zte's code,first commit

Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/drivers/usb/dwc3/ep0.c b/ap/os/linux/linux-3.4.x/drivers/usb/dwc3/ep0.c
new file mode 100644
index 0000000..a8714fd
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/usb/dwc3/ep0.c
@@ -0,0 +1,878 @@
+/**
+ * ep0.c - DesignWare USB3 DRD Controller Endpoint 0 Handling
+ *
+ * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Authors: Felipe Balbi <balbi@ti.com>,
+ *	    Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2, as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/dma-mapping.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
+
+#include "core.h"
+#include "gadget.h"
+#include "io.h"
+
+static void dwc3_ep0_do_control_status(struct dwc3 *dwc, u32 epnum);
+
+static const char *dwc3_ep0_state_string(enum dwc3_ep0_state state)
+{
+	switch (state) {
+	case EP0_UNCONNECTED:
+		return "Unconnected";
+	case EP0_SETUP_PHASE:
+		return "Setup Phase";
+	case EP0_DATA_PHASE:
+		return "Data Phase";
+	case EP0_STATUS_PHASE:
+		return "Status Phase";
+	default:
+		return "UNKNOWN";
+	}
+}
+
+static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
+		u32 len, u32 type)
+{
+	struct dwc3_gadget_ep_cmd_params params;
+	struct dwc3_trb			*trb;
+	struct dwc3_ep			*dep;
+
+	int				ret;
+
+	dep = dwc->eps[epnum];
+	if (dep->flags & DWC3_EP_BUSY) {
+		dev_vdbg(dwc->dev, "%s: still busy\n", dep->name);
+		return 0;
+	}
+
+	trb = dwc->ep0_trb;
+
+	trb->bpl = lower_32_bits(buf_dma);
+	trb->bph = upper_32_bits(buf_dma);
+	trb->size = len;
+	trb->ctrl = type;
+
+	trb->ctrl |= (DWC3_TRB_CTRL_HWO
+			| DWC3_TRB_CTRL_LST
+			| DWC3_TRB_CTRL_IOC
+			| DWC3_TRB_CTRL_ISP_IMI);
+
+	memset(&params, 0, sizeof(params));
+	params.param0 = upper_32_bits(dwc->ep0_trb_addr);
+	params.param1 = lower_32_bits(dwc->ep0_trb_addr);
+
+	ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
+			DWC3_DEPCMD_STARTTRANSFER, &params);
+	if (ret < 0) {
+		dev_dbg(dwc->dev, "failed to send STARTTRANSFER command\n");
+		return ret;
+	}
+
+	dep->flags |= DWC3_EP_BUSY;
+	dep->res_trans_idx = dwc3_gadget_ep_get_transfer_index(dwc,
+			dep->number);
+
+	dwc->ep0_next_event = DWC3_EP0_COMPLETE;
+
+	return 0;
+}
+
+static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
+		struct dwc3_request *req)
+{
+	struct dwc3		*dwc = dep->dwc;
+	int			ret = 0;
+
+	req->request.actual	= 0;
+	req->request.status	= -EINPROGRESS;
+	req->epnum		= dep->number;
+
+	list_add_tail(&req->list, &dep->request_list);
+
+	/*
+	 * Gadget driver might not be quick enough to queue a request
+	 * before we get a Transfer Not Ready event on this endpoint.
+	 *
+	 * In that case, we will set DWC3_EP_PENDING_REQUEST. When that
+	 * flag is set, it's telling us that as soon as Gadget queues the
+	 * required request, we should kick the transfer here because the
+	 * IRQ we were waiting for is long gone.
+	 */
+	if (dep->flags & DWC3_EP_PENDING_REQUEST) {
+		unsigned	direction;
+
+		direction = !!(dep->flags & DWC3_EP0_DIR_IN);
+
+		if (dwc->ep0state != EP0_DATA_PHASE) {
+			dev_WARN(dwc->dev, "Unexpected pending request\n");
+			return 0;
+		}
+
+		ret = dwc3_ep0_start_trans(dwc, direction,
+				req->request.dma, req->request.length,
+				DWC3_TRBCTL_CONTROL_DATA);
+		dep->flags &= ~(DWC3_EP_PENDING_REQUEST |
+				DWC3_EP0_DIR_IN);
+	} else if (dwc->delayed_status) {
+		dwc->delayed_status = false;
+
+		if (dwc->ep0state == EP0_STATUS_PHASE)
+			dwc3_ep0_do_control_status(dwc, 1);
+		else
+			dev_dbg(dwc->dev, "too early for delayed status\n");
+	}
+
+	return ret;
+}
+
+int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
+		gfp_t gfp_flags)
+{
+	struct dwc3_request		*req = to_dwc3_request(request);
+	struct dwc3_ep			*dep = to_dwc3_ep(ep);
+	struct dwc3			*dwc = dep->dwc;
+
+	unsigned long			flags;
+
+	int				ret;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	if (!dep->desc) {
+		dev_dbg(dwc->dev, "trying to queue request %p to disabled %s\n",
+				request, dep->name);
+		ret = -ESHUTDOWN;
+		goto out;
+	}
+
+	/* we share one TRB for ep0/1 */
+	if (!list_empty(&dep->request_list)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	dev_vdbg(dwc->dev, "queueing request %p to %s length %d, state '%s'\n",
+			request, dep->name, request->length,
+			dwc3_ep0_state_string(dwc->ep0state));
+
+	ret = __dwc3_gadget_ep0_queue(dep, req);
+
+out:
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return ret;
+}
+
+static void dwc3_ep0_stall_and_restart(struct dwc3 *dwc)
+{
+	struct dwc3_ep		*dep = dwc->eps[0];
+
+	/* stall is always issued on EP0 */
+	__dwc3_gadget_ep_set_halt(dep, 1, false);
+	dep->flags = DWC3_EP_ENABLED;
+	dwc->delayed_status = false;
+
+	if (!list_empty(&dep->request_list)) {
+		struct dwc3_request	*req;
+
+		req = next_request(&dep->request_list);
+		dwc3_gadget_giveback(dep, req, -ECONNRESET);
+	}
+
+	dwc->ep0state = EP0_SETUP_PHASE;
+	dwc3_ep0_out_start(dwc);
+}
+
+void dwc3_ep0_out_start(struct dwc3 *dwc)
+{
+	int				ret;
+
+	ret = dwc3_ep0_start_trans(dwc, 0, dwc->ctrl_req_addr, 8,
+			DWC3_TRBCTL_CONTROL_SETUP);
+	WARN_ON(ret < 0);
+}
+
+static struct dwc3_ep *dwc3_wIndex_to_dep(struct dwc3 *dwc, __le16 wIndex_le)
+{
+	struct dwc3_ep		*dep;
+	u32			windex = le16_to_cpu(wIndex_le);
+	u32			epnum;
+
+	epnum = (windex & USB_ENDPOINT_NUMBER_MASK) << 1;
+	if ((windex & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN)
+		epnum |= 1;
+
+	dep = dwc->eps[epnum];
+	if (dep->flags & DWC3_EP_ENABLED)
+		return dep;
+
+	return NULL;
+}
+
+static void dwc3_ep0_status_cmpl(struct usb_ep *ep, struct usb_request *req)
+{
+}
+/*
+ * ch 9.4.5
+ */
+static int dwc3_ep0_handle_status(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl)
+{
+	struct dwc3_ep		*dep;
+	u32			recip;
+	u16			usb_status = 0;
+	__le16			*response_pkt;
+
+	recip = ctrl->bRequestType & USB_RECIP_MASK;
+	switch (recip) {
+	case USB_RECIP_DEVICE:
+		/*
+		 * We are self-powered. U1/U2/LTM will be set later
+		 * once we handle this states. RemoteWakeup is 0 on SS
+		 */
+		usb_status |= dwc->is_selfpowered << USB_DEVICE_SELF_POWERED;
+		break;
+
+	case USB_RECIP_INTERFACE:
+		/*
+		 * Function Remote Wake Capable	D0
+		 * Function Remote Wakeup	D1
+		 */
+		break;
+
+	case USB_RECIP_ENDPOINT:
+		dep = dwc3_wIndex_to_dep(dwc, ctrl->wIndex);
+		if (!dep)
+			return -EINVAL;
+
+		if (dep->flags & DWC3_EP_STALL)
+			usb_status = 1 << USB_ENDPOINT_HALT;
+		break;
+	default:
+		return -EINVAL;
+	};
+
+	response_pkt = (__le16 *) dwc->setup_buf;
+	*response_pkt = cpu_to_le16(usb_status);
+
+	dep = dwc->eps[0];
+	dwc->ep0_usb_req.dep = dep;
+	dwc->ep0_usb_req.request.length = sizeof(*response_pkt);
+	dwc->ep0_usb_req.request.buf = dwc->setup_buf;
+	dwc->ep0_usb_req.request.complete = dwc3_ep0_status_cmpl;
+
+	return __dwc3_gadget_ep0_queue(dep, &dwc->ep0_usb_req);
+}
+
+static int dwc3_ep0_handle_feature(struct dwc3 *dwc,
+		struct usb_ctrlrequest *ctrl, int set)
+{
+	struct dwc3_ep		*dep;
+	u32			recip;
+	u32			wValue;
+	u32			wIndex;
+	int			ret;
+
+	wValue = le16_to_cpu(ctrl->wValue);
+	wIndex = le16_to_cpu(ctrl->wIndex);
+	recip = ctrl->bRequestType & USB_RECIP_MASK;
+	switch (recip) {
+	case USB_RECIP_DEVICE:
+
+		/*
+		 * 9.4.1 says only only for SS, in AddressState only for
+		 * default control pipe
+		 */
+		switch (wValue) {
+		case USB_DEVICE_U1_ENABLE:
+		case USB_DEVICE_U2_ENABLE:
+		case USB_DEVICE_LTM_ENABLE:
+			if (dwc->dev_state != DWC3_CONFIGURED_STATE)
+				return -EINVAL;
+			if (dwc->speed != DWC3_DSTS_SUPERSPEED)
+				return -EINVAL;
+		}
+
+		/* XXX add U[12] & LTM */
+		switch (wValue) {
+		case USB_DEVICE_REMOTE_WAKEUP:
+			break;
+		case USB_DEVICE_U1_ENABLE:
+			break;
+		case USB_DEVICE_U2_ENABLE:
+			break;
+		case USB_DEVICE_LTM_ENABLE:
+			break;
+
+		case USB_DEVICE_TEST_MODE:
+			if ((wIndex & 0xff) != 0)
+				return -EINVAL;
+			if (!set)
+				return -EINVAL;
+
+			dwc->test_mode_nr = wIndex >> 8;
+			dwc->test_mode = true;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+	case USB_RECIP_INTERFACE:
+		switch (wValue) {
+		case USB_INTRF_FUNC_SUSPEND:
+			if (wIndex & USB_INTRF_FUNC_SUSPEND_LP)
+				/* XXX enable Low power suspend */
+				;
+			if (wIndex & USB_INTRF_FUNC_SUSPEND_RW)
+				/* XXX enable remote wakeup */
+				;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+	case USB_RECIP_ENDPOINT:
+		switch (wValue) {
+		case USB_ENDPOINT_HALT:
+			dep = dwc3_wIndex_to_dep(dwc, wIndex);
+			if (!dep)
+				return -EINVAL;
+			if (set == 0 && (dep->flags & DWC3_EP_WEDGE))
+				break;
+			ret = __dwc3_gadget_ep_set_halt(dep, set, true);
+			if (ret)
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+
+	default:
+		return -EINVAL;
+	};
+
+	return 0;
+}
+
+static int dwc3_ep0_set_address(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
+{
+	u32 addr;
+	u32 reg;
+
+	addr = le16_to_cpu(ctrl->wValue);
+	if (addr > 127) {
+		dev_dbg(dwc->dev, "invalid device address %d\n", addr);
+		return -EINVAL;
+	}
+
+	if (dwc->dev_state == DWC3_CONFIGURED_STATE) {
+		dev_dbg(dwc->dev, "trying to set address when configured\n");
+		return -EINVAL;
+	}
+
+	reg = dwc3_readl(dwc->regs, DWC3_DCFG);
+	reg &= ~(DWC3_DCFG_DEVADDR_MASK);
+	reg |= DWC3_DCFG_DEVADDR(addr);
+	dwc3_writel(dwc->regs, DWC3_DCFG, reg);
+
+	if (addr)
+		dwc->dev_state = DWC3_ADDRESS_STATE;
+	else
+		dwc->dev_state = DWC3_DEFAULT_STATE;
+
+	return 0;
+}
+
+static int dwc3_ep0_delegate_req(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
+{
+	int ret;
+
+	spin_unlock(&dwc->lock);
+	ret = dwc->gadget_driver->setup(&dwc->gadget, ctrl);
+	spin_lock(&dwc->lock);
+	return ret;
+}
+
+static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
+{
+	u32 cfg;
+	int ret;
+
+	dwc->start_config_issued = false;
+	cfg = le16_to_cpu(ctrl->wValue);
+
+	switch (dwc->dev_state) {
+	case DWC3_DEFAULT_STATE:
+		return -EINVAL;
+		break;
+
+	case DWC3_ADDRESS_STATE:
+		ret = dwc3_ep0_delegate_req(dwc, ctrl);
+		/* if the cfg matches and the cfg is non zero */
+		if (cfg && (!ret || (ret == USB_GADGET_DELAYED_STATUS))) {
+			dwc->dev_state = DWC3_CONFIGURED_STATE;
+			dwc->resize_fifos = true;
+			dev_dbg(dwc->dev, "resize fifos flag SET\n");
+		}
+		break;
+
+	case DWC3_CONFIGURED_STATE:
+		ret = dwc3_ep0_delegate_req(dwc, ctrl);
+		if (!cfg)
+			dwc->dev_state = DWC3_ADDRESS_STATE;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
+{
+	int ret;
+
+	switch (ctrl->bRequest) {
+	case USB_REQ_GET_STATUS:
+		dev_vdbg(dwc->dev, "USB_REQ_GET_STATUS\n");
+		ret = dwc3_ep0_handle_status(dwc, ctrl);
+		break;
+	case USB_REQ_CLEAR_FEATURE:
+		dev_vdbg(dwc->dev, "USB_REQ_CLEAR_FEATURE\n");
+		ret = dwc3_ep0_handle_feature(dwc, ctrl, 0);
+		break;
+	case USB_REQ_SET_FEATURE:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_FEATURE\n");
+		ret = dwc3_ep0_handle_feature(dwc, ctrl, 1);
+		break;
+	case USB_REQ_SET_ADDRESS:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_ADDRESS\n");
+		ret = dwc3_ep0_set_address(dwc, ctrl);
+		break;
+	case USB_REQ_SET_CONFIGURATION:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_CONFIGURATION\n");
+		ret = dwc3_ep0_set_config(dwc, ctrl);
+		break;
+	default:
+		dev_vdbg(dwc->dev, "Forwarding to gadget driver\n");
+		ret = dwc3_ep0_delegate_req(dwc, ctrl);
+		break;
+	};
+
+	return ret;
+}
+
+static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	struct usb_ctrlrequest *ctrl = dwc->ctrl_req;
+	int ret;
+	u32 len;
+
+	if (!dwc->gadget_driver)
+		goto err;
+
+	len = le16_to_cpu(ctrl->wLength);
+	if (!len) {
+		dwc->three_stage_setup = false;
+		dwc->ep0_expect_in = false;
+		dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
+	} else {
+		dwc->three_stage_setup = true;
+		dwc->ep0_expect_in = !!(ctrl->bRequestType & USB_DIR_IN);
+		dwc->ep0_next_event = DWC3_EP0_NRDY_DATA;
+	}
+
+	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
+		ret = dwc3_ep0_std_request(dwc, ctrl);
+	else
+		ret = dwc3_ep0_delegate_req(dwc, ctrl);
+
+	if (ret == USB_GADGET_DELAYED_STATUS)
+		dwc->delayed_status = true;
+
+	if (ret >= 0)
+		return;
+
+err:
+	dwc3_ep0_stall_and_restart(dwc);
+}
+
+static void dwc3_ep0_complete_data(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	struct dwc3_request	*r = NULL;
+	struct usb_request	*ur;
+	struct dwc3_trb		*trb;
+	struct dwc3_ep		*ep0;
+	u32			transferred;
+	u32			length;
+	u8			epnum;
+
+	epnum = event->endpoint_number;
+	ep0 = dwc->eps[0];
+
+	dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
+
+	r = next_request(&ep0->request_list);
+	ur = &r->request;
+
+	trb = dwc->ep0_trb;
+	length = trb->size & DWC3_TRB_SIZE_MASK;
+
+	if (dwc->ep0_bounced) {
+		unsigned transfer_size = ur->length;
+		unsigned maxp = ep0->endpoint.maxpacket;
+
+		transfer_size += (maxp - (transfer_size % maxp));
+		transferred = min_t(u32, ur->length,
+				transfer_size - length);
+		memcpy(ur->buf, dwc->ep0_bounce, transferred);
+	} else {
+		transferred = ur->length - length;
+	}
+
+	ur->actual += transferred;
+
+	if ((epnum & 1) && ur->actual < ur->length) {
+		/* for some reason we did not get everything out */
+
+		dwc3_ep0_stall_and_restart(dwc);
+	} else {
+		/*
+		 * handle the case where we have to send a zero packet. This
+		 * seems to be case when req.length > maxpacket. Could it be?
+		 */
+		if (r)
+			dwc3_gadget_giveback(ep0, r, 0);
+	}
+}
+
+static void dwc3_ep0_complete_req(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	struct dwc3_request	*r;
+	struct dwc3_ep		*dep;
+
+	dep = dwc->eps[0];
+
+	if (!list_empty(&dep->request_list)) {
+		r = next_request(&dep->request_list);
+
+		dwc3_gadget_giveback(dep, r, 0);
+	}
+
+	if (dwc->test_mode) {
+		int ret;
+
+		ret = dwc3_gadget_set_test_mode(dwc, dwc->test_mode_nr);
+		if (ret < 0) {
+			dev_dbg(dwc->dev, "Invalid Test #%d\n",
+					dwc->test_mode_nr);
+			dwc3_ep0_stall_and_restart(dwc);
+		}
+	}
+
+	dwc->ep0state = EP0_SETUP_PHASE;
+	dwc3_ep0_out_start(dwc);
+}
+
+static void dwc3_ep0_xfer_complete(struct dwc3 *dwc,
+			const struct dwc3_event_depevt *event)
+{
+	struct dwc3_ep		*dep = dwc->eps[event->endpoint_number];
+
+	dep->flags &= ~DWC3_EP_BUSY;
+	dep->res_trans_idx = 0;
+	dwc->setup_packet_pending = false;
+
+	switch (dwc->ep0state) {
+	case EP0_SETUP_PHASE:
+		dev_vdbg(dwc->dev, "Inspecting Setup Bytes\n");
+		dwc3_ep0_inspect_setup(dwc, event);
+		break;
+
+	case EP0_DATA_PHASE:
+		dev_vdbg(dwc->dev, "Data Phase\n");
+		dwc3_ep0_complete_data(dwc, event);
+		break;
+
+	case EP0_STATUS_PHASE:
+		dev_vdbg(dwc->dev, "Status Phase\n");
+		dwc3_ep0_complete_req(dwc, event);
+		break;
+	case USB_REQ_SET_INTERFACE:
+		dev_vdbg(dwc->dev, "USB_REQ_SET_INTERFACE\n");
+		dwc->start_config_issued = false;
+		/* Fall through */
+	default:
+		WARN(true, "UNKNOWN ep0state %d\n", dwc->ep0state);
+	}
+}
+
+static void dwc3_ep0_do_control_setup(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	dwc3_ep0_out_start(dwc);
+}
+
+static void dwc3_ep0_do_control_data(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	struct dwc3_ep		*dep;
+	struct dwc3_request	*req;
+	int			ret;
+
+	dep = dwc->eps[0];
+
+	if (list_empty(&dep->request_list)) {
+		dev_vdbg(dwc->dev, "pending request for EP0 Data phase\n");
+		dep->flags |= DWC3_EP_PENDING_REQUEST;
+
+		if (event->endpoint_number)
+			dep->flags |= DWC3_EP0_DIR_IN;
+		return;
+	}
+
+	req = next_request(&dep->request_list);
+	req->direction = !!event->endpoint_number;
+
+	if (req->request.length == 0) {
+		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
+				dwc->ctrl_req_addr, 0,
+				DWC3_TRBCTL_CONTROL_DATA);
+	} else if ((req->request.length % dep->endpoint.maxpacket)
+			&& (event->endpoint_number == 0)) {
+		ret = usb_gadget_map_request(&dwc->gadget, &req->request,
+				event->endpoint_number);
+		if (ret) {
+			dev_dbg(dwc->dev, "failed to map request\n");
+			return;
+		}
+
+		WARN_ON(req->request.length > dep->endpoint.maxpacket);
+
+		dwc->ep0_bounced = true;
+
+		/*
+		 * REVISIT in case request length is bigger than EP0
+		 * wMaxPacketSize, we will need two chained TRBs to handle
+		 * the transfer.
+		 */
+		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
+				dwc->ep0_bounce_addr, dep->endpoint.maxpacket,
+				DWC3_TRBCTL_CONTROL_DATA);
+	} else {
+		ret = usb_gadget_map_request(&dwc->gadget, &req->request,
+				event->endpoint_number);
+		if (ret) {
+			dev_dbg(dwc->dev, "failed to map request\n");
+			return;
+		}
+
+		ret = dwc3_ep0_start_trans(dwc, event->endpoint_number,
+				req->request.dma, req->request.length,
+				DWC3_TRBCTL_CONTROL_DATA);
+	}
+
+	WARN_ON(ret < 0);
+}
+
+static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
+{
+	struct dwc3		*dwc = dep->dwc;
+	u32			type;
+
+	type = dwc->three_stage_setup ? DWC3_TRBCTL_CONTROL_STATUS3
+		: DWC3_TRBCTL_CONTROL_STATUS2;
+
+	return dwc3_ep0_start_trans(dwc, dep->number,
+			dwc->ctrl_req_addr, 0, type);
+}
+
+static void dwc3_ep0_do_control_status(struct dwc3 *dwc, u32 epnum)
+{
+	struct dwc3_ep		*dep = dwc->eps[epnum];
+
+	if (dwc->resize_fifos) {
+		dev_dbg(dwc->dev, "starting to resize fifos\n");
+		dwc3_gadget_resize_tx_fifos(dwc);
+		dwc->resize_fifos = 0;
+	}
+
+	WARN_ON(dwc3_ep0_start_control_status(dep));
+}
+
+static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	dwc->setup_packet_pending = true;
+
+	/*
+	 * This part is very tricky: If we has just handled
+	 * XferNotReady(Setup) and we're now expecting a
+	 * XferComplete but, instead, we receive another
+	 * XferNotReady(Setup), we should STALL and restart
+	 * the state machine.
+	 *
+	 * In all other cases, we just continue waiting
+	 * for the XferComplete event.
+	 *
+	 * We are a little bit unsafe here because we're
+	 * not trying to ensure that last event was, indeed,
+	 * XferNotReady(Setup).
+	 *
+	 * Still, we don't expect any condition where that
+	 * should happen and, even if it does, it would be
+	 * another error condition.
+	 */
+	if (dwc->ep0_next_event == DWC3_EP0_COMPLETE) {
+		switch (event->status) {
+		case DEPEVT_STATUS_CONTROL_SETUP:
+			dev_vdbg(dwc->dev, "Unexpected XferNotReady(Setup)\n");
+			dwc3_ep0_stall_and_restart(dwc);
+			break;
+		case DEPEVT_STATUS_CONTROL_DATA:
+			/* FALLTHROUGH */
+		case DEPEVT_STATUS_CONTROL_STATUS:
+			/* FALLTHROUGH */
+		default:
+			dev_vdbg(dwc->dev, "waiting for XferComplete\n");
+		}
+
+		return;
+	}
+
+	switch (event->status) {
+	case DEPEVT_STATUS_CONTROL_SETUP:
+		dev_vdbg(dwc->dev, "Control Setup\n");
+
+		dwc->ep0state = EP0_SETUP_PHASE;
+
+		dwc3_ep0_do_control_setup(dwc, event);
+		break;
+
+	case DEPEVT_STATUS_CONTROL_DATA:
+		dev_vdbg(dwc->dev, "Control Data\n");
+
+		dwc->ep0state = EP0_DATA_PHASE;
+
+		if (dwc->ep0_next_event != DWC3_EP0_NRDY_DATA) {
+			dev_vdbg(dwc->dev, "Expected %d got %d\n",
+					dwc->ep0_next_event,
+					DWC3_EP0_NRDY_DATA);
+
+			dwc3_ep0_stall_and_restart(dwc);
+			return;
+		}
+
+		/*
+		 * One of the possible error cases is when Host _does_
+		 * request for Data Phase, but it does so on the wrong
+		 * direction.
+		 *
+		 * Here, we already know ep0_next_event is DATA (see above),
+		 * so we only need to check for direction.
+		 */
+		if (dwc->ep0_expect_in != event->endpoint_number) {
+			dev_vdbg(dwc->dev, "Wrong direction for Data phase\n");
+			dwc3_ep0_stall_and_restart(dwc);
+			return;
+		}
+
+		dwc3_ep0_do_control_data(dwc, event);
+		break;
+
+	case DEPEVT_STATUS_CONTROL_STATUS:
+		dev_vdbg(dwc->dev, "Control Status\n");
+
+		dwc->ep0state = EP0_STATUS_PHASE;
+
+		if (dwc->ep0_next_event != DWC3_EP0_NRDY_STATUS) {
+			dev_vdbg(dwc->dev, "Expected %d got %d\n",
+					dwc->ep0_next_event,
+					DWC3_EP0_NRDY_STATUS);
+
+			dwc3_ep0_stall_and_restart(dwc);
+			return;
+		}
+
+		if (dwc->delayed_status) {
+			WARN_ON_ONCE(event->endpoint_number != 1);
+			dev_vdbg(dwc->dev, "Mass Storage delayed status\n");
+			return;
+		}
+
+		dwc3_ep0_do_control_status(dwc, event->endpoint_number);
+	}
+}
+
+void dwc3_ep0_interrupt(struct dwc3 *dwc,
+		const struct dwc3_event_depevt *event)
+{
+	u8			epnum = event->endpoint_number;
+
+	dev_dbg(dwc->dev, "%s while ep%d%s in state '%s'\n",
+			dwc3_ep_event_string(event->endpoint_event),
+			epnum >> 1, (epnum & 1) ? "in" : "out",
+			dwc3_ep0_state_string(dwc->ep0state));
+
+	switch (event->endpoint_event) {
+	case DWC3_DEPEVT_XFERCOMPLETE:
+		dwc3_ep0_xfer_complete(dwc, event);
+		break;
+
+	case DWC3_DEPEVT_XFERNOTREADY:
+		dwc3_ep0_xfernotready(dwc, event);
+		break;
+
+	case DWC3_DEPEVT_XFERINPROGRESS:
+	case DWC3_DEPEVT_RXTXFIFOEVT:
+	case DWC3_DEPEVT_STREAMEVT:
+	case DWC3_DEPEVT_EPCMDCMPLT:
+		break;
+	}
+}