RE: [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver

[Pawel Laszczak <pawell@cadence.com>]

Hi Felipe,

>
>Hi,
>
>Pawel Laszczak <pawell@cadence.com> writes:
>> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
>> new file mode 100644
>> index 000000000000..ddc73f1c87c5
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/core.c
>> @@ -0,0 +1,543 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS DRD Driver.
>> + *
>> + * Copyright (C) 2018-2019 Cadence.
>> + * Copyright (C) 2017-2018 NXP
>> + * Copyright (C) 2019 Texas Instruments
>> + *
>> + * Author: Peter Chen <peter.chen@nxp.com>
>> + *         Pawel Laszczak <pawell@cadence.com>
>> + *         Roger Quadros <rogerq@ti.com>
>> + */
>> +
>> +#include <linux/dma-mapping.h>
>> +#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"
>> +
>> +/**
>> + * cdns3_handshake - spin reading  until handshake completes or fails
>> + * @ptr: address of device controller register to be read
>> + * @mask: bits to look at in result of read
>> + * @done: value of those bits when handshake succeeds
>> + * @usec: timeout in microseconds
>> + *
>> + * Returns negative errno, or zero on success
>> + *
>> + * Success happens when the "mask" bits have the specified value (hardware
>> + * handshake done). There are two failure modes: "usec" have passed (major
>> + * hardware flakeout), or the register reads as all-ones (hardware removed).
>> + */
>> +int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
>> +{
>> +	u32 result;
>> +
>> +	do {
>> +		result = readl(ptr);
>> +		if (result == ~(u32)0)  /* card removed */
>> +			return -ENODEV;
>> +
>> +		result &= mask;
>> +		if (result == done)
>> +			return 0;
>> +
>> +		udelay(1);
>> +		usec--;
>> +	} while (usec > 0);
>> +
>> +	return -ETIMEDOUT;
>
>looks like readl_poll_timeout_atomic() would handle this.
>

Actually, it works the same. I'm going to use it instead cdns3_handshake.

>> +}
>> +
>> +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)
>
>not static? Why is it so that _start() is static but _stop() is not?
>Looks fishy

This function is used in cdns3_role_stop in debugfs.c file so it can't  be static.

>> +{
>> +	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);
>> +}
>> +
>> +static void cdns3_exit_roles(struct cdns3 *cdns)
>> +{
>> +	cdns3_role_stop(cdns);
>> +	cdns3_drd_exit(cdns);
>> +}
>> +
>> +enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns);
>> +
>> +static int cdns3_idle_role_start(struct cdns3 *cnds)
>> +{	/* Hold PHY in RESET */
>
>huh?
>
>> +	return 0;
>> +}
>> +
>> +static void cdns3_idle_role_stop(struct cdns3 *cnds)
>> +{
>> +	/* Program Lane swap and bring PHY out of RESET */
>
>double huh?
>

These functions were added for consistency with FSM described in controller specification. 
Yes, I know that you don't like empty functions :), but it could be helpful in
understanding how this controller work.

>> +}
>> +
>> +static int cdns3_idle_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_idle_role_start;
>> +	rdrv->stop = cdns3_idle_role_stop;
>> +	rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
>> +	rdrv->suspend = NULL;
>> +	rdrv->resume = NULL;
>> +	rdrv->name = "idle";
>
>why don't you use the mux framework for this? This looks a bit fishy
>too. Why do you have your own driver registration structure for your
>driver only?
>

I assume you mean interface defined in include/linux/usb/role.h.
It's quite new framework and probably was added after I've start implementing cdns3 driver.  
At first glance it's look that I could use it.

>> +
>> +	cdns->roles[CDNS3_ROLE_IDLE] = rdrv;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * 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_mode 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;
>> +	}
>> +
>> +	/*
>> +	 * At this point cdns->dr_mode contains strap configuration.
>> +	 * Driver try update this setting considering kernel configuration
>> +	 */
>> +	best_dr_mode = cdns->dr_mode;
>> +
>> +	ret = cdns3_idle_init(cdns);
>> +	if (ret)
>> +		return ret;
>> +
>> +	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;
>> +
>> +	/*
>> +	 * desired_dr_mode might have changed so we need to update
>> +	 * the controller configuration"?
>> +	 */
>> +	ret = cdns3_drd_update_mode(cdns);
>> +	if (ret)
>> +		goto err;
>> +
>> +	cdns->role = cdsn3_get_real_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;
>> +	int id, vbus;
>> +
>> +	if (cdns->current_dr_mode != USB_DR_MODE_OTG)
>> +		goto not_otg;
>> +
>> +	id = cdns3_get_id(cdns);
>> +	vbus = cdns3_get_vbus(cdns);
>> +
>> +	/*
>> +	 * Role change state machine
>> +	 * Inputs: ID, VBUS
>> +	 * Previous state: cdns->role
>> +	 * Next state: role
>> +	 */
>> +	role = cdns->role;
>> +
>> +	switch (role) {
>> +	case CDNS3_ROLE_IDLE: /* from IDLE, we can change to HOST or GADGET */
>> +		if (!id)
>> +			role = CDNS3_ROLE_HOST;
>> +		else if (vbus)
>> +			role = CDNS3_ROLE_GADGET;
>> +		break;
>> +	case CDNS3_ROLE_HOST: /* from HOST, we can only change to IDLE */
>> +		if (id)
>> +			role = CDNS3_ROLE_IDLE;
>> +		break;
>> +	case CDNS3_ROLE_GADGET: /* from GADGET, we can only change to IDLE */
>> +		if (!vbus)
>> +			role = CDNS3_ROLE_IDLE;
>> +		break;
>> +	case CDNS3_ROLE_END: /* only at initialization, move to IDLE */
>> +		role = CDNS3_ROLE_IDLE;
>> +		break;
>> +	}
>> +
>> +	dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
>> +
>> +	return role;
>> +
>> +not_otg:
>> +	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);
>> +
>> +	pm_runtime_get_sync(cdns->dev);
>> +
>> +	role = cdsn3_get_real_role(cdns);
>> +
>> +	role_drv = cdns3_get_current_role_driver(cdns);
>> +
>> +	/* Disable current role if requested from debugfs */
>> +	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);
>> +		ret = cdns3_role_start(cdns, current_role);
>> +		if (ret)
>> +			dev_err(cdns->dev, "back to %d failed too\n",
>> +				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;
>> +
>> +	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
>> +	if (ret) {
>> +		dev_err(dev, "error setting dma mask: %d\n", ret);
>> +		return -ENODEV;
>> +	}
>> +
>> +	cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
>> +	if (!cdns)
>> +		return -ENOMEM;
>> +
>> +	cdns->dev = dev;
>> +
>> +	platform_set_drvdata(pdev, cdns);
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "host");
>> +	if (!res) {
>> +		dev_err(dev, "missing host IRQ\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	cdns->xhci_res[0] = *res;
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
>> +	if (!res) {
>> +		dev_err(dev, "couldn't get xhci resource\n");
>> +		return -ENXIO;
>> +	}
>> +
>> +	cdns->xhci_res[1] = *res;
>> +
>> +	cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
>> +	if (cdns->dev_irq == -EPROBE_DEFER)
>> +		return cdns->dev_irq;
>> +
>> +	if (cdns->dev_irq < 0)
>> +		dev_err(dev, "couldn't get peripheral irq\n");
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
>> +	regs = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(regs)) {
>> +		dev_err(dev, "couldn't iomap dev resource\n");
>> +		return PTR_ERR(regs);
>> +	}
>> +	cdns->dev_regs	= regs;
>> +
>> +	cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
>> +	if (cdns->otg_irq == -EPROBE_DEFER)
>> +		return cdns->otg_irq;
>> +
>> +	if (cdns->otg_irq < 0) {
>> +		dev_err(dev, "couldn't get otg irq\n");
>> +		return cdns->otg_irq;
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
>> +	if (!res) {
>> +		dev_err(dev, "couldn't get otg resource\n");
>> +		return -ENXIO;
>> +	}
>> +
>> +	cdns->otg_res = *res;
>> +
>> +	mutex_init(&cdns->mutex);
>> +
>> +	cdns->usb2_phy = devm_phy_optional_get(dev, "cdns3,usb2-phy");
>> +	if (IS_ERR(cdns->usb2_phy))
>> +		return PTR_ERR(cdns->usb2_phy);
>> +
>> +	phy_init(cdns->usb2_phy);
>> +	ret = phy_init(cdns->usb2_phy);
>> +	if (ret)
>> +		return ret;
>> +
>> +	cdns->usb3_phy = devm_phy_optional_get(dev, "cdns3,usb3-phy");
>> +	if (IS_ERR(cdns->usb3_phy))
>> +		return PTR_ERR(cdns->usb3_phy);
>> +
>> +	phy_init(cdns->usb3_phy);
>> +	ret = phy_init(cdns->usb3_phy);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = phy_power_on(cdns->usb2_phy);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = phy_power_on(cdns->usb3_phy);
>> +	if (ret)
>> +		goto err1;
>> +
>> +	INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
>> +
>> +	ret = cdns3_drd_init(cdns);
>> +	if (ret)
>> +		goto err2;
>> +
>> +	ret = cdns3_core_init_role(cdns);
>> +	if (ret)
>> +		goto err2;
>> +
>> +	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;
>> +
>> +err2:
>> +	phy_power_off(cdns->usb3_phy);
>> +
>> +err1:
>> +	phy_power_off(cdns->usb2_phy);
>> +	phy_exit(cdns->usb2_phy);
>> +	phy_exit(cdns->usb3_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_power_off(cdns->usb2_phy);
>> +	phy_power_off(cdns->usb3_phy);
>> +	phy_exit(cdns->usb2_phy);
>> +	phy_exit(cdns->usb3_phy);
>> +	return 0;
>> +}
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id of_cdns3_match[] = {
>> +	{ .compatible = "cdns,usb3" },
>> +	{ },
>> +};
>> +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..be95696ab17e
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/core.h
>> @@ -0,0 +1,121 @@
>> +/* 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 */
>> diff --git a/drivers/usb/cdns3/debug.h b/drivers/usb/cdns3/debug.h
>> new file mode 100644
>> index 000000000000..65c3d8a6cd62
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debug.h
>> @@ -0,0 +1,173 @@
>> +/* 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*/
>> diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
>> new file mode 100644
>> index 000000000000..44ee78a10eb8
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debugfs.c
>> @@ -0,0 +1,153 @@
>> +// 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",
>> +};
>
>don't we have a generic version of this under usb/common ?
>
Yes, there is a similar array, but it is defined also as static 
and there is no function for converting value to string. 
There is only function for converting string to value.

There is also:  
[USB_DR_MODE_UNKNOWN]		= "",
Instead of: 
[USB_DR_MODE_UNKNOWN]		= "unknown",

So, for USB_DR_MODE_UNKNOWN user will not see anything information.

>> +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);
>
>put this under usb root. I should move dwc3 there too.

Alright, I'll move it.

>
>> +	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..b06929fe1175
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/drd.c
>> @@ -0,0 +1,379 @@
>> +// 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;
>> +}
>
>seems like you could use threaded irq to avoid this workqueue.


This function is also called in cdns3_mode_write (debugfs.c file),
therefor after changing it to threaded irq I will still need workqueue. 

I will change It.

>
>> +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,
>
>if you don't have a threaded handler, you should set IRQF_ONESHOT. I
>would prefer if you implement a threaded handler that doesn't require
>IRQF_ONESHOT, though.
>

IRQF_ONESHOT can be used  only in threaded handled. 
"
 * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
 *                Used by threaded interrupts which need to keep the
 *                irq line disabled until the threaded handler has been run.
"

>> +					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;
>> +}
>> diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
>> new file mode 100644
>> index 000000000000..bf6c7bc41b58
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/drd.h
>> @@ -0,0 +1,166 @@
>> +/* 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 */
>> diff --git a/drivers/usb/cdns3/ep0.c b/drivers/usb/cdns3/ep0.c
>> new file mode 100644
>> index 000000000000..6fa711ead6d0
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/ep0.c
>> @@ -0,0 +1,920 @@
>> +// 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,
>> +};
>> +
>> +/**
>> + * cdns3_ep0_run_transfer - Do transfer on default endpoint hardware
>> + * @priv_dev: extended gadget object
>> + * @dma_addr: physical address where data is/will be stored
>> + * @length: data length
>> + * @erdy: set it to 1 when ERDY packet should be sent -
>> + *        exit from flow control state
>> + */
>> +static void cdns3_ep0_run_transfer(struct cdns3_device *priv_dev,
>> +				   dma_addr_t dma_addr,
>> +				   unsigned int length, int erdy, int zlp)
>> +{
>> +	struct cdns3_usb_regs __iomem *regs = priv_dev->regs;
>> +	struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
>> +
>> +	priv_ep->trb_pool[0].buffer = TRB_BUFFER(dma_addr);
>> +	priv_ep->trb_pool[0].length = TRB_LEN(length);
>> +
>> +	if (zlp) {
>> +		priv_ep->trb_pool[0].control = TRB_CYCLE | TRB_TYPE(TRB_NORMAL);
>> +		priv_ep->trb_pool[1].buffer = TRB_BUFFER(dma_addr);
>> +		priv_ep->trb_pool[1].length = TRB_LEN(0);
>> +		priv_ep->trb_pool[1].control = TRB_CYCLE | TRB_IOC |
>> +		    TRB_TYPE(TRB_NORMAL);
>> +	} else {
>> +		priv_ep->trb_pool[0].control = TRB_CYCLE | TRB_IOC |
>> +		    TRB_TYPE(TRB_NORMAL);
>> +		priv_ep->trb_pool[1].control = 0;
>> +	}
>> +
>> +	trace_cdns3_prepare_trb(priv_ep, priv_ep->trb_pool);
>> +
>> +	cdns3_select_ep(priv_dev, priv_dev->ep0_data_dir);
>> +
>> +	writel(EP_STS_TRBERR, &regs->ep_sts);
>> +	writel(EP_TRADDR_TRADDR(priv_ep->trb_pool_dma), &regs->ep_traddr);
>> +	trace_cdns3_doorbell_ep0(priv_dev->ep0_data_dir ? "ep0in" : "ep0out",
>> +				 readl(&regs->ep_traddr));
>> +
>> +	/* TRB should be prepared before starting transfer. */
>> +	writel(EP_CMD_DRDY, &regs->ep_cmd);
>> +
>> +	/* Resume controller before arming transfer. */
>> +	__cdns3_gadget_wakeup(priv_dev);
>> +
>> +	if (erdy)
>> +		writel(EP_CMD_ERDY, &priv_dev->regs->ep_cmd);
>> +}
>> +
>> +/**
>> + * cdns3_ep0_delegate_req - Returns status of handling setup packet
>> + * Setup is handled by gadget driver
>> + * @priv_dev: extended gadget object
>> + * @ctrl_req: pointer to received setup packet
>> + *
>> + * Returns zero on success or negative value on failure
>> + */
>> +static int cdns3_ep0_delegate_req(struct cdns3_device *priv_dev,
>> +				  struct usb_ctrlrequest *ctrl_req)
>> +{
>> +	int ret;
>> +
>> +	spin_unlock(&priv_dev->lock);
>> +	priv_dev->setup_pending = 1;
>> +	ret = priv_dev->gadget_driver->setup(&priv_dev->gadget, ctrl_req);
>> +	priv_dev->setup_pending = 0;
>> +	spin_lock(&priv_dev->lock);
>> +	return ret;
>> +}
>> +
>> +static void cdns3_prepare_setup_packet(struct cdns3_device *priv_dev)
>> +{
>> +	priv_dev->ep0_data_dir = 0;
>> +	priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
>> +	cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
>> +			       sizeof(struct usb_ctrlrequest), 0, 0);
>> +}
>> +
>> +static void cdns3_ep0_complete_setup(struct cdns3_device *priv_dev,
>> +				     u8 send_stall, u8 send_erdy)
>> +{
>> +	struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
>> +	struct usb_request *request;
>> +
>> +	request = cdns3_next_request(&priv_ep->pending_req_list);
>> +	if (request)
>> +		list_del_init(&request->list);
>> +
>> +	if (send_stall) {
>> +		cdns3_dbg(priv_ep->cdns3_dev, "STALL for ep0\n");
>> +		/* set_stall on ep0 */
>> +		cdns3_select_ep(priv_dev, 0x00);
>> +		writel(EP_CMD_SSTALL, &priv_dev->regs->ep_cmd);
>> +	} else {
>> +		cdns3_prepare_setup_packet(priv_dev);
>> +	}
>> +
>> +	priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
>> +	writel((send_erdy ? EP_CMD_ERDY : 0) | EP_CMD_REQ_CMPL,
>> +	       &priv_dev->regs->ep_cmd);
>> +
>> +	cdns3_allow_enable_l1(priv_dev, 1);
>> +}
>> +
>> +/**
>> + * cdns3_req_ep0_set_configuration - Handling of SET_CONFIG standard USB request
>> + * @priv_dev: extended gadget object
>> + * @ctrl_req: pointer to received setup packet
>> + *
>> + * Returns 0 if success, USB_GADGET_DELAYED_STATUS on deferred status stage,
>> + * error code on error
>> + */
>> +static int cdns3_req_ep0_set_configuration(struct cdns3_device *priv_dev,
>> +					   struct usb_ctrlrequest *ctrl_req)
>> +{
>> +	enum usb_device_state device_state = priv_dev->gadget.state;
>> +	struct cdns3_endpoint *priv_ep;
>> +	u32 config = le16_to_cpu(ctrl_req->wValue);
>> +	int result = 0;
>> +	int i;
>> +
>> +	switch (device_state) {
>> +	case USB_STATE_ADDRESS:
>> +		/* Configure non-control EPs */
>> +		for (i = 0; i < CDNS3_ENDPOINTS_MAX_COUNT; i++) {
>> +			priv_ep = priv_dev->eps[i];
>> +			if (!priv_ep)
>> +				continue;
>> +
>> +			if (priv_ep->flags & EP_CLAIMED)
>> +				cdns3_ep_config(priv_ep);
>> +		}
>> +
>> +		result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
>> +
>> +		if (result)
>> +			return result;
>> +
>> +		if (config) {
>> +			cdns3_set_hw_configuration(priv_dev);
>> +		} else {
>> +			cdns3_hw_reset_eps_config(priv_dev);
>> +			usb_gadget_set_state(&priv_dev->gadget,
>> +					     USB_STATE_ADDRESS);
>> +		}
>> +		break;
>> +	case USB_STATE_CONFIGURED:
>> +		result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
>> +
>> +		if (!config && !result) {
>> +			cdns3_hw_reset_eps_config(priv_dev);
>> +			usb_gadget_set_state(&priv_dev->gadget,
>> +					     USB_STATE_ADDRESS);
>> +		}
>> +		break;
>> +	default:
>> +		result = -EINVAL;
>> +	}
>> +
>> +	return result;
>> +}
>> +
>> +/**
>> + * cdns3_req_ep0_set_address - Handling of SET_ADDRESS standard USB request
>> + * @priv_dev: extended gadget object
>> + * @ctrl_req: pointer to received setup packet
>> + *
>> + * Returns 0 if success, error code on error
>> + */
>> +static int cdns3_req_ep0_set_address(struct cdns3_device *priv_dev,
>> +				     struct usb_ctrlrequest *ctrl_req)
>> +{
>> +	enum usb_device_state device_state = priv_dev->gadget.state;
>> +	u32 reg;
>> +	u32 addr;
>> +
>> +	addr = le16_to_cpu(ctrl_req->wValue);
>> +
>> +	if (addr > USB_DEVICE_MAX_ADDRESS) {
>> +		dev_err(priv_dev->dev,
>> +			"Device address (%d) cannot be greater than %d\n",
>> +			addr, USB_DEVICE_MAX_ADDRESS);
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (device_state == USB_STATE_CONFIGURED) {
>> +		dev_err(priv_dev->dev,
>> +			"can't set_address from configured state\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	reg = readl(&priv_dev->regs->usb_cmd);
>> +
>> +	writel(reg | USB_CMD_FADDR(addr) | USB_CMD_SET_ADDR,
>> +	       &priv_dev->regs->usb_cmd);
>> +
>> +	usb_gadget_set_state(&priv_dev->gadget,
>> +			     (addr ? USB_STATE_ADDRESS : USB_STATE_DEFAULT));
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * cdns3_req_ep0_get_status - Handling of GET_STATUS standard USB request
>> + * @priv_dev: extended gadget object
>> + * @ctrl_req: pointer to received setup packet
>> + *
>> + * Returns 0 if success, error code on error
>> + */
>> +static int cdns3_req_ep0_get_status(struct cdns3_device *priv_dev,
>> +				    struct usb_ctrlrequest *ctrl)
>> +{
>> +	__le16 *response_pkt;
>> +	u16 usb_status = 0;
>> +	u32 recip;
>> +	u32 reg;
>> +
>> +	recip = ctrl->bRequestType & USB_RECIP_MASK;
>> +
>> +	switch (recip) {
>> +	case USB_RECIP_DEVICE:
>> +		/* self powered */
>> +		if (priv_dev->is_selfpowered)
>> +			usb_status = BIT(USB_DEVICE_SELF_POWERED);
>> +
>> +		if (priv_dev->wake_up_flag)
>> +			usb_status |= BIT(USB_DEVICE_REMOTE_WAKEUP);
>> +
>> +		if (priv_dev->gadget.speed != USB_SPEED_SUPER)
>> +			break;
>> +
>> +		reg = readl(&priv_dev->regs->usb_sts);
>> +
>> +		if (priv_dev->u1_allowed)
>> +			usb_status |= BIT(USB_DEV_STAT_U1_ENABLED);
>> +
>> +		if (priv_dev->u2_allowed)
>> +			usb_status |= BIT(USB_DEV_STAT_U2_ENABLED);
>> +
>> +		break;
>> +	case USB_RECIP_INTERFACE:
>> +		return cdns3_ep0_delegate_req(priv_dev, ctrl);
>> +	case USB_RECIP_ENDPOINT:
>> +		/* check if endpoint is stalled */
>> +		cdns3_select_ep(priv_dev, ctrl->wIndex);
>> +		if (EP_STS_STALL(readl(&priv_dev->regs->ep_sts)))
>> +			usb_status =  BIT(USB_ENDPOINT_HALT);
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	response_pkt = (__le16 *)priv_dev->setup_buf;
>> +	*response_pkt = cpu_to_le16(usb_status);
>> +
>> +	cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
>> +			       sizeof(*response_pkt), 1, 0);
>> +	return 0;
>> +}
>> +
>> +static int cdns3_ep0_feature_handle_device(struct cdns3_device *priv_dev,
>> +					   struct usb_ctrlrequest *ctrl,
>> +					   int set)
>> +{
>> +	enum usb_device_state state;
>> +	enum usb_device_speed speed;
>> +	int ret = 0;
>> +	u32 wValue;
>> +	u32 wIndex;
>> +	u16 tmode;
>> +
>> +	wValue = le16_to_cpu(ctrl->wValue);
>> +	wIndex = le16_to_cpu(ctrl->wIndex);
>> +	state = priv_dev->gadget.state;
>> +	speed = priv_dev->gadget.speed;
>> +
>> +	switch (ctrl->wValue) {
>> +	case USB_DEVICE_REMOTE_WAKEUP:
>> +		priv_dev->wake_up_flag = !!set;
>> +		break;
>> +	case USB_DEVICE_U1_ENABLE:
>> +		if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
>> +			return -EINVAL;
>> +
>> +		priv_dev->u1_allowed = !!set;
>> +		break;
>> +	case USB_DEVICE_U2_ENABLE:
>> +		if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
>> +			return -EINVAL;
>> +
>> +		priv_dev->u2_allowed = !!set;
>> +		break;
>> +	case USB_DEVICE_LTM_ENABLE:
>> +		ret = -EINVAL;
>> +		break;
>> +	case USB_DEVICE_TEST_MODE:
>> +		if (state != USB_STATE_CONFIGURED || speed > USB_SPEED_HIGH)
>> +			return -EINVAL;
>> +
>> +		tmode = le16_to_cpu(ctrl->wIndex);
>> +
>> +		if (!set || (tmode & 0xff) != 0)
>> +			return -EINVAL;
>> +
>> +		switch (tmode >> 8) {
>> +		case TEST_J:
>> +		case TEST_K:
>> +		case TEST_SE0_NAK:
>> +		case TEST_PACKET:
>> +			cdns3_ep0_complete_setup(priv_dev, 0, 1);
>> +			/**
>> +			 *  Little delay to give the controller some time
>> +			 * for sending status stage.
>> +			 * This time should be less then 3ms.
>> +			 */
>> +			usleep_range(1000, 2000);
>> +			cdns3_set_register_bit(&priv_dev->regs->usb_cmd,
>> +					       USB_CMD_STMODE |
>> +					       USB_STS_TMODE_SEL(tmode - 1));
>
>I could bet this doesn't work. You're entering test mode before status
>stage. Make sure to run your driver against USB CV chapter 9 tests. You
>can use g_zero for testing.
>

We've already discussed it during review patch v5.
Status Stage in this case is send automatically by controller.
It works correct.
g_zero and CV9 are included in my set of tests and none of them is testing "Test Mode support".

>> +			break;
>> +		default:
>> +			ret = -EINVAL;
>> +		}
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdns3_ep0_feature_handle_intf(struct cdns3_device *priv_dev,
>> +					 struct usb_ctrlrequest *ctrl,
>> +					 int set)
>> +{
>> +	u32 wValue;
>> +	int ret = 0;
>> +
>> +	wValue = le16_to_cpu(ctrl->wValue);
>> +
>> +	switch (wValue) {
>> +	case USB_INTRF_FUNC_SUSPEND:
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdns3_ep0_feature_handle_endpoint(struct cdns3_device *priv_dev,
>> +					     struct usb_ctrlrequest *ctrl,
>> +					     int set)
>> +{
>> +	struct cdns3_endpoint *priv_ep;
>> +	int ret = 0;
>> +	u8 index;
>> +
>> +	if (le16_to_cpu(ctrl->wValue) != USB_ENDPOINT_HALT)
>> +		return -EINVAL;
>> +
>> +	if (!(ctrl->wIndex & ~USB_DIR_IN))
>> +		return 0;
>> +
>> +	index = cdns3_ep_addr_to_index(ctrl->wIndex);
>> +	priv_ep = priv_dev->eps[index];
>> +
>> +	cdns3_select_ep(priv_dev, ctrl->wIndex);
>> +
>> +	if (set) {
>> +		cdns3_dbg(priv_ep->cdns3_dev, "Stall endpoint %s\n",
>> +			  priv_ep->name);
>> +		writel(EP_CMD_SSTALL, &priv_dev->regs->ep_cmd);
>> +		priv_ep->flags |= EP_STALL;
>> +	} else {
>> +		struct usb_request *request;
>> +
>> +		if (priv_dev->eps[index]->flags & EP_WEDGE) {
>> +			cdns3_select_ep(priv_dev, 0x00);
>> +			return 0;
>> +		}
>> +
>> +		cdns3_dbg(priv_ep->cdns3_dev, "Clear Stalled endpoint %s\n",
>> +			  priv_ep->name);
>
>why do you need your own wrapper around dev_dbg()? This looks quite unnecessary.

It's generic function used for adding message to trace.log.  It's not wrapper to dev_dbg 

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);
}

>
>I'll stop here and review more at a later moment. Now that I had a look,
>this doesn't look ready for prime time yet.

I need some days for making all changes. 
If you could review the next part of code within 3-4 days 
I would be grateful. 

Thank for all your comments.

Cheers, 
Pawel
>
>--
>balbi