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SubjectRE: [PATCH v2 5/5] usb:cdns3 Add Cadence USB3 DRD Driver
Date
Hi

>On Sun, 2018-12-23 at 15:13 +0000, Pawel Laszczak wrote:
>> This patch introduce new Cadence USBSS DRD driver
>> to linux kernel.
>
><...>
>
>> diff --git a/drivers/usb/cdns3/cdns3-pci-wrap.c b/drivers/usb/cdns3/cdns3-pci-wrap.c
>> new file mode 100644
>> index 000000000000..e93179c45ece
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/cdns3-pci-wrap.c
>> @@ -0,0 +1,157 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS PCI Glue driver
>> + *
>> + * Copyright (C) 2018 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[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 = "cdns3-dev-regs";
>> + 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 = "cdns3-xhci-regs";
>> + 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 = "cdns3-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)) {
>> + err = PTR_ERR(wrap->plat_dev);
>> + return err;
>> + }
>return PTR_ERR(wrap->plat_dev);
Ok.
>
>> +
>> + 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@cadence.com>");
>> +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..d274586aca36
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/core.c
>> @@ -0,0 +1,406 @@
>> +// 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 inline int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
>remove inline
Ok.

>> +{
>> + 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);
>Do you need check ret value? if not, no need assign it

I will add checking.
>> +
>> + 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);
>> +
>remove blank line
>> + 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
>> + */
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + cdns->xhci_res[1] = *res;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>> + regs = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(regs))
>> + return PTR_ERR(regs);
>> + cdns->dev_regs = regs;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
>> + cdns->otg_res = *res;
>It'll make the DTS clearer if add reg-names

Good Idea. I assume that in this case regs-names will be mandatory property and
I have to replace platform_get_resource with platform_get_resource_byname.
Also I have to made some changes in cdns3-pci-wrap.c file.

>> +
>> + mutex_init(&cdns->mutex);
>> +
>> + cdns->phy = devm_phy_get(dev, "cdns3,usbphy");
>Try to use devm_phy_optional_get()?

Ok, so the code will look like:
cdns->phy = devm_phy_optional_get(dev, "cdns3,usbphy");
if (IS_ERR(cdns->phy) )
return PTR_ERR(cdns->phy);

>> + if (IS_ERR(cdns->phy)) {
>> + ret = PTR_ERR(cdns->phy);
>> + if (ret == -ENODEV) {
>> + cdns->phy = NULL;
>> + } else if (ret == -EPROBE_DEFER) {
>> + return ret;
>> + } else {
>> + dev_err(dev, "no phy found\n");
>> + goto err0;
>> + }
>> + }
>> +
>> + phy_init(cdns->phy);
>> +
>> + INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
>> +
>> + ret = cdns3_drd_init(cdns);
>> + if (ret)
>> + goto err1;
>> +
>> + ret = cdns3_core_init_role(cdns);
>> + if (ret)
>> + goto err1;
>> +
>> + 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;
>> +
>> +err1:
>> + phy_exit(cdns->phy);
>> +err0:
>> + 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@cadence.com>");
>> +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..94f9ef15f899
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debug.h
>> @@ -0,0 +1,166 @@
>> +/* 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,
>> +
>too many sentences as inline function
>> 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)
>ditto
>> +{
>> + 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)
>ditto
>> +{
>> + 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;
>> +}
>> +
>> +#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..d7919f5c1d90
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debugfs.c
>> @@ -0,0 +1,168 @@
>> +// 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;
>> + 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;
>> + int disable;
>> + char buf[32];
>> +
>> + if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
>> + return -EFAULT;
>> +
>> + if (!strncmp(buf, "1", 1) || !strncmp(buf, "yes", 3)) {
>> + disable = 1;
>> + } else if (!strncmp(buf, "0", 1) || !strncmp(buf, "no", 2)) {
>> + disable = 0;
>> + } else {
>> + dev_err(cdns->dev, "Failed: incorrect disable setting\n");
>> + return -EFAULT;
>> + }
>> +
>There is common API kstrtobool()?
Ok, much simpler.
>> + 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..b0c32302eb0b
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/drd.c
>> @@ -0,0 +1,350 @@
>> +// 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
>> + */
>> +void cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
>> +{
>> + u32 reg;
>> +
>> + cdns->current_dr_mode = mode;
>> +
>> + switch (mode) {
>> + case USB_DR_MODE_PERIPHERAL:
>> + dev_info(cdns->dev, "Set controller to Gadget mode\n");
>> + cdns3_drd_switch_gadget(cdns, 1);
>> + break;
>> + case USB_DR_MODE_HOST:
>> + dev_info(cdns->dev, "Set controller to Host mode\n");
>> + 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;
>> + }
>> +}
>> +
>> +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 1 ; //id;
>return fixed value ?

My mistake. I forgot to restore this.
It should be "return id" .
I thought that checkpatch remained me about this :).
Thanks.

>> +}
>> +
>> +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;
>> +}
>> +
>> +
>
>> +
>> +/**
>> + * cdns3_init_otg_mode - initialize drd controller
>> + * @cdns: Pointer to controller context structure
>> + *
>> + * Returns 0 on success otherwise negative errno
>void function
It should be int.
>> + */
>> +static void cdns3_init_otg_mode(struct cdns3 *cdns)
>> +{
>> + cdns3_otg_disable_irq(cdns);
>> + /* clear all interrupts */
>> + writel(~0, &cdns->otg_regs->ivect);
>> +
>> + cdns3_set_mode(cdns, USB_DR_MODE_OTG);
>> +
>> + if (cdns3_is_host(cdns))
>> + cdns3_drd_switch_host(cdns, 1);
>> + else
>> + cdns3_drd_switch_gadget(cdns, 1);
>> +
>> + cdns3_otg_enable_irq(cdns);
>> +}
>> +
>> +/**
>> + * 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;
>> +
>> + cdns3_drd_switch_gadget(cdns, 0);
>> + cdns3_drd_switch_host(cdns, 0);
>> +
>> + switch (cdns->desired_dr_mode) {
>> + case USB_DR_MODE_PERIPHERAL:
>> + cdns3_set_mode(cdns, USB_DR_MODE_PERIPHERAL);
>> + break;
>> + case USB_DR_MODE_HOST:
>> + cdns3_set_mode(cdns, USB_DR_MODE_HOST);
>> + break;
>> + case USB_DR_MODE_OTG:
>> + cdns3_init_otg_mode(cdns);
>> + break;
>> + default:
>> + dev_err(cdns->dev, "Unsupported mode of operation %d\n",
>> + cdns->dr_mode);
>> + return -EINVAL;
>> + }
>> +
>> + return ret;
>no need define local variable @ret

It will keep return value from cdns3_set_mode and cdns3_init_otg_mode functions.
>> +}
>> +
>> +/**
>> + * 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));
>> +
>> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
>> +
>do you need to clear interrupts status here?
It's the best place for clearing interrupt. Driver enables only detection id changes.
We can read ID status also from OTG status register. Even if driver lost some events it will
not be a problem.

>> + ret = IRQ_HANDLED;
>> + }
>> +
>> + 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;
>> + 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;
>> + 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_info(cdns->dev, "Controller strapped to HOST\n");
>> + cdns->dr_mode = USB_DR_MODE_HOST;
>> + } else if (state == OTGSTS_STRAP_GADGET) {
>> + dev_info(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->irq, cdns3_drd_irq,
>> + NULL, IRQF_SHARED,
>> + dev_name(cdns->dev), cdns);
>> +
>> + if (ret)
>> + 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;
>> + }
>> +
>> + ret = cdns3_drd_update_mode(cdns);
>> +
>> + return ret;
>return cdns3_drd_update_mode();
>> +}
>> +
>> +int cdns3_drd_exit(struct cdns3 *cdns)
>> +{
>> + return cdns3_drd_switch_host(cdns, 0);
>> +}
>
>
><...>
>
>> diff --git a/drivers/usb/cdns3/ep0.c b/drivers/usb/cdns3/ep0.c
>> new file mode 100644
>> index 000000000000..89cf1cde1555
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/ep0.c
>> @@ -0,0 +1,896 @@
>> +// 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>
>> + */
>> +
>> +#include <linux/usb/composite.h>
>> +
>> +#include "gadget.h"
>> +#include "trace.h"
>> +
>> +static struct usb_endpoint_descriptor cdns3_gadget_ep0_desc = {
>> + .bLength = USB_DT_ENDPOINT_SIZE,
>> + .bDescriptorType = USB_DT_ENDPOINT,
>> + .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
>> +};
>> +
><...>
>> +
>> +
>> +#endif /* __LINUX_CDNS3_GADGET_EXPORT */
>> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
>> new file mode 100644
>> index 000000000000..0d95eb00be37
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/gadget.c
>> @@ -0,0 +1,2102 @@
>> +// 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>
>> + */
>> +
>> +#include <linux/dma-mapping.h>
>> +#include <linux/usb/gadget.h>
>> +
><...>
>
>> +/**
>> + * cdns3_next_request - returns next request from list
>> + * @list: list containing requests
>> + *
>> + * Returns request or NULL if no requests in list
>> + */
>> +struct usb_request *cdns3_next_request(struct list_head *list)
>> +{
>> + if (list_empty(list))
>> + return NULL;
>No need check it, if list is empty, list_first_entry_or_null() will
>return NULL
Ok,

>> + return list_first_entry_or_null(list, struct usb_request, list);
>> +}
>> +
>> +/**
>> + * cdns3_next_priv_request - returns next request from list
>> + * @list: list containing requests
>> + *
>> + * Returns request or NULL if no requests in list
>> + */
>> +struct cdns3_request *cdns3_next_priv_request(struct list_head *list)
>> +{
>> + if (list_empty(list))
>> + return NULL;
>ditto
>> + return list_first_entry_or_null(list, struct cdns3_request, list);
>> +}
>> +
>
><...>
>
Thanks for comments.
Cheers,
Pawel

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