RE: [PATCH v4 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
From: Pawel Laszczak
Date: Mon Mar 04 2019 - 07:48:32 EST
>From: Pawel Laszczak
>Sent: Monday, March 4, 2019 12:02 PM
>To: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
>Cc: devicetree@xxxxxxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; felipe.balbi@xxxxxxxxxxxxxxx; mark.rutland@xxxxxxx; linux-
>usb@xxxxxxxxxxxxxxx; hdegoede@xxxxxxxxxx; heikki.krogerus@xxxxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx; robh+dt@xxxxxxxxxx;
>rogerq@xxxxxx; linux-kernel@xxxxxxxxxxxxxxx; jbergsagel@xxxxxx; nsekhar@xxxxxx; nm@xxxxxx; Suresh Punnoose
><sureshp@xxxxxxxxxxx>; peter.chen@xxxxxxx; Rahul Kumar <kurahul@xxxxxxxxxxx>
>Subject: RE: [PATCH v4 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
>
>Hi,
>>
>>hi,
>>On Thu, 2019-02-14 at 19:45 +0000, Pawel Laszczak wrote:
>>> 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@xxxxxxxxxxx>
>>> ---
>>> 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
>>when build as module:
>>CONFIG_USB_CDNS3=m
>>CONFIG_USB_CDNS3_GADGET=m
>>CONFIG_USB_CDNS3_HOST=m
>
>How you set such configuration ? From make menuconfig it's impossible.
>
>>there is an error:
>>ERROR: "cdns3_handshake" [drivers/usb/cdns3/cdns3.ko] undefined!
>>
>>when only set:
>>CONFIG_USB_CDNS3=y
>>also encounter errors:
>>drivers/usb/cdns3/drd.o: In function `cdns3_drd_switch_gadget':
>>/drivers/usb/cdns3/drd.c:173: undefined reference to `cdns3_handshake'
>>drivers/usb/cdns3/drd.o: In function `cdns3_drd_switch_host':
>>drivers/usb/cdns3/drd.c:139: undefined reference to `cdns3_handshake'
>
>I will check this.
>Thanks.
To fix this issue I will move cdns3_handshake function to core.c file.
I know that it's not a perfect place for this function, but I don't
want to create next .c file with this function.
>
>>
>>
>>
>>> 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 <pawell@xxxxxxxxxxx>
>>> + */
>>> +
>>> +#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;
>>not used in fact?
>
>Yes, I forgot to remove it.
>>
>>> +
>>> +#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));
>>Mabye not necessary, devm_kzalloc() already set them as 0;
>
>Yes, it's not necessary.
>>
>>> + 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 <pawell@xxxxxxxxxxx>");
>>> +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@xxxxxxx>
>>> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
>>> + */
>>> +
>>> +#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
>>> + * chooses mode according with Kernel configuration. This setting
>>> + * can be restricted later depending on strap pin configuration.
>>> + */
>>> + if (dr_mode == USB_DR_MODE_UNKNOWN) {
>>> + if (IS_ENABLED(CONFIG_USB_CDNS3_HOST) &&
>>> + IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
>>> + dr_mode = USB_DR_MODE_OTG;
>>> + else if (IS_ENABLED(CONFIG_USB_CDNS3_HOST))
>>> + dr_mode = USB_DR_MODE_HOST;
>>> + else if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
>>> + dr_mode = USB_DR_MODE_PERIPHERAL;
>>> + }
>>> +
>>> + best_dr_mode = USB_DR_MODE_OTG;
>>> +
>>> + if (dr_mode == USB_DR_MODE_OTG) {
>>> + best_dr_mode = cdns->dr_mode;
>>> + } else if (cdns->dr_mode == USB_DR_MODE_OTG) {
>>> + best_dr_mode = dr_mode;
>>> + } else if (cdns->dr_mode != dr_mode) {
>>> + dev_err(dev, "Incorrect DRD configuration\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + dr_mode = best_dr_mode;
>>> +
>>> + if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
>>> + ret = cdns3_host_init(cdns);
>>> + if (ret) {
>>> + dev_err(dev, "Host initialization failed with %d\n",
>>> + ret);
>>> + goto err;
>>> + }
>>> + }
>>> +
>>> + if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
>>> + ret = cdns3_gadget_init(cdns);
>>> + if (ret) {
>>> + dev_err(dev, "Device initialization failed with %d\n",
>>> + ret);
>>> + goto err;
>>> + }
>>> + }
>>> +
>>> + cdns->desired_dr_mode = dr_mode;
>>> + cdns->dr_mode = dr_mode;
>>> + /*
>>> + * dr_mode could be change so DRD must update controller
>>> + * configuration
>>> + */
>>> + ret = cdns3_drd_update_mode(cdns);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + cdns->role = cdns3_get_initial_role(cdns);
>>> +
>>> + ret = cdns3_role_start(cdns, cdns->role);
>>> + if (ret) {
>>> + dev_err(dev, "can't start %s role\n",
>>> + cdns3_get_current_role_driver(cdns)->name);
>>> + goto err;
>>> + }
>>> +
>>> + return ret;
>>> +err:
>>> + cdns3_exit_roles(cdns);
>>> + return ret;
>>> +}
>>> +
>>> +/**
>>> + * cdsn3_get_real_role - get real role of controller based on hardware settings.
>>> + * @cdns: Pointer to cdns3 structure
>>> + *
>>> + * Returns role
>>> + */
>>> +enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns)
>>> +{
>>> + enum cdns3_roles role = CDNS3_ROLE_END;
>>> +
>>> + if (cdns->current_dr_mode == USB_DR_MODE_OTG) {
>>> + if (cdns3_get_id(cdns))
>>> + role = CDNS3_ROLE_GADGET;
>>> + else
>>> + role = CDNS3_ROLE_HOST;
>>> + } else {
>>> + if (cdns3_is_host(cdns))
>>> + role = CDNS3_ROLE_HOST;
>>> + if (cdns3_is_device(cdns))
>>> + role = CDNS3_ROLE_GADGET;
>>> + }
>>> +
>>> + return role;
>>> +}
>>> +
>>> +/**
>>> + * cdns3_role_switch - work queue handler for role switch
>>> + *
>>> + * @work: work queue item structure
>>> + *
>>> + * Handles below events:
>>> + * - Role switch for dual-role devices
>>> + * - CDNS3_ROLE_GADGET <--> CDNS3_ROLE_END for peripheral-only devices
>>> + */
>>> +static void cdns3_role_switch(struct work_struct *work)
>>> +{
>>> + enum cdns3_roles role = CDNS3_ROLE_END;
>>> + struct cdns3_role_driver *role_drv;
>>> + enum cdns3_roles current_role;
>>> + struct cdns3 *cdns;
>>> + int ret = 0;
>>> +
>>> + cdns = container_of(work, struct cdns3, role_switch_wq);
>>> +
>>> + /* During switching cdns->role can be different then role */
>>> + role = cdsn3_get_real_role(cdns);
>>> +
>>> + role_drv = cdns3_get_current_role_driver(cdns);
>>> +
>>> + pm_runtime_get_sync(cdns->dev);
>>> +
>>> + /* Disable current role. This state can be forced from user space. */
>>> + if (cdns->debug_disable && role_drv->state == CDNS3_ROLE_STATE_ACTIVE) {
>>> + cdns3_role_stop(cdns);
>>> + goto exit;
>>> + }
>>> +
>>> + /* Do nothing if nothing changed */
>>> + if (cdns->role == role && role_drv->state == CDNS3_ROLE_STATE_ACTIVE)
>>> + goto exit;
>>> +
>>> + cdns3_role_stop(cdns);
>>> +
>>> + role = cdsn3_get_real_role(cdns);
>>> +
>>> + current_role = cdns->role;
>>> + dev_dbg(cdns->dev, "Switching role");
>>> +
>>> + ret = cdns3_role_start(cdns, role);
>>> + if (ret) {
>>> + /* Back to current role */
>>> + dev_err(cdns->dev, "set %d has failed, back to %d\n",
>>> + role, current_role);
>>> + cdns3_role_start(cdns, current_role);
>>> + }
>>> +exit:
>>> + pm_runtime_put_sync(cdns->dev);
>>> +}
>>> +
>>> +/**
>>> + * cdns3_probe - probe for cdns3 core device
>>> + * @pdev: Pointer to cdns3 core platform device
>>> + *
>>> + * Returns 0 on success otherwise negative errno
>>> + */
>>> +static int cdns3_probe(struct platform_device *pdev)
>>> +{
>>> + struct device *dev = &pdev->dev;
>>> + struct resource *res;
>>> + struct cdns3 *cdns;
>>> + void __iomem *regs;
>>> + int ret;
>>> +
>>> + cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
>>> + if (!cdns)
>>> + return -ENOMEM;
>>> +
>>> + cdns->dev = dev;
>>> +
>>> + platform_set_drvdata(pdev, cdns);
>>> +
>>> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>>> + if (!res) {
>>> + dev_err(dev, "missing IRQ\n");
>>> + return -ENODEV;
>>> + }
>>> + cdns->irq = res->start;
>>> +
>>> + cdns->xhci_res[0] = *res;
>>> +
>>> + /*
>>> + * Request memory region
>>> + * region-0: xHCI
>>> + * region-1: Peripheral
>>> + * region-2: OTG registers
>>> + */
>>the comment should be modified or removed if not necessary when codes
>>changed.
>
>Yes, now it's not necessary.
>
>>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
>>> + if (!res)
>>> + return -ENXIO;
>>> +
>>> + cdns->xhci_res[1] = *res;
>>> +
>>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
>>> + regs = devm_ioremap_resource(dev, res);
>>> + if (IS_ERR(regs))
>>> + return PTR_ERR(regs);
>>> + cdns->dev_regs = regs;
>>> +
>>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
>>> + if (!res)
>>> + return -ENXIO;
>>> +
>>> + cdns->otg_res = *res;
>>> +
>>> + mutex_init(&cdns->mutex);
>>> +
>>> + cdns->phy = devm_phy_optional_get(dev, "cdns3,usbphy");
>>> + if (IS_ERR(cdns->phy))
>>> + return PTR_ERR(cdns->phy);
>>> +
>>> + phy_init(cdns->phy);
>>check the return value? and
>>It's better to call phy_power_on() here even if the phy driver doesn't
>>provide power_on()
>
>Driver doesn't need to check return value in this case. It was discussed some time ago.
>
>>
>>> +
>>> + INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
>>> +
>>> + ret = cdns3_drd_init(cdns);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + ret = cdns3_core_init_role(cdns);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + cdns3_debugfs_init(cdns);
>>> + device_set_wakeup_capable(dev, true);
>>> + pm_runtime_set_active(dev);
>>> + pm_runtime_enable(dev);
>>> +
>>> + /*
>>> + * The controller needs less time between bus and controller suspend,
>>> + * and we also needs a small delay to avoid frequently entering low
>>> + * power mode.
>>> + */
>>> + pm_runtime_set_autosuspend_delay(dev, 20);
>>> + pm_runtime_mark_last_busy(dev);
>>> + pm_runtime_use_autosuspend(dev);
>>> + dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
>>> +
>>> + return 0;
>>> +
>>> +err:
>>> + phy_exit(cdns->phy);
>>> + return ret;
>>> +}
>>> +
>>> +/**
>>> + * cdns3_remove - unbind drd driver and clean up
>>> + * @pdev: Pointer to Linux platform device
>>> + *
>>> + * Returns 0 on success otherwise negative errno
>>> + */
>>> +static int cdns3_remove(struct platform_device *pdev)
>>> +{
>>> + struct cdns3 *cdns = platform_get_drvdata(pdev);
>>> +
>>> + pm_runtime_get_sync(&pdev->dev);
>>> + pm_runtime_disable(&pdev->dev);
>>> + pm_runtime_put_noidle(&pdev->dev);
>>> + cdns3_debugfs_exit(cdns);
>>> + cdns3_exit_roles(cdns);
>>> + phy_exit(cdns->phy);
>>> + 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 <pawell@xxxxxxxxxxx>");
>>> +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@xxxxxxx>
>>> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
>>> + */
>>> +#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
>>no irq member,
>>> + * @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
>>not pointer
>
>Why ?
>struct cdns3_otg_common_regs *otg_regs;
>
>But I forgot:
> * @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
>
>>> + * @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;
>>Does the single phy support both HS and SS?
>>> + 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@xxxxxxxxxxx>
>>> + */
>>> +#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@xxxxxxxxxxx>
>>> + */
>>> +
>>> +#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;
>>> + cdns3_role_stop(cdns);
>>> + cdns3_drd_update_mode(cdns);
>>> + 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);
>>> +}
>>> 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@xxxxxxxxxxx
>>> + *
>>> + */
>>> +#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");
>>> + ret = cdns3_drd_switch_gadget(cdns, 1);
>>> + break;
>>> + case USB_DR_MODE_HOST:
>>> + dev_info(cdns->dev, "Set controller to Host mode\n");
>>> + ret = cdns3_drd_switch_host(cdns, 1);
>>> + break;
>>> + case USB_DR_MODE_OTG:
>>> + dev_info(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_is_host(struct cdns3 *cdns)
>>maybe it's better to use bool instead of int
>>> +{
>>> + 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)
>>ditto
>>> +{
>>> + 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
>>> + */
>>[...]
>>> +DEFINE_EVENT(cdns3_log_request_handled, cdns3_request_handled,
>>> + TP_PROTO(struct cdns3_request *priv_req, int current_index,
>>> + int handled),
>>> + TP_ARGS(priv_req, current_index, handled)
>>> +);
>>> +#endif /* __LINUX_CDNS3_TRACE */
>>> +
>>> +/* this part must be outside header guard */
>>> +
>>> +#undef TRACE_INCLUDE_PATH
>>> +#define TRACE_INCLUDE_PATH .
>>> +
>>> +#undef TRACE_INCLUDE_FILE
>>> +#define TRACE_INCLUDE_FILE trace
>>> +
>>> +#include <trace/define_trace.h>
>>
>Thanks,
>Pawel