This patch introduce new Cadence USBSS DRD driver to linux kernel.

The Cadence USBSS DRD Driver is a highly configurable IP Core whichi
can be instantiated as Dual-Role Device (DRD), Peripheral Only and
Host Only (XHCI)configurations.

The current driver has been validated with FPGA burned. We have support
for PCIe bus, which is used on FPGA prototyping.

The host side of USBSS-DRD controller is compliance with XHCI
specification, so it works with standard XHCI linux driver.

Signed-off-by: Pawel Laszczak <pawell@cadence.com>
---
 drivers/usb/Kconfig                |    2 +
 drivers/usb/Makefile               |    2 +
 drivers/usb/cdns3/Kconfig          |   44 +
 drivers/usb/cdns3/Makefile         |   14 +
 drivers/usb/cdns3/cdns3-pci-wrap.c |  155 +++
 drivers/usb/cdns3/core.c           |  403 ++++++
 drivers/usb/cdns3/core.h           |  116 ++
 drivers/usb/cdns3/debug.h          |  168 +++
 drivers/usb/cdns3/debugfs.c        |  164 +++
 drivers/usb/cdns3/drd.c            |  365 +++++
 drivers/usb/cdns3/drd.h            |  162 +++
 drivers/usb/cdns3/ep0.c            |  907 +++++++++++++
 drivers/usb/cdns3/gadget-export.h  |   28 +
 drivers/usb/cdns3/gadget.c         | 2003 ++++++++++++++++++++++++++++
 drivers/usb/cdns3/gadget.h         | 1207 +++++++++++++++++
 drivers/usb/cdns3/host-export.h    |   28 +
 drivers/usb/cdns3/host.c           |   72 +
 drivers/usb/cdns3/trace.c          |   23 +
 drivers/usb/cdns3/trace.h          |  404 ++++++
 19 files changed, 6267 insertions(+)
 create mode 100644 drivers/usb/cdns3/Kconfig
 create mode 100644 drivers/usb/cdns3/Makefile
 create mode 100644 drivers/usb/cdns3/cdns3-pci-wrap.c
 create mode 100644 drivers/usb/cdns3/core.c
 create mode 100644 drivers/usb/cdns3/core.h
 create mode 100644 drivers/usb/cdns3/debug.h
 create mode 100644 drivers/usb/cdns3/debugfs.c
 create mode 100644 drivers/usb/cdns3/drd.c
 create mode 100644 drivers/usb/cdns3/drd.h
 create mode 100644 drivers/usb/cdns3/ep0.c
 create mode 100644 drivers/usb/cdns3/gadget-export.h
 create mode 100644 drivers/usb/cdns3/gadget.c
 create mode 100644 drivers/usb/cdns3/gadget.h
 create mode 100644 drivers/usb/cdns3/host-export.h
 create mode 100644 drivers/usb/cdns3/host.c
 create mode 100644 drivers/usb/cdns3/trace.c
 create mode 100644 drivers/usb/cdns3/trace.h

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 987fc5ba6321..5f9334019d04 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig

@@ -112,6 +112,8 @@ source "drivers/usb/usbip/Kconfig"
 
 endif
 
+source "drivers/usb/cdns3/Kconfig"
+
 source "drivers/usb/mtu3/Kconfig"
 
 source "drivers/usb/musb/Kconfig"

diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
index 7d1b8c82b208..ab125b966cac 100644
--- a/drivers/usb/Makefile
+++ b/drivers/usb/Makefile

@@ -12,6 +12,8 @@ obj-$(CONFIG_USB_DWC3)		+= dwc3/
 obj-$(CONFIG_USB_DWC2)		+= dwc2/
 obj-$(CONFIG_USB_ISP1760)	+= isp1760/
 
+obj-$(CONFIG_USB_CDNS3)		+= cdns3/
+
 obj-$(CONFIG_USB_MON)		+= mon/
 obj-$(CONFIG_USB_MTU3)		+= mtu3/
 

diff --git a/drivers/usb/cdns3/Kconfig b/drivers/usb/cdns3/Kconfig
new file mode 100644
index 000000000000..27cb3d8dbe3d
--- /dev/null
+++ b/drivers/usb/cdns3/Kconfig

@@ -0,0 +1,44 @@
+config USB_CDNS3
+	tristate "Cadence USB3 Dual-Role Controller"
+	depends on USB_SUPPORT && (USB || USB_GADGET) && HAS_DMA
+	help
+	  Say Y here if your system has a cadence USB3 dual-role controller.
+	  It supports: dual-role switch, Host-only, and Peripheral-only.
+
+	  If you choose to build this driver is a dynamically linked
+	  as module, the module will be called cdns3.ko.
+
+if USB_CDNS3
+
+config USB_CDNS3_GADGET
+        bool "Cadence USB3 device controller"
+        depends on USB_GADGET
+        help
+          Say Y here to enable device controller functionality of the
+          cadence USBSS-DEV driver.

+
+          This controller supports FF, HS and SS mode. It doesn't support
+          LS and SSP mode.
+
+config USB_CDNS3_HOST
+        bool "Cadence USB3 host controller"
+        depends on USB_XHCI_HCD
+        help
+          Say Y here to enable host controller functionality of the
+          cadence driver.
+
+          Host controller is compliant with XHCI so it will use
+          standard XHCI driver.
+
+config USB_CDNS3_PCI_WRAP
+	tristate "Cadence USB3 support on PCIe-based platforms"
+	depends on USB_PCI && ACPI
+	default USB_CDNS3
+	help
+	  If you're using the USBSS Core IP with a PCIe, please say
+	  'Y' or 'M' here.
+
+	  If you choose to build this driver as module it will
+	  be dynamically linked and module will be called cdns3-pci.ko
+
+endif

diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
new file mode 100644
index 000000000000..8f9438593375
--- /dev/null
+++ b/drivers/usb/cdns3/Makefile

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+# define_trace.h needs to know how to find our header
+CFLAGS_trace.o				:= -I$(src)
+
+cdns3-y					:= core.o drd.o trace.o
+
+obj-$(CONFIG_USB_CDNS3)			+= cdns3.o
+ifneq ($(CONFIG_DEBUG_FS),)
+	cdns3-y				+= debugfs.o
+endif
+
+cdns3-$(CONFIG_USB_CDNS3_GADGET)	+= gadget.o ep0.o
+cdns3-$(CONFIG_USB_CDNS3_HOST)		+= host.o
+obj-$(CONFIG_USB_CDNS3_PCI_WRAP)	+= cdns3-pci-wrap.o

diff --git a/drivers/usb/cdns3/cdns3-pci-wrap.c b/drivers/usb/cdns3/cdns3-pci-wrap.c
new file mode 100644
index 000000000000..d0b2d3d9b983
--- /dev/null
+++ b/drivers/usb/cdns3/cdns3-pci-wrap.c

@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS PCI Glue driver
+ *
+ * Copyright (C) 2018 Cadence.

+ *
+ * Author: Pawel Laszczak [off-list ref]
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+
+struct cdns3_wrap {
+	struct platform_device *plat_dev;
+	struct pci_dev *hg_dev;
+	struct resource dev_res[4];
+};
+
+struct cdns3_wrap wrap;
+
+#define RES_IRQ_ID		0
+#define RES_HOST_ID		1
+#define RES_DEV_ID		2
+#define RES_DRD_ID		3
+
+#define PCI_BAR_HOST		0
+#define PCI_BAR_DEV		2
+#define PCI_BAR_OTG		4
+
+#define PCI_DEV_FN_HOST_DEVICE	0
+#define PCI_DEV_FN_OTG		1
+
+#define PCI_DRIVER_NAME		"cdns3-pci-usbss"
+#define PLAT_DRIVER_NAME	"cdns-usb3"
+
+#define CDNS_VENDOR_ID 0x17cd
+#define CDNS_DEVICE_ID 0x0100
+
+/**
+ * cdns3_pci_probe - Probe function for Cadence USB wrapper driver
+ * @pdev: platform device object
+ * @id: pci device id
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_pci_probe(struct pci_dev *pdev,
+			   const struct pci_device_id *id)
+{
+	struct platform_device_info plat_info;
+	struct cdns3_wrap *wrap;
+	struct resource *res;
+	int err;
+
+	/*
+	 * for GADGET/HOST PCI (devfn) function number is 0,
+	 * for OTG PCI (devfn) function number is 1
+	 */
+	if (!id || pdev->devfn != PCI_DEV_FN_HOST_DEVICE)
+		return -EINVAL;
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "Enabling PCI device has failed %d\n", err);
+		return err;
+	}
+
+	pci_set_master(pdev);
+	wrap = devm_kzalloc(&pdev->dev, sizeof(*wrap), GFP_KERNEL);
+	if (!wrap) {
+		dev_err(&pdev->dev, "Failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	/* function 0: host(BAR_0) + device(BAR_1) + otg(BAR_2)). */
+	memset(wrap->dev_res, 0x00,
+	       sizeof(struct resource) * ARRAY_SIZE(wrap->dev_res));
+	dev_dbg(&pdev->dev, "Initialize Device resources\n");
+	res = wrap->dev_res;
+
+	res[RES_DEV_ID].start = pci_resource_start(pdev, PCI_BAR_DEV);
+	res[RES_DEV_ID].end =   pci_resource_end(pdev, PCI_BAR_DEV);
+	res[RES_DEV_ID].name = "dev";
+	res[RES_DEV_ID].flags = IORESOURCE_MEM;
+	dev_dbg(&pdev->dev, "USBSS-DEV physical base addr: %pa\n",
+		&res[RES_DEV_ID].start);
+
+	res[RES_HOST_ID].start = pci_resource_start(pdev, PCI_BAR_HOST);
+	res[RES_HOST_ID].end = pci_resource_end(pdev, PCI_BAR_HOST);
+	res[RES_HOST_ID].name = "xhci";
+	res[RES_HOST_ID].flags = IORESOURCE_MEM;
+	dev_dbg(&pdev->dev, "USBSS-XHCI physical base addr: %pa\n",
+		&res[RES_HOST_ID].start);
+
+	res[RES_DRD_ID].start = pci_resource_start(pdev, PCI_BAR_OTG);
+	res[RES_DRD_ID].end =   pci_resource_end(pdev, PCI_BAR_OTG);
+	res[RES_DRD_ID].name = "otg";
+	res[RES_DRD_ID].flags = IORESOURCE_MEM;
+	dev_dbg(&pdev->dev, "USBSS-DRD physical base addr: %pa\n",
+		&res[RES_DRD_ID].start);
+
+	/* Interrupt common for both device and XHCI */
+	wrap->dev_res[RES_IRQ_ID].start = pdev->irq;
+	wrap->dev_res[RES_IRQ_ID].name = "cdns3-irq";
+	wrap->dev_res[RES_IRQ_ID].flags = IORESOURCE_IRQ;
+
+	/* set up platform device info */
+	memset(&plat_info, 0, sizeof(plat_info));
+	plat_info.parent = &pdev->dev;
+	plat_info.fwnode = pdev->dev.fwnode;
+	plat_info.name = PLAT_DRIVER_NAME;
+	plat_info.id = pdev->devfn;
+	plat_info.res = wrap->dev_res;
+	plat_info.num_res = ARRAY_SIZE(wrap->dev_res);
+	plat_info.dma_mask = pdev->dma_mask;
+
+	/* register platform device */
+	wrap->plat_dev = platform_device_register_full(&plat_info);
+	if (IS_ERR(wrap->plat_dev))
+		return PTR_ERR(wrap->plat_dev);
+
+	pci_set_drvdata(pdev, wrap);
+
+	return err;
+}
+
+void cdns3_pci_remove(struct pci_dev *pdev)
+{
+	struct cdns3_wrap *wrap = (struct cdns3_wrap *)pci_get_drvdata(pdev);
+
+	platform_device_unregister(wrap->plat_dev);
+}
+
+static const struct pci_device_id cdns3_pci_ids[] = {
+	{ PCI_DEVICE(CDNS_VENDOR_ID, CDNS_DEVICE_ID), },
+	{ 0, }
+};
+
+static struct pci_driver cdns3_pci_driver = {
+	.name = PCI_DRIVER_NAME,
+	.id_table = cdns3_pci_ids,
+	.probe = cdns3_pci_probe,
+	.remove = cdns3_pci_remove,
+};
+
+module_pci_driver(cdns3_pci_driver);
+MODULE_DEVICE_TABLE(pci, cdns3_pci_ids);
+
+MODULE_AUTHOR("Pawel Laszczak [off-list ref]");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USBSS PCI wrapperr");
+

diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
new file mode 100644
index 000000000000..aa2f63241dab
--- /dev/null
+++ b/drivers/usb/cdns3/core.c

@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2018 Cadence.
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Author: Peter Chen <peter.chen@nxp.com>
+ *         Pawel Laszczak <pawell@cadence.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/pm_runtime.h>
+
+#include "gadget.h"
+#include "core.h"
+#include "host-export.h"
+#include "gadget-export.h"
+#include "drd.h"
+#include "debug.h"
+
+static inline
+struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
+{
+	WARN_ON(cdns->role >= CDNS3_ROLE_END || !cdns->roles[cdns->role]);
+	return cdns->roles[cdns->role];
+}
+
+static int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
+{
+	int ret;
+
+	if (WARN_ON(role >= CDNS3_ROLE_END))
+		return 0;
+
+	if (!cdns->roles[role])
+		return -ENXIO;
+
+	if (cdns->roles[role]->state == CDNS3_ROLE_STATE_ACTIVE)
+		return 0;
+
+	mutex_lock(&cdns->mutex);
+	cdns->role = role;
+	ret = cdns->roles[role]->start(cdns);
+	if (!ret)
+		cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
+	mutex_unlock(&cdns->mutex);
+	return ret;
+}
+
+void cdns3_role_stop(struct cdns3 *cdns)
+{
+	enum cdns3_roles role = cdns->role;
+
+	if (role >= CDNS3_ROLE_END) {
+		WARN_ON(role > CDNS3_ROLE_END);
+		return;
+	}
+
+	if (cdns->roles[role]->state == CDNS3_ROLE_STATE_INACTIVE)
+		return;
+
+	mutex_lock(&cdns->mutex);
+	cdns->roles[role]->stop(cdns);
+	cdns->roles[role]->state = CDNS3_ROLE_STATE_INACTIVE;
+	mutex_unlock(&cdns->mutex);
+}
+
+/*
+ * cdns->role gets from cdns3_get_initial_role, and this API tells role at the
+ * runtime.
+ * If both roles are supported, the role is selected based on vbus/id.
+ * It could be read from OTG register or external connector.
+ * If only single role is supported, only one role structure
+ * is allocated, cdns->roles[CDNS3_ROLE_HOST] or cdns->roles[CDNS3_ROLE_GADGET].
+ */
+static enum cdns3_roles cdns3_get_initial_role(struct cdns3 *cdns)
+{
+	if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) {
+		if (cdns3_is_host(cdns))
+			return CDNS3_ROLE_HOST;
+		if (cdns3_is_device(cdns))
+			return CDNS3_ROLE_GADGET;
+	}
+	return cdns->roles[CDNS3_ROLE_HOST]
+		? CDNS3_ROLE_HOST
+		: CDNS3_ROLE_GADGET;
+}
+
+static void cdns3_exit_roles(struct cdns3 *cdns)
+{
+	cdns3_role_stop(cdns);
+	cdns3_drd_exit(cdns);
+}
+
+/**
+ * cdns3_core_init_role - initialize role of operation
+ * @cdns: Pointer to cdns3 structure
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_core_init_role(struct cdns3 *cdns)
+{
+	struct device *dev = cdns->dev;
+	enum usb_dr_mode best_dr_mode;
+	enum usb_dr_mode dr_mode;
+	int ret = 0;
+
+	dr_mode = usb_get_dr_mode(dev);
+	cdns->role = CDNS3_ROLE_END;
+
+	/*
+	 * If driver can't read mode by means of usb_get_dr_mdoe function then

+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_cdns3_match[] = {
+	{ .compatible = "cdns,usb3-1.0.0" },
+	{ .compatible = "cdns,usb3-1.0.1" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, of_cdns3_match);
+#endif
+
+static struct platform_driver cdns3_driver = {
+	.probe		= cdns3_probe,
+	.remove		= cdns3_remove,
+	.driver		= {
+		.name	= "cdns-usb3",
+		.of_match_table	= of_match_ptr(of_cdns3_match),
+	},
+};
+
+module_platform_driver(cdns3_driver);
+
+MODULE_ALIAS("platform:cdns3");
+MODULE_AUTHOR("Pawel Laszczak [off-list ref]");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");

diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
new file mode 100644
index 000000000000..fb4b39206158
--- /dev/null
+++ b/drivers/usb/cdns3/core.h

@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Header File.
+ *
+ * Copyright (C) 2017-2018 NXP
+ * Copyright (C) 2018 Cadence.
+ *
+ * Authors: Peter Chen <peter.chen@nxp.com>
+ *          Pawel Laszczak <pawell@cadence.com>
+ */
+#include <linux/usb/otg.h>
+
+#ifndef __LINUX_CDNS3_CORE_H
+#define __LINUX_CDNS3_CORE_H
+
+struct cdns3;
+enum cdns3_roles {
+	CDNS3_ROLE_HOST = 0,
+	CDNS3_ROLE_GADGET,
+	CDNS3_ROLE_END,
+};
+
+/**
+ * struct cdns3_role_driver - host/gadget role driver
+ * @start: start this role
+ * @stop: stop this role
+ * @suspend: suspend callback for this role
+ * @resume: resume callback for this role
+ * @irq: irq handler for this role
+ * @name: role name string (host/gadget)
+ * @state: current state
+ */
+struct cdns3_role_driver {
+	int (*start)(struct cdns3 *cdns);
+	void (*stop)(struct cdns3 *cdns);
+	int (*suspend)(struct cdns3 *cdns, bool do_wakeup);
+	int (*resume)(struct cdns3 *cdns, bool hibernated);
+	const char *name;
+#define CDNS3_ROLE_STATE_INACTIVE	0
+#define CDNS3_ROLE_STATE_ACTIVE		1
+	int state;
+};
+
+#define CDNS3_XHCI_RESOURCES_NUM	2
+/**
+ * struct cdns3 - Representation of Cadence USB3 DRD controller.
+ * @dev: pointer to Cadence device struct
+ * @xhci_regs: pointer to base of xhci registers
+ * @xhci_res: the resource for xhci
+ * @dev_regs: pointer to base of dev registers
+ * @otg_regs: pointer to base of otg registers
+ * @irq: irq number for controller
+ * @roles: array of supported roles for this controller
+ * @role: current role
+ * @host_dev: the child host device pointer for cdns3 core
+ * @gadget_dev: the child gadget device pointer for cdns3 core
+ * @usb: phy for this controller
+ * @role_switch_wq: work queue item for role switch
+ * @in_lpm: the controller in low power mode
+ * @wakeup_int: the wakeup interrupt
+ * @mutex: the mutex for concurrent code at driver
+ * @dr_mode: supported mode of operation it can be only Host, only Device
+ *           or OTG mode that allow to switch between Device and Host mode.
+ *           This field based on firmware setting, kernel configuration
+ *           and hardware configuration.
+ * @current_dr_mode: current mode of operation when in dual-role mode
+ * @desired_dr_mode: desired mode of operation when in dual-role mode.
+ *           This value can be changed during runtime.
+ *           Available options depends on  dr_mode:
+ *           dr_mode                 |  desired_dr_mode and current_dr_mode
+ *           ----------------------------------------------------------------
+ *           USB_DR_MODE_HOST        | only USB_DR_MODE_HOST
+ *           USB_DR_MODE_PERIPHERAL  | only USB_DR_MODE_PERIPHERAL
+ *           USB_DR_MODE_OTG         | only USB_DR_MODE_HOST
+ *           USB_DR_MODE_OTG         | only USB_DR_MODE_PERIPHERAL
+ *           USB_DR_MODE_OTG         | USB_DR_MODE_OTG

+ *
+ *           Desired_dr_role can be changed by means of debugfs.
+ * @root: debugfs root folder pointer
+ * @debug_disable:
+ */
+struct cdns3 {
+	struct device			*dev;
+	void __iomem			*xhci_regs;
+	struct resource			xhci_res[CDNS3_XHCI_RESOURCES_NUM];
+	struct cdns3_usb_regs __iomem	*dev_regs;
+
+	struct resource			otg_res;
+	struct cdns3_otg_legacy_regs	*otg_v0_regs;
+	struct cdns3_otg_regs		*otg_v1_regs;
+	struct cdns3_otg_common_regs	*otg_regs;
+#define CDNS3_CONTROLLER_V0	0
+#define CDNS3_CONTROLLER_V1	1
+	u32				version;
+
+	int				irq;
+	struct cdns3_role_driver	*roles[CDNS3_ROLE_END];
+	enum cdns3_roles		role;
+	struct platform_device		*host_dev;
+	struct cdns3_device		*gadget_dev;
+	struct phy			*phy;
+	struct work_struct		role_switch_wq;
+	int				in_lpm:1;
+	int				wakeup_int:1;
+	/* mutext used in workqueue*/
+	struct mutex			mutex;
+	enum usb_dr_mode		dr_mode;
+	enum usb_dr_mode		current_dr_mode;
+	enum usb_dr_mode		desired_dr_mode;
+	struct dentry			*root;
+	int				debug_disable:1;
+};
+
+void cdns3_role_stop(struct cdns3 *cdns);
+
+#endif /* __LINUX_CDNS3_CORE_H */

diff --git a/drivers/usb/cdns3/debug.h b/drivers/usb/cdns3/debug.h
new file mode 100644
index 000000000000..1929edb3a521
--- /dev/null
+++ b/drivers/usb/cdns3/debug.h

@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Driver.
+ * Debug header file.
+ *
+ * Copyright (C) 2018 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+#ifndef __LINUX_CDNS3_DEBUG
+#define __LINUX_CDNS3_DEBUG
+
+#include "core.h"
+
+static inline char *cdns3_decode_usb_irq(char *str,
+					 enum usb_device_speed speed,
+					 u32 usb_ists)
+{
+	int ret;
+
+	ret = sprintf(str, "IRQ %08x = ", usb_ists);
+
+	if (usb_ists & (USB_ISTS_CON2I | USB_ISTS_CONI)) {
+		ret += sprintf(str + ret, "Connection %s\n",
+			       usb_speed_string(speed));
+	}
+	if (usb_ists & USB_ISTS_CON2I || usb_ists & USB_ISTS_CONI)
+		ret += sprintf(str + ret, "Disconnection ");
+	if (usb_ists & USB_ISTS_L2ENTI)
+		ret += sprintf(str + ret, "suspended ");
+
+	if (usb_ists & USB_ISTS_L2EXTI)
+		ret += sprintf(str + ret, "L2 exit ");
+	if (usb_ists & USB_ISTS_U3EXTI)
+		ret += sprintf(str + ret, "U3 exit ");
+	if (usb_ists & USB_ISTS_UWRESI)
+		ret += sprintf(str + ret, "Warm Reset ");
+	if (usb_ists & USB_ISTS_UHRESI)
+		ret += sprintf(str + ret, "Hot Reset ");
+	if (usb_ists & USB_ISTS_U2RESI)
+		ret += sprintf(str + ret, "Reset");
+
+	return str;
+}
+
+static inline  char *cdns3_decode_ep_irq(char *str,
+					 u32 ep_sts,
+					 const char *ep_name)
+{
+	int ret;
+
+	ret = sprintf(str, "IRQ for %s: %08x ", ep_name, ep_sts);
+
+	if (ep_sts & EP_STS_SETUP)
+		ret += sprintf(str + ret, "SETUP ");
+	if (ep_sts & EP_STS_IOC)
+		ret += sprintf(str + ret, "IOC ");
+	if (ep_sts & EP_STS_ISP)
+		ret += sprintf(str + ret, "ISP ");
+	if (ep_sts & EP_STS_DESCMIS)
+		ret += sprintf(str + ret, "DESCMIS ");
+	if (ep_sts & EP_STS_STREAMR)
+		ret += sprintf(str + ret, "STREAMR ");
+	if (ep_sts & EP_STS_MD_EXIT)
+		ret += sprintf(str + ret, "MD_EXIT ");
+	if (ep_sts & EP_STS_TRBERR)
+		ret += sprintf(str + ret, "TRBERR ");
+	if (ep_sts & EP_STS_NRDY)
+		ret += sprintf(str + ret, "NRDY ");
+	if (ep_sts & EP_STS_PRIME)
+		ret += sprintf(str + ret, "PRIME ");
+	if (ep_sts & EP_STS_SIDERR)
+		ret += sprintf(str + ret, "SIDERRT ");
+	if (ep_sts & EP_STS_OUTSMM)
+		ret += sprintf(str + ret, "OUTSMM ");
+	if (ep_sts & EP_STS_ISOERR)
+		ret += sprintf(str + ret, "ISOERR ");
+	if (ep_sts & EP_STS_IOT)
+		ret += sprintf(str + ret, "IOT ");
+
+	return str;
+}
+
+static inline char *cdns3_decode_epx_irq(char *str,
+					 char *ep_name,
+					 u32 ep_sts)
+{
+	return cdns3_decode_ep_irq(str, ep_sts, ep_name);
+}
+
+static inline char *cdns3_decode_ep0_irq(char *str,
+					 int dir,
+					 u32 ep_sts)
+{
+	return cdns3_decode_ep_irq(str, ep_sts,
+				   dir ? "ep0IN" : "ep0OUT");
+}
+
+/**
+ * Debug a transfer ring.
+ *
+ * Prints out all TRBs in the endpoint ring, even those after the Link TRB.
+ *.
+ */
+static inline char *cdns3_dbg_ring(struct cdns3_endpoint *priv_ep,
+				   struct cdns3_trb *ring, char *str)
+{
+	dma_addr_t addr = priv_ep->trb_pool_dma;
+	struct cdns3_trb *trb;
+	int trb_per_sector;
+	int ret = 0;
+	int i;
+
+	trb_per_sector = GET_TRBS_PER_SEGMENT(priv_ep->type);
+
+	trb = &priv_ep->trb_pool[priv_ep->dequeue];
+	ret += sprintf(str + ret, "\n\t\tRing contents for %s:", priv_ep->name);
+
+	ret += sprintf(str + ret,
+		       "\n\t\tRing deq index: %d, trb: %p (virt), 0x%llx (dma)\n",
+		       priv_ep->dequeue, trb,
+		       (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
+
+	trb = &priv_ep->trb_pool[priv_ep->enqueue];
+	ret += sprintf(str + ret,
+		       "\t\tRing enq index: %d, trb: %p (virt), 0x%llx (dma)\n",
+		       priv_ep->enqueue, trb,
+		       (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
+
+	ret += sprintf(str + ret,
+		       "\t\tfree trbs: %d, CCS=%d, PCS=%d\n",
+		       priv_ep->free_trbs, priv_ep->ccs, priv_ep->pcs);
+
+	if (trb_per_sector > TRBS_PER_SEGMENT)
+		trb_per_sector = TRBS_PER_SEGMENT;
+
+	if (trb_per_sector > TRBS_PER_SEGMENT) {
+		sprintf(str + ret, "\t\tTo big transfer ring %d\n",
+			trb_per_sector);
+		return str;
+	}
+
+	for (i = 0; i < trb_per_sector; ++i) {
+		trb = &ring[i];
+		ret += sprintf(str + ret,
+			"\t\t@%pad %08x %08x %08x\n", &addr,
+			le32_to_cpu(trb->buffer),
+			le32_to_cpu(trb->length),
+			le32_to_cpu(trb->control));
+		addr += sizeof(*trb);
+	}
+
+	return str;
+}
+
+void cdns3_dbg(struct cdns3_device *priv_dev, const char *fmt, ...);
+
+#ifdef CONFIG_DEBUG_FS
+void cdns3_debugfs_init(struct cdns3 *cdns);
+void cdns3_debugfs_exit(struct cdns3 *cdns);
+#else
+void cdns3_debugfs_init(struct cdns3 *cdns);
+{  }
+void cdns3_debugfs_exit(struct cdns3 *cdns);
+{  }
+#endif
+
+#endif /*__LINUX_CDNS3_DEBUG*/

diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
new file mode 100644
index 000000000000..d8fcd90d05b3
--- /dev/null
+++ b/drivers/usb/cdns3/debugfs.c

@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Controller DebugFS filer.
+ *
+ * Copyright (C) 2018 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+
+#include <linux/types.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+
+#include "core.h"
+#include "gadget.h"
+#include "drd.h"
+
+static int cdns3_mode_show(struct seq_file *s, void *unused)
+{
+	struct cdns3 *cdns = s->private;
+
+	switch (cdns->current_dr_mode) {
+	case USB_DR_MODE_HOST:
+		seq_puts(s, "host\n");
+		break;
+	case USB_DR_MODE_PERIPHERAL:
+		seq_puts(s, "device\n");
+		break;
+	case USB_DR_MODE_OTG:
+		seq_puts(s, "otg\n");
+		break;
+	default:
+		seq_puts(s, "UNKNOWN mode\n");
+	}
+
+	return 0;
+}
+
+static int cdns3_mode_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, cdns3_mode_show, inode->i_private);
+}
+
+static ssize_t cdns3_mode_write(struct file *file,
+				const char __user *ubuf,
+				size_t count, loff_t *ppos)
+{
+	struct seq_file	 *s = file->private_data;
+	struct cdns3 *cdns = s->private;
+	u32 mode = USB_DR_MODE_UNKNOWN;
+	char buf[32];
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	if (!strncmp(buf, "host", 4)) {
+		if (cdns->dr_mode == USB_DR_MODE_HOST ||
+		    cdns->dr_mode == USB_DR_MODE_OTG) {
+			mode = USB_DR_MODE_HOST;
+		}
+	}
+
+	if (!strncmp(buf, "device", 6))
+		if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL ||
+		    cdns->dr_mode == USB_DR_MODE_OTG)
+			mode = USB_DR_MODE_PERIPHERAL;
+
+	if (!strncmp(buf, "otg", 3) && cdns->dr_mode == USB_DR_MODE_OTG)
+		mode = USB_DR_MODE_OTG;
+
+	if (mode == USB_DR_MODE_UNKNOWN) {
+		dev_err(cdns->dev, "Failed: incorrect mode setting\n");
+		return -EFAULT;
+	}
+
+	if (cdns->current_dr_mode != mode) {
+		cdns->desired_dr_mode = mode;
+		cdns->debug_disable = 0;

+	}
+
+	return count;
+}
+
+static int cdns3_disable_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, cdns3_disable_show, inode->i_private);
+}
+
+static const struct file_operations cdns3_disable_fops = {
+	.open			= cdns3_disable_open,
+	.write			= cdns3_disable_write,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
+};
+
+void cdns3_debugfs_init(struct cdns3 *cdns)
+{
+	struct dentry *root;
+
+	root = debugfs_create_dir(dev_name(cdns->dev), NULL);
+	cdns->root = root;
+	if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET) &&
+	    IS_ENABLED(CONFIG_USB_CDNS3_HOST))
+		debugfs_create_file("mode", 0644, root, cdns,
+				    &cdns3_mode_fops);
+
+	debugfs_create_file("disable", 0644, root, cdns,
+			    &cdns3_disable_fops);
+}
+
+void cdns3_debugfs_exit(struct cdns3 *cdns)
+{
+	debugfs_remove_recursive(cdns->root);
+}

diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
new file mode 100644
index 000000000000..3e56338cd7b9
--- /dev/null
+++ b/drivers/usb/cdns3/drd.c

@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2018 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/usb/otg.h>
+
+#include "gadget.h"
+#include "drd.h"
+#include "core.h"
+
+static int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on);
+static int cdns3_drd_switch_host(struct cdns3 *cdns, int on);
+
+/**
+ * cdns3_set_mode - change mode of OTG Core
+ * @cdns: pointer to context structure
+ * @mode: selected mode from cdns_role
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+int cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
+{
+	int ret = 0;
+	u32 reg;
+
+	cdns->current_dr_mode = mode;
+
+	switch (mode) {
+	case USB_DR_MODE_PERIPHERAL:
+		dev_info(cdns->dev, "Set controller to Gadget mode\n");

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
new file mode 100644
index 000000000000..7f7f24ee3c4b
--- /dev/null
+++ b/drivers/usb/cdns3/gadget.c

@@ -0,0 +1,2003 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver - gadget side.
+ *
+ * Copyright (C) 2018 Cadence Design Systems.
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Authors: Pawel Jez <pjez@cadence.com>,
+ *          Pawel Laszczak <pawell@cadence.com>
+ *	    Peter Chen <peter.chen@nxp.com>
+ */
+