RE: [PATCH v4 5/6] usb:cdns3 Add Cadence USB3 DRD Driver

From: Pawel Laszczak
Date: Thu Mar 07 2019 - 00:38:13 EST

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Hi,

>Pawel,
>
>On 14/02/2019 21:45, Pawel Laszczak wrote:
>> This patch introduce new Cadence USBSS DRD driver to linux kernel.
>>
>> The Cadence USBSS DRD Driver is a highly configurable IP Core whichi
>> can be instantiated as Dual-Role Device (DRD), Peripheral Only and
>> Host Only (XHCI)configurations.
>>
>> The current driver has been validated with FPGA burned. We have support
>> for PCIe bus, which is used on FPGA prototyping.
>>
>> The host side of USBSS-DRD controller is compliance with XHCI
>> specification, so it works with standard XHCI linux driver.
>>
>> Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
>> ---
>> drivers/usb/Kconfig | 2 +
>> drivers/usb/Makefile | 2 +
>> drivers/usb/cdns3/Kconfig | 44 +
>> drivers/usb/cdns3/Makefile | 14 +
>> drivers/usb/cdns3/cdns3-pci-wrap.c | 155 +++
>> drivers/usb/cdns3/core.c | 403 ++++++
>> drivers/usb/cdns3/core.h | 116 ++
>> drivers/usb/cdns3/debug.h | 168 +++
>> drivers/usb/cdns3/debugfs.c | 164 +++
>> drivers/usb/cdns3/drd.c | 365 +++++
>> drivers/usb/cdns3/drd.h | 162 +++
>> drivers/usb/cdns3/ep0.c | 907 +++++++++++++
>> drivers/usb/cdns3/gadget-export.h | 28 +
>> drivers/usb/cdns3/gadget.c | 2003 ++++++++++++++++++++++++++++
>> drivers/usb/cdns3/gadget.h | 1207 +++++++++++++++++
>> drivers/usb/cdns3/host-export.h | 28 +
>> drivers/usb/cdns3/host.c | 72 +
>> drivers/usb/cdns3/trace.c | 23 +
>> drivers/usb/cdns3/trace.h | 404 ++++++
>> 19 files changed, 6267 insertions(+)
>> create mode 100644 drivers/usb/cdns3/Kconfig
>> create mode 100644 drivers/usb/cdns3/Makefile
>> create mode 100644 drivers/usb/cdns3/cdns3-pci-wrap.c
>> create mode 100644 drivers/usb/cdns3/core.c
>> create mode 100644 drivers/usb/cdns3/core.h
>> create mode 100644 drivers/usb/cdns3/debug.h
>> create mode 100644 drivers/usb/cdns3/debugfs.c
>> create mode 100644 drivers/usb/cdns3/drd.c
>> create mode 100644 drivers/usb/cdns3/drd.h
>> create mode 100644 drivers/usb/cdns3/ep0.c
>> create mode 100644 drivers/usb/cdns3/gadget-export.h
>> create mode 100644 drivers/usb/cdns3/gadget.c
>> create mode 100644 drivers/usb/cdns3/gadget.h
>> create mode 100644 drivers/usb/cdns3/host-export.h
>> create mode 100644 drivers/usb/cdns3/host.c
>> create mode 100644 drivers/usb/cdns3/trace.c
>> create mode 100644 drivers/usb/cdns3/trace.h
>>
>> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
>> index 987fc5ba6321..5f9334019d04 100644
>> --- a/drivers/usb/Kconfig
>> +++ b/drivers/usb/Kconfig
>> @@ -112,6 +112,8 @@ source "drivers/usb/usbip/Kconfig"
>>
>> endif
>>
>> +source "drivers/usb/cdns3/Kconfig"
>> +
>> source "drivers/usb/mtu3/Kconfig"
>>
>> source "drivers/usb/musb/Kconfig"
>> diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
>> index 7d1b8c82b208..ab125b966cac 100644
>> --- a/drivers/usb/Makefile
>> +++ b/drivers/usb/Makefile
>> @@ -12,6 +12,8 @@ obj-$(CONFIG_USB_DWC3) += dwc3/
>> obj-$(CONFIG_USB_DWC2) += dwc2/
>> obj-$(CONFIG_USB_ISP1760) += isp1760/
>>
>> +obj-$(CONFIG_USB_CDNS3) += cdns3/
>> +
>> obj-$(CONFIG_USB_MON) += mon/
>> obj-$(CONFIG_USB_MTU3) += mtu3/
>>
>> diff --git a/drivers/usb/cdns3/Kconfig b/drivers/usb/cdns3/Kconfig
>> new file mode 100644
>> index 000000000000..27cb3d8dbe3d
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/Kconfig
>> @@ -0,0 +1,44 @@
>> +config USB_CDNS3
>> + tristate "Cadence USB3 Dual-Role Controller"
>> + depends on USB_SUPPORT && (USB || USB_GADGET) && HAS_DMA
>> + help
>> + Say Y here if your system has a cadence USB3 dual-role controller.
>> + It supports: dual-role switch, Host-only, and Peripheral-only.
>> +
>> + If you choose to build this driver is a dynamically linked
>> + as module, the module will be called cdns3.ko.
>> +
>> +if USB_CDNS3
>> +
>> +config USB_CDNS3_GADGET
>> + bool "Cadence USB3 device controller"
>> + depends on USB_GADGET
>> + help
>> + Say Y here to enable device controller functionality of the
>> + cadence USBSS-DEV driver.
>
>"Cadence" ?
>
>> +
>> + This controller supports FF, HS and SS mode. It doesn't support
>> + LS and SSP mode.
>> +
>> +config USB_CDNS3_HOST
>> + bool "Cadence USB3 host controller"
>> + depends on USB_XHCI_HCD
>> + help
>> + Say Y here to enable host controller functionality of the
>> + cadence driver.
>> +
>> + Host controller is compliant with XHCI so it will use
>> + standard XHCI driver.
>> +
>> +config USB_CDNS3_PCI_WRAP
>> + tristate "Cadence USB3 support on PCIe-based platforms"
>> + depends on USB_PCI && ACPI
>> + default USB_CDNS3
>> + help
>> + If you're using the USBSS Core IP with a PCIe, please say
>> + 'Y' or 'M' here.
>> +
>> + If you choose to build this driver as module it will
>> + be dynamically linked and module will be called cdns3-pci.ko
>> +
>> +endif
>> diff --git a/drivers/usb/cdns3/Makefile b/drivers/usb/cdns3/Makefile
>> new file mode 100644
>> index 000000000000..8f9438593375
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/Makefile
>> @@ -0,0 +1,14 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +# define_trace.h needs to know how to find our header
>> +CFLAGS_trace.o := -I$(src)
>> +
>> +cdns3-y := core.o drd.o trace.o
>> +
>> +obj-$(CONFIG_USB_CDNS3) += cdns3.o
>> +ifneq ($(CONFIG_DEBUG_FS),)
>> + cdns3-y += debugfs.o
>> +endif
>> +
>> +cdns3-$(CONFIG_USB_CDNS3_GADGET) += gadget.o ep0.o
>> +cdns3-$(CONFIG_USB_CDNS3_HOST) += host.o
>> +obj-$(CONFIG_USB_CDNS3_PCI_WRAP) += cdns3-pci-wrap.o
>> diff --git a/drivers/usb/cdns3/cdns3-pci-wrap.c b/drivers/usb/cdns3/cdns3-pci-wrap.c
>> new file mode 100644
>> index 000000000000..d0b2d3d9b983
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/cdns3-pci-wrap.c
>> @@ -0,0 +1,155 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS PCI Glue driver
>> + *
>> + * Copyright (C) 2018 Cadence.
>
>2018-2019?
>
>> + *
>> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/pci.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/slab.h>
>> +
>> +struct cdns3_wrap {
>> + struct platform_device *plat_dev;
>> + struct pci_dev *hg_dev;
>> + struct resource dev_res[4];
>> +};
>> +
>> +struct cdns3_wrap wrap;
>> +
>> +#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 = "dev";
>> + res[RES_DEV_ID].flags = IORESOURCE_MEM;
>> + dev_dbg(&pdev->dev, "USBSS-DEV physical base addr: %pa\n",
>> + &res[RES_DEV_ID].start);
>> +
>> + res[RES_HOST_ID].start = pci_resource_start(pdev, PCI_BAR_HOST);
>> + res[RES_HOST_ID].end = pci_resource_end(pdev, PCI_BAR_HOST);
>> + res[RES_HOST_ID].name = "xhci";
>> + res[RES_HOST_ID].flags = IORESOURCE_MEM;
>> + dev_dbg(&pdev->dev, "USBSS-XHCI physical base addr: %pa\n",
>> + &res[RES_HOST_ID].start);
>> +
>> + res[RES_DRD_ID].start = pci_resource_start(pdev, PCI_BAR_OTG);
>> + res[RES_DRD_ID].end = pci_resource_end(pdev, PCI_BAR_OTG);
>> + res[RES_DRD_ID].name = "otg";
>> + res[RES_DRD_ID].flags = IORESOURCE_MEM;
>> + dev_dbg(&pdev->dev, "USBSS-DRD physical base addr: %pa\n",
>> + &res[RES_DRD_ID].start);
>> +
>> + /* Interrupt common for both device and XHCI */
>> + wrap->dev_res[RES_IRQ_ID].start = pdev->irq;
>> + wrap->dev_res[RES_IRQ_ID].name = "cdns3-irq";
>> + wrap->dev_res[RES_IRQ_ID].flags = IORESOURCE_IRQ;
>> +
>> + /* set up platform device info */
>> + memset(&plat_info, 0, sizeof(plat_info));
>> + plat_info.parent = &pdev->dev;
>> + plat_info.fwnode = pdev->dev.fwnode;
>> + plat_info.name = PLAT_DRIVER_NAME;
>> + plat_info.id = pdev->devfn;
>> + plat_info.res = wrap->dev_res;
>> + plat_info.num_res = ARRAY_SIZE(wrap->dev_res);
>> + plat_info.dma_mask = pdev->dma_mask;
>> +
>> + /* register platform device */
>> + wrap->plat_dev = platform_device_register_full(&plat_info);
>> + if (IS_ERR(wrap->plat_dev))
>> + return PTR_ERR(wrap->plat_dev);
>> +
>> + pci_set_drvdata(pdev, wrap);
>> +
>> + return err;
>> +}
>> +
>> +void cdns3_pci_remove(struct pci_dev *pdev)
>> +{
>> + struct cdns3_wrap *wrap = (struct cdns3_wrap *)pci_get_drvdata(pdev);
>> +
>> + platform_device_unregister(wrap->plat_dev);
>> +}
>> +
>> +static const struct pci_device_id cdns3_pci_ids[] = {
>> + { PCI_DEVICE(CDNS_VENDOR_ID, CDNS_DEVICE_ID), },
>> + { 0, }
>> +};
>> +
>> +static struct pci_driver cdns3_pci_driver = {
>> + .name = PCI_DRIVER_NAME,
>> + .id_table = cdns3_pci_ids,
>> + .probe = cdns3_pci_probe,
>> + .remove = cdns3_pci_remove,
>> +};
>> +
>> +module_pci_driver(cdns3_pci_driver);
>> +MODULE_DEVICE_TABLE(pci, cdns3_pci_ids);
>> +
>> +MODULE_AUTHOR("Pawel Laszczak <pawell@xxxxxxxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("Cadence USBSS PCI wrapperr");
>> +
>> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
>> new file mode 100644
>> index 000000000000..aa2f63241dab
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/core.c
>> @@ -0,0 +1,403 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS DRD Driver.
>> + *
>> + * Copyright (C) 2018 Cadence.
>> + * Copyright (C) 2017-2018 NXP
>> + *
>> + * Author: Peter Chen <peter.chen@xxxxxxx>
>> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/pm_runtime.h>
>> +
>> +#include "gadget.h"
>> +#include "core.h"
>> +#include "host-export.h"
>> +#include "gadget-export.h"
>> +#include "drd.h"
>> +#include "debug.h"
>> +
>> +static inline
>> +struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
>> +{
>> + WARN_ON(cdns->role >= CDNS3_ROLE_END || !cdns->roles[cdns->role]);
>> + return cdns->roles[cdns->role];
>> +}
>> +
>> +static int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
>> +{
>> + int ret;
>> +
>> + if (WARN_ON(role >= CDNS3_ROLE_END))
>> + return 0;
>> +
>> + if (!cdns->roles[role])
>> + return -ENXIO;
>> +
>> + if (cdns->roles[role]->state == CDNS3_ROLE_STATE_ACTIVE)
>> + return 0;
>> +
>> + mutex_lock(&cdns->mutex);
>> + cdns->role = role;
>> + ret = cdns->roles[role]->start(cdns);
>> + if (!ret)
>> + cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
>> + mutex_unlock(&cdns->mutex);
>> + return ret;
>> +}
>> +
>> +void cdns3_role_stop(struct cdns3 *cdns)
>> +{
>> + enum cdns3_roles role = cdns->role;
>> +
>> + if (role >= CDNS3_ROLE_END) {
>> + WARN_ON(role > CDNS3_ROLE_END);
>> + return;
>> + }
>> +
>> + if (cdns->roles[role]->state == CDNS3_ROLE_STATE_INACTIVE)
>> + return;
>> +
>> + mutex_lock(&cdns->mutex);
>> + cdns->roles[role]->stop(cdns);
>> + cdns->roles[role]->state = CDNS3_ROLE_STATE_INACTIVE;
>> + mutex_unlock(&cdns->mutex);
>> +}
>> +
>> +/*
>> + * cdns->role gets from cdns3_get_initial_role, and this API tells role at the
>> + * runtime.
>> + * If both roles are supported, the role is selected based on vbus/id.
>> + * It could be read from OTG register or external connector.
>> + * If only single role is supported, only one role structure
>> + * is allocated, cdns->roles[CDNS3_ROLE_HOST] or cdns->roles[CDNS3_ROLE_GADGET].
>> + */
>> +static enum cdns3_roles cdns3_get_initial_role(struct cdns3 *cdns)
>> +{
>> + if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) {
>> + if (cdns3_is_host(cdns))
>> + return CDNS3_ROLE_HOST;
>> + if (cdns3_is_device(cdns))
>> + return CDNS3_ROLE_GADGET;
>> + }
>> + return cdns->roles[CDNS3_ROLE_HOST]
>> + ? CDNS3_ROLE_HOST
>> + : CDNS3_ROLE_GADGET;
>> +}
>> +
>> +static void cdns3_exit_roles(struct cdns3 *cdns)
>> +{
>> + cdns3_role_stop(cdns);
>> + cdns3_drd_exit(cdns);
>> +}
>> +
>> +/**
>> + * cdns3_core_init_role - initialize role of operation
>> + * @cdns: Pointer to cdns3 structure
>> + *
>> + * Returns 0 on success otherwise negative errno
>> + */
>> +static int cdns3_core_init_role(struct cdns3 *cdns)
>> +{
>> + struct device *dev = cdns->dev;
>> + enum usb_dr_mode best_dr_mode;
>> + enum usb_dr_mode dr_mode;
>> + int ret = 0;
>> +
>> + dr_mode = usb_get_dr_mode(dev);
>> + cdns->role = CDNS3_ROLE_END;
>> +
>> + /*
>> + * If driver can't read mode by means of usb_get_dr_mdoe function then
>
>s/mdoe/mode
>
>> + * 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;
>
>Might be worth mentioning that cdns->dr_mode is strap configuration
>at this point.
I added such information. It could help in understanding code.
>
>What exactly are we trying to do here?
>My guess is that choosen dr_mode can be equal to or subset of strap configuration?
>
We have three possibility regarding dr_mode:
1. It can be read from strap bits
2. we have kernel configuration
3. we can read it from dts.

I assume that driver should select dr_mode considering these three settings.

>Does this work?

>
> if (cdns->dr_mode != USB_DR_MODE_OTG) {
> if (cdns->dr_mode != dr_mode) {
> dev_err(dev, "Incorrect dr_mode configuration: strap %d: requested %d\n",
> cdns->dr_mode, dr_mode);
> }
> }
>
>At this point, dr_mode contains the mode we need to use.

I don't understand. Do you want to replace below block with above condition ?
If yes, what with case cdns->dr_mode = USB_DR_MODE_OTG (strap configuration)
and dr_mode = USB_DR_MODE_HOST (Kernel configuration).
I think that in this case driver should limit cdns->dr_mode to USB_DR_MODE_HOST
because gadget driver is disabled.
Of course we can also consider such case as incorrect kernel configuration.

>
>> +
>> + 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
>
>"desired_dr_mode might have changed so we need to update the controller configuration"?

Sounds better.

>
>> + * configuration
>> + */
>> + ret = cdns3_drd_update_mode(cdns);
>> + if (ret)
>> + goto err;
>> +
>> + cdns->role = cdns3_get_initial_role(cdns);
>> +
>> + ret = cdns3_role_start(cdns, cdns->role);
>> + if (ret) {
>> + dev_err(dev, "can't start %s role\n",
>> + cdns3_get_current_role_driver(cdns)->name);
>> + goto err;
>> + }
>> +
>> + return ret;
>> +err:
>> + cdns3_exit_roles(cdns);
>> + return ret;
>> +}
>> +
>> +/**
>> + * cdsn3_get_real_role - get real role of controller based on hardware settings.
>> + * @cdns: Pointer to cdns3 structure
>> + *
>> + * Returns role
>> + */
>> +enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns)
>> +{
>> + enum cdns3_roles role = CDNS3_ROLE_END;
>> +
>> + if (cdns->current_dr_mode == USB_DR_MODE_OTG) {
>> + if (cdns3_get_id(cdns))
>> + role = CDNS3_ROLE_GADGET;
>> + else
>> + role = CDNS3_ROLE_HOST;
>> + } else {
>> + if (cdns3_is_host(cdns))
>> + role = CDNS3_ROLE_HOST;
>> + if (cdns3_is_device(cdns))
>> + role = CDNS3_ROLE_GADGET;
>> + }
>> +
>> + return role;
>> +}
>> +
>> +/**
>> + * cdns3_role_switch - work queue handler for role switch
>> + *
>> + * @work: work queue item structure
>> + *
>> + * Handles below events:
>> + * - Role switch for dual-role devices
>> + * - CDNS3_ROLE_GADGET <--> CDNS3_ROLE_END for peripheral-only devices
>> + */
>> +static void cdns3_role_switch(struct work_struct *work)
>> +{
>> + enum cdns3_roles role = CDNS3_ROLE_END;
>> + struct cdns3_role_driver *role_drv;
>> + enum cdns3_roles current_role;
>> + struct cdns3 *cdns;
>> + int ret = 0;
>> +
>> + cdns = container_of(work, struct cdns3, role_switch_wq);
>> +
>> + /* During switching cdns->role can be different then role */
>s/then/than
>
>The comment is a bit misleading. The purpose of this switch function
>is to do a switch if the role needs to be changed.
>
>> + role = cdsn3_get_real_role(cdns);
>> +
>> + role_drv = cdns3_get_current_role_driver(cdns);
>> +
>> + pm_runtime_get_sync(cdns->dev);
>
>pm_runtime_get_sync() must be moved to before cdsn3_get_real_role() as that function
>accesses a device register.

Ok.
>
>> +
>> + /* Disable current role. This state can be forced from user space. */
>/* Disable current role if requrested 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);
>
>You already did cdns3_get_real_role before. This is redundant.
I'm not sure. I remember that it has been added for some reason, but I can't remember this case.
I need to check this.

>> +
>> + current_role = cdns->role;
>> + dev_dbg(cdns->dev, "Switching role");
>> +
>> + ret = cdns3_role_start(cdns, role);
>> + if (ret) {
>> + /* Back to current role */
>> + dev_err(cdns->dev, "set %d has failed, back to %d\n",
>> + role, current_role);
>> + cdns3_role_start(cdns, current_role);
>
>Need to check return value here as well? And complain loud if that fails too.
>
Ok.

>> + }
>> +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_byname(pdev, IORESOURCE_MEM, "xhci");
>> + if (!res)
>> + return -ENXIO;
>> +
>> + cdns->xhci_res[1] = *res;
>> +
>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
>> + regs = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(regs))
>> + return PTR_ERR(regs);
>> + cdns->dev_regs = regs;
>> +
>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
>> + if (!res)
>> + return -ENXIO;
>> +
>> + cdns->otg_res = *res;
>> +
>> + mutex_init(&cdns->mutex);
>> +
>> + cdns->phy = devm_phy_optional_get(dev, "cdns3,usbphy");
>> + if (IS_ERR(cdns->phy))
>> + return PTR_ERR(cdns->phy);
>> +
>> + phy_init(cdns->phy);
>> +
>> + INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
>> +
>> + ret = cdns3_drd_init(cdns);
>> + if (ret)
>> + goto err;
>> +
>> + ret = cdns3_core_init_role(cdns);
>> + if (ret)
>> + goto err;
>> +
>> + cdns3_debugfs_init(cdns);
>> + device_set_wakeup_capable(dev, true);
>> + pm_runtime_set_active(dev);
>> + pm_runtime_enable(dev);
>> +
>> + /*
>> + * The controller needs less time between bus and controller suspend,
>> + * and we also needs a small delay to avoid frequently entering low
>> + * power mode.
>> + */
>> + pm_runtime_set_autosuspend_delay(dev, 20);
>> + pm_runtime_mark_last_busy(dev);
>> + pm_runtime_use_autosuspend(dev);
>> + dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
>> +
>> + return 0;
>> +
>> +err:
>> + phy_exit(cdns->phy);
>> + return ret;
>> +}
>> +
>> +/**
>> + * cdns3_remove - unbind drd driver and clean up
>> + * @pdev: Pointer to Linux platform device
>> + *
>> + * Returns 0 on success otherwise negative errno
>> + */
>> +static int cdns3_remove(struct platform_device *pdev)
>> +{
>> + struct cdns3 *cdns = platform_get_drvdata(pdev);
>> +
>> + pm_runtime_get_sync(&pdev->dev);
>> + pm_runtime_disable(&pdev->dev);
>> + pm_runtime_put_noidle(&pdev->dev);
>
>I'm not sure if this is handled right.
>You are still accessing the device in below cnds3_*() calls.
>
>> + cdns3_debugfs_exit(cdns);
>> + cdns3_exit_roles(cdns);> + phy_exit(cdns->phy);
>
>Is the device is in runtime suspended state at this point?
>
>> + return 0;
>> +}
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id of_cdns3_match[] = {
>> + { .compatible = "cdns,usb3-1.0.0" },
>> + { .compatible = "cdns,usb3-1.0.1" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, of_cdns3_match);
>> +#endif
>> +
>> +static struct platform_driver cdns3_driver = {
>> + .probe = cdns3_probe,
>> + .remove = cdns3_remove,
>> + .driver = {
>> + .name = "cdns-usb3",
>> + .of_match_table = of_match_ptr(of_cdns3_match),
>> + },
>> +};
>> +
>> +module_platform_driver(cdns3_driver);
>> +
>> +MODULE_ALIAS("platform:cdns3");
>> +MODULE_AUTHOR("Pawel Laszczak <pawell@xxxxxxxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");
>> diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
>> new file mode 100644
>> index 000000000000..fb4b39206158
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/core.h
>> @@ -0,0 +1,116 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Cadence USBSS DRD Header File.
>> + *
>> + * Copyright (C) 2017-2018 NXP
>> + * Copyright (C) 2018 Cadence.
>> + *
>> + * Authors: Peter Chen <peter.chen@xxxxxxx>
>> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + */
>> +#include <linux/usb/otg.h>
>> +
>> +#ifndef __LINUX_CDNS3_CORE_H
>> +#define __LINUX_CDNS3_CORE_H
>> +
>> +struct cdns3;
>> +enum cdns3_roles {
>> + CDNS3_ROLE_HOST = 0,
>> + CDNS3_ROLE_GADGET,
>> + CDNS3_ROLE_END,
>> +};
>> +
>> +/**
>> + * struct cdns3_role_driver - host/gadget role driver
>> + * @start: start this role
>> + * @stop: stop this role
>> + * @suspend: suspend callback for this role
>> + * @resume: resume callback for this role
>> + * @irq: irq handler for this role
>> + * @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
>
>Last 3 lines should be reduced to
>
> USB_DR_MODE_OTG | USB_DR_MODE_OTG, USB_DR_MODE_HOST or
> | USB_DR_MODE_PERIPHERAL
>

Ok.

>> + *
>> + * 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..1929edb3a521
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debug.h
>> @@ -0,0 +1,168 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Cadence USBSS DRD Driver.
>> + * Debug header file.
>> + *
>> + * Copyright (C) 2018 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + */
>> +#ifndef __LINUX_CDNS3_DEBUG
>> +#define __LINUX_CDNS3_DEBUG
>> +
>> +#include "core.h"
>> +
>> +static inline char *cdns3_decode_usb_irq(char *str,
>> + enum usb_device_speed speed,
>> + u32 usb_ists)
>> +{
>> + int ret;
>> +
>> + ret = sprintf(str, "IRQ %08x = ", usb_ists);
>> +
>> + if (usb_ists & (USB_ISTS_CON2I | USB_ISTS_CONI)) {
>> + ret += sprintf(str + ret, "Connection %s\n",
>> + usb_speed_string(speed));
>> + }
>> + if (usb_ists & USB_ISTS_CON2I || usb_ists & USB_ISTS_CONI)
>> + ret += sprintf(str + ret, "Disconnection ");
>> + if (usb_ists & USB_ISTS_L2ENTI)
>> + ret += sprintf(str + ret, "suspended ");
>> +
>> + if (usb_ists & USB_ISTS_L2EXTI)
>> + ret += sprintf(str + ret, "L2 exit ");
>> + if (usb_ists & USB_ISTS_U3EXTI)
>> + ret += sprintf(str + ret, "U3 exit ");
>> + if (usb_ists & USB_ISTS_UWRESI)
>> + ret += sprintf(str + ret, "Warm Reset ");
>> + if (usb_ists & USB_ISTS_UHRESI)
>> + ret += sprintf(str + ret, "Hot Reset ");
>> + if (usb_ists & USB_ISTS_U2RESI)
>> + ret += sprintf(str + ret, "Reset");
>> +
>> + return str;
>> +}
>> +
>> +static inline char *cdns3_decode_ep_irq(char *str,
>> + u32 ep_sts,
>> + const char *ep_name)
>> +{
>> + int ret;
>> +
>> + ret = sprintf(str, "IRQ for %s: %08x ", ep_name, ep_sts);
>> +
>> + if (ep_sts & EP_STS_SETUP)
>> + ret += sprintf(str + ret, "SETUP ");
>> + if (ep_sts & EP_STS_IOC)
>> + ret += sprintf(str + ret, "IOC ");
>> + if (ep_sts & EP_STS_ISP)
>> + ret += sprintf(str + ret, "ISP ");
>> + if (ep_sts & EP_STS_DESCMIS)
>> + ret += sprintf(str + ret, "DESCMIS ");
>> + if (ep_sts & EP_STS_STREAMR)
>> + ret += sprintf(str + ret, "STREAMR ");
>> + if (ep_sts & EP_STS_MD_EXIT)
>> + ret += sprintf(str + ret, "MD_EXIT ");
>> + if (ep_sts & EP_STS_TRBERR)
>> + ret += sprintf(str + ret, "TRBERR ");
>> + if (ep_sts & EP_STS_NRDY)
>> + ret += sprintf(str + ret, "NRDY ");
>> + if (ep_sts & EP_STS_PRIME)
>> + ret += sprintf(str + ret, "PRIME ");
>> + if (ep_sts & EP_STS_SIDERR)
>> + ret += sprintf(str + ret, "SIDERRT ");
>> + if (ep_sts & EP_STS_OUTSMM)
>> + ret += sprintf(str + ret, "OUTSMM ");
>> + if (ep_sts & EP_STS_ISOERR)
>> + ret += sprintf(str + ret, "ISOERR ");
>> + if (ep_sts & EP_STS_IOT)
>> + ret += sprintf(str + ret, "IOT ");
>> +
>> + return str;
>> +}
>> +
>> +static inline char *cdns3_decode_epx_irq(char *str,
>> + char *ep_name,
>> + u32 ep_sts)
>> +{
>> + return cdns3_decode_ep_irq(str, ep_sts, ep_name);
>> +}
>> +
>> +static inline char *cdns3_decode_ep0_irq(char *str,
>> + int dir,
>> + u32 ep_sts)
>> +{
>> + return cdns3_decode_ep_irq(str, ep_sts,
>> + dir ? "ep0IN" : "ep0OUT");
>> +}
>> +
>> +/**
>> + * Debug a transfer ring.
>> + *
>> + * Prints out all TRBs in the endpoint ring, even those after the Link TRB.
>> + *.
>> + */
>> +static inline char *cdns3_dbg_ring(struct cdns3_endpoint *priv_ep,
>> + struct cdns3_trb *ring, char *str)
>> +{
>> + dma_addr_t addr = priv_ep->trb_pool_dma;
>> + struct cdns3_trb *trb;
>> + int trb_per_sector;
>> + int ret = 0;
>> + int i;
>> +
>> + trb_per_sector = GET_TRBS_PER_SEGMENT(priv_ep->type);
>> +
>> + trb = &priv_ep->trb_pool[priv_ep->dequeue];
>> + ret += sprintf(str + ret, "\n\t\tRing contents for %s:", priv_ep->name);
>> +
>> + ret += sprintf(str + ret,
>> + "\n\t\tRing deq index: %d, trb: %p (virt), 0x%llx (dma)\n",
>> + priv_ep->dequeue, trb,
>> + (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
>> +
>> + trb = &priv_ep->trb_pool[priv_ep->enqueue];
>> + ret += sprintf(str + ret,
>> + "\t\tRing enq index: %d, trb: %p (virt), 0x%llx (dma)\n",
>> + priv_ep->enqueue, trb,
>> + (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
>> +
>> + ret += sprintf(str + ret,
>> + "\t\tfree trbs: %d, CCS=%d, PCS=%d\n",
>> + priv_ep->free_trbs, priv_ep->ccs, priv_ep->pcs);
>> +
>> + if (trb_per_sector > TRBS_PER_SEGMENT)
>> + trb_per_sector = TRBS_PER_SEGMENT;
>> +
>> + if (trb_per_sector > TRBS_PER_SEGMENT) {
>> + sprintf(str + ret, "\t\tTo big transfer ring %d\n",
>> + trb_per_sector);
>> + return str;
>> + }
>> +
>> + for (i = 0; i < trb_per_sector; ++i) {
>> + trb = &ring[i];
>> + ret += sprintf(str + ret,
>> + "\t\t@%pad %08x %08x %08x\n", &addr,
>> + le32_to_cpu(trb->buffer),
>> + le32_to_cpu(trb->length),
>> + le32_to_cpu(trb->control));
>> + addr += sizeof(*trb);
>> + }
>> +
>> + return str;
>> +}
>> +
>> +void cdns3_dbg(struct cdns3_device *priv_dev, const char *fmt, ...);
>> +
>> +#ifdef CONFIG_DEBUG_FS
>> +void cdns3_debugfs_init(struct cdns3 *cdns);
>> +void cdns3_debugfs_exit(struct cdns3 *cdns);
>> +#else
>> +void cdns3_debugfs_init(struct cdns3 *cdns);
>> +{ }
>> +void cdns3_debugfs_exit(struct cdns3 *cdns);
>> +{ }
>> +#endif
>> +
>> +#endif /*__LINUX_CDNS3_DEBUG*/
>> diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
>> new file mode 100644
>> index 000000000000..d8fcd90d05b3
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/debugfs.c
>> @@ -0,0 +1,164 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS DRD Controller DebugFS filer.
>> + *
>> + * Copyright (C) 2018 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/types.h>
>> +#include <linux/debugfs.h>
>> +#include <linux/seq_file.h>
>> +#include <linux/uaccess.h>
>> +
>> +#include "core.h"
>> +#include "gadget.h"
>> +#include "drd.h"
>> +
>> +static int cdns3_mode_show(struct seq_file *s, void *unused)
>> +{
>> + struct cdns3 *cdns = s->private;
>> +
>> + switch (cdns->current_dr_mode) {
>> + case USB_DR_MODE_HOST:
>> + seq_puts(s, "host\n");
>> + break;
>> + case USB_DR_MODE_PERIPHERAL:
>> + seq_puts(s, "device\n");
>> + break;
>> + case USB_DR_MODE_OTG:
>> + seq_puts(s, "otg\n");
>> + break;
>> + default:
>> + seq_puts(s, "UNKNOWN mode\n");
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int cdns3_mode_open(struct inode *inode, struct file *file)
>> +{
>> + return single_open(file, cdns3_mode_show, inode->i_private);
>> +}
>> +
>> +static ssize_t cdns3_mode_write(struct file *file,
>> + const char __user *ubuf,
>> + size_t count, loff_t *ppos)
>> +{
>> + struct seq_file *s = file->private_data;
>> + struct cdns3 *cdns = s->private;
>> + u32 mode = USB_DR_MODE_UNKNOWN;
>> + char buf[32];
>> +
>> + if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
>> + return -EFAULT;
>> +
>> + if (!strncmp(buf, "host", 4)) {
>> + if (cdns->dr_mode == USB_DR_MODE_HOST ||
>> + cdns->dr_mode == USB_DR_MODE_OTG) {
>> + mode = USB_DR_MODE_HOST;
>> + }
>> + }
>> +
>> + if (!strncmp(buf, "device", 6))
>> + if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL ||
>> + cdns->dr_mode == USB_DR_MODE_OTG)
>> + mode = USB_DR_MODE_PERIPHERAL;
>> +
>> + if (!strncmp(buf, "otg", 3) && cdns->dr_mode == USB_DR_MODE_OTG)
>> + mode = USB_DR_MODE_OTG;
>> +
>> + if (mode == USB_DR_MODE_UNKNOWN) {
>> + dev_err(cdns->dev, "Failed: incorrect mode setting\n");
>> + return -EFAULT;
>> + }
>> +
>> + if (cdns->current_dr_mode != mode) {
>> + cdns->desired_dr_mode = mode;
>> + cdns->debug_disable = 0;
>Instead of forcing debug_disable here maybe you hould check if it is set
>and complain that mode can't be changed when debug_disable is set?

Ok, I will change this.
>
>> + cdns3_role_stop(cdns);
>> + cdns3_drd_update_mode(cdns);
>
>Need to check return value.

Ok,

>
>> + 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);
>
>What is the purpose of this disable debugfs file?
>To stop the currently active role?

Generally it was added for testing purpose. Yes it's disable the current active role.
I used it for testing loading/unloading driver.
Also sometime I used it to take log from trace when I'm working remotely.

>
>> + }
>> +
>> + return count;
>> +}
>> +
>> +static int cdns3_disable_open(struct inode *inode, struct file *file)
>> +{
>> + return single_open(file, cdns3_disable_show, inode->i_private);
>> +}
>> +
>> +static const struct file_operations cdns3_disable_fops = {
>> + .open = cdns3_disable_open,
>> + .write = cdns3_disable_write,
>> + .read = seq_read,
>> + .llseek = seq_lseek,
>> + .release = single_release,
>> +};
>> +
>> +void cdns3_debugfs_init(struct cdns3 *cdns)
>> +{
>> + struct dentry *root;
>> +
>> + root = debugfs_create_dir(dev_name(cdns->dev), NULL);
>> + cdns->root = root;
>> + if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET) &&
>> + IS_ENABLED(CONFIG_USB_CDNS3_HOST))
>> + debugfs_create_file("mode", 0644, root, cdns,
>> + &cdns3_mode_fops);
>> +
>> + debugfs_create_file("disable", 0644, root, cdns,
>> + &cdns3_disable_fops);
>> +}
>> +
>> +void cdns3_debugfs_exit(struct cdns3 *cdns)
>> +{
>> + debugfs_remove_recursive(cdns->root);
>> +}
>> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
>> new file mode 100644
>> index 000000000000..3e56338cd7b9
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/drd.c
>> @@ -0,0 +1,365 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS DRD Driver.
>> + *
>> + * Copyright (C) 2018 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx
>> + *
>> + */
>> +#include <linux/kernel.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/delay.h>
>> +#include <linux/usb/otg.h>
>> +
>> +#include "gadget.h"
>> +#include "drd.h"
>> +#include "core.h"
>> +
>> +static int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on);
>> +static int cdns3_drd_switch_host(struct cdns3 *cdns, int on);
>> +
>> +/**
>> + * cdns3_set_mode - change mode of OTG Core
>> + * @cdns: pointer to context structure
>> + * @mode: selected mode from cdns_role
>> + *
>> + * Returns 0 on success otherwise negative errno
>> + */
>> +int cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
>> +{
>> + int ret = 0;
>> + u32 reg;
>> +
>> + cdns->current_dr_mode = mode;
>> +
>> + switch (mode) {
>> + case USB_DR_MODE_PERIPHERAL:
>> + dev_info(cdns->dev, "Set controller to Gadget mode\n");
>
>dev_dbg()?
>
>> + ret = cdns3_drd_switch_gadget(cdns, 1);
>> + break;
>> + case USB_DR_MODE_HOST:
>> + dev_info(cdns->dev, "Set controller to Host mode\n");
>
>dev_dbg()
>
>> + ret = cdns3_drd_switch_host(cdns, 1);
>> + break;
>> + case USB_DR_MODE_OTG:
>> + dev_info(cdns->dev, "Set controller to OTG mode\n");
>
>dev_dbg()
>
>> + 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);
>> + }
>> +
>
>Don't you have to clear IDPULLUP when you switch to PERIPHERAL or HOST mode?
No I don't have to.
Int this place OVERRIDE_IDPULLUP - from spec: "ID Pin Sample Enable: Active High. Signal that enables the sampling of the analog ID line."

>
>> + /*
>> + * Hardware specification says: "ID_VALUE must be valid within
>> + * 50ms after idpullup is set to '1" so driver must wait
>> + * 50ms before reading this pin.
>> + */
>> + usleep_range(50000, 60000);
>> + break;
>> + default:
>> + cdns->current_dr_mode = USB_DR_MODE_UNKNOWN;
>> + dev_err(cdns->dev, "Unsupported mode of operation %d\n", mode);
>> + return -EINVAL;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +int cdns3_get_id(struct cdns3 *cdns)
>> +{
>> + int id;
>> +
>> + id = readl(&cdns->otg_regs->sts) & OTGSTS_ID_VALUE;
>> + dev_dbg(cdns->dev, "OTG ID: %d", id);
>> + return id;
>> +}
>> +
>> +int cdns3_is_host(struct cdns3 *cdns)
>> +{
>> + if (cdns->current_dr_mode == USB_DR_MODE_HOST)
>> + return 1;
>
>don't you have to return 0 if current_dr_mode == USB_DR_MODE_PERIPHERAL?

"return 0" is few lines below.

>
>> + 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;
>
>don't you have to return 0 if current_dr_mode == USB_DR_MODE_HOST?

"return 0" is few lines below.
>
>> + 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
>> + */
>> +static 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 for Host mode is turned on\n");
>s/for/till
>
>> + ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_XHCI_READY,
>> + OTGSTS_XHCI_READY, 100000);
>> +
>> + if (ret)
>> + return ret;
>> + } else {
>> + usleep_range(30, 40);
>> + writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP |
>> + OTGCMD_DEV_POWER_OFF | OTGCMD_HOST_POWER_OFF,
>> + &cdns->otg_regs->cmd);
>> + usleep_range(3000, 4000);
>
>why do you need delays before and after the write?
I think that the first it is not necessary. I'm going to remove it.
The second I'm going to replace with
cdns3_handshake(&cdns->otg_regs->state,
OTGSTATE_HOST_STATE_MASK,
0, 2000000);
It should ensure as short as possible delay to allow DRD transit to H_IDLE state.

>> + }
>> +
>> + 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
>> + */
>> +static 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 for Device mode is turned on\n");
>
>s/for/till
>
>> +
>> + ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_DEV_READY,
>> + OTGSTS_DEV_READY, 100000);
>> +
>> + if (ret)
>> + 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);
>> + usleep_range(3000, 4000);
>
>why do you need a delay after the write?
It's time required for proper transition to DEV_IDLE state.
>
>> + }
>> +
>> + 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;
>> +
>> + if (cdns3_is_host(cdns))
>> + ret = cdns3_drd_switch_host(cdns, 1);
>> + else
>> + ret = cdns3_drd_switch_gadget(cdns, 1);
>> +
>> + if (ret)
>> + return ret;
>> +
>> + cdns3_otg_enable_irq(cdns);
>
>Schedule switch workqueue to deal with updated ID state?

Schedule is added in cdns3_drd_irq.
Driver should receive interrupt.

>
>> + 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;
>> +
>> + cdns3_drd_switch_gadget(cdns, 0);
>> + cdns3_drd_switch_host(cdns, 0);
>
>Why are you stopping gadget/host here?
>One or both of might not have been started.

These functions operate only on OTG registers. It's according with
CDNS3 DRD specification.
They don't stop gadget/host, but only set:
HOST_BUS_DROP=1
HOST_POWER_OF=1
DEV_BUS_DROP=1
DEV_POWER_OFF=1

Driver must set these bits before reconfiguring DRD.
>
>> +
>> + 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));
>> +
>> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
>> +
>> + 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;
>> +}
>> +
>> +int cdns3_drd_exit(struct cdns3 *cdns)
>> +{
>> + return cdns3_drd_switch_host(cdns, 0);
>
>Why only stopping host?
cdns3_drd_switch_gadget(cdns, 0) make the same as cdns3_drd_switch_host(cdns, 0).
It's only set some bits in OTG_CMD register, to force transition to IDLE state.
>
>I think we need to stop active role, disable IRQ generation and free irq?
Stop active role is invoked in core.c file from cdns3_remove ->cdns3_exit_roles

>
>> +}
>
><snip>
>
>> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
>> new file mode 100644
>> index 000000000000..7f7f24ee3c4b
>> --- /dev/null
>> +++ b/drivers/usb/cdns3/gadget.c
>> @@ -0,0 +1,2003 @@
>> +// 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@xxxxxxxxxxx>,
>> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
>> + * Peter Chen <peter.chen@xxxxxxx>
>> + */
>> +
>
><snip>
>
>> +
>> +static void cdns3_gadget_disable(struct cdns3 *cdns)
>> +{
>> + struct cdns3_device *priv_dev;
>> +
>> + priv_dev = cdns->gadget_dev;
>> +
>> + if (priv_dev->gadget_driver)
>> + priv_dev->gadget_driver->disconnect(&priv_dev->gadget);> +
>> + usb_gadget_disconnect(&priv_dev->gadget);
>> + priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
>> +}
>> +
>> +void cdns3_gadget_exit(struct cdns3 *cdns)
>> +{
>> + struct cdns3_device *priv_dev;
>> +
>> + priv_dev = cdns->gadget_dev;
>> +
>> + cdns3_gadget_disable(cdns);
>> +
>> + devm_free_irq(cdns->dev, cdns->irq, cdns);
>> +
>> + pm_runtime_mark_last_busy(cdns->dev);
>> + pm_runtime_put_autosuspend(cdns->dev);
>> +
>> + usb_del_gadget_udc(&priv_dev->gadget);
>> +
>> + cdns3_free_all_eps(priv_dev);
>> +
>> + dma_free_coherent(priv_dev->sysdev, 8, priv_dev->setup_buf,
>> + priv_dev->setup_dma);
>> +
>> + kfree(priv_dev->zlp_buf);
>> + kfree(priv_dev);
>> + cdns->gadget_dev = NULL;
>> +}
>> +
>> +static int cdns3_gadget_start(struct cdns3 *cdns)
>> +{
>> + struct cdns3_device *priv_dev;
>> + u32 max_speed;
>> + int ret;
>> +
>> + priv_dev = kzalloc(sizeof(*priv_dev), GFP_KERNEL);
>> + if (!priv_dev)
>> + return -ENOMEM;
>> +
>> + cdns->gadget_dev = priv_dev;
>> + priv_dev->sysdev = cdns->dev;
>> + priv_dev->dev = cdns->dev;
>> + priv_dev->regs = cdns->dev_regs;
>> +
>> + max_speed = usb_get_maximum_speed(cdns->dev);
>> +
>> + /* Check the maximum_speed parameter */
>> + switch (max_speed) {
>> + case USB_SPEED_FULL:
>> + case USB_SPEED_HIGH:
>> + case USB_SPEED_SUPER:
>> + break;
>> + default:
>> + dev_err(cdns->dev, "invalid maximum_speed parameter %d\n",
>> + max_speed);
>> + /* fall through */
>> + case USB_SPEED_UNKNOWN:
>> + /* default to superspeed */
>> + max_speed = USB_SPEED_SUPER;
>> + break;
>> + }
>> +
>> + /* fill gadget fields */
>> + priv_dev->gadget.max_speed = max_speed;
>> + priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
>> + priv_dev->gadget.ops = &cdns3_gadget_ops;
>> + priv_dev->gadget.name = "usb-ss-gadget";
>> + priv_dev->gadget.sg_supported = 1;
>> +
>> + spin_lock_init(&priv_dev->lock);
>> + INIT_WORK(&priv_dev->pending_status_wq,
>> + cdns3_pending_setup_status_handler);
>> +
>> + /* initialize endpoint container */
>> + INIT_LIST_HEAD(&priv_dev->gadget.ep_list);
>> +
>> + ret = cdns3_init_eps(priv_dev);
>> + if (ret) {
>> + dev_err(priv_dev->dev, "Failed to create endpoints\n");
>> + goto err1;
>> + }
>> +
>> + /* allocate memory for setup packet buffer */
>> + priv_dev->setup_buf = dma_alloc_coherent(priv_dev->sysdev, 8,
>> + &priv_dev->setup_dma, GFP_DMA);
>> + if (!priv_dev->setup_buf) {
>> + dev_err(priv_dev->dev, "Failed to allocate memory for SETUP buffer\n");
>> + ret = -ENOMEM;
>> + goto err2;
>> + }
>> +
>> + priv_dev->dev_ver = readl(&priv_dev->regs->usb_cap6);
>> + dev_dbg(priv_dev->dev, "Device Controller version: %08x\n",
>> + readl(&priv_dev->regs->usb_cap6));
>> + dev_dbg(priv_dev->dev, "USB Capabilities:: %08x\n",
>> + readl(&priv_dev->regs->usb_cap1));
>> + dev_dbg(priv_dev->dev, "On-Chip memory cnfiguration: %08x\n",
>> + readl(&priv_dev->regs->usb_cap2));
>> +
>> + priv_dev->zlp_buf = kzalloc(CDNS3_EP_ZLP_BUF_SIZE, GFP_KERNEL);
>> + if (!priv_dev->zlp_buf) {
>> + ret = -ENOMEM;
>> + goto err3;
>> + }
>> +
>> + /* add USB gadget device */
>> + ret = usb_add_gadget_udc(priv_dev->dev, &priv_dev->gadget);
>> + if (ret < 0) {
>> + dev_err(priv_dev->dev,
>> + "Failed to register USB device controller\n");
>> + goto err4;
>> + }
>> +
>> + return 0;
>> +err4:
>> + kfree(priv_dev->zlp_buf);
>> +err3:
>> + dma_free_coherent(priv_dev->sysdev, 8, priv_dev->setup_buf,
>> + priv_dev->setup_dma);
>> +err2:
>> + cdns3_free_all_eps(priv_dev);
>> +err1:
>> + cdns->gadget_dev = NULL;
>> + return ret;
>> +}
>> +
>> +static int __cdns3_gadget_init(struct cdns3 *cdns)
>> +{
>> + struct cdns3_device *priv_dev;
>> + unsigned long flags;
>> + int ret = 0;
>> +
>> + ret = cdns3_gadget_start(cdns);
>> + if (ret)
>> + return ret;
>> +
>> + priv_dev = cdns->gadget_dev;
>> + ret = devm_request_threaded_irq(cdns->dev, cdns->irq,
>> + cdns3_device_irq_handler,
>> + cdns3_device_thread_irq_handler,
>> + IRQF_SHARED, dev_name(cdns->dev), cdns);
>> + if (ret)
>> + goto err0;
>> +
>> + pm_runtime_get_sync(cdns->dev);
>pm_runtime_get_sync() should be done before cdns3_gadget_start()
Ok.
>
>> + spin_lock_irqsave(&priv_dev->lock, flags);
>> + spin_unlock_irqrestore(&priv_dev->lock, flags);
>
>Redundant spinlock usage?
>
>> + return 0;
>> +err0:
>> + cdns3_gadget_exit(cdns);
>> + return ret;
>> +}
>> +
>> +static int cdns3_gadget_suspend(struct cdns3 *cdns, bool do_wakeup)
>> +{
>> + cdns3_gadget_disable(cdns);
>
>Does this ensure gadget controller is stopped?

Yes.
>
>> + return 0;
>> +}
>> +
>> +static int cdns3_gadget_resume(struct cdns3 *cdns, bool hibernated)
>> +{
>> + struct cdns3_device *priv_dev;
>> + unsigned long flags;
>> +
>> + priv_dev = cdns->gadget_dev;
>> + spin_lock_irqsave(&priv_dev->lock, flags);
>> +
>> + if (!priv_dev->gadget_driver) {
>> + spin_unlock_irqrestore(&priv_dev->lock, flags);
>> + return 0;
>> + }
>> +
>> + cdns3_gadget_config(priv_dev);
>> + spin_unlock_irqrestore(&priv_dev->lock, flags);
>> + return 0;
>> +}
>> +
>> +/**
>> + * cdns3_gadget_init - initialize device structure
>> + *
>> + * cdns: cdns3 instance
>> + *
>> + * This function initializes the gadget.
>> + */
>> +int cdns3_gadget_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_gadget_init;
>> + rdrv->stop = cdns3_gadget_exit;
>> + rdrv->suspend = cdns3_gadget_suspend;
>> + rdrv->resume = cdns3_gadget_resume;
>> + rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
>> + rdrv->name = "gadget";
>> + cdns->roles[CDNS3_ROLE_GADGET] = rdrv;
>> +
>> + return 0;
>> +}
>
><snip>
>
>--
>cheers,
>-roger
>Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Cheers,
Pawel

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