Linux-libre 4.5-gnu

9 files changed, 305 insertions, 192 deletions

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 5a42c4590..a64ce1c94 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -87,6 +87,15 @@ config USB_DWC3_KEYSTONE
 	  Support of USB2/3 functionality in TI Keystone2 platforms.
 	  Say 'Y' or 'M' here if you have one such device
 
+config USB_DWC3_OF_SIMPLE
+       tristate "Generic OF Simple Glue Layer"
+       depends on OF && COMMON_CLK
+       default USB_DWC3
+       help
+         Support USB2/3 functionality in simple SoC integrations.
+	 Currently supports Xilinx and Qualcomm DWC USB3 IP.
+	 Say 'Y' or 'M' if you have one such device.
+
 config USB_DWC3_ST
 	tristate "STMicroelectronics Platforms"
 	depends on ARCH_STI && OF
@@ -96,12 +105,4 @@ config USB_DWC3_ST
 	  inside (i.e. STiH407).
 	  Say 'Y' or 'M' if you have one such device.
 
-config USB_DWC3_QCOM
-	tristate "Qualcomm Platforms"
-	depends on ARCH_QCOM || COMPILE_TEST
-	default USB_DWC3
-	help
-	  Recent Qualcomm SoCs ship with one DesignWare Core USB3 IP inside,
-	  say 'Y' or 'M' if you have one such device.
-
 endif
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index acc951d46..22420e17d 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -37,5 +37,5 @@ obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
 obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
 obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
-obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom.o
+obj-$(CONFIG_USB_DWC3_OF_SIMPLE)	+= dwc3-of-simple.o
 obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 22b479738..de5e01f41 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -272,7 +272,8 @@ static int dwc3_event_buffers_setup(struct dwc3 *dwc)
 
 	for (n = 0; n < dwc->num_event_buffers; n++) {
 		evt = dwc->ev_buffs[n];
-		dev_dbg(dwc->dev, "Event buf %p dma %08llx length %d\n",
+		dwc3_trace(trace_dwc3_core,
+				"Event buf %p dma %08llx length %d\n",
 				evt->buf, (unsigned long long) evt->dma,
 				evt->length);
 
@@ -608,12 +609,13 @@ static int dwc3_core_init(struct dwc3 *dwc)
 		reg |= DWC3_GCTL_GBLHIBERNATIONEN;
 		break;
 	default:
-		dev_dbg(dwc->dev, "No power optimization available\n");
+		dwc3_trace(trace_dwc3_core, "No power optimization available\n");
 	}
 
 	/* check if current dwc3 is on simulation board */
 	if (dwc->hwparams.hwparams6 & DWC3_GHWPARAMS6_EN_FPGA) {
-		dev_dbg(dwc->dev, "it is on FPGA board\n");
+		dwc3_trace(trace_dwc3_core,
+				"running on FPGA platform\n");
 		dwc->is_fpga = true;
 	}
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 78be201d8..e4f8b90d9 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -37,6 +37,7 @@
 #define DWC3_MSG_MAX	500
 
 /* Global constants */
+#define DWC3_ZLP_BUF_SIZE	1024	/* size of a superspeed bulk */
 #define DWC3_EP0_BOUNCE_SIZE	512
 #define DWC3_ENDPOINTS_NUM	32
 #define DWC3_XHCI_RESOURCES_NUM	2
@@ -647,6 +648,7 @@ struct dwc3_scratchpad_array {
  * @ctrl_req: usb control request which is used for ep0
  * @ep0_trb: trb which is used for the ctrl_req
  * @ep0_bounce: bounce buffer for ep0
+ * @zlp_buf: used when request->zero is set
  * @setup_buf: used while precessing STD USB requests
  * @ctrl_req_addr: dma address of ctrl_req
  * @ep0_trb: dma address of ep0_trb
@@ -734,6 +736,7 @@ struct dwc3 {
 	struct usb_ctrlrequest	*ctrl_req;
 	struct dwc3_trb		*ep0_trb;
 	void			*ep0_bounce;
+	void			*zlp_buf;
 	void			*scratchbuf;
 	u8			*setup_buf;
 	dma_addr_t		ctrl_req_addr;
diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
new file mode 100644
index 000000000..9c9f74155
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-of-simple.c
@@ -0,0 +1,180 @@
+/**
+ * dwc3-of-simple.c - OF glue layer for simple integrations
+ *
+ * Copyright (c) 2015 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * This is a combination of the old dwc3-qcom.c by Ivan T. Ivanov
+ * <iivanov@mm-sol.com> and the original patch adding support for Xilinx' SoC
+ * by Subbaraya Sundeep Bhatta <subbaraya.sundeep.bhatta@xilinx.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pm_runtime.h>
+
+struct dwc3_of_simple {
+	struct device		*dev;
+	struct clk		**clks;
+	int			num_clocks;
+};
+
+static int dwc3_of_simple_probe(struct platform_device *pdev)
+{
+	struct dwc3_of_simple	*simple;
+	struct device		*dev = &pdev->dev;
+	struct device_node	*np = dev->of_node;
+
+	int			ret;
+	int			i;
+
+	simple = devm_kzalloc(dev, sizeof(*simple), GFP_KERNEL);
+	if (!simple)
+		return -ENOMEM;
+
+	ret = of_clk_get_parent_count(np);
+	if (ret < 0)
+		return ret;
+
+	simple->num_clocks = ret;
+
+	simple->clks = devm_kcalloc(dev, simple->num_clocks,
+			sizeof(struct clk *), GFP_KERNEL);
+	if (!simple->clks)
+		return -ENOMEM;
+
+	simple->dev = dev;
+
+	for (i = 0; i < simple->num_clocks; i++) {
+		struct clk	*clk;
+
+		clk = of_clk_get(np, i);
+		if (IS_ERR(clk)) {
+			while (--i >= 0)
+				clk_put(simple->clks[i]);
+			return PTR_ERR(clk);
+		}
+
+		ret = clk_prepare_enable(clk);
+		if (ret < 0) {
+			while (--i >= 0) {
+				clk_disable_unprepare(simple->clks[i]);
+				clk_put(simple->clks[i]);
+			}
+			clk_put(clk);
+
+			return ret;
+		}
+
+		simple->clks[i] = clk;
+	}
+
+	ret = of_platform_populate(np, NULL, NULL, dev);
+	if (ret) {
+		for (i = 0; i < simple->num_clocks; i++) {
+			clk_disable_unprepare(simple->clks[i]);
+			clk_put(simple->clks[i]);
+		}
+
+		return ret;
+	}
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
+	return 0;
+}
+
+static int dwc3_of_simple_remove(struct platform_device *pdev)
+{
+	struct dwc3_of_simple	*simple = platform_get_drvdata(pdev);
+	struct device		*dev = &pdev->dev;
+	int			i;
+
+	for (i = 0; i < simple->num_clocks; i++) {
+		clk_unprepare(simple->clks[i]);
+		clk_put(simple->clks[i]);
+	}
+
+	of_platform_depopulate(dev);
+
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int dwc3_of_simple_runtime_suspend(struct device *dev)
+{
+	struct dwc3_of_simple	*simple = dev_get_drvdata(dev);
+	int			i;
+
+	for (i = 0; i < simple->num_clocks; i++)
+		clk_disable(simple->clks[i]);
+
+	return 0;
+}
+
+static int dwc3_of_simple_runtime_resume(struct device *dev)
+{
+	struct dwc3_of_simple	*simple = dev_get_drvdata(dev);
+	int			ret;
+	int			i;
+
+	for (i = 0; i < simple->num_clocks; i++) {
+		ret = clk_enable(simple->clks[i]);
+		if (ret < 0) {
+			while (--i >= 0)
+				clk_disable(simple->clks[i]);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops dwc3_of_simple_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(dwc3_of_simple_runtime_suspend,
+			dwc3_of_simple_runtime_resume, NULL)
+};
+
+static const struct of_device_id of_dwc3_simple_match[] = {
+	{ .compatible = "qcom,dwc3" },
+	{ .compatible = "xlnx,zynqmp-dwc3" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_dwc3_simple_match);
+
+static struct platform_driver dwc3_of_simple_driver = {
+	.probe		= dwc3_of_simple_probe,
+	.remove		= dwc3_of_simple_remove,
+	.driver		= {
+		.name	= "dwc3-of-simple",
+		.of_match_table = of_dwc3_simple_match,
+	},
+};
+
+module_platform_driver(dwc3_of_simple_driver);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("DesignWare USB3 OF Simple Glue Layer");
+MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
deleted file mode 100644
index 088026048..000000000
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ /dev/null
@@ -1,130 +0,0 @@
-/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-#include <linux/clk.h>
-#include <linux/err.h>
-#include <linux/io.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/of_platform.h>
-#include <linux/platform_device.h>
-
-struct dwc3_qcom {
-	struct device		*dev;
-
-	struct clk		*core_clk;
-	struct clk		*iface_clk;
-	struct clk		*sleep_clk;
-};
-
-static int dwc3_qcom_probe(struct platform_device *pdev)
-{
-	struct device_node *node = pdev->dev.of_node;
-	struct dwc3_qcom *qdwc;
-	int ret;
-
-	qdwc = devm_kzalloc(&pdev->dev, sizeof(*qdwc), GFP_KERNEL);
-	if (!qdwc)
-		return -ENOMEM;
-
-	platform_set_drvdata(pdev, qdwc);
-
-	qdwc->dev = &pdev->dev;
-
-	qdwc->core_clk = devm_clk_get(qdwc->dev, "core");
-	if (IS_ERR(qdwc->core_clk)) {
-		dev_err(qdwc->dev, "failed to get core clock\n");
-		return PTR_ERR(qdwc->core_clk);
-	}
-
-	qdwc->iface_clk = devm_clk_get(qdwc->dev, "iface");
-	if (IS_ERR(qdwc->iface_clk)) {
-		dev_info(qdwc->dev, "failed to get optional iface clock\n");
-		qdwc->iface_clk = NULL;
-	}
-
-	qdwc->sleep_clk = devm_clk_get(qdwc->dev, "sleep");
-	if (IS_ERR(qdwc->sleep_clk)) {
-		dev_info(qdwc->dev, "failed to get optional sleep clock\n");
-		qdwc->sleep_clk = NULL;
-	}
-
-	ret = clk_prepare_enable(qdwc->core_clk);
-	if (ret) {
-		dev_err(qdwc->dev, "failed to enable core clock\n");
-		goto err_core;
-	}
-
-	ret = clk_prepare_enable(qdwc->iface_clk);
-	if (ret) {
-		dev_err(qdwc->dev, "failed to enable optional iface clock\n");
-		goto err_iface;
-	}
-
-	ret = clk_prepare_enable(qdwc->sleep_clk);
-	if (ret) {
-		dev_err(qdwc->dev, "failed to enable optional sleep clock\n");
-		goto err_sleep;
-	}
-
-	ret = of_platform_populate(node, NULL, NULL, qdwc->dev);
-	if (ret) {
-		dev_err(qdwc->dev, "failed to register core - %d\n", ret);
-		goto err_clks;
-	}
-
-	return 0;
-
-err_clks:
-	clk_disable_unprepare(qdwc->sleep_clk);
-err_sleep:
-	clk_disable_unprepare(qdwc->iface_clk);
-err_iface:
-	clk_disable_unprepare(qdwc->core_clk);
-err_core:
-	return ret;
-}
-
-static int dwc3_qcom_remove(struct platform_device *pdev)
-{
-	struct dwc3_qcom *qdwc = platform_get_drvdata(pdev);
-
-	of_platform_depopulate(&pdev->dev);
-
-	clk_disable_unprepare(qdwc->sleep_clk);
-	clk_disable_unprepare(qdwc->iface_clk);
-	clk_disable_unprepare(qdwc->core_clk);
-
-	return 0;
-}
-
-static const struct of_device_id of_dwc3_match[] = {
-	{ .compatible = "qcom,dwc3" },
-	{ /* Sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, of_dwc3_match);
-
-static struct platform_driver dwc3_qcom_driver = {
-	.probe		= dwc3_qcom_probe,
-	.remove		= dwc3_qcom_remove,
-	.driver		= {
-		.name	= "qcom-dwc3",
-		.of_match_table	= of_dwc3_match,
-	},
-};
-
-module_platform_driver(dwc3_qcom_driver);
-
-MODULE_ALIAS("platform:qcom-dwc3");
-MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("DesignWare USB3 QCOM Glue Layer");
-MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index b13912d5f..8d6b75c2f 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -812,6 +812,8 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 
 	status = DWC3_TRB_SIZE_TRBSTS(trb->size);
 	if (status == DWC3_TRBSTS_SETUP_PENDING) {
+		dwc->setup_packet_pending = true;
+
 		dwc3_trace(trace_dwc3_ep0, "Setup Pending received");
 
 		if (r)
@@ -911,8 +913,10 @@ static void dwc3_ep0_complete_status(struct dwc3 *dwc,
 	}
 
 	status = DWC3_TRB_SIZE_TRBSTS(trb->size);
-	if (status == DWC3_TRBSTS_SETUP_PENDING)
+	if (status == DWC3_TRBSTS_SETUP_PENDING) {
+		dwc->setup_packet_pending = true;
 		dwc3_trace(trace_dwc3_ep0, "Setup Pending received");
+	}
 
 	dwc->ep0state = EP0_SETUP_PHASE;
 	dwc3_ep0_out_start(dwc);
@@ -966,7 +970,7 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 		ret = usb_gadget_map_request(&dwc->gadget, &req->request,
 				dep->number);
 		if (ret) {
-			dev_dbg(dwc->dev, "failed to map request\n");
+			dwc3_trace(trace_dwc3_ep0, "failed to map request\n");
 			return;
 		}
 
@@ -994,7 +998,7 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 		ret = usb_gadget_map_request(&dwc->gadget, &req->request,
 				dep->number);
 		if (ret) {
-			dev_dbg(dwc->dev, "failed to map request\n");
+			dwc3_trace(trace_dwc3_ep0, "failed to map request\n");
 			return;
 		}
 
@@ -1058,8 +1062,6 @@ static void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
 static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 		const struct dwc3_event_depevt *event)
 {
-	dwc->setup_packet_pending = true;
-
 	switch (event->status) {
 	case DEPEVT_STATUS_CONTROL_DATA:
 		dwc3_trace(trace_dwc3_ep0, "Control Data");
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 69ffe6e8d..2363bad45 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -265,9 +265,6 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		usb_gadget_unmap_request(&dwc->gadget, &req->request,
 				req->direction);
 
-	dev_dbg(dwc->dev, "request %p from %s completed %d/%d ===> %d\n",
-			req, dep->name, req->request.actual,
-			req->request.length, status);
 	trace_dwc3_gadget_giveback(req);
 
 	spin_unlock(&dwc->lock);
@@ -702,11 +699,10 @@ static int dwc3_gadget_ep_enable(struct usb_ep *ep,
 	dep = to_dwc3_ep(ep);
 	dwc = dep->dwc;
 
-	if (dep->flags & DWC3_EP_ENABLED) {
-		dev_WARN_ONCE(dwc->dev, true, "%s is already enabled\n",
-				dep->name);
+	if (dev_WARN_ONCE(dwc->dev, dep->flags & DWC3_EP_ENABLED,
+					"%s is already enabled\n",
+					dep->name))
 		return 0;
-	}
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	ret = __dwc3_gadget_ep_enable(dep, desc, ep->comp_desc, false, false);
@@ -730,11 +726,10 @@ static int dwc3_gadget_ep_disable(struct usb_ep *ep)
 	dep = to_dwc3_ep(ep);
 	dwc = dep->dwc;
 
-	if (!(dep->flags & DWC3_EP_ENABLED)) {
-		dev_WARN_ONCE(dwc->dev, true, "%s is already disabled\n",
-				dep->name);
+	if (dev_WARN_ONCE(dwc->dev, !(dep->flags & DWC3_EP_ENABLED),
+					"%s is already disabled\n",
+					dep->name))
 		return 0;
-	}
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	ret = __dwc3_gadget_ep_disable(dep);
@@ -1023,8 +1018,6 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
 	cmd |= DWC3_DEPCMD_PARAM(cmd_param);
 	ret = dwc3_send_gadget_ep_cmd(dwc, dep->number, cmd, &params);
 	if (ret < 0) {
-		dev_dbg(dwc->dev, "failed to send STARTTRANSFER command\n");
-
 		/*
 		 * FIXME we need to iterate over the list of requests
 		 * here and stop, unmap, free and del each of the linked
@@ -1082,6 +1075,20 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 	struct dwc3		*dwc = dep->dwc;
 	int			ret;
 
+	if (!dep->endpoint.desc) {
+		dwc3_trace(trace_dwc3_gadget,
+				"trying to queue request %p to disabled %s\n",
+				&req->request, dep->endpoint.name);
+		return -ESHUTDOWN;
+	}
+
+	if (WARN(req->dep != dep, "request %p belongs to '%s'\n",
+				&req->request, req->dep->name)) {
+		dwc3_trace(trace_dwc3_gadget, "request %p belongs to '%s'\n",
+				&req->request, req->dep->name);
+		return -EINVAL;
+	}
+
 	req->request.actual	= 0;
 	req->request.status	= -EINPROGRESS;
 	req->direction		= dep->direction;
@@ -1179,7 +1186,8 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 
 out:
 	if (ret && ret != -EBUSY)
-		dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
+		dwc3_trace(trace_dwc3_gadget,
+				"%s: failed to kick transfers\n",
 				dep->name);
 	if (ret == -EBUSY)
 		ret = 0;
@@ -1187,6 +1195,32 @@ out:
 	return ret;
 }
 
+static void __dwc3_gadget_ep_zlp_complete(struct usb_ep *ep,
+		struct usb_request *request)
+{
+	dwc3_gadget_ep_free_request(ep, request);
+}
+
+static int __dwc3_gadget_ep_queue_zlp(struct dwc3 *dwc, struct dwc3_ep *dep)
+{
+	struct dwc3_request		*req;
+	struct usb_request		*request;
+	struct usb_ep			*ep = &dep->endpoint;
+
+	dwc3_trace(trace_dwc3_gadget, "queueing ZLP\n");
+	request = dwc3_gadget_ep_alloc_request(ep, GFP_ATOMIC);
+	if (!request)
+		return -ENOMEM;
+
+	request->length = 0;
+	request->buf = dwc->zlp_buf;
+	request->complete = __dwc3_gadget_ep_zlp_complete;
+
+	req = to_dwc3_request(request);
+
+	return __dwc3_gadget_ep_queue(dep, req);
+}
+
 static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
 	gfp_t gfp_flags)
 {
@@ -1199,22 +1233,18 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
 	int				ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
-	if (!dep->endpoint.desc) {
-		dev_dbg(dwc->dev, "trying to queue request %p to disabled %s\n",
-				request, ep->name);
-		ret = -ESHUTDOWN;
-		goto out;
-	}
-
-	if (WARN(req->dep != dep, "request %p belongs to '%s'\n",
-				request, req->dep->name)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	ret = __dwc3_gadget_ep_queue(dep, req);
 
-out:
+	/*
+	 * Okay, here's the thing, if gadget driver has requested for a ZLP by
+	 * setting request->zero, instead of doing magic, we will just queue an
+	 * extra usb_request ourselves so that it gets handled the same way as
+	 * any other request.
+	 */
+	if (ret == 0 && request->zero && request->length &&
+	    (request->length % ep->maxpacket == 0))
+		ret = __dwc3_gadget_ep_queue_zlp(dwc, dep);
+
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	return ret;
@@ -1284,7 +1314,8 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
 		if (!protocol && ((dep->direction && dep->flags & DWC3_EP_BUSY) ||
 				(!list_empty(&dep->req_queued) ||
 				 !list_empty(&dep->request_list)))) {
-			dev_dbg(dwc->dev, "%s: pending request, cannot halt\n",
+			dwc3_trace(trace_dwc3_gadget,
+					"%s: pending request, cannot halt\n",
 					dep->name);
 			return -EAGAIN;
 		}
@@ -1411,7 +1442,7 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
 
 	speed = reg & DWC3_DSTS_CONNECTSPD;
 	if (speed == DWC3_DSTS_SUPERSPEED) {
-		dev_dbg(dwc->dev, "no wakeup on SuperSpeed\n");
+		dwc3_trace(trace_dwc3_gadget, "no wakeup on SuperSpeed\n");
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1423,8 +1454,9 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
 	case DWC3_LINK_STATE_U3:	/* in HS, means SUSPEND */
 		break;
 	default:
-		dev_dbg(dwc->dev, "can't wakeup from link state %d\n",
-				link_state);
+		dwc3_trace(trace_dwc3_gadget,
+				"can't wakeup from '%s'\n",
+				dwc3_gadget_link_string(link_state));
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1861,7 +1893,8 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 		if (count) {
 			trb_status = DWC3_TRB_SIZE_TRBSTS(trb->size);
 			if (trb_status == DWC3_TRBSTS_MISSED_ISOC) {
-				dev_dbg(dwc->dev, "incomplete IN transfer %s\n",
+				dwc3_trace(trace_dwc3_gadget,
+						"%s: incomplete IN transfer\n",
 						dep->name);
 				/*
 				 * If missed isoc occurred and there is
@@ -1923,10 +1956,9 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 
 	do {
 		req = next_request(&dep->req_queued);
-		if (!req) {
-			WARN_ON_ONCE(1);
+		if (WARN_ON_ONCE(!req))
 			return 1;
-		}
+
 		i = 0;
 		do {
 			slot = req->start_slot + i;
@@ -2040,7 +2072,8 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		dep->resource_index = 0;
 
 		if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-			dev_dbg(dwc->dev, "%s is an Isochronous endpoint\n",
+			dwc3_trace(trace_dwc3_gadget,
+					"%s is an Isochronous endpoint\n",
 					dep->name);
 			return;
 		}
@@ -2067,7 +2100,8 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 			if (!ret || ret == -EBUSY)
 				return;
 
-			dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
+			dwc3_trace(trace_dwc3_gadget,
+					"%s: failed to kick transfers\n",
 					dep->name);
 		}
 
@@ -2089,11 +2123,12 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		case DEPEVT_STREAMEVT_NOTFOUND:
 			/* FALLTHROUGH */
 		default:
-			dev_dbg(dwc->dev, "Couldn't find suitable stream\n");
+			dwc3_trace(trace_dwc3_gadget,
+					"unable to find suitable stream\n");
 		}
 		break;
 	case DWC3_DEPEVT_RXTXFIFOEVT:
-		dev_dbg(dwc->dev, "%s FIFO Overrun\n", dep->name);
+		dwc3_trace(trace_dwc3_gadget, "%s FIFO Overrun\n", dep->name);
 		break;
 	case DWC3_DEPEVT_EPCMDCMPLT:
 		dwc3_trace(trace_dwc3_gadget, "Endpoint Command Complete");
@@ -2265,8 +2300,8 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 	 *
 	 * Our suggested workaround is to follow the Disconnect
 	 * Event steps here, instead, based on a setup_packet_pending
-	 * flag. Such flag gets set whenever we have a XferNotReady
-	 * event on EP0 and gets cleared on XferComplete for the
+	 * flag. Such flag gets set whenever we have a SETUP_PENDING
+	 * status for EP0 TRBs and gets cleared on XferComplete for the
 	 * same endpoint.
 	 *
 	 * Refers to:
@@ -2778,10 +2813,17 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 		goto err3;
 	}
 
+	dwc->zlp_buf = kzalloc(DWC3_ZLP_BUF_SIZE, GFP_KERNEL);
+	if (!dwc->zlp_buf) {
+		ret = -ENOMEM;
+		goto err4;
+	}
+
 	dwc->gadget.ops			= &dwc3_gadget_ops;
 	dwc->gadget.speed		= USB_SPEED_UNKNOWN;
 	dwc->gadget.sg_supported	= true;
 	dwc->gadget.name		= "dwc3-gadget";
+	dwc->gadget.is_otg		= dwc->dr_mode == USB_DR_MODE_OTG;
 
 	/*
 	 * FIXME We might be setting max_speed to <SUPER, however versions
@@ -2819,16 +2861,19 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 
 	ret = dwc3_gadget_init_endpoints(dwc);
 	if (ret)
-		goto err4;
+		goto err5;
 
 	ret = usb_add_gadget_udc(dwc->dev, &dwc->gadget);
 	if (ret) {
 		dev_err(dwc->dev, "failed to register udc\n");
-		goto err4;
+		goto err5;
 	}
 
 	return 0;
 
+err5:
+	kfree(dwc->zlp_buf);
+
 err4:
 	dwc3_gadget_free_endpoints(dwc);
 	dma_free_coherent(dwc->dev, DWC3_EP0_BOUNCE_SIZE,
@@ -2861,6 +2906,7 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 			dwc->ep0_bounce, dwc->ep0_bounce_addr);
 
 	kfree(dwc->setup_buf);
+	kfree(dwc->zlp_buf);
 
 	dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb),
 			dwc->ep0_trb, dwc->ep0_trb_addr);
diff --git a/drivers/usb/dwc3/trace.h b/drivers/usb/dwc3/trace.h
index 9c10669ab..3ac7252f4 100644
--- a/drivers/usb/dwc3/trace.h
+++ b/drivers/usb/dwc3/trace.h
@@ -117,6 +117,9 @@ DECLARE_EVENT_CLASS(dwc3_log_request,
 		__field(unsigned, actual)
 		__field(unsigned, length)
 		__field(int, status)
+		__field(int, zero)
+		__field(int, short_not_ok)
+		__field(int, no_interrupt)
 	),
 	TP_fast_assign(
 		snprintf(__get_str(name), DWC3_MSG_MAX, "%s", req->dep->name);
@@ -124,9 +127,15 @@ DECLARE_EVENT_CLASS(dwc3_log_request,
 		__entry->actual = req->request.actual;
 		__entry->length = req->request.length;
 		__entry->status = req->request.status;
+		__entry->zero = req->request.zero;
+		__entry->short_not_ok = req->request.short_not_ok;
+		__entry->no_interrupt = req->request.no_interrupt;
 	),
-	TP_printk("%s: req %p length %u/%u ==> %d",
+	TP_printk("%s: req %p length %u/%u %s%s%s ==> %d",
 		__get_str(name), __entry->req, __entry->actual, __entry->length,
+		__entry->zero ? "Z" : "z",
+		__entry->short_not_ok ? "S" : "s",
+		__entry->no_interrupt ? "i" : "I",
 		__entry->status
 	)
 );