usb,
+					(unsigned short) ~0);
+			sprintf(name, "ep%d", ep_number);
+			strcpy(ep->name, name);
+			ep->ep_usb.name = ep->name;
+			ep->ep_usb.ops = &xusb_ep_ops;
+		} else {
+			ep->ep_usb.name = ep0name;
+			usb_ep_set_maxpacket_limit(&ep->ep_usb, 64);
+			ep->ep_usb.ops = &xusb_ep0_ops;
+		}
+
+		ep->udc = udc;
+		ep->epnumber = ep_number;
+		ep->desc = NULL;
+		/*
+		 * The configuration register address offset between
+		 * each endpoint is 0x10.
+		 */
+		ep->offset = XUSB_EP0_CONFIG_OFFSET +
+					(ep_number * 0x10);
+		ep->is_in = 0;
+		ep->is_iso = 0;
+		ep->maxpacket = 0;
+		xudc_epconfig(ep, udc);
+
+		/* Initialize one queue per endpoint */
+		INIT_LIST_HEAD(&ep->queue);
+	}
+}
+
+/**
+ * xudc_stop_activity - Stops any further activity on the device.
+ * @udc: pointer to the usb device controller structure.
+ */
+static void xudc_stop_activity(struct xusb_udc *udc)
+{
+	int i;
+	struct xusb_ep *ep;
+
+	for (i = 0; i < XUSB_MAX_ENDPOINTS; i++) {
+		ep = &udc->ep[i];
+		xudc_nuke(ep, -ESHUTDOWN);
+	}
+}
+
+/**
+ * xudc_start - Starts the device.
+ * @gadget: pointer to the usb gadget structure
+ * @driver: pointer to gadget driver structure
+ *
+ * Return: zero on success and error on failure
+ */
+static int xudc_start(struct usb_gadget *gadget,
+			struct usb_gadget_driver *driver)
+{
+	struct xusb_udc *udc	= to_udc(gadget);
+	struct xusb_ep *ep0	= &udc->ep[XUSB_EP_NUMBER_ZERO];
+	const struct usb_endpoint_descriptor *desc = &config_bulk_out_desc;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	if (udc->driver) {
+		dev_err(udc->dev, "%s is already bound to %s\n",
+				udc->gadget.name, udc->driver->driver.name);
+		ret = -EBUSY;
+		goto err;
+	}
+
+	/* hook up the driver */
+	udc->driver = driver;
+	udc->gadget.speed = driver->max_speed;
+
+	/* Enable the control endpoint. */
+	ret = __xudc_ep_enable(ep0, desc);
+
+	/* Set device address and remote wakeup to 0 */
+	udc->write_fn(udc->base_address, XUSB_ADDRESS_OFFSET, 0);
+	udc->remote_wkp = 0;
+err:
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return ret;
+}
+
+/**
+ * xudc_stop - stops the device.
+ * @gadget: pointer to the usb gadget structure
+ * @driver: pointer to usb gadget driver structure
+ *
+ * Return: zero always
+ */
+static int xudc_stop(struct usb_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	struct xusb_udc *udc = to_udc(gadget);
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	udc->gadget.speed = USB_SPEED_UNKNOWN;
+	udc->driver = NULL;
+
+	/* Set device address and remote wakeup to 0 */
+	udc->write_fn(udc->base_address, XUSB_ADDRESS_OFFSET, 0);
+	udc->remote_wkp = 0;
+
+	xudc_stop_activity(udc);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+}
+
+static const struct usb_gadget_ops xusb_udc_ops = {
+	.get_frame	= xudc_get_frame,
+	.wakeup		= xudc_wakeup,
+	.pullup		= xudc_pullup,
+	.udc_start	= xudc_start,
+	.udc_stop	= xudc_stop,
+};
+
+/**
+ * xudc_clear_stall_all_ep - clears stall of every endpoint.
+ * @udc: pointer to the udc structure.
+ */
+static void xudc_clear_stall_all_ep(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep;
+	u32 epcfgreg;
+	int i;
+
+	for (i = 0; i < XUSB_MAX_ENDPOINTS; i++) {
+		ep = &udc->ep[i];
+		epcfgreg = udc->read_fn(udc->base_address + ep->offset);
+		epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
+		udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+		if (ep->epnumber) {
+			/* Reset the toggle bit.*/
+			epcfgreg = udc->read_fn(ep->udc->base_address +
+						ep->offset);
+			epcfgreg &= ~XUSB_EP_CFG_DATA_TOGGLE_MASK;
+			udc->write_fn(udc->base_address, ep->offset, epcfgreg);
+		}
+	}
+}
+
+/**
+ * xudc_startup_handler - The usb device controller interrupt handler.
+ * @udc: pointer to the udc structure.
+ * @intrstatus: The mask value containing the interrupt sources.
+ *
+ * This function handles the RESET,SUSPEND,RESUME and DISCONNECT interrupts.
+ */
+static void xudc_startup_handler(struct xusb_udc *udc, u32 intrstatus)
+{
+	u32 intrreg;
+
+	if (intrstatus & XUSB_STATUS_RESET_MASK) {
+
+		dev_dbg(udc->dev, "Reset\n");
+
+		if (intrstatus & XUSB_STATUS_HIGH_SPEED_MASK)
+			udc->gadget.speed = USB_SPEED_HIGH;
+		else
+			udc->gadget.speed = USB_SPEED_FULL;
+
+		xudc_stop_activity(udc);
+		xudc_clear_stall_all_ep(udc);
+		udc->write_fn(udc->base_address, XUSB_TESTMODE_OFFSET, 0);
+
+		/* Set device address and remote wakeup to 0 */
+		udc->write_fn(udc->base_address, XUSB_ADDRESS_OFFSET, 0);
+		udc->remote_wkp = 0;
+
+		/* Enable the suspend, resume and disconnect */
+		intrreg = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+		intrreg |= XUSB_STATUS_SUSPEND_MASK | XUSB_STATUS_RESUME_MASK |
+				XUSB_STATUS_DISCONNECT_MASK;
+		udc->write_fn(udc->base_address, XUSB_IER_OFFSET, intrreg);
+	}
+	if (intrstatus & XUSB_STATUS_SUSPEND_MASK) {
+
+		dev_dbg(udc->dev, "Suspend\n");
+
+		/* Enable the reset, resume and disconnect */
+		intrreg = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+		intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_RESUME_MASK |
+				 XUSB_STATUS_DISCONNECT_MASK;
+		udc->write_fn(udc->base_address, XUSB_IER_OFFSET, intrreg);
+
+		udc->usb_state = USB_STATE_SUSPENDED;
+
+		if (udc->driver->suspend) {
+			spin_unlock(&udc->lock);
+			udc->driver->suspend(&udc->gadget);
+			spin_lock(&udc->lock);
+		}
+	}
+	if (intrstatus & XUSB_STATUS_RESUME_MASK) {
+		bool condition = (udc->usb_state != USB_STATE_SUSPENDED);
+
+		dev_WARN_ONCE(udc->dev, condition,
+				"Resume IRQ while not suspended\n");
+
+		dev_dbg(udc->dev, "Resume\n");
+
+		/* Enable the reset, suspend and disconnect */
+		intrreg = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+		intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_SUSPEND_MASK |
+				 XUSB_STATUS_DISCONNECT_MASK;
+		udc->write_fn(udc->base_address, XUSB_IER_OFFSET, intrreg);
+
+		udc->usb_state = 0;
+
+		if (udc->driver->resume) {
+			spin_unlock(&udc->lock);
+			udc->driver->resume(&udc->gadget);
+			spin_lock(&udc->lock);
+		}
+	}
+	if (intrstatus & XUSB_STATUS_DISCONNECT_MASK) {
+
+		dev_dbg(udc->dev, "Disconnect\n");
+
+		/* Enable the reset, resume and suspend */
+		intrreg = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+		intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_RESUME_MASK |
+				 XUSB_STATUS_SUSPEND_MASK;
+		udc->write_fn(udc->base_address, XUSB_IER_OFFSET, intrreg);
+
+		if (udc->driver && udc->driver->disconnect) {
+			spin_unlock(&udc->lock);
+			udc->driver->disconnect(&udc->gadget);
+			spin_lock(&udc->lock);
+		}
+	}
+}
+
+/**
+ * xudc_ep0_stall - Stall endpoint zero.
+ * @udc: pointer to the udc structure.
+ *
+ * This function stalls endpoint zero.
+ */
+static void xudc_ep0_stall(struct xusb_udc *udc)
+{
+	u32 epcfgreg;
+	struct xusb_ep *ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO];
+
+	epcfgreg = udc->read_fn(udc->base_address + ep0->offset);
+	epcfgreg |= XUSB_EP_CFG_STALL_MASK;
+	udc->write_fn(udc->base_address, ep0->offset, epcfgreg);
+}
+
+/**
+ * xudc_setaddress - executes SET_ADDRESS command
+ * @udc: pointer to the udc structure.
+ *
+ * This function executes USB SET_ADDRESS command
+ */
+static void xudc_setaddress(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0	= &udc->ep[0];
+	struct xusb_req *req	= udc->req;
+	int ret;
+
+	req->usb_req.length = 0;
+	ret = __xudc_ep0_queue(ep0, req);
+	if (ret == 0)
+		return;
+
+	dev_err(udc->dev, "Can't respond to SET ADDRESS request\n");
+	xudc_ep0_stall(udc);
+	return;
+}
+
+/**
+ * xudc_getstatus - executes GET_STATUS command
+ * @udc: pointer to the udc structure.
+ *
+ * This function executes USB GET_STATUS command
+ */
+static void xudc_getstatus(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0	= &udc->ep[0];
+	struct xusb_req *req	= udc->req;
+	struct xusb_ep *target_ep;
+	u16 status = 0;
+	u32 epcfgreg;
+	int epnum;
+	u32 halt;
+	int ret;
+
+	switch (udc->setup.bRequestType & USB_RECIP_MASK) {
+	case USB_RECIP_DEVICE:
+		/* Get device status */
+		status = 1 << USB_DEVICE_SELF_POWERED;
+		if (udc->remote_wkp)
+			status |= (1 << USB_DEVICE_REMOTE_WAKEUP);
+		break;
+	case USB_RECIP_INTERFACE:
+		break;
+	case USB_RECIP_ENDPOINT:
+		epnum = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
+		target_ep = &udc->ep[epnum];
+		epcfgreg = udc->read_fn(udc->base_address + target_ep->offset);
+		halt = epcfgreg & XUSB_EP_CFG_STALL_MASK;
+		if (udc->setup.wIndex & USB_DIR_IN) {
+			if (!target_ep->is_in)
+				goto stall;
+		} else {
+			if (target_ep->is_in)
+				goto stall;
+		}
+		if (halt)
+			status = 1 << USB_ENDPOINT_HALT;
+		break;
+	default:
+		goto stall;
+	}
+
+	req->usb_req.length = 2;
+	*(u16 *)req->usb_req.buf = cpu_to_le16(status);
+	ret = __xudc_ep0_queue(ep0, req);
+	if (ret == 0)
+		return;
+stall:
+	dev_err(udc->dev, "Can't respond to getstatus request\n");
+	xudc_ep0_stall(udc);
+	return;
+}
+
+/**
+ * xudc_set_clear_feature - Executes the set feature and clear feature commands.
+ * @udc: pointer to the usb device controller structure.
+ *
+ * Processes the SET_FEATURE and CLEAR_FEATURE commands.
+ */
+static void xudc_set_clear_feature(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0	= &udc->ep[0];
+	struct xusb_req *req	= udc->req;
+	struct xusb_ep *target_ep;
+	u8 endpoint;
+	u8 outinbit;
+	u32 epcfgreg;
+	int flag = (udc->setup.bRequest == USB_REQ_SET_FEATURE ? 1 : 0);
+	int ret;
+
+	switch (udc->setup.bRequestType) {
+	case USB_RECIP_DEVICE:
+		switch (udc->setup.wValue) {
+		case USB_DEVICE_TEST_MODE:
+			/*
+			 * The Test Mode will be executed
+			 * after the status phase.
+			 */
+			break;
+		case USB_DEVICE_REMOTE_WAKEUP:
+			if (flag)
+				udc->remote_wkp = 1;
+			else
+				udc->remote_wkp = 0;
+			break;
+		default:
+			xudc_ep0_stall(udc);
+			break;
+		}
+		break;
+	case USB_RECIP_ENDPOINT:
+		if (!udc->setup.wValue) {
+			endpoint = udc->setup.wIndex &
+					USB_ENDPOINT_NUMBER_MASK;
+			target_ep = &udc->ep[endpoint];
+			outinbit = udc->setup.wIndex &
+					USB_ENDPOINT_DIR_MASK;
+			outinbit = outinbit >> 7;
+
+			/* Make sure direction matches.*/
+			if (outinbit != target_ep->is_in) {
+				xudc_ep0_stall(udc);
+				return;
+			}
+			epcfgreg = udc->read_fn(udc->base_address +
+						target_ep->offset);
+			if (!endpoint) {
+				/* Clear the stall.*/
+				epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
+				udc->write_fn(udc->base_address,
+						target_ep->offset, epcfgreg);
+			} else {
+				if (flag) {
+					epcfgreg |= XUSB_EP_CFG_STALL_MASK;
+					udc->write_fn(udc->base_address,
+							target_ep->offset,
+							epcfgreg);
+				} else {
+					/* Unstall the endpoint.*/
+					epcfgreg &= ~(XUSB_EP_CFG_STALL_MASK |
+						  XUSB_EP_CFG_DATA_TOGGLE_MASK);
+					udc->write_fn(udc->base_address,
+							target_ep->offset,
+							epcfgreg);
+				}
+			}
+		}
+		break;
+	default:
+		xudc_ep0_stall(udc);
+		return;
+	}
+
+	req->usb_req.length = 0;
+	ret = __xudc_ep0_queue(ep0, req);
+	if (ret == 0)
+		return;
+
+	dev_err(udc->dev, "Can't respond to SET/CLEAR FEATURE\n");
+	xudc_ep0_stall(udc);
+
+	return;
+}
+
+/**
+ * xudc_handle_setup - Processes the setup packet.
+ * @udc: pointer to the usb device controller structure.
+ *
+ * Process setup packet and delegate to gadget layer.
+ */
+static void xudc_handle_setup(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0 = &udc->ep[0];
+	struct usb_ctrlrequest setup;
+	u32 *ep0rambase;
+
+	/* Load up the chapter 9 command buffer.*/
+	ep0rambase = (u32 __force *) (udc->base_address +
+				  XUSB_SETUP_PKT_ADDR_OFFSET);
+	memcpy((void *)&setup, (void *)ep0rambase, 8);
+
+	udc->setup = setup;
+
+	udc->setup.wValue = cpu_to_le16(setup.wValue);
+	udc->setup.wIndex = cpu_to_le16(setup.wIndex);
+	udc->setup.wLength = cpu_to_le16(setup.wLength);
+
+	/* Clear previous requests */
+	xudc_nuke(ep0, -ECONNRESET);
+
+	if (udc->setup.bRequestType & USB_DIR_IN) {
+		/* Execute the get command.*/
+		udc->setupseqrx = STATUS_PHASE;
+		udc->setupseqtx = DATA_PHASE;
+	} else {
+		/* Execute the put command.*/
+		udc->setupseqrx = DATA_PHASE;
+		udc->setupseqtx = STATUS_PHASE;
+	}
+
+	switch (udc->setup.bRequest) {
+	case USB_REQ_GET_STATUS:
+		/* Data+Status phase form udc */
+		if ((udc->setup.bRequestType &
+				(USB_DIR_IN | USB_TYPE_MASK)) !=
+				(USB_DIR_IN | USB_TYPE_STANDARD))
+			break;
+		xudc_getstatus(udc);
+		return;
+	case USB_REQ_SET_ADDRESS:
+		/* Status phase from udc */
+		if (udc->setup.bRequestType != (USB_DIR_OUT |
+				USB_TYPE_STANDARD | USB_RECIP_DEVICE))
+			break;
+		xudc_setaddress(udc);
+		return;
+	case USB_REQ_CLEAR_FEATURE:
+	case USB_REQ_SET_FEATURE:
+		/* Requests with no data phase, status phase from udc */
+		if ((udc->setup.bRequestType & USB_TYPE_MASK)
+				!= USB_TYPE_STANDARD)
+			break;
+		xudc_set_clear_feature(udc);
+		return;
+	default:
+		break;
+	}
+
+	spin_unlock(&udc->lock);
+	if (udc->driver->setup(&udc->gadget, &setup) < 0)
+		xudc_ep0_stall(udc);
+	spin_lock(&udc->lock);
+}
+
+/**
+ * xudc_ep0_out - Processes the endpoint 0 OUT token.
+ * @udc: pointer to the usb device controller structure.
+ */
+static void xudc_ep0_out(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0 = &udc->ep[0];
+	struct xusb_req *req;
+	u8 *ep0rambase;
+	unsigned int bytes_to_rx;
+	void *buffer;
+
+	req = list_first_entry(&ep0->queue, struct xusb_req, queue);
+
+	switch (udc->setupseqrx) {
+	case STATUS_PHASE:
+		/*
+		 * This resets both state machines for the next
+		 * Setup packet.
+		 */
+		udc->setupseqrx = SETUP_PHASE;
+		udc->setupseqtx = SETUP_PHASE;
+		req->usb_req.actual = req->usb_req.length;
+		xudc_done(ep0, req, 0);
+		break;
+	case DATA_PHASE:
+		bytes_to_rx = udc->read_fn(udc->base_address +
+				XUSB_EP_BUF0COUNT_OFFSET);
+		/* Copy the data to be received from the DPRAM. */
+		ep0rambase = (u8 __force *) (udc->base_address +
+				(ep0->rambase << 2));
+
+		buffer = req->usb_req.buf + req->usb_req.actual;
+		req->usb_req.actual = req->usb_req.actual + bytes_to_rx;
+		memcpy(buffer, (void *)ep0rambase, bytes_to_rx);
+
+		if (req->usb_req.length == req->usb_req.actual) {
+			/* Data transfer completed get ready for Status stage */
+			xudc_wrstatus(udc);
+		} else {
+			/* Enable EP0 buffer to receive data */
+			udc->write_fn(udc->base_address,
+					XUSB_EP_BUF0COUNT_OFFSET, 0);
+			udc->write_fn(udc->base_address,
+					XUSB_BUFFREADY_OFFSET, 1);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+/**
+ * xudc_ep0_in - Processes the endpoint 0 IN token.
+ * @udc: pointer to the usb device controller structure.
+ */
+static void xudc_ep0_in(struct xusb_udc *udc)
+{
+	struct xusb_ep *ep0 = &udc->ep[0];
+	struct xusb_req *req;
+	unsigned int bytes_to_tx;
+	void *buffer;
+	u32 epcfgreg;
+	u16 count = 0;
+	u16 length;
+	u8 *ep0rambase;
+	u8 test_mode = udc->setup.wIndex >> 8;
+
+	req = list_first_entry(&ep0->queue, struct xusb_req, queue);
+	bytes_to_tx = req->usb_req.length - req->usb_req.actual;
+
+	switch (udc->setupseqtx) {
+	case STATUS_PHASE:
+		switch (udc->setup.bRequest) {
+		case USB_REQ_SET_ADDRESS:
+			/* Set the address of the device.*/
+			udc->write_fn(udc->base_address,
+					XUSB_ADDRESS_OFFSET,
+					udc->setup.wValue);
+			break;
+		case USB_REQ_SET_FEATURE:
+			if (udc->setup.bRequestType ==
+					USB_RECIP_DEVICE) {
+				if (udc->setup.wValue ==
+						USB_DEVICE_TEST_MODE)
+					udc->write_fn(udc->base_address,
+							XUSB_TESTMODE_OFFSET,
+							test_mode);
+			}
+			break;
+		}
+		req->usb_req.actual = req->usb_req.length;
+		xudc_done(ep0, req, 0);
+		break;
+	case DATA_PHASE:
+		if (!bytes_to_tx) {
+			/*
+			 * We're done with data transfer, next
+			 * will be zero length OUT with data toggle of
+			 * 1. Setup data_toggle.
+			 */
+			epcfgreg = udc->read_fn(udc->base_address +
+					ep0->offset);
+			epcfgreg |= XUSB_EP_CFG_DATA_TOGGLE_MASK;
+			udc->write_fn(udc->base_address, ep0->offset, epcfgreg);
+			udc->setupseqtx = STATUS_PHASE;
+		} else {
+			length = count = min_t(u32, bytes_to_tx,
+						EP0_MAX_PACKET);
+			/* Copy the data to be transmitted into the DPRAM. */
+			ep0rambase = (u8 __force *) (udc->base_address +
+					(ep0->rambase << 2));
+
+			buffer = req->usb_req.buf + req->usb_req.actual;
+			req->usb_req.actual = req->usb_req.actual + length;
+			memcpy((void *)ep0rambase, buffer, length);
+		}
+		udc->write_fn(udc->base_address, XUSB_EP_BUF0COUNT_OFFSET,
+				count);
+		udc->write_fn(udc->base_address, XUSB_BUFFREADY_OFFSET, 1);
+		break;
+	default:
+		break;
+	}
+}
+
+/**
+ * xudc_ctrl_ep_handler - Endpoint 0 interrupt handler.
+ * @udc: pointer to the udc structure.
+ * @intrstatus:	It's the mask value for the interrupt sources on endpoint 0.
+ *
+ * Processes the commands received during enumeration phase.
+ */
+static void xudc_ctrl_ep_handler(struct xusb_udc *udc, u32 intrstatus)
+{
+
+	if (intrstatus & XUSB_STATUS_SETUP_PACKET_MASK) {
+		xudc_handle_setup(udc);
+	} else {
+		if (intrstatus & XUSB_STATUS_FIFO_BUFF_RDY_MASK)
+			xudc_ep0_out(udc);
+		else if (intrstatus & XUSB_STATUS_FIFO_BUFF_FREE_MASK)
+			xudc_ep0_in(udc);
+	}
+}
+
+/**
+ * xudc_nonctrl_ep_handler - Non control endpoint interrupt handler.
+ * @udc: pointer to the udc structure.
+ * @epnum: End point number for which the interrupt is to be processed
+ * @intrstatus:	mask value for interrupt sources of endpoints other
+ *		than endpoint 0.
+ *
+ * Processes the buffer completion interrupts.
+ */
+static void xudc_nonctrl_ep_handler(struct xusb_udc *udc, u8 epnum,
+					u32 intrstatus)
+{
+
+	struct xusb_req *req;
+	struct xusb_ep *ep;
+
+	ep = &udc->ep[epnum];
+	/* Process the End point interrupts.*/
+	if (intrstatus & (XUSB_STATUS_EP0_BUFF1_COMP_MASK << epnum))
+		ep->buffer0ready = 0;
+	if (intrstatus & (XUSB_STATUS_EP0_BUFF2_COMP_MASK << epnum))
+		ep->buffer1ready = 0;
+
+	if (list_empty(&ep->queue))
+		return;
+
+	req = list_first_entry(&ep->queue, struct xusb_req, queue);
+
+	if (ep->is_in)
+		xudc_write_fifo(ep, req);
+	else
+		xudc_read_fifo(ep, req);
+}
+
+/**
+ * xudc_irq - The main interrupt handler.
+ * @irq: The interrupt number.
+ * @_udc: pointer to the usb device controller structure.
+ *
+ * Return: IRQ_HANDLED after the interrupt is handled.
+ */
+static irqreturn_t xudc_irq(int irq, void *_udc)
+{
+	struct xusb_udc *udc = _udc;
+	u32 intrstatus;
+	u32 ier;
+	u8 index;
+	u32 bufintr;
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/*
+	 * Event interrupts are level sensitive hence first disable
+	 * IER, read ISR and figure out active interrupts.
+	 */
+	ier = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+	ier &= ~XUSB_STATUS_INTR_EVENT_MASK;
+	udc->write_fn(udc->base_address, XUSB_IER_OFFSET, ier);
+
+	/* Read the Interrupt Status Register.*/
+	intrstatus = udc->read_fn(udc->base_address + XUSB_STATUS_OFFSET);
+
+	/* Call the handler for the event interrupt.*/
+	if (intrstatus & XUSB_STATUS_INTR_EVENT_MASK) {
+		/*
+		 * Check if there is any action to be done for :
+		 * - USB Reset received {XUSB_STATUS_RESET_MASK}
+		 * - USB Suspend received {XUSB_STATUS_SUSPEND_MASK}
+		 * - USB Resume received {XUSB_STATUS_RESUME_MASK}
+		 * - USB Disconnect received {XUSB_STATUS_DISCONNECT_MASK}
+		 */
+		xudc_startup_handler(udc, intrstatus);
+	}
+
+	/* Check the buffer completion interrupts */
+	if (intrstatus & XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK) {
+		/* Enable Reset, Suspend, Resume and Disconnect  */
+		ier = udc->read_fn(udc->base_address + XUSB_IER_OFFSET);
+		ier |= XUSB_STATUS_INTR_EVENT_MASK;
+		udc->write_fn(udc->base_address, XUSB_IER_OFFSET, ier);
+
+		if (intrstatus & XUSB_STATUS_EP0_BUFF1_COMP_MASK)
+			xudc_ctrl_ep_handler(udc, intrstatus);
+
+		for (index = 1; index < 8; index++) {
+			bufintr = ((intrstatus &
+					(XUSB_STATUS_EP1_BUFF1_COMP_MASK <<
+							(index - 1))) ||
+				   (intrstatus &
+					(XUSB_STATUS_EP1_BUFF2_COMP_MASK <<
+							(index - 1))));
+			if (bufintr) {
+				xudc_nonctrl_ep_handler(udc, index,
+						intrstatus);
+			}
+		}
+	}
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+	return IRQ_HANDLED;
+}
+
+/**
+ * xudc_probe - The device probe function for driver initialization.
+ * @pdev: pointer to the platform device structure.
+ *
+ * Return: 0 for success and error value on failure
+ */
+static int xudc_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res;
+	struct xusb_udc *udc;
+	struct xusb_ep *ep0;
+	int irq;
+	int ret;
+	u32 ier;
+	u8 *buff;
+
+	udc = devm_kzalloc(&pdev->dev, sizeof(*udc), GFP_KERNEL);
+	if (!udc)
+		return -ENOMEM;
+
+	/* Map the registers */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	udc->base_address = devm_ioremap_resource(&pdev->dev, res);
+	if (!udc->base_address)
+		return -ENOMEM;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "unable to get irq\n");
+		return irq;
+	}
+	ret = devm_request_irq(&pdev->dev, irq, xudc_irq, 0,
+				dev_name(&pdev->dev), udc);
+	if (ret < 0) {
+		dev_dbg(&pdev->dev, "unable to request irq %d", irq);
+		goto fail;
+	}
+
+	udc->dma_enabled = of_property_read_bool(np, "xlnx,has-builtin-dma");
+
+	/* Setup gadget structure */
+	udc->gadget.ops = &xusb_udc_ops;
+	udc->gadget.max_speed = USB_SPEED_HIGH;
+	udc->gadget.speed = USB_SPEED_UNKNOWN;
+	udc->gadget.ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO].ep_usb;
+	udc->gadget.name = driver_name;
+
+	spin_lock_init(&udc->lock);
+
+	/* Check for IP endianness */
+	udc->write_fn = xudc_write32_be;
+	udc->read_fn = xudc_read32_be;
+	udc->write_fn(udc->base_address, XUSB_TESTMODE_OFFSET, TEST_J);
+	if ((udc->read_fn(udc->base_address + XUSB_TESTMODE_OFFSET))
+			!= TEST_J) {
+		udc->write_fn = xudc_write32;
+		udc->read_fn = xudc_read32;
+	}
+	udc->write_fn(udc->base_address, XUSB_TESTMODE_OFFSET, 0);
+
+	xudc_eps_init(udc);
+
+	ep0 = &udc->ep[0];
+	/* Create a dummy request for GET_STATUS, SET_ADDRESS */
+	udc->req = container_of(xudc_ep_alloc_request(&ep0->ep_usb, GFP_KERNEL),
+					struct xusb_req, usb_req);
+	if (!udc->req) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* buffer for data of get_status request */
+	buff = kzalloc(2, GFP_KERNEL);
+	if (buff == NULL) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	/* Dummy request ready, free this in remove */
+	udc->req->usb_req.buf = buff;
+
+	/* Set device address to 0.*/
+	udc->write_fn(udc->base_address, XUSB_ADDRESS_OFFSET, 0);
+
+	ret = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
+	if (ret)
+		goto fail;
+
+	udc->dev = &udc->gadget.dev;
+
+	/* Enable the interrupts.*/
+	ier = XUSB_STATUS_GLOBAL_INTR_MASK | XUSB_STATUS_INTR_EVENT_MASK |
+		XUSB_STATUS_FIFO_BUFF_RDY_MASK |
+		XUSB_STATUS_FIFO_BUFF_FREE_MASK |
+		XUSB_STATUS_SETUP_PACKET_MASK |
+		XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK;
+
+	udc->write_fn(udc->base_address, XUSB_IER_OFFSET, ier);
+
+	platform_set_drvdata(pdev, udc);
+
+	dev_dbg(&pdev->dev, "%s at 0x%08X mapped to 0x%08X %s\n",
+		driver_name, (u32)res->start,
+		(u32 __force)udc->base_address,
+		udc->dma_enabled ? "with DMA" : "without DMA");
+
+	return 0;
+fail:
+	dev_err(&pdev->dev, "probe failed, %d\n", ret);
+	return ret;
+}
+
+/**
+ * xudc_remove - Releases the resources allocated during the initialization.
+ * @pdev: pointer to the platform device structure.
+ *
+ * Return: 0 always
+ */
+static int xudc_remove(struct platform_device *pdev)
+{
+	struct xusb_udc *udc = platform_get_drvdata(pdev);
+	void *buf = udc->req->usb_req.buf;
+
+	usb_del_gadget_udc(&udc->gadget);
+
+	/* free memory allocated for dummy request buffer */
+	kfree(buf);
+	/* free memory allocated for dummy request */
+	kfree(udc->req);
+
+	return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id usb_of_match[] = {
+	{ .compatible = "xlnx,xps-usb2-device-4.00.a", },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, usb_of_match);
+
+static struct platform_driver xudc_driver = {
+	.driver = {
+		.name = driver_name,
+		.owner = THIS_MODULE,
+		.of_match_table = usb_of_match,
+	},
+	.probe = xudc_probe,
+	.remove = xudc_remove,
+};
+
+module_platform_driver(xudc_driver);
+
+MODULE_DESCRIPTION("Xilinx udc driver");
+MODULE_AUTHOR("Xilinx, Inc");
+MODULE_LICENSE("GPL");
-- 
1.7.4


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