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References: <1542535751-16079-1-git-send-email-pawell@cadence.com> <1542535751-16079-5-git-send-email-pawell@cadence.com>
In-Reply-To: <1542535751-16079-5-git-send-email-pawell@cadence.com>
From:   Peter Chen <hzpeterchen@gmail.com>
Date:   Fri, 30 Nov 2018 15:32:07 +0800
Message-ID: <CAL411-rWbQ6yj1r_aaLP8UagVRJhsn7xdznQwXS9enkxXTs2LA@mail.gmail.com>
Subject: Re: [RFC PATCH v2 04/15] usb:cdns3: Driver initialization code.
To:     pawell@cadence.com
Cc:     devicetree@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, rogerq@ti.com,
        lkml <linux-kernel@vger.kernel.org>, adouglas@cadence.com,
        jbergsagel@ti.com, nsekhar@ti.com, nm@ti.com, sureshp@cadence.com,
        peter.chen@nxp.com, pjez@cadence.com, kurahul@cadence.com
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, Nov 18, 2018 at 6:16 PM Pawel Laszczak <pawell@cadence.com> wrote:
>
> Patch adds core.c and core.h file that implements initialization
> of platform driver and adds function responsible for selecting,
> switching and running appropriate Device/Host mode.
>
> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
> ---
>  drivers/usb/cdns3/Makefile |   2 +
>  drivers/usb/cdns3/core.c   | 413 +++++++++++++++++++++++++++++++++++++
>  drivers/usb/cdns3/core.h   | 100 +++++++++
>  3 files changed, 515 insertions(+)
>  create mode 100644 drivers/usb/cdns3/core.c
>  create mode 100644 drivers/usb/cdns3/core.h
>
> diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
> index dcdd62003c6a..02d25b23c5d3 100644
> --- a/drivers/usb/cdns3/Makefile
> +++ b/drivers/usb/cdns3/Makefile
> @@ -1,3 +1,5 @@
> +obj-$(CONFIG_USB_CDNS3)                        += cdns3.o
>  obj-$(CONFIG_USB_CDNS3_PCI_WRAP)       += cdns3-pci.o
>
> +cdns3-y                                        := core.o
>  cdns3-pci-y                            := cdns3-pci-wrap.o
> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
> new file mode 100644
> index 000000000000..f9055d4da67f
> --- /dev/null
> +++ b/drivers/usb/cdns3/core.c
> @@ -0,0 +1,413 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Driver.
> + *
> + * Copyright (C) 2018 Cadence.
> + *

Please add NXP copyright too.

> + * 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"
> +
> +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];
> +}
> +

Can we delete "current", and use cdns3_get_role_driver directly?

> +static inline int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
> +{
> +       int ret;
> +
> +       if (role >= CDNS3_ROLE_END)
> +               return 0;
> +
> +       if (!cdns->roles[role])
> +               return -ENXIO;
> +
> +       mutex_lock(&cdns->mutex);
> +       cdns->role = role;
> +       ret = cdns->roles[role]->start(cdns);
> +       mutex_unlock(&cdns->mutex);
> +       return ret;
> +}
> +
> +static inline void cdns3_role_stop(struct cdns3 *cdns)
> +{
> +       enum cdns3_roles role = cdns->role;
> +
> +       if (role == CDNS3_ROLE_END)
> +               return;
> +
> +       mutex_lock(&cdns->mutex);
> +       cdns->roles[role]->stop(cdns);
> +       cdns->role = CDNS3_ROLE_END;
> +       mutex_unlock(&cdns->mutex);
> +}
> +
> +static enum cdns3_roles cdns3_get_role(struct cdns3 *cdns)
> +{
> +       if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) {
> +               //TODO: implements selecting device/host mode
> +               return CDNS3_ROLE_HOST;
> +       }
> +       return cdns->roles[CDNS3_ROLE_HOST]
> +               ? CDNS3_ROLE_HOST
> +               : CDNS3_ROLE_GADGET;
> +}
> +
> +/**
> + * 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 dr_mode;
> +
> +       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;
> +       }
> +
> +       if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
> +               //TODO: implements host initialization
> +       }
> +
> +       if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
> +               //TODO: implements device initialization
> +       }
> +
> +       if (!cdns->roles[CDNS3_ROLE_HOST] && !cdns->roles[CDNS3_ROLE_GADGET]) {
> +               dev_err(dev, "no supported roles\n");
> +               return -ENODEV;
> +       }
> +
> +       cdns->dr_mode = dr_mode;
> +       return 0;
> +}
> +
> +/**
> + * cdns3_irq - interrupt handler for cdns3 core device
> + *
> + * @irq: irq number for cdns3 core device
> + * @data: structure of cdns3
> + *
> + * Returns IRQ_HANDLED or IRQ_NONE
> + */
> +static irqreturn_t cdns3_irq(int irq, void *data)
> +{
> +       struct cdns3 *cdns = data;
> +       irqreturn_t ret = IRQ_NONE;
> +
> +       /* Handle device/host interrupt */
> +       if (cdns->role != CDNS3_ROLE_END)
> +               ret = cdns3_get_current_role_driver(cdns)->irq(cdns);
> +
> +       return ret;
> +}
> +
> +static void cdns3_remove_roles(struct cdns3 *cdns)
> +{
> +       //TODO: implements this function
> +}
> +
> +static int cdns3_do_role_switch(struct cdns3 *cdns, enum cdns3_roles role)
> +{
> +       enum cdns3_roles current_role;
> +       int ret = 0;
> +
> +       current_role = cdns->role;
> +
> +       if (role == CDNS3_ROLE_END)
> +               return 0;
> +
> +       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);
> +       }
> +
> +       return ret;
> +}
> +
> +/**
> + * 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 *cdns;
> +       bool device, host;
> +
> +       cdns = container_of(work, struct cdns3, role_switch_wq);
> +
> +       //TODO: implements this functions.
> +       //host = cdns3_is_host(cdns);
> +       //device = cdns3_is_device(cdns);

You may improve use C comment.

> +       host = 1;
> +       device = 0;
> +
> +       if (host)
> +               role = CDNS3_ROLE_HOST;
> +       else if (device)
> +               role = CDNS3_ROLE_GADGET;
> +
> +       if (cdns->desired_dr_mode == cdns->current_dr_mode &&
> +           cdns->role == role)
> +               return;
> +
> +       pm_runtime_get_sync(cdns->dev);
> +       cdns3_role_stop(cdns);
> +
> +       if (host) {
> +               if (cdns->roles[CDNS3_ROLE_HOST])
> +                       cdns3_do_role_switch(cdns, CDNS3_ROLE_HOST);
> +               pm_runtime_put_sync(cdns->dev);
> +               return;
> +       }
> +
> +       if (device)
> +               cdns3_do_role_switch(cdns, CDNS3_ROLE_GADGET);
> +       else
> +               cdns3_do_role_switch(cdns, CDNS3_ROLE_END);
> +
> +       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;
> +
> +       /*
> +        * Request memory region
> +        * region-0: xHCI
> +        * region-1: Peripheral
> +        * region-2: OTG registers
> +        */
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       regs = devm_ioremap_resource(dev, res);
> +
> +       if (IS_ERR(regs))
> +               return PTR_ERR(regs);
> +       cdns->xhci_regs = regs;
> +       cdns->xhci_res = 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);
> +       regs = devm_ioremap_resource(dev, res);
> +       if (IS_ERR(regs))
> +               return PTR_ERR(regs);
> +       cdns->otg_regs = regs;
> +
> +       mutex_init(&cdns->mutex);
> +
> +       cdns->phy = devm_phy_get(dev, "cdns3,usbphy");
> +       if (IS_ERR(cdns->phy)) {
> +               dev_info(dev, "no generic phy found\n");
> +               cdns->phy = NULL;
> +               /*
> +                * fall through here!
> +                * if no generic phy found, phy init
> +                * should be done under boot!
> +                */

If the phy driver is defer-probed, it will be here, it is not an error.
I think you could have a generic phy driver or usb generic phy driver
(drivers/usb/phy/phy-generic.c) even you don't need any operations for
PHY. It will be easy for other platforms.

> +       } else {
> +               phy_init(cdns->phy);
> +       }
> +
> +       ret = cdns3_core_init_role(cdns);
> +       if (ret)
> +               goto err1;
> +
> +       INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
> +       if (ret)
> +               goto err2;
> +
> +       if (ret)
> +               goto err2;
> +
> +       cdns->role = cdns3_get_role(cdns);
> +
> +       ret = devm_request_irq(dev, cdns->irq, cdns3_irq, IRQF_SHARED,
> +                              dev_name(dev), cdns);
> +
> +       if (ret)
> +               goto err2;
> +
> +       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 err2;
> +       }
> +
> +       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:
> +       cdns3_remove_roles(cdns);
> +err1:
> +       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_remove_roles(cdns);
> +
> +       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
> +
> +#ifdef CONFIG_PM
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int cdns3_suspend(struct device *dev)
> +{
> +       //TODO: implements this function
> +       return 0;
> +}
> +
> +static int cdns3_resume(struct device *dev)
> +{
> +       //TODO: implements this function
> +       return 0;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +static int cdns3_runtime_suspend(struct device *dev)
> +{      //TODO: implements this function
> +       return 0;
> +}
> +
> +static int cdns3_runtime_resume(struct device *dev)
> +{
> +       //TODO: implements this function
> +       return 0;
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops cdns3_pm_ops = {
> +       SET_SYSTEM_SLEEP_PM_OPS(cdns3_suspend, cdns3_resume)
> +       SET_RUNTIME_PM_OPS(cdns3_runtime_suspend, cdns3_runtime_resume, NULL)
> +};
> +
> +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),
> +               .pm     = &cdns3_pm_ops,
> +       },
> +};
> +
> +static int __init cdns3_driver_platform_register(void)
> +{
> +       return platform_driver_register(&cdns3_driver);
> +}
> +module_init(cdns3_driver_platform_register);
> +
> +static void __exit cdns3_driver_platform_unregister(void)
> +{
> +       platform_driver_unregister(&cdns3_driver);
> +}
> +module_exit(cdns3_driver_platform_unregister);
> +
> +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..7c8204fe4d3d
> --- /dev/null
> +++ b/drivers/usb/cdns3/core.h
> @@ -0,0 +1,100 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Cadence USBSS DRD Driver.
> + *

Header file

> + * Copyright (C) 2017 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)
> + */
> +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);
> +       irqreturn_t (*irq)(struct cdns3 *cdns);
> +       const char *name;
> +};
> +
> +#define CDNS3_NUM_OF_CLKS      5
> +/**
> + * 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 hardware configuration and cant't be changed.

Based on firmware setting, kernel configuration and hardware configuration.

> + * @current_dr_role: current mode of operation when in dual-role mode
> + * @desired_dr_role: 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_role and current_dr_role
> + *           ----------------------------------------------------------------
> + *           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
> + */
> +struct cdns3 {
> +       struct device                   *dev;
> +       void __iomem                    *xhci_regs;
> +       struct resource                 *xhci_res;
> +       struct cdns3_usb_regs __iomem   *dev_regs;
> +       struct cdns3_otg_regs           *otg_regs;
> +       int irq;
> +       struct cdns3_role_driver        *roles[CDNS3_ROLE_END];
> +       enum cdns3_roles                role;
> +       struct device                   *host_dev;
> +       struct 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;
> +};
> +
> +#endif /* __LINUX_CDNS3_CORE_H */
> --
> 2.17.1
>