usb: isp1760: Add device controller support

The ISP1761 is a dual-mode host and device controller backward
compatible on the host side with the ISP1760. Add support for the device
controller.

Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

drivers/usb/gadget/udc/Kconfig

···
           Select this to support Aeroflex Gaisler GRUSBDC cores from the GRLIB
 	  VHDL IP core library.
 
+config USB_ISP1761_UDC
+	boolean "NXP ISP1761 USB Device Controller"
+	depends on USB_ISP1760_HCD
+	help
+	   The NXP ISP1761 is a dual-role high-speed USB host and device
+	   controller.
+
 config USB_OMAP
 	tristate "OMAP USB Device Controller"
 	depends on ARCH_OMAP1

drivers/usb/host/Makefile

···
 CFLAGS_xhci-trace.o := -I$(src)
 
 isp1760-y := isp1760-core.o isp1760-hcd.o isp1760-if.o
+isp1760-$(CONFIG_USB_ISP1761_UDC) += isp1760-udc.o
 
 fhci-y := fhci-hcd.o fhci-hub.o fhci-q.o
 fhci-y += fhci-mem.o fhci-tds.o fhci-sched.o

drivers/usb/host/isp1760-core.c

···
 #include "isp1760-core.h"
 #include "isp1760-hcd.h"
 #include "isp1760-regs.h"
+#include "isp1760-udc.h"
 
 static void isp1760_init_core(struct isp1760_device *isp)
 {
+	u32 otgctrl;
 	u32 hwmode;
 
 	/* Low-level chip reset */
···
 		hwmode |= HW_INTR_EDGE_TRIG;
 
 	/*
+	 * The ISP1761 has a dedicated DC IRQ line but supports sharing the HC
+	 * IRQ line for both the host and device controllers. Hardcode IRQ
+	 * sharing for now and disable the DC interrupts globally to avoid
+	 * spurious interrupts during HCD registration.
+	 */
+	if (isp->devflags & ISP1760_FLAG_ISP1761) {
+		isp1760_write32(isp->regs, DC_MODE, 0);
+		hwmode |= HW_COMN_IRQ;
+	}
+
+	/*
 	 * We have to set this first in case we're in 16-bit mode.
 	 * Write it twice to ensure correct upper bits if switching
 	 * to 16-bit mode.
···
 	isp1760_write32(isp->regs, HC_HW_MODE_CTRL, hwmode);
 
 	/*
-	 * PORT 1 Control register of the ISP1760 is the OTG control register on
-	 * ISP1761. Since there is no OTG or device controller support in this
-	 * driver, we use port 1 as a "normal" USB host port on both chips.
+	 * PORT 1 Control register of the ISP1760 is the OTG control register
+	 * on ISP1761.
+	 *
+	 * TODO: Really support OTG. For now we configure port 1 in device mode
+	 * when OTG is requested.
 	 */
-	isp1760_write32(isp->regs, HC_PORT1_CTRL, PORT1_POWER | PORT1_INIT2);
-	usleep_range(10000, 11000);
+	if ((isp->devflags & ISP1760_FLAG_ISP1761) &&
+	    (isp->devflags & ISP1760_FLAG_OTG_EN))
+		otgctrl = ((HW_DM_PULLDOWN | HW_DP_PULLDOWN) << 16)
+			| HW_OTG_DISABLE;
+	else
+		otgctrl = (HW_SW_SEL_HC_DC << 16)
+			| (HW_VBUS_DRV | HW_SEL_CP_EXT);
+
+	isp1760_write32(isp->regs, HC_PORT1_CTRL, otgctrl);
 
 	dev_info(isp->dev, "bus width: %u, oc: %s\n",
 		 isp->devflags & ISP1760_FLAG_BUS_WIDTH_16 ? 16 : 32,
 		 isp->devflags & ISP1760_FLAG_ANALOG_OC ? "analog" : "digital");
+}
+
+void isp1760_set_pullup(struct isp1760_device *isp, bool enable)
+{
+	isp1760_write32(isp->regs, HW_OTG_CTRL_SET,
+			enable ? HW_DP_PULLUP : HW_DP_PULLUP << 16);
 }
 
 int isp1760_register(struct resource *mem, int irq, unsigned long irqflags,
···
 	if (ret < 0)
 		return ret;
 
+	if (devflags & ISP1760_FLAG_ISP1761) {
+		ret = isp1760_udc_register(isp, irq, irqflags | IRQF_SHARED |
+					   IRQF_DISABLED);
+		if (ret < 0) {
+			isp1760_hcd_unregister(&isp->hcd);
+			return ret;
+		}
+	}
+
 	dev_set_drvdata(dev, isp);
 
 	return 0;
···
 void isp1760_unregister(struct device *dev)
 {
 	struct isp1760_device *isp = dev_get_drvdata(dev);
+
+	if (isp->devflags & ISP1760_FLAG_ISP1761)
+		isp1760_udc_unregister(isp);
 
 	isp1760_hcd_unregister(&isp->hcd);
 }

drivers/usb/host/isp1760-core.h

···
 #include <linux/ioport.h>
 
 #include "isp1760-hcd.h"
+#include "isp1760-udc.h"
 
 struct device;
 struct gpio_desc;
···
 	struct gpio_desc *rst_gpio;
 
 	struct isp1760_hcd hcd;
+	struct isp1760_udc udc;
 };
 
 int isp1760_register(struct resource *mem, int irq, unsigned long irqflags,
 		     struct device *dev, unsigned int devflags);
 void isp1760_unregister(struct device *dev);
+
+void isp1760_set_pullup(struct isp1760_device *isp, bool enable);
 
 static inline u32 isp1760_read32(void __iomem *base, u32 reg)
 {

drivers/usb/host/isp1760-regs.h

···
 #ifndef _ISP1760_REGS_H_
 #define _ISP1760_REGS_H_
 
+/* -----------------------------------------------------------------------------
+ * Host Controller
+ */
+
 /* EHCI capability registers */
 #define HC_CAPLENGTH		0x000
 #define HC_LENGTH(p)		(((p) >> 00) & 0x00ff)	/* bits 7:0 */
···
 #define HC_HW_MODE_CTRL		0x300
 #define ALL_ATX_RESET		(1 << 31)
 #define HW_ANA_DIGI_OC		(1 << 15)
+#define HW_DEV_DMA		(1 << 11)
+#define HW_COMN_IRQ		(1 << 10)
+#define HW_COMN_DMA		(1 << 9)
 #define HW_DATA_BUS_32BIT	(1 << 8)
 #define HW_DACK_POL_HIGH	(1 << 6)
 #define HW_DREQ_POL_HIGH	(1 << 5)
···
 #define PORT1_INIT2		(1 << 23)
 #define HW_OTG_CTRL_SET		0x374
 #define HW_OTG_CTRL_CLR		0x376
+#define HW_OTG_DISABLE		(1 << 10)
+#define HW_OTG_SE0_EN		(1 << 9)
+#define HW_BDIS_ACON_EN		(1 << 8)
+#define HW_SW_SEL_HC_DC		(1 << 7)
+#define HW_VBUS_CHRG		(1 << 6)
+#define HW_VBUS_DISCHRG		(1 << 5)
+#define HW_VBUS_DRV		(1 << 4)
+#define HW_SEL_CP_EXT		(1 << 3)
+#define HW_DM_PULLDOWN		(1 << 2)
+#define HW_DP_PULLDOWN		(1 << 1)
+#define HW_DP_PULLUP		(1 << 0)
 
 /* Interrupt Register */
 #define HC_INTERRUPT_REG	0x310
···
 #define HC_ISO_IRQ_MASK_AND_REG	0x324
 #define HC_INT_IRQ_MASK_AND_REG	0x328
 #define HC_ATL_IRQ_MASK_AND_REG	0x32c
+
+/* -----------------------------------------------------------------------------
+ * Peripheral Controller
+ */
+
+/* Initialization Registers */
+#define DC_ADDRESS			0x0200
+#define DC_DEVEN			(1 << 7)
+
+#define DC_MODE				0x020c
+#define DC_DMACLKON			(1 << 9)
+#define DC_VBUSSTAT			(1 << 8)
+#define DC_CLKAON			(1 << 7)
+#define DC_SNDRSU			(1 << 6)
+#define DC_GOSUSP			(1 << 5)
+#define DC_SFRESET			(1 << 4)
+#define DC_GLINTENA			(1 << 3)
+#define DC_WKUPCS			(1 << 2)
+
+#define DC_INTCONF			0x0210
+#define DC_CDBGMOD_ACK_NAK		(0 << 6)
+#define DC_CDBGMOD_ACK			(1 << 6)
+#define DC_CDBGMOD_ACK_1NAK		(2 << 6)
+#define DC_DDBGMODIN_ACK_NAK		(0 << 4)
+#define DC_DDBGMODIN_ACK		(1 << 4)
+#define DC_DDBGMODIN_ACK_1NAK		(2 << 4)
+#define DC_DDBGMODOUT_ACK_NYET_NAK	(0 << 2)
+#define DC_DDBGMODOUT_ACK_NYET		(1 << 2)
+#define DC_DDBGMODOUT_ACK_NYET_1NAK	(2 << 2)
+#define DC_INTLVL			(1 << 1)
+#define DC_INTPOL			(1 << 0)
+
+#define DC_DEBUG			0x0212
+#define DC_INTENABLE			0x0214
+#define DC_IEPTX(n)			(1 << (11 + 2 * (n)))
+#define DC_IEPRX(n)			(1 << (10 + 2 * (n)))
+#define DC_IEPRXTX(n)			(3 << (10 + 2 * (n)))
+#define DC_IEP0SETUP			(1 << 8)
+#define DC_IEVBUS			(1 << 7)
+#define DC_IEDMA			(1 << 6)
+#define DC_IEHS_STA			(1 << 5)
+#define DC_IERESM			(1 << 4)
+#define DC_IESUSP			(1 << 3)
+#define DC_IEPSOF			(1 << 2)
+#define DC_IESOF			(1 << 1)
+#define DC_IEBRST			(1 << 0)
+
+/* Data Flow Registers */
+#define DC_EPINDEX			0x022c
+#define DC_EP0SETUP			(1 << 5)
+#define DC_ENDPIDX(n)			((n) << 1)
+#define DC_EPDIR			(1 << 0)
+
+#define DC_CTRLFUNC			0x0228
+#define DC_CLBUF			(1 << 4)
+#define DC_VENDP			(1 << 3)
+#define DC_DSEN				(1 << 2)
+#define DC_STATUS			(1 << 1)
+#define DC_STALL			(1 << 0)
+
+#define DC_DATAPORT			0x0220
+#define DC_BUFLEN			0x021c
+#define DC_DATACOUNT_MASK		0xffff
+#define DC_BUFSTAT			0x021e
+#define DC_EPMAXPKTSZ			0x0204
+
+#define DC_EPTYPE			0x0208
+#define DC_NOEMPKT			(1 << 4)
+#define DC_EPENABLE			(1 << 3)
+#define DC_DBLBUF			(1 << 2)
+#define DC_ENDPTYP_ISOC			(1 << 0)
+#define DC_ENDPTYP_BULK			(2 << 0)
+#define DC_ENDPTYP_INTERRUPT		(3 << 0)
+
+/* DMA Registers */
+#define DC_DMACMD			0x0230
+#define DC_DMATXCOUNT			0x0234
+#define DC_DMACONF			0x0238
+#define DC_DMAHW			0x023c
+#define DC_DMAINTREASON			0x0250
+#define DC_DMAINTEN			0x0254
+#define DC_DMAEP			0x0258
+#define DC_DMABURSTCOUNT		0x0264
+
+/* General Registers */
+#define DC_INTERRUPT			0x0218
+#define DC_CHIPID			0x0270
+#define DC_FRAMENUM			0x0274
+#define DC_SCRATCH			0x0278
+#define DC_UNLOCKDEV			0x027c
+#define DC_INTPULSEWIDTH		0x0280
+#define DC_TESTMODE			0x0284
 
 #endif

drivers/usb/host/isp1760-udc.c

···
+/*
+ * Driver for the NXP ISP1761 device controller
+ *
+ * Copyright 2014 Ideas on Board Oy
+ *
+ * Contacts:
+ *	Laurent Pinchart <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include <linux/usb.h>
+
+#include "isp1760-core.h"
+#include "isp1760-regs.h"
+#include "isp1760-udc.h"
+
+#define ISP1760_VBUS_POLL_INTERVAL	msecs_to_jiffies(500)
+
+struct isp1760_request {
+	struct usb_request req;
+	struct list_head queue;
+	struct isp1760_ep *ep;
+	unsigned int packet_size;
+};
+
+static inline struct isp1760_udc *gadget_to_udc(struct usb_gadget *gadget)
+{
+	return container_of(gadget, struct isp1760_udc, gadget);
+}
+
+static inline struct isp1760_ep *ep_to_udc_ep(struct usb_ep *ep)
+{
+	return container_of(ep, struct isp1760_ep, ep);
+}
+
+static inline struct isp1760_request *req_to_udc_req(struct usb_request *req)
+{
+	return container_of(req, struct isp1760_request, req);
+}
+
+static inline u32 isp1760_udc_read(struct isp1760_udc *udc, u16 reg)
+{
+	return isp1760_read32(udc->regs, reg);
+}
+
+static inline void isp1760_udc_write(struct isp1760_udc *udc, u16 reg, u32 val)
+{
+	isp1760_write32(udc->regs, reg, val);
+}
+
+/* -----------------------------------------------------------------------------
+ * Endpoint Management
+ */
+
+static struct isp1760_ep *isp1760_udc_find_ep(struct isp1760_udc *udc,
+					      u16 index)
+{
+	unsigned int i;
+
+	if (index == 0)
+		return &udc->ep[0];
+
+	for (i = 1; i < ARRAY_SIZE(udc->ep); ++i) {
+		if (udc->ep[i].addr == index)
+			return udc->ep[i].desc ? &udc->ep[i] : NULL;
+	}
+
+	return NULL;
+}
+
+static void __isp1760_udc_select_ep(struct isp1760_ep *ep, int dir)
+{
+	isp1760_udc_write(ep->udc, DC_EPINDEX,
+			  DC_ENDPIDX(ep->addr & USB_ENDPOINT_NUMBER_MASK) |
+			  (dir == USB_DIR_IN ? DC_EPDIR : 0));
+}
+
+/**
+ * isp1760_udc_select_ep - Select an endpoint for register access
+ * @ep: The endpoint
+ *
+ * The ISP1761 endpoint registers are banked. This function selects the target
+ * endpoint for banked register access. The selection remains valid until the
+ * next call to this function, the next direct access to the EPINDEX register
+ * or the next reset, whichever comes first.
+ *
+ * Called with the UDC spinlock held.
+ */
+static void isp1760_udc_select_ep(struct isp1760_ep *ep)
+{
+	__isp1760_udc_select_ep(ep, ep->addr & USB_ENDPOINT_DIR_MASK);
+}
+
+/* Called with the UDC spinlock held. */
+static void isp1760_udc_ctrl_send_status(struct isp1760_ep *ep, int dir)
+{
+	struct isp1760_udc *udc = ep->udc;
+
+	/*
+	 * Proceed to the status stage. The status stage data packet flows in
+	 * the direction opposite to the data stage data packets, we thus need
+	 * to select the OUT/IN endpoint for IN/OUT transfers.
+	 */
+	isp1760_udc_write(udc, DC_EPINDEX, DC_ENDPIDX(0) |
+			  (dir == USB_DIR_IN ? 0 : DC_EPDIR));
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_STATUS);
+
+	/*
+	 * The hardware will terminate the request automatically and go back to
+	 * the setup stage without notifying us.
+	 */
+	udc->ep0_state = ISP1760_CTRL_SETUP;
+}
+
+/* Called without the UDC spinlock held. */
+static void isp1760_udc_request_complete(struct isp1760_ep *ep,
+					 struct isp1760_request *req,
+					 int status)
+{
+	struct isp1760_udc *udc = ep->udc;
+	unsigned long flags;
+
+	dev_dbg(ep->udc->isp->dev, "completing request %p with status %d\n",
+		req, status);
+
+	req->ep = NULL;
+	req->req.status = status;
+	req->req.complete(&ep->ep, &req->req);
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/*
+	 * When completing control OUT requests, move to the status stage after
+	 * calling the request complete callback. This gives the gadget an
+	 * opportunity to stall the control transfer if needed.
+	 */
+	if (status == 0 && ep->addr == 0 && udc->ep0_dir == USB_DIR_OUT)
+		isp1760_udc_ctrl_send_status(ep, USB_DIR_OUT);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
+static void isp1760_udc_ctrl_send_stall(struct isp1760_ep *ep)
+{
+	struct isp1760_udc *udc = ep->udc;
+	unsigned long flags;
+
+	dev_dbg(ep->udc->isp->dev, "%s(ep%02x)\n", __func__, ep->addr);
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/* Stall both the IN and OUT endpoints. */
+	__isp1760_udc_select_ep(ep, USB_DIR_OUT);
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_STALL);
+	__isp1760_udc_select_ep(ep, USB_DIR_IN);
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_STALL);
+
+	/* A protocol stall completes the control transaction. */
+	udc->ep0_state = ISP1760_CTRL_SETUP;
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
+/* -----------------------------------------------------------------------------
+ * Data Endpoints
+ */
+
+/* Called with the UDC spinlock held. */
+static bool isp1760_udc_receive(struct isp1760_ep *ep,
+				struct isp1760_request *req)
+{
+	struct isp1760_udc *udc = ep->udc;
+	unsigned int len;
+	u32 *buf;
+	int i;
+
+	isp1760_udc_select_ep(ep);
+	len = isp1760_udc_read(udc, DC_BUFLEN) & DC_DATACOUNT_MASK;
+
+	dev_dbg(udc->isp->dev, "%s: received %u bytes (%u/%u done)\n",
+		__func__, len, req->req.actual, req->req.length);
+
+	len = min(len, req->req.length - req->req.actual);
+
+	if (!len) {
+		/*
+		 * There's no data to be read from the FIFO, acknowledge the RX
+		 * interrupt by clearing the buffer.
+		 *
+		 * TODO: What if another packet arrives in the meantime ? The
+		 * datasheet doesn't clearly document how this should be
+		 * handled.
+		 */
+		isp1760_udc_write(udc, DC_CTRLFUNC, DC_CLBUF);
+		return false;
+	}
+
+	buf = req->req.buf + req->req.actual;
+
+	/*
+	 * Make sure not to read more than one extra byte, otherwise data from
+	 * the next packet might be removed from the FIFO.
+	 */
+	for (i = len; i > 2; i -= 4, ++buf)
+		*buf = le32_to_cpu(isp1760_udc_read(udc, DC_DATAPORT));
+	if (i > 0)
+		*(u16 *)buf = le16_to_cpu(readw(udc->regs + DC_DATAPORT));
+
+	req->req.actual += len;
+
+	/*
+	 * TODO: The short_not_ok flag isn't supported yet, but isn't used by
+	 * any gadget driver either.
+	 */
+
+	dev_dbg(udc->isp->dev,
+		"%s: req %p actual/length %u/%u maxpacket %u packet size %u\n",
+		__func__, req, req->req.actual, req->req.length, ep->maxpacket,
+		len);
+
+	ep->rx_pending = false;
+
+	/*
+	 * Complete the request if all data has been received or if a short
+	 * packet has been received.
+	 */
+	if (req->req.actual == req->req.length || len < ep->maxpacket) {
+		list_del(&req->queue);
+		return true;
+	}
+
+	return false;
+}
+
+static void isp1760_udc_transmit(struct isp1760_ep *ep,
+				 struct isp1760_request *req)
+{
+	struct isp1760_udc *udc = ep->udc;
+	u32 *buf = req->req.buf + req->req.actual;
+	int i;
+
+	req->packet_size = min(req->req.length - req->req.actual,
+			       ep->maxpacket);
+
+	dev_dbg(udc->isp->dev, "%s: transferring %u bytes (%u/%u done)\n",
+		__func__, req->packet_size, req->req.actual,
+		req->req.length);
+
+	__isp1760_udc_select_ep(ep, USB_DIR_IN);
+
+	if (req->packet_size)
+		isp1760_udc_write(udc, DC_BUFLEN, req->packet_size);
+
+	/*
+	 * Make sure not to write more than one extra byte, otherwise extra data
+	 * will stay in the FIFO and will be transmitted during the next control
+	 * request. The endpoint control CLBUF bit is supposed to allow flushing
+	 * the FIFO for this kind of conditions, but doesn't seem to work.
+	 */
+	for (i = req->packet_size; i > 2; i -= 4, ++buf)
+		isp1760_udc_write(udc, DC_DATAPORT, cpu_to_le32(*buf));
+	if (i > 0)
+		writew(cpu_to_le16(*(u16 *)buf), udc->regs + DC_DATAPORT);
+
+	if (ep->addr == 0)
+		isp1760_udc_write(udc, DC_CTRLFUNC, DC_DSEN);
+	if (!req->packet_size)
+		isp1760_udc_write(udc, DC_CTRLFUNC, DC_VENDP);
+}
+
+static void isp1760_ep_rx_ready(struct isp1760_ep *ep)
+{
+	struct isp1760_udc *udc = ep->udc;
+	struct isp1760_request *req;
+	bool complete;
+
+	spin_lock(&udc->lock);
+
+	if (ep->addr == 0 && udc->ep0_state != ISP1760_CTRL_DATA_OUT) {
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "%s: invalid ep0 state %u\n", __func__,
+			udc->ep0_state);
+		return;
+	}
+
+	if (ep->addr != 0 && !ep->desc) {
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "%s: ep%02x is disabled\n", __func__,
+			ep->addr);
+		return;
+	}
+
+	if (list_empty(&ep->queue)) {
+		ep->rx_pending = true;
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "%s: ep%02x (%p) has no request queued\n",
+			__func__, ep->addr, ep);
+		return;
+	}
+
+	req = list_first_entry(&ep->queue, struct isp1760_request,
+			       queue);
+	complete = isp1760_udc_receive(ep, req);
+
+	spin_unlock(&udc->lock);
+
+	if (complete)
+		isp1760_udc_request_complete(ep, req, 0);
+}
+
+static void isp1760_ep_tx_complete(struct isp1760_ep *ep)
+{
+	struct isp1760_udc *udc = ep->udc;
+	struct isp1760_request *complete = NULL;
+	struct isp1760_request *req;
+	bool need_zlp;
+
+	spin_lock(&udc->lock);
+
+	if (ep->addr == 0 && udc->ep0_state != ISP1760_CTRL_DATA_IN) {
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "TX IRQ: invalid endpoint state %u\n",
+			udc->ep0_state);
+		return;
+	}
+
+	if (list_empty(&ep->queue)) {
+		/*
+		 * This can happen for the control endpoint when the reply to
+		 * the GET_STATUS IN control request is sent directly by the
+		 * setup IRQ handler. Just proceed to the status stage.
+		 */
+		if (ep->addr == 0) {
+			isp1760_udc_ctrl_send_status(ep, USB_DIR_IN);
+			spin_unlock(&udc->lock);
+			return;
+		}
+
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "%s: ep%02x has no request queued\n",
+			__func__, ep->addr);
+		return;
+	}
+
+	req = list_first_entry(&ep->queue, struct isp1760_request,
+			       queue);
+	req->req.actual += req->packet_size;
+
+	need_zlp = req->req.actual == req->req.length &&
+		   !(req->req.length % ep->maxpacket) &&
+		   req->packet_size && req->req.zero;
+
+	dev_dbg(udc->isp->dev,
+		"TX IRQ: req %p actual/length %u/%u maxpacket %u packet size %u zero %u need zlp %u\n",
+		 req, req->req.actual, req->req.length, ep->maxpacket,
+		 req->packet_size, req->req.zero, need_zlp);
+
+	/*
+	 * Complete the request if all data has been sent and we don't need to
+	 * transmit a zero length packet.
+	 */
+	if (req->req.actual == req->req.length && !need_zlp) {
+		complete = req;
+		list_del(&req->queue);
+
+		if (ep->addr == 0)
+			isp1760_udc_ctrl_send_status(ep, USB_DIR_IN);
+
+		if (!list_empty(&ep->queue))
+			req = list_first_entry(&ep->queue,
+					       struct isp1760_request, queue);
+		else
+			req = NULL;
+	}
+
+	/*
+	 * Transmit the next packet or start the next request, if any.
+	 *
+	 * TODO: If the endpoint is stalled the next request shouldn't be
+	 * started, but what about the next packet ?
+	 */
+	if (req)
+		isp1760_udc_transmit(ep, req);
+
+	spin_unlock(&udc->lock);
+
+	if (complete)
+		isp1760_udc_request_complete(ep, complete, 0);
+}
+
+static int __isp1760_udc_set_halt(struct isp1760_ep *ep, bool halt)
+{
+	struct isp1760_udc *udc = ep->udc;
+
+	dev_dbg(udc->isp->dev, "%s: %s halt on ep%02x\n", __func__,
+		halt ? "set" : "clear", ep->addr);
+
+	if (ep->desc && usb_endpoint_xfer_isoc(ep->desc)) {
+		dev_dbg(udc->isp->dev, "%s: ep%02x is isochronous\n", __func__,
+			ep->addr);
+		return -EINVAL;
+	}
+
+	isp1760_udc_select_ep(ep);
+	isp1760_udc_write(udc, DC_CTRLFUNC, halt ? DC_STALL : 0);
+
+	if (ep->addr == 0) {
+		/* When halting the control endpoint, stall both IN and OUT. */
+		__isp1760_udc_select_ep(ep, USB_DIR_IN);
+		isp1760_udc_write(udc, DC_CTRLFUNC, halt ? DC_STALL : 0);
+	} else if (!halt) {
+		/* Reset the data PID by cycling the endpoint enable bit. */
+		u16 eptype = isp1760_udc_read(udc, DC_EPTYPE);
+
+		isp1760_udc_write(udc, DC_EPTYPE, eptype & ~DC_EPENABLE);
+		isp1760_udc_write(udc, DC_EPTYPE, eptype);
+
+		/*
+		 * Disabling the endpoint emptied the transmit FIFO, fill it
+		 * again if a request is pending.
+		 *
+		 * TODO: Does the gadget framework require synchronizatino with
+		 * the TX IRQ handler ?
+		 */
+		if ((ep->addr & USB_DIR_IN) && !list_empty(&ep->queue)) {
+			struct isp1760_request *req;
+
+			req = list_first_entry(&ep->queue,
+					       struct isp1760_request, queue);
+			isp1760_udc_transmit(ep, req);
+		}
+	}
+
+	ep->halted = halt;
+
+	return 0;
+}
+
+/* -----------------------------------------------------------------------------
+ * Control Endpoint
+ */
+
+static int isp1760_udc_get_status(struct isp1760_udc *udc,
+				  const struct usb_ctrlrequest *req)
+{
+	struct isp1760_ep *ep;
+	u16 status;
+
+	if (req->wLength != cpu_to_le16(2) || req->wValue != cpu_to_le16(0))
+		return -EINVAL;
+
+	switch (req->bRequestType) {
+	case USB_DIR_IN | USB_RECIP_DEVICE:
+		status = udc->devstatus;
+		break;
+
+	case USB_DIR_IN | USB_RECIP_INTERFACE:
+		status = 0;
+		break;
+
+	case USB_DIR_IN | USB_RECIP_ENDPOINT:
+		ep = isp1760_udc_find_ep(udc, le16_to_cpu(req->wIndex));
+		if (!ep)
+			return -EINVAL;
+
+		status = 0;
+		if (ep->halted)
+			status |= 1 << USB_ENDPOINT_HALT;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	isp1760_udc_write(udc, DC_EPINDEX, DC_ENDPIDX(0) | DC_EPDIR);
+	isp1760_udc_write(udc, DC_BUFLEN, 2);
+
+	writew(cpu_to_le16(status), udc->regs + DC_DATAPORT);
+
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_DSEN);
+
+	dev_dbg(udc->isp->dev, "%s: status 0x%04x\n", __func__, status);
+
+	return 0;
+}
+
+static int isp1760_udc_set_address(struct isp1760_udc *udc, u16 addr)
+{
+	if (addr > 127) {
+		dev_dbg(udc->isp->dev, "invalid device address %u\n", addr);
+		return -EINVAL;
+	}
+
+	if (udc->gadget.state != USB_STATE_DEFAULT &&
+	    udc->gadget.state != USB_STATE_ADDRESS) {
+		dev_dbg(udc->isp->dev, "can't set address in state %u\n",
+			udc->gadget.state);
+		return -EINVAL;
+	}
+
+	usb_gadget_set_state(&udc->gadget, addr ? USB_STATE_ADDRESS :
+			     USB_STATE_DEFAULT);
+
+	isp1760_udc_write(udc, DC_ADDRESS, DC_DEVEN | addr);
+
+	spin_lock(&udc->lock);
+	isp1760_udc_ctrl_send_status(&udc->ep[0], USB_DIR_OUT);
+	spin_unlock(&udc->lock);
+
+	return 0;
+}
+
+static bool isp1760_ep0_setup_standard(struct isp1760_udc *udc,
+				       struct usb_ctrlrequest *req)
+{
+	bool stall;
+
+	switch (req->bRequest) {
+	case USB_REQ_GET_STATUS:
+		return isp1760_udc_get_status(udc, req);
+
+	case USB_REQ_CLEAR_FEATURE:
+		switch (req->bRequestType) {
+		case USB_DIR_OUT | USB_RECIP_DEVICE: {
+			/* TODO: Handle remote wakeup feature. */
+			return true;
+		}
+
+		case USB_DIR_OUT | USB_RECIP_ENDPOINT: {
+			u16 index = le16_to_cpu(req->wIndex);
+			struct isp1760_ep *ep;
+
+			if (req->wLength != cpu_to_le16(0) ||
+			    req->wValue != cpu_to_le16(USB_ENDPOINT_HALT))
+				return true;
+
+			ep = isp1760_udc_find_ep(udc, index);
+			if (!ep)
+				return true;
+
+			spin_lock(&udc->lock);
+
+			/*
+			 * If the endpoint is wedged only the gadget can clear
+			 * the halt feature. Pretend success in that case, but
+			 * keep the endpoint halted.
+			 */
+			if (!ep->wedged)
+				stall = __isp1760_udc_set_halt(ep, false);
+			else
+				stall = false;
+
+			if (!stall)
+				isp1760_udc_ctrl_send_status(&udc->ep[0],
+							     USB_DIR_OUT);
+
+			spin_unlock(&udc->lock);
+			return stall;
+		}
+
+		default:
+			return true;
+		}
+		break;
+
+	case USB_REQ_SET_FEATURE:
+		switch (req->bRequestType) {
+		case USB_DIR_OUT | USB_RECIP_DEVICE: {
+			/* TODO: Handle remote wakeup and test mode features */
+			return true;
+		}
+
+		case USB_DIR_OUT | USB_RECIP_ENDPOINT: {
+			u16 index = le16_to_cpu(req->wIndex);
+			struct isp1760_ep *ep;
+
+			if (req->wLength != cpu_to_le16(0) ||
+			    req->wValue != cpu_to_le16(USB_ENDPOINT_HALT))
+				return true;
+
+			ep = isp1760_udc_find_ep(udc, index);
+			if (!ep)
+				return true;
+
+			spin_lock(&udc->lock);
+
+			stall = __isp1760_udc_set_halt(ep, true);
+			if (!stall)
+				isp1760_udc_ctrl_send_status(&udc->ep[0],
+							     USB_DIR_OUT);
+
+			spin_unlock(&udc->lock);
+			return stall;
+		}
+
+		default:
+			return true;
+		}
+		break;
+
+	case USB_REQ_SET_ADDRESS:
+		if (req->bRequestType != (USB_DIR_OUT | USB_RECIP_DEVICE))
+			return true;
+
+		return isp1760_udc_set_address(udc, le16_to_cpu(req->wValue));
+
+	case USB_REQ_SET_CONFIGURATION:
+		if (req->bRequestType != (USB_DIR_OUT | USB_RECIP_DEVICE))
+			return true;
+
+		if (udc->gadget.state != USB_STATE_ADDRESS &&
+		    udc->gadget.state != USB_STATE_CONFIGURED)
+			return true;
+
+		stall = udc->driver->setup(&udc->gadget, req) < 0;
+		if (stall)
+			return true;
+
+		usb_gadget_set_state(&udc->gadget, req->wValue ?
+				     USB_STATE_CONFIGURED : USB_STATE_ADDRESS);
+
+		/*
+		 * SET_CONFIGURATION (and SET_INTERFACE) must reset the halt
+		 * feature on all endpoints. There is however no need to do so
+		 * explicitly here as the gadget driver will disable and
+		 * reenable endpoints, clearing the halt feature.
+		 */
+		return false;
+
+	default:
+		return udc->driver->setup(&udc->gadget, req) < 0;
+	}
+}
+
+static void isp1760_ep0_setup(struct isp1760_udc *udc)
+{
+	union {
+		struct usb_ctrlrequest r;
+		u32 data[2];
+	} req;
+	unsigned int count;
+	bool stall = false;
+
+	spin_lock(&udc->lock);
+
+	isp1760_udc_write(udc, DC_EPINDEX, DC_EP0SETUP);
+
+	count = isp1760_udc_read(udc, DC_BUFLEN) & DC_DATACOUNT_MASK;
+	if (count != sizeof(req)) {
+		spin_unlock(&udc->lock);
+
+		dev_err(udc->isp->dev, "invalid length %u for setup packet\n",
+			count);
+
+		isp1760_udc_ctrl_send_stall(&udc->ep[0]);
+		return;
+	}
+
+	req.data[0] = isp1760_udc_read(udc, DC_DATAPORT);
+	req.data[1] = isp1760_udc_read(udc, DC_DATAPORT);
+
+	if (udc->ep0_state != ISP1760_CTRL_SETUP) {
+		spin_unlock(&udc->lock);
+		dev_dbg(udc->isp->dev, "unexpected SETUP packet\n");
+		return;
+	}
+
+	/* Move to the data stage. */
+	if (!req.r.wLength)
+		udc->ep0_state = ISP1760_CTRL_STATUS;
+	else if (req.r.bRequestType & USB_DIR_IN)
+		udc->ep0_state = ISP1760_CTRL_DATA_IN;
+	else
+		udc->ep0_state = ISP1760_CTRL_DATA_OUT;
+
+	udc->ep0_dir = req.r.bRequestType & USB_DIR_IN;
+	udc->ep0_length = le16_to_cpu(req.r.wLength);
+
+	spin_unlock(&udc->lock);
+
+	dev_dbg(udc->isp->dev,
+		"%s: bRequestType 0x%02x bRequest 0x%02x wValue 0x%04x wIndex 0x%04x wLength 0x%04x\n",
+		__func__, req.r.bRequestType, req.r.bRequest,
+		le16_to_cpu(req.r.wValue), le16_to_cpu(req.r.wIndex),
+		le16_to_cpu(req.r.wLength));
+
+	if ((req.r.bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
+		stall = isp1760_ep0_setup_standard(udc, &req.r);
+	else
+		stall = udc->driver->setup(&udc->gadget, &req.r) < 0;
+
+	if (stall)
+		isp1760_udc_ctrl_send_stall(&udc->ep[0]);
+}
+
+/* -----------------------------------------------------------------------------
+ * Gadget Endpoint Operations
+ */
+
+static int isp1760_ep_enable(struct usb_ep *ep,
+			     const struct usb_endpoint_descriptor *desc)
+{
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	struct isp1760_udc *udc = uep->udc;
+	unsigned long flags;
+	unsigned int type;
+
+	dev_dbg(uep->udc->isp->dev, "%s\n", __func__);
+
+	/*
+	 * Validate the descriptor. The control endpoint can't be enabled
+	 * manually.
+	 */
+	if (desc->bDescriptorType != USB_DT_ENDPOINT ||
+	    desc->bEndpointAddress == 0 ||
+	    desc->bEndpointAddress != uep->addr ||
+	    le16_to_cpu(desc->wMaxPacketSize) > ep->maxpacket) {
+		dev_dbg(udc->isp->dev,
+			"%s: invalid descriptor type %u addr %02x ep addr %02x max packet size %u/%u\n",
+			__func__, desc->bDescriptorType,
+			desc->bEndpointAddress, uep->addr,
+			le16_to_cpu(desc->wMaxPacketSize), ep->maxpacket);
+		return -EINVAL;
+	}
+
+	switch (usb_endpoint_type(desc)) {
+	case USB_ENDPOINT_XFER_ISOC:
+		type = DC_ENDPTYP_ISOC;
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		type = DC_ENDPTYP_BULK;
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		type = DC_ENDPTYP_INTERRUPT;
+		break;
+	case USB_ENDPOINT_XFER_CONTROL:
+	default:
+		dev_dbg(udc->isp->dev, "%s: control endpoints unsupported\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	uep->desc = desc;
+	uep->maxpacket = le16_to_cpu(desc->wMaxPacketSize);
+	uep->rx_pending = false;
+	uep->halted = false;
+	uep->wedged = false;
+
+	isp1760_udc_select_ep(uep);
+	isp1760_udc_write(udc, DC_EPMAXPKTSZ, uep->maxpacket);
+	isp1760_udc_write(udc, DC_BUFLEN, uep->maxpacket);
+	isp1760_udc_write(udc, DC_EPTYPE, DC_EPENABLE | type);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	return 0;
+}
+
+static int isp1760_ep_disable(struct usb_ep *ep)
+{
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	struct isp1760_udc *udc = uep->udc;
+	struct isp1760_request *req, *nreq;
+	LIST_HEAD(req_list);
+	unsigned long flags;
+
+	dev_dbg(udc->isp->dev, "%s\n", __func__);
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	if (!uep->desc) {
+		dev_dbg(udc->isp->dev, "%s: endpoint not enabled\n", __func__);
+		spin_unlock_irqrestore(&udc->lock, flags);
+		return -EINVAL;
+	}
+
+	uep->desc = NULL;
+	uep->maxpacket = 0;
+
+	isp1760_udc_select_ep(uep);
+	isp1760_udc_write(udc, DC_EPTYPE, 0);
+
+	/* TODO Synchronize with the IRQ handler */
+
+	list_splice_init(&uep->queue, &req_list);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	list_for_each_entry_safe(req, nreq, &req_list, queue) {
+		list_del(&req->queue);
+		isp1760_udc_request_complete(uep, req, -ESHUTDOWN);
+	}
+
+	return 0;
+}
+
+static struct usb_request *isp1760_ep_alloc_request(struct usb_ep *ep,
+						    gfp_t gfp_flags)
+{
+	struct isp1760_request *req;
+
+	req = kzalloc(sizeof(*req), gfp_flags);
+
+	return &req->req;
+}
+
+static void isp1760_ep_free_request(struct usb_ep *ep, struct usb_request *_req)
+{
+	struct isp1760_request *req = req_to_udc_req(_req);
+
+	kfree(req);
+}
+
+static int isp1760_ep_queue(struct usb_ep *ep, struct usb_request *_req,
+			    gfp_t gfp_flags)
+{
+	struct isp1760_request *req = req_to_udc_req(_req);
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	struct isp1760_udc *udc = uep->udc;
+	bool complete = false;
+	unsigned long flags;
+	int ret = 0;
+
+	_req->status = -EINPROGRESS;
+	_req->actual = 0;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	dev_dbg(udc->isp->dev,
+		"%s: req %p (%u bytes%s) ep %p(0x%02x)\n", __func__, _req,
+		_req->length, _req->zero ? " (zlp)" : "", uep, uep->addr);
+
+	req->ep = uep;
+
+	if (uep->addr == 0) {
+		if (_req->length != udc->ep0_length &&
+		    udc->ep0_state != ISP1760_CTRL_DATA_IN) {
+			dev_dbg(udc->isp->dev,
+				"%s: invalid length %u for req %p\n",
+				__func__, _req->length, req);
+			ret = -EINVAL;
+			goto done;
+		}
+
+		switch (udc->ep0_state) {
+		case ISP1760_CTRL_DATA_IN:
+			dev_dbg(udc->isp->dev, "%s: transmitting req %p\n",
+				__func__, req);
+
+			list_add_tail(&req->queue, &uep->queue);
+			isp1760_udc_transmit(uep, req);
+			break;
+
+		case ISP1760_CTRL_DATA_OUT:
+			list_add_tail(&req->queue, &uep->queue);
+			__isp1760_udc_select_ep(uep, USB_DIR_OUT);
+			isp1760_udc_write(udc, DC_CTRLFUNC, DC_DSEN);
+			break;
+
+		case ISP1760_CTRL_STATUS:
+			complete = true;
+			break;
+
+		default:
+			dev_dbg(udc->isp->dev, "%s: invalid ep0 state\n",
+				__func__);
+			ret = -EINVAL;
+			break;
+		}
+	} else if (uep->desc) {
+		bool empty = list_empty(&uep->queue);
+
+		list_add_tail(&req->queue, &uep->queue);
+		if ((uep->addr & USB_DIR_IN) && !uep->halted && empty)
+			isp1760_udc_transmit(uep, req);
+		else if (!(uep->addr & USB_DIR_IN) && uep->rx_pending)
+			complete = isp1760_udc_receive(uep, req);
+	} else {
+		dev_dbg(udc->isp->dev,
+			"%s: can't queue request to disabled ep%02x\n",
+			__func__, uep->addr);
+		ret = -ESHUTDOWN;
+	}
+
+done:
+	if (ret < 0)
+		req->ep = NULL;
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	if (complete)
+		isp1760_udc_request_complete(uep, req, 0);
+
+	return ret;
+}
+
+static int isp1760_ep_dequeue(struct usb_ep *ep, struct usb_request *_req)
+{
+	struct isp1760_request *req = req_to_udc_req(_req);
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	struct isp1760_udc *udc = uep->udc;
+	unsigned long flags;
+
+	dev_dbg(uep->udc->isp->dev, "%s(ep%02x)\n", __func__, uep->addr);
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	if (req->ep != uep)
+		req = NULL;
+	else
+		list_del(&req->queue);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+
+	if (!req)
+		return -EINVAL;
+
+	isp1760_udc_request_complete(uep, req, -ECONNRESET);
+	return 0;
+}
+
+static int __isp1760_ep_set_halt(struct isp1760_ep *uep, bool stall, bool wedge)
+{
+	struct isp1760_udc *udc = uep->udc;
+	int ret;
+
+	if (!uep->addr) {
+		/*
+		 * Halting the control endpoint is only valid as a delayed error
+		 * response to a SETUP packet. Make sure EP0 is in the right
+		 * stage and that the gadget isn't trying to clear the halt
+		 * condition.
+		 */
+		if (WARN_ON(udc->ep0_state == ISP1760_CTRL_SETUP || !stall ||
+			     wedge)) {
+			return -EINVAL;
+		}
+	}
+
+	if (uep->addr && !uep->desc) {
+		dev_dbg(udc->isp->dev, "%s: ep%02x is disabled\n", __func__,
+			uep->addr);
+		return -EINVAL;
+	}
+
+	if (uep->addr & USB_DIR_IN) {
+		/* Refuse to halt IN endpoints with active transfers. */
+		if (!list_empty(&uep->queue)) {
+			dev_dbg(udc->isp->dev,
+				"%s: ep%02x has request pending\n", __func__,
+				uep->addr);
+			return -EAGAIN;
+		}
+	}
+
+	ret = __isp1760_udc_set_halt(uep, stall);
+	if (ret < 0)
+		return ret;
+
+	if (!uep->addr) {
+		/*
+		 * Stalling EP0 completes the control transaction, move back to
+		 * the SETUP state.
+		 */
+		udc->ep0_state = ISP1760_CTRL_SETUP;
+		return 0;
+	}
+
+	if (wedge)
+		uep->wedged = true;
+	else if (!stall)
+		uep->wedged = false;
+
+	return 0;
+}
+
+static int isp1760_ep_set_halt(struct usb_ep *ep, int value)
+{
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	unsigned long flags;
+	int ret;
+
+	dev_dbg(uep->udc->isp->dev, "%s: %s halt on ep%02x\n", __func__,
+		value ? "set" : "clear", uep->addr);
+
+	spin_lock_irqsave(&uep->udc->lock, flags);
+	ret = __isp1760_ep_set_halt(uep, value, false);
+	spin_unlock_irqrestore(&uep->udc->lock, flags);
+
+	return ret;
+}
+
+static int isp1760_ep_set_wedge(struct usb_ep *ep)
+{
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	unsigned long flags;
+	int ret;
+
+	dev_dbg(uep->udc->isp->dev, "%s: set wedge on ep%02x)\n", __func__,
+		uep->addr);
+
+	spin_lock_irqsave(&uep->udc->lock, flags);
+	ret = __isp1760_ep_set_halt(uep, true, true);
+	spin_unlock_irqrestore(&uep->udc->lock, flags);
+
+	return ret;
+}
+
+static void isp1760_ep_fifo_flush(struct usb_ep *ep)
+{
+	struct isp1760_ep *uep = ep_to_udc_ep(ep);
+	struct isp1760_udc *udc = uep->udc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	isp1760_udc_select_ep(uep);
+
+	/*
+	 * Set the CLBUF bit twice to flush both buffers in case double
+	 * buffering is enabled.
+	 */
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_CLBUF);
+	isp1760_udc_write(udc, DC_CTRLFUNC, DC_CLBUF);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
+static const struct usb_ep_ops isp1760_ep_ops = {
+	.enable = isp1760_ep_enable,
+	.disable = isp1760_ep_disable,
+	.alloc_request = isp1760_ep_alloc_request,
+	.free_request = isp1760_ep_free_request,
+	.queue = isp1760_ep_queue,
+	.dequeue = isp1760_ep_dequeue,
+	.set_halt = isp1760_ep_set_halt,
+	.set_wedge = isp1760_ep_set_wedge,
+	.fifo_flush = isp1760_ep_fifo_flush,
+};
+
+/* -----------------------------------------------------------------------------
+ * Device States
+ */
+
+/* Called with the UDC spinlock held. */
+static void isp1760_udc_connect(struct isp1760_udc *udc)
+{
+	usb_gadget_set_state(&udc->gadget, USB_STATE_POWERED);
+	mod_timer(&udc->vbus_timer, jiffies + ISP1760_VBUS_POLL_INTERVAL);
+}
+
+/* Called with the UDC spinlock held. */
+static void isp1760_udc_disconnect(struct isp1760_udc *udc)
+{
+	if (udc->gadget.state < USB_STATE_POWERED)
+		return;
+
+	dev_dbg(udc->isp->dev, "Device disconnected in state %u\n",
+		 udc->gadget.state);
+
+	udc->gadget.speed = USB_SPEED_UNKNOWN;
+	usb_gadget_set_state(&udc->gadget, USB_STATE_ATTACHED);
+
+	if (udc->driver->disconnect)
+		udc->driver->disconnect(&udc->gadget);
+
+	del_timer(&udc->vbus_timer);
+
+	/* TODO Reset all endpoints ? */
+}
+
+static void isp1760_udc_init_hw(struct isp1760_udc *udc)
+{
+	/*
+	 * The device controller currently shares its interrupt with the host
+	 * controller, the DC_IRQ polarity and signaling mode are ignored. Set
+	 * the to active-low level-triggered.
+	 *
+	 * Configure the control, in and out pipes to generate interrupts on
+	 * ACK tokens only (and NYET for the out pipe). The default
+	 * configuration also generates an interrupt on the first NACK token.
+	 */
+	isp1760_udc_write(udc, DC_INTCONF, DC_CDBGMOD_ACK | DC_DDBGMODIN_ACK |
+			  DC_DDBGMODOUT_ACK_NYET);
+
+	isp1760_udc_write(udc, DC_INTENABLE, DC_IEPRXTX(7) | DC_IEPRXTX(6) |
+			  DC_IEPRXTX(5) | DC_IEPRXTX(4) | DC_IEPRXTX(3) |
+			  DC_IEPRXTX(2) | DC_IEPRXTX(1) | DC_IEPRXTX(0) |
+			  DC_IEP0SETUP | DC_IEVBUS | DC_IERESM | DC_IESUSP |
+			  DC_IEHS_STA | DC_IEBRST);
+
+	if (udc->connected)
+		isp1760_set_pullup(udc->isp, true);
+
+	isp1760_udc_write(udc, DC_ADDRESS, DC_DEVEN);
+}
+
+static void isp1760_udc_reset(struct isp1760_udc *udc)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	/*
+	 * The bus reset has reset most registers to their default value,
+	 * reinitialize the UDC hardware.
+	 */
+	isp1760_udc_init_hw(udc);
+
+	udc->ep0_state = ISP1760_CTRL_SETUP;
+	udc->gadget.speed = USB_SPEED_FULL;
+
+	usb_gadget_udc_reset(&udc->gadget, udc->driver);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
+static void isp1760_udc_suspend(struct isp1760_udc *udc)
+{
+	if (udc->gadget.state < USB_STATE_DEFAULT)
+		return;
+
+	if (udc->driver->suspend)
+		udc->driver->suspend(&udc->gadget);
+}
+
+static void isp1760_udc_resume(struct isp1760_udc *udc)
+{
+	if (udc->gadget.state < USB_STATE_DEFAULT)
+		return;
+
+	if (udc->driver->resume)
+		udc->driver->resume(&udc->gadget);
+}
+
+/* -----------------------------------------------------------------------------
+ * Gadget Operations
+ */
+
+static int isp1760_udc_get_frame(struct usb_gadget *gadget)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	return isp1760_udc_read(udc, DC_FRAMENUM) & ((1 << 11) - 1);
+}
+
+static int isp1760_udc_wakeup(struct usb_gadget *gadget)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	dev_dbg(udc->isp->dev, "%s\n", __func__);
+	return -ENOTSUPP;
+}
+
+static int isp1760_udc_set_selfpowered(struct usb_gadget *gadget,
+				       int is_selfpowered)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	if (is_selfpowered)
+		udc->devstatus |= 1 << USB_DEVICE_SELF_POWERED;
+	else
+		udc->devstatus &= ~(1 << USB_DEVICE_SELF_POWERED);
+
+	return 0;
+}
+
+static int isp1760_udc_pullup(struct usb_gadget *gadget, int is_on)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	isp1760_set_pullup(udc->isp, is_on);
+	udc->connected = is_on;
+
+	return 0;
+}
+
+static int isp1760_udc_start(struct usb_gadget *gadget,
+			     struct usb_gadget_driver *driver)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	/* The hardware doesn't support low speed. */
+	if (driver->max_speed < USB_SPEED_FULL) {
+		dev_err(udc->isp->dev, "Invalid gadget driver\n");
+		return -EINVAL;
+	}
+
+	spin_lock(&udc->lock);
+
+	if (udc->driver) {
+		dev_err(udc->isp->dev, "UDC already has a gadget driver\n");
+		spin_unlock(&udc->lock);
+		return -EBUSY;
+	}
+
+	udc->driver = driver;
+
+	spin_unlock(&udc->lock);
+
+	dev_dbg(udc->isp->dev, "starting UDC with driver %s\n",
+		driver->function);
+
+	udc->devstatus = 0;
+	udc->connected = true;
+
+	usb_gadget_set_state(&udc->gadget, USB_STATE_ATTACHED);
+
+	/* DMA isn't supported yet, don't enable the DMA clock. */
+	isp1760_udc_write(udc, DC_MODE, DC_GLINTENA);
+
+	isp1760_udc_init_hw(udc);
+
+	dev_dbg(udc->isp->dev, "UDC started with driver %s\n",
+		driver->function);
+
+	return 0;
+}
+
+static int isp1760_udc_stop(struct usb_gadget *gadget)
+{
+	struct isp1760_udc *udc = gadget_to_udc(gadget);
+
+	dev_dbg(udc->isp->dev, "%s\n", __func__);
+
+	del_timer_sync(&udc->vbus_timer);
+
+	isp1760_udc_write(udc, DC_MODE, 0);
+
+	spin_lock(&udc->lock);
+	udc->driver = NULL;
+	spin_unlock(&udc->lock);
+
+	return 0;
+}
+
+static struct usb_gadget_ops isp1760_udc_ops = {
+	.get_frame = isp1760_udc_get_frame,
+	.wakeup = isp1760_udc_wakeup,
+	.set_selfpowered = isp1760_udc_set_selfpowered,
+	.pullup = isp1760_udc_pullup,
+	.udc_start = isp1760_udc_start,
+	.udc_stop = isp1760_udc_stop,
+};
+
+/* -----------------------------------------------------------------------------
+ * Interrupt Handling
+ */
+
+static irqreturn_t isp1760_udc_irq(int irq, void *dev)
+{
+	struct isp1760_udc *udc = dev;
+	unsigned int i;
+	u32 status;
+
+	status = isp1760_udc_read(udc, DC_INTERRUPT)
+	       & isp1760_udc_read(udc, DC_INTENABLE);
+	isp1760_udc_write(udc, DC_INTERRUPT, status);
+
+	if (status & DC_IEVBUS) {
+		dev_dbg(udc->isp->dev, "%s(VBUS)\n", __func__);
+		/* The VBUS interrupt is only triggered when VBUS appears. */
+		spin_lock(&udc->lock);
+		isp1760_udc_connect(udc);
+		spin_unlock(&udc->lock);
+	}
+
+	if (status & DC_IEBRST) {
+		dev_dbg(udc->isp->dev, "%s(BRST)\n", __func__);
+
+		isp1760_udc_reset(udc);
+	}
+
+	for (i = 0; i <= 7; ++i) {
+		struct isp1760_ep *ep = &udc->ep[i*2];
+
+		if (status & DC_IEPTX(i)) {
+			dev_dbg(udc->isp->dev, "%s(EPTX%u)\n", __func__, i);
+			isp1760_ep_tx_complete(ep);
+		}
+
+		if (status & DC_IEPRX(i)) {
+			dev_dbg(udc->isp->dev, "%s(EPRX%u)\n", __func__, i);
+			isp1760_ep_rx_ready(i ? ep - 1 : ep);
+		}
+	}
+
+	if (status & DC_IEP0SETUP) {
+		dev_dbg(udc->isp->dev, "%s(EP0SETUP)\n", __func__);
+
+		isp1760_ep0_setup(udc);
+	}
+
+	if (status & DC_IERESM) {
+		dev_dbg(udc->isp->dev, "%s(RESM)\n", __func__);
+		isp1760_udc_resume(udc);
+	}
+
+	if (status & DC_IESUSP) {
+		dev_dbg(udc->isp->dev, "%s(SUSP)\n", __func__);
+
+		spin_lock(&udc->lock);
+		if (!(isp1760_udc_read(udc, DC_MODE) & DC_VBUSSTAT))
+			isp1760_udc_disconnect(udc);
+		else
+			isp1760_udc_suspend(udc);
+		spin_unlock(&udc->lock);
+	}
+
+	if (status & DC_IEHS_STA) {
+		dev_dbg(udc->isp->dev, "%s(HS_STA)\n", __func__);
+		udc->gadget.speed = USB_SPEED_HIGH;
+	}
+
+	return status ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static void isp1760_udc_vbus_poll(unsigned long data)
+{
+	struct isp1760_udc *udc = (struct isp1760_udc *)data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&udc->lock, flags);
+
+	if (!(isp1760_udc_read(udc, DC_MODE) & DC_VBUSSTAT))
+		isp1760_udc_disconnect(udc);
+	else if (udc->gadget.state >= USB_STATE_POWERED)
+		mod_timer(&udc->vbus_timer,
+			  jiffies + ISP1760_VBUS_POLL_INTERVAL);
+
+	spin_unlock_irqrestore(&udc->lock, flags);
+}
+
+/* -----------------------------------------------------------------------------
+ * Registration
+ */
+
+static void isp1760_udc_init_eps(struct isp1760_udc *udc)
+{
+	unsigned int i;
+
+	INIT_LIST_HEAD(&udc->gadget.ep_list);
+
+	for (i = 0; i < ARRAY_SIZE(udc->ep); ++i) {
+		struct isp1760_ep *ep = &udc->ep[i];
+		unsigned int ep_num = (i + 1) / 2;
+		bool is_in = !(i & 1);
+
+		ep->udc = udc;
+
+		INIT_LIST_HEAD(&ep->queue);
+
+		ep->addr = (ep_num && is_in ? USB_DIR_IN : USB_DIR_OUT)
+			 | ep_num;
+		ep->desc = NULL;
+
+		sprintf(ep->name, "ep%u%s", ep_num,
+			ep_num ? (is_in ? "in" : "out") : "");
+
+		ep->ep.ops = &isp1760_ep_ops;
+		ep->ep.name = ep->name;
+
+		/*
+		 * Hardcode the maximum packet sizes for now, to 64 bytes for
+		 * the control endpoint and 512 bytes for all other endpoints.
+		 * This fits in the 8kB FIFO without double-buffering.
+		 */
+		if (ep_num == 0) {
+			ep->ep.maxpacket = 64;
+			ep->maxpacket = 64;
+			udc->gadget.ep0 = &ep->ep;
+		} else {
+			ep->ep.maxpacket = 512;
+			ep->maxpacket = 0;
+			list_add_tail(&ep->ep.ep_list, &udc->gadget.ep_list);
+		}
+	}
+}
+
+static int isp1760_udc_init(struct isp1760_udc *udc)
+{
+	u16 scratch;
+	u32 chipid;
+
+	/*
+	 * Check that the controller is present by writing to the scratch
+	 * register, modifying the bus pattern by reading from the chip ID
+	 * register, and reading the scratch register value back. The chip ID
+	 * and scratch register contents must match the expected values.
+	 */
+	isp1760_udc_write(udc, DC_SCRATCH, 0xbabe);
+	chipid = isp1760_udc_read(udc, DC_CHIPID);
+	scratch = isp1760_udc_read(udc, DC_SCRATCH);
+
+	if (scratch != 0xbabe) {
+		dev_err(udc->isp->dev,
+			"udc: scratch test failed (0x%04x/0x%08x)\n",
+			scratch, chipid);
+		return -ENODEV;
+	}
+
+	if (chipid != 0x00011582) {
+		dev_err(udc->isp->dev, "udc: invalid chip ID 0x%08x\n", chipid);
+		return -ENODEV;
+	}
+
+	/* Reset the device controller. */
+	isp1760_udc_write(udc, DC_MODE, DC_SFRESET);
+	usleep_range(10000, 11000);
+	isp1760_udc_write(udc, DC_MODE, 0);
+	usleep_range(10000, 11000);
+
+	return 0;
+}
+
+int isp1760_udc_register(struct isp1760_device *isp, int irq,
+			 unsigned long irqflags)
+{
+	struct isp1760_udc *udc = &isp->udc;
+	const char *devname;
+	int ret;
+
+	udc->irq = -1;
+	udc->isp = isp;
+	udc->regs = isp->regs;
+
+	spin_lock_init(&udc->lock);
+	setup_timer(&udc->vbus_timer, isp1760_udc_vbus_poll,
+		    (unsigned long)udc);
+
+	ret = isp1760_udc_init(udc);
+	if (ret < 0)
+		return ret;
+
+	devname = dev_name(isp->dev);
+	udc->irqname = kmalloc(strlen(devname) + 7, GFP_KERNEL);
+	if (!udc->irqname)
+		return -ENOMEM;
+
+	sprintf(udc->irqname, "%s (udc)", devname);
+
+	ret = request_irq(irq, isp1760_udc_irq, IRQF_SHARED | IRQF_DISABLED |
+			  irqflags, udc->irqname, udc);
+	if (ret < 0)
+		goto error;
+
+	udc->irq = irq;
+
+	/*
+	 * Initialize the gadget static fields and register its device. Gadget
+	 * fields that vary during the life time of the gadget are initialized
+	 * by the UDC core.
+	 */
+	udc->gadget.ops = &isp1760_udc_ops;
+	udc->gadget.speed = USB_SPEED_UNKNOWN;
+	udc->gadget.max_speed = USB_SPEED_HIGH;
+	udc->gadget.name = "isp1761_udc";
+
+	isp1760_udc_init_eps(udc);
+
+	ret = usb_add_gadget_udc(isp->dev, &udc->gadget);
+	if (ret < 0)
+		goto error;
+
+	return 0;
+
+error:
+	if (udc->irq >= 0)
+		free_irq(udc->irq, udc);
+	kfree(udc->irqname);
+
+	return ret;
+}
+
+void isp1760_udc_unregister(struct isp1760_device *isp)
+{
+	struct isp1760_udc *udc = &isp->udc;
+
+	usb_del_gadget_udc(&udc->gadget);
+
+	free_irq(udc->irq, udc);
+	kfree(udc->irqname);
+}

drivers/usb/host/isp1760-udc.h

···
+/*
+ * Driver for the NXP ISP1761 device controller
+ *
+ * Copyright 2014 Ideas on Board Oy
+ *
+ * Contacts:
+ *	Laurent Pinchart <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#ifndef _ISP1760_UDC_H_
+#define _ISP1760_UDC_H_
+
+#include <linux/ioport.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/usb/gadget.h>
+
+struct isp1760_device;
+struct isp1760_udc;
+
+enum isp1760_ctrl_state {
+	ISP1760_CTRL_SETUP,		/* Waiting for a SETUP transaction */
+	ISP1760_CTRL_DATA_IN,		/* Setup received, data IN stage */
+	ISP1760_CTRL_DATA_OUT,		/* Setup received, data OUT stage */
+	ISP1760_CTRL_STATUS,		/* 0-length request in status stage */
+};
+
+struct isp1760_ep {
+	struct isp1760_udc *udc;
+	struct usb_ep ep;
+
+	struct list_head queue;
+
+	unsigned int addr;
+	unsigned int maxpacket;
+	char name[7];
+
+	const struct usb_endpoint_descriptor *desc;
+
+	bool rx_pending;
+	bool halted;
+	bool wedged;
+};
+
+/**
+ * struct isp1760_udc - UDC state information
+ * irq: IRQ number
+ * irqname: IRQ name (as passed to request_irq)
+ * regs: Base address of the UDC registers
+ * driver: Gadget driver
+ * gadget: Gadget device
+ * lock: Protects driver, vbus_timer, ep, ep0_*, DC_EPINDEX register
+ * ep: Array of endpoints
+ * ep0_state: Control request state for endpoint 0
+ * ep0_dir: Direction of the current control request
+ * ep0_length: Length of the current control request
+ * connected: Tracks gadget driver bus connection state
+ */
+struct isp1760_udc {
+#if CONFIG_USB_ISP1761_UDC
+	struct isp1760_device *isp;
+
+	int irq;
+	char *irqname;
+	void __iomem *regs;
+
+	struct usb_gadget_driver *driver;
+	struct usb_gadget gadget;
+
+	spinlock_t lock;
+	struct timer_list vbus_timer;
+
+	struct isp1760_ep ep[15];
+
+	enum isp1760_ctrl_state ep0_state;
+	u8 ep0_dir;
+	u16 ep0_length;
+
+	bool connected;
+
+	unsigned int devstatus;
+#endif
+};
+
+#if CONFIG_USB_ISP1761_UDC
+int isp1760_udc_register(struct isp1760_device *isp, int irq,
+			 unsigned long irqflags);
+void isp1760_udc_unregister(struct isp1760_device *isp);
+#else
+static inline int isp1760_udc_register(struct isp1760_device *isp, int irq,
+				       unsigned long irqflags)
+{
+	return 0;
+}
+
+static inline void isp1760_udc_unregister(struct isp1760_device *isp)
+{
+}
+#endif
+
+#endif