usb:cdns3 Add Cadence USB3 DRD Driver

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

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

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

The host side of USBSS-DRD controller is compliant with XHCI
specification, so it works with standard XHCI Linux driver.
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/Kconfig

@@ -113,6 +113,8 @@ source "drivers/usb/usbip/Kconfig"
 
 endif
 
+source "drivers/usb/cdns3/Kconfig"
+
 source "drivers/usb/mtu3/Kconfig"
 
 source "drivers/usb/musb/Kconfig"

drivers/usb/Makefile

@@ -13,6 +13,8 @@ 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/
 

drivers/usb/cdns3/Kconfig

+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

drivers/usb/cdns3/Makefile

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

drivers/usb/cdns3/cdns3-pci-wrap.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS PCI Glue driver
+ *
+ * Copyright (C) 2018-2019 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+
+#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[6];
+};
+
+#define RES_IRQ_HOST_ID		0
+#define RES_IRQ_PERIPHERAL_ID	1
+#define RES_IRQ_OTG_ID		2
+#define RES_HOST_ID		3
+#define RES_DEV_ID		4
+#define RES_DRD_ID		5
+
+#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
+
+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) {
+		pci_disable_device(pdev);
+		return -ENOMEM;
+	}
+
+	/* function 0: host(BAR_0) + device(BAR_1) + otg(BAR_2)). */
+	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 for XHCI */
+	wrap->dev_res[RES_IRQ_HOST_ID].start = pdev->irq;
+	wrap->dev_res[RES_IRQ_HOST_ID].name = "host";
+	wrap->dev_res[RES_IRQ_HOST_ID].flags = IORESOURCE_IRQ;
+
+	/* Interrupt device. It's the same as for HOST. */
+	wrap->dev_res[RES_IRQ_PERIPHERAL_ID].start = pdev->irq;
+	wrap->dev_res[RES_IRQ_PERIPHERAL_ID].name = "peripheral";
+	wrap->dev_res[RES_IRQ_PERIPHERAL_ID].flags = IORESOURCE_IRQ;
+
+	/* Interrupt for OTG/DRD. */
+	wrap->dev_res[RES_IRQ_OTG_ID].start = pdev->irq;
+	wrap->dev_res[RES_IRQ_OTG_ID].name = "otg";
+	wrap->dev_res[RES_IRQ_OTG_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)) {
+		pci_disable_device(pdev);
+		return PTR_ERR(wrap->plat_dev);
+	}
+
+	pci_set_drvdata(pdev, wrap);
+
+	return err;
+}
+
+static 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 <pawell@cadence.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Cadence USBSS PCI wrapperr");

drivers/usb/cdns3/core.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Header File.
+ *
+ * Copyright (C) 2017-2018 NXP
+ * Copyright (C) 2018-2019 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_IDLE = 0,
+	CDNS3_ROLE_HOST,
+	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_res: the resource for otg
+ * @otg_v0_regs: pointer to base of v0 otg registers
+ * @otg_v1_regs: pointer to base of v1 otg registers
+ * @otg_regs: pointer to base of otg registers
+ * @otg_irq: irq number for otg controller
+ * @dev_irq: irq number for device 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
+ * @usb2_phy: pointer to USB2 PHY
+ * @usb3_phy: pointer to USB3 PHY
+ * @role_switch_wq: work queue item for role switch
+ * @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         | USB_DR_MODE_OTG or USB_DR_MODE_HOST or
+ *                                   | USB_DR_MODE_PERIPHERAL
+ *           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				otg_irq;
+	int				dev_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			*usb2_phy;
+	struct phy			*usb3_phy;
+	struct work_struct		role_switch_wq;
+	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);
+int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec);
+
+#endif /* __LINUX_CDNS3_CORE_H */

drivers/usb/cdns3/debug.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Driver.
+ * Debug header file.
+ *
+ * Copyright (C) 2018-2019 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_DIS2I || usb_ists & USB_ISTS_DISI)
+		ret += sprintf(str + ret, "Disconnection ");
+	if (usb_ists & USB_ISTS_L2ENTI)
+		ret += sprintf(str + ret, "suspended ");
+	if (usb_ists & USB_ISTS_L1ENTI)
+		ret += sprintf(str + ret, "L1 enter ");
+	if (usb_ists & USB_ISTS_L1EXTI)
+		ret += sprintf(str + ret, "L1 exit ");
+	if (usb_ists & USB_ISTS_L2ENTI)
+		ret += sprintf(str + ret, "L2 enter ");
+	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*/

drivers/usb/cdns3/debugfs.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Controller DebugFS filer.
+ *
+ * Copyright (C) 2018-2019 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 const char *const cdns3_mode[] = {
+	[USB_DR_MODE_UNKNOWN]		= "unknown",
+	[USB_DR_MODE_OTG]		= "otg",
+	[USB_DR_MODE_HOST]		= "host",
+	[USB_DR_MODE_PERIPHERAL]	= "device",
+};
+
+static int cdns3_mode_show(struct seq_file *s, void *unused)
+{
+	struct cdns3 *cdns = s->private;
+
+	seq_puts(s, cdns3_mode[cdns->current_dr_mode]);
+
+	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;
+	char buf[32];
+	int ret;
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	if (cdns->debug_disable) {
+		dev_err(cdns->dev,
+			"Mode can't be changed when disable is set\n");
+		return -EPERM;
+	}
+
+	ret = match_string(cdns3_mode, ARRAY_SIZE(cdns3_mode), buf);
+	if (ret < 0 || ret == USB_DR_MODE_UNKNOWN) {
+		dev_err(cdns->dev, "Failed: incorrect mode setting\n");
+		return -EINVAL;
+	}
+
+	if (cdns->current_dr_mode != ret) {
+		cdns->desired_dr_mode = ret;
+		cdns3_role_stop(cdns);
+		ret = cdns3_drd_update_mode(cdns);
+		if (ret)
+			return ret;
+
+		queue_work(system_freezable_wq, &cdns->role_switch_wq);
+	}
+
+	return count;
+}
+
+static const struct file_operations cdns3_mode_fops = {
+	.open			= cdns3_mode_open,
+	.write			= cdns3_mode_write,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
+};
+
+static int cdns3_disable_show(struct seq_file *s, void *unused)
+{
+	struct cdns3 *cdns = s->private;
+
+	if (!cdns->debug_disable)
+		seq_puts(s, "0\n");
+	else
+		seq_puts(s, "1\n");
+
+	return 0;
+}
+
+static ssize_t cdns3_disable_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;
+	bool disable;
+	char buf[16];
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	if (kstrtobool(buf, &disable)) {
+		dev_err(cdns->dev, "wrong setting\n");
+		return -EINVAL;
+	}
+
+	if (disable != cdns->debug_disable) {
+		cdns->debug_disable = disable;
+		queue_work(system_freezable_wq, &cdns->role_switch_wq);
+	}
+
+	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);
+}

drivers/usb/cdns3/drd.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver.
+ *
+ * Copyright (C) 2018-2019 Cadence.
+ * Copyright (C) 2019 Texas Instruments
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ *         Roger Quadros <rogerq@ti.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"
+
+/**
+ * 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:
+		break;
+	case USB_DR_MODE_HOST:
+		break;
+	case USB_DR_MODE_OTG:
+		dev_dbg(cdns->dev, "Set controller to OTG mode\n");
+		if (cdns->version == CDNS3_CONTROLLER_V1) {
+			reg = readl(&cdns->otg_v1_regs->override);
+			reg |= OVERRIDE_IDPULLUP;
+			writel(reg, &cdns->otg_v1_regs->override);
+		} else {
+			reg = readl(&cdns->otg_v0_regs->ctrl1);
+			reg |= OVERRIDE_IDPULLUP_V0;
+			writel(reg, &cdns->otg_v0_regs->ctrl1);
+		}
+
+		/*
+		 * Hardware specification says: "ID_VALUE must be valid within
+		 * 50ms after idpullup is set to '1" so driver must wait
+		 * 50ms before reading this pin.
+		 */
+		usleep_range(50000, 60000);
+		break;
+	default:
+		cdns->current_dr_mode = USB_DR_MODE_UNKNOWN;
+		dev_err(cdns->dev, "Unsupported mode of operation %d\n", mode);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+int cdns3_get_id(struct cdns3 *cdns)
+{
+	int id;
+
+	id = readl(&cdns->otg_regs->sts) & OTGSTS_ID_VALUE;
+	dev_dbg(cdns->dev, "OTG ID: %d", id);
+
+	return id;
+}
+
+int cdns3_get_vbus(struct cdns3 *cdns)
+{
+	int vbus;
+
+	vbus = !!(readl(&cdns->otg_regs->sts) & OTGSTS_VBUS_VALID);
+	dev_dbg(cdns->dev, "OTG VBUS: %d", vbus);
+	return vbus;
+}
+
+int cdns3_is_host(struct cdns3 *cdns)
+{
+	if (cdns->current_dr_mode == USB_DR_MODE_HOST)
+		return 1;
+	else if (!cdns3_get_id(cdns))
+		return 1;
+
+	return 0;
+}
+
+int cdns3_is_device(struct cdns3 *cdns)
+{
+	if (cdns->current_dr_mode == USB_DR_MODE_PERIPHERAL)
+		return 1;
+	else if (cdns->current_dr_mode == USB_DR_MODE_OTG)
+		if (cdns3_get_id(cdns))
+			return 1;
+
+	return 0;
+}
+
+/**
+ * cdns3_otg_disable_irq - Disable all OTG interrupts
+ * @cdns: Pointer to controller context structure
+ */
+static void cdns3_otg_disable_irq(struct cdns3 *cdns)
+{
+	writel(0, &cdns->otg_regs->ien);
+}
+
+/**
+ * cdns3_otg_enable_irq - enable id and sess_valid interrupts
+ * @cdns: Pointer to controller context structure
+ */
+static void cdns3_otg_enable_irq(struct cdns3 *cdns)
+{
+	writel(OTGIEN_ID_CHANGE_INT | OTGIEN_VBUSVALID_RISE_INT |
+	       OTGIEN_VBUSVALID_FALL_INT, &cdns->otg_regs->ien);
+}
+
+/**
+ * cdns3_drd_switch_host - start/stop host
+ * @cdns: Pointer to controller context structure
+ * @on: 1 for start, 0 for stop
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+int cdns3_drd_switch_host(struct cdns3 *cdns, int on)
+{
+	int ret;
+	u32 reg = OTGCMD_OTG_DIS;
+
+	/* switch OTG core */
+	if (on) {
+		writel(OTGCMD_HOST_BUS_REQ | reg, &cdns->otg_regs->cmd);
+
+		dev_dbg(cdns->dev, "Waiting till Host mode is turned on\n");
+		ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_XHCI_READY,
+				      OTGSTS_XHCI_READY, 100000);
+
+		if (ret) {
+			dev_err(cdns->dev, "timeout waiting for xhci_ready\n");
+			return ret;
+		}
+	} else {
+		writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP |
+		       OTGCMD_DEV_POWER_OFF | OTGCMD_HOST_POWER_OFF,
+		       &cdns->otg_regs->cmd);
+		/* Waiting till H_IDLE state.*/
+		cdns3_handshake(&cdns->otg_regs->state,
+				OTGSTATE_HOST_STATE_MASK,
+				0, 2000000);
+	}
+
+	return 0;
+}
+
+/**
+ * cdns3_drd_switch_gadget - start/stop gadget
+ * @cdns: Pointer to controller context structure
+ * @on: 1 for start, 0 for stop
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on)
+{
+	int ret;
+	u32 reg = OTGCMD_OTG_DIS;
+
+	/* switch OTG core */
+	if (on) {
+		writel(OTGCMD_DEV_BUS_REQ | reg, &cdns->otg_regs->cmd);
+
+		dev_dbg(cdns->dev, "Waiting till Device mode is turned on\n");
+
+		ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_DEV_READY,
+				      OTGSTS_DEV_READY, 100000);
+
+		if (ret) {
+			dev_err(cdns->dev, "timeout waiting for dev_ready\n");
+			return ret;
+		}
+	} else {
+		/*
+		 * driver should wait at least 10us after disabling Device
+		 * before turning-off Device (DEV_BUS_DROP)
+		 */
+		usleep_range(20, 30);
+		writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP |
+		       OTGCMD_DEV_POWER_OFF | OTGCMD_HOST_POWER_OFF,
+		       &cdns->otg_regs->cmd);
+		/* Waiting till DEV_IDLE state.*/
+		cdns3_handshake(&cdns->otg_regs->state, OTGSTATE_DEV_STATE_MASK,
+				0, 2000000);
+	}
+
+	return 0;
+}
+
+/**
+ * cdns3_init_otg_mode - initialize drd controller
+ * @cdns: Pointer to controller context structure
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+static int cdns3_init_otg_mode(struct cdns3 *cdns)
+{
+	int ret = 0;
+
+	cdns3_otg_disable_irq(cdns);
+	/* clear all interrupts */
+	writel(~0, &cdns->otg_regs->ivect);
+
+	ret = cdns3_set_mode(cdns, USB_DR_MODE_OTG);
+	if (ret)
+		return ret;
+
+	cdns3_otg_enable_irq(cdns);
+	return ret;
+}
+
+/**
+ * cdns3_drd_update_mode - initialize mode of operation
+ * @cdns: Pointer to controller context structure
+ *
+ * Returns 0 on success otherwise negative errno
+ */
+int cdns3_drd_update_mode(struct cdns3 *cdns)
+{
+	int ret = 0;
+
+	if (cdns->desired_dr_mode == cdns->current_dr_mode)
+		return ret;
+
+	switch (cdns->desired_dr_mode) {
+	case USB_DR_MODE_PERIPHERAL:
+		ret = cdns3_set_mode(cdns, USB_DR_MODE_PERIPHERAL);
+		break;
+	case USB_DR_MODE_HOST:
+		ret = cdns3_set_mode(cdns, USB_DR_MODE_HOST);
+		break;
+	case USB_DR_MODE_OTG:
+		ret = cdns3_init_otg_mode(cdns);
+		break;
+	default:
+		dev_err(cdns->dev, "Unsupported mode of operation %d\n",
+			cdns->dr_mode);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * cdns3_drd_irq - interrupt handler for OTG events
+ *
+ * @irq: irq number for cdns3 core device
+ * @data: structure of cdns3
+ *
+ * Returns IRQ_HANDLED or IRQ_NONE
+ */
+static irqreturn_t cdns3_drd_irq(int irq, void *data)
+{
+	irqreturn_t ret = IRQ_NONE;
+	struct cdns3 *cdns = data;
+	u32 reg;
+
+	if (cdns->dr_mode != USB_DR_MODE_OTG)
+		return ret;
+
+	reg = readl(&cdns->otg_regs->ivect);
+
+	if (!reg)
+		return ret;
+
+	if (reg & OTGIEN_ID_CHANGE_INT) {
+		dev_dbg(cdns->dev, "OTG IRQ: new ID: %d\n",
+			cdns3_get_id(cdns));
+
+		ret = IRQ_HANDLED;
+	}
+
+	if (reg & (OTGIEN_VBUSVALID_RISE_INT | OTGIEN_VBUSVALID_FALL_INT)) {
+		dev_dbg(cdns->dev, "OTG IRQ: new VBUS: %d\n",
+			cdns3_get_vbus(cdns));
+
+		ret = IRQ_HANDLED;
+	}
+
+	if (ret == IRQ_HANDLED)
+		queue_work(system_freezable_wq, &cdns->role_switch_wq);
+
+	writel(~0, &cdns->otg_regs->ivect);
+	return ret;
+}
+
+int cdns3_drd_init(struct cdns3 *cdns)
+{
+	void __iomem *regs;
+	int ret = 0;
+	u32 state;
+
+	regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	/* Detection of DRD version. Controller has been released
+	 * in two versions. Both are similar, but they have same changes
+	 * in register maps.
+	 * The first register in old version is command register and it's read
+	 * only, so driver should read 0 from it. On the other hand, in v1
+	 * the first register contains device ID number which is not set to 0.
+	 * Driver uses this fact to detect the proper version of
+	 * controller.
+	 */
+	cdns->otg_v0_regs = regs;
+	if (!readl(&cdns->otg_v0_regs->cmd)) {
+		cdns->version  = CDNS3_CONTROLLER_V0;
+		cdns->otg_v1_regs = NULL;
+		cdns->otg_regs = regs;
+		writel(1, &cdns->otg_v0_regs->simulate);
+		dev_info(cdns->dev, "DRD version v0 (%08x)\n",
+			 readl(&cdns->otg_v0_regs->version));
+	} else {
+		cdns->otg_v0_regs = NULL;
+		cdns->otg_v1_regs = regs;
+		cdns->otg_regs = (void *)&cdns->otg_v1_regs->cmd;
+		cdns->version  = CDNS3_CONTROLLER_V1;
+		writel(1, &cdns->otg_v1_regs->simulate);
+		dev_info(cdns->dev, "DRD version v1 (ID: %08x, rev: %08x)\n",
+			 readl(&cdns->otg_v1_regs->did),
+			 readl(&cdns->otg_v1_regs->rid));
+	}
+
+	state = OTGSTS_STRAP(readl(&cdns->otg_regs->sts));
+
+	/* Update dr_mode according to STRAP configuration. */
+	cdns->dr_mode = USB_DR_MODE_OTG;
+	if (state == OTGSTS_STRAP_HOST) {
+		dev_dbg(cdns->dev, "Controller strapped to HOST\n");
+		cdns->dr_mode = USB_DR_MODE_HOST;
+	} else if (state == OTGSTS_STRAP_GADGET) {
+		dev_dbg(cdns->dev, "Controller strapped to PERIPHERAL\n");
+		cdns->dr_mode = USB_DR_MODE_PERIPHERAL;
+	}
+
+	cdns->desired_dr_mode = cdns->dr_mode;
+	cdns->current_dr_mode = USB_DR_MODE_UNKNOWN;
+
+	ret = devm_request_threaded_irq(cdns->dev, cdns->otg_irq,
+					cdns3_drd_irq,
+					NULL, IRQF_SHARED,
+					dev_name(cdns->dev), cdns);
+
+	if (ret) {
+		dev_err(cdns->dev, "couldn't get otg_irq\n");
+		return ret;
+	}
+
+	state = readl(&cdns->otg_regs->sts);
+	if (OTGSTS_OTG_NRDY(state) != 0) {
+		dev_err(cdns->dev, "Cadence USB3 OTG device not ready\n");
+		return -ENODEV;
+	}
+
+	return ret;
+}
+
+int cdns3_drd_exit(struct cdns3 *cdns)
+{
+	return 0;
+}

drivers/usb/cdns3/drd.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USB3 DRD header file.
+ *
+ * Copyright (C) 2018-2019 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+#ifndef __LINUX_CDNS3_DRD
+#define __LINUX_CDNS3_DRD
+
+#include <linux/usb/otg.h>
+#include <linux/phy/phy.h>
+#include "core.h"
+
+/*  DRD register interface for version v1. */
+struct cdns3_otg_regs {
+	__le32 did;
+	__le32 rid;
+	__le32 capabilities;
+	__le32 reserved1;
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 reserved2;
+	__le32 ien;
+	__le32 ivect;
+	__le32 refclk;
+	__le32 tmr;
+	__le32 reserved3[4];
+	__le32 simulate;
+	__le32 override;
+	__le32 susp_ctrl;
+	__le32 reserved4;
+	__le32 anasts;
+	__le32 adp_ramp_time;
+	__le32 ctrl1;
+	__le32 ctrl2;
+};
+
+/*  DRD register interface for version v0. */
+struct cdns3_otg_legacy_regs {
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 refclk;
+	__le32 ien;
+	__le32 ivect;
+	__le32 reserved1[3];
+	__le32 tmr;
+	__le32 reserved2[2];
+	__le32 version;
+	__le32 capabilities;
+	__le32 reserved3[2];
+	__le32 simulate;
+	__le32 reserved4[5];
+	__le32 ctrl1;
+};
+
+/*
+ * Common registers interface for both version of DRD.
+ */
+struct cdns3_otg_common_regs {
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 different1;
+	__le32 ien;
+	__le32 ivect;
+};
+
+/* CDNS_RID - bitmasks */
+#define CDNS_RID(p)			((p) & GENMASK(15, 0))
+
+/* CDNS_VID - bitmasks */
+#define CDNS_DID(p)			((p) & GENMASK(31, 0))
+
+/* OTGCMD - bitmasks */
+/* "Request the bus for Device mode. */
+#define OTGCMD_DEV_BUS_REQ		BIT(0)
+/* Request the bus for Host mode */
+#define OTGCMD_HOST_BUS_REQ		BIT(1)
+/* Enable OTG mode. */
+#define OTGCMD_OTG_EN			BIT(2)
+/* Disable OTG mode */
+#define OTGCMD_OTG_DIS			BIT(3)
+/*"Configure OTG as A-Device. */
+#define OTGCMD_A_DEV_EN			BIT(4)
+/*"Configure OTG as A-Device. */
+#define OTGCMD_A_DEV_DIS		BIT(5)
+/* Drop the bus for Device mod	e. */
+#define OTGCMD_DEV_BUS_DROP		BIT(8)
+/* Drop the bus for Host mode*/
+#define OTGCMD_HOST_BUS_DROP		BIT(9)
+/* Power Down USBSS-DEV. */
+#define OTGCMD_DEV_POWER_OFF		BIT(11)
+/* Power Down CDNSXHCI. */
+#define OTGCMD_HOST_POWER_OFF		BIT(12)
+
+/* OTGIEN - bitmasks */
+/* ID change interrupt enable */
+#define OTGIEN_ID_CHANGE_INT		BIT(0)
+/* Vbusvalid fall detected interrupt enable.*/
+#define OTGIEN_VBUSVALID_RISE_INT	BIT(4)
+/* Vbusvalid fall detected interrupt enable */
+#define OTGIEN_VBUSVALID_FALL_INT	BIT(5)
+
+/* OTGSTS - bitmasks */
+/*
+ * Current value of the ID pin. It is only valid when idpullup in
+ *  OTGCTRL1_TYPE register is set to '1'.
+ */
+#define OTGSTS_ID_VALUE			BIT(0)
+/* Current value of the vbus_valid */
+#define OTGSTS_VBUS_VALID		BIT(1)
+/* Current value of the b_sess_vld */
+#define OTGSTS_SESSION_VALID		BIT(2)
+/*Device mode is active*/
+#define OTGSTS_DEV_ACTIVE		BIT(3)
+/* Host mode is active. */
+#define OTGSTS_HOST_ACTIVE		BIT(4)
+/* OTG Controller not ready. */
+#define OTGSTS_OTG_NRDY_MASK		BIT(11)
+#define OTGSTS_OTG_NRDY(p)		((p) & OTGSTS_OTG_NRDY_MASK)
+/*
+ * Value of the strap pins.
+ * 000 - no default configuration
+ * 010 - Controller initiall configured as Host
+ * 100 - Controller initially configured as Device
+ */
+#define OTGSTS_STRAP(p)			(((p) & GENMASK(14, 12)) >> 12)
+#define OTGSTS_STRAP_NO_DEFAULT_CFG	0x00
+#define OTGSTS_STRAP_HOST_OTG		0x01
+#define OTGSTS_STRAP_HOST		0x02
+#define OTGSTS_STRAP_GADGET		0x04
+/* Host mode is turned on. */
+#define OTGSTS_XHCI_READY		BIT(26)
+/* "Device mode is turned on .*/
+#define OTGSTS_DEV_READY		BIT(27)
+
+/* OTGSTATE- bitmasks */
+#define OTGSTATE_DEV_STATE_MASK		GENMASK(2, 0)
+#define OTGSTATE_HOST_STATE_MASK	GENMASK(5, 3)
+#define OTGSTATE_HOST_STATE_IDLE	0x0
+#define OTGSTATE_HOST_STATE_VBUS_FALL	0x7
+#define OTGSTATE_HOST_STATE(p)		(((p) & OTGSTATE_HOST_STATE_MASK) >> 3)
+
+/* OTGREFCLK - bitmasks */
+#define OTGREFCLK_STB_CLK_SWITCH_EN	BIT(31)
+
+/* OVERRIDE - bitmasks */
+#define OVERRIDE_IDPULLUP		BIT(0)
+/* Only for CDNS3_CONTROLLER_V0 version */
+#define OVERRIDE_IDPULLUP_V0		BIT(24)
+
+int cdns3_is_host(struct cdns3 *cdns);
+int cdns3_is_device(struct cdns3 *cdns);
+int cdns3_get_id(struct cdns3 *cdns);
+int cdns3_get_vbus(struct cdns3 *cdns);
+int cdns3_drd_init(struct cdns3 *cdns);
+int cdns3_drd_exit(struct cdns3 *cdns);
+int cdns3_drd_update_mode(struct cdns3 *cdns);
+int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on);
+int cdns3_drd_switch_host(struct cdns3 *cdns, int on);
+
+#endif /* __LINUX_CDNS3_DRD */

drivers/usb/cdns3/gadget-export.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Driver - Gadget Export APIs.
+ *
+ * Copyright (C) 2017 NXP
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Authors: Peter Chen <peter.chen@nxp.com>
+ */
+#ifndef __LINUX_CDNS3_GADGET_EXPORT
+#define __LINUX_CDNS3_GADGET_EXPORT
+
+#ifdef CONFIG_USB_CDNS3_GADGET
+
+int cdns3_gadget_init(struct cdns3 *cdns);
+void cdns3_gadget_exit(struct cdns3 *cdns);
+#else
+
+static inline int cdns3_gadget_init(struct cdns3 *cdns)
+{
+	return -ENXIO;
+}
+
+static inline void cdns3_gadget_exit(struct cdns3 *cdns) { }
+
+#endif
+
+#endif /* __LINUX_CDNS3_GADGET_EXPORT */

drivers/usb/cdns3/host-export.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USBSS DRD Driver - Host Export APIs
+ *
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Authors: Peter Chen <peter.chen@nxp.com>
+ */
+#ifndef __LINUX_CDNS3_HOST_EXPORT
+#define __LINUX_CDNS3_HOST_EXPORT
+
+#ifdef CONFIG_USB_CDNS3_HOST
+
+int cdns3_host_init(struct cdns3 *cdns);
+void cdns3_host_exit(struct cdns3 *cdns);
+
+#else
+
+static inline int cdns3_host_init(struct cdns3 *cdns)
+{
+	return -ENXIO;
+}
+
+static inline void cdns3_host_exit(struct cdns3 *cdns) { }
+
+#endif /* CONFIG_USB_CDNS3_HOST */
+
+#endif /* __LINUX_CDNS3_HOST_EXPORT */

drivers/usb/cdns3/host.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence USBSS DRD Driver - host side
+ *
+ * Copyright (C) 2018 Cadence Design Systems.
+ * Copyright (C) 2017-2018 NXP
+ *
+ * Authors: Peter Chen <peter.chen@nxp.com>
+ *          Pawel Laszczak <pawell@cadence.com>
+ */
+
+#include <linux/platform_device.h>
+#include "core.h"
+#include "drd.h"
+
+static int __cdns3_host_init(struct cdns3 *cdns)
+{
+	struct platform_device *xhci;
+	int ret;
+
+	cdns3_drd_switch_host(cdns, 1);
+
+	xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
+	if (!xhci) {
+		dev_err(cdns->dev, "couldn't allocate xHCI device\n");
+		return -ENOMEM;
+	}
+
+	xhci->dev.parent = cdns->dev;
+	cdns->host_dev = xhci;
+
+	ret = platform_device_add_resources(xhci, cdns->xhci_res,
+					    CDNS3_XHCI_RESOURCES_NUM);
+	if (ret) {
+		dev_err(cdns->dev, "couldn't add resources to xHCI device\n");
+		goto err1;
+	}
+
+	ret = platform_device_add(xhci);
+	if (ret) {
+		dev_err(cdns->dev, "failed to register xHCI device\n");
+		goto err1;
+	}
+
+	return 0;
+err1:
+	platform_device_put(xhci);
+	return ret;
+}
+
+static void cdns3_host_exit(struct cdns3 *cdns)
+{
+	platform_device_unregister(cdns->host_dev);
+	cdns->host_dev = NULL;
+	cdns3_drd_switch_host(cdns, 0);
+}
+
+int cdns3_host_init(struct cdns3 *cdns)
+{
+	struct cdns3_role_driver *rdrv;
+
+	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
+	if (!rdrv)
+		return -ENOMEM;
+
+	rdrv->start	= __cdns3_host_init;
+	rdrv->stop	= cdns3_host_exit;
+	rdrv->state	= CDNS3_ROLE_STATE_INACTIVE;
+	rdrv->suspend	= NULL;
+	rdrv->resume	= NULL;
+	rdrv->name	= "host";
+
+	cdns->roles[CDNS3_ROLE_HOST] = rdrv;
+
+	return 0;
+}

drivers/usb/cdns3/trace.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USBSS device controller driver Trace Support
+ *
+ * Copyright (C) 2018 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+void cdns3_dbg(struct cdns3_device *priv_dev, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+	trace_cdns3_log(priv_dev, &vaf);
+	va_end(args);
+}